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fiv/tools/info.h

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//
// info.h: metadata extraction utilities
//
// Copyright (c) 2021 - 2023, 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 <stdbool.h>
#include <stdlib.h>
#include <string.h>
// --- TIFF/Exif ---------------------------------------------------------------
#include "tiff-tables.h"
#include "tiffer.h"
// 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_interoperability_entries}, // Interoperability IFD Pointer
{}
};
// --- Utilities ---------------------------------------------------------------
#define u64be tiffer_u64be
#define u32be tiffer_u32be
#define u16be tiffer_u16be
#define u64le tiffer_u64le
#define u32le tiffer_u32le
#define u16le tiffer_u16le
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;
}
// --- 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));
}
// Forward declaration.
static jv parse_jpeg(jv o, const uint8_t *p, size_t len);
// --- Exif --------------------------------------------------------------------
static jv parse_exif_ifd(struct tiffer *T, const struct tiff_entry *info);
static bool
parse_exif_subifds_entry(const struct tiffer *T,
const struct tiffer_entry *entry, struct tiffer *subT)
{
int64_t offset = 0;
return tiffer_integer(T, entry, &offset) &&
offset >= 0 && offset <= UINT32_MAX && tiffer_subifd(T, offset, subT);
}
static jv
parse_exif_subifds(const struct tiffer *T, struct tiffer_entry *entry,
struct tiff_entry *info)
{
struct tiffer subT = {};
if (!parse_exif_subifds_entry(T, entry, &subT))
return jv_null();
jv a = jv_array();
do a = jv_array_append(a, parse_exif_ifd(&subT, info));
while (tiffer_next_ifd(&subT));
// The chain should correspond to the values in the entry (see TIFF
// Technical Note 1: "the NextIFD value of Child #1 must point to Child #2,
// and so on"), but at least some Nikon NEFs do not follow this rule.
if (jv_array_length(jv_copy(a)) == 1) {
while (tiffer_next_value(entry) &&
parse_exif_subifds_entry(T, entry, &subT))
a = jv_array_append(a, parse_exif_ifd(&subT, info));
}
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, const struct tiffer *T, struct tiffer_entry *entry,
const struct tiff_entry *info)
{
static struct tiff_entry empty[] = {{}};
if (!info)
info = empty;
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)
{
int64_t compression = 0,
jpeg = 0, jpeg_length = 0, strip_offsets = 0, strip_byte_counts = 0;
jv ifd = jv_object();
struct tiffer_entry entry = {};
while (tiffer_next_entry(T, &entry)) {
switch (entry.tag) {
case TIFF_Compression:
tiffer_integer(T, &entry, &compression);
break;
case TIFF_JPEGInterchangeFormat:
tiffer_integer(T, &entry, &jpeg);
break;
case TIFF_JPEGInterchangeFormatLength:
tiffer_integer(T, &entry, &jpeg_length);
break;
case TIFF_StripOffsets:
tiffer_integer(T, &entry, &strip_offsets);
break;
case TIFF_StripByteCounts:
tiffer_integer(T, &entry, &strip_byte_counts);
break;
}
ifd = parse_exif_entry(ifd, T, &entry, info);
}
// This is how Exif specifies it, which doesn't follow TIFF 6.0.
if (info == tiff_entries && compression == TIFF_Compression_JPEG &&
jpeg > 0 && jpeg_length > 0 &&
jpeg + jpeg_length < (T->end - T->begin)) {
ifd = jv_set(ifd, jv_string("JPEG image data"),
parse_jpeg(
jv_object(), T->begin + jpeg, jpeg_length));
}
// Theoretically, there may be more strips, but this is not expected.
