ref: 003395076f6428011f974028245bae80157f7578
dir: /src/z_native.c/
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005-2014 Simon Howard
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// DESCRIPTION:
// Zone Memory Allocation. Neat.
//
// This is an implementation of the zone memory API which
// uses native calls to malloc() and free().
//
#include <stdlib.h>
#include <string.h>
#include "z_zone.h"
#include "i_system.h"
#include "doomtype.h"
#define ZONEID 0x1d4a11
typedef struct memblock_s memblock_t;
struct memblock_s
{
int id; // = ZONEID
int tag;
int size;
void **user;
memblock_t *prev;
memblock_t *next;
};
// Linked list of allocated blocks for each tag type
static memblock_t *allocated_blocks[PU_NUM_TAGS];
#ifdef TESTING
static int test_malloced = 0;
void *test_malloc(size_t size)
{
int *result;
if (test_malloced + size > 2 * 1024 * 1024)
{
return NULL;
}
test_malloced += size;
result = malloc(size + sizeof(int));
*result = size;
return result + 1;
}
void test_free(void *data)
{
int *i;
i = ((int *) data) - 1;
test_malloced -= *i;
free(i);
}
#define malloc test_malloc
#define free test_free
#endif /* #ifdef TESTING */
// Add a block into the linked list for its type.
static void Z_InsertBlock(memblock_t *block)
{
block->prev = NULL;
block->next = allocated_blocks[block->tag];
allocated_blocks[block->tag] = block;
if (block->next != NULL)
{
block->next->prev = block;
}
}
// Remove a block from its linked list.
static void Z_RemoveBlock(memblock_t *block)
{
// Unlink from list
if (block->prev == NULL)
{
// Start of list
allocated_blocks[block->tag] = block->next;
}
else
{
block->prev->next = block->next;
}
if (block->next != NULL)
{
block->next->prev = block->prev;
}
}
//
// Z_Init
//
void Z_Init (void)
{
memset(allocated_blocks, 0, sizeof(allocated_blocks));
printf("zone memory: Using native C allocator.\n");
}
//
// Z_Free
//
void Z_Free (void* ptr)
{
memblock_t* block;
block = (memblock_t *) ((byte *)ptr - sizeof(memblock_t));
if (block->id != ZONEID)
{
I_Error ("Z_Free: freed a pointer without ZONEID");
}
if (block->tag != PU_FREE && block->user != NULL)
{
// clear the user's mark
*block->user = NULL;
}
Z_RemoveBlock(block);
// Free back to system
free(block);
}
// Empty data from the cache list to allocate enough data of the size
// required.
//
// Returns true if any blocks were freed.
static boolean ClearCache(int size)
{
memblock_t *block;
memblock_t *next_block;
int remaining;
block = allocated_blocks[PU_CACHE];
if (block == NULL)
{
// Cache is already empty.
return false;
}
// Search to the end of the PU_CACHE list. The blocks at the end
// of the list are the ones that have been free for longer and
// are more likely to be unneeded now.
while (block->next != NULL)
{
block = block->next;
}
//printf("out of memory; cleaning out the cache: %i\n", test_malloced);
// Search backwards through the list freeing blocks until we have
// freed the amount of memory required.
remaining = size;
while (remaining > 0)
{
if (block == NULL)
{
// No blocks left to free; we've done our best.
break;
}
next_block = block->prev;
Z_RemoveBlock(block);
remaining -= block->size;
if (block->user)
{
*block->user = NULL;
}
free(block);
block = next_block;
}
return true;
}
//
// Z_Malloc
// You can pass a NULL user if the tag is < PU_PURGELEVEL.
