Read values from a binary file in C - c

Question

this is my problem: I don't know how to read the integers from a binary file. I need a solution for understand the problem behind the code.
This is the image of my binary file:
This is a format to memorize 32 bit integers in little endian. For example we have a file with 3 values: 1, 2 and 3, with this format they willl be codified in:
01 00 00 00 02 00 00 00 03 00 00 00 or 01 FF FF FF ... .
I wrote some line of code and I do not understand why it does not work. The debug don't give me errors.
This is my code
#include <stdlib.h>
#include <stdio.h>
int *leggiinteri2(const char *filename, size_t *size)
{
FILE *f;
int *p = NULL;
f = fopen(filename, "rb");
if (f == NULL) {
p = NULL;
}
else {
size_t nInteri = fread(size, sizeof(int), 1, f);
if (nInteri != 1) {
if (feof(f)) {
p = NULL;
}
if (ferror(f)) {
p = NULL;
}
}
else {
p = malloc(sizeof(int)*((int)size));
fseek(f, 0, SEEK_SET);
nInteri = fread(p, sizeof(int), *size, f);
if (nInteri != *size) {
if (feof(f)) {
p = NULL;
}
if (ferror(f)) {
p = NULL;
}
}
}
}
fclose(f);
return p;
}

Answer 1

Try some thing like:
fread (buffer, sizeof(char), 8, fid);
x = (s32)(((buffer[0]<<24) & 0xFF000000) + ((buffer[1]<<16) & 0x00FF0000)
+ ((buffer[2]<< 8) & 0x0000FF00) + ( buffer[3] & 0x000000FF));
I am not sure of the order (little or big endian). If KO, reverse the buffer indice 3, 2, 1, 0.

Answer 2

I finally found the solution, it took a lot of time but it was worth it, now I understand the logic behind it.
This is the code for those who need it:
#include <stdlib.h>
#include <stdio.h>
int *leggiinteri2(const char *filename, size_t *size)
{
FILE *f;
int *p = NULL;
f = fopen(filename, "rb");
if (f == NULL) {
p = NULL;
}
else {
fseek(f, 0, SEEK_END); //It tells me how many values ​​there are in
//the file, both those that I need and those
//that do not
long dim = ftell(f); // I assign to dim the value that tells me
//ftell, conditioned by the previous function
dim = dim / 4; //because I want the integer values (int = 4 bytes)
*size = dim;
p = malloc(sizeof(int) * dim);
fseek(f, 0, 0);
size_t n = fread(p, sizeof(int), *size, f);
if (n != *size) {
if (feof(f)) {
p = NULL;
}
if (ferror(f)) {
p = NULL;
}
}
if (n == 0) //serves to check for empty or NULL files
p = NULL;
}
fclose(f);
return p;
}