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Clean up

This commit is contained in:
Přemysl Eric Janouch 2023-05-28 08:50:32 +02:00
parent 33251eaca7
commit d5b2e43364
Signed by: p
GPG Key ID: A0420B94F92B9493
1 changed files with 10 additions and 31 deletions
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41
fiv-io.c
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@ -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;
}