Hunk pattern stripper.

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

/* Strips even hunks out of a file. This is useful for files with duplicate patterns. */
/* Change HUNK_SIZE to change the size of the hunk. */

int main() {
#define HUNK_SIZE 4096

FILE *file = fopen("original.img", "rb");

if (file == NULL) {
    printf("Sorry, try again! \n");
    return 1;
}

fseek(file, 0, SEEK_END);
long int size = ftell(file);
fclose(file);

#define BUFFER_SIZE ((size + HUNK_SIZE) / 2)

uint8_t* buffer = malloc(sizeof(uint8_t)*size);
int bytes_read = fread(buffer, sizeof(uint8_t), size, file);
fclose(file);

uint8_t new_file[BUFFER_SIZE];
int size_new = sizeof(new_file); // We are using 8-bit unsigned ints, don't worry.

printf("Read original! New file size will be: %d. \n", size_new);

for (int i = 0; i <= ( ((size / HUNK_SIZE) - 1) / 2 ); ++i) {
    for (int j = 0; j <= (HUNK_SIZE - 1); ++j) {
        new_file[(i * HUNK_SIZE) + j] = buffer[((i * HUNK_SIZE) * 2) + j];
    }
}

FILE *nf = fopen("new.img", "wb");
fwrite(new_file, sizeof(uint8_t), size_new, nf);
fclose(nf);

printf("Read back a new image! \n");
return 0;
}