File: object.c

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/*
 * Crossfire -- cooperative multi-player graphical RPG and adventure game
 *
 * Copyright (c) 1999-2014 Mark Wedel and the Crossfire Development Team
 * Copyright (c) 1992 Frank Tore Johansen
 *
 * Crossfire is free software and comes with ABSOLUTELY NO WARRANTY. You are
 * welcome to redistribute it under certain conditions. For details, please
 * see COPYING and LICENSE.
 *
 * The authors can be reached via e-mail at <crossfire@metalforge.org>.
 */

/**
 * @file common/object.c
 * Everything related to objects, in their basic form.
 */

/* Eneq(@csd.uu.se): Added weight-modifiers in environment of objects.
   object_sub/add_weight will transcend the environment updating the carrying
   variable. */

#include "global.h"

#include <assert.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifndef WIN32 /* ---win32 exclude headers */
#include <sys/types.h>
#include <sys/uio.h>
#endif /* win32 */

#include "loader.h"
#include "object.h"
#include "skills.h"
#include "sproto.h"
#include "stringbuffer.h"

static int compare_ob_value_lists_one(const object *, const object *);
static int compare_ob_value_lists(const object *, const object *);
static void expand_objects(void);
static void permute(int *, int, int);
static int object_set_value_s(object *, const char *, const char *, int);
static void object_increase_nrof(object *op, uint32_t i);

#ifdef MEMORY_DEBUG
int nroffreeobjects = 0;  /**< Number of free objects. */
int nrofallocobjects = 0; /**< Number of allocated objects. */
#undef OBJ_EXPAND
#define OBJ_EXPAND 1
#else
static object objarray[STARTMAX]; /**< All objects, allocated this way at first */
int nroffreeobjects = STARTMAX;  /**< How many OBs allocated and free (free) */
int nrofallocobjects = STARTMAX; /**< How many OBs allocated (free + used) */
#endif

object *objects;           /**< Pointer to the list of used objects */
static object *free_objects;      /**< Pointer to the list of unused objects */
object *active_objects;    /**< List of active objects that need to be processed */

/** X offset when searching around a spot. */
short freearr_x[SIZEOFFREE] = {
    0, 0, 1, 1, 1, 0, -1, -1, -1, 0, 1, 2, 2, 2, 2, 2, 1, 0, -1, -2, -2, -2, -2, -2, -1,
    0, 1, 2, 3, 3, 3, 3, 3, 3, 3, 2, 1, 0, -1, -2, -3, -3, -3, -3, -3, -3, -3, -2, -1
};

/** Y offset when searching around a spot. */
short freearr_y[SIZEOFFREE] = {
    0, -1, -1, 0, 1, 1, 1, 0, -1, -2, -2, -2, -1, 0, 1, 2, 2, 2, 2, 2, 1, 0, -1, -2, -2,
    -3, -3, -3, -3, -2, -1, 0, 1, 2, 3, 3, 3, 3, 3, 3, 3, 2, 1, 0, -1, -2, -3, -3, -3
};

/** Number of spots around a location, including that location (except for 0) */
int maxfree[SIZEOFFREE] = {
    0, 9, 10, 13, 14, 17, 18, 21, 22, 25, 26, 27, 30, 31, 32, 33, 36, 37, 39, 39, 42, 43, 44, 45,
    48, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49
};

/** Direction we're pointing on this spot. */
int freedir[SIZEOFFREE] = {
    0, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 2, 2, 3, 4, 4, 4, 5, 6, 6, 6, 7, 8, 8, 8,
    1, 2, 2, 2, 2, 2, 3, 4, 4, 4, 4, 4, 5, 6, 6, 6, 6, 6, 7, 8, 8, 8, 8, 8
};

/**
 * Sets up and initialises the linked list of free and used objects.
 * Allocates a certain chunk of objects and puts them on the free list.
 * Called by init_library();
 */
void init_objects(void) {
    /* Initialize all objects: */
    objects = NULL;
    active_objects = NULL;

#ifdef MEMORY_DEBUG
    free_objects = NULL;
#else
    free_objects = objarray;
    objarray[0].prev = NULL,
    objarray[0].next = &objarray[1],
    SET_FLAG(&objarray[0], FLAG_REMOVED);
    SET_FLAG(&objarray[0], FLAG_FREED);
    for (int i = 1; i < STARTMAX-1; i++) {
        objarray[i].next = &objarray[i+1];
        objarray[i].prev = &objarray[i-1];
        SET_FLAG(&objarray[i], FLAG_REMOVED);
        SET_FLAG(&objarray[i], FLAG_FREED);
    }
    objarray[STARTMAX-1].next = NULL;
    objarray[STARTMAX-1].prev = &objarray[STARTMAX-2];
    SET_FLAG(&objarray[STARTMAX-1], FLAG_REMOVED);
    SET_FLAG(&objarray[STARTMAX-1], FLAG_FREED);
#endif
}

/**
 * Compares value lists.
 *
 * @param wants
 * what to search
 * @param has
 * where to search.
 * @return
 * TRUE if every key_values in wants has a partner with the same value in has.
 */
static int compare_ob_value_lists_one(const object *wants, const object *has) {
    key_value *wants_field;

    /* n-squared behaviour (see object_get_key_value()), but I'm hoping both
     * objects with lists are rare, and lists stay short. If not, use a
     * different structure or at least keep the lists sorted...
     */

    /* For each field in wants, */
    for (wants_field = wants->key_values; wants_field != NULL; wants_field = wants_field->next) {
        key_value *has_field;

        /* Look for a field in has with the same key. */
        has_field = object_get_key_value(has, wants_field->key);

        if (has_field == NULL) {
            /* No field with that name. */
            return FALSE;
        }

        /* Found the matching field. */
        if (has_field->value != wants_field->value) {
            /* Values don't match, so this half of the comparison is false. */
            return FALSE;
        }

        /* If we get here, we found a match. Now for the next field in wants. */
    }

    /* If we get here, every field in wants has a matching field in has. */
    return TRUE;
}

/**
 * Compares two object lists.
 * @param ob1
 * @param ob2
 * objects to compare.
 * @return
 * TRUE if ob1 has the same key_values as ob2.
 */
static int compare_ob_value_lists(const object *ob1, const object *ob2) {
    /* However, there may be fields in has which aren't partnered in wants,
     * so we need to run the comparison *twice*. :(
     */
    return compare_ob_value_lists_one(ob1, ob2) && compare_ob_value_lists_one(ob2, ob1);
}

/**
 * Examines the 2 objects given to it, and returns true if
 * they can be merged together, including inventory.
 *
 * Note that this function appears a lot longer than the macro it
 * replaces - this is mostly for clarity - a decent compiler should hopefully
 * reduce this to the same efficiency.
 *
 * Check nrof variable *before* calling object_can_merge()
 *
 * Improvements made with merge:  Better checking on potion, and also
 * check weight
 *
 * @param ob1
 * @param ob2
 * objects to try to merge.
 * @return
 * TRUE if they can be merged, FALSE else.
 *
 * @todo
 * check the function at places marked.
 */
int object_can_merge(object *ob1, object *ob2) {
    /* A couple quicksanity checks */
    if (ob1 == ob2 || ob1->type != ob2->type)
        return 0;

    if (ob1->speed != ob2->speed)
        return 0;
    /* Note sure why the following is the case - either the object has to
     * be animated or have a very low speed.  Is this an attempted monster
     * check?
     */
    /*TODO is this check really needed?*/
    if (!QUERY_FLAG(ob1, FLAG_ANIMATE) && FABS((ob1)->speed) > MIN_ACTIVE_SPEED)
        return 0;

    /* Do not merge objects if nrof would overflow. We use 1UL<<31 since that
     * value could not be stored in a int32_t (which unfortunately sometimes is
     * used to store nrof).
     */
    if (ob1->nrof+ob2->nrof >= 1UL<<31)
        return 0;

    /* This is really a spellbook check - really, we should
     * check all objects in the inventory.
    */
    /*TODO is this check really needed?*/
    if (ob1->inv || ob2->inv) {
        /* if one object has inventory but the other doesn't, not equiv */
        if ((ob1->inv && !ob2->inv) || (ob2->inv && !ob1->inv))
            return 0;

        /* Now check to see if the two inventory objects could merge */
        if (!object_can_merge(ob1->inv, ob2->inv))
            return 0;

        /* inventory ok - still need to check rest of this object to see
         * if it is valid.
         */
    }

    /* If the objects have been identified, set the BEEN_APPLIED flag.
     * This is to the comparison of the flags below will be OK.  We
     * just can't ignore the been applied or identified flags, as they
     * are not equal - just if it has been identified, the been_applied
     * flags lose any meaning.
     */

    /*TODO is this hack on BEEN_APPLIED really needed? */
    if (QUERY_FLAG(ob1, FLAG_IDENTIFIED))
        SET_FLAG(ob1, FLAG_BEEN_APPLIED);

    if (QUERY_FLAG(ob2, FLAG_IDENTIFIED))
        SET_FLAG(ob2, FLAG_BEEN_APPLIED);


    /* Note: FLAG_INV_LOCKED is ignored for merging purposes */
    if ((ob1->arch != ob2->arch)
    || (ob1->flags[0] != ob2->flags[0])
    || (ob1->flags[1] != ob2->flags[1])
    || (ob1->flags[2] != ob2->flags[2])
    || ((ob1->flags[3]&~0x84) != (ob2->flags[3]&~0x84)) /* ignore CLIENT_SENT and FLAG_OBJ_ORIGINAL */
    || (ob1->name != ob2->name)
    || (ob1->title != ob2->title)
    || (ob1->msg != ob2->msg)
    || (ob1->weight != ob2->weight)
    || (ob1->item_power != ob2->item_power)
    || (memcmp(&ob1->resist, &ob2->resist, sizeof(ob1->resist)) != 0)
    || (memcmp(&ob1->stats, &ob2->stats, sizeof(ob1->stats)) != 0)
    || (ob1->attacktype != ob2->attacktype)
    || (ob1->magic != ob2->magic)
    || (ob1->slaying != ob2->slaying)
    || (ob1->skill != ob2->skill)
    || (ob1->value != ob2->value)
    || (ob1->animation != ob2->animation)
    || (ob1->client_type != ob2->client_type)
    || (ob1->materialname != ob2->materialname)
    || (ob1->lore != ob2->lore)
    || (ob1->subtype != ob2->subtype)
    || (ob1->move_type != ob2->move_type)
    || (ob1->move_block != ob2->move_block)
    || (ob1->move_allow != ob2->move_allow)
    || (ob1->move_on != ob2->move_on)
    || (ob1->move_off != ob2->move_off)
    || (ob1->move_slow != ob2->move_slow)
    || (ob1->move_slow_penalty != ob2->move_slow_penalty)
    || (ob1->map_layer != ob2->map_layer))
        return 0;

    /* Don't merge objects that are applied.  With the new 'body' code,
     * it is possible for most any character to have more than one of
     * some items equipped, and we don't want those to merge.
     */
    if (QUERY_FLAG(ob1, FLAG_APPLIED) || QUERY_FLAG(ob2, FLAG_APPLIED))
        return 0;

    if (ob1->key_values != NULL || ob2->key_values != NULL) {
        /* At least one of these has key_values. */
        if ((ob1->key_values == NULL) != (ob2->key_values == NULL)) {
            /* One has fields, but the other one doesn't. */
            return 0;
        } else {
            if (!compare_ob_value_lists(ob1, ob2)) {
                return 0;
            }
        }
    }

    /*TODO should this really be limited to scrolls?*/
    switch (ob1->type) {
    case SCROLL:
        if (ob1->level != ob2->level)
            return 0;
        break;
    }

    /* Don't merge items with differing custom names. */
    if (ob1->custom_name != ob2->custom_name)
        return 0;

    /* Everything passes, must be OK. */
    return 1;
}

/**
 * object_sum_weight() is a recursive function which calculates the weight
 * an object is carrying.  It goes through in figures out how much
 * containers are carrying, and sums it up.
 *
 * This takes into account the container's weight reduction.
 *
 * @param op
 * object we want the weight of.
 * @return
 * weight of this item and all its inventory.
 *
 * @note
 * The object's carrying field is updated.
 */
/* TODO should check call this this are made a place where we really need reevaluaton of whole tree */
signed long object_sum_weight(object *op) {
    signed long sum;

    sum = 0;
    FOR_INV_PREPARE(op, inv) {
        if (inv->inv)
            object_sum_weight(inv);
        sum += inv->carrying+inv->weight*NROF(inv);
    } FOR_INV_FINISH();
    if (op->type == CONTAINER && op->stats.Str)
        sum = (sum*(100-op->stats.Str))/100;
    op->carrying = sum;
    return sum;
}

/**
 * Utility function.
 * @param op
 * object we want the environment of. Can't be NULL.
 * @return
 * the outermost environment object for a given object. Will not be NULL.
 */
object *object_get_env_recursive(object *op) {
    while (op->env != NULL)
        op = op->env;
    return op;
}

/**
 * Finds the player carrying an object.
 *
 * @param op
 * item for which we want the carrier (player).
 * @return
 * the player, or NULL if not in an inventory.
 *
 * @todo
 * this function is badly named. Fix patching on the fly.
 */
object *object_get_player_container(object *op) {
    for (; op != NULL && op->type != PLAYER; op = op->env)
        /*TODO this is patching the structure on the flight as side effect. Shoudln't be needed in clean code */
        if (op->env == op)
            op->env = NULL;
    return op;
}

/**
 * Returns the object which this object marks as being the owner, constant version.
 * Mostly written for object_dump, which takes a const object.
 *
 * @param op
 * item to search owner of.
 * @return
 * owner, or NULL if not found.
 */
static const object *object_get_owner_const(const object *op) {
    if (op->owner == NULL)
        return NULL;

    if (!QUERY_FLAG(op->owner, FLAG_FREED)
         && !QUERY_FLAG(op->owner, FLAG_REMOVED)
         && op->owner->count == op->ownercount)
        return op->owner;

    LOG(llevError, "Warning, no owner found\n");
    return NULL;
}

/**
 * Dumps an object.
 *
 * @param op
 * object to dump. Can be NULL.
 * @param sb
 * buffer that will contain object information. Must not be NULL.
 */
void object_dump(const object *op, StringBuffer *sb) {
    if (op == NULL) {
        stringbuffer_append_string(sb, "[NULL pointer]");
        return;
    }

    /*  object *tmp;*/

    if (op->arch != NULL) {
        const object *owner;

        stringbuffer_append_string(sb, "arch ");
        stringbuffer_append_string(sb, op->arch->name ? op->arch->name : "(null)");
        stringbuffer_append_string(sb, "\n");

        if (op->artifact != NULL) {
            stringbuffer_append_string(sb, "artifact ");
            stringbuffer_append_string(sb, op->artifact);
            stringbuffer_append_string(sb, "\n");
        }

        get_ob_diff(sb, op, &empty_archetype->clone);
        if (op->more) {
            stringbuffer_append_printf(sb, "more %u\n", op->more->count);
        }
        if (op->head) {
            stringbuffer_append_printf(sb, "head %u\n", op->head->count);
        }
        if (op->env) {
            stringbuffer_append_printf(sb, "env %u\n", op->env->count);
        }
        if (op->inv) {
            stringbuffer_append_printf(sb, "inv %u\n", op->inv->count);
        }
        owner = object_get_owner_const(op);
        if (owner != NULL) {
            stringbuffer_append_printf(sb, "owner %u\n", owner->count);
        }
        stringbuffer_append_string(sb, "end\n");
    } else {
        stringbuffer_append_string(sb, "Object ");
        stringbuffer_append_string(sb, op->name == NULL ? "(null)" : op->name);
        stringbuffer_append_string(sb, "\nend\n");
    }
}

/**
 * Dumps all objects to console.
 *
 * This is really verbose...Can be triggered by the dumpallobjects command while in DM mode.
 *
 * All objects are dumped to stderr (or alternate logfile, if in server-mode)
 */
void object_dump_all(void) {
    object *op;

    for (op = objects; op != NULL; op = op->next) {
        StringBuffer *sb;
        char *diff;

        sb = stringbuffer_new();
        object_dump(op, sb);
        diff = stringbuffer_finish(sb);
        LOG(llevDebug, "Object %u\n:%s\n", op->count, diff);
        free(diff);
    }
}

/**
 * Returns the object which has the count-variable equal to the argument.
 *
 * @param i
 * tag.
 * @return
 * matching object, NULL if not found.
 */
object *object_find_by_tag_global(tag_t i) {
    object *op;

    for (op = objects; op != NULL; op = op->next)
        if (op->count == i)
            break;
    return op;
}

/**
 * Finds an object by name.
 *
 * Used only by the patch command, but not all that useful.
 * Enables features like "patch name-of-other-player food 999"
 *
 * @param str
 * name to search for. Must not be allocated by add_string().
 * @return
 * the first object which has a name equal to the argument.
 */
object *object_find_by_name_global(const char *str) {
    const char *name = add_string(str);
    object *op;

    for (op = objects; op != NULL; op = op->next)
        if (op->name == name)
            break;
    free_string(name);
    return op;
}

/**
 * Destroys all allocated objects.
 *
 * @note
 * free() is called instead of object_free_drop_inventory() as the object's memory has already by cleaned.
 *
 * @warning
 * this should be the last method called.
 */
void object_free_all_data(void) {
#ifdef MEMORY_DEBUG
    object *op, *next;

    for (op = free_objects; op != NULL; ) {
        next = op->next;
        free(op);
        nrofallocobjects--;
        nroffreeobjects--;
        op = next;
    }
    free_objects = NULL;

    for (op = objects; op != NULL; ) {
        next = op->next;
        if (!QUERY_FLAG(op, FLAG_FREED)) {
            LOG(llevDebug, "non freed object: %s\n", op->name);
        }
        op = next;
    }
#endif

    LOG(llevDebug, "%d allocated objects, %d free objects, STARMAX=%d\n", nrofallocobjects, nroffreeobjects, STARTMAX);
}

/**
 * Returns the object which this object marks as being the owner.
 *
 * A id-scheme is used to avoid pointing to objects which have been
 * freed and are now reused.  If this is detected, the owner is
 * set to NULL, and NULL is returned.
 *
 * @param op
 * item to search owner of.
 * @return
 * owner, or NULL if not found.
 */
object *object_get_owner(object *op) {
    if (op->owner == NULL)
        return NULL;

    if (!QUERY_FLAG(op->owner, FLAG_FREED)
    && !QUERY_FLAG(op->owner, FLAG_REMOVED)
    && op->owner->count == op->ownercount)
        return op->owner;

    object_clear_owner(op);
    return NULL;
}

/**
 * Clears the owner of specified object.
 *
 * @param op
 * object we want to clear the owner of. Can be NULL.
 */
void object_clear_owner(object *op) {
    if (!op)
        return;

    op->owner = NULL;
    op->ownercount = 0;
}

/**
 * Sets the owner and sets the skill and exp pointers to owner's current
 * skill and experience objects.
 *
 * @param op
 * object of which to set the owner
 * @param owner
 * new owner for object. Can be NULL, in which case it's equivalent of calling object_clear_owner(op)
 */
void object_set_owner(object *op, object *owner) {
    /* Assign temp to something, so it can't accidentally be NULL */
    object *tmp = owner;
    if (op == NULL)
        return;
    if (owner == NULL) {
        object_clear_owner(op);
        return;
    }

    /* next line added to allow objects which own objects */
    /* Add a check for ownercounts in here, as I got into an endless loop
     * with the fireball owning a poison cloud which then owned the
     * fireball.  I believe that was caused by one of the objects getting
     * freed and then another object replacing it.  Since the ownercounts
     * didn't match, this check is valid and I believe that cause is valid.
     */
    /*
     * if owner is NULL, function will have already returned,
     * so loop should still function as before.
     */
    while (tmp) {
        tmp = object_get_owner(owner);
        if (tmp)
            owner = tmp;
    }

    /* must not cause owner cycles */
    assert(op != owner);

    if (op->owner != NULL)
        object_clear_owner(op);

    op->owner = owner;
    op->ownercount = owner->count;
}

/**
 * Set the owner to clone's current owner and set the skill and experience
 * objects to clone's objects (typically those objects that where the owner's
 * current skill and experience objects at the time when clone's owner was
 * set - not the owner's current skill and experience objects).
 *
 * Use this function if player created an object (e.g. fire bullet, swarm
 * spell), and this object creates further objects whose kills should be
 * accounted for the player's original skill, even if player has changed
 * skills meanwhile.
 *
 * @param op
 * object to update.
 * @param clone
 * object from which to get the owner.
 */
void object_copy_owner(object *op, object *clone) {
    object *owner = object_get_owner(clone);
    if (owner == NULL) {
        /* players don't have owners - they own themselves.  Update
         * as appropriate.
         */
        /*TODO owner=self is dangerous and should be avoided*/
        if (clone->type != PLAYER)
            return;
        owner = clone;
    }
    object_set_owner(op, owner);
}

