固定块内存池c语言实现

/** fpool.h (fixed memory pool)* author: xinghun_4*/#ifndef _FPOOL_H#define _FPOOL_Hint mem_pool_init(int base_size, int links);void mem_pool_destroy(void);void print_mem_pool_info(void);void *mem_malloc(int size);void mem_free(void *ptr);#endif 

测试代码没怎么写

/** fpool.c (fixed memory pool)* author: xinghun_4*/#include <stdio.h>#include <stdlib.h>#include <string.h>#include "fpool.h"#define MEM_POOL_DEBUG#define DEFAULT_BASE_SIZE 4#define DEFAULT_LINKS 4#define DEFAULT_BLOCKS 4#define DEFAULT_INCREMENT_LINKS 4#define DEFAULT_INCREMENT_BLOCKS 4#define ALIGN(ADD, SIZE) (((ADD) + ((SIZE) - 1)) & ~((SIZE) - 1))/* 声明内存块, 前向引用 */typedef struct _mem_block mem_block_t;/* 内存节点指针 */typedef union _mem_node{mem_block_t *b_next; /* 指向下一块内存节点 */char data[1]; /* 内存节点首地址 */}mem_node_t;/* 内存块 */struct _mem_block{short index; /* 内存链索引, mem_free 的时候有用 */mem_node_t n_node; /* 内存节点 */char pad[2];};/* 内存链 */typedef struct _mem_link{struct _mem_link *l_next; /* 指向下一条内存链 */short index; /* 内存链索引 */short blocks; /* 内存链内存块数 */short free_blocks; /* 内存链空闲内存块数 */char pad[2];mem_block_t *b_head; /* 内存链首内存块 */}mem_link_t;/* 内存池 */typedef struct _mem_pool{short links; /* 内存链数 */short base_size; /* 内存节点为base_size的倍数 */mem_link_t *l_head; /* 首内存链 */mem_link_t *l_tail; /* 尾内存链 */}mem_pool_t;static mem_pool_t mem_pool;/* add new memory links to our memory pool */static int add_mem_link(int links);/* add new memory blocks to our memory link */static int add_mem_block(mem_link_t *link, int blocks);/** @base_size: 节点大小单位* @links: 内存链条数*/int mem_pool_init(int base_size, int links){if(base_size <= 0){base_size = DEFAULT_BASE_SIZE;}else{/* base_size 为 4 的倍数 */base_size = ALIGN(base_size, DEFAULT_BASE_SIZE);}if(links <= 0){ links = DEFAULT_LINKS;}/* initiate mem_pool */ memset(&mem_pool, 0, sizeof(mem_pool));mem_pool.base_size = base_size;/* add links into the memory pool */if(!add_mem_link(links)){fprintf(stderr, "mem_pool_init::add_mem_link error/n");return 0;}return 1;}void mem_pool_destroy(void){mem_link_t *cur_l;mem_block_t *cur_b;cur_l = mem_pool.l_head;while(cur_l){/* 释放内存链 */mem_pool.l_head = mem_pool.l_head->l_next; /* 指向下一条内存链 */cur_b = cur_l->b_head;while(cur_b){/* 释放所有内存块 */cur_l->b_head = cur_l->b_head->n_node.b_next; /* 指向下个内存块 */free(cur_b);cur_b = cur_l->b_head;}cur_l = mem_pool.l_head;}memset(&mem_pool, 0, sizeof(mem_pool_t));}void print_mem_pool_info(void){int i;mem_link_t *cur_l = NULL;mem_block_t *cur_b = NULL;cur_l = mem_pool.l_head;if(NULL == cur_l){printf("/nmemory pool is not exist!/n");return;}/* memory pool info */printf("/n/************** Memory pool information **************//n");#ifdef MEM_POOL_DEBUGprintf("sizeof(mem_node_t) : %d/n", sizeof(mem_node_t));printf("sizeof(mem_block_t) : %d/n", sizeof(mem_block_t));printf("sizeof(mem_link_t) : %d/n", sizeof(mem_link_t));printf("sizeof(mem_pool_t) : %d/n", sizeof(mem_pool_t));#endifprintf("links : %d/n", mem_pool.links);printf("base_size : %d/n", mem_pool.base_size);printf("link head pointer : %x(%d)/n", (int)mem_pool.l_head, (int)mem_pool.l_head);printf("link tail pointer : %x(%d)/n", (int)mem_pool.l_tail, (int)mem_pool.l_tail);while(cur_l){/* 打印内存链 */printf("/n#### memory link %d ####/n", cur_l->index);printf("blocks : %d/n", cur_l->blocks);printf("free blocks : %d/n", cur_l->free_blocks);printf("block size : %d/n", cur_l->index * mem_pool.base_size);printf("block head pointer : %x(%d)/n", (int)cur_l->b_head, (int)cur_l->b_head);cur_b = cur_l->b_head;i = 0;while(cur_b){printf("memory block %d : %x(%d)/n", i++, (int)cur_b, (int)cur_b);cur_b = cur_b->n_node.b_next;}cur_l = cur_l->l_next;}printf("/*****************************************************//n");}void *mem_malloc(int size){int align_size = ALIGN(size, mem_pool.base_size);int index = align_size / mem_pool.base_size - 1;mem_link_t *cur_l = mem_pool.l_head;mem_block_t *cur_b = NULL;mem_node_t *cur_n = NULL;int i;short *p_index;if(index >= mem_pool.links){printf("no such size(%d) memory block!