Added own exif tag handling in files exif.[ch]

Makefile

@@ -8,7 +8,7 @@ LIBS    = -lX11 -lImlib2 -lgif
 PREFIX    = /usr/local
 MANPREFIX = $(PREFIX)/share/man
 
-SRC = commands.c image.c main.c options.c thumbs.c util.c window.c
+SRC = commands.c exif.c image.c main.c options.c thumbs.c util.c window.c
 OBJ = $(SRC:.c=.o)
 
 all: options sxiv

exif.c

@@ -0,0 +1,131 @@
+/* sxiv: exif.c
+ * Copyright (c) 2011 Bert Muennich <be.muennich at googlemail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#define _POSIX_C_SOURCE 200112L
+
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "exif.h"
+#include "util.h"
+
+ssize_t s_read(int fd, const char *fn, void *buf, size_t n) {
+	ssize_t ret;
+
+	ret = read(fd, buf, n);
+	if (ret < n) {
+		warn("unexpected end-of-file: %s", fn);
+		return -1;
+	} else {
+		return ret;
+	}
+}
+
+unsigned short btous(unsigned char *buf, byteorder_t order) {
+	if (buf == NULL)
+		return 0;
+	if (order == BO_BIG_ENDIAN)
+		return buf[0] << 8 | buf[1];
+	else
+		return buf[1] << 8 | buf[0];
+}
+
+unsigned int btoui(unsigned char *buf, byteorder_t order) {
+	if (buf == NULL)
+		return 0;
+	if (order == BO_BIG_ENDIAN)
+		return buf[0] << 24 | buf[1] << 16 | buf[2] << 8 | buf[3];
+	else
+		return buf[3] << 24 | buf[2] << 16 | buf[1] << 8 | buf[0];
+}
+
+int exif_orientation(const fileinfo_t *file) {
+	int fd;
+	unsigned char data[EXIF_MAX_LEN];
+	byteorder_t order = BO_BIG_ENDIAN;
+	unsigned int cnt, len, idx, val;
+
+	if (file == NULL || file->path == NULL)
+		return -1;
+
+	fd = open(file->path, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	if (s_read(fd, file->name, data, 4) < 0)
+		goto abort;
+	if (btous(data, order) != JPEG_MARKER_SOI)
+		goto abort;
+	if (btous(data + 2, order) != JPEG_MARKER_APP1)
+		goto abort;
+
+	if (s_read(fd, file->name, data, 2) < 0)
+		goto abort;
+	len = btous(data, order);
+	if (len < 8)
+		goto abort;
+
+	if (s_read(fd, file->name, data, 6) < 0)
+		goto abort;
+	if (btoui(data, order) != EXIF_HEAD)
+		goto abort;
+
+	len -= 8;
+	if (len < 12 || len > EXIF_MAX_LEN)
+		goto abort;
+	if (s_read(fd, file->name, data, len) < 0)
+		goto abort;
+
+	switch (btous(data, order)) {
+		case EXIF_BO_BIG_ENDIAN:
+			order = BO_BIG_ENDIAN;
+			break;
+		case EXIF_BO_LITTLE_ENDIAN:
+			order = BO_LITTLE_ENDIAN;
+			break;
+		default:
+			goto abort;
+			break;
+	}
+
+	if (btous(data + 2, order) != EXIF_TAG_MARK)
+		goto abort;
+	idx = btoui(data + 4, order);
+	if (idx > len - 2)
+		goto abort;
+
+	val = 0;
+	cnt = btous(data + idx, order);
+
+	for (idx += 2; cnt > 0 && idx < len - 12; cnt--, idx += 12) {
+		if (btous(data + idx, order) == EXIF_TAG_ORIENTATION) {
+			val = btous(data + idx + 8, order);
+			printf("exif orientation: %s: %u\n", file->name, val);
+			break;
+		}
+	}
+
+	close(fd);
+	return val;
+
+abort:
+	close(fd);
+	return -1;
+}

exif.h

@@ -0,0 +1,41 @@
+/* sxiv: exif.h
+ * Copyright (c) 2011 Bert Muennich <be.muennich at googlemail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef EXIF_H
+#define EXIF_H
+
+#include "types.h"
+
+enum {
+	JPEG_MARKER_SOI  = 0xFFD8,
+	JPEG_MARKER_APP1 = 0xFFE1
+};
+
+enum {
+	EXIF_MAX_LEN          = 0x10000,
+	EXIF_HEAD             = 0x45786966,
+	EXIF_BO_BIG_ENDIAN    = 0x4D4D,
+	EXIF_BO_LITTLE_ENDIAN = 0x4949,
+	EXIF_TAG_MARK         = 0x002A,
+	EXIF_TAG_ORIENTATION  = 0x0112
+};
+
+int exif_orientation(const fileinfo_t*);
+void exif_auto_orientate(const fileinfo_t*); /* in image.c */
+
+#endif /* EXIF_H */

image.c

@@ -25,6 +25,7 @@
 #include <unistd.h>
 #include <gif_lib.h>
 
+#include "exif.h"
 #include "image.h"
 #include "options.h"
 #include "util.h"
@@ -64,6 +65,34 @@ void img_init(img_t *img, win_t *win) {
 	img->multi.animate = false;
 }
 
+void exif_auto_orientate(const fileinfo_t *file) {
+	switch (exif_orientation(file)) {
+		case 5:
+			imlib_image_orientate(1);
+		case 2:
+			imlib_image_flip_vertical();
+			break;
+
+		case 3:
+			imlib_image_orientate(2);
+			break;
+
+		case 7:
+			imlib_image_orientate(1);
+		case 4:
+			imlib_image_flip_horizontal();
+			break;
+
+		case 6:
+			imlib_image_orientate(1);
+			break;
+
+		case 8:
+			imlib_image_orientate(3);
+			break;
+	}
+}
+
 bool img_load_gif(img_t *img, const fileinfo_t *file) {
 	GifFileType *gif;
 	GifRowType *rows = NULL;
@@ -254,6 +283,8 @@ bool img_load(img_t *img, const fileinfo_t *file) {
 		warn("could not open image: %s", file->name);
 		return false;
 	}
+	if (STREQ(fmt, "jpeg"))
+		exif_auto_orientate(file);
 	if (STREQ(fmt, "gif"))
 		img_load_gif(img, file);
 

thumbs.c

@@ -26,6 +26,7 @@
 #include <unistd.h>
 #include <utime.h>
 
+#include "exif.h"
 #include "thumbs.h"
 #include "util.h"
 #include "config.h"
@@ -254,6 +255,8 @@ bool tns_load(tns_t *tns, int n, const fileinfo_t *file,
 		imlib_free_image_and_decache();
 		return false;
 	}
+	if (STREQ(fmt, "jpeg"))
+		exif_auto_orientate(file);
 
 	w = imlib_image_get_width();
 	h = imlib_image_get_height();

types.h

@@ -6,6 +6,11 @@ typedef enum {
 	true
 } bool;
 
+typedef enum {
+	BO_BIG_ENDIAN,
+	BO_LITTLE_ENDIAN
+} byteorder_t;
+
 typedef enum {
 	MODE_IMAGE,
 	MODE_THUMB