/**
 * Sets the enemy of an object.
 *
 * @param op
 * the object of which to set the enemy
 * @param enemy
 * the new enemy for op; can be NULL to clear the enemy
 */
void object_set_enemy(object *op, object *enemy) {
    if (op->enemy == enemy) {
        return;
    }

#if 0
    if (op->type != PLAYER) {
        LOG(llevDebug, "object_set_enemy: %s(%lu)->enemy=%s(%lu)\n", op->name, op->count, enemy == NULL ? "NONE" : enemy->name, enemy == NULL ? 0 : enemy->count);
    }
#endif
    op->enemy = enemy;
}

/**
 * Totally resets the specified object, without freeing associated memory.
 *
 * @param op
 * object to reset.
 */
void object_reset(object *op) {
    op->name = NULL;
    op->name_pl = NULL;
    op->title = NULL;
    op->race = NULL;
    op->slaying = NULL;
    op->skill = NULL;
    op->msg = NULL;
    op->materialname = NULL;
    op->lore = NULL;
    object_clear(op);
}

/**
 * Zero the key_values on op, decrementing the shared-string
 * refcounts and freeing the links.
 *
 * @param op
 * object to clear.
 */
void object_free_key_values(object *op) {
    key_value *i;
    key_value *next = NULL;

    if (op->key_values == NULL)
        return;

    for (i = op->key_values; i != NULL; i = next) {
        /* Store next *first*. */
        next = i->next;

        if (i->key)
            FREE_AND_CLEAR_STR(i->key);
        if (i->value)
            FREE_AND_CLEAR_STR(i->value);
        i->next = NULL;
        free(i);
    }

    op->key_values = NULL;
}

/**
 * Frees everything allocated by an object, and also
 * clears all variables and flags to default settings.
 *
 * @param op
 * object to clear
 */
void object_clear(object *op) {
    /*TODO this comment must be investigated*/
    /* redo this to be simpler/more efficient. Was also seeing
     * crashes in the old code.  Move this to the top - am
     * seeing periodic crashes in this code, and would like to have
     * as much info available as possible (eg, object name).
     */
    object_free_key_values(op);
    free_dialog_information(op);

    /* the memset will clear all these values for us, but we need
     * to reduce the refcount on them.
     */
    if (op->name != NULL)
        FREE_AND_CLEAR_STR(op->name);
    if (op->name_pl != NULL)
        FREE_AND_CLEAR_STR(op->name_pl);
    if (op->title != NULL)
        FREE_AND_CLEAR_STR(op->title);
    if (op->race != NULL)
        FREE_AND_CLEAR_STR(op->race);
    if (op->slaying != NULL)
        FREE_AND_CLEAR_STR(op->slaying);
    if (op->skill != NULL)
        FREE_AND_CLEAR_STR(op->skill);
    if (op->msg != NULL)
        FREE_AND_CLEAR_STR(op->msg);
    if (op->lore != NULL)
        FREE_AND_CLEAR_STR(op->lore);
    if (op->materialname != NULL)
        FREE_AND_CLEAR_STR(op->materialname);

    /* Remove object from friendly list if needed. */
    if (QUERY_FLAG(op, FLAG_FRIENDLY))
        remove_friendly_object(op);

    memset((void *)((char *)op+offsetof(object, name)), 0, sizeof(object)-offsetof(object, name));
    /* Below here, we clear things that are not done by the memset,
     * or set default values that are not zero.
     */
    /* This is more or less true */
    SET_FLAG(op, FLAG_REMOVED);


    op->contr = NULL;
    op->below = NULL;
    op->above = NULL;
    op->inv = NULL;
    op->container = NULL;
    op->env = NULL;
    op->more = NULL;
    op->head = NULL;
    op->map = NULL;
    op->active_next = NULL;
    op->active_prev = NULL;
    /* What is not cleared is next, prev, and count */

    op->expmul = 1.0;
    op->face = blank_face;
    op->attacked_by_count = -1;
    if (settings.casting_time)
        op->casting_time = -1;
}

/**
 * Copy object first frees everything allocated by the second object,
 * and then copies the contents of the first object into the second
 * object, allocating what needs to be allocated.  Basically, any
 * data that is malloc'd needs to be re-malloc/copied.  Otherwise,
 * if the first object is freed, the pointers in the new object
 * will point at garbage.
 *
 * @param src_ob
 * object that we copy.from
 * @param dest_ob
 * object that we copy to.
 */
void object_copy(const object *src_ob, object *dest_ob) {
    int is_freed = QUERY_FLAG(dest_ob, FLAG_FREED), is_removed = QUERY_FLAG(dest_ob, FLAG_REMOVED);

    /* Decrement the refcounts, but don't bother zeroing the fields;
    they'll be overwritten by memcpy. */
    if (dest_ob->artifact != NULL)
        free_string(dest_ob->artifact);
    if (dest_ob->name != NULL)
        free_string(dest_ob->name);
    if (dest_ob->name_pl != NULL)
        free_string(dest_ob->name_pl);
    if (dest_ob->anim_suffix != NULL)
        free_string(dest_ob->anim_suffix);
    if (dest_ob->title != NULL)
        free_string(dest_ob->title);
    if (dest_ob->race != NULL)
        free_string(dest_ob->race);
    if (dest_ob->slaying != NULL)
        free_string(dest_ob->slaying);
    if (dest_ob->skill != NULL)
        free_string(dest_ob->skill);
    if (dest_ob->msg != NULL)
        free_string(dest_ob->msg);
    if (dest_ob->lore != NULL)
        free_string(dest_ob->lore);
    if (dest_ob->materialname != NULL)
        free_string(dest_ob->materialname);
    if (dest_ob->custom_name != NULL)
        free_string(dest_ob->custom_name);
    if (dest_ob->spell_tags != NULL)
        FREE_AND_CLEAR(dest_ob->spell_tags);

    /* Basically, same code as from object_clear() */

    object_free_key_values(dest_ob);
    free_dialog_information(dest_ob);

    /* Copy all attributes below name (name included). */
    (void)memcpy((void *)((char *)dest_ob+offsetof(object, name)),
                (void *)((char *)src_ob+offsetof(object, name)),
                sizeof(object)-offsetof(object, name));

    if (is_freed)
        SET_FLAG(dest_ob, FLAG_FREED);
    if (is_removed)
        SET_FLAG(dest_ob, FLAG_REMOVED);
    if (dest_ob->artifact != NULL)
        add_refcount(dest_ob->artifact);
    if (dest_ob->name != NULL)
        add_refcount(dest_ob->name);
    if (dest_ob->name_pl != NULL)
        add_refcount(dest_ob->name_pl);
    if (dest_ob->anim_suffix != NULL)
        add_refcount(dest_ob->anim_suffix);
    if (dest_ob->title != NULL)
        add_refcount(dest_ob->title);
    if (dest_ob->race != NULL)
        add_refcount(dest_ob->race);
    if (dest_ob->slaying != NULL)
        add_refcount(dest_ob->slaying);
    if (dest_ob->skill != NULL)
        add_refcount(dest_ob->skill);
    if (dest_ob->lore != NULL)
        add_refcount(dest_ob->lore);
    if (dest_ob->msg != NULL)
        add_refcount(dest_ob->msg);
    if (dest_ob->custom_name != NULL)
        add_refcount(dest_ob->custom_name);
    if (dest_ob->materialname != NULL)
        add_refcount(dest_ob->materialname);

    if (dest_ob->spell_tags != NULL) {
        dest_ob->spell_tags = malloc(sizeof(tag_t)*SPELL_TAG_SIZE);
        memcpy(dest_ob->spell_tags, src_ob->spell_tags, sizeof(tag_t)*SPELL_TAG_SIZE);
    }

    /* If archetype is a temporary one, we need to update reference count, because
     * that archetype will be freed by object_free_drop_inventory() when the last object is removed.
     */
    if (dest_ob->arch->reference_count > 0)
        dest_ob->arch->reference_count++;

    if (src_ob->speed < 0)
        dest_ob->speed_left = src_ob->speed_left-RANDOM()%200/100.0;

    /* Copy over key_values, if any. */
    if (src_ob->key_values != NULL) {
        key_value *tail = NULL;
        key_value *i;

        dest_ob->key_values = NULL;

        for (i = src_ob->key_values; i != NULL; i = i->next) {
            key_value *new_link = malloc(sizeof(key_value));

            new_link->next = NULL;
            new_link->key = add_refcount(i->key);
            if (i->value)
                new_link->value = add_refcount(i->value);
            else
                new_link->value = NULL;

            /* Try and be clever here, too. */
            if (dest_ob->key_values == NULL) {
                dest_ob->key_values = new_link;
                tail = new_link;
            } else {
                tail->next = new_link;
                tail = new_link;
            }
        }
    }

    /* This way, dialog information will be parsed again when/if needed. */
    CLEAR_FLAG(dest_ob, FLAG_DIALOG_PARSED);

    object_update_speed(dest_ob);
}

/**
 * Copy an object with an inventory, duplicate the inv too.
 * @param src_ob
 * object to copy.
 * @param dest_ob
 * where to copy.
 * @todo
 * replace with a function in common library (there is certainly one).
 */
void object_copy_with_inv(const object *src_ob, object *dest_ob) {
    object_copy(src_ob, dest_ob);
    FOR_INV_PREPARE(src_ob, walk) {
        object *tmp;

        tmp = object_new();
        object_copy_with_inv(walk, tmp);
        object_insert_in_ob(tmp, dest_ob);
    } FOR_INV_FINISH();
}

/**
 * Allocates more objects for the list of unused objects.
 *
 * It is called from object_new() if the unused list is empty.
 *
 * If there is not enough memory, fatal() is called.
 */
static void expand_objects(void) {
    int i;
    object *new;

    new = (object *)CALLOC(OBJ_EXPAND, sizeof(object));

    if (new == NULL)
        fatal(OUT_OF_MEMORY);
    free_objects = new;
    new[0].prev = NULL;
    new[0].next = &new[1],
    SET_FLAG(&new[0], FLAG_REMOVED);
    SET_FLAG(&new[0], FLAG_FREED);

    for (i = 1; i < OBJ_EXPAND-1; i++) {
        new[i].next = &new[i+1],
        new[i].prev = &new[i-1],
        SET_FLAG(&new[i], FLAG_REMOVED);
        SET_FLAG(&new[i], FLAG_FREED);
    }
    new[OBJ_EXPAND-1].prev = &new[OBJ_EXPAND-2],
    new[OBJ_EXPAND-1].next = NULL,
    SET_FLAG(&new[OBJ_EXPAND-1], FLAG_REMOVED);
    SET_FLAG(&new[OBJ_EXPAND-1], FLAG_FREED);

    nrofallocobjects += OBJ_EXPAND;
    nroffreeobjects += OBJ_EXPAND;
}

/**
 * Grabs an object from the list of unused objects, makes
 * sure it is initialised, and returns it.
 *
 * If there are no free objects, expand_objects() is called to get more.
 *
 * @return
 * cleared and ready to use object*.
 *
 * @note
 * will never fail, as expand_objects() will fatal() if memory allocation error.
 */
object *object_new(void) {
    object *op;
#ifdef MEMORY_DEBUG
    /* FIXME: However this doesn't work since object_free() sometimes add
     * objects back to the free_objects linked list, and some functions mess
     * with the object after return of object_free(). This is bad and should be
     * fixed. But it would need fairly extensive changes and a lot of debugging.
     */
    op = calloc(1, sizeof(object));
    if (op == NULL)
        fatal(OUT_OF_MEMORY);
#else
    if (free_objects == NULL) {
        expand_objects();
    }
    op = free_objects;
    if (!QUERY_FLAG(op, FLAG_FREED)) {
        LOG(llevError, "Fatal: Getting busy object.\n");
#ifdef MANY_CORES
        abort();
#endif
    }
    free_objects = op->next;
    if (free_objects != NULL)
        free_objects->prev = NULL;
    nroffreeobjects--;
#endif
    op->count = ++ob_count;
    op->name = NULL;
    op->name_pl = NULL;
    op->title = NULL;
    op->race = NULL;
    op->slaying = NULL;
    op->skill = NULL;
    op->lore = NULL;
    op->msg = NULL;
    op->materialname = NULL;
    op->next = objects;
    op->prev = NULL;
    op->active_next = NULL;
    op->active_prev = NULL;
    op->spell_tags = NULL;
    if (objects != NULL)
        objects->prev = op;
    objects = op;
    object_clear(op);
    SET_FLAG(op, FLAG_REMOVED);
    return op;
}

/**
 * If an object with the IS_TURNABLE() flag needs to be turned due
 * to the closest player being on the other side, this function can
 * be called to update the face variable, _and_ how it looks on the map.
 *
 * @param op
 * object to update.
 */
void object_update_turn_face(object *op) {
    if (op->animation == 0 || !QUERY_FLAG(op, FLAG_IS_TURNABLE))
        return;
    animate_object(op, op->direction);
}

/**
 * Updates the speed of an object.  If the speed changes from 0 to another
 * value, or vice versa, then add/remove the object from the active list.
 * This function needs to be called whenever the speed of an object changes.
 *
 * @param op
 * object to update. Must not be freed and still have a speed.
 *
 * @todo
 * check fixme & todo
 */
void object_update_speed(object *op) {
    /* FIXME what the hell is this crappy hack?*/
    extern int arch_init;

    /* No reason putting the archetypes objects on the speed list,
     * since they never really need to be updated.
     */

    if (QUERY_FLAG(op, FLAG_FREED) && op->speed) {
        LOG(llevError, "Object %s is freed but has speed.\n", op->name);
#ifdef MANY_CORES
        abort();
#else
        op->speed = 0;
#endif
    }
    if (arch_init) {
        return;
    }
    if (FABS(op->speed) > MIN_ACTIVE_SPEED) {
        /* If already on active list, don't do anything */
        /* TODO this check can probably be simplified a lot */
        if (op->active_next || op->active_prev || op == active_objects)
            return;

        /* process_events() expects us to insert the object at the beginning
         * of the list. */
        op->active_next = active_objects;
        if (op->active_next != NULL)
            op->active_next->active_prev = op;
        active_objects = op;
    } else {
        /* If not on the active list, nothing needs to be done */
        if (!op->active_next && !op->active_prev && op != active_objects)
            return;

        if (op->active_prev == NULL) {
            active_objects = op->active_next;
            if (op->active_next != NULL)
                op->active_next->active_prev = NULL;
        } else {
            op->active_prev->active_next = op->active_next;
            if (op->active_next)
                op->active_next->active_prev = op->active_prev;
        }
        op->active_next = NULL;
        op->active_prev = NULL;
    }
}

/**
 * This function removes object 'op' from the list of active
 * objects.
 * This should only be used for style maps or other such
 * reference maps where you don't want an object that isn't
 * in play chewing up cpu time getting processed.
 * The reverse of this is to call object_update_speed(), which
 * will do the right thing based on the speed of the object.
 *
 * @param op
 * object to remove.
 */
void object_remove_from_active_list(object *op) {
    /* If not on the active list, nothing needs to be done */
    if (!op->active_next && !op->active_prev && op != active_objects)
        return;

    if (op->active_prev == NULL) {
        active_objects = op->active_next;
        if (op->active_next != NULL)
            op->active_next->active_prev = NULL;
    } else {
        op->active_prev->active_next = op->active_next;
        if (op->active_next)
            op->active_next->active_prev = op->active_prev;
    }
    op->active_next = NULL;
    op->active_prev = NULL;
}

/**
 * object_update() updates the array which represents the map.
 *
 * It takes into account invisible objects (and represent squares covered
 * by invisible objects by whatever is below them (unless it's another
 * invisible object, etc...)
 *
 * If the object being updated is beneath a player, the look-window
 * of that player is updated (this might be a suboptimal way of
 * updating that window, though, since object_update() is called _often_)
 *
 * @param op
 * object to update
 * @param action
 * Hint of what the caller believes need to be done. One of @ref UP_OBJ_xxx "UP_OBJ_xxx" values.
 * For example, if the only thing that has changed is the face (due to
 * an animation), we don't need to call update_position until that actually
 * comes into view of a player.  OTOH, many other things, like addition/removal
 * of walls or living creatures may need us to update the flags now.
 *
 * @todo
 * this function should be renamed to something like object_update_map, object_update is a too general term
 * Also it might be worth moving it to map.c
 */
void object_update(object *op, int action) {
    int update_now = 0, flags;
    MoveType move_on, move_off, move_block, move_slow;
    object *pl;

    if (op == NULL) {
        /* this should never happen */
        LOG(llevDebug, "object_update() called for NULL object.\n");
        return;
    }

    if (op->env != NULL) {
        /* Animation is currently handled by client, so nothing
        * to do in this case.
        */
        return;
    }

    /* If the map is saving, don't do anything as everything is
     * going to get freed anyways.
     */
    if (!op->map || op->map->in_memory == MAP_SAVING)
        return;

    /* make sure the object is within map boundaries */
    if (op->x < 0 || op->x >= MAP_WIDTH(op->map)
    || op->y < 0 || op->y >= MAP_HEIGHT(op->map)) {
        LOG(llevError, "object_update() called for object out of map!\n");
#ifdef MANY_CORES
        abort();
#endif
        return;
    }

    flags = GET_MAP_FLAGS(op->map, op->x, op->y);
    SET_MAP_FLAGS(op->map, op->x, op->y, flags|P_NEED_UPDATE);
    move_slow = GET_MAP_MOVE_SLOW(op->map, op->x, op->y);
    move_on = GET_MAP_MOVE_ON(op->map, op->x, op->y);
    move_block = GET_MAP_MOVE_BLOCK(op->map, op->x, op->y);
    move_off = GET_MAP_MOVE_OFF(op->map, op->x, op->y);

    if (action == UP_OBJ_INSERT) {
        if (QUERY_FLAG(op, FLAG_BLOCKSVIEW) && !(flags&P_BLOCKSVIEW))
            update_now = 1;

        if (QUERY_FLAG(op, FLAG_NO_MAGIC) && !(flags&P_NO_MAGIC))
            update_now = 1;

        if (QUERY_FLAG(op, FLAG_DAMNED) && !(flags&P_NO_CLERIC))
            update_now = 1;

        if (QUERY_FLAG(op, FLAG_ALIVE) && !(flags&P_IS_ALIVE))
            update_now = 1;

        if ((move_on|op->move_on) != move_on)
            update_now = 1;
        if ((move_off|op->move_off) != move_off)
            update_now = 1;
        /* This isn't perfect, but I don't expect a lot of objects to
         * to have move_allow right now.
         */
        if (((move_block|op->move_block)&~op->move_allow) != move_block)
            update_now = 1;
        if ((move_slow|op->move_slow) != move_slow)
            update_now = 1;

        if (op->type == PLAYER)
            update_now = 1;
    /* if the object is being removed, we can't make intelligent
     * decisions, because object_remove() can't really pass the object
     * that is being removed.
     */
    } else if (action == UP_OBJ_REMOVE) {
        update_now = 1;
    } else if (action == UP_OBJ_FACE || action == UP_OBJ_CHANGE) {
        /* In addition to sending info to client, need to update space
         * information.
         */
        if (action == UP_OBJ_CHANGE)
            update_now = 1;

        /* There is a player on this space - we may need to send an
         * update to the client.
         * If this object is supposed to be animated by the client,
         * nothing to do here - let the client animate it.
         * We can't use FLAG_ANIMATE, as that is basically set for
         * all objects with multiple faces, regardless if they are animated.
         * (levers have it set for example).
         */
        if (flags&P_PLAYER
        && !QUERY_FLAG(op, FLAG_CLIENT_ANIM_SYNC)
        && !QUERY_FLAG(op, FLAG_CLIENT_ANIM_RANDOM)) {
            pl = GET_MAP_PLAYER(op->map, op->x, op->y);

