aboutsummaryrefslogtreecommitdiff
path: root/tools/info.h
diff options
context:
space:
mode:
Diffstat (limited to 'tools/info.h')
-rw-r--r--tools/info.h1265
1 files changed, 1265 insertions, 0 deletions
diff --git a/tools/info.h b/tools/info.h
new file mode 100644
index 0000000..1872345
--- /dev/null
+++ b/tools/info.h
@@ -0,0 +1,1265 @@
+//
+// info.h: metadata extraction utilities
+//
+// Copyright (c) 2021, Přemysl Eric Janouch <p@janouch.name>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+
+#include <jv.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+
+// --- Utilities ---------------------------------------------------------------
+
+static char *
+binhex(const uint8_t *data, size_t len)
+{
+ static const char *alphabet = "0123456789abcdef";
+ char *buf = calloc(1, len * 2 + 1), *p = buf;
+ for (size_t i = 0; i < len; i++) {
+ *p++ = alphabet[data[i] >> 4];
+ *p++ = alphabet[data[i] & 0xF];
+ }
+ return buf;
+}
+
+static uint32_t
+u32be(const uint8_t *p)
+{
+ return (uint32_t) p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3];
+}
+
+static uint16_t
+u16be(const uint8_t *p)
+{
+ return (uint16_t) p[0] << 8 | p[1];
+}
+
+static uint32_t
+u32le(const uint8_t *p)
+{
+ return (uint32_t) p[3] << 24 | p[2] << 16 | p[1] << 8 | p[0];
+}
+
+static uint16_t
+u16le(const uint8_t *p)
+{
+ return (uint16_t) p[1] << 8 | p[0];
+}
+
+// --- TIFF --------------------------------------------------------------------
+// TIFF Revision 6.0 (1992)
+// https://www.adobe.io/content/dam/udp/en/open/standards/tiff/TIFF6.pdf
+//
+// TIFF Technical Note 1: TIFF Trees (1993)
+// https://download.osgeo.org/libtiff/old/TTN1.ps
+//
+// DRAFT TIFF Technical Note 2 (1995)
+// https://www.awaresystems.be/imaging/tiff/specification/TIFFTechNote2.txt
+//
+// Adobe PageMaker 6.0 TIFF Technical Notes (1995) [includes TTN1]
+// https://www.adobe.io/content/dam/udp/en/open/standards/tiff/TIFFPM6.pdf
+//
+// Adobe Photoshop TIFF Technical Notes (2002)
+// https://www.adobe.io/content/dam/udp/en/open/standards/tiff/TIFFphotoshop.pdf
+// - Note that ImageSourceData 8BIM frames are specified differently
+// from how Adobe XMP Specification Part 3 defines them.
+// - The document places a condition on SubIFDs, without further explanation.
+//
+// Adobe Photoshop TIFF Technical Note 3 (2005)
+// http://chriscox.org/TIFFTN3d1.pdf
+//
+// Exif Version 2.3 (2012)
+// https://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf
+//
+// Exif Version 2.32 (2019)
+// https://www.cipa.jp/e/std/std-sec.html
+//
+// libtiff is a mess, and the format is not particularly complicated.
+// Exiv2 is senselessly copylefted, and cannot do much.
+// libexif is only marginally better.
+// ExifTool is too user-oriented.
+
+static struct un {
+ uint32_t (*u32) (const uint8_t *);
+ uint16_t (*u16) (const uint8_t *);
+} unbe = {u32be, u16be}, unle = {u32le, u16le};
+
+struct tiffer {
+ struct un *un;
+ const uint8_t *begin, *p, *end;
+ uint16_t remaining_fields;
+};
+
+static bool
+tiffer_u32(struct tiffer *self, uint32_t *u)
+{
+ if (self->p + 4 > self->end)
+ return false;
+ *u = self->un->u32(self->p);
+ self->p += 4;
+ return true;
+}
+
+static bool
+tiffer_u16(struct tiffer *self, uint16_t *u)
+{
+ if (self->p + 2 > self->end)
+ return false;
+ *u = self->un->u16(self->p);
+ self->p += 2;
+ return true;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static bool
+tiffer_init(struct tiffer *self, const uint8_t *tiff, size_t len)
+{
+ self->un = NULL;
+ self->begin = self->p = tiff;
+ self->end = tiff + len;
+ self->remaining_fields = 0;
+
+ const uint8_t
+ le[4] = {'I', 'I', 42, 0},
+ be[4] = {'M', 'M', 0, 42};
+
+ if (tiff + 8 > self->end)
+ return false;
+ else if (!memcmp(tiff, le, sizeof le))
+ self->un = &unle;
+ else if (!memcmp(tiff, be, sizeof be))
+ self->un = &unbe;
+ else
+ return false;
+
+ self->p = tiff + 4;
+ // The first IFD needs to be read by caller explicitly,
+ // even though it's required to be present by TIFF 6.0.
+ return true;
+}
+
+/// Read the next IFD in a sequence.
+static bool
+tiffer_next_ifd(struct tiffer *self)
+{
+ // All fields from any previous IFD need to be read first.
+ if (self->remaining_fields)
+ return false;
+
+ uint32_t ifd_offset = 0;
+ if (!tiffer_u32(self, &ifd_offset))
+ return false;
+
+ // There is nothing more to read, this chain has terminated.
+ if (!ifd_offset)
+ return false;
+
+ // Note that TIFF 6.0 requires there to be at least one entry,
+ // but there is no need for us to check it.
+ self->p = self->begin + ifd_offset;
+ return tiffer_u16(self, &self->remaining_fields);
+}
+
+/// Initialize a derived TIFF reader for a subIFD at the given location.
+static bool
+tiffer_subifd(struct tiffer *self, uint32_t offset, struct tiffer *subreader)
+{
+ *subreader = *self;
+ subreader->p = subreader->begin + offset;
+ return tiffer_u16(subreader, &subreader->remaining_fields);
+}
+
+enum tiffer_type {
+ BYTE = 1, ASCII, SHORT, LONG, RATIONAL,
+ SBYTE, UNDEFINED, SSHORT, SLONG, SRATIONAL, FLOAT, DOUBLE,
+ IFD // This last type from TIFF Technical Note 1 isn't really used much.
