/* Copyright (C) 1993, 1995, 1996 Aladdin Enterprises.  All rights reserved.
  
  This file is part of GNU Ghostscript.
  
  GNU Ghostscript is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility to
  anyone for the consequences of using it or for whether it serves any
  particular purpose or works at all, unless he says so in writing.  Refer to
  the GNU General Public License for full details.
  
  Everyone is granted permission to copy, modify and redistribute GNU
  Ghostscript, but only under the conditions described in the GNU General
  Public License.  A copy of this license is supposed to have been given to
  you along with GNU Ghostscript so you can know your rights and
  responsibilities.  It should be in a file named COPYING.  Among other
  things, the copyright notice and this notice must be preserved on all
  copies.
  
  Aladdin Enterprises is not affiliated with the Free Software Foundation or
  the GNU Project.  GNU Ghostscript, as distributed by Aladdin Enterprises,
  does not depend on any other GNU software.
*/

/* ialloc.c */
/* Memory allocator for Ghostscript interpreter */
#include "gx.h"
#include "memory_.h"
#include "errors.h"
#include "gsstruct.h"
#include "gxarith.h"			/* for small_exact_log2 */
#include "iref.h"			/* must precede iastate.h */
#include "iastate.h"
#include "ivmspace.h"
#include "store.h"

/*
 * Define global and local instances.
 */
gs_dual_memory_t gs_imemory;

/* Imported from gsalloc.c */
gs_ref_memory_t *ialloc_alloc_state(P2(gs_memory_t *, uint));

#define imem ((gs_ref_memory_t *)mem)

/* Initialize the allocator */
void
ialloc_init(gs_memory_t *mem, uint chunk_size, bool level2)
{	gs_ref_memory_t *ilmem = ialloc_alloc_state(mem, chunk_size);
	gs_ref_memory_t *igmem =
		(level2 ?
		 ialloc_alloc_state(mem, chunk_size) :
		 ilmem);
	gs_ref_memory_t *ismem = ialloc_alloc_state(mem, chunk_size);
	int i;

	for ( i = 0; i < countof(gs_imemory.spaces.indexed); i++ )
	  gs_imemory.spaces.indexed[i] = 0;
	gs_imemory.space_local = ilmem;
	gs_imemory.space_global = igmem;
	gs_imemory.space_system = ismem;
	gs_imemory.reclaim = 0;
	/* Level 1 systems have only local VM. */
	igmem->space = avm_global;
	ilmem->space = avm_local;	/* overrides if ilmem == igmem */
	igmem->global = ilmem->global = igmem;
	ismem->space = avm_system;
	ialloc_set_space(&gs_imemory, avm_global);
}

/* ================ Local/global VM ================ */

/* Get the space attribute of an allocator */
uint
imemory_space(gs_ref_memory_t *iimem)
{	return iimem->space;
}

/* Select the allocation space. */
void
ialloc_set_space(gs_dual_memory_t *dmem, uint space)
{	gs_ref_memory_t *mem = dmem->spaces.indexed[space >> r_space_shift];
	dmem->current = mem;
	dmem->current_space = mem->space;
}

/* Reset the requests. */
void
ialloc_reset_requested(gs_dual_memory_t *dmem)
{	dmem->space_system->gc_status.requested = 0;
	dmem->space_global->gc_status.requested = 0;
	dmem->space_local->gc_status.requested = 0;
}

/* ================ Refs ================ */

/*
 * As noted in iastate.h, every run of refs has an extra ref at the end
 * to hold relocation information for the garbage collector;
 * since sizeof(ref) % obj_align_mod == 0, we never need to
 * allocate any additional padding space at the end of the block.
 */
		
/* Allocate an array of refs. */
int
gs_alloc_ref_array(gs_ref_memory_t *mem, ref *parr, uint attrs,
  uint num_refs, client_name_t cname)
{	ref *obj;
	/* If we're allocating a run of refs already, */
	/* and we aren't about to overflow the maximum run length, use it. */
	if ( mem->cc.rtop == mem->cc.cbot &&
	     num_refs < (mem->cc.ctop - mem->cc.cbot) / sizeof(ref) &&
	     mem->cc.rtop - (byte *)mem->cc.rcur + num_refs * sizeof(ref) <
	       max_size_st_refs
	   )
	  {	obj = (ref *)mem->cc.rtop - 1;	/* back up over last ref */
		if_debug4('A', "[a%d:+$ ]%s(%u) = 0x%lx\n", imem->space,
			  client_name_string(cname), num_refs, (ulong)obj);
		mem->cc.rcur[-1].o_size += num_refs * sizeof(ref);
		  {	ref *end = (ref *)(mem->cc.rtop = mem->cc.cbot +=
					     num_refs * sizeof(ref));
			make_mark(end - 1);
		  }
	  }
	else
	  {	/*
		 * Allocate a new run.  We have to distinguish 3 cases:
		 *	- Same chunk: pcc unchanged, end == cc.cbot.
		 *	- Large chunk: pcc unchanged, end != cc.cbot.
		 *	- New chunk: pcc changed.
		 */
		chunk_t *pcc = mem->pcc;
		ref *end;
		obj = gs_alloc_struct_array((gs_memory_t *)mem, num_refs + 1,
					    ref, &st_refs, cname);
		if ( obj == 0 )
		  return_error(e_VMerror);
		/* Set the terminating ref now. */
		end = (ref *)obj + num_refs;
		make_mark(end);
		/* Set has_refs in the chunk. */
		if ( mem->pcc != pcc || mem->cc.cbot == (byte *)(end + 1) )
		  {	/* Ordinary chunk. */
			mem->cc.rcur = (obj_header_t *)obj;
			mem->cc.rtop = (byte *)(end + 1);
			mem->cc.has_refs = true;
		  }
		else
		  {	/* Large chunk. */
			/* This happens only for very large arrays, */
			/* so it doesn't need to be cheap. */
			chunk_locator_t cl;
			cl.memory = mem;
			cl.cp = mem->clast;
			chunk_locate_ptr(obj, &cl);
			cl.cp->has_refs = true;
		  }
	  }
	make_array(parr, attrs | mem->space, num_refs, obj);
	return 0;
}

