From fc0479232da65ca60119b6131a11e6aca4273d11 Mon Sep 17 00:00:00 2001
From: rain1 <rain1@openmailbox.org>
Date: Fri, 8 Apr 2016 13:08:47 +0000
Subject: [PATCH] Added crop tool.

---
 Makefile |   2 +-
 ffcrop.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 ffcrop.c

diff --git a/Makefile b/Makefile
index 21b82d9..bf5b40f 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@
 # See LICENSE file for copyright and license details
 include config.mk
 
-BIN = png2ff ff2png jpg2ff ff2jpg ff2ppm
+BIN = png2ff ff2png jpg2ff ff2jpg ff2ppm ffcrop
 SCRIPTS = 2ff
 SRC = ${BIN:=.c}
 HDR = arg.h
diff --git a/ffcrop.c b/ffcrop.c
new file mode 100644
index 0000000..03e162c
--- /dev/null
+++ b/ffcrop.c
@@ -0,0 +1,107 @@
+/* See LICENSE file for copyright and license details. */
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <png.h>
+
+static char *argv0;
+
+int
+main(int argc, char *argv[])
+{
+	size_t rowlen;
+	uint32_t hdr[4], width, height, i, tmp32;
+	uint16_t *row;
+	uint32_t crop_x, crop_y, crop_w, crop_h;
+	size_t crop_skiplen, crop_rowlen;
+
+	argv0 = argv[0], argc--, argv++;
+
+	if (argc != 4) {
+		fprintf(stderr, "usage: %s x y w h\n", argv0);
+		return 1;
+	}
+
+	crop_x = strtol(argv[0], NULL, 10);
+	crop_y = strtol(argv[1], NULL, 10);
+	crop_w = strtol(argv[2], NULL, 10);
+	crop_h = strtol(argv[3], NULL, 10);
+
+	/* header */
+	if (fread(hdr, sizeof(*hdr), 4, stdin) != 4) {
+		goto readerr;
+	}
+	if (memcmp("farbfeld", hdr, sizeof("farbfeld") - 1)) {
+		fprintf(stderr, "%s: invalid magic value\n", argv0);
+		return 1;
+	}
+	width = ntohl(hdr[2]);
+	height = ntohl(hdr[3]);
+
+	/* sanitize the input sizes */
+	if (crop_x > width) {
+		crop_x = width;
+	}
+        if (crop_y > height) {
+                crop_y = height;
+        }
+	if (crop_w > width - crop_x) {
+		crop_w = width - crop_x;
+	}
+	if (crop_h > height - crop_y) {
+		crop_h = height - crop_y;
+	}
+
+        /* write header */
+        fputs("farbfeld", stdout);
+        tmp32 = htonl(crop_w);
+        if (fwrite(&tmp32, sizeof(uint32_t), 1, stdout) != 1)
+                goto writerr;
+        tmp32 = htonl(crop_h);
+        if (fwrite(&tmp32, sizeof(uint32_t), 1, stdout) != 1)
+                goto writerr;
+
+	if (width > SIZE_MAX / ((sizeof("RGBA") - 1) * sizeof(uint16_t))) {
+		fprintf(stderr, "%s: row length integer overflow\n", argv0);
+		return 1;
+	}
+	rowlen = width * (sizeof("RGBA") - 1);
+	if (!(row = malloc(rowlen * sizeof(uint16_t)))) {
+		fprintf(stderr, "%s: malloc: out of memory\n", argv0);
+		return 1;
+	}
+	crop_skiplen = crop_x * (sizeof("RGBA") - 1);
+	crop_rowlen = crop_w * (sizeof("RGBA") - 1);
+
+	/* skip the first rows */
+	for (i = 0; i < crop_y; ++i) {
+		if (fread(row, sizeof(uint16_t), rowlen, stdin) != rowlen) {
+			goto readerr;
+		}
+	}
+	/* write rows */
+	for (i = 0; i < crop_h; ++i) {
+		if (fread(row, sizeof(uint16_t), rowlen, stdin) != rowlen) {
+			goto readerr;
+		}
+		fwrite(row + crop_skiplen, sizeof(uint16_t), crop_rowlen, stdout);
+	}
+
+	return 0;
+readerr:
+	fprintf(stderr, "%s: fread: ", argv0);
+	perror(NULL);
+
+	return 1;
+
+writerr:
+	fprintf(stderr, "%s: fwrite: ", argv0);
+	perror(NULL);
+
+	return 1;
+}
-- 
2.8.1