/n", align_size);return NULL;}/* go to the right link */for(i = 0; i < index; ++i){cur_l = cur_l->l_next;}if(0 >= cur_l->free_blocks){/* no free blocks, expand memory link */if(!add_mem_block(cur_l, DEFAULT_INCREMENT_BLOCKS)){fprintf(stderr, "mem_malloc::add_mem_block error/n");return NULL;}}/* get free block from block head pointer */cur_b = cur_l->b_head;cur_l->free_blocks--;/* modify memory link node head pointer */cur_l->b_head = cur_l->b_head->n_node.b_next;p_index = (short *)cur_b;/* 记录索引, 便于 mem_free 找到正确的内存链 */*p_index = cur_l->index;++p_index;cur_n = (mem_node_t *)p_index;return (void *)&(cur_n->data[0]);}void mem_free(void *ptr){short *p_index = (short *)ptr;mem_link_t *cur_l = mem_pool.l_head;mem_block_t *cur_b = NULL;int i;--p_index;/* go to the right link */for(i = 0; i < *p_index; ++i){cur_l = cur_l->l_next;}cur_b = (mem_block_t *)p_index;/* 内存链头部插入空闲内存块 */cur_b->n_node.b_next = cur_l->b_head;cur_l->b_head = cur_b;cur_l->free_blocks++;}/* 返回成功添加的内存链条数 */static int add_mem_link(int links){mem_link_t *new_l = NULL;int index = 0;int i = links;int cnt = 0;/* 求得新添加链的索引 */if(NULL == mem_pool.l_head){index = 0;}else{index = mem_pool.l_tail->index + 1;}while(i--){if(NULL == (new_l = (mem_link_t *)malloc(sizeof(mem_link_t)))){fprintf(stderr, "add_mem_link::malloc mem_link_t error/n");continue;}/* 初始化新内存链 */memset(new_l, 0, sizeof(mem_link_t));new_l->index = index++;/* 新内存链加入内存池 */if(NULL == mem_pool.l_head){mem_pool.l_head = new_l;mem_pool.l_tail = new_l;}else{mem_pool.l_tail->l_next = new_l;mem_pool.l_tail = new_l;}mem_pool.links++;++cnt;if(!add_mem_block(new_l, DEFAULT_INCREMENT_BLOCKS)){fprintf(stderr, "add_mem_link::add_mem_block error/n");}}return cnt;}static int add_mem_block(mem_link_t *link, int blocks){mem_block_t *new_b = NULL;int i = blocks;int cnt = 0;if(NULL == link){fprintf(stderr, "memory link is NULL!/n");return 0;}#ifdef MEM_POOL_DEBUGprintf("add_mem_block::block_size: %d/n", sizeof(short) + mem_pool.base_size * (link->index + 1));#endifwhile(i--){if(NULL == (new_b = (mem_block_t *)malloc(sizeof(short) + mem_pool.base_size * (link->index + 1)))){fprintf(stderr, "add_mem_block::malloc mem_block_t error/n");continue;}/* 初始化新内存块 */memset(new_b, 0, sizeof(mem_block_t));new_b->index = link->index;/* 新内存块加入内存链 */if(NULL == link->b_head){link->b_head = new_b;}else{new_b->n_node.b_next = link->b_head;link->b_head = new_b;}link->blocks++;link->free_blocks++;++cnt;}return cnt;}

 /** test.c (fixed memory pool test)* author: xinghun_4*/#include <stdio.h>#include <stdlib.h>#include "fpool.h"void mempool_test_index0(void){ int *t1 = (int *)mem_malloc(sizeof(int)); int *t2 = NULL; int value = 3; if(NULL == t1) {printf("mempool_test_index0:: mem_malloc t1 NULL/n"); return; } print_mem_pool_info(); if(NULL == (t2 = (int *)mem_malloc(sizeof(int)))) {printf("mempool_test_index0:: mem_malloc t2 NULL/n");return; } print_mem_pool_info(); *t1 = value; printf("mempool_test01:: t1: %d/n", *t1); *t1 *= *t1; *t2 = *t1; (*t2)++; printf("mempool_test01:: t1: %d/n", *t1); printf("mempool_test01:: t2: %d/n", *t2); mem_free(t1); t1 = NULL; /* 不要忘了, 否则若两指针同时指向一块内存会出问题 */ print_mem_pool_info(); mem_free(t2); t2 = NULL; print_mem_pool_info();}int main(int agrc, char **argv){ if(!mem_pool_init(0, 0)){return -1;}print_mem_pool_info();mempool_test_index0();mem_pool_destroy();print_mem_pool_info();system("pause");return 0;}