最佳适应算法c语言

最佳适应算法是一种内存分配算法，它可以在已分配内存块中寻找最适合所需大小的空闲块进行分配，从而减少内存的碎片化。在C语言中，一种实现最佳适应算法的方式是使用链表来维护空闲块的信息，每次分配时遍历链表找到最小的合适块进行分配。同时，在释放内存时需要对相邻的空闲块进行合并以避免碎片化。以下是一段使用最佳适应算法的C语言代码示例：

struct block {
    int size;
    struct block *next;
};

struct block *free_list;

void *malloc(size_t size) {
    struct block *prev, *curr;
    void *result = NULL;
    curr = free_list;
    prev = NULL;
    while (curr != NULL) {
        if (curr->size >= size && (result == NULL || curr->size < ((struct block *)result)->size)) {
            result = curr;
        }
        prev = curr;
        curr = curr->next;
    }
    if (result != NULL) {
        if (((struct block *)result)->size > size + sizeof(struct block)) {
            struct block *new_block = (struct block *)((char *)result + size + sizeof(struct block));
            new_block->size = ((struct block *)result)->size - size - sizeof(struct block);
            new_block->next = ((struct block *)result)->next;
            if (prev == NULL) {
                free_list = new_block;
            } else {
                prev->next = new_block;
            }
        } else {
            if (prev == NULL) {
                free_list = ((struct block *)result)->next;
            } else {
                prev->next = ((struct block *)result)->next;
            }
        }
    }
    return result != NULL ? (char *)result + sizeof(struct block) : NULL;
}

void free(void *ptr) {
    struct block *prev, *curr;
    prev = NULL;
    curr = free_list;
    while (curr != NULL && curr != (struct block *)((char *)ptr - sizeof(struct block))) {
        prev = curr;
        curr = curr->next;
    }
    if (curr != NULL) {
        if (prev == NULL) {
            free_list = (struct block *)((char *)ptr - sizeof(struct block));
        } else {
            prev->next = (struct block *)((char *)ptr - sizeof(struct block));
        }
        ((struct block *)((char *)ptr - sizeof(struct block)))->next = curr->next;
        if (curr->next != NULL && (char *)curr->next == (char *)((struct block *)((char *)ptr - sizeof(struct block))) + ((struct block *)((char *)ptr - sizeof(struct block)))->size) {
            ((struct block *)((char *)ptr - sizeof(struct block)))->size += curr->next->size + sizeof(struct block);
            ((struct block *)((char *)ptr - sizeof(struct block)))->next = curr->next->next;
        }
        if (prev != NULL && (char *)prev + prev->size + sizeof(struct block) == (char *)((struct block *)((char *)ptr - sizeof(struct block)))) {
            prev->size += ((struct block *)((char *)ptr - sizeof(struct block)))->size + sizeof(struct block);
            prev->next = ((struct block *)((char *)ptr - sizeof(struct block)))->next;
        }
    }
}

以上代码仅供参考，实际使用时需要根据具体情况进行修改和完善。