if (info == tiff_entries &&
compression == TIFF_Compression_JPEGDatastream &&
strip_offsets > 0 && strip_byte_counts > 0 &&
strip_offsets + strip_byte_counts < (T->end - T->begin)) {
ifd = jv_set(ifd, jv_string("JPEG image data"),
parse_jpeg(
jv_object(), T->begin + strip_offsets, strip_byte_counts));
}
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;
}
// --- ICC profiles ------------------------------------------------------------
// v2 https://www.color.org/ICC_Minor_Revision_for_Web.pdf
// v4 https://www.color.org/specification/ICC1v43_2010-12.pdf
static jv
parse_icc_mluc(jv o, const uint8_t *tag, uint32_t tag_length)
{
// v4 10.13
if (tag_length < 16)
return add_warning(o, "invalid ICC 'mluc' structure length");
uint32_t count = u32be(tag + 8);
if (count == 0)
return add_warning(o, "unnamed ICC profile");
// There is no particularly good reason for us to iterate, take the first.
const uint8_t *record = tag + 16 /* + i * u32be(tag + 12) */;
uint32_t len = u32be(&record[4]);
uint32_t off = u32be(&record[8]);
if (off + len > tag_length)
return add_warning(o, "invalid ICC 'mluc' structure record");
// Blindly assume simple ASCII, ensure NUL-termination.
char name[len], *p = name;
for (uint32_t i = 0; i < len / 2; i++)
*p++ = tag[off + i * 2 + 1];
*p++ = 0;
return jv_set(o, jv_string("ICC"),
JV_OBJECT(jv_string("name"), jv_string(name),
jv_string("version"), jv_number(4)));
}
static jv
parse_icc_desc(jv o, const uint8_t *profile, size_t profile_len,
uint32_t tag_offset, uint32_t tag_length)
{
const uint8_t *tag = profile + tag_offset;
if (tag_offset + tag_length > profile_len)
return add_warning(o, "unexpected end of ICC profile");
if (tag_length < 4)
return add_warning(o, "invalid ICC tag structure length");
// v2 6.5.17
uint32_t sig = u32be(tag);
if (sig == 0x6D6C7563 /* mluc */)
return parse_icc_mluc(o, profile + tag_offset, tag_length);
if (sig != 0x64657363 /* desc */)
return add_warning(o, "invalid ICC 'desc' structure signature");
if (tag_length < 12)
return add_warning(o, "invalid ICC 'desc' structure length");
uint32_t count = u32be(tag + 8);
if (tag_length < 12 + count)
return add_warning(o, "invalid ICC 'desc' structure length");
// Double-ensure a trailing NUL byte.
char name[count + 1];
memcpy(name, tag + 12, count);
name[count] = 0;
return jv_set(o, jv_string("ICC"),
JV_OBJECT(jv_string("name"), jv_string(name),
jv_string("version"), jv_number(2)));
}
static jv
parse_icc(jv o, const uint8_t *profile, size_t profile_len)
{
// v2 6, v4 7
if (profile_len < 132)
return add_warning(o, "ICC profile too short");
if (u32be(profile) != profile_len)
return add_warning(o, "ICC profile size mismatch");
// TODO(p): May decode more of the header fields, and validate them.
// Need to check both v2 and v4, this is all fairly annoying.
uint32_t count = u32be(profile + 128);
if (132 + count * 12 > profile_len)
return add_warning(o, "unexpected end of ICC profile");
for (uint32_t i = 0; i < count; i++) {
const uint8_t *entry = profile + 132 + i * 12;
uint32_t sig = u32be(&entry[0]);
uint32_t off = u32be(&entry[4]);
uint32_t len = u32be(&entry[8]);
// v2 6.4.32, v4 9.2.41
if (sig == 0x64657363 /* desc */)
return parse_icc_desc(o, profile, profile_len, off, len);
}
// The description is required, so this should be unreachable.