+};
+
+static size_t
+tiffer_value_size(enum tiffer_type type)
+{
+ switch (type) {
+ case BYTE:
+ case SBYTE:
+ case ASCII:
+ case UNDEFINED:
+ return 1;
+ case SHORT:
+ case SSHORT:
+ return 2;
+ case LONG:
+ case SLONG:
+ case FLOAT:
+ case IFD:
+ return 4;
+ case RATIONAL:
+ case SRATIONAL:
+ case DOUBLE:
+ return 8;
+ default:
+ return 0;
+ }
+}
+
+/// A lean iterator for values within entries.
+struct tiffer_entry {
+ uint16_t tag;
+ enum tiffer_type type;
+ // For {S,}BYTE, ASCII, UNDEFINED, use these fields directly.
+ const uint8_t *p;
+ uint32_t remaining_count;
+};
+
+static bool
+tiffer_next_value(struct tiffer_entry *entry)
+{
+ if (!entry->remaining_count)
+ return false;
+
+ entry->p += tiffer_value_size(entry->type);
+ entry->remaining_count--;
+ return true;
+}
+
+static bool
+tiffer_integer(
+ const struct tiffer *self, const struct tiffer_entry *entry, int64_t *out)
+{
+ if (!entry->remaining_count)
+ return false;
+
+ // Somewhat excessively lenient, intended for display.
+ // TIFF 6.0 only directly suggests that a reader is should accept
+ // any of BYTE/SHORT/LONG for unsigned integers.
+ switch (entry->type) {
+ case BYTE:
+ case ASCII:
+ case UNDEFINED:
+ *out = *entry->p;
+ return true;
+ case SBYTE:
+ *out = (int8_t) *entry->p;
+ return true;
+ case SHORT:
+ *out = self->un->u16(entry->p);
+ return true;
+ case SSHORT:
+ *out = (int16_t) self->un->u16(entry->p);
+ return true;
+ case LONG:
+ case IFD:
+ *out = self->un->u32(entry->p);
+ return true;
+ case SLONG:
+ *out = (int32_t) self->un->u32(entry->p);
+ return true;
+ default:
+ return false;
+ }
+}
+
+static bool
+tiffer_rational(const struct tiffer *self, const struct tiffer_entry *entry,
+ int64_t *numerator, int64_t *denominator)
+{
+ if (!entry->remaining_count)
+ return false;
+
+ // Somewhat excessively lenient, intended for display.
+ switch (entry->type) {
+ case RATIONAL:
+ *numerator = self->un->u32(entry->p);
+ *denominator = self->un->u32(entry->p + 4);
+ return true;
+ case SRATIONAL:
+ *numerator = (int32_t) self->un->u32(entry->p);
+ *denominator = (int32_t) self->un->u32(entry->p + 4);
+ return true;
+ default:
+ if (tiffer_integer(self, entry, numerator)) {
+ *denominator = 1;
+ return true;
+ }
+ return false;
+ }
+}
+
+static bool
+tiffer_real(
+ const struct tiffer *self, const struct tiffer_entry *entry, double *out)
+{
+ if (!entry->remaining_count)
+ return false;
+
+ // Somewhat excessively lenient, intended for display.
+ // Assuming the host architecture uses IEEE 754.
+ switch (entry->type) {
+ int64_t numerator, denominator;
+ case FLOAT:
+ *out = *(float *) entry->p;
+ return true;
+ case DOUBLE:
+ *out = *(double *) entry->p;
+ return true;
+ default:
+ if (tiffer_rational(self, entry, &numerator, &denominator)) {
+ *out = (double) numerator / denominator;
+ return true;
+ }
+ return false;
+ }
+}
+
+static bool
+tiffer_next_entry(struct tiffer *self, struct tiffer_entry *entry)
+{
+ if (!self->remaining_fields)
+ return false;
+
+ uint16_t type = entry->type = 0xFFFF;
+ if (!tiffer_u16(self, &entry->tag) || !tiffer_u16(self, &type) ||
+ !tiffer_u32(self, &entry->remaining_count))
+ return false;
+
+ // Short values may and will be inlined, rather than pointed to.
+ size_t values_size = tiffer_value_size(type) * entry->remaining_count;
+ uint32_t offset = 0;
+ if (values_size <= sizeof offset) {
+ entry->p = self->p;
+ self->p += sizeof offset;
+ } else if (tiffer_u32(self, &offset)) {
+ entry->p = self->begin + offset;
+ } else {
+ return false;
+ }
+
+ // All entries are pre-checked not to overflow.
+ if (entry->p + values_size > self->end)
+ return false;
+
+ // Setting it at the end may provide an indication while debugging.
