mirror of
https://codeberg.org/nsxiv/nsxiv
synced 2024-11-05 21:20:25 +00:00
135 lines
2.8 KiB
C
135 lines
2.8 KiB
C
/* Copyright 2012 Bert Muennich
|
|
*
|
|
* This file is part of sxiv.
|
|
*
|
|
* sxiv 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.
|
|
*
|
|
* sxiv 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 sxiv. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#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);
|
|
break;
|
|
}
|
|
}
|
|
|
|
close(fd);
|
|
return val;
|
|
|
|
abort:
|
|
close(fd);
|
|
return -1;
|
|
}
|