return jv_set(o, jv_string("ICC"), jv_bool(true));
}
// --- Multi-Picture Format ----------------------------------------------------
static uint32_t
parse_mpf_mpentry(jv *a, const uint8_t *p, const struct tiffer *T)
{
uint32_t attrs = T->un->u32(p);
uint32_t offset = T->un->u32(p + 8);
uint32_t type_number = attrs & 0xFFFFFF;
jv type = jv_number(type_number);
switch (type_number) {
break; case 0x030000: type = jv_string("Baseline MP Primary Image");
break; case 0x010001: type = jv_string("Large Thumbnail - VGA");
break; case 0x010002: type = jv_string("Large Thumbnail - Full HD");
break; case 0x020001: type = jv_string("Multi-Frame Image Panorama");
break; case 0x020002: type = jv_string("Multi-Frame Image Disparity");
break; case 0x020003: type = jv_string("Multi-Frame Image Multi-Angle");
break; case 0x000000: type = jv_string("Undefined");
}
uint32_t format_number = (attrs >> 24) & 0x7;
jv format = jv_number(format_number);
if (format_number == 0)
format = jv_string("JPEG");
*a = jv_array_append(*a, JV_OBJECT(
jv_string("Individual Image Attribute"), JV_OBJECT(
jv_string("Dependent Parent Image"), jv_bool((attrs >> 31) & 1),
jv_string("Dependent Child Image"), jv_bool((attrs >> 30) & 1),
jv_string("Representative Image"), jv_bool((attrs >> 29) & 1),
jv_string("Reserved"), jv_number((attrs >> 27) & 0x3),
jv_string("Image Data Format"), format,
jv_string("MP Type Code"), type
),
jv_string("Individual Image Size"),
jv_number(T->un->u32(p + 4)),
jv_string("Individual Image Data Offset"),
jv_number(offset),
jv_string("Dependent Image 1 Entry Number"),
jv_number(T->un->u16(p + 12)),
jv_string("Dependent Image 2 Entry Number"),
jv_number(T->un->u16(p + 14))
));
// Don't report non-JPEGs, even though they're unlikely.
return format_number == 0 ? offset : 0;
}
static jv
parse_mpf_index_entry(jv o, uint32_t **offsets, const struct tiffer *T,
struct tiffer_entry *entry)
{
// 5.2.3.3. MP Entry
if (entry->tag != MPF_MPEntry || entry->type != UNDEFINED ||
entry->remaining_count % 16) {
return parse_exif_entry(o, T, entry, mpf_entries);
}
uint32_t count = entry->remaining_count / 16;
jv a = jv_array_sized(count);
uint32_t *out = *offsets = calloc(sizeof *out, count + 1);
for (uint32_t i = 0; i < count; i++) {
// 5.2.3.3.3. Individual Image Data Offset
uint32_t offset = parse_mpf_mpentry(&a, entry->p + i * 16, T);
if (offset)
*out++ = offset;
}
return jv_set(o, jv_string("MP Entry"), a);
}
static jv
parse_mpf_index_ifd(uint32_t **offsets, struct tiffer *T)
{
jv ifd = jv_object();
struct tiffer_entry entry = {};
while (tiffer_next_entry(T, &entry))
ifd = parse_mpf_index_entry(ifd, offsets, T, &entry);
return ifd;
}
static jv
parse_mpf(jv o, const uint8_t ***individuals, const uint8_t *p, size_t len,
const uint8_t *end)
{
struct tiffer T;
if (!tiffer_init(&T, p, len) || !tiffer_next_ifd(&T))
return add_warning(o, "invalid MPF segment");
// First image: IFD0 is Index IFD, any IFD1 is Attribute IFD.
// Other images: IFD0 is Attribute IFD, there is no Index IFD.
uint32_t *offsets = NULL;
if (!*individuals) {
o = add_to_subarray(o, "MPF", parse_mpf_index_ifd(&offsets, &T));
if (!tiffer_next_ifd(&T))
goto out;
}
// This isn't optimal, but it will do.
o = add_to_subarray(o, "MPF", parse_exif_ifd(&T, mpf_entries));
out:
if (offsets) {
size_t count = 0;
for (const uint32_t *i = offsets; *i; i++)
count++;
free(*individuals);
const uint8_t **out = *individuals = calloc(sizeof *out, count + 1);
for (const uint32_t *i = offsets; *i; i++) {
if (*i > end - p)
o = add_warning(o, "MPF offset points past available data");
else
*out++ = p + *i;
}
free(offsets);
}
return o;
}
// --- JPEG --------------------------------------------------------------------
// Because the JPEG file format is simple, just do it manually.