+ entry->type = type;
+ self->remaining_fields--;
+ return true;
+}
+
+// --- TIFF/Exif tags ----------------------------------------------------------
+
+struct tiff_value {
+ const char *name;
+ uint16_t value;
+};
+
+struct tiff_entry {
+ const char *name;
+ uint16_t tag;
+ struct tiff_value *values;
+};
+
+static struct tiff_entry tiff_entries[] = {
+ {"NewSubfileType", 254, NULL},
+ {"SubfileType", 255, (struct tiff_value[]) {
+ {"Full-resolution image data", 1},
+ {"Reduced-resolution image data", 2},
+ {"Page of a multi-page image", 3},
+ {}
+ }},
+ {"ImageWidth", 256, NULL},
+ {"ImageLength", 257, NULL},
+ {"BitsPerSample", 258, NULL},
+ {"Compression", 259, (struct tiff_value[]) {
+ {"Uncompressed", 1},
+ {"CCITT 1D", 2},
+ {"Group 3 Fax", 3},
+ {"Group 4 Fax", 4},
+ {"LZW", 5},
+ {"JPEG", 6},
+ {"JPEG datastream", 7}, // DRAFT TIFF Technical Note 2 + TIFFphotoshop
+ {"Deflate/zlib", 8}, // Adobe Photoshop TIFF Technical Notes
+ {"PackBits", 32773},
+ {"Deflate/zlib", 32946}, // Adobe Photoshop TIFF Technical Notes
+ {}
+ }},
+ {"PhotometricInterpretation", 262, (struct tiff_value[]) {
+ {"WhiteIsZero", 0},
+ {"BlackIsZero", 1},
+ {"RGB", 2},
+ {"RGB Palette", 3},
+ {"Transparency mask", 4},
+ {"CMYK", 5},
+ {"YCbCr", 6},
+ {"CIELab", 8},
+ {"ICCLab", 9}, // Adobe PageMaker 6.0 TIFF Technical Notes
+ {}
+ }},
+ {"Threshholding", 263, (struct tiff_value[]) {
+ {"No dithering or halftoning", 1},
+ {"Ordered dither or halftoning", 2},
+ {"Randomized process", 3},
+ {}
+ }},
+ {"CellWidth", 264, NULL},
+ {"CellLength", 265, NULL},
+ {"FillOrder", 266, (struct tiff_value[]) {
+ {"MSB-first", 1},
+ {"LSB-first", 2},
+ {}
+ }},
+ {"DocumentName", 269, NULL},
+ {"ImageDescription", 270, NULL},
+ {"Make", 271, NULL},
+ {"Model", 272, NULL},
+ {"StripOffsets", 273, NULL},
+ {"Orientation", 274, (struct tiff_value[]) {
+ {"TopLeft", 1},
+ {"TopRight", 2},
+ {"BottomRight", 3},
+ {"BottomLeft", 4},
+ {"LeftTop", 5},
+ {"RightTop", 6},
+ {"RightBottom", 7},
+ {"LeftBottom", 8},
+ {}
+ }},
+ {"SamplesPerPixel", 277, NULL},
+ {"RowsPerStrip", 278, NULL},
+ {"StripByteCounts", 279, NULL},
+ {"MinSampleValue", 280, NULL},
+ {"MaxSampleValue", 281, NULL},
+ {"XResolution", 282, NULL},
+ {"YResolution", 283, NULL},
+ {"PlanarConfiguration", 284, (struct tiff_value[]) {
+ {"Chunky", 1},
+ {"Planar", 2},
+ {}
+ }},
+ {"PageName", 285, NULL},
+ {"XPosition", 286, NULL},
+ {"YPosition", 287, NULL},
+ {"FreeOffsets", 288, NULL},
+ {"FreeByteCounts", 289, NULL},
+ {"GrayResponseUnit", 290, (struct tiff_value[]) {
+ {"1/10", 1},
+ {"1/100", 2},
+ {"1/1000", 3},
+ {"1/10000", 4},
+ {"1/100000", 5},
+ {}
+ }},
+ {"GrayResponseCurve", 291, NULL},
+ {"T4Options", 292, NULL},
+ {"T6Options", 293, NULL},
+ {"ResolutionUnit", 296, (struct tiff_value[]) {
+ {"None", 1},
+ {"Inch", 2},
+ {"Centimeter", 3},
+ {}
+ }},
+ {"PageNumber", 297, NULL},
+ {"TransferFunction", 301, NULL},
+ {"Software", 305, NULL},
+ {"DateTime", 306, NULL},
+ {"Artist", 315, NULL},
+ {"HostComputer", 316, NULL},
+ {"Predictor", 317, (struct tiff_value[]) {
+ {"None", 1},
+ {"Horizontal", 2},
+ {"Floating point", 3}, // Adobe Photoshop TIFF Technical Note 3
+ {}
+ }},
+ {"WhitePoint", 318, NULL},
+ {"PrimaryChromaticities", 319, NULL},
+ {"ColorMap", 320, NULL},
+ {"HalftoneHints", 321, NULL},
+ {"TileWidth", 322, NULL},
+ {"TileLength", 323, NULL},
+ {"TileOffsets", 324, NULL},
+ {"TileByteCounts", 325, NULL},
+ {"SubIFDs", 330, NULL}, // TIFF Technical Note 1: TIFF Trees
+ {"InkSet", 332, (struct tiff_value[]) {
+ {"CMYK", 1},
+ {"Non-CMYK", 2},
+ {}
+ }},
+ {"InkNames", 333, NULL},
+ {"NumberOfInks", 334, NULL},
+ {"DotRange", 336, NULL},
+ {"TargetPrinter", 337, NULL},
+ {"ExtraSamples", 338, (struct tiff_value[]) {
+ {"Unspecified", 0},
+ {"Associated alpha", 1},
+ {"Unassociated alpha", 2},
+ {}
+ }},
+ {"SampleFormat", 339, (struct tiff_value[]) {
+ {"Unsigned integer", 1},
+ {"Two's complement signed integer", 2},
+ {"IEEE floating-point", 3},
+ {"Undefined", 4},
+ {}
+ }},
+ {"SMinSampleValue", 340, NULL},
+ {"SMaxSampleValue", 341, NULL},
+ {"TransferRange", 342, NULL},
+ {"ClipPath", 343, NULL}, // TIFF Technical Note 2: Clipping Path
+ {"XClipPathUnits", 344, NULL}, // TIFF Technical Note 2: Clipping Path
+ {"YClipPathUnits", 345, NULL}, // TIFF Technical Note 2: Clipping Path
+ {"Indexed", 346, NULL}, // TIFF Technical Note 3: Indexed Images
+ {"JPEGTables", 347, NULL}, // DRAFT TIFF Technical Note 2 + TIFFphotoshop
+ {"OPIProxy", 351, NULL}, // Adobe PageMaker 6.0 TIFF Technical Notes
+ {"JPEGProc", 512, (struct tiff_value[]) {
+ {"Baseline sequential", 1},
+ {"Lossless Huffman", 14},
+ {}
+ }},
+ {"JPEGInterchangeFormat", 513, NULL},
+ {"JPEGInterchangeFormatLength", 514, NULL},
+ {"JPEGRestartInterval", 515, NULL},
+ {"JPEGLosslessPredictors", 517, (struct tiff_value[]) {
+ {"A", 1},
+ {"B", 2},
+ {"C", 3},
+ {"A+B+C", 4},
+ {"A+((B-C)/2)", 5},
+ {"B+((A-C)/2)", 6},
+ {"(A+B)/2", 7},
+ {}
+ }},
+ {"JPEGPointTransforms", 518, NULL},
+ {"JPEGQTables", 519, NULL},
+ {"JPEGDCTables", 520, NULL},
+ {"JPEGACTables", 521, NULL},
+ {"YCbCrCoefficients", 529, NULL},
+ {"YCbCrSubSampling", 530, NULL},
+ {"YCbCrPositioning", 531, (struct tiff_value[]) {
+ {"Centered", 1},
+ {"Co-sited", 2},
+ {}
+ }},
+ {"ReferenceBlackWhite", 532, NULL},
+ {"ImageID", 32781, NULL}, // Adobe PageMaker 6.0 TIFF Technical Notes
+ {"Copyright", 33432, NULL},
+ // TODO(p): Extract PSIRs, like we do directly with the JPEG segment.
