BLI_mempool.c

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/*
 *
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2008 by Blender Foundation.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/*
        Simple, fast memory allocator for allocating many elements of the same size.
*/

#include "MEM_guardedalloc.h"
#include "BLI_blenlib.h"
#include "BLI_mempool.h"
#include <string.h> 

typedef struct BLI_freenode{
        struct BLI_freenode *next;
}BLI_freenode;

typedef struct BLI_mempool_chunk{
        struct BLI_mempool_chunk *next, *prev;
        void *data;
}BLI_mempool_chunk;

typedef struct BLI_mempool{
        struct ListBase chunks;
        int esize, csize, pchunk;               /*size of elements and chunks in bytes and number of elements per chunk*/
        struct BLI_freenode     *free;          /*free element list. Interleaved into chunk datas.*/
        int totalloc, totused; /*total number of elements allocated in total, and currently in use*/
        int use_sysmalloc;
}BLI_mempool;

BLI_mempool *BLI_mempool_create(int esize, int tote, int pchunk, int use_sysmalloc)
{       BLI_mempool  *pool = NULL;
        BLI_freenode *lasttail = NULL, *curnode = NULL;
        int i,j, maxchunks;
        char *addr;
        
        if (esize < sizeof(void*))
                esize = sizeof(void*);
        
        /*allocate the pool structure*/
        pool = use_sysmalloc ? malloc(sizeof(BLI_mempool)) : MEM_mallocN(sizeof(BLI_mempool), "memory pool");
        pool->esize = esize;
        pool->use_sysmalloc = use_sysmalloc;
        pool->pchunk = pchunk;  
        pool->csize = esize * pchunk;
        pool->chunks.first = pool->chunks.last = NULL;
        pool->totused= 0;
        
        maxchunks = tote / pchunk + 1;
        
        /*allocate the actual chunks*/
        for(i=0; i < maxchunks; i++){
                BLI_mempool_chunk *mpchunk = use_sysmalloc ? malloc(sizeof(BLI_mempool_chunk)) : MEM_mallocN(sizeof(BLI_mempool_chunk), "BLI_Mempool Chunk");
                mpchunk->next = mpchunk->prev = NULL;
                mpchunk->data = use_sysmalloc ? malloc(pool->csize) : MEM_mallocN(pool->csize, "BLI Mempool Chunk Data");
                BLI_addtail(&(pool->chunks), mpchunk);
                
                if(i==0) pool->free = mpchunk->data; /*start of the list*/
                /*loop through the allocated data, building the pointer structures*/
                for(addr = mpchunk->data, j=0; j < pool->pchunk; j++){
                        curnode = ((BLI_freenode*)addr);
                        addr += pool->esize;
                        curnode->next = (BLI_freenode*)addr;
                }
                /*final pointer in the previously allocated chunk is wrong.*/
                if(lasttail) lasttail->next = mpchunk->data;
                /*set the end of this chunks memoryy to the new tail for next iteration*/
                lasttail = curnode;

                pool->totalloc += pool->pchunk;
        }
        /*terminate the list*/
        curnode->next = NULL;
        return pool;
}
void *BLI_mempool_alloc(BLI_mempool *pool){
        void *retval=NULL;
        BLI_freenode *curnode=NULL;
        char *addr=NULL;
        int j;

        pool->totused++;

        if(!(pool->free)){
                /*need to allocate a new chunk*/
                BLI_mempool_chunk *mpchunk = pool->use_sysmalloc ? malloc(sizeof(BLI_mempool_chunk)) :  MEM_mallocN(sizeof(BLI_mempool_chunk), "BLI_Mempool Chunk");
                mpchunk->next = mpchunk->prev = NULL;
                mpchunk->data = pool->use_sysmalloc ? malloc(pool->csize) : MEM_mallocN(pool->csize, "BLI_Mempool Chunk Data");
                BLI_addtail(&(pool->chunks), mpchunk);

                pool->free = mpchunk->data; /*start of the list*/
                for(addr = mpchunk->data, j=0; j < pool->pchunk; j++){
                        curnode = ((BLI_freenode*)addr);
                        addr += pool->esize;
                        curnode->next = (BLI_freenode*)addr;
                }
                curnode->next = NULL; /*terminate the list*/

                pool->totalloc += pool->pchunk;
        }

        retval = pool->free;
        pool->free = pool->free->next;
        //memset(retval, 0, pool->esize);
        return retval;
}

void *BLI_mempool_calloc(BLI_mempool *pool){
        void *retval=NULL;
        retval = BLI_mempool_alloc(pool);
        memset(retval, 0, pool->esize);
        return retval;
}


void BLI_mempool_free(BLI_mempool *pool, void *addr){ //doesnt protect against double frees, dont be stupid!
        BLI_freenode *newhead = addr;
        BLI_freenode *curnode=NULL;
        char *tmpaddr=NULL;
        int i;

        newhead->next = pool->free;
        pool->free = newhead;

        pool->totused--;

        /*nothing is in use; free all the chunks except the first*/
        if (pool->totused == 0) {
                BLI_mempool_chunk *mpchunk=NULL, *first;

                first = pool->chunks.first;
                BLI_remlink(&pool->chunks, first);

                for(mpchunk = pool->chunks.first; mpchunk; mpchunk = mpchunk->next) {
                        if(pool->use_sysmalloc) free(mpchunk->data);
                        else                                    MEM_freeN(mpchunk->data);
                }

                pool->use_sysmalloc ? BLI_freelist(&(pool->chunks)) : BLI_freelistN(&(pool->chunks));
                
                BLI_addtail(&pool->chunks, first);
                pool->totalloc = pool->pchunk;

                pool->free = first->data; /*start of the list*/
                for(tmpaddr = first->data, i=0; i < pool->pchunk; i++){
                        curnode = ((BLI_freenode*)tmpaddr);
                        tmpaddr += pool->esize;
                        curnode->next = (BLI_freenode*)tmpaddr;
                }
                curnode->next = NULL; /*terminate the list*/
        }
}

void BLI_mempool_destroy(BLI_mempool *pool)
{
        BLI_mempool_chunk *mpchunk=NULL;
        if(pool->use_sysmalloc) {
                for(mpchunk = pool->chunks.first; mpchunk; mpchunk = mpchunk->next) {
                        free(mpchunk->data);
                }
                BLI_freelist(&(pool->chunks));
                free(pool);
        }
        else {
                for(mpchunk = pool->chunks.first; mpchunk; mpchunk = mpchunk->next) {
                        MEM_freeN(mpchunk->data);
                }
                BLI_freelistN(&(pool->chunks));
                MEM_freeN(pool);
        }
}