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/* $Cambridge: hermes/src/prayer/lib/list.c,v 1.3 2008/09/16 09:59:57 dpc22 Exp $ */
/************************************************
* Prayer - a Webmail Interface *
************************************************/
/* Copyright (c) University of Cambridge 2000 - 2008 */
/* See the file NOTICE for conditions of use and distribution. */
#include "lib.h"
/* list_create() *********************************************************
*
* Create a fresh list structure
* pool: Target pool for list and all list elements
* use_case: T => case is significant in _by_name operations.
************************************************************************/
struct list *list_create(struct pool *pool, BOOL use_case)
{
struct list *result = pool_alloc(pool, sizeof(struct list));
result->pool = pool;
result->use_case = use_case;
result->head = NIL;
result->tail = NIL;
result->length = 0L;
return (result);
}
/* list_free() ***********************************************************
*
* Free a list structure, including all list nodes. NOOP unless list
* has been allocated in the NIL pool.
************************************************************************/
void list_free(struct list *list)
{
struct list_item *current, *next;
if (list->pool) /* NOOP if pool */
return;
for (current = list->head; current; current = next) {
next = current->next;
free(current);
}
free(list);
}
/* list_length() *********************************************************
*
* Return current length of the list.
************************************************************************/
unsigned long list_length(struct list *list)
{
return (list->length);
}
/* ====================================================================== */
/* list_unshift() ********************************************************
*
* Add new entry to start of a list
* list:
* item: List item to add
* name: Name for this list item, if any
************************************************************************/
void list_unshift(struct list *list, struct list_item *item, char *name)
{
if (item == NIL)
item = pool_alloc(list->pool, sizeof(struct list_item));
item->next = NIL;
if (name)
item->name = pool_strdup(list->pool, name);
else
item->name = NIL;
if (list->head) {
item->next = list->head;
list->head = item;
} else {
item->next = NIL;
list->head = list->tail = item;
}
list->length++;
}
/* list_shift() **********************************************************
*
* Removes (but doesn't free) entry from the start of the list
* list:
*
* Returns: Ptr to list item which was removed.
************************************************************************/
struct list_item *list_shift(struct list *list)
{
struct list_item *item;
if (list->head == NIL)
return (NIL);
item = list->head;
if (list->head == list->tail)
list->head = list->tail = NIL; /* Remove single item from list */
else
list->head = list->head->next; /* Remove first item from list */
list->length--;
return (item);
}
/* ====================================================================== */
/* list_push() ***********************************************************
*
* Add an entry to the end of a list
* list:
* item: List item to push
* name: Name for new list item, if any.
************************************************************************/
void list_push(struct list *list, struct list_item *item, char *name)
{
if (item == NIL)
item = pool_alloc(list->pool, sizeof(struct list_item));
item->next = NIL;
if (name)
item->name = pool_strdup(list->pool, name);
else
item->name = NIL;
if (list->tail)
list->tail = list->tail->next = item;
else
list->head = list->tail = item;
list->length++;
}
/* list_pop() ************************************************************
*
* Removes (but doesn't free) entry from the end of a list
* list:
*
* Returns: Ptr to list item which was removed.
************************************************************************/
struct list_item *list_pop(struct list *list)
{
struct list_item *item;
if (list->head == NIL)
return (NIL);
if (list->head == list->tail) {
/* Remove single item from list */
item = list->head;
list->head = NIL;
list->tail = NIL;
} else {
struct list_item *last = list->head;
/* Find penultimate item on list: inefficient with single linked list! */
while (last->next)
last = last->next;
item = last->next;
last->next = NIL;
}
list->length--;
return (item);
}
/* ====================================================================== */
BOOL
list_insert_sorted(struct list * list, struct list_item * item, char *name)
{
struct list_item *last, *next;
if (item == NIL)
item = pool_alloc(list->pool, sizeof(struct list_item));
item->next = NIL;
if (name)
item->name = pool_strdup(list->pool, name);
else
item->name = NIL;
if (list->use_case) {
if (((next = list->head) == NIL) || (strcmp(next->name, name) > 0)) {
item->next = list->head; /* Insert at start of list */
list->head = item;
} else {
do {
last = next; /* (next != NIL) */
next = next->next;
}
while (next && (strcmp(next->name, name) < 0));
/* Add to this position in list */
item->next = next;
last->next = item;
}
} else {
if (((next = list->head) == NIL)
|| (strcasecmp(next->name, name) > 0)) {
item->next = list->head; /* Insert at start of list */
list->head = item;
} else {
do {
last = next; /* (next != NIL) */
next = next->next;
}
while (next && (strcasecmp(next->name, name) < 0));
/* Add to this position in list */
item->next = next;
last->next = item;
}
}
list->length++;
return (T);
}
/* ====================================================================== */
/* list_lookup_byname() **************************************************
*
* List lookup by name
* list:
* name: Name to look up.