// See: https://www.w3.org/Graphics/JPEG/itu-t81.pdf
enum {
TEM = 0x01,
SOF0 = 0xC0, SOF1, SOF2, SOF3,
DHT = 0xC4,
SOF5, SOF6, SOF7,
JPG = 0xC8,
SOF9, SOF10, SOF11,
DAC = 0xCC,
SOF13, SOF14, SOF15,
RST0 = 0xD0, RST1, RST2, RST3, RST4, RST5, RST6, RST7,
SOI = 0xD8,
EOI = 0xD9,
SOS = 0xDA,
DQT = 0xDB,
DNL = 0xDC,
DRI = 0xDD,
DHP = 0xDE,
EXP = 0xDF,
APP0 = 0xE0, APP1, APP2, APP3, APP4, APP5, APP6, APP7,
APP8, APP9, APP10, APP11, APP12, APP13, APP14, APP15,
JPG0 = 0xF0, JPG1, JPG2, JPG3, JPG4, JPG5, JPG6, JPG7,
JPG8, JPG9, JPG10, JPG11, JPG12, JPG13,
COM = 0xFE
};
// The rest is "RES (Reserved)", except for 0xFF (filler) and 0x00 (invalid).
static const char *marker_ids[0xFF] = {
[TEM] = "TEM",
[SOF0] = "SOF0", [SOF1] = "SOF1", [SOF2] = "SOF2", [SOF3] = "SOF3",
[DHT] = "DHT", [SOF5] = "SOF5", [SOF6] = "SOF6", [SOF7] = "SOF7",
[JPG] = "JPG", [SOF9] = "SOF9", [SOF10] = "SOF10", [SOF11] = "SOF11",
[DAC] = "DAC", [SOF13] = "SOF13", [SOF14] = "SOF14", [SOF15] = "SOF15",
[RST0] = "RST0", [RST1] = "RST1", [RST2] = "RST2", [RST3] = "RST3",
[RST4] = "RST4", [RST5] = "RST5", [RST6] = "RST6", [RST7] = "RST7",
[SOI] = "SOI", [EOI] = "EOI", [SOS] = "SOS", [DQT] = "DQT",
[DNL] = "DNL", [DRI] = "DRI", [DHP] = "DHP", [EXP] = "EXP",
[APP0] = "APP0", [APP1] = "APP1", [APP2] = "APP2", [APP3] = "APP3",
[APP4] = "APP4", [APP5] = "APP5", [APP6] = "APP6", [APP7] = "APP7",
[APP8] = "APP8", [APP9] = "APP9", [APP10] = "APP10", [APP11] = "APP11",
[APP12] = "APP12", [APP13] = "APP13", [APP14] = "APP14", [APP15] = "APP15",
[JPG0] = "JPG0", [JPG1] = "JPG1", [JPG2] = "JPG2", [JPG3] = "JPG3",
[JPG4] = "JPG4", [JPG5] = "JPG5", [JPG6] = "JPG6", [JPG7] = "JPG7",
[JPG8] = "JPG8", [JPG9] = "JPG9", [JPG10] = "JPG10", [JPG11] = "JPG11",
[JPG12] = "JPG12", [JPG13] = "JPG13", [COM] = "COM"
};
// The rest is "RES (Reserved)", except for 0xFF (filler) and 0x00 (invalid).