+ {"Photoshop", 34377, NULL}, // Adobe XMP Specification Part 3 Table 12/39
+ {"Exif IFD Pointer", 34665, NULL}, // Exif 2.3
+ {"GPS Info IFD Pointer", 34853, NULL}, // Exif 2.3
+ // TODO(p): Extract IPTC DataSets, like we do directly with PSIRs.
+ {"IPTC", 37723, NULL}, // Adobe XMP Specification Part 3 Table 12/39
+ {"ImageSourceData", 37724, NULL}, // Adobe Photoshop TIFF Technical Notes
+ {}
+};
+
+// Exif 2.3 4.6.5
+static struct tiff_entry exif_entries[] = {
+ {"ExposureTime", 33434, NULL},
+ {"FNumber", 33437, NULL},
+ {"ExposureProgram", 34850, (struct tiff_value[]) {
+ {"Not defined", 0},
+ {"Manual", 1},
+ {"Normal program", 2},
+ {"Aperture priority", 3},
+ {"Shutter priority", 4},
+ {"Creative program", 5},
+ {"Action program", 6},
+ {"Portrait mode", 7},
+ {"Landscape mode", 8},
+ {}
+ }},
+ {"SpectralSensitivity", 34852, NULL},
+ {"PhotographicSensitivity", 34855, NULL},
+ {"OECF", 34856, NULL},
+ {"SensitivityType", 34864, (struct tiff_value[]) {
+ {"Unknown", 0},
+ {"Standard output sensitivity", 1},
+ {"Recommended exposure index", 2},
+ {"ISO speed", 3},
+ {"SOS and REI", 4},
+ {"SOS and ISO speed", 5},
+ {"REI and ISO speed", 6},
+ {"SOS and REI and ISO speed", 7},
+ {}
+ }},
+ {"StandardOutputSensitivity", 34865, NULL},
+ {"RecommendedExposureIndex", 34866, NULL},
+ {"ISOSpeed", 34867, NULL},
+ {"ISOSpeedLatitudeyyy", 34868, NULL},
+ {"ISOSpeedLatitudezzz", 34869, NULL},
+ {"ExifVersion", 36864, NULL},
+ {"DateTimeOriginal", 36867, NULL},
+ {"DateTimeDigitized", 36868, NULL},
+ {"OffsetTime", 36880, NULL}, // 2.31
+ {"OffsetTimeOriginal", 36881, NULL}, // 2.31
+ {"OffsetTimeDigitized", 36882, NULL}, // 2.31
+ {"ComponentsConfiguration", 37121, (struct tiff_value[]) {
+ {"Does not exist", 0},
+ {"Y", 1},
+ {"Cb", 2},
+ {"Cr", 3},
+ {"R", 4},
+ {"G", 5},
+ {"B", 6},
+ {}
+ }},
+ {"CompressedBitsPerPixel", 37122, NULL},
+ {"ShutterSpeedValue", 37377, NULL},
+ {"ApertureValue", 37378, NULL},
+ {"BrightnessValue", 37379, NULL},
+ {"ExposureBiasValue", 37380, NULL},
+ {"MaxApertureValue", 37381, NULL},
+ {"SubjectDistance", 37382, NULL},
+ {"MeteringMode", 37383, (struct tiff_value[]) {
+ {"Unknown", 0},
+ {"Average", 1},
+ {"CenterWeightedAverage", 2},
+ {"Spot", 3},
+ {"MultiSpot", 4},
+ {"Pattern", 5},
+ {"Partial", 6},
+ {"Other", 255},
+ {}
+ }},
+ {"LightSource", 37384, (struct tiff_value[]) {
+ {"Unknown", 0},
+ {"Daylight", 1},
+ {"Fluorescent", 2},
+ {"Tungsten (incandescent light)", 3},
+ {"Flash", 4},
+ {"Fine weather", 9},
+ {"Cloudy weather", 10},
+ {"Shade", 11},
+ {"Daylight fluorescent (D 5700 - 7100K)", 12},
+ {"Day white fluorescent (N 4600 - 5500K)", 13},
+ {"Cool white fluorescent (W 3800 - 4500K)", 14},
+ {"White fluorescent (WW 3250 - 3800K)", 15},
+ {"Warm white fluorescent (L 2600 - 3250K)", 16},
+ {"Standard light A", 17},
+ {"Standard light B", 18},
+ {"Standard light C", 19},
+ {"D55", 20},
+ {"D65", 21},
+ {"D75", 22},
+ {"D50", 23},
+ {"ISO studio tungsten", 24},
+ {"Other light source", 255},
+ {}
+ }},
+ {"Flash", 37385, NULL},
+ {"FocalLength", 37386, NULL},
+ {"SubjectArea", 37396, NULL},
+ {"MakerNote", 37500, NULL},
+ // TODO(p): Decode.