            /* If update_look is set, we're going to send this entire space
             * to the client, so no reason to send face information now.
             */
            if (!pl->contr->socket.update_look) {
                esrv_update_item(UPD_FACE, pl, op);
            }
        }
    } else {
        LOG(llevError, "object_update called with invalid action: %d\n", action);
    }

    if (update_now) {
        SET_MAP_FLAGS(op->map, op->x, op->y, flags|P_NO_ERROR|P_NEED_UPDATE);
        update_position(op->map, op->x, op->y);
    }

    if (op->more != NULL)
        object_update(op->more, action);
}

/**
 * Frees everything allocated by an object, removes
 * it from the list of used objects, and puts it on the list of
 * free objects.  The IS_FREED() flag is set in the object.
 * The object must have been removed by object_remove() first for
 * this function to succeed.
 *
 * Inventory will be dropped on the ground if in a map, else freed too.
 *
 * @param ob
 * object to free. Will become invalid when function returns.
 */
void object_free_drop_inventory(object *ob) {
    object_free(ob, 0);
}

/**
 * Frees everything allocated by an object, removes
 * it from the list of used objects, and puts it on the list of
 * free objects.  The IS_FREED() flag is set in the object.
 *
 * The object must have been removed by object_remove() first for
 * this function to succeed.
 *
 * @param ob
 * object to free. Will become invalid when function returns.
 * @param flags
 * the flags; see FREE_OBJ_xxx constants.
 *
 * @warning
 * the object's archetype should be a valid pointer, or NULL.
 */
void object_free(object *ob, int flags) {
    if (!QUERY_FLAG(ob, FLAG_REMOVED)) {
        StringBuffer *sb;
        char *diff;

        LOG(llevDebug, "Free object called with non removed object\n");
        sb = stringbuffer_new();
        object_dump(ob, sb);
        diff = stringbuffer_finish(sb);
        LOG(llevError, "%s", diff);
        free(diff);
#ifdef MANY_CORES
        abort();
#endif
    }
    if (QUERY_FLAG(ob, FLAG_FRIENDLY)) {
        LOG(llevMonster, "Warning: tried to free friendly object.\n");
        remove_friendly_object(ob);
    }
    if (QUERY_FLAG(ob, FLAG_FREED)) {
        StringBuffer *sb;
        char *diff;

        sb = stringbuffer_new();
        object_dump(ob, sb);
        diff = stringbuffer_finish(sb);
        LOG(llevError, "Trying to free freed object.\n%s\n", diff);
        free(diff);
        return;
    }

    if ((flags & FREE_OBJ_NO_DESTROY_CALLBACK) == 0) {
        /* Handle for plugin destroy event */
        execute_event(ob, EVENT_DESTROY, NULL, NULL, NULL, SCRIPT_FIX_NOTHING);
    }

    if (ob->inv) {
        /* Only if the space blocks everything do we not process -
         * if some form of movemnt is allowed, let objects
         * drop on that space.
         */
        if ((flags & FREE_OBJ_FREE_INVENTORY) != 0
        || ob->map == NULL
        || ob->map->in_memory != MAP_IN_MEMORY
        || (GET_MAP_MOVE_BLOCK(ob->map, ob->x, ob->y) == MOVE_ALL)) {
            FOR_INV_PREPARE(ob, op) {
                object_remove(op);
                object_free(op, flags);
            } FOR_INV_FINISH();
        } else { /* Put objects in inventory onto this space */
            FOR_INV_PREPARE(ob, op) {
                object_remove(op);
                /* No drop means no drop, including its inventory */
                if (QUERY_FLAG(op, FLAG_NO_DROP))
                    object_free(op, FREE_OBJ_FREE_INVENTORY);
                else if (QUERY_FLAG(op, FLAG_STARTEQUIP)
                        || QUERY_FLAG(op, FLAG_NO_DROP)
                        || op->type == RUNE
                        || op->type == TRAP
                        || QUERY_FLAG(op, FLAG_IS_A_TEMPLATE))
                    object_free_drop_inventory(op);
                else {
                    object *part;

                    /* If it's a multi-tile object, scatter dropped items randomly */
                    if (ob->more) {
                        int partcount = 0;
                        /* Get the number of non-head parts */
                        for (part = ob; part; part = part->more) {
                            partcount++;
                        }
                        /* Select a random part */
                        partcount = RANDOM()%partcount;
                        for (part = ob; partcount > 0; partcount--) {
                            part = part->more;
                        }
                    } else {
                        part = ob;
                    }

                    if (QUERY_FLAG(op, FLAG_ALIVE)) {
                        object_insert_to_free_spot_or_free(op, part->map, part->x, part->y, 0, SIZEOFFREE, NULL);
                    } else {
                        int f = 0;
                        if (flags & FREE_OBJ_DROP_ABOVE_FLOOR)
                            f = INS_ABOVE_FLOOR_ONLY;
                        object_insert_in_map_at(op, part->map, NULL, f, part->x, part->y); /* Insert in same map as the envir */
                    }
                }
            } FOR_INV_FINISH();
        }
    }

    if (ob->more != NULL) {
        object_free(ob->more, flags);
        ob->more = NULL;
    }

    /* Remove object from the active list */
    ob->speed = 0;
    object_update_speed(ob);

    SET_FLAG(ob, FLAG_FREED);
    ob->count = 0;

    /* Remove this object from the list of used objects */
    if (ob->prev == NULL) {
        objects = ob->next;
        if (objects != NULL)
            objects->prev = NULL;
    } else {
        ob->prev->next = ob->next;
        if (ob->next != NULL)
            ob->next->prev = ob->prev;
    }

    if (ob->artifact != NULL) FREE_AND_CLEAR_STR(ob->artifact);
    if (ob->name != NULL) FREE_AND_CLEAR_STR(ob->name);
    if (ob->name_pl != NULL) FREE_AND_CLEAR_STR(ob->name_pl);
    if (ob->title != NULL) FREE_AND_CLEAR_STR(ob->title);
    if (ob->race != NULL) FREE_AND_CLEAR_STR(ob->race);
    if (ob->slaying != NULL) FREE_AND_CLEAR_STR(ob->slaying);
    if (ob->skill != NULL) FREE_AND_CLEAR_STR(ob->skill);
    if (ob->lore != NULL) FREE_AND_CLEAR_STR(ob->lore);
    if (ob->msg != NULL) FREE_AND_CLEAR_STR(ob->msg);
    if (ob->materialname != NULL) FREE_AND_CLEAR_STR(ob->materialname);
    if (ob->spell_tags) FREE_AND_CLEAR(ob->spell_tags);

    /* Why aren't events freed? */
    object_free_key_values(ob);

    free_dialog_information(ob);

    /* Test whether archetype is a temporary one, and if so look whether it should be trashed. */
    if (ob->arch && ob->arch->reference_count > 0) {
        if (--ob->arch->reference_count == 0) {
            free_arch(ob->arch);
        }
    }

#ifdef MEMORY_DEBUG
    free(ob);
#else
    /* Now link it with the free_objects list: */
    ob->prev = NULL;
    ob->next = free_objects;
    if (free_objects != NULL)
        free_objects->prev = ob;
    free_objects = ob;
    nroffreeobjects++;
#endif
}

/**
 * Objects statistics.
 *
 * @return
 * number of objects on the list of free objects.
 */
int object_count_free(void) {
    int i = 0;
    object *tmp = free_objects;

    while (tmp != NULL)
        tmp = tmp->next,
        i++;
    return i;
}

/**
 * Object statistics.
 *
 * @return
 * number of objects on the list of used objects.
 */
int object_count_used(void) {
    int i = 0;
    object *tmp = objects;

    while (tmp != NULL)
        tmp = tmp->next,
        i++;
    return i;
}

/**
 * Objects statistics.
 *
 * @return
 * number of objects on the list of active objects.
 */
int object_count_active(void) {
    int i = 0;
    object *tmp = active_objects;

    while (tmp != NULL)
        tmp = tmp->active_next,
        i++;
    return i;
}

/**
 * Recursively (outwards) subtracts a number from the
 * weight of an object (and what is carried by it's environment(s)).
 *
 * Takes into account the container's weight reduction.
 *
 * @param op
 * object to which weight is substracted.
 * @param weight
 * weight to remove.
 *
 * @todo
 * check if not mergeable with object_add_weight().
 */
void object_sub_weight(object *op, signed long weight) {
    while (op != NULL) {
        if (op->type == CONTAINER) {
            weight = (signed long)(weight*(100-op->stats.Str)/100);
        }
        op->carrying -= weight;
        op = op->env;
    }
}

/**
 * This function removes the object op from the linked list of objects
 * which it is currently tied to.  When this function is done, the
 * object will have no environment.  If the object previously had an
 * environment, the x and y coordinates will be updated to
 * the previous environment.
 *
 * Will inform the client of the removal if needed.
 *
 * @param op
 * object to remove. Must not be removed yet, else abort() is called.
 *
 * @todo
 * this function is a piece of overbloated crap or at lest
 * look like need cleanup it does to much different things.
 */
void object_remove(object *op) {
    object *last = NULL;
    object *otmp;
    tag_t tag;
    int check_walk_off;
    mapstruct *m;
    int16_t x, y;

    if (QUERY_FLAG(op, FLAG_REMOVED)) {
        StringBuffer *sb;
        char *diff;

        sb = stringbuffer_new();
        object_dump(op, sb);
        diff = stringbuffer_finish(sb);
        LOG(llevError, "Trying to remove removed object.\n%s\n", diff);
        free(diff);
        abort();
    }
    if (op->more != NULL)
        object_remove(op->more);

    SET_FLAG(op, FLAG_REMOVED);

    /*
     * In this case, the object to be removed is in someones
     * inventory.
     */
    /* TODO try to call a generic inventory weight adjusting function like object_sub_weight */
    if (op->env != NULL) {
        player *pl = NULL;

        if (op->nrof)
            object_sub_weight(op->env, op->weight*op->nrof);
        else
            object_sub_weight(op->env, op->weight+op->carrying);

        /* Update in two cases: item is in a player, or in a container the player is looking into. */
        if (op->env->contr != NULL && op->head == NULL) {
            pl = op->env->contr;
        } else if (op->env->type == CONTAINER && QUERY_FLAG(op->env, FLAG_APPLIED)) {

            if (op->env->env && op->env->env->contr)
                /* Container is in player's inventory. */
                pl = op->env->env->contr;
            else if (op->env->map) {
                /* Container on map, look above for player. */
                object *above = op->env->above;

                while (above && !above->contr)
                    above = above->above;
                if (above)
                    pl = above->contr;
            }
        }

        /* NO_FIX_PLAYER is set when a great many changes are being
         * made to players inventory.  If set, avoiding the call
         * to save cpu time.
         */
        otmp = object_get_player_container(op->env);
        if (otmp != NULL
        && otmp->contr
        && !QUERY_FLAG(otmp, FLAG_NO_FIX_PLAYER))
            fix_object(otmp);

        if (op->above != NULL)
            op->above->below = op->below;
        else
            op->env->inv = op->below;

        if (op->below != NULL)
            op->below->above = op->above;

        /* we set up values so that it could be inserted into
         * the map, but we don't actually do that - it is up
         * to the caller to decide what we want to do.
         */
        op->x = op->env->x;
        op->y = op->env->y;
        op->ox = op->x;
        op->oy = op->y;
        op->map = op->env->map;
        op->above = NULL;
        op->below = NULL;
        /* send the delitem before resetting env, so container's contents be may
         * refreshed */
        if (LOOK_OBJ(op) && pl != NULL)
            esrv_del_item(pl, op);
        op->env = NULL;
        return;
    }

    /* If we get here, we are removing it from a map */
    if (op->map == NULL)
        return;

    if (op->contr != NULL && !op->contr->hidden)
        op->map->players--;

    x = op->x;
    y = op->y;
    m = get_map_from_coord(op->map, &x, &y);

    if (!m) {
        LOG(llevError, "object_remove called when object was on map but appears to not be within valid coordinates? %s (%d,%d)\n", op->map->path, op->x, op->y);
        abort();
    }
    if (op->map != m) {
        LOG(llevError, "object_remove: Object not really on map it claimed to be on? %s != %s, %d,%d != %d,%d\n", op->map->path, m->path, op->x, op->y, x, y);
    }

    /* link the object above us */
    if (op->above)
        op->above->below = op->below;
    else
        SET_MAP_TOP(m, x, y, op->below); /* we were top, set new top */

    /* Relink the object below us, if there is one */
    if (op->below) {
        op->below->above = op->above;
    } else {
        /* Nothing below, which means we need to relink map object for this space
         * use translated coordinates in case some oddness with map tiling is
         * evident
         */
        /*TODO is this check really needed?*/
        if (GET_MAP_OB(m, x, y) != op) {
            StringBuffer *sb;
            char *diff;

            sb = stringbuffer_new();
            object_dump(op, sb);
            diff = stringbuffer_finish(sb);
            LOG(llevError, "object_remove: GET_MAP_OB on %s does not return object to be removed even though it appears to be on the bottom?\n%s\n", m->path, diff);
            free(diff);

            sb = stringbuffer_new();
            object_dump(GET_MAP_OB(m, x, y), sb);
            diff = stringbuffer_finish(sb);
            LOG(llevError, "%s\n", diff);
            free(diff);
        }
        SET_MAP_OB(m, x, y, op->above);  /* goes on above it. */
    }
    op->above = NULL;
    op->below = NULL;

    if (op->map->in_memory == MAP_SAVING)
        return;

    tag = op->count;
    check_walk_off = !QUERY_FLAG(op, FLAG_NO_APPLY);
    FOR_MAP_PREPARE(m, x, y, tmp) {
        /* No point updating the players look faces if he is the object
         * being removed.
         */

        if (tmp->type == PLAYER && tmp != op) {
            /* If a container that the player is currently using somehow gets
             * removed (most likely destroyed), update the player view
             * appropriately.
            */
            if (tmp->container == op) {
                CLEAR_FLAG(op, FLAG_APPLIED);
                tmp->container = NULL;
            }
            tmp->contr->socket.update_look = 1;
        }
        /* See if player moving off should effect something */
        if (check_walk_off
        && ((op->move_type&tmp->move_off) && (op->move_type&~tmp->move_off&~tmp->move_block) == 0)) {
            ob_move_on(tmp, op, NULL);
            if (object_was_destroyed(op, tag)) {
                LOG(llevError, "BUG: object_remove(): name %s, archname %s destroyed leaving object\n", tmp->name, tmp->arch->name);
            }
        }

        /* Eneq(@csd.uu.se): Fixed this to skip tmp->above=tmp */
        if (tmp->above == tmp)
            tmp->above = NULL;
        last = tmp;
    } FOR_MAP_FINISH();
    /* last == NULL or there are no objects on this space */
    if (last == NULL) {
        /* set P_NEED_UPDATE, otherwise update_position will complain.  In theory,
        * we could preserve the flags (GET_MAP_FLAGS), but update_position figures
        * those out anyways, and if there are any flags set right now, they won't
        * be correct anyways.
        */
        SET_MAP_FLAGS(op->map, op->x, op->y,  P_NEED_UPDATE);
        update_position(op->map, op->x, op->y);
    } else
        object_update(last, UP_OBJ_REMOVE);

    if (QUERY_FLAG(op, FLAG_BLOCKSVIEW) || (op->glow_radius != 0))
        update_all_los(op->map, op->x, op->y);
}

/**
 * This function goes through all objects below and including top, and
 * merges op to the first matching object.
 *
 * Will correctly send updated objects to client if needed.
 *
 * @param op
 * object to merge.
 * @param top
 * from which item to merge. If NULL, it is calculated.
 * @return
 * pointer to object if it succeded in the merge, otherwise NULL
 */
object *object_merge(object *op, object *top) {
    if (!op->nrof)
        return NULL;

    if (top == NULL)
        for (top = op; top != NULL && top->above != NULL; top = top->above)
            ;
    FOR_OB_AND_BELOW_PREPARE(top) {
        if (top == op)
            continue;
        if (object_can_merge(op, top)) {
            object_increase_nrof(top, op->nrof);
            /*
             * Previous behavior set weight to zero here.
             * This, however, caused the object_sub_weight
             * call in object_remove to subtract zero weight
             * when removing the object. Thus, until inventory
             * weight is next recalculated, the object merged
             * into another pile added weight in object_increase_nrof
             * but did not remove the weight from the original
             * instance of itself in object_remove, essentially
             * counting for double weight for several minutes.
             *
             * SilverNexus 2014-05-27
             */
            object_remove(op);
            object_free(op, FREE_OBJ_FREE_INVENTORY | FREE_OBJ_NO_DESTROY_CALLBACK);
            return top;
        }
    } FOR_OB_AND_BELOW_FINISH();
    return NULL;
}

/**
 * Same as object_insert_in_map() except it handle separate coordinates and do a clean
 * job preparing multi-part monsters.
 *
 * @param op
 * object to insert.
 * @param m
 * map to insert into.
 * @param originator
 * what caused op to be inserted.
 * @param flag
 * Combination of @ref INS_xxx "INS_xxx" values.
 * @param x
 * @param y
 * coordinates to insert at.
 */
object *object_insert_in_map_at(object *op, mapstruct *m, object *originator, int flag, int x, int y) {
    object *tmp;

    op = HEAD(op);
    for (tmp = op; tmp; tmp = tmp->more) {
        tmp->x = x+tmp->arch->clone.x;
        tmp->y = y+tmp->arch->clone.y;
        tmp->map = m;
    }
    return object_insert_in_map(op, m, originator, flag);
}

/**
 * This sees if there are any objects on the space that can
 * merge with op.  Note that op does not need to actually
 * be inserted on the map (when called from object_insert_in_map,
 * it won't be), but op->map should be set correctly.
 *
 * Note that even if we find a match on the space, we keep progressing
 * looking for more.  This is because op->range is set to 0 in
 * explosion, so what may not have been mergable now is.
 *
 * @param op
 * object to try to merge into.
 *
 * @param x
 * @param y
 * coordinates to look at for merging.
 */
void object_merge_spell(object *op, int16_t x, int16_t y) {
    int i;

    /* We try to do some merging of spell objects - if something has same owner,
     * is same type of spell, and going in the same direction, it is somewhat
     * mergable.
     *
     * If the spell object has an other_arch, don't merge - when the spell
     * does something, like explodes, it will use this other_arch, and
     * if we merge, there is no easy way to make the correct values be
     * set on this new object (values should be doubled, tripled, etc.)
     *
     * We also care about speed - only process objects that will not be
     * active this tick.  Without this, the results are incorrect - think
     * of a case where tmp would normally get processed this tick, but
     * get merges with op, which does not get processed.
     */
    FOR_MAP_PREPARE(op->map, x, y, tmp) {
        if (op->type == tmp->type
        && op->subtype == tmp->subtype
        && op->direction == tmp->direction
        && op->owner == tmp->owner && op->ownercount == tmp->ownercount
        && op->range == tmp->range
        && op->stats.wc == tmp->stats.wc
        && op->level == tmp->level
        && op->attacktype == tmp->attacktype
        && op->speed == tmp->speed
        && !tmp->other_arch
        && (tmp->speed_left+tmp->speed) < 0.0
        && op != tmp) {
            /* Quick test - if one or the other objects already have hash tables
             * set up, and that hash bucket contains a value that doesn't
             * match what we want to set it up, we won't be able to merge.
             * Note that these two if statements are the same, except
             * for which object they are checking against.  They could
             * be merged, but the line wrapping would be large enough
             * that IMO it would become difficult to read the different clauses
             * so its cleaner just to do 2 statements - MSW
             */
            if (op->spell_tags
            && !OB_SPELL_TAG_MATCH(op, (tag_t)tmp->stats.maxhp)
            && OB_SPELL_TAG_HASH(op, tmp->stats.maxhp) != 0)
                continue;

            if (tmp->spell_tags
            && !OB_SPELL_TAG_MATCH(tmp, (tag_t)op->stats.maxhp)
            && OB_SPELL_TAG_HASH(tmp, op->stats.maxhp) != 0)
                continue;

            /* If we merge, the data from tmp->spell_tags gets copied into op.
             * so we need to make sure that slot isn't filled up.
             */
            if (tmp->spell_tags
            && !OB_SPELL_TAG_MATCH(tmp, (tag_t)tmp->stats.maxhp)
            && OB_SPELL_TAG_HASH(tmp, tmp->stats.maxhp) != 0)
                continue;