static const char *marker_descriptions[0xFF] = {
[TEM] = "For temporary private use in arithmetic coding",
[SOF0] = "Baseline DCT",
[SOF1] = "Extended sequential DCT",
[SOF2] = "Progressive DCT",
[SOF3] = "Lossless (sequential)",
[DHT] = "Define Huffman table(s)",
[SOF5] = "Differential sequential DCT",
[SOF6] = "Differential progressive DCT",
[SOF7] = "Differential lossless (sequential)",
[JPG] = "Reserved for JPEG extensions",
[SOF9] = "Extended sequential DCT",
[SOF10] = "Progressive DCT",
[SOF11] = "Lossless (sequential)",
[DAC] = "Define arithmetic coding conditioning(s)",
[SOF13] = "Differential sequential DCT",
[SOF14] = "Differential progressive DCT",
[SOF15] = "Differential lossless (sequential)",
[RST0] = "Restart with module 8 count 0",
[RST1] = "Restart with module 8 count 1",
[RST2] = "Restart with module 8 count 2",
[RST3] = "Restart with module 8 count 3",
[RST4] = "Restart with module 8 count 4",
[RST5] = "Restart with module 8 count 5",
[RST6] = "Restart with module 8 count 6",
[RST7] = "Restart with module 8 count 7",
[SOI] = "Start of image",
[EOI] = "End of image",
[SOS] = "Start of scan",
[DQT] = "Define quantization table(s)",
[DNL] = "Define number of lines",
[DRI] = "Define restart interval",
[DHP] = "Define hierarchical progression",
[EXP] = "Expand reference component(s)",
[APP0] = "Reserved for application segments, 0",
[APP1] = "Reserved for application segments, 1",
[APP2] = "Reserved for application segments, 2",
[APP3] = "Reserved for application segments, 3",
[APP4] = "Reserved for application segments, 4",
[APP5] = "Reserved for application segments, 5",
[APP6] = "Reserved for application segments, 6",
[APP7] = "Reserved for application segments, 7",
[APP8] = "Reserved for application segments, 8",
[APP9] = "Reserved for application segments, 9",
[APP10] = "Reserved for application segments, 10",
[APP11] = "Reserved for application segments, 11",
[APP12] = "Reserved for application segments, 12",
[APP13] = "Reserved for application segments, 13",
[APP14] = "Reserved for application segments, 14",
[APP15] = "Reserved for application segments, 15",
[JPG0] = "Reserved for JPEG extensions, 0",
[JPG1] = "Reserved for JPEG extensions, 1",
[JPG2] = "Reserved for JPEG extensions, 2",
[JPG3] = "Reserved for JPEG extensions, 3",
[JPG4] = "Reserved for JPEG extensions, 4",
[JPG5] = "Reserved for JPEG extensions, 5",
[JPG6] = "Reserved for JPEG extensions, 6",
[JPG7] = "Reserved for JPEG extensions, 7",
[JPG8] = "Reserved for JPEG extensions, 8",
[JPG9] = "Reserved for JPEG extensions, 9",
[JPG10] = "Reserved for JPEG extensions, 10",
[JPG11] = "Reserved for JPEG extensions, 11",
[JPG12] = "Reserved for JPEG extensions, 12",
[JPG13] = "Reserved for JPEG extensions, 13",
[COM] = "Comment",
};
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
struct data {
bool ended;
uint8_t *exif, *icc, *psir;
size_t exif_len, icc_len, psir_len;
int icc_sequence, icc_done;
const uint8_t **mpf_individuals, **mpf_next;
};
static void
parse_append(uint8_t **buffer, size_t *buffer_len, const uint8_t *p, size_t len)
{
size_t buffer_longer = *buffer_len + len;
*buffer = realloc(*buffer, buffer_longer);
memcpy(*buffer + *buffer_len, p, len);
*buffer_len = buffer_longer;
}
static const uint8_t *
parse_marker(uint8_t marker, const uint8_t *p, const uint8_t *end,
struct data *data, jv *o)
{
// Suspected: MJPEG? Undetected format recursion, e.g., thumbnails?