+ {"UserComment", 37510, NULL},
+ {"SubSecTime", 37520, NULL},
+ {"SubSecTimeOriginal", 37521, NULL},
+ {"SubSecTimeDigitized", 37522, NULL},
+ {"Temperature", 37888, NULL}, // 2.31
+ {"Humidity", 37889, NULL}, // 2.31
+ {"Pressure", 37890, NULL}, // 2.31
+ {"WaterDepth", 37891, NULL}, // 2.31
+ {"Acceleration", 37892, NULL}, // 2.31
+ {"CameraElevationAngle", 37893, NULL}, // 2.31
+ {"FlashpixVersion", 40960, NULL},
+ {"ColorSpace", 40961, (struct tiff_value[]) {
+ {"sRGB", 1},
+ {"Uncalibrated", 0xFFFF},
+ {}
+ }},
+ {"PixelXDimension", 40962, NULL},
+ {"PixelYDimension", 40963, NULL},
+ {"RelatedSoundFile", 40964, NULL},
+ {"Interoperability IFD Pointer", 40965, NULL},
+ {"FlashEnergy", 41483, NULL},
+ {"SpatialFrequencyResponse", 41484, NULL},
+ {"FocalPlaneXResolution", 41486, NULL},
+ {"FocalPlaneYResolution", 41487, NULL},
+ {"FocalPlaneResolutionUnit", 41488, NULL},
+ {"SubjectLocation", 41492, NULL},
+ {"ExposureIndex", 41493, NULL},
+ {"SensingMethod", 41495, (struct tiff_value[]) {
+ {"Not defined", 1},
+ {"One-chip color area sensor", 2},
+ {"Two-chip color area sensor", 3},
+ {"Three-chip color area sensor", 4},
+ {"Color sequential area sensor", 5},
+ {"Trilinear sensor", 7},
+ {"Color sequential linear sensor", 8},
+ {}
+ }},
+ {"FileSource", 41728, (struct tiff_value[]) {
+ {"Others", 0},
+ {"Scanner of transparent type", 1},
+ {"Scanner of reflex type", 2},
+ {"DSC", 3},
+ {}
+ }},
+ {"SceneType", 41729, (struct tiff_value[]) {
+ {"Directly-photographed image", 1},
+ {}
+ }},
+ {"CFAPattern", 41730, NULL},
+ {"CustomRendered", 41985, (struct tiff_value[]) {
+ {"Normal process", 0},
+ {"Custom process", 1},
+ {}
+ }},
+ {"ExposureMode", 41986, (struct tiff_value[]) {
+ {"Auto exposure", 0},
+ {"Manual exposure", 1},
+ {"Auto bracket", 2},
+ {}
+ }},
+ {"WhiteBalance", 41987, (struct tiff_value[]) {
+ {"Auto white balance", 0},
+ {"Manual white balance", 1},
+ {}
+ }},
+ {"DigitalZoomRatio", 41988, NULL},
+ {"FocalLengthIn35mmFilm", 41989, NULL},
+ {"SceneCaptureType", 41990, (struct tiff_value[]) {
+ {"Standard", 0},
+ {"Landscape", 1},
+ {"Portrait", 2},
+ {"Night scene", 3},
+ {}
+ }},
+ {"GainControl", 41991, (struct tiff_value[]) {
+ {"None", 0},
+ {"Low gain up", 1},
+ {"High gain up", 2},
+ {"Low gain down", 3},
+ {"High gain down", 4},
+ {}
+ }},
+ {"Contrast", 41992, (struct tiff_value[]) {
+ {"Normal", 0},
+ {"Soft", 1},
+ {"Hard", 2},
+ {}
+ }},
+ {"Saturation", 41993, (struct tiff_value[]) {
+ {"Normal", 0},
+ {"Low", 1},
+ {"High", 2},
+ {}
+ }},
+ {"Sharpness", 41994, (struct tiff_value[]) {
+ {"Normal", 0},
+ {"Soft", 1},
+ {"Hard", 2},
+ {}
+ }},
+ {"DeviceSettingDescription", 41995, NULL},
+ {"SubjectDistanceRange", 41996, (struct tiff_value[]) {
+ {"Unknown", 0},
+ {"Macro", 1},
+ {"Close view", 2},
+ {"Distant view", 3},
+ {}
+ }},
+ {"ImageUniqueID", 42016, NULL},
+ {"CameraOwnerName", 42032, NULL},
+ {"BodySerialNumber", 42033, NULL},
+ {"LensSpecification", 42034, NULL},
+ {"LensMake", 42035, NULL},
+ {"LensModel", 42036, NULL},
+ {"LensSerialNumber", 42037, NULL},
+ {"CompositeImage", 42080, NULL}, // 2.32
+ {"SourceImageNumberOfCompositeImage", 42081, NULL}, // 2.32
+ {"SourceExposureTimesOfCompositeImage", 42082, NULL}, // 2.32
+ {"Gamma", 42240, NULL},
+ {}
+};
+
+// Exif 2.3 4.6.6 (Notice it starts at 0.)