*
* Returns: list item or NIL if not found
************************************************************************/
struct list_item *list_lookup_byname(struct list *list, char *name)
{
struct list_item *item;
if (list->use_case) {
for (item = list->head; item; item = item->next) {
if (item->name && !strcmp(item->name, name))
return (item);
}
} else {
for (item = list->head; item; item = item->next) {
if (item->name && !strcasecmp(item->name, name))
return (item);
}
}
return (NIL);
}
/* list_lookup_byoffset() ***********************************************
*
* List lookup by offset
* list:
* offset: Offset into list
*
* Returns: list item or NIL if offset is out of range
************************************************************************/
struct list_item *list_lookup_byoffset(struct list *list,
unsigned long offset)
{
struct list_item *item;
for (item = list->head; item; item = item->next) {
if (offset == 0)
return (item);
offset--;
}
return (NIL);
}
/* ====================================================================== */
/* list_free_item() ******************************************************
*
* Free single list item
* list:
* item: Item to remove
************************************************************************/
static void list_free_item(struct list *list, struct list_item *item)
{
if (list->pool)
return;
if (item->name)
free(item->name);
free(item);
}
/* list_remove_byname() **************************************************
*
* Remove named entry from list
* list:
* name: Name of entry to remove
*
* Returns: T on sucess, NIL otherwise
************************************************************************/
BOOL list_remove_byname(struct list *list, char *name)
{
struct list_item *last, *current;
/* Check for empty list? */
if (list->head == NIL)
return (NIL);
/* Remove from start of list? */
if (list->use_case) {
if ((list->head->name) && !strcmp(name, list->head->name)) {
current = list->head;
list->head = current->next;
/* Removed sole entry from list? */
if (current->next == NIL)
list->tail = NIL;
list_free_item(list, current);
list->length--;
return (T);
}
/* Remove from middle or end of list */
for (last = list->head; (current = last->next); last = current) {
if (current->name && !strcmp(current->name, name)) {
if ((last->next = current->next) == NIL)
list->tail = last; /* Removed last item in list */
list_free_item(list, current);
list->length--;
return (T);
}
}
return (NIL);
}
if ((list->head->name) && !strcasecmp(name, list->head->name)) {
current = list->head;
list->head = current->next;
/* Removed sole entry from list? */
if (current->next == NIL)
list->tail = NIL;
list_free_item(list, current);
list->length--;
return (T);
}
/* Remove from middle or end of list */
for (last = list->head; (current = last->next); last = current) {
if (current->name && !strcasecmp(current->name, name)) {
if ((last->next = current->next) == NIL)
list->tail = last; /* Removed last item in list */
list_free_item(list, current);
list->length--;
return (T);
}
}
return (NIL);
}
/* list_remove_byoffset() ************************************************
*
* Remove list entry by offset
* list:
* offset: List offset to remove
*
* Returns: T on success, NIl otherwise
************************************************************************/
BOOL list_remove_byoffset(struct list * list, unsigned long offset)
{
struct list_item *current, *last;
/* Check for empty list? */
if (list->head == NIL)
return (NIL);
/* Remove from start of list? */
if (offset == 0) {
current = list->head;
list->head = current->next;
/* Removed sole entry from list? */
if (list->head == NIL)
list->tail = NIL;
list_free_item(list, current);
list->length--;
return (T);
}
offset--;
/* Remove from middle or end of list */
for (last = list->head; (current = last->next); last = current) {
if (offset == 0) {
if ((last->next = current->next) == NIL)
list->tail = last; /* Removed last item in list */
list_free_item(list, current);
list->length--;
return (T);
}
offset--;
}
return (NIL);
}
/* ====================================================================== */
/* list_rename_item() ****************************************************
*
* Rename a list item
* list:
* oldname: Name of entry to rename
* newname: New name for entry
*
* Returns: T on success, NIL otherwise
************************************************************************/
BOOL list_rename_item(struct list * list, char *oldname, char *newname)
{
struct list_item *current;
if (list->use_case) {
for (current = list->head; current; current = current->next) {
if (!strcmp(current->name, oldname)) {
free(current->name);
current->name = pool_strdup(NIL, newname);
return (T);
}
}
return (NIL);
}
for (current = list->head; current; current = current->next) {
if (!strcasecmp(current->name, oldname)) {
free(current->name);
current->name = pool_strdup(NIL, newname);
return (T);
}
}
return (NIL);
}
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