            /* If both objects have spell_tags, we need to see if there are conflicting
             * values - if there are, we won't be able to merge then.
             */
            if (tmp->spell_tags && op->spell_tags) {
                int need_copy = 0;

                for (i = 0; i < SPELL_TAG_SIZE; i++) {
                    /* If the two tag values in the hash are set, but are
                     * not set to the same value, then these objects
                     * can not be merged.
                     */
                    if (op->spell_tags[i] && tmp->spell_tags[i]
                    && op->spell_tags[i] != tmp->spell_tags[i]) {
                        statistics.spell_hash_full++;
                        break;
                    }
                    /* If one tag is set and the other is not, that is
                     * fine, but we have to note that we need to copy
                     * the data in that case.
                     */
                    if ((!op->spell_tags[i] && tmp->spell_tags[i])
                    || (op->spell_tags[i] && !tmp->spell_tags[i])) {
                        need_copy = 1;
                    }
                }
                /* If we did not get through entire array, it means
                 * we got a conflicting hash, and so we won't be
                 * able to merge these - just continue processing
                 * object on this space.
                 */
                if (i <= SPELL_TAG_SIZE)
                    continue;

                /* Ok - everything checked out - we should be able to
                 * merge tmp in op.  So lets copy the tag data if
                 * needed.  Note that this is a selective copy, as
                 * we don't want to clear values that may be set in op.
                 */
                if (need_copy) {
                    for (i = 0; i < SPELL_TAG_SIZE; i++)
                        if (!op->spell_tags[i]
                        && tmp->spell_tags[i]
                        && tmp->spell_tags[i] != (tag_t)op->stats.maxhp)
                            op->spell_tags[i] = tmp->spell_tags[i];
                }
                FREE_AND_CLEAR(tmp->spell_tags);
            }

            /* if tmp has a spell_tags table, copy it to op and free tmps */
            if (tmp->spell_tags && !op->spell_tags) {
                op->spell_tags = tmp->spell_tags;
                tmp->spell_tags = NULL;

                /* We don't need to keep a copy of our maxhp value
                 * in the copied over value
                */
                if (OB_SPELL_TAG_MATCH(op, (tag_t)op->stats.maxhp))
                    OB_SPELL_TAG_HASH(op, op->stats.maxhp) = 0;
            }

            /* For spells to work correctly, we need to record what spell
             * tags we've merged in with this effect.  This is used
             * in ok_to_put_more() to see if a spell effect is already on
             * the space.
             */
            if (op->stats.maxhp != tmp->stats.maxhp) {
#ifdef OBJECT_DEBUG
                /* This if statement should never happen - the logic above should
                 * have prevented it.  It is a problem, because by now its possible
                 * we've destroyed the spell_tags in tmp, so we can't really
                 * just bail out.
                 */

                if (op->spell_tags
                && OB_SPELL_TAG_HASH(op, tmp->stats.maxhp) != 0
                && !OB_SPELL_TAG_MATCH(op, tmp->stats.maxhp)) {
                    LOG(llevError, "object_insert_in_map: Got non matching spell tags: %d != %d\n", OB_SPELL_TAG_HASH(op, tmp->stats.maxhp), tmp->stats.maxhp);
                }
#endif
                if (!op->spell_tags)
                    op->spell_tags = calloc(SPELL_TAG_SIZE, sizeof(tag_t));

                OB_SPELL_TAG_HASH(op, tmp->stats.maxhp) = tmp->stats.maxhp;
            }

            statistics.spell_merges++;
            op->speed_left = MAX(op->speed_left, tmp->speed_left);

            if (tmp->duration != op->duration) {
                /* We need to use tmp_dam here because otherwise the
                 * calculations can overflow the size of stats.dam.
                 */
                int tmp_dam = tmp->stats.dam*(tmp->duration+1)+
                              op->stats.dam*(op->duration+1);

                op->duration = MAX(op->duration, tmp->duration);
                tmp_dam /= op->duration+1;
                op->stats.dam = tmp_dam+1;
            } else {
                /* in this case, duration is the same, so simply adding
                 * up damage works.
                 */
                op->stats.dam += tmp->stats.dam;
            }

            object_remove(tmp);
            object_free_drop_inventory(tmp);
        }
    } FOR_MAP_FINISH();
}

static object *find_insert_pos(object *op, const int flag) {
    object *floor = NULL;
    /*
     * If there are multiple objects on this space, we do some trickier handling.
     * We've already dealt with merging if appropriate.
     * Generally, we want to put the new object on top. But if
     * flag contains INS_ABOVE_FLOOR_ONLY, once we find the last
     * floor, we want to insert above that and no further.
     * Also, if there are spell objects on this space, we stop processing
     * once we get to them.  This reduces the need to traverse over all of
     * them when adding another one - this saves quite a bit of cpu time
     * when lots of spells are cast in one area.  Currently, it is presumed
     * that flying non pickable objects are spell objects.
     */
    if (flag&INS_ON_TOP) {
        return GET_MAP_TOP(op->map, op->x, op->y);
    }
    object *last = NULL;
    FOR_MAP_PREPARE(op->map, op->x, op->y, tmp) {
        if (QUERY_FLAG(tmp, FLAG_IS_FLOOR)
        || QUERY_FLAG(tmp, FLAG_OVERLAY_FLOOR))
            floor = tmp;

        if (QUERY_FLAG(tmp, FLAG_NO_PICK)
        && (tmp->move_type&(MOVE_FLY_LOW|MOVE_FLY_HIGH))
        && !QUERY_FLAG(tmp, FLAG_IS_FLOOR)) {
            /* We insert above tmp, so we want this object below this */
            break;
        }
        last = tmp;
    } FOR_MAP_FINISH();
    if (flag&INS_ABOVE_FLOOR_ONLY)
        return floor;
    return last;
}

/**
 * This function inserts the object in the two-way linked list
 * which represents what is on a map.
 *
 * It will update player count if the op is a player.
 *
 * Player ground window will be updated if needed.
 *
 * @param op
 * object to insert. Must be removed. Its coordinates must be valid for the map.
 * @param m
 * map to insert into. Must not be NULL.
 * @param originator
 * player, monster or other object that caused 'op' to be inserted
 * into 'm'.  May be NULL.
 * @param flag
 * bitmask about special things to do (or not do) when this
 * function is called. See the object.h file for the @ref INS_xxx "INS_xxx" values.
 * Passing 0 for flag gives proper default values, so flag really only needs
 * to be set if special handling is needed.
 * @return
 * @li new object if 'op' was merged with other object.
 * @li NULL if 'op' was destroyed
 * @li just 'op' otherwise
 *
 * @todo
 * this function is a mess, and should be cleaned.
 */
object *object_insert_in_map(object *op, mapstruct *m, object *originator, int flag) {
    object *tmp, *top, *floor = NULL;
    int16_t x, y;

    if (QUERY_FLAG(op, FLAG_FREED)) {
        LOG(llevError, "Trying to insert freed object!\n");
        return NULL;
    }
    if (m == NULL) {
        StringBuffer *sb;
        char *diff;

        sb = stringbuffer_new();
        object_dump(op, sb);
        diff = stringbuffer_finish(sb);
        LOG(llevError, "Trying to insert in null-map!\n%s\n", diff);
        free(diff);
        return op;
    }
    if (out_of_map(m, op->x, op->y)) {
        StringBuffer *sb;
        char *diff;

        sb = stringbuffer_new();
        object_dump(op, sb);
        diff = stringbuffer_finish(sb);
        LOG(llevError, "Trying to insert object outside the map.\n%s\n", diff);
        free(diff);
#ifdef MANY_CORES
        /* Better to catch this here, as otherwise the next use of this object
         * is likely to cause a crash.  Better to find out where it is getting
         * improperly inserted.
         */
        abort();
#endif
        return op;
    }
    if (!QUERY_FLAG(op, FLAG_REMOVED)) {
        StringBuffer *sb;
        char *diff;

        sb = stringbuffer_new();
        object_dump(op, sb);
        diff = stringbuffer_finish(sb);
        LOG(llevError, "Trying to insert (map) inserted object.\n%s\n", diff);
        free(diff);
        return op;
    }
    if (op->more != NULL) {
        /* The part may be on a different map. */

        object *more = op->more;

        /* We really need the caller to normalize coordinates - if
         * we set the map, that doesn't work if the location is within
         * a map and this is straddling an edge.  So only if coordinate
         * is clear wrong do we normalize it.
         */
        if (OUT_OF_REAL_MAP(more->map, more->x, more->y)) {
            /* Debugging information so you can see the last coordinates this object had */
            more->ox = more->x;
            more->oy = more->y;
            more->map = get_map_from_coord(more->map, &more->x, &more->y);
        } else if (!more->map) {
            /* For backwards compatibility - when not dealing with tiled maps,
            * more->map should always point to the parent.
            */
            more->map = m;
        }

        if (object_insert_in_map(more, more->map, originator, flag) == NULL) {
            if (!op->head)
                LOG(llevError, "BUG: object_insert_in_map(): inserting op->more killed op\n");
            return NULL;
        }
    }
    CLEAR_FLAG(op, FLAG_REMOVED);

    /* Debugging information so you can see the last coordinates this object had */
    op->ox = op->x;
    op->oy = op->y;
    x = op->x;
    y = op->y;
    op->map = get_map_from_coord(m, &x, &y);

    /* this has to be done after we translate the coordinates. */
    if (op->nrof
    && !(flag&INS_NO_MERGE)
    && op->type != SPELL_EFFECT) {
        FOR_MAP_PREPARE(op->map, x, y, tmp) {
            if (object_can_merge(op, tmp)) {
                op->nrof += tmp->nrof;
                object_remove(tmp);
                object_free(tmp, FREE_OBJ_FREE_INVENTORY | FREE_OBJ_NO_DESTROY_CALLBACK);
            }
        } FOR_MAP_FINISH();
    } else if (op->type == SPELL_EFFECT
    && !op->range
    && !op->other_arch
    && (op->speed_left+op->speed) < 0.0) {
        object_merge_spell(op, x, y);
    }

    /* Ideally, the caller figures this out.  However, it complicates a lot
     * of areas of callers (eg, anything that uses object_find_free_spot() would now
     * need extra work
     */
    if (op->map != m) {
        /* coordinates should not change unless map also changes */
        op->x = x;
        op->y = y;
    }

    if (op->type != LAMP)
        /* lamps use the FLAG_APPLIED to keep the light/unlit status, so don't reset it.
         Other objects just get unapplied, since the container "drops" them. */
        CLEAR_FLAG(op, FLAG_APPLIED);
    CLEAR_FLAG(op, FLAG_INV_LOCKED);
    if (!QUERY_FLAG(op, FLAG_ALIVE))
        CLEAR_FLAG(op, FLAG_NO_STEAL);

    /* In many places, a player is passed as the originator, which
     * is fine.  However, if the player is on a transport, they are not
     * actually on the map, so we can't use them for the linked pointers,
     * nor should the walk on function below use them either.
     */
    if (originator && originator->contr && originator->contr->transport)
        originator = originator->contr->transport;

    if (flag&INS_BELOW_ORIGINATOR) {
        if (originator->map != op->map
        || originator->x != op->x
        || originator->y != op->y) {
            LOG(llevError, "object_insert_in_map called with INS_BELOW_ORIGINATOR when originator not on same space!\n");
            abort();
        }
        op->above = originator;
        op->below = originator->below;
        if (op->below)
            op->below->above = op;
        else
            SET_MAP_OB(op->map, op->x, op->y, op);
        /* since *below *originator, no need to update top */
        originator->below = op;
    } else {
        /* Top is the object that our object (op) is going to get inserted above. */
        top = find_insert_pos(op, flag);

        /* First object on this space */
        if (!top) {
            op->above = GET_MAP_OB(op->map, op->x, op->y);
            if (op->above)
                op->above->below = op;
            op->below = NULL;
            SET_MAP_OB(op->map, op->x, op->y, op);
        } else { /* get inserted into the stack above top */
            op->above = top->above;
            if (op->above)
                op->above->below = op;
            op->below = top;
            top->above = op;
        }
        if (op->above == NULL)
            SET_MAP_TOP(op->map, op->x, op->y, op);
    } /* else not INS_BELOW_ORIGINATOR */

    if (!(flag&INS_MAP_LOAD)) {
        if (op->type == PLAYER)
            op->contr->do_los = 1;

        /* If we have a floor, we know the player, if any, will be above
         * it, so save a few ticks and start from there.
         */
        tmp = floor ? floor : GET_MAP_OB(op->map, op->x, op->y);
        FOR_OB_AND_ABOVE_PREPARE(tmp)
            if (tmp->type == PLAYER)
                tmp->contr->socket.update_look = 1;
        FOR_OB_AND_ABOVE_FINISH();

        /* If this object glows, it may affect lighting conditions that are
         * visible to others on this map.  But update_all_los is really
         * an inefficient way to do this, as it means los for all players
         * on the map will get recalculated.  The players could very well
         * be far away from this change and not affected in any way -
         * this should get redone to only look for players within range,
         * or just updating the P_NEED_UPDATE for spaces within this area
         * of effect may be sufficient.
         */
        if (MAP_DARKNESS(op->map) && (op->glow_radius != 0))
            update_all_los(op->map, op->x, op->y);

        if (op->contr && !op->contr->hidden)
            op->map->players++;
    }

    /* updates flags (blocked, alive, no magic, etc) for this map space */
    object_update(op, UP_OBJ_INSERT);

    /* Don't know if moving this to the end will break anything.  However,
     * we want to have update_look set above before calling this.
     *
     * object_check_move_on() must be after this because code called from
     * object_check_move_on() depends on correct map flags (so functions like
     * blocked() and wall() work properly), and these flags are updated by
     * object_update().
     */

    /* if this is not the head or flag has been passed, don't check walk on status */

    if (!(flag&INS_NO_WALK_ON) && !op->head) {
        if (object_check_move_on(op, originator))
            return NULL;

        /* If we are a multi part object, lets work our way through the check
         * walk on's.
         */
        for (tmp = op->more; tmp != NULL; tmp = tmp->more)
            if (object_check_move_on(tmp, originator))
                return NULL;
    }
    return op;
}

/**
 * This function inserts an object of a specified archetype in the map, but if it
 * finds objects of its own type, it'll remove them first.
 *
 * @param arch_string
 * object's archetype to insert.
 * @param op
 * object to insert it under:  supplies x and the map.
 */
void object_replace_insert_in_map(const char *arch_string, object *op) {
    object *tmp1;
    archetype *at;

    /* first search for itself and remove any old instances */
    FOR_MAP_PREPARE(op->map, op->x, op->y, tmp) {
        if (!strcmp(tmp->arch->name, arch_string)) { /* same archetype */
            object_remove(tmp);
            object_free_drop_inventory(tmp);
        }
    } FOR_MAP_FINISH();

    at = find_archetype(arch_string);
    if (at == NULL) {
        return;
    }
    tmp1 = arch_to_object(at);
    object_insert_in_map_at(tmp1, op->map, op, INS_BELOW_ORIGINATOR, op->x, op->y);
}

/**
 * object_split(ob,nr) splits up ob into two parts.  The part which
 * is returned contains nr objects, and the remaining parts contains
 * the rest (or is removed and freed if that number is 0).
 * On failure, NULL is returned, and the reason LOG()ed.
 *
 * This function will send an update to the client if the remaining object
 * is in a player inventory.
 *
 * @param orig_ob
 * object from which to split.
 * @param nr
 * number of elements to split.
 * @param err
 * buffer that will contain failure reason if NULL is returned. Can be NULL.
 * @param size
 * err's size
 * @return
 * split object, or NULL on failure.
 */
object *object_split(object *orig_ob, uint32_t nr, char *err, size_t size) {
    object *newob;

    if (MAX(1, orig_ob->nrof) < nr) {
        /* If err is set, the caller knows that nr can be wrong (player trying to drop items), thus don't log that. */
        if (err)
            snprintf(err, size, "There are only %u %ss.", NROF(orig_ob), orig_ob->name);
        else
            LOG(llevDebug, "There are only %u %ss.\n", NROF(orig_ob), orig_ob->name);
        return NULL;
    }
    newob = object_create_clone(orig_ob);
    if (orig_ob->nrof == 0) {
        if (!QUERY_FLAG(orig_ob, FLAG_REMOVED)) {
            object_remove(orig_ob);
        }
        object_free(orig_ob, FREE_OBJ_FREE_INVENTORY);
    } else {
        newob->nrof = nr;
        object_decrease_nrof(orig_ob, nr);
    }

    return newob;
}

/**
 * Decreases a specified number from
 * the amount of an object.  If the amount reaches 0, the object
 * is subsequently removed and freed.
 *
 * This function will send an update to client if op is in a player inventory.
 *
 * @param op
 * object to decrease.
 * @param i
 * number to remove.
 * @return
 * 'op' if something is left, NULL if the amount reached 0.
 */
object *object_decrease_nrof(object *op, uint32_t i) {
    object *tmp;

    if (i == 0)   /* objects with op->nrof require this check */
        return op;

    if (i > op->nrof)
        i = op->nrof;

    if (QUERY_FLAG(op, FLAG_REMOVED)) {
        op->nrof -= i;
    } else if (op->env != NULL) {
        if (i < op->nrof) {
            player *pl;
            /* is this object in the players inventory, or sub container
             * therein?
             */
            tmp = object_get_player_container(op->env);
            /* nope.  Is this a container the player has opened?
             * If so, set tmp to that player.
             * IMO, searching through all the players will mostly
             * likely be quicker than following op->env to the map,
             * and then searching the map for a player.
             */
            if (!tmp) {
                for (pl = first_player; pl; pl = pl->next)
                    if (pl->ob->container == op->env)
                        break;
                if (pl)
                    tmp = pl->ob;
                else
                    tmp = NULL;
            }

            /* Because of weight reduction by container and integer arithmetic,
             * there is no guarantee the rounded weight of combined items will be
             * the same as the sum of rounded weights.
             * Therefore just remove the current weight, and add the new.
             * Same adjustment done in object_increase_nrof().
             */
            object_sub_weight(op->env, op->weight * op->nrof);
            op->nrof -= i;
            object_add_weight(op->env, op->weight * op->nrof);
            if (tmp) {
                esrv_update_item(UPD_NROF, tmp, op);
                esrv_update_item(UPD_WEIGHT, tmp, op->env);
                fix_object(tmp);
            }
        } else {
            object_remove(op);
            op->nrof = 0;
        }
    } else {
        /* On a map. */
        if (i < op->nrof) {
            op->nrof -= i;

            FOR_MAP_PREPARE(op->map, op->x, op->y, pl)
                if (pl->contr) {
                    pl->contr->socket.update_look = 1;
                    break;
                }
            FOR_MAP_FINISH();
        } else {
            object_remove(op);
            op->nrof = 0;
        }
    }

    if (op->nrof) {
        return op;
    } else {
        object_free_drop_inventory(op);
        return NULL;
    }
}

/**
 * Increase the count of an object.
 *
 * This function will send an update to client if needed.
 *
 * @param op
 * object to increase.
 * @param i
 * number to add.
 */
static void object_increase_nrof(object *op, uint32_t i) {
    object *tmp;

    if (i == 0)   /* objects with op->nrof require this check */
        return;

    if (QUERY_FLAG(op, FLAG_REMOVED)) {
        op->nrof += i;
    } else if (op->env != NULL) {
        player *pl;
        /* is this object in the players inventory, or sub container
         * therein?
         */
        tmp = object_get_player_container(op->env);
        /* nope.  Is this a container the player has opened?
         * If so, set tmp to that player.
         * IMO, searching through all the players will mostly
         * likely be quicker than following op->env to the map,
         * and then searching the map for a player.
         */
        if (!tmp) {
            for (pl = first_player; pl; pl = pl->next)
                if (pl->ob->container == op->env)
                    break;
            if (pl)
                tmp = pl->ob;
            else
                tmp = NULL;
        }

        /* Because of weight reduction by container and integer arithmetic,
         * there is no guarantee the rounded weight of combined items will be
         * the same as the sum of rounded weights.
         * Therefore just remove the current weight, and add the new.
         * Same adjustment done in object_decrease_nrof().
         */
        object_sub_weight(op->env, op->weight * op->nrof);
        op->nrof += i;
        object_add_weight(op->env, op->weight * op->nrof);
        if (tmp) {
            esrv_update_item(UPD_NROF, tmp, op);
            // Why don't we need to update weight of op->env here?
        }
    } else {
        /* On a map. */
        op->nrof += i;

        FOR_MAP_PREPARE(op->map, op->x, op->y, pl)
            if (pl->contr) {
                pl->contr->socket.update_look = 1;
                break;
            }
        FOR_MAP_FINISH();
    }
}