+static struct tiff_entry exif_gps_entries[] = {
+ {"GPSVersionID", 0, NULL},
+ {"GPSLatitudeRef", 1, NULL},
+ {"GPSLatitude", 2, NULL},
+ {"GPSLongitudeRef", 3, NULL},
+ {"GPSLongitude", 4, NULL},
+ {"GPSAltitudeRef", 5, (struct tiff_value[]) {
+ {"Sea level", 0},
+ {"Sea level reference (negative value)", 1},
+ {}
+ }},
+ {"GPSAltitude", 6, NULL},
+ {"GPSTimeStamp", 7, NULL},
+ {"GPSSatellites", 8, NULL},
+ {"GPSStatus", 9, NULL},
+ {"GPSMeasureMode", 10, NULL},
+ {"GPSDOP", 11, NULL},
+ {"GPSSpeedRef", 12, NULL},
+ {"GPSSpeed", 13, NULL},
+ {"GPSTrackRef", 14, NULL},
+ {"GPSTrack", 15, NULL},
+ {"GPSImgDirectionRef", 16, NULL},
+ {"GPSImgDirection", 17, NULL},
+ {"GPSMapDatum", 18, NULL},
+ {"GPSDestLatitudeRef", 19, NULL},
+ {"GPSDestLatitude", 20, NULL},
+ {"GPSDestLongitudeRef", 21, NULL},
+ {"GPSDestLongitude", 22, NULL},
+ {"GPSDestBearingRef", 23, NULL},
+ {"GPSDestBearing", 24, NULL},
+ {"GPSDestDistanceRef", 25, NULL},
+ {"GPSDestDistance", 26, NULL},
+ {"GPSProcessingMethod", 27, NULL},
+ {"GPSAreaInformation", 28, NULL},
+ {"GPSDateStamp", 29, NULL},
+ {"GPSDifferential", 30, (struct tiff_value[]) {
+ {"Measurement without differential correction", 0},
+ {"Differential correction applied", 1},
+ {}
+ }},
+ {"GPSHPositioningError", 31, NULL},
+ {}
+};
+
+// Exif 2.3 4.6.7 (Notice it starts at 1, and collides with GPS.)
+static struct tiff_entry exif_interop_entries[] = {
+ {"InteroperabilityIndex", 1, NULL},
+ {}
+};
+
+// TODO(p): Consider if these can't be inlined into `tiff_entries`.
+static struct {
+ uint16_t tag;
+ struct tiff_entry *entries;
+} tiff_subifds[] = {
+ {330, tiff_entries}, // SubIFDs
+ {34665, exif_entries}, // Exif IFD Pointer
+ {34853, exif_gps_entries}, // GPS Info IFD Pointer
+ {40965, exif_interop_entries}, // Interoperability IFD Pointer
+ {}
+};
+
+// --- Analysis ----------------------------------------------------------------
+
+static jv
+add_to_subarray(jv o, const char *key, jv value)
+{
+ // Invalid values are not allocated, and we use up any valid one.
+ // Beware that jv_get() returns jv_null() rather than jv_invalid().
+ // Also, the header comment is lying, jv_is_valid() doesn't unreference.
+ jv a = jv_object_get(jv_copy(o), jv_string(key));
+ return jv_set(o, jv_string(key),
+ jv_is_valid(a) ? jv_array_append(a, value) : JV_ARRAY(value));
+}
+
+static jv
+add_warning(jv o, const char *message)
+{
+ return add_to_subarray(o, "warnings", jv_string(message));
+}
+
+static jv
+add_error(jv o, const char *message)
+{
+ return jv_object_set(o, jv_string("error"), jv_string(message));
+}
+
+// --- Exif --------------------------------------------------------------------
+
+static jv parse_exif_ifd(struct tiffer *T, const struct tiff_entry *info);
+
+static jv
+parse_exif_subifds(struct tiffer *T, const struct tiffer_entry *entry,
+ struct tiff_entry *info)
+{
+ int64_t offset = 0;
+ struct tiffer subT = {};
+ if (!tiffer_integer(T, entry, &offset) ||
+ offset < 0 || offset > UINT32_MAX || !tiffer_subifd(T, offset, &subT))
+ return jv_null();
+
+ // The chain should correspond to the values in the entry,
+ // we are not going to verify it.
+ jv a = jv_array();
+ do a = jv_array_append(a, parse_exif_ifd(&subT, info));
+ while (tiffer_next_ifd(&subT));
+ return a;
+}
+
+static jv
+parse_exif_ascii(struct tiffer_entry *entry)
+{
+ // Adobe XMP Specification Part 3: Storage in Files, 2020/1, 2.4.2
+ // The text may in practice contain any 8-bit encoding, but likely UTF-8.
+ // TODO(p): Validate UTF-8, and assume Latin 1 if unsuccessful.
+ jv a = jv_array();
+ uint8_t *nul = 0;
+ while ((nul = memchr(entry->p, 0, entry->remaining_count))) {
+ size_t len = nul - entry->p;
+ a = jv_array_append(a, jv_string_sized((const char *) entry->p, len));
+ entry->remaining_count -= len + 1;
+ entry->p += len + 1;
+ }
+
+ // Trailing NULs are required, but let's extract everything.
+ if (entry->remaining_count) {
+ a = jv_array_append(a,
+ jv_string_sized((const char *) entry->p, entry->remaining_count));
+ }
+ return a;
+}
+
+static jv
+parse_exif_undefined(struct tiffer_entry *entry)
+{
+ // Sometimes, it can be ASCII, but the safe bet is to hex-encode it.
+ char *buf = binhex(entry->p, entry->remaining_count);
+ jv s = jv_string(buf);
+ free(buf);
+ return s;
+}
+
+static jv
+parse_exif_value(const struct tiff_value *values, double real)
+{
+ if (values) {
+ for (; values->name; values++)
+ if (values->value == real)
+ return jv_string(values->name);
+ }
+ return jv_number(real);
+}
+static jv
+parse_exif_extract_sole_array_element(jv a)
+{
+ return jv_array_length(jv_copy(a)) == 1 ? jv_array_get(a, 0) : a;
+}
+
+static jv
+parse_exif_entry(jv o, struct tiffer *T, struct tiffer_entry *entry,
+ const struct tiff_entry *info)
+{
+ if (!info)
+ info = (struct tiff_entry[]) {{}};
+
+ for (; info->name; info++)
+ if (info->tag == entry->tag)
+ break;
+
+ struct tiff_entry *subentries = NULL;
+ for (size_t i = 0; tiff_subifds[i].tag; i++)
+ if (tiff_subifds[i].tag == entry->tag)
+ subentries = tiff_subifds[i].entries;
+
+ jv v = jv_true();
+ double real = 0;
+ if (!entry->remaining_count) {
+ v = jv_null();
+ } else if (entry->type == IFD || subentries) {
+ v = parse_exif_subifds(T, entry, subentries);
+ } else if (entry->type == ASCII) {
+ v = parse_exif_extract_sole_array_element(parse_exif_ascii(entry));
+ } else if (entry->type == UNDEFINED && !info->values) {
+ // Several Exif entries of UNDEFINED type contain single-byte numbers.
