#define DEBUG
#include <stdlib.h>
#include <string.h>
#include "../include/mem.h"
int mem_is_zero(const void *ptr, size_t nbytes) {
    assert(ptr);
    assert(nbytes > 0);
    static const unsigned char zero_block[1024] = {0}; 
    while (nbytes >= sizeof(zero_block)) {
        if (memcmp(ptr, zero_block, sizeof(zero_block)) != 0)
            return 0;
        ptr = (const unsigned char *)ptr + sizeof(zero_block);
        nbytes -= sizeof(zero_block);
    }
    if (nbytes > 0 && memcmp(ptr, zero_block, nbytes) != 0)
        return 0;
    return 1;
}

int main(void){
    size_t nbytes = 4096;
    
    void *tmp = malloc(nbytes);
    memset(tmp, 0xAB, nbytes);
    free(tmp);
    
    void *ptr = ALLOC(nbytes);  // likely gets the same region back
    assert(!mem_is_zero(ptr, nbytes));  // FAILS — 0xAB still there
    assert(ptr != NULL);
    return EXIT_SUCCESS;
}