/**
 * object_add_weight(object, weight) adds the specified weight to an object,
 * and also updates how much the environment(s) is/are carrying.
 *
 * Takes container weight reduction into account.
 *
 * @param op
 * object to which we add weight.
 * @param weight
 * weight to add.
 *
 * @todo
 * check if mergeable with object_sub_weight().
 */
void object_add_weight(object *op, signed long weight) {
    while (op != NULL) {
        if (op->type == CONTAINER) {
            weight = (signed long)(weight*(100-op->stats.Str)/100);
        }
        op->carrying += weight;
        op = op->env;
    }
}

/**
 * This function inserts the object op in the linked list
 * inside the object environment.
 *
 * It will send to client where is a player.
 *
 * @param op
 * object to insert. Must be removed and not NULL. Must not be multipart.
 * May become invalid after return, so use return value of the function.
 * @param where
 * object to insert into. Must not be NULL. Should be the head part.
 * @return
 * pointer to inserted item, which will be different than op if object was merged.
 */
object *object_insert_in_ob(object *op, object *where) {
    object *otmp;

    if (!QUERY_FLAG(op, FLAG_REMOVED)) {
        StringBuffer *sb;
        char *diff;

        sb = stringbuffer_new();
        object_dump(op, sb);
        diff = stringbuffer_finish(sb);
        LOG(llevError, "Trying to insert (ob) inserted object.\n%s\n", diff);
        free(diff);
        return op;
    }

    if (where == NULL) {
        StringBuffer *sb;
        char *diff;

        sb = stringbuffer_new();
        object_dump(op, sb);
        diff = stringbuffer_finish(sb);
        LOG(llevError, "Trying to put object in NULL.\n%s\n", diff);
        free(diff);
        return op;
    }
    if (where->head) {
        LOG(llevDebug, "Warning: Tried to insert object wrong part of multipart object.\n");
    }
    where = HEAD(where);
    if (op->more) {
        LOG(llevError, "Tried to insert multipart object %s (%u)\n", op->name, op->count);
        return op;
    }
    CLEAR_FLAG(op, FLAG_OBJ_ORIGINAL);
    CLEAR_FLAG(op, FLAG_REMOVED);
    if (op->nrof) {
        FOR_INV_PREPARE(where, tmp)
            if (object_can_merge(tmp, op)) {
                /* return the original object and remove inserted object
                 * (client needs the original object) */
                object_increase_nrof(tmp, op->nrof);
                SET_FLAG(op, FLAG_REMOVED);
                object_free(op, FREE_OBJ_FREE_INVENTORY | FREE_OBJ_NO_DESTROY_CALLBACK); /* free the inserted object */
                return tmp;
            }
        FOR_INV_FINISH();

        /* the item couldn't merge. */
        object_add_weight(where, op->weight*op->nrof);
    } else
        object_add_weight(where, op->weight+op->carrying);

    op->map = NULL;
    op->env = where;
    op->above = NULL;
    op->below = NULL;
    op->x = 0,
    op->y = 0;
    op->ox = 0,
    op->oy = 0;

    /* Client has no idea of ordering so lets not bother ordering it here.
     * It sure simplifies this function...
     */
    if (where->inv == NULL)
        where->inv = op;
    else {
        op->below = where->inv;
        op->below->above = op;
        where->inv = op;
    }

    /* Update in 2 cases: object goes into player's inventory, or object goes into container the player
     * is looking into. */
    if (where->contr != NULL)
        esrv_send_item(where, op);
    else if (where->type == CONTAINER && QUERY_FLAG(where, FLAG_APPLIED)) {
        object *pl = NULL;

        if (op->env->env && op->env->env->contr)
            /* Container is in player's inventory. */
            pl = op->env->env;
        else if (op->env->map) {
            /* Container on map, look above for player. */
            FOR_ABOVE_PREPARE(op->env, above)
                if (above->contr) {
                    pl = above;
                    break;
                }
            FOR_ABOVE_FINISH();
        }
        if (pl)
            esrv_send_item(pl, op);
    }

    otmp = object_get_player_container(where);
    if (otmp && otmp->contr != NULL) {
        if (!QUERY_FLAG(otmp, FLAG_NO_FIX_PLAYER)
        && (QUERY_FLAG(op, FLAG_APPLIED) || op->type == SKILL || op->glow_radius != 0))
            /* fix_object will only consider applied items, or skills, or items with a glow radius.
               thus no need to call it if our object hasn't that. */
            fix_object(otmp);
    }

    /* reset the light list and los of the players on the map */
    if (op->glow_radius != 0 && where->map) {
#ifdef DEBUG_LIGHTS
        LOG(llevDebug, " object_insert_in_ob(): got %s to insert in map/op\n", op->name);
#endif /* DEBUG_LIGHTS */
        if (MAP_DARKNESS(where->map)) {
            SET_MAP_FLAGS(where->map, where->x, where->y,  P_NEED_UPDATE);
            update_position(where->map, where->x, where->y);
            update_all_los(where->map, where->x, where->y);
        }
    }

    return op;
}

/**
 * Checks if any objects has a move_type that matches objects
 * that effect this object on this space.  Call apply() to process
 * these events.
 *
 * Any speed-modification due to SLOW_MOVE() of other present objects
 * will affect the speed_left of the object.
 * 4-21-95 added code to check if appropriate skill was readied - this will
 * permit faster movement by the player through this terrain. -b.t.
 *
 * MSW 2001-07-08: Check all objects on space, not just those below
 * object being inserted.  object_insert_in_map may not put new objects
 * on top.
 *
 * @param op
 * object that may trigger something.
 * @param originator
 * player, monster or other object that caused 'op' to be inserted
 * into 'map'.  May be NULL.
 * @return
 * 1 if 'op' was destroyed, 0 otherwise.
 */
int object_check_move_on(object *op, object *originator) {
    object *tmp;
    tag_t tag;
    mapstruct *m = op->map;
    int x = op->x, y = op->y;
    MoveType move_on, move_slow, move_block;

    if (QUERY_FLAG(op, FLAG_NO_APPLY))
        return 0;

    tag = op->count;

    move_on = GET_MAP_MOVE_ON(op->map, op->x, op->y);
    move_slow = GET_MAP_MOVE_SLOW(op->map, op->x, op->y);
    move_block = GET_MAP_MOVE_BLOCK(op->map, op->x, op->y);

    /* if nothing on this space will slow op down or be applied,
     * no need to do checking below.    have to make sure move_type
     * is set, as lots of objects don't have it set - we treat that
     * as walking.
     */
    if (op->move_type
    && !(op->move_type&move_on)
    && !(op->move_type&move_slow))
        return 0;

    /* This is basically inverse logic of that below - basically,
     * if the object can avoid the move on or slow move, they do so,
     * but can't do it if the alternate movement they are using is
     * blocked.  Logic on this seems confusing, but does seem correct.
     */
    if ((op->move_type&~move_on&~move_block) != 0
    && (op->move_type&~move_slow&~move_block) != 0)
        return 0;

    /* The objects have to be checked from top to bottom.
     * Hence, we first go to the top:
     */

    tmp = GET_MAP_OB(op->map, op->x, op->y);
    FOR_OB_AND_ABOVE_PREPARE(tmp) {
        if (tmp->above == NULL)
            break;
        /* Trim the search when we find the first other spell effect
         * this helps performance so that if a space has 50 spell objects,
         * we don't need to check all of them.
         */
        if ((tmp->move_type&MOVE_FLY_LOW) && QUERY_FLAG(tmp, FLAG_NO_PICK))
            break;
    } FOR_OB_AND_ABOVE_FINISH();
    FOR_OB_AND_BELOW_PREPARE(tmp) {
        if (tmp == op)
            continue;    /* Can't apply yourself */

        /* Check to see if one of the movement types should be slowed down.
         * Second check makes sure that the movement types not being slowed
         * (~slow_move) is not blocked on this space - just because the
         * space doesn't slow down swimming (for example), if you can't actually
         * swim on that space, can't use it to avoid the penalty.
         */
        if (!QUERY_FLAG(op, FLAG_WIZPASS)) {
            if ((!op->move_type && tmp->move_slow&MOVE_WALK)
            || ((op->move_type&tmp->move_slow) && (op->move_type&~tmp->move_slow&~tmp->move_block) == 0)) {
                float diff;

                diff = tmp->move_slow_penalty*FABS(op->speed);
                if (op->type == PLAYER) {
                    if ((QUERY_FLAG(tmp, FLAG_IS_HILLY) && find_skill_by_number(op, SK_CLIMBING))
                    || (QUERY_FLAG(tmp, FLAG_IS_WOODED) && find_skill_by_number(op, SK_WOODSMAN))) {
                        diff /= 4.0;
                    }
                }
                op->speed_left -= diff;
            }
        }

        /* Basically same logic as above, except now for actual apply. */
        if ((!op->move_type && tmp->move_on&MOVE_WALK)
        || ((op->move_type&tmp->move_on) && (op->move_type&~tmp->move_on&~tmp->move_block) == 0)) {
            ob_move_on(tmp, op, originator);
            if (object_was_destroyed(op, tag))
                return 1;

            /* what the person/creature stepped onto has moved the object
             * someplace new.  Don't process any further - if we did,
             * have a feeling strange problems would result.
             */
            if (op->map != m || op->x != x || op->y != y)
                return 0;
        }
    } FOR_OB_AND_BELOW_FINISH();
    return 0;
}

/**
 * Searches for any objects with a matching archetype at the given map and coordinates.
 *
 * @param m
 * @param x
 * @param y
 * where to search. Must be valid position.
 * @param at
 * archetype to search for.
 * @return
 * first matching object, or NULL if none matches.
 */
object *map_find_by_archetype(mapstruct *m, int x, int y, const archetype *at) {
    if (m == NULL || OUT_OF_REAL_MAP(m, x, y)) {
        LOG(llevError, "Present_arch called outside map.\n");
        return NULL;
    }

    FOR_MAP_PREPARE(m, x, y, tmp)
        if (tmp->arch == at)
            return tmp;
    FOR_MAP_FINISH();

    return NULL;
}

/**
 * Searches for any objects with
 * a matching type variable at the given map and coordinates.
 *
 * @param m
 * @param x
 * @param y
 * where to search. Must be valid position.
 * @param type
 * type to get.
 * @return
 * first matching object, or NULL if none matches.
 */
object *map_find_by_type(mapstruct *m, int x, int y, uint8_t type) {
    if (OUT_OF_REAL_MAP(m, x, y)) {
        return NULL;
    }

    FOR_MAP_PREPARE(m, x, y, tmp)
        if (tmp->type == type)
            return tmp;
    FOR_MAP_FINISH();

    return NULL;
}

/**
 * Searches for any objects with
 * a matching type variable in the inventory of the given object.
 * @param type
 * type to search for.
 * @param op
 * object to search into.
 * @return
 * first matching object, or NULL if none matches.
 */
object *object_present_in_ob(uint8_t type, const object *op) {
    object *tmp;

    for (tmp = op->inv; tmp != NULL; tmp = tmp->below)
        if (tmp->type == type)
            return tmp;

    return NULL;
}

/**
 * Searches for any objects with
 * a matching type & name variable in the inventory of the given object.
 * This is mostly used by spell effect code, so that we only
 * have one spell effect at a time.
 * type can be used to narrow the search - if type is set,
 * the type must also match.  -1 can be passed for the type,
 * in which case the type does not need to pass.
 * str is the string to match against.  Note that we match against
 * the object name, not the archetype name.  this is so that the
 * spell code can use one object type (force), but change it's name
 * to be unique.
 *
 * @param type
 * object type to search for. -1 means to ignore it.
 * @param str
 * object name to search for.
 * @param op
 * where to search.
 * @return
 * first matching object, or NULL if none matches.
 *
 * @todo
 * use add_string() hack to avoid the strcmp?
 */
object *object_present_in_ob_by_name(int type, const char *str, const object *op) {
    object *tmp;

    for (tmp = op->inv; tmp != NULL; tmp = tmp->below) {
        if ((type == -1 || tmp->type == type) && !strcmp(str, tmp->name))
            return tmp;
    }
    return NULL;
}

/**
 * Searches for any objects with a matching archetype in the inventory of the given object.
 *
 * @param at
 * archetype to search for.
 * @param op
 * where to search.
 * @return first matching object, or NULL if none matches.
 */
object *arch_present_in_ob(const archetype *at, const object *op)  {
    object *tmp;

    for (tmp = op->inv; tmp != NULL; tmp = tmp->below)
        if (tmp->arch == at)
            return tmp;
    return NULL;
}

/**
 * Activate recursively a flag on an object's inventory
 *
 * @param op
 * object to recurse. Can have an empty inventory.
 * @param flag
 * flag to set.
 */
void object_set_flag_inv(object*op, int flag) {
    object *tmp;

    for (tmp = op->inv; tmp != NULL; tmp = tmp->below) {
        SET_FLAG(tmp, flag);
        object_set_flag_inv(tmp, flag);
    }
}

/**
 * Desactivate recursively a flag on an object inventory
 *
 * @param op
 * object to recurse. Can have an empty inventory.
 * @param flag
 * flag to unset.
 */
void object_unset_flag_inv(object*op, int flag) {
    object *tmp;

    for (tmp = op->inv; tmp != NULL; tmp = tmp->below) {
        CLEAR_FLAG(tmp, flag);
        object_unset_flag_inv(tmp, flag);
    }
}

/**
 * object_set_cheat(object) sets the cheat flag (WAS_WIZ) in the object and in
 * all it's inventory (recursively).
 * If checksums are used, a player will get object_set_cheat called for
 * him/her-self and all object carried by a call to this function.
 *
 * @param op
 * object for which to set the flag.
 */
void object_set_cheat(object *op) {
    SET_FLAG(op, FLAG_WAS_WIZ);
    object_set_flag_inv(op, FLAG_WAS_WIZ);
}

/**
 * Sets hx and hy to the coords to insert a possibly
 * multi-tile ob at, around gen.
 *
 * @param ob
 * object to insert. Must not be NULL.
 * @param gen
 * where to insert. Must not be NULL.
 * @param[out] hx
 * @param[out] hy
 * coordinates at which insertion is possible.
 * @return
 * 0 for success and -1 for failure.
 *
 * @note
 * This function assumes that multi-tile objects are rectangular.
 */
int object_find_multi_free_spot_around(const object *ob, const object *gen, int16_t *hx, int16_t *hy) {
    int genx, geny, genx2, geny2, sx, sy, sx2, sy2, ix, iy, nx, ny, i, flag;
    int freecount = 0;

    ob = HEAD(ob);

    object_get_multi_size(ob, &sx, &sy, &sx2, &sy2);
    object_get_multi_size(gen, &genx, &geny, &genx2, &geny2);
    /*
     * sx and sy are now the coords of the bottom right corner of ob relative to the head.
     * genx and geny are now the coords of the bottom right corner of gen relative to the head.
     * sx2 and sy2 are now the coords of the head of ob relative to the top left corner.
     * genx2 and geny2 are now the coords of the head of gen relative to the top left corner.
     */

    sx++;
    sy++;
    genx++;
    geny++;
    /*
     * sx, sy, genx, and geny, are now the size of the object, excluding parts left and above
     * the head.
     */

    ix = gen->x-sx-genx2;
    iy = gen->y-sy-geny2;
    sx += genx+sx2;
    sy += geny+sy2;
    /*
     * ix and iy are the map coords of the top left square where the head of ob could possibly
     * be placed. sx and sy are now the size of the square to search for placement of the head
     * relative to ix and iy.
     */

    /*
     * Loop around the square of possible positions for the head of ob object:
     */
    for (i = 0; i < (sx+sx+sy+sy); i++) {
        if (i <= sx) {
            nx = i+ix;
            ny = iy;
        } else if (i <= sx+sy) {
            nx = ix+sx;
            ny = iy+i-sx;
        } else if (i <= sx+sy+sx) {
            nx = ix+sx-(i-(sx+sy));
            ny = iy+sy;
        } else {
            nx = ix;
            ny = iy+sy-(i-(sx+sy+sx));
        }
        /* Check if the spot is free. */
        flag = ob_blocked(ob, gen->map, nx, ny);
        if (!flag) {
            freecount++;
        }
    }
    /* If no free spaces, return. */
    if (!freecount)
        return -1;

    /* Choose a random valid position */
    freecount = RANDOM()%freecount;
    for (i = 0; i < sx+sx+sy+sy; i++) {
        if (i <= sx) {
            nx = i+ix;
            ny = iy;
        } else if (i <= sx+sy) {
            nx = ix+sx;
            ny = iy+i-sx;
        } else if (i <= sx+sy+sx) {
            nx = ix+sx-(i-(sx+sy));
            ny = iy+sy;
        } else {
            nx = ix;
            ny = iy+sy-(i-(sx+sy+sx));
        }

        /* Make sure it's within map. */
        if (nx < 0 || nx >= MAP_WIDTH(gen->map)
        || ny < 0 || ny >= MAP_HEIGHT(gen->map))
            continue;

        /* Check if the spot is free.*/
        flag = ob_blocked(ob, gen->map, nx, ny);
        if (!flag) {
            freecount--;
            if (freecount <= 0) {
                *hx = nx;
                *hy = ny;
                return 0;
            }
        }
    }
    return -1;
}

/**
 * Sets hx and hy to the coords to insert a possibly
 * multi-tile ob at, within radius of generator, which
 * is stored in key_value "generator_radius".  Radius
 * defaults to 1.
 *
 * @param ob
 * object to insert. Must not be NULL.
 * @param gen
 * where to insert. Must not be NULL.
 * @param[out] hx
 * @param[out] hy
 * coordinates at which insertion is possible.
 * @return
 * 0 for success and -1 for failure.
 *
 * @note
 * This function assumes that multi-tile objects are rectangular.
 */
int object_find_multi_free_spot_within_radius(const object *ob, const object *gen, int *hx, int *hy) {
    int genx, geny, genx2, geny2, sx, sy, sx2, sy2, ix, iy, nx, ny, i, flag;
    int8_t x, y, radius;
    int freecount = 0, freecountstop = 0;
    const char *value;
    int8_t *x_array;
    int8_t *y_array;

    /* If radius is not set, default to 1 */
    value = object_get_value(gen, "generator_radius");
    if (value) {
        radius = (int8_t)strtol(value, NULL, 10);
        if (radius < 1) {
            radius = 1;
        }
    } else {
        radius = 1;
    }

    ob = HEAD(ob);

    object_get_multi_size(ob, &sx, &sy, &sx2, &sy2);
    object_get_multi_size(gen, &genx, &geny, &genx2, &geny2);
    /*
     * sx and sy are now the coords of the bottom right corner
     * of ob relative to the head.
     * genx and geny are now the coords of the bottom right corner
     * of gen relative to the head.
     * sx2 and sy2 are now the coords of the head of ob relative
     * to the top left corner.
     * genx2 and geny2 are now the coords of the head of gen relative
     * to the top left corner.
     */

    sx++;
    sy++;
    genx++;
    geny++;
    /*
     * sx, sy, genx, and geny, are now the size of the object,
     * excluding parts left and above the head.
     */

    ix = gen->x-sx-genx2-radius+1;
    iy = gen->y-sy-geny2-radius+1;
    sx += genx+sx2+radius*2-1;
    sy += geny+sy2+radius*2-1;

    /*
     * ix and iy are the map coords of the top left square where
     * the head of ob could possibly be placed. sx and sy are now
     * the size of the square to search for placement of the head
     * relative to ix and iy.
     */

    /* Create arrays large enough to hold free space coordinates */
    x_array = malloc(sx*sy*sizeof(int8_t));
    y_array = malloc(sx*sy*sizeof(int8_t));

    /*
     * Loop through the area of possible positions for the head of ob object:
     */
    for (x = 0; x < sx; x++) {
        for (y = 0; y < sy; y++) {
            nx = ix+x;
            ny = iy+y;


            /* Make sure it's within map. */
            if (get_map_flags(gen->map, NULL, nx, ny, NULL, NULL)&P_OUT_OF_MAP) {
                continue;
            }

            /* Check if the spot is free. */
            flag = ob_blocked(ob, gen->map, nx, ny);
            if (!flag) {
                x_array[freecount] = nx;
                y_array[freecount] = ny;
                freecount++;
            }
        }
    }
    /* If no free spaces, return. */
    if (!freecount) {
        free(x_array);
        free(y_array);
        return -1;
    }

