Thread: Memory Pool Question

Using this simple algorithm when you append a character into a string will reduce calls to [m|re|c]alloc...

Code:

typedef struct
{
    char *value;
    size_t length;
    size_t allocated;

} string;

void str_append(string *str, char c)
{
    if((str->length + 2) > str->allocated)
    {
        str->allocated += 255;
        str->value = realloc(str->value, str->allocated);
    }

    str->value[str->length] = c;
    str->value[++(str->length)] = 0;
}

I want to implement this algorithm to make a simple memory pool. But the problem is, when I use realloc, the returned memory address might be changed is possible...

Code:

function pool_request(MemoryPool pool_obj, number size)

    if pool_obj.length + size > pool_obj.allocated

        pool_obj.allocated += 255
        pool_obj.allocation = realloc(pool_obj.allocation, pool_obj.allocated)

    end if

    pool_obj.length += size

    return pointer operation:(pool_obj.allocation + (pool_obj.length - size))

end function

It seems the pseudocode above is impossible.