+ v = parse_exif_undefined(entry);
+ } else if (tiffer_real(T, entry, &real)) {
+ v = jv_array();
+ do v = jv_array_append(v, parse_exif_value(info->values, real));
+ while (tiffer_next_value(entry) && tiffer_real(T, entry, &real));
+ v = parse_exif_extract_sole_array_element(v);
+ }
+
+ if (info->name)
+ return jv_set(o, jv_string(info->name), v);
+ return jv_set(o, jv_string_fmt("%u", entry->tag), v);
+}
+
+static jv
+parse_exif_ifd(struct tiffer *T, const struct tiff_entry *info)
+{
+ jv ifd = jv_object();
+ struct tiffer_entry entry = {};
+ while (tiffer_next_entry(T, &entry))
+ ifd = parse_exif_entry(ifd, T, &entry, info);
+ return ifd;
+}
+
+static jv
+parse_exif(jv o, const uint8_t *p, size_t len)
+{
+ struct tiffer T = {};
+ if (!tiffer_init(&T, p, len))
+ return add_warning(o, "invalid Exif");
+ while (tiffer_next_ifd(&T))
+ o = add_to_subarray(o, "Exif", parse_exif_ifd(&T, tiff_entries));
+ return o;
+}
+
+// --- Photoshop Image Resources -----------------------------------------------
+// Adobe XMP Specification Part 3: Storage in Files, 2020/1, 1.1.3 + 3.1.3
+// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/
+// Unless otherwise noted, the descriptions are derived from the above document.
+
+static struct {
+ uint16_t id;
+ const char *description;
+} psir_descriptions[] = {
+ {1000, "Number of channels, rows, columns, depth, mode"},
+ {1001, "Macintosh print manager print info record"},
+ {1002, "Macintosh page format information"},
+ {1003, "Indexed color table"},
+ {1005, "Resolution information"},
+ {1006, "Names of alpha channels (Pascal strings)"},
+ {1007, "Display information"},
+ {1008, "Caption (Pascal string)"}, // XMP Part 3 3.3.3
+ {1009, "Border information"},
+ {1010, "Background color"},
+ {1011, "Print flags"},
+ {1012, "Grayscale and multichannel halftoning information"},
+ {1013, "Color halftoning information"},
+ {1014, "Duotone halftoning information"},
+ {1015, "Grayscale and multichannel transfer function"},
+ {1016, "Color transfer functions"},
+ {1017, "Duotone transfer functions"},
+ {1018, "Duotone image information"},
+ {1019, "Effective B/W values for the dot range"},
+ {1020, "Caption"}, // XMP Part 3 3.3.3
+ {1021, "EPS options"},
+ {1022, "Quick Mask information"},
+ {1023, "(Obsolete)"},
+ {1024, "Layer state information"},
+ {1025, "Working path (not saved)"},
+ {1026, "Layers group information"},
+ {1027, "(Obsolete)"},
+ {1028, "IPTC DataSets"}, // XMP Part 3 3.3.3
+ {1029, "Image mode for raw format files"},
+ {1030, "JPEG quality"},
+ {1032, "Grid and guides information"},
+ {1033, "Thumbnail resource"},
+ {1034, "Copyright flag"},
+ {1035, "Copyright information URL"}, // XMP Part 3 3.3.3
+ {1036, "Thumbnail resource"},
+ {1037, "Global lighting angle for effects layer"},
+ {1038, "Color samplers information"},
+ {1039, "ICC profile"},
+ {1040, "Watermark"},
+ {1041, "ICC untagged profile flag"},
+ {1042, "Effects visible flag"},
+ {1043, "Spot halftone"},
+ {1044, "Document-specific IDs seed number"},
+ {1045, "Unicode alpha names"},
+ {1046, "Indexed color table count"},
+ {1047, "Transparent color index"},
+ {1049, "Global altitude"},
+ {1050, "Slices"},
+ {1051, "Workflow URL"},
+ {1052, "Jump To XPEP"},
+ {1053, "Alpha identifiers"},
+ {1054, "URL list"},
+ {1057, "Version info"},
+ {1058, "Exif metadata 1"},
+ {1059, "Exif metadata 3"},
+ {1060, "XMP metadata"},
+ {1061, "MD5 digest of IPTC data"}, // XMP Part 3 3.3.3
+ {1062, "Print scale"},
+ {1064, "Pixel aspect ratio"},
+ {1065, "Layer comps"},
+ {1066, "Alternate duotone colors"},
+ {1067, "Alternate spot colors"},
+ {1069, "Layer selection IDs"},
+ {1070, "HDR toning information"},
+ {1071, "Print info"},
+ {1072, "Layer group(s) enabled ID"},
+ {1073, "Color samplers"},
+ {1074, "Measurement scale"},
+ {1075, "Timeline information"},
+ {1076, "Sheet disclosure"},
+ {1077, "Display information to support floating point colors"},
+ {1078, "Onion skins"},
+ {1080, "Count information"},
+ {1082, "Print information"},
+ {1083, "Print style"},
+ {1084, "Macintosh NSPrintInfo"},
+ {1085, "Windows DEVMODE"},
+ {1086, "Autosave file path"},
+ {1087, "Autosave format"},
+ {1088, "Path selection state"},
+ // {2000-2997, "Saved paths"},
+ {2999, "Name of clipping path"},
+ {3000, "Origin path information"},
+ // {4000-4999, "Plug-in resource"},
+ {7000, "Image Ready variables"},
+ {7001, "Image Ready data sets"},
+ {7002, "Image Ready default selected state"},
+ {7003, "Image Ready 7 rollover expanded state"},
+ {7004, "Image Ready rollover expanded state"},
+ {7005, "Image Ready save layer settings"},
+ {7006, "Image Ready version"},
+ {8000, "Lightroom workflow"},
+ {10000, "Print flags"},
+ {}
+};
+
+static jv
+process_psir_thumbnail(jv res, const uint8_t *data, size_t len)
+{
+ uint32_t format_number = u32be(data + 0);
+ uint32_t compressed_size = u32be(data + 20);
+
+ // TODO(p): Recurse into the thumbnail if it's a JPEG.