    /* Choose a random valid position */
    freecountstop = RANDOM()%freecount;
    for (i = 0; i < freecount; i++) {
        nx = x_array[i];
        ny = y_array[i];

        /* Check if the spot is free.*/
        flag = ob_blocked(ob, gen->map, nx, ny);
        if (!flag) {
            freecountstop--;
            if (freecountstop <= 0) {
                *hx = nx;
                *hy = ny;
                free(x_array);
                free(y_array);
                return 0;
            }
        }
    }
    free(x_array);
    free(y_array);
    return -1;
}

/**
 * object_find_free_spot(object, map, x, y, start, stop) will search for
 * a spot at the given map and coordinates which will be able to contain
 * the given object.
 *
 * It returns a random choice among the alternatives found.
 *
 * @param ob
 * object to insert.
 * @param m
 * @param x
 * @param y
 * where to insert the object.
 * @param start
 * @param stop
 * first (inclusive) and last (exclusive) positions, in the freearr_ arrays, to search.
 * @return
 * index into ::freearr_x and ::freearr_y, -1 if no spot available (dir 0 = x,y)
 *
 * @note
 * this only checks to see if there is space for the head of the
 * object - if it is a multispace object, this should be called for all
 * pieces.
 * @note
 * This function does correctly handle tiled maps, but does not
 * inform the caller.  However, object_insert_in_map will update as
 * necessary, so the caller shouldn't need to do any special work.
 * @note
 * Updated to take an object instead of archetype - this is necessary
 * because arch_blocked (now ob_blocked) needs to know the movement type
 * to know if the space in question will block the object.  We can't use
 * the archetype because that isn't correct if the monster has been
 * customized, changed states, etc.
 */
int object_find_free_spot(const object *ob, mapstruct *m, int x, int y, int start, int stop) {
    int i, index = 0, flag;
    static int altern[SIZEOFFREE];

    for (i = start; i < stop; i++) {
        flag = ob_blocked(ob, m, x+freearr_x[i], y+freearr_y[i]);
        if (!flag)
            altern[index++] = i;

        /* Basically, if we find a wall on a space, we cut down the search size.
         * In this way, we won't return spaces that are on another side of a wall.
         * This mostly work, but it cuts down the search size in all directions -
         * if the space being examined only has a wall to the north and empty
         * spaces in all the other directions, this will reduce the search space
         * to only the spaces immediately surrounding the target area, and
         * won't look 2 spaces south of the target space.
         */
        else if ((flag&AB_NO_PASS) && maxfree[i] < stop)
            stop = maxfree[i];
    }
    if (!index)
        return -1;
    return altern[RANDOM()%index];
}

/**
 * object_find_first_free_spot(archetype, mapstruct, x, y) works like
 * object_find_free_spot(), but it will search max number of squares.
 * It will return the first available spot, not a random choice.
 * Changed 0.93.2: Have it return -1 if there is no free spot available.
 *
 * @param ob
 * object to insert.
 * @param m
 * @param x
 * @param y
 * where to insert the object.
 * @return
 * index into ::freearr_x and ::freearr_y, -1 if no spot available (dir 0 = x,y)
 */
int object_find_first_free_spot(const object *ob, mapstruct *m, int x, int y) {
    int i;

    for (i = 0; i < SIZEOFFREE; i++) {
        if (!ob_blocked(ob, m, x+freearr_x[i], y+freearr_y[i]))
            return i;
    }
    return -1;
}

/**
 * Randomly permutes an array.
 *
 * @param arr
 * array to permute.
 * @param begin
 * @param end
 * first and last (exclusive) indexes to permute.
 */
static void permute(int *arr, int begin, int end) {
    int i, j, tmp, len;

    len = end-begin;
    for (i = begin; i < end; i++) {
        j = begin+RANDOM()%len;

        tmp = arr[i];
        arr[i] = arr[j];
        arr[j] = tmp;
    }
}

/**
 * New function to make monster searching more efficient, and effective!
 * This basically returns a randomized array (in the passed pointer) of
 * the spaces to find monsters.  In this way, it won't always look for
 * monsters to the north first.  However, the size of the array passed
 * covers all the spaces, so within that size, all the spaces within
 * the 3x3 area will be searched, just not in a predictable order.
 *
 * @param search_arr
 * array that will be initialized. Must contain at least SIZEOFFREE elements.
 */
void get_search_arr(int *search_arr) {
    int i;

    for (i = 0; i < SIZEOFFREE; i++) {
        search_arr[i] = i;
    }

    permute(search_arr, 1, SIZEOFFREE1+1);
    permute(search_arr, SIZEOFFREE1+1, SIZEOFFREE2+1);
    permute(search_arr, SIZEOFFREE2+1, SIZEOFFREE);
}

/**
 * Search some close squares in the given map at the given coordinates for live objects.
 *
 * @param m
 * @param x
 * @param y
 * origin from which to search.
 * @param exclude
 * an object that will be ignored. Can be NULL.
 * @return
 * direction toward the first/closest live object if it finds any, otherwise 0.
 *
 * @note
 * Perhaps incorrectly, but I'm making the assumption that exclude
 * is actually want is going to try and move there.  We need this info
 * because we have to know what movement the thing looking to move
 * there is capable of.
 */
int map_find_dir(mapstruct *m, int x, int y, object *exclude) {
    int i, max = SIZEOFFREE, mflags;
    int16_t nx, ny;
    mapstruct *mp;
    MoveType blocked, move_type;

    if (exclude && exclude->head) {
        exclude = exclude->head;
        move_type = exclude->move_type;
    } else {
        /* If we don't have anything, presume it can use all movement types. */
        move_type = MOVE_ALL;
    }

    for (i = 1; i < max; i++) {
        mp = m;
        nx = x+freearr_x[i];
        ny = y+freearr_y[i];

        mflags = get_map_flags(m, &mp, nx, ny, &nx, &ny);
        if (mflags&P_OUT_OF_MAP) {
            max = maxfree[i];
        } else {
            blocked = GET_MAP_MOVE_BLOCK(mp, nx, ny);

            if ((move_type&blocked) == move_type) {
                max = maxfree[i];
            } else if (mflags&P_IS_ALIVE) {
                FOR_MAP_PREPARE(mp, nx, ny, tmp) {
                    if ((QUERY_FLAG(tmp, FLAG_MONSTER) || tmp->type == PLAYER)
                    && (tmp != exclude || (tmp->head && tmp->head != exclude))) {
                        return freedir[i];
                    }
                } FOR_MAP_FINISH();
            }
        }
    }
    return 0;
}

/**
 * Return the square of the distance between the two given objects.
 *
 * @param ob1
 * @param ob2
 * objects we want to compute the distance of.
 */
int object_distance(const object *ob1, const object *ob2) {
    int i;

    i = (ob1->x-ob2->x)*(ob1->x-ob2->x)+
        (ob1->y-ob2->y)*(ob1->y-ob2->y);
    return i;
}

/**
 * Computes a direction which you should travel to move of x and y.
 * @param x
 * @param y
 * delta.
 * @return
 * direction
 */
int find_dir_2(int x, int y) {
    int q;

    if (!y)
        q = -300*x;
    else
        q = x*100/y;
    if (y > 0) {
        if (q < -242)
            return 3;
        if (q < -41)
            return 2;
        if (q < 41)
            return 1;
        if (q < 242)
            return 8;
        return 7;
    }
    if (q < -242)
        return 7;
    if (q < -41)
        return 6;
    if (q < 41)
        return 5;
    if (q < 242)
        return 4;
    return 3;
}

/**
 * Computes an absolute direction.
 * @param d
 * direction to convert.
 * @return
 * number between 1 and 8, which represent the "absolute" direction of a number (it actually
 * takes care of "overflow" in previous calculations of a direction).
 */
int absdir(int d) {
    // Shortcut for modulus that work becuase we have a power of 2
    d &= 7;
    // 0 needs to be 8
    if (!d)
	d = 8;
    return d;
}

/**
 * Computes a direction difference.
 * @param dir1
 * @param dir2
 * directions to compare.
 * @return
 * how many 45-degrees differences there is between two directions
 * (which are expected to be absolute (see absdir())
 */
int dirdiff(int dir1, int dir2) {
    int d;

    d = abs(dir1-dir2);
    if (d > 4)
        d = 8-d;
    return d;
}

/**
 * Basically, this is a table of directions, and what directions
 * one could go to go back to us.  Eg, entry 15 below is 4, 14, 16.
 * This basically means that if direction is 15, then it could either go
 * direction 4, 14, or 16 to get back to where we are.
 * Moved from spell_util.c to object.c with the other related direction
 * functions.
 *
 * peterm:
 * do LOS stuff for ball lightning.  Go after the closest VISIBLE monster.
 */
static const int reduction_dir[SIZEOFFREE][3] = {
    {  0,  0,  0 }, /* 0 */
    {  0,  0,  0 }, /* 1 */
    {  0,  0,  0 }, /* 2 */
    {  0,  0,  0 }, /* 3 */
    {  0,  0,  0 }, /* 4 */
    {  0,  0,  0 }, /* 5 */
    {  0,  0,  0 }, /* 6 */
    {  0,  0,  0 }, /* 7 */
    {  0,  0,  0 }, /* 8 */
    {  8,  1,  2 }, /* 9 */
    {  1,  2, -1 }, /* 10 */
    {  2, 10, 12 }, /* 11 */
    {  2,  3, -1 }, /* 12 */
    {  2,  3,  4 }, /* 13 */
    {  3,  4, -1 }, /* 14 */
    {  4, 14, 16 }, /* 15 */
    {  5,  4, -1 }, /* 16 */
    {  4,  5,  6 }, /* 17 */
    {  6,  5, -1 }, /* 18 */
    {  6, 20, 18 }, /* 19 */
    {  7,  6, -1 }, /* 20 */
    {  6,  7,  8 }, /* 21 */
    {  7,  8, -1 }, /* 22 */
    {  8, 22, 24 }, /* 23 */
    {  8,  1, -1 }, /* 24 */
    { 24,  9, 10 }, /* 25 */
    {  9, 10, -1 }, /* 26 */
    { 10, 11, -1 }, /* 27 */
    { 27, 11, 29 }, /* 28 */
    { 11, 12, -1 }, /* 29 */
    { 12, 13, -1 }, /* 30 */
    { 12, 13, 14 }, /* 31 */
    { 13, 14, -1 }, /* 32 */
    { 14, 15, -1 }, /* 33 */
    { 33, 15, 35 }, /* 34 */
    { 16, 15, -1 }, /* 35 */
    { 17, 16, -1 }, /* 36 */
    { 18, 17, 16 }, /* 37 */
    { 18, 17, -1 }, /* 38 */
    { 18, 19, -1 }, /* 39 */
    { 41, 19, 39 }, /* 40 */
    { 19, 20, -1 }, /* 41 */
    { 20, 21, -1 }, /* 42 */
    { 20, 21, 22 }, /* 43 */
    { 21, 22, -1 }, /* 44 */
    { 23, 22, -1 }, /* 45 */
    { 45, 47, 23 }, /* 46 */
    { 23, 24, -1 }, /* 47 */
    { 24,  9, -1 }  /* 48 */
};

/**
 * Recursive routine to see if we can find a path to a certain point.
 *
 * Modified to be map tile aware -.MSW
 *
 * @param m
 * map we're on
 * @param x
 * @param y
 * origin coordinates
 * @param dir
 * direction we're going to. Must be less than SIZEOFFREE.
 * @return
 * 1 if we can see a direct way to get it
 *
 * @todo
 * better document, can't figure what it does :)
 */
int can_see_monsterP(mapstruct *m, int x, int y, int dir) {
    int16_t dx, dy;
    int mflags;

    if (dir < 0)
        return 0; /* exit condition:  invalid direction */

    dx = x+freearr_x[dir];
    dy = y+freearr_y[dir];

    mflags = get_map_flags(m, &m, dx, dy, &dx, &dy);

    /* This functional arguably was incorrect before - it was
     * checking for P_WALL - that was basically seeing if
     * we could move to the monster - this is being more
     * literal on if we can see it.  To know if we can actually
     * move to the monster, we'd need the monster passed in or
     * at least its move type.
     */
    if (mflags&(P_OUT_OF_MAP|P_BLOCKSVIEW))
        return 0;

    /* yes, can see. */
    if (dir < 9)
        return 1;
    return can_see_monsterP(m, x, y, reduction_dir[dir][0])|
           can_see_monsterP(m, x, y, reduction_dir[dir][1])|
           can_see_monsterP(m, x, y, reduction_dir[dir][2]);
}

/**
 * Finds out if an object can be picked up.
 *
 * Add a check so we can't pick up invisible objects (0.93.8)
 *
 * @param who
 * who is trying to pick up. Can be a monster or a player.
 * @param item
 * item we're trying to pick up.
 * @return
 * 1 if it can be picked up, otherwise 0.
 *
 * @note
 * this introduces a weight limitation for monsters.
 */
int object_can_pick(const object *who, const object *item) {
    /* I re-wrote this as a series of if statements
     * instead of a nested return (foo & bar && yaz)
     * - I think this is much more readable,
     * and likely compiler effectively optimizes it the
     * same.
     */
    if (item->weight <= 0)
        return 0;
    if (QUERY_FLAG(item, FLAG_NO_PICK))
        return 0;
    if (QUERY_FLAG(item, FLAG_ALIVE))
        return 0;
    if (item->invisible)
        return 0;
    if (item->type == TRANSPORT && item->contr != NULL) {
        return 0;
    }

    /* Weight limit for monsters */
    if (who->type != PLAYER && ((uint32_t)(who->weight+who->carrying+item->weight)) > get_weight_limit(who->stats.Str))
        return 0;

    /* Can not pick up multipart objects */
    if (item->head || item->more)
        return 0;

    /* Everything passes, so OK to pick up */
    return 1;
}

/**
 * Create clone from object to another.
 *
 * @param asrc
 * object to clone.
 * @return
 * clone of asrc, including inventory and 'more' body parts.
 *
 * @note
 * this function will return NULL only if asrc is NULL. If there is a memory allocation error, object_new() calls fatal().
 */
object *object_create_clone(object *asrc) {
    object *dst = NULL, *tmp, *src, *part, *prev;

    if (!asrc)
        return NULL;
    src = HEAD(asrc);

    prev = NULL;
    for (part = src; part; part = part->more) {
        tmp = object_new();
        object_copy(part, tmp);
        /*
         * Need to reset the weight, since object_insert_in_ob() later will
         * recompute this field.
         */
        tmp->carrying = tmp->arch->clone.carrying;
        tmp->x -= src->x;
        tmp->y -= src->y;
        if (!part->head) {
            dst = tmp;
            tmp->head = NULL;
        } else {
            tmp->head = dst;
        }
        tmp->more = NULL;
        if (prev)
            prev->more = tmp;
        prev = tmp;
    }
    /*** copy inventory ***/
    FOR_INV_PREPARE(src, item)
        (void)object_insert_in_ob(object_create_clone(item), dst);
    FOR_INV_FINISH();

    return dst;
}

/**
 * Finds an object in inventory name.
 *
 * @param who
 * the object to search
 * @param name
 * name to search for
 * @return
 * the first object which has a name equal to the argument, NULL if none found.
 */
object *object_find_by_name(const object *who, const char *name) {
    const char *name_shared = add_string(name);
    object *tmp;

    for (tmp = who->inv; tmp; tmp = tmp->below)
        if (tmp->name == name_shared)
            break;
    free_string(name_shared);
    return tmp;
}

/**
 * Find object in inventory.
 *
 * @param who
 * where to search.
 * @param type
 * what to search.
 * @return
 * first object in who's inventory that has the same type match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_type(const object *who, int type) {
    object *tmp;

    for (tmp = who->inv; tmp; tmp = tmp->below)
        if (tmp->type == type)
            return tmp;

    return NULL;
}

/**
 * Find an object in inventory that does not have any of the provided flags set.
 *
 * @param who
 * where to search.
 * @param type
 * what to search.
 * @param flags
 * Array of integers corresponding to the set of flags that cannot have any set on the found item.
 * @param num_flags
 * The size of the array flags above
 * @return
 * first object in inventory that matches type and lacks any of the specified flags
 */
object *object_find_by_type_without_flags(const object *who, int type, int *flags, int num_flags) {
    int flag_okay;
    for (object *tmp = who->inv; tmp; tmp = tmp->below)
        if (tmp->type == type) {
            flag_okay = 1;
            for (int i = 0; i < num_flags; ++i) {
                if (QUERY_FLAG(tmp, flags[i])) {
                    flag_okay = 0; // A flag we didn't want set was set. Skip this item.
                    break;
                }
            }
            if (flag_okay) // If flag_okay == 1, then the flags specified were not set
                return tmp; // If we reach here, none of the flags specified were set. Just like we wanted.
        }

    return NULL;
}

/**
 * Find object in inventory.
 *
 * @param who
 * where to search.
 * @param type1
 * what to search.
 * @param type2
 * what to search.
 * @return
 * first object in who's inventory that has either type match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_type2(const object *who, int type1, int type2) {
    object *tmp;

    for (tmp = who->inv; tmp; tmp = tmp->below)
        if (tmp->type == type1 || tmp->type == type2)
            return tmp;

    return NULL;
}

/**
 * Find object in inventory.
 *
 * @param who
 * where to search.
 * @param tag
 * what to search.
 * @return
 * first object in who's inventory that has the given tag. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_tag(const object *who, tag_t tag) {
    object *tmp;

    for (tmp = who->inv; tmp; tmp = tmp->below)
        if (tmp->count == tag)
            return tmp;

    return NULL;
}

/**
 * Find applied object in inventory.
 *
 * @param who
 * where to search.
 * @param type
 * what to search.
 * @return
 * first object in who's inventory that has the same type match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_type_applied(const object *who, int type) {
    object *tmp;

    for (tmp = who->inv; tmp != NULL; tmp = tmp->below)
        if (tmp->type == type && QUERY_FLAG(tmp, FLAG_APPLIED))
            return tmp;

    return NULL;
}

/**
 * Find object in inventory by type and name.
 *
 * @param who
 * where to search.
 * @param type
 * what to search.
 * @param name
 * what to search
 * @return
 * first object in who's inventory that has the same type and name match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_type_and_name(const object *who, int type, const char *name) {
    object *tmp;

    for (tmp = who->inv; tmp != NULL; tmp = tmp->below)
        if (tmp->type == type && strcmp(tmp->name, name) == 0)
            return tmp;

    return NULL;
}

/**
 * Find object in inventory by type and race.
 *
 * @param who
 * where to search.
 * @param type
 * what to search.
 * @param race
 * what to search
 * @return
 * first object in who's inventory that has the same type and race match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_type_and_race(const object *who, int type, const char *race) {
    object *tmp;

    for (tmp = who->inv; tmp != NULL; tmp = tmp->below)
        if (tmp->type == type && strcmp(tmp->race, race) == 0)
            return tmp;

    return NULL;
}

/**
 * Find object in inventory by type and slaying.
 *
 * @param who
 * where to search.
 * @param type
 * what to search.
 * @param slaying
 * what to search
 * @return
 * first object in who's inventory that has the same type and slaying match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_type_and_slaying(const object *who, int type, const char *slaying) {
    object *tmp;

    for (tmp = who->inv; tmp != NULL; tmp = tmp->below)
        if (tmp->type == type && tmp->slaying != NULL && strcmp(tmp->slaying, slaying) == 0)
            return tmp;

    return NULL;
}

/**
 * Find object in inventory by type and skill.
 *
 * @param who
 * where to search.
 * @param type
 * what to search.
 * @param skill
 * what to search
 * @return
 * first object in who's inventory that has the same type and skill match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_type_and_skill(const object *who, int type, const char *skill) {
    object *tmp;

    for (tmp = who->inv; tmp != NULL; tmp = tmp->below)
        if (tmp->type == type && tmp->skill != NULL && strcmp(tmp->skill, skill) == 0)
            return tmp;

    return NULL;
}

/**
 * Find object in inventory by flag.
 *
 * @param who
 * where to search.
 * @param flag
 * what to search.
 * @return
 * first object in who's inventory that has the flag set. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_flag(const object *who, int flag) {
    object *tmp;

    for (tmp = who->inv; tmp != NULL; tmp = tmp->below)
        if (QUERY_FLAG(tmp, flag))
            return tmp;

    return NULL;
}

/**
 * Find applied object in inventory by flag.
 *
 * @param who
 * where to search.
 * @param flag
 * what to search.
 * @return
 * first object in who's inventory that has the flag set and is applied. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_flag_applied(const object *who, int flag) {
    object *tmp;

    for (tmp = who->inv; tmp != NULL; tmp = tmp->below)
        if (QUERY_FLAG(tmp, FLAG_APPLIED) && QUERY_FLAG(tmp, flag))
            return tmp;

    return NULL;
}

/**
 * Find object in inventory by archetype name.
 *
 * @param who
 * where to search.
 * @param name
 * what to search.
 * @return
 * first object in who's inventory that has the archetype name match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_arch_name(const object *who, const char *name) {
    object *tmp;

    for (tmp = who->inv; tmp != NULL; tmp = tmp->below)
        if (strcmp(tmp->arch->name, name) == 0)
            return tmp;

    return NULL;
}

/**
 * Find object in inventory by type and archetype name.
 *
 * @param who
 * where to search.
 * @param type
 * what to search.
 * @param name
 * what to search.
 * @return
 * first object in who's inventory that has the type and archetype name match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_type_and_arch_name(const object *who, int type, const char *name) {
    object *tmp;

    for (tmp = who->inv; tmp != NULL; tmp = tmp->below)
        if (tmp->type == type && strcmp(tmp->arch->name, name) == 0)
            return tmp;

    return NULL;
}

/**
 * Find object in inventory.
 *
 * @param who
 * where to search.
 * @param type
 * @param subtype
 * what to search.
 * @return
 * first object in who's inventory that has the same type and subtype match. NULL if no match.
 *
 * @note
 * will not search in inventory of items in inventory.
 */
object *object_find_by_type_subtype(const object *who, int type, int subtype) {
    object *tmp;

    for (tmp = who->inv; tmp; tmp = tmp->below)
        if (tmp->type == type && tmp->subtype == subtype)
            return tmp;

    return NULL;
}

/**
 * Search for a field by key.
 *
 * @param ob
 * object where search
 * @param key
 * key to search. Must be a passed in shared string - otherwise, this won't do the desired thing.
 * @return
 * the link from the list if ob has a field named key, otherwise NULL.
 */
key_value *object_get_key_value(const object *ob, const char *key) {
    key_value *link;

    for (link = ob->key_values; link != NULL; link = link->next) {
        if (link->key == key) {
            return link;
        }
    }

    return NULL;
}

/**
 * Get an extra value by key.
 *
 * @param op
 * object we're considering
 * @param key
 * key of which to retrieve the value. Doesn't need to be a shared string.
 * @return
 * the value of op has in an extra_field for key, or NULL if it doesn't have the key.
 *
 * @note
 * The returned string is shared.
 */
const char *object_get_value(const object *op, const char *const key) {
    key_value *link;
    const char *canonical_key;

    canonical_key = find_string(key);

    if (canonical_key == NULL) {
        /* 1. There being a field named key on any object
         *    implies there'd be a shared string to find.
         * 2. Since there isn't, no object has this field.
         * 3. Therefore, *this *object doesn't have this field.
         */
        return NULL;
    }

