118 lines
4 KiB
C
118 lines
4 KiB
C
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/* Emacs style mode select -*- C++ -*-
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*-----------------------------------------------------------------------------
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*
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*
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* PrBoom a Doom port merged with LxDoom and LSDLDoom
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* based on BOOM, a modified and improved DOOM engine
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* Copyright (C) 1999 by
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* id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
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* Copyright (C) 1999-2000 by
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* Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*
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* DESCRIPTION:
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* This is designed to be a fast allocator for small, regularly used block sizes
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*-----------------------------------------------------------------------------
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*/
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#include "doomtype.h"
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#include "z_zone.h"
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#include "z_bmalloc.h"
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#include "i_system.h"
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#include "rockmacros.h"
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typedef struct bmalpool_s {
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struct bmalpool_s *nextpool;
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size_t blocks;
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byte used[0];
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} bmalpool_t;
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inline static void* getelem(bmalpool_t *p, size_t size, size_t n)
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{
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return (((byte*)p) + sizeof(bmalpool_t) + sizeof(byte)*(p->blocks) + size*n);
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}
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inline static int iselem(const bmalpool_t *pool, size_t size, const void* p)
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{
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// CPhipps - need portable # of bytes between pointers
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int dif = (const char*)p - (const char*)pool;
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dif -= sizeof(bmalpool_t);
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dif -= pool->blocks;
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if (dif<0) return -1;
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dif /= size;
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return (((size_t)dif >= pool->blocks) ? -1 : dif);
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}
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enum { unused_block = 0, used_block = 1};
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void* Z_BMalloc(struct block_memory_alloc_s *pzone)
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{
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register bmalpool_t **pool = (bmalpool_t **)&(pzone->firstpool);
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while (*pool != NULL) {
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byte *p = memchr((*pool)->used, unused_block, (*pool)->blocks); // Scan for unused marker
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if (p) {
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int n = p - (*pool)->used;
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#ifdef SIMPLECHECKS
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if ((n<0) || ((size_t)n>=(*pool)->blocks))
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I_Error("Z_BMalloc: memchr returned pointer outside of array");
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#endif
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(*pool)->used[n] = used_block;
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return getelem(*pool, pzone->size, n);
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} else
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pool = &((*pool)->nextpool);
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}
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{
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// Nothing available, must allocate a new pool
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bmalpool_t *newpool;
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// CPhipps: Allocate new memory, initialised to 0
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*pool = newpool = Z_Calloc(sizeof(*newpool) + (sizeof(byte) + pzone->size)*(pzone->perpool),
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1, pzone->tag, NULL);
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newpool->nextpool = NULL; // NULL = (void*)0 so this is redundant
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// Return element 0 from this pool to satisfy the request
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newpool->used[0] = used_block;
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newpool->blocks = pzone->perpool;
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return getelem(newpool, pzone->size, 0);
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}
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}
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void Z_BFree(struct block_memory_alloc_s *pzone, void* p)
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{
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register bmalpool_t **pool = (bmalpool_t**)&(pzone->firstpool);
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while (*pool != NULL) {
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int n = iselem(*pool, pzone->size, p);
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if (n >= 0) {
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#ifdef SIMPLECHECKS
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if ((*pool)->used[n] == unused_block)
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I_Error("Z_BFree: Refree in zone %s", pzone->desc);
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#endif
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(*pool)->used[n] = unused_block;
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if (memchr(((*pool)->used), used_block, (*pool)->blocks) == NULL) {
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// Block is all unused, can be freed
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bmalpool_t *oldpool = *pool;
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*pool = (*pool)->nextpool;
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Z_Free(oldpool);
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}
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return;
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} else pool = &((*pool)->nextpool);
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}
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I_Error("Z_BFree: Free not in zone %s", pzone->desc);
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}
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