diff options
Diffstat (limited to 'fiv-io.c')
| -rw-r--r-- | fiv-io.c | 41 |
1 files changed, 10 insertions, 31 deletions
@@ -4225,43 +4225,22 @@ fiv_io_orientation_apply(cairo_surface_t *surface, FivIoOrientation fiv_io_exif_orientation(const guint8 *tiff, gsize len) { - // libtiff also knows how to do this, but it's not a lot of code. // The "Orientation" tag/field is part of Baseline TIFF 6.0 (1992), // it just so happens that Exif is derived from this format. // There is no other meaningful placement for this than right in IFD0, // describing the main image. - const uint8_t *end = tiff + len, - le[4] = {'I', 'I', 42, 0}, - be[4] = {'M', 'M', 0, 42}; - - uint16_t (*u16)(const uint8_t *) = NULL; - uint32_t (*u32)(const uint8_t *) = NULL; - if (tiff + 8 > end) { - return FivIoOrientationUnknown; - } else if (!memcmp(tiff, le, sizeof le)) { - u16 = wuffs_base__peek_u16le__no_bounds_check; - u32 = wuffs_base__peek_u32le__no_bounds_check; - } else if (!memcmp(tiff, be, sizeof be)) { - u16 = wuffs_base__peek_u16be__no_bounds_check; - u32 = wuffs_base__peek_u32be__no_bounds_check; - } else { - return FivIoOrientationUnknown; - } - - const uint8_t *ifd0 = tiff + u32(tiff + 4); - if (ifd0 + 2 > end) + struct tiffer T = {}; + if (!tiffer_init(&T, tiff, len) || !tiffer_next_ifd(&T)) return FivIoOrientationUnknown; - uint16_t fields = u16(ifd0); - enum { BYTE = 1, ASCII, SHORT, LONG, RATIONAL, - SBYTE, UNDEFINED, SSHORT, SLONG, SRATIONAL, FLOAT, DOUBLE }; - enum { Orientation = 274 }; - for (const guint8 *p = ifd0 + 2; fields-- && p + 12 <= end; p += 12) { - uint16_t tag = u16(p), type = u16(p + 2), value16 = u16(p + 8); - uint32_t count = u32(p + 4); - if (G_UNLIKELY(tag == Orientation && type == SHORT && count == 1 && - value16 >= 1 && value16 <= 8)) - return value16; + struct tiffer_entry entry = {}; + while (tiffer_next_entry(&T, &entry)) { + int64_t orientation = 0; + if (G_UNLIKELY(entry.tag == TIFF_Orientation) && + entry.type == SHORT && entry.remaining_count == 1 && + tiffer_integer(&T, &entry, &orientation) && + orientation >= 1 && orientation <= 8) + return orientation; } return FivIoOrientationUnknown; } |