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#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <endian.h>
int
main(int argc, char *argv[])
{
if (argc != 5) {
fprintf(stderr, "Usage: %s LATTE FRAPPE MACCHIATO MOCHA\n", argv[0]);
return 1;
}
FILE *images[4];
uint32_t headers[16];
for (int i = 0; i < 4; i++) {
images[i] = fopen(argv[i+1], "r");
if (!images[i]) {
perror(argv[i+1]);
return 1;
}
if (fread(&headers + i*16, 16, 1, images[i]) != 1 || memcmp(&headers, &headers + i*16, 16)) {
fprintf(stderr, "error: header mismatch");
return 1;
}
}
uint32_t width = be32toh(headers[2]);
uint32_t height = be32toh(headers[3]);
char *buf = calloc(width, 8);
fwrite(&headers, 16, 1, stdout);
for (uint32_t row = 0; row < height; row++) {
for (int i = 0; i < 4; i++) {
if (fread(buf, 8, width, images[i]) != width) {
if (ferror(images[i])) {
perror("fread");
} else {
perror("fread: unexpected EOF");
}
return 1;
}
uint32_t start = width / 4 * i + width / 8 - width / 4 * row / height;
uint32_t end = start + width / 4;
if (i == 0) start = 0;
if (i == 3) end = width;
fwrite(buf + 8 * start, 8, end - start, stdout);
}
}
return 0;
}
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