/* Resize an array of refs.  Currently this is only implemented */
/* for shrinking, not for growing. */
int
gs_resize_ref_array(gs_ref_memory_t *mem, ref *parr,
  uint new_num_refs, client_name_t cname)
{	uint old_num_refs = r_size(parr);
	uint diff;
	ref *obj = parr->value.refs;
	if ( new_num_refs > old_num_refs || !r_has_type(parr, t_array) )
	  return_error(e_Fatal);
	diff = old_num_refs - new_num_refs;
	/* Check for LIFO.  See gs_free_ref_array for more details. */
	if ( mem->cc.rtop == mem->cc.cbot &&
	     (byte *)(obj + (old_num_refs + 1)) == mem->cc.rtop
	   )
	  {	/* Shorten the refs object. */
		ref *end = (ref *)(mem->cc.cbot = mem->cc.rtop -=
				     diff * sizeof(ref));
		if_debug4('A', "[a%d:<$ ]%s(%u) 0x%lx\n", imem->space,
			  client_name_string(cname), diff, (ulong)obj);
		mem->cc.rcur[-1].o_size -= diff * sizeof(ref);
		make_mark(end - 1);
	  }
	else
	  {	/* Punt. */
		if_debug4('A', "[a%d:<$#]%s(%u) 0x%lx\n", imem->space,
			  client_name_string(cname), diff, (ulong)obj);
		imem->lost.refs += diff * sizeof(ref);
	  }
	r_set_size(parr, new_num_refs);
	return 0;
}

/* Deallocate an array of refs.  Only do this if LIFO, or if */
/* the array occupies an entire chunk by itself. */
void
gs_free_ref_array(gs_ref_memory_t *mem, ref *parr, client_name_t cname)
{	uint num_refs = r_size(parr);
	ref *obj = parr->value.refs;
	/*
	 * Compute the storage size of the array, and check for LIFO
	 * freeing or a separate chunk.  Note that the array might be packed;
	 * for the moment, if it's anything but a t_array, punt.
	 * The +1s are for the extra ref for the GC.
	 */
	if ( !r_has_type(parr, t_array) )
	  ;		/* don't look for special cases */
	else if ( mem->cc.rtop == mem->cc.cbot &&
		  (byte *)(obj + (num_refs + 1)) == mem->cc.rtop
		)
	  {	if ( (obj_header_t *)obj == mem->cc.rcur )
		  {	/* Deallocate the entire refs object. */
			gs_free_object((gs_memory_t *)mem, obj, cname);
			mem->cc.rcur = 0;
			mem->cc.rtop = 0;
		  }
		else
		  {	/* Deallocate it at the end of the refs object. */
			if_debug4('A', "[a%d:-$ ]%s(%u) 0x%lx\n",
				  imem->space, client_name_string(cname),
				  num_refs, (ulong)obj);
			mem->cc.rcur[-1].o_size -= num_refs * sizeof(ref);
			mem->cc.rtop = mem->cc.cbot = (byte *)(obj + 1);
			make_mark(obj);
		  }
		return;
	  }
	else if ( num_refs >= (mem->large_size / arch_sizeof_ref - 1) )
	  {	/* See if this array has a chunk all to itself. */
		/* We only make this check when freeing very large objects, */
		/* so it doesn't need to be cheap. */
		chunk_locator_t cl;
		cl.memory = imem;
		cl.cp = imem->clast;
		if ( chunk_locate_ptr(obj, &cl) &&
		     obj == (ref *)((obj_header_t *)(cl.cp->cbase) + 1) &&
		     (byte *)(obj + (num_refs + 1)) == cl.cp->cend
		   )
		  {	/* Free the chunk. */
			if_debug4('a', "[a%d:-$L]%s(%u) 0x%lx\n",
				  imem->space, client_name_string(cname),
				  num_refs, (ulong)obj);
			alloc_free_chunk(cl.cp, imem);
			return;
		  }
	  }
	/* Punt. */
	if_debug4('A', "[a%d:-$#]%s(%u) 0x%lx\n", imem->space,
		  client_name_string(cname), num_refs, (ulong)obj);
	imem->lost.refs += num_refs * sizeof(ref);
}

/* Allocate a string ref. */
int
gs_alloc_string_ref(gs_ref_memory_t *mem, ref *psref,
  uint attrs, uint nbytes, client_name_t cname)
{	byte *str = gs_alloc_string((gs_memory_t *)mem, nbytes, cname);
	if ( str == 0 )
	  return_error(e_VMerror);
	make_string(psref, attrs | mem->space, nbytes, str);
	return 0;
}