Question

我有这个函数，只有当它可用且所请求的字节数的大小适合我的小型管理内存时才会分配和发回许多字节。我的问题：

没有分配适当的数据结构，我担心我不会收回正确的地址。有谁知道如何使用它作为另一个程序中的库来测试这个函数？

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功能：

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

在代码中的某处设置mem_location

            mem_location = cur_location;

以后，在返回其值之前，您需要更改它

    mem_location = mem_location + sizeof(struct memBlock);

这似乎不对......

使用数据结构处理内存的个人malloc函数

1 个答案: