使用数据结构处理内存的个人 malloc 函数

Question

我有这个函数，只有当它可用并且请求的字节数的大小适合我的小型托管内存时，它才会分配并发送回多个字节。 我的问题：

没有分配适当的数据结构，恐怕我不会得到正确的地址。有谁知道我如何在另一个程序中使用它作为库来测试这个函数？

数据结构

typedef struct memBlock{
struct memBlock* next;
unsigned long size;  // Size of this block
unsigned int is_used;  // bool 0 = not used 1 = used
} memBlock;

MALLOC 函数：

char *mm_alloc(unsigned long no_of_chars){

if (!has_initialized) {
    printf("No Memory has been intialized, PLEASE INITIALIZE THE MEMORY BEFORE calling This function\n");
    exit(1);
}


void *cur_location; // this is where we are currentl in our memory pool

memBlock *current_loc_mb; // the current mem block location

char *mem_location; // mem location we will return to the user

/* We are going to have to include the size of our data struct when we are searching for open memory*/
no_of_chars = no_of_chars + sizeof(struct memBlock);

mem_location = 0; // set to 0 until a proper size has been found

cur_location = managed_memory_start; // start at the beginning of our allocated memory

// go until there is no more memory left, allocate until we get to the end of our managed memory
while (managed_memory_start != NULL) {

    /*cur_location and cur_loc_mcb are at the same address initially,
but we use the current location as a pointer to move around our managed memory*/

    cur_loc_mcb = (memBlock *)cur_location; 

    // if our current location is not used
        if (!cur_loc_mcb->is_used) {

            if (cur_loc_mcb->size >= no_of_chars) {

                // we have found a size big enough or equal to what the user asks for
                cur_loc_mcb->is_used = 1; 
                mem_location = cur_location; 

                break;

            }
        }

// at this point we dont have a size big enough, move to the next one
cur_location = cur_location + cur_loc_mcb->size; 

}
/*Move the memory past or MCB and return*/

mem_location = mem_location + sizeof(struct memBlock);

return mem_location;
}

Answer 1

你在代码中的某个地方设置了 mem_location

            mem_location = cur_location;

然后，在返回它的值之前，你改变它

    mem_location = mem_location + sizeof(struct memBlock);

好像不太对劲……