    /* This is copied from object_get_key_value() above -
     * only 4 lines, and saves the function call overhead.
     */
    for (link = op->key_values; link != NULL; link = link->next) {
        if (link->key == canonical_key) {
            return link->value;
        }
    }
    return NULL;
}

/**
 * Updates or sets a key value.
 *
 * @param op
 * object we're considering.
 * @param canonical_key
 * key to set or update. Must be a shared string.
 * @param value
 * value to set. Doesn't need to be a shared string.
 * @param add_key
 * if 0, will not add the key if it doesn't exist in op.
 * @return
 * TRUE if key was updated or added, FALSE else.
 */
static int object_set_value_s(object *op, const char *canonical_key, const char *value, int add_key) {
    key_value *field = NULL, *last = NULL;

    for (field = op->key_values; field != NULL; field = field->next) {
        if (field->key != canonical_key) {
            last = field;
            continue;
        }

        if (field->value)
            FREE_AND_CLEAR_STR(field->value);
        if (value)
            field->value = add_string(value);
        else {
            /* Basically, if the archetype has this key set,
             * we need to store the null value so when we save
             * it, we save the empty value so that when we load,
             * we get this value back again.
             */
            if (object_get_key_value(&op->arch->clone, canonical_key))
                field->value = NULL;
            else {
                /* Delete this link */
                if (field->key)
                    FREE_AND_CLEAR_STR(field->key);
                if (field->value)
                    FREE_AND_CLEAR_STR(field->value);
                if (last)
                    last->next = field->next;
                else
                    op->key_values = field->next;
                free(field);
            }
        }
        return TRUE;
    }
    /* IF we get here, key doesn't exist */

    /* No field, we'll have to add it. */

    if (!add_key) {
        return FALSE;
    }
    /* There isn't any good reason to store a null
     * value in the key/value list.  If the archetype has
     * this key, then we should also have it, so shouldn't
     * be here.  If user wants to store empty strings,
     * should pass in ""
     */
    if (value == NULL)
        return TRUE;

    field = malloc(sizeof(key_value));

    field->key = add_refcount(canonical_key);
    field->value = add_string(value);
    /* Usual prepend-addition. */
    field->next = op->key_values;
    op->key_values = field;

    return TRUE;
}

/**
 * Updates the key in op to value.
 *
 * @param op
 * object we're considering.
 * @param key
 * key to set or update. Doesn't need to be a shared string.
 * @param value
 * value to set. Doesn't need to be a shared string.
 * @param add_key
 * if 0, will not add the key if it doesn't exist in op.
 * @return
 * TRUE if key was updated or added, FALSE else.
 *
 * @note
 * This function is merely a wrapper to object_set_value_s() to ensure the key is a shared string.
 *
 * @note
 * In general, should be little reason FALSE is ever passed in for add_key
*/
int object_set_value(object *op, const char *key, const char *value, int add_key) {
    const char *canonical_key = NULL;
    int floating_ref = FALSE;
    int ret;

    /* HACK This mess is to make sure set_ob_value() passes a shared string
     * to object_get_key_value(), without leaving a leaked refcount.
     */

    canonical_key = find_string(key);
    if (canonical_key == NULL) {
        canonical_key = add_string(key);
        floating_ref = TRUE;
    }

    ret = object_set_value_s(op, canonical_key, value, add_key);

    if (floating_ref) {
        free_string(canonical_key);
    }

    return ret;
}

/** This is a subset of the parse_id command.  Basically, name can be
 * a string seperated lists of things to match, with certain keywords.
 * pl is the player (only needed to set count properly)
 * op is the item we are trying to match.  Calling function takes care
 * of what action might need to be done and if it is valid
 * (pickup, drop, etc.)  Return NONZERO if we have a match.  A higher
 * value means a better match.  0 means no match.
 *
 * Brief outline of the procedure:
 * We take apart the name variable into the individual components.
 * cases for 'all' and unpaid are pretty obvious.
 * Next, we check for a count (either specified in name, or in the
 * player object.)
 * If count is 1, make a quick check on the name.
 * IF count is >1, we need to make plural name.  Return if match.
 * Last, make a check on the full name.
 *
 * Details on values output (highest is output):
 * match type                 return value
 * ---------------------------------------
 * nothing                    0
 * 'all'                      1
 * 'unpaid'                   2
 * 'cursed'                   2
 * 'unlocked'                 2
 * partial custom name        3
 * op->name with count >1     4
 * op->name with count <2     6
 * op->name_pl with count >1  6
 * inside base name           12
 * inside short name          12
 * begin of base name         14
 * custom name                15
 * base name                  16
 * short name                 18
 * full name                  20
 * (note, count is extracted from begin of name parameter or
 *  from pl->contr->count, name has priority)
 *
 * @param pl
 * object we're searching an item for. Must not be NULL.
 * @param op
 * object we're considering. Must not be NULL.
 * @param name
 * string we're searching.
 * @return
 * matching weight. The higher, the more the object matches.
 *
 * @todo
 * is the player->contr->count hack used?? Try to reduce buffers/calls to query_ functions.
 */
int object_matches_string(object *pl, object *op, const char *name) {
    char *cp, local_name[MAX_BUF], name_op[MAX_BUF], name_short[HUGE_BUF], bname_s[MAX_BUF], bname_p[MAX_BUF];
    int count, retval = 0;
    /* strtok is destructive to name */
    safe_strncpy(local_name, name, sizeof(local_name));

    for (cp = strtok(local_name, ","); cp; cp = strtok(NULL, ",")) {
        while (cp[0] == ' ')
            ++cp;    /* get rid of spaces */

        /*  LOG(llevDebug, "Trying to match %s\n", cp);*/
        /* All is a very generic match - low match value */
        if (!strcmp(cp, "all"))
            return 1;

        /* unpaid is a little more specific */
        if (!strcmp(cp, "unpaid") && QUERY_FLAG(op, FLAG_UNPAID))
            return 2;
        if (!strcmp(cp, "cursed")
        && QUERY_FLAG(op, FLAG_KNOWN_CURSED)
        && (QUERY_FLAG(op, FLAG_CURSED) || QUERY_FLAG(op, FLAG_DAMNED)))
            return 2;

        if (!strcmp(cp, "unlocked") && !QUERY_FLAG(op, FLAG_INV_LOCKED))
            return 2;

        /* Allow for things like '100 arrows' */
        count = atoi(cp);
        if (count != 0) {
            cp = strchr(cp, ' ');
            while (cp && cp[0] == ' ')
                ++cp;  /* get rid of spaces */
        } else {
            if (pl->type == PLAYER)
                count = pl->contr->count;
            else
                count = 0;
        }

        if (!cp || cp[0] == '\0' || count < 0)
            return 0;

        /* The code here should go from highest retval to lowest.  That
         * is because of the 'else' handling - we don't want to match on
         * something and set a low retval, even though it may match a higher retcal
         * later.  So keep it in descending order here, so we try for the best
         * match first, and work downward.
         */
        query_name(op, name_op, MAX_BUF);
        query_short_name(op, name_short, HUGE_BUF);
        query_base_name(op, 0, bname_s, MAX_BUF);
        query_base_name(op, 1, bname_p, MAX_BUF);

        if (!strcasecmp(cp, name_op))
            retval = 20;
        else if (!strcasecmp(cp, name_short))
            retval = 18;
        else if (!strcasecmp(cp, bname_s))
            retval = 16;
        else if (!strcasecmp(cp, bname_p))
            retval = 16;
        else if (op->custom_name && !strcasecmp(cp, op->custom_name))
            retval = 15;
        else if (!strncasecmp(cp, bname_s, strlen(cp)))
            retval = 14;
        else if (!strncasecmp(cp, bname_p, strlen(cp)))
            retval = 14;
        /* Do substring checks, so things like 'Str+1' will match.
         * retval of these should perhaps be lower - they are lower
         * then the specific strcasecmp aboves, but still higher than
         * some other match criteria.
         */
        else if (strstr(bname_p, cp))
            retval = 12;
        else if (strstr(bname_s, cp))
            retval = 12;
        else if (strstr(name_short, cp))
            retval = 12;
        /* Check against plural/non plural based on count. */
        else if (count > 1 && !strcasecmp(cp, op->name_pl)) {
            retval = 6;
        } else if (count == 1 && !strcasecmp(op->name, cp)) {
            retval = 6;
        }
        /* base name matched - not bad */
        else if (strcasecmp(cp, op->name) == 0 && !count)
            retval = 4;
        /* Check for partial custom name, but give a real low priority */
        else if (op->custom_name && strstr(op->custom_name, cp))
            retval = 3;

        if (retval) {
            if (pl->type == PLAYER)
                pl->contr->count = count;
            return retval;
        }
    }
    return 0;
}

/**
 * Ensures specified object has its more parts correctly inserted in map.
 *
 * Extracted from common/map.c:link_multipart_objects
 *
 * @param tmp
 * object we want to fix. Must be on a map.
 */
void object_fix_multipart(object *tmp) {
    archetype *at;
    object *op, *last;

    if (!tmp->map) {
        LOG(llevError, "object_fix_multipart: not on a map!\n");
        return;
    }

    /* already multipart - don't do anything more */
    if (tmp->head || tmp->more)
        return;

    /* If there is nothing more to this object, this for loop
     * won't do anything.
     */
    for (at = tmp->arch->more, last = tmp; at != NULL; at = at->more, last = op) {
        op = arch_to_object(at);

        /* update x,y coordinates */
        op->x += tmp->x;
        op->y += tmp->y;
        op->head = tmp;
        op->map = tmp->map;
        last->more = op;
        if (tmp->name != op->name) {
            if (op->name)
                free_string(op->name);
            op->name = add_string(tmp->name);
        }
        if (tmp->title != op->title) {
            if (op->title)
                free_string(op->title);
            op->title = add_string(tmp->title);
        }
        /* we could link all the parts onto tmp, and then just
         * call object_insert_in_map once, but the effect is the same,
         * as object_insert_in_map will call itself with each part, and
         * the coding is simpler to just to it here with each part.
         */
        object_insert_in_map(op, op->map, tmp, INS_NO_MERGE|INS_ABOVE_FLOOR_ONLY|INS_NO_WALK_ON);
    } /* for at = tmp->arch->more */
}

/**
 * Computes the size of a multitile object.
 *
 * @param ob
 * object we compute the size of.
 * @param[out] sx
 * @param[out] sy
 * will contain the coords of the bottom right tail relative to the head. Must not be NULL.
 * @param[out] hx
 * @param[out] hy
 * will contain the coords of the head tile relative to the top left tile. Can be NULL.
 *
 * @todo
 * either check for sx/sy everywhere or remove the check :)
 */
void object_get_multi_size(const object *ob, int *sx, int *sy, int *hx, int *hy) {
    archetype *part;
    int maxx = 0, maxy = 0, minx = 0, miny = 0;

    ob = HEAD(ob);
    *sx = 1;
    *sy = 1;
    if (ob->arch->more) {
        for (part = ob->arch; part; part = part->more) {
            if (part->clone.x > maxx)
                maxx = part->clone.x;
            if (part->clone.y > maxy)
                maxy = part->clone.y;
            if (part->clone.x < minx)
                minx = part->clone.x;
            if (part->clone.y < miny)
                miny = part->clone.y;
        }
    }
    if (sx)
        *sx = maxx;
    if (sy)
        *sy = maxy;
    if (hx)
        *hx = -minx;
    if (hy)
        *hy = -miny;
}

/**
 * Inserts an object into its map. The object is inserted into a free spot (as
 * returned by #object_find_free_spot()). If no free spot can be found, the
 * object is freed.
 *
 * @param op
 * the object to insert or free
 * @param map
 * the map to insert into
 * @param x
 * the x-coordinate to insert into
 * @param y
 * the y-coordinate to insert into
 * @param start
 * first (inclusive) position in the freearr_ arrays to search
 * @param stop
 * last (exclusive) position in the freearr_ arrays to search
 * @param originator
 * what caused op to be inserted.
 */
void object_insert_to_free_spot_or_free(object *op, mapstruct *map, int x, int y, int start, int stop, object *originator) {
    int pos;

    pos = object_find_free_spot(op, map, x, y, start, stop);
    if (pos == -1) {
        object_free_drop_inventory(op);
        return;
    }

    object_insert_in_map_at(op, map, originator, 0, x+freearr_x[pos], y+freearr_y[pos]);
}

/**
 * Set the message field of an object.
 *
 * @param op
 * the object to modify
 * @param msg
 * the new message to set or NULL to clear
 */
void object_set_msg(object *op, const char *msg) {
    if (op->msg != NULL) {
        free_string(op->msg);
    }

    if (msg != NULL) {
        // If the message does not have a trailing newline, add one.
        if (*msg != '\0' && strchr(msg, '\0')[-1] != '\n') {
            StringBuffer *sb = stringbuffer_new();
            stringbuffer_append_string(sb, msg);
            stringbuffer_append_string(sb, "\n");
            op->msg = stringbuffer_finish_shared(sb);
        } else {
            op->msg = add_string(msg);
        }
    } else {
        op->msg = NULL;
    }
}

/** Maps the MOVE_* values to names */
const char *const move_name[] = {
    "walk",
    "fly_low",
    "fly_high",
    "swim",
    "boat",
    NULL
};

/* This array equates the FLAG_ values with the V_ values.  Use -1 to
 * put gaps in the array that should not be processed.
 * The order matches the order of the define values in 'define.h'.
 */
/**
 * This is a list of pointers that correspond to the FLAG_.. values.
 * This is a simple 1:1 mapping - if FLAG_FRIENDLY is 15, then
 * the 15'th element of this array should match that name.
 * If an entry is NULL, that is a flag not to loaded/saved.
 */
static const char *const flag_names[NUM_FLAGS+1] = {
    "alive", "wiz", NULL, NULL, "was_wiz", "applied", "unpaid",
    "can_use_shield", "no_pick", "client_anim_sync", "client_anim_random", /* 10 */
    "is_animated", NULL /* FLAG_DIALOG_PARSED, not saved */,
    NULL /* flying */, "monster", "friendly", "generator",
    "is_thrown", "auto_apply", "treasure", "player sold",           /* 20 */
    "see_invisible", "can_roll", "overlay_floor",
    "is_turnable", NULL /* walk_off */, NULL /* fly_on */,
    NULL /*fly_off*/, "is_used_up", "identified", "reflecting",     /* 30 */
    "changing", "splitting", "hitback", "startequip",
    "blocksview", "undead", "scared", "unaggressive",
    "reflect_missile", "reflect_spell",                             /* 40 */
    "no_magic", "no_fix_player", "is_lightable", "tear_down",
    "run_away", NULL /*pass_thru */, NULL /*can_pass_thru*/,
    NULL /*"pick_up"*/, "unique", "no_drop",                        /* 50 */
    NULL /* wizcast*/, "can_cast_spell", "can_use_scroll", "can_use_range",
    "can_use_bow",  "can_use_armour", "can_use_weapon",
    "can_use_ring", "has_ready_range", "has_ready_bow",             /* 60 */
    "xrays", NULL, "is_floor", "lifesave", "no_strength", "sleep",
    "stand_still", "random_movement", "only_attack", "confused",    /* 70 */
    "stealth", NULL, NULL, "cursed", "damned",
    "see_anywhere", "known_magical", "known_cursed",
    "can_use_skill", "been_applied",                                /* 80 */
    "has_ready_scroll", NULL, NULL,
    NULL, "make_invisible",  "inv_locked", "is_wooded",
    "is_hilly", "has_ready_skill", "has_ready_weapon",              /* 90 */
    "no_skill_ident", "is_blind", "can_see_in_dark", "is_cauldron",
    NULL, "no_steal", "one_hit", NULL, "berserk", "neutral",   /* 100 */
    "no_attack", "no_damage", NULL, NULL, "activate_on_push",
    "activate_on_release", "is_water", "use_content_on_gen", NULL, "is_buildable",   /* 110 */
    NULL, "blessed", "known_blessed"
};

/**
 * This returns a string of the integer movement type
 *
 * @param sb
 * buffer that will contain the description. Must not be NULL.
 * @param mt
 * move to describe.
 */
static void get_string_move_type(StringBuffer *sb, MoveType mt)
{
    static char retbuf[MAX_BUF], retbuf_all[MAX_BUF];
    int i, all_count = 0, count;

    strcpy(retbuf, "");
    strcpy(retbuf_all, " all");

    /* Quick check, and probably fairly common */
    if (mt == MOVE_ALL) {
        stringbuffer_append_string(sb, "all");
        return;
    }
    if (mt == 0) {
        stringbuffer_append_string(sb, "0");
        return;
    }

    /* We basically slide the bits down.  Why look at MOVE_ALL?
     * because we may want to return a string like 'all -swim',
     * and if we just looked at mt, we couldn't get that.
     */
    for (i = MOVE_ALL, count = 0; i != 0; i >>= 1, count++) {
        if (mt&(1<<count)) {
            strcat(retbuf, " ");
            strcat(retbuf, move_name[count]);
        } else {
            strcat(retbuf_all, " -");
            strcat(retbuf_all, move_name[count]);
            all_count++;
        }
    }
    /* Basically, if there is a single negation, return it, eg
     * 'all -swim'.  But more than that, just return the
     * enumerated values.  It doesn't make sense to return
     * 'all -walk -fly_low' - it is shorter to return 'fly_high swim'
     */
    if (all_count <= 1)
        stringbuffer_append_string(sb, retbuf_all+1);
    else
        stringbuffer_append_string(sb, retbuf+1);
}