+ jv format = jv_number(format_number);
+ switch (format_number) {
+ break; case 0: format = jv_string("kJpegRGB");
+ break; case 1: format = jv_string("kRawRGB");
+ }
+
+ res = jv_object_merge(res, JV_OBJECT(
+ jv_string("Format"), format,
+ jv_string("Width"), jv_number(u32be(data + 4)),
+ jv_string("Height"), jv_number(u32be(data + 8)),
+ jv_string("Stride"), jv_number(u32be(data + 12)),
+ jv_string("TotalSize"), jv_number(u32be(data + 16)),
+ jv_string("CompressedSize"), jv_number(compressed_size),
+ jv_string("BitsPerPixel"), jv_number(u16be(data + 24)),
+ jv_string("Planes"), jv_number(u16be(data + 26))
+ ));
+ if (28 + compressed_size <= len) {
+ char *buf = binhex(data + 28, compressed_size);
+ res = jv_set(res, jv_string("Data"), jv_string(buf));
+ free(buf);
+ }
+ return res;
+}
+
+static const char *
+process_iptc_dataset(jv *a, const uint8_t **p, size_t len)
+{
+ const uint8_t *header = *p;
+ if (len < 5)
+ return "unexpected end of IPTC data";
+ if (*header != 0x1c)
+ return "invalid tag marker";
+
+ uint8_t record = header[1];
+ uint8_t dataset = header[2];
+ uint16_t byte_count = header[3] << 8 | header[4];
+
+ // TODO(p): Although highly unlikely to appear, we could decode it.
+ if (byte_count & 0x8000)
+ return "unsupported extended DataSet";
+ if (len - 5 < byte_count)
+ return "data overrun";
+
+ char *buf = binhex(header + 5, byte_count);
+ *p += 5 + byte_count;
+ *a = jv_array_append(*a, JV_OBJECT(
+ jv_string("DataSet"), jv_string_fmt("%u:%u", record, dataset),
+ jv_string("Data"), jv_string(buf)
+ ));
+ free(buf);
+ return NULL;
+}
+
+static jv
+process_psir_iptc(jv res, const uint8_t *data, size_t len)
+{
+ // https://iptc.org/standards/iim/
+ // https://iptc.org/std/IIM/4.2/specification/IIMV4.2.pdf
+ jv a = jv_array();
+ const uint8_t *end = data + len;
+ while (data < end) {
+ const char *err = process_iptc_dataset(&a, &data, end - data);
+ if (err) {
+ a = jv_array_append(a, jv_string(err));
+ break;
+ }
+ }
+ return jv_set(res, jv_string("DataSets"), a);
+}
+
+static jv
+process_psir(jv o, uint16_t resource_id, const char *name,
+ const uint8_t *data, size_t len)
+{
+ const char *description = NULL;
+ if (resource_id >= 2000 && resource_id <= 2997)
+ description = "Saved paths";
+ if (resource_id >= 4000 && resource_id <= 4999)
+ description = "Plug-in resource";
+ for (size_t i = 0; psir_descriptions[i].id; i++)
+ if (psir_descriptions[i].id == resource_id)
+ description = psir_descriptions[i].description;
+
+ jv res = JV_OBJECT(
+ jv_string("name"), jv_string(name),
+ jv_string("id"), jv_number(resource_id),
+ jv_string("description"),
+ description ? jv_string(description) : jv_null(),
+ jv_string("size"), jv_number(len)
+ );
+
+ // Both are thumbnails, older is BGR, newer is RGB.
+ if ((resource_id == 1033 || resource_id == 1036) && len >= 28)
+ res = process_psir_thumbnail(res, data, len);
+ if (resource_id == 1028)
+ res = process_psir_iptc(res, data, len);
+
+ return add_to_subarray(o, "PSIR", res);
+}
+
+static jv
+parse_psir_block(jv o, const uint8_t *p, size_t len, size_t *advance)
+{
+ *advance = 0;
+ if (len < 8 || memcmp(p, "8BIM", 4))
+ return add_warning(o, "bad PSIR block header");
+
+ uint16_t resource_id = u16be(p + 4);
+ uint8_t name_len = p[6];
+ const uint8_t *name = &p[7];
+
+ // Add one byte for the Pascal-ish string length prefix,
+ // then another one for padding to make the length even.
+ size_t name_len_full = (name_len + 2) & ~1U;
+
+ size_t resource_len_offset = 6 + name_len_full,
+ header_len = resource_len_offset + 4;
+ if (len < header_len)
+ return add_warning(o, "bad PSIR block header");
+
+ uint32_t resource_len = u32be(p + resource_len_offset);
+ size_t resource_len_padded = (resource_len + 1) & ~1U;
+ if (resource_len_padded < resource_len ||
+ len < header_len + resource_len_padded)
+ return add_warning(o, "runaway PSIR block");
+
+ char *cname = calloc(1, name_len_full);
+ strncpy(cname, (const char *) name, name_len);
+ o = process_psir(o, resource_id, cname, p + header_len, resource_len);
+ free(cname);
+
+ *advance = header_len + resource_len_padded;
+ return o;
+}
+
+static jv
+parse_psir(jv o, const uint8_t *p, size_t len)
+{
+ if (len == 0)
+ return add_warning(o, "empty PSIR data");
+
+ size_t advance = 0;
+ while (len && (o = parse_psir_block(o, p, len, &advance), advance)) {
+ p += advance;
+ len -= advance;
+ }
+ return o;
+}