// Found: Random metadata! Multi-Picture Format!
if ((data->ended = marker == EOI)) {
// TODO(p): Handle Exifs independently--flush the last one.
if ((data->mpf_next || (data->mpf_next = data->mpf_individuals)) &&
*data->mpf_next)
return *data->mpf_next++;
if (p != end)
*o = add_warning(*o, "trailing data");
}
// These markers stand alone, not starting a marker segment.
switch (marker) {
case RST0:
case RST1:
case RST2:
case RST3:
case RST4:
case RST5:
case RST6:
case RST7:
*o = add_warning(*o, "unexpected restart marker");
// Fall-through
case SOI:
case EOI:
case TEM:
return p;
}
uint16_t length = p[0] << 8 | p[1];
const uint8_t *payload = p + 2;
if ((p += length) > end) {
*o = add_error(*o, "runaway marker segment");
return NULL;
}
switch (marker) {
case SOF0:
case SOF1:
case SOF2:
case SOF3:
case SOF5:
case SOF6:
case SOF7:
case SOF9:
case SOF10:
case SOF11:
case SOF13:
case SOF14:
case SOF15:
case DHP: // B.2.2 and B.3.2.
// As per B.2.5, Y can be zero, then there needs to be a DNL segment.
*o = add_to_subarray(*o, "info", JV_OBJECT(
jv_string("type"), jv_string(marker_descriptions[marker]),
jv_string("bits"), jv_number(payload[0]),
jv_string("height"), jv_number(payload[1] << 8 | payload[2]),
jv_string("width"), jv_number(payload[3] << 8 | payload[4]),
jv_string("components"), jv_number(payload[5])
));
return p;
}
// See B.1.1.5, we can brute-force our way through the entropy-coded data.
if (marker == SOS) {
while (p + 2 <= end && (p[0] != 0xFF || p[1] < 0xC0 || p[1] > 0xFE ||
(p[1] >= RST0 && p[1] <= RST7)))
p++;
return p;
}
// "The interpretation is left to the application."
if (marker == COM) {
int superascii = 0;
char *buf = calloc(3, p - payload), *bufp = buf;
for (const uint8_t *q = payload; q < p; q++) {
if (*q < 128) {
*bufp++ = *q;
} else {
superascii++;
*bufp++ = 0xC0 | (*q >> 6);
*bufp++ = 0x80 | (*q & 0x3F);
}
}
*bufp++ = 0;
*o = add_to_subarray(*o, "comments", jv_string(buf));
free(buf);
if (superascii)
*o = add_warning(*o, "super-ASCII comments");
}
// These mostly contain an ASCII string header, following JPEG FIF:
//
// "Application-specific APP0 marker segments are identified
// by a zero terminated string which identifies the application
// (not 'JFIF' or 'JFXX')."
if (marker >= APP0 && marker <= APP15) {
const uint8_t *nul = memchr(payload, 0, p - payload);
int unprintable = !nul;
if (nul) {
for (const uint8_t *q = payload; q < nul; q++)
unprintable += *q < 32 || *q >= 127;
}
*o = add_to_subarray(*o, "apps",
unprintable ? jv_null() : jv_string((const char *) payload));
}
// CIPA DC-007-2021 (Multi-Picture Format) 5.2
// https://www.cipa.jp/e/std/std-sec.html
if (marker == APP2 && p - payload >= 8 && !memcmp(payload, "MPF\0", 4)) {
payload += 4;
*o = parse_mpf(*o, &data->mpf_individuals, payload, p - payload, end);
}
// CIPA DC-006 (Stereo Still Image Format for Digital Cameras)
// TODO(p): Handle by properly skipping trailing data (use Stim offsets).
// https://www.w3.org/Graphics/JPEG/jfif3.pdf
if (marker == APP0 && p - payload >= 14 && !memcmp(payload, "JFIF\0", 5)) {
payload += 5;
jv units = jv_number(payload[2]);
switch (payload[2]) {
break; case 0: units = jv_null();
break; case 1: units = jv_string("DPI");
break; case 2: units = jv_string("dots per cm");
}
// The rest is picture data.
