1 files changed, 50 insertions, 0 deletions
diff --git a/bin/ff-catwalk.c b/bin/ff-catwalk.c
new file mode 100644
index 0000000..69b827e
--- /dev/null
+++ b/bin/ff-catwalk.c
@@ -0,0 +1,50 @@
+#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;
+}