ref: 82132ad618b5c6de247568a3a026367799ff3d96
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, 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; }