*o = add_to_subarray(*o, "JFIF", JV_OBJECT(
jv_string("version"), jv_number(payload[0] * 100 + payload[1]),
jv_string("units"), units,
jv_string("density-x"), jv_number(payload[3] << 8 | payload[4]),
jv_string("density-y"), jv_number(payload[5] << 8 | payload[6]),
jv_string("thumbnail-w"), jv_number(payload[7]),
jv_string("thumbnail-h"), jv_number(payload[8])
));
}
if (marker == APP0 && p - payload >= 6 && !memcmp(payload, "JFXX\0", 5)) {
payload += 5;
jv extension = jv_number(payload[0]);
switch (payload[0]) {
break; case 0x10: extension = jv_string("JPEG thumbnail");
break; case 0x11: extension = jv_string("Paletted thumbnail");
break; case 0x13: extension = jv_string("RGB thumbnail");
}
// The rest is picture data.
*o = add_to_subarray(*o, "JFXX",
JV_OBJECT(jv_string("extension"), extension));
}
// https://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf 4.7.2
// Adobe XMP Specification Part 3: Storage in Files, 2020/1, 1.1.3
if (marker == APP1 && p - payload >= 6 && !memcmp(payload, "Exif\0", 5)) {
payload += 6;
if (payload[-1] != 0)
*o = add_warning(*o, "weirdly padded Exif header");
if (data->exif)
*o = add_warning(*o, "multiple Exif segments");
parse_append(&data->exif, &data->exif_len, payload, p - payload);
}
// https://www.color.org/specification/ICC1v43_2010-12.pdf B.4
if (marker == APP2 && p - payload >= 14 &&
!memcmp(payload, "ICC_PROFILE\0", 12) && !data->icc_done &&
payload[12] == ++data->icc_sequence && payload[13] >= payload[12]) {
payload += 14;
parse_append(&data->icc, &data->icc_len, payload, p - payload);
data->icc_done = payload[-1] == data->icc_sequence;
}
// Adobe XMP Specification Part 3: Storage in Files, 2020/1, 1.1.3 + 3.1.3
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/
if (marker == APP13 && p - payload >= 14 &&
!memcmp(payload, "Photoshop 3.0\0", 14)) {
payload += 14;
parse_append(&data->psir, &data->psir_len, payload, p - payload);
}
// TODO(p): Extract all XMP segments.
return p;
}
static jv
parse_jpeg(jv o, const uint8_t *p, size_t len)
{
struct data data = {};
const uint8_t *end = p + len;
jv markers = jv_array();
while (p) {
// This is an expectable condition, use a simple warning.
if (p + 2 > end) {
if (!data.ended)
o = add_warning(o, "unexpected EOF");
break;
}
if (*p++ != 0xFF || *p == 0) {
if (!data.ended)
o = add_error(o, "no marker found where one was expected");
break;
}
// Markers may be preceded by fill bytes.
if (*p == 0xFF) {
o = jv_object_set(o, jv_string("fillers"), jv_bool(true));
continue;
}
uint8_t marker = *p++;
markers = jv_array_append(markers,
jv_string(marker_ids[marker] ? marker_ids[marker] : "RES"));
p = parse_marker(marker, p, end, &data, &o);
}
if (data.exif) {
// TODO(p): Probably extend it until the end of the JPEG,
// seeing as, e.g., thumbnail data can overflow into follow-up segments.
o = parse_exif(o, data.exif, data.exif_len);
free(data.exif);
}
if (data.icc) {
if (data.icc_done)
o = parse_icc(o, data.icc, data.icc_len);
else
o = add_warning(o, "bad ICC profile sequence");
free(data.icc);
}
if (data.psir) {
o = parse_psir(o, data.psir, data.psir_len);
free(data.psir);
}
free(data.mpf_individuals);
return jv_set(o, jv_string("markers"), markers);
}
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