/** Adds a line to the buffer. */
static inline void ADD_STRINGLINE_ENTRY(StringBuffer *sb, const char *name, const char *value) {
    stringbuffer_append_string(sb, name);
    stringbuffer_append_string(sb, value);
    stringbuffer_append_string(sb, "\n");
}

/** Adds a long to the buffer.  name must have a space at the end. */
static inline void FAST_SAVE_LONG(StringBuffer *sb, const char *name, const long value) {
    stringbuffer_append_printf(sb, "%s%ld\n", name, (long int)value);
}

/** Adds a double to the buffer. name must have a space at the end. */
static inline void FAST_SAVE_DOUBLE(StringBuffer *sb, const char *name, const double value) {
    stringbuffer_append_printf(sb, "%s%f\n", name, value);
}

/**
 * Returns a pointer to a static string which contains all variables
 * which are different in the two given objects.
 *
 * This function is typically used to dump objects (op2=empty object), or to save objects
 *
 * @param sb
 * buffer that will contain the difference.
 * @param op
 * what object the different values will be taken from.
 * @param op2
 * object's original archetype.
 */
void get_ob_diff(StringBuffer *sb, const object *op, const object *op2) {
    static char buf2[64];
    int tmp;
    int i;
    key_value *my_field;
    key_value *arch_field;

    /* This saves the key/value lists.  We do it first so that any
    * keys that match field names will be overwritten by the loader.
    */
    for (my_field = op->key_values; my_field != NULL; my_field = my_field->next) {
        /* Find the field in the opposing member. */
        arch_field = object_get_key_value(op2, my_field->key);

        /* If there's no partnering field, or it's got a different value, save our field. */
        if (arch_field == NULL || my_field->value != arch_field->value) {
            stringbuffer_append_string(sb, my_field->key);
            stringbuffer_append_string(sb, " ");
            /* If this is null, then saving it as a space should
            * cause it to be null again.
            */
            if (my_field->value)
                stringbuffer_append_string(sb, my_field->value);
            stringbuffer_append_string(sb, "\n");
        }
    }
    /* We don't need to worry about the arch's extra fields - they
     * will get taken care of the object_copy() function.
     */

    if (op->name && op->name != op2->name) {
        ADD_STRINGLINE_ENTRY(sb, "name ", op->name);
    }
    if (op->name_pl && op->name_pl != op2->name_pl) {
        ADD_STRINGLINE_ENTRY(sb, "name_pl ", op->name_pl);
    }
    if (op->anim_suffix && op->anim_suffix != op2->anim_suffix) {
        ADD_STRINGLINE_ENTRY(sb, "anim_suffix ", op->anim_suffix);
    }
    if (op->custom_name && op->custom_name != op2->custom_name) {
        ADD_STRINGLINE_ENTRY(sb, "custom_name ", op->custom_name);
    }
    if (op->title && op->title != op2->title) {
        ADD_STRINGLINE_ENTRY(sb, "title ", op->title);
    }
    if (op->race && op->race != op2->race) {
        ADD_STRINGLINE_ENTRY(sb, "race ", op->race);
    }
    if (op->slaying && op->slaying != op2->slaying) {
        ADD_STRINGLINE_ENTRY(sb, "slaying ", op->slaying);
    }
    if (op->skill && op->skill != op2->skill) {
        ADD_STRINGLINE_ENTRY(sb, "skill ", op->skill);
    }
    if (op->msg && op->msg != op2->msg) {
        stringbuffer_append_string(sb, "msg\n");
        stringbuffer_append_string(sb, op->msg);
        stringbuffer_append_string(sb, "endmsg\n");
    }
    if (op->lore && op->lore != op2->lore) {
        stringbuffer_append_string(sb, "lore\n");
        stringbuffer_append_string(sb, op->lore);
        stringbuffer_append_string(sb, "endlore\n");
    }
    if (op->other_arch != op2->other_arch && op->other_arch != NULL && op->other_arch->name) {
        ADD_STRINGLINE_ENTRY(sb, "other_arch ", op->other_arch->name);
    }
    if (op->face != op2->face) {
        ADD_STRINGLINE_ENTRY(sb, "face ", op->face->name);
    }

    if (op->animation != op2->animation) {
        if (op->animation) {
            ADD_STRINGLINE_ENTRY(sb, "animation ", animations[GET_ANIM_ID(op)].name);
            if (!QUERY_FLAG (op, FLAG_ANIMATE)) {
                stringbuffer_append_string(sb, "is_animated 0\n");
            }
        } else {
            stringbuffer_append_string(sb, "animation NONE\n");
        }
    }
    if (op->stats.Str != op2->stats.Str)
        FAST_SAVE_LONG(sb, "Str ", op->stats.Str);
    if (op->stats.Dex != op2->stats.Dex)
        FAST_SAVE_LONG(sb, "Dex ", op->stats.Dex);
    if (op->stats.Con != op2->stats.Con)
        FAST_SAVE_LONG(sb, "Con ", op->stats.Con);
    if (op->stats.Wis != op2->stats.Wis)
        FAST_SAVE_LONG(sb, "Wis ", op->stats.Wis);
    if (op->stats.Pow != op2->stats.Pow)
        FAST_SAVE_LONG(sb, "Pow ", op->stats.Pow);
    if (op->stats.Cha != op2->stats.Cha)
        FAST_SAVE_LONG(sb, "Cha ", op->stats.Cha);
    if (op->stats.Int != op2->stats.Int)
        FAST_SAVE_LONG(sb, "Int ", op->stats.Int);
    if (op->stats.hp != op2->stats.hp)
        FAST_SAVE_LONG(sb, "hp ", op->stats.hp);
    if (op->stats.maxhp != op2->stats.maxhp)
        FAST_SAVE_LONG(sb, "maxhp ", op->stats.maxhp);
    if (op->stats.sp != op2->stats.sp)
        FAST_SAVE_LONG(sb, "sp ", op->stats.sp);
    if (op->stats.maxsp != op2->stats.maxsp)
        FAST_SAVE_LONG(sb, "maxsp ", op->stats.maxsp);
    if (op->stats.grace != op2->stats.grace)
        FAST_SAVE_LONG(sb, "grace ", op->stats.grace);
    if (op->stats.maxgrace != op2->stats.maxgrace)
        FAST_SAVE_LONG(sb, "maxgrace ", op->stats.maxgrace);

    if (op->stats.exp != op2->stats.exp) {
        snprintf(buf2, sizeof(buf2), "%"FMT64, op->stats.exp);
        ADD_STRINGLINE_ENTRY(sb, "exp ", buf2);
    }

    if (op->total_exp != op2->total_exp) {
        snprintf(buf2, sizeof(buf2), "%"FMT64, op->total_exp);
        ADD_STRINGLINE_ENTRY(sb, "total_exp ", buf2);
    }

    if (op->expmul != op2->expmul)
        FAST_SAVE_DOUBLE(sb, "expmul ", op->expmul);
    if (op->stats.food != op2->stats.food)
        FAST_SAVE_LONG(sb, "food ", op->stats.food);
    if (op->stats.dam != op2->stats.dam)
        FAST_SAVE_LONG(sb, "dam ", op->stats.dam);
    if (op->stats.luck != op2->stats.luck)
        FAST_SAVE_LONG(sb, "luck ", op->stats.luck);
    if (op->stats.wc != op2->stats.wc)
        FAST_SAVE_LONG(sb, "wc ", op->stats.wc);
    if (op->stats.ac != op2->stats.ac)
        FAST_SAVE_LONG(sb, "ac ", op->stats.ac);
    if (op->x != op2->x)
        FAST_SAVE_LONG(sb, "x ", op->x);
    if (op->y != op2->y)
        FAST_SAVE_LONG(sb, "y ", op->y);
    if (op->speed != op2->speed) {
        FAST_SAVE_DOUBLE(sb, "speed ", op->speed);
    }
    if (op->speed > 0 && op->speed_left != op2->speed_left) {
        FAST_SAVE_DOUBLE(sb, "speed_left ", op->speed_left);
    }
    if (op->weapon_speed != op2->weapon_speed) {
        FAST_SAVE_DOUBLE(sb, "weapon_speed ", op->weapon_speed);
    }
    if (op->weapon_speed > 0 && op->weapon_speed_left != op2->weapon_speed_left) {
        FAST_SAVE_DOUBLE(sb, "weapon_speed_left ", op->weapon_speed_left);
    }
    if (op->move_status != op2->move_status)
        FAST_SAVE_LONG(sb, "move_state ", op->move_status);
    if (op->attack_movement != op2->attack_movement)
        FAST_SAVE_LONG(sb, "attack_movement ", op->attack_movement);
    if (op->nrof != op2->nrof)
        FAST_SAVE_LONG(sb, "nrof ", op->nrof);
    if (op->level != op2->level)
        FAST_SAVE_LONG(sb, "level ", op->level);
    if (op->direction != op2->direction)
        FAST_SAVE_LONG(sb, "direction ", op->direction);
    if (op->type != op2->type)
        FAST_SAVE_LONG(sb, "type ", op->type);
    if (op->subtype != op2->subtype)
        FAST_SAVE_LONG(sb, "subtype ", op->subtype);
    if (op->attacktype != op2->attacktype)
        FAST_SAVE_LONG(sb, "attacktype ", op->attacktype);

    for (tmp = 0; tmp < NROFATTACKS; tmp++) {
        if (op->resist[tmp] != op2->resist[tmp]) {
            stringbuffer_append_string(sb, "resist_");
            FAST_SAVE_LONG(sb, resist_save[tmp], op->resist[tmp]);
        }
    }

    if (op->path_attuned != op2->path_attuned)
        FAST_SAVE_LONG(sb, "path_attuned ", op->path_attuned);
    if (op->path_repelled != op2->path_repelled)
        FAST_SAVE_LONG(sb, "path_repelled ", op->path_repelled);
    if (op->path_denied != op2->path_denied)
        FAST_SAVE_LONG(sb, "path_denied ", op->path_denied);
    if (op->material != op2->material)
        FAST_SAVE_LONG(sb, "material ", op->material);
    if (op->materialname && op->materialname != op2->materialname) {
        ADD_STRINGLINE_ENTRY(sb, "materialname ", op->materialname);
    }
    if (op->value != op2->value)
        FAST_SAVE_LONG(sb, "value ", op->value);
    if (op->carrying != op2->carrying)
        FAST_SAVE_LONG(sb, "carrying ", op->carrying);
    if (op->weight != op2->weight)
        FAST_SAVE_LONG(sb, "weight ", op->weight);
    if (op->invisible != op2->invisible)
        FAST_SAVE_LONG(sb, "invisible ", op->invisible);
    if (op->state != op2->state)
        FAST_SAVE_LONG(sb, "state ", op->state);
    if (op->magic != op2->magic)
        FAST_SAVE_LONG(sb, "magic ", op->magic);
    if (op->last_heal != op2->last_heal)
        FAST_SAVE_LONG(sb, "last_heal ", op->last_heal);
    if (op->last_sp != op2->last_sp)
        FAST_SAVE_LONG(sb, "last_sp ", op->last_sp);
    if (op->last_grace != op2->last_grace)
        FAST_SAVE_LONG(sb, "last_grace ", op->last_grace);
    if (op->last_eat != op2->last_eat)
        FAST_SAVE_LONG(sb, "last_eat ", op->last_eat);
    if (QUERY_FLAG(op, FLAG_IS_LINKED) && (tmp = get_button_value(op)))
        FAST_SAVE_LONG(sb, "connected ", tmp);
    if (op->glow_radius != op2->glow_radius)
        FAST_SAVE_LONG(sb, "glow_radius ", op->glow_radius);
    if (op->randomitems != op2->randomitems) {
        ADD_STRINGLINE_ENTRY(sb, "randomitems ", op->randomitems ? op->randomitems->name : "none");
    }

    if (op->run_away != op2->run_away)
        FAST_SAVE_LONG(sb, "run_away ", op->run_away);
    if (op->pick_up != op2->pick_up)
        FAST_SAVE_LONG(sb, "pick_up ", op->pick_up);
    if (op->weight_limit != op2->weight_limit)
        FAST_SAVE_LONG(sb, "container ", op->weight_limit);
    if (op->will_apply != op2->will_apply)
        FAST_SAVE_LONG(sb, "will_apply ", op->will_apply);
    if (op->smoothlevel != op2->smoothlevel)
        FAST_SAVE_LONG(sb, "smoothlevel ", op->smoothlevel);

    if (op->map_layer != op2->map_layer)
        ADD_STRINGLINE_ENTRY(sb, "map_layer ", map_layer_name[op->map_layer]);

    if (op->weapontype && op->weapontype != op2->weapontype) {
        FAST_SAVE_LONG(sb, "weapontype ", op->weapontype);
    }
    if (op->client_type && op->client_type != op2->client_type) {
        FAST_SAVE_LONG(sb, "client_type ", op->client_type);
    }

    if (op->item_power != op2->item_power) {
        FAST_SAVE_LONG(sb, "item_power ", op->item_power);
    }

    if (op->duration != op2->duration)
        FAST_SAVE_LONG(sb, "duration ", op->duration);

    if (op->range != op2->range)
        FAST_SAVE_LONG(sb, "range ", op->range);

    if (op->range_modifier != op2->range_modifier)
        FAST_SAVE_LONG(sb, "range_modifier ", op->range_modifier);

    if (op->duration_modifier != op2->duration_modifier)
        FAST_SAVE_LONG(sb, "duration_modifier ", op->duration_modifier);

    if (op->dam_modifier != op2->dam_modifier)
        FAST_SAVE_LONG(sb, "dam_modifier ", op->dam_modifier);

    if (op->gen_sp_armour != op2->gen_sp_armour) {
        FAST_SAVE_LONG(sb, "gen_sp_armour ", op->gen_sp_armour);
    }

    /* I've kept the old int move type saving code commented out.
     * In an ideal world, we'd know if we want to do a quick
     * save (say to a temp map, where we don't care about strings),
     * or a slower save/dm dump, where printing out strings is handy.
     */
    if (op->move_type != op2->move_type) {
        /*FAST_SAVE_LONG(sb, "move_type ", op->move_type)*/
        stringbuffer_append_string(sb, "move_type ");
        get_string_move_type(sb, op->move_type);
        stringbuffer_append_string(sb, "\n");
    }
    if (op->move_block != op2->move_block) {
        /*FAST_SAVE_LONG(sb, "move_block ", op->move_block)*/
        stringbuffer_append_string(sb, "move_block ");
        get_string_move_type(sb, op->move_block);
        stringbuffer_append_string(sb, "\n");
    }
    if (op->move_allow != op2->move_allow) {
        /*FAST_SAVE_LONG(sb, "move_allow ", op->move_allow);*/
        stringbuffer_append_string(sb, "move_allow ");
        get_string_move_type(sb, op->move_allow);
        stringbuffer_append_string(sb, "\n");
    }
    if (op->move_on != op2->move_on) {
        /*FAST_SAVE_LONG(sb, "move_on ", op->move_on);*/
        stringbuffer_append_string(sb, "move_on ");
        get_string_move_type(sb, op->move_on);
        stringbuffer_append_string(sb, "\n");
    }
    if (op->move_off != op2->move_off) {
        /*FAST_SAVE_LONG(sb, "move_off ", op->move_off);*/
        stringbuffer_append_string(sb, "move_off ");
        get_string_move_type(sb, op->move_off);
        stringbuffer_append_string(sb, "\n");
    }
    if (op->move_slow != op2->move_slow) {
        /*FAST_SAVE_LONG(sb, "move_slow ", op->move_slow);*/
        stringbuffer_append_string(sb, "move_slow ");
        get_string_move_type(sb, op->move_slow);
        stringbuffer_append_string(sb, "\n");
    }

    if (op->move_slow_penalty != op2->move_slow_penalty) {
        FAST_SAVE_DOUBLE(sb, "move_slow_penalty ", op->move_slow_penalty);
    }

    if (!COMPARE_FLAGS(op, op2)) {
        for (tmp = 0; tmp <= NUM_FLAGS; tmp++) {
            if (flag_names[tmp] && (QUERY_FLAG(op, tmp) != QUERY_FLAG(op2, tmp))) {
                ADD_STRINGLINE_ENTRY(sb, flag_names[tmp], QUERY_FLAG(op, tmp) ? " 1" : " 0");
            }
        }
    }

    /* Save body locations */
    for (i = 0; i < NUM_BODY_LOCATIONS; i++) {
        if (op->body_info[i] != op2->body_info[i]) {
            stringbuffer_append_string(sb, body_locations[i].save_name);
            FAST_SAVE_LONG(sb, " ", op->body_info[i]);
        }
    }

}

/**
 * Store a string representation of op in sb. Suitable for saving an object
 * to a file.
 */
void save_object_in_sb(StringBuffer *sb, const object *op, const int flag) {
    archetype *at = op->arch;
    if (at == NULL)
        at = empty_archetype;

    stringbuffer_append_printf(sb, "arch %s\n", at->name);

    if (op->arch->reference_count > 0) {
        /* The object is a custom item/monster, so we handle its save differently.
         * We compare the custom archetype to the "original" one, then only save hp/gr/sp
         * which are the only values we can't recompute later - all others are modified by items in inventory.
         * Note that hp/gr/sp will appear twice in save, but last value will take precedence.
         */
        archetype *original = find_archetype(op->arch->name);
        if (!original) {
            LOG(llevError, "could not find original archetype %s for custom monster!\n", op->arch->name);
            abort();
        }
        get_ob_diff(sb, &op->arch->clone, &original->clone);
        if (op->stats.hp != op->arch->clone.stats.hp)
            FAST_SAVE_LONG(sb, "hp ", op->stats.hp);
        if (op->stats.sp != op->arch->clone.stats.sp)
            FAST_SAVE_LONG(sb, "sp ", op->stats.sp);
        if (op->stats.grace != op->arch->clone.stats.grace)
            FAST_SAVE_LONG(sb, "grace ", op->stats.grace);
        if (op->x != op->arch->clone.x)
            FAST_SAVE_LONG(sb, "x ", op->x);
        if (op->y != op->arch->clone.y)
            FAST_SAVE_LONG(sb, "y ", op->y);
    } else if (op->artifact != NULL) {
    /* if op is an artifact, then find the "standard" artifact to use that for the diff */
        object *base;
        const artifact *artifact;

        artifact = find_artifact(op, op->artifact);
        if (artifact == NULL) {
            LOG(llevError, "could not find artifact %s [%d] to save data\n", op->artifact, op->type);
            get_ob_diff(sb, op, &at->clone);
        } else {
            stringbuffer_append_printf(sb, "artifact %s\n", op->artifact);
            base = arch_to_object(at);
            give_artifact_abilities(base, artifact->item);
            get_ob_diff(sb, op, base);
            object_free(base, FREE_OBJ_NO_DESTROY_CALLBACK | FREE_OBJ_FREE_INVENTORY);
        }
    } else {
        get_ob_diff(sb, op, &at->clone);
    }

    /* Eneq(@csd.uu.se): Added this to allow containers being saved with contents*/
    FOR_INV_PREPARE(op, tmp)
        save_object_in_sb(sb, tmp, flag);
    FOR_INV_FINISH();

    stringbuffer_append_string(sb, "end\n");
}

/**
 * Dumps all variables in an object to a file.
 *
 * @param fp
 * file to write to.
 * @param op
 * object to save.
 * @param flag
 * combination of @ref SAVE_FLAG_xxx "SAVE_FLAG_xxx" flags.
 * @return
 * one of @ref SAVE_ERROR_xxx "SAVE_ERROR_xxx" values.
 */
int save_object(FILE *fp, object *op, int flag) {
    /* Even if the object does have an owner, it would seem that we should
     * still save it.
     */
    if (object_get_owner(op) != NULL || fp == NULL)
        return SAVE_ERROR_OK;

    /* If it is unpaid and we don't want to save those, just return. */
    if (!(flag&SAVE_FLAG_SAVE_UNPAID) && (QUERY_FLAG(op, FLAG_UNPAID))) {
        return SAVE_ERROR_OK;
    }

    /* If the object has no_save set, just return */
    if (QUERY_FLAG(op, FLAG_NO_SAVE))
        return SAVE_ERROR_OK;

    StringBuffer *sb = stringbuffer_new();
    save_object_in_sb(sb, op, flag);
    char *cp = stringbuffer_finish(sb);
    if (fputs(cp, fp) == EOF) {
        free(cp);
        return SAVE_ERROR_WRITE;
    } else {
        free(cp);
        return SAVE_ERROR_OK;
    }
}