//
void *Z_Malloc(int size, int tag, void *user)
{
memblock_t *newblock;
unsigned char *data;
void *result;
if (tag < 0 || tag >= PU_NUM_TAGS || tag == PU_FREE)
{
I_Error("Z_Malloc: attempted to allocate a block with an invalid "
"tag: %i", tag);
}
if (user == NULL && tag >= PU_PURGELEVEL)
{
I_Error ("Z_Malloc: an owner is required for purgable blocks");
}
// Malloc a block of the required size
newblock = NULL;
while (newblock == NULL)
{
newblock = (memblock_t *) malloc(sizeof(memblock_t) + size);
if (newblock == NULL)
{
if (!ClearCache(sizeof(memblock_t) + size))
{
I_Error("Z_Malloc: failed on allocation of %i bytes", size);
}
}
}
newblock->tag = tag;
// Hook into the linked list for this tag type
newblock->id = ZONEID;
newblock->user = user;
newblock->size = size;
Z_InsertBlock(newblock);
data = (unsigned char *) newblock;
result = data + sizeof(memblock_t);
if (user != NULL)
{
*newblock->user = result;
}
return result;
}
//
// Z_FreeTags
//
void Z_FreeTags(int lowtag, int hightag)
{
int i;
for (i=lowtag; i<= hightag; ++i)
{
memblock_t *block;
memblock_t *next;
// Free all in this chain
for (block=allocated_blocks[i]; block != NULL; )
{
next = block->next;
// Free this block
if (block->user != NULL)
{
*block->user = NULL;
}
free(block);
// Jump to the next in the chain
block = next;
}
// This chain is empty now
allocated_blocks[i] = NULL;
}
}
//
// Z_DumpHeap
//
void Z_DumpHeap(int lowtag, int hightag)
{
// broken
#if 0
memblock_t* block;
printf ("zone size: %i location: %p\n",
mainzone->size,mainzone);
printf ("tag range: %i to %i\n",
lowtag, hightag);
for (block = mainzone->blocklist.next ; ; block = block->next)
{
if (block->tag >= lowtag && block->tag <= hightag)
printf ("block:%p size:%7i user:%p tag:%3i\n",
block, block->size, block->user, block->tag);
if (block->next == &mainzone->blocklist)
{
// all blocks have been hit
break;
}
if ( (byte *)block + block->size != (byte *)block->next)
printf ("ERROR: block size does not touch the next block\n");
if ( block->next->prev != block)
printf ("ERROR: next block doesn't have proper back link\n");
if (block->tag == PU_FREE && block->next->tag == PU_FREE)
printf ("ERROR: two consecutive free blocks\n");
}
#endif
}
//
// Z_FileDumpHeap
//
void Z_FileDumpHeap(FILE *f)
{
// broken
#if 0
memblock_t* block;
fprintf (f,"zone size: %i location: %p\n",mainzone->size,mainzone);
for (block = mainzone->blocklist.next ; ; block = block->next)
{
fprintf (f,"block:%p size:%7i user:%p tag:%3i\n",
block, block->size, block->user, block->tag);
if (block->next == &mainzone->blocklist)
{
// all blocks have been hit
break;
}
if ( (byte *)block + block->size != (byte *)block->next)
fprintf (f,"ERROR: block size does not touch the next block\n");
if ( block->next->prev != block)
fprintf (f,"ERROR: next block doesn't have proper back link\n");
if (block->tag == PU_FREE && block->next->tag == PU_FREE)
fprintf (f,"ERROR: two consecutive free blocks\n");
}
#endif
}
//
// Z_CheckHeap
//
void Z_CheckHeap (void)
{
memblock_t *block;
memblock_t *prev;
int i;
// Check all chains
for (i=0; i<PU_NUM_TAGS; ++i)
{
prev = NULL;
for (block=allocated_blocks[i]; block != NULL; block = block->next)
{
if (block->id != ZONEID)
{
I_Error("Z_CheckHeap: Block without a ZONEID!");
}
if (block->prev != prev)
{
I_Error("Z_CheckHeap: Doubly-linked list corrupted!");
}
prev = block;
}
}
}
//
// Z_ChangeTag
//
void Z_ChangeTag2(void *ptr, int tag, const char *file, int line)
{
memblock_t* block;
block = (memblock_t *) ((byte *)ptr - sizeof(memblock_t));
if (block->id != ZONEID)
I_Error("%s:%i: Z_ChangeTag: block without a ZONEID!",
file, line);
if (tag >= PU_PURGELEVEL && block->user == NULL)
I_Error("%s:%i: Z_ChangeTag: an owner is required "
"for purgable blocks", file, line);
// Remove the block from its current list, and rehook it into
// its new list.
Z_RemoveBlock(block);
block->tag = tag;
Z_InsertBlock(block);
}
void Z_ChangeUser(void *ptr, void **user)
{
memblock_t* block;
block = (memblock_t *) ((byte *)ptr - sizeof(memblock_t));
if (block->id != ZONEID)
{
I_Error("Z_ChangeUser: Tried to change user for invalid block!");
}
block->user = user;
*user = ptr;
}
//
// Z_FreeMemory
//
int Z_FreeMemory(void)
{
// Limited by the system??
return -1;
}
unsigned int Z_ZoneSize(void)
{
return 0;
}