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fiv/tools/jpeginfo.c

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//
// jpeginfo.c: acquire information about JPEG files in JSON format
//
// 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 <errno.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <stdarg.h>
// --- JPEG --------------------------------------------------------------------
// 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",
};
// --- Analysis ----------------------------------------------------------------
// Because the JPEG file format is simple, just do it manually.
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));
}
struct data {
bool ended;
char *exif, *icc;
size_t exif_len, icc_len;
int icc_sequence, icc_done;
};
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) && 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 (Multi-Picture Format)
// http://fileformats.archiveteam.org/wiki/Multi-Picture_Format
// TODO(p): Handle by properly skipping trailing data (use MPF offsets).
// CIPA DC-006 (Stereo Still Image Format for Digital Cameras)
// http://fileformats.archiveteam.org/wiki/Multi-Picture_Format
// 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])
));
}
// https://www.w3.org/Graphics/JPEG/jfif3.pdf
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
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 Exifs");
} else {
data->exif = realloc(data->exif, (data->exif_len = p - payload));
memcpy(data->exif, payload, data->exif_len);
}
}
// 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;
size_t icc_longer = data->icc_len + (p - payload);
data->icc = realloc(data->icc, icc_longer);
memcpy(data->icc + data->icc_len, payload, p - payload);
data->icc_len = icc_longer;
data->icc_done = payload[-1] == data->icc_sequence;
}
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) {
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): Decode.
free(data.exif);
}
if (data.icc) {
if (data.icc_done) {
// TODO(p): Decode.
} else {
o = add_warning(o, "bad ICC profile sequence");
}
free(data.icc);
}
return jv_set(o, jv_string("markers"), markers);
}
static jv
do_file(const char *filename, jv o)
{
const char *err = NULL;
FILE *fp = fopen(filename, "rb");
if (!fp) {
err = strerror(errno);
goto error;
}
uint8_t *data = NULL, buf[256 << 10];
size_t n, len = 0;
while ((n = fread(buf, sizeof *buf, sizeof buf / sizeof *buf, fp))) {
data = realloc(data, len + n);
memcpy(data + len, buf, n);
len += n;
}
if (ferror(fp)) {
err = strerror(errno);
goto error_read;
}
#if 0
// Not sure if I want to ensure their existence...
o = jv_object_set(o, jv_string("info"), jv_array());
o = jv_object_set(o, jv_string("warnings"), jv_array());
#endif
o = parse_jpeg(o, data, len);
error_read:
fclose(fp);
free(data);
error:
if (err)
o = add_error(o, err);
return o;
}
int
main(int argc, char *argv[])
{
// XXX: Can't use `xargs -P0`, there's a risk of non-atomic writes.
// Usage: find . -iname *.png -print0 | xargs -0 ./pnginfo
for (int i = 1; i < argc; i++) {
const char *filename = argv[i];
jv o = jv_object();
o = jv_object_set(o, jv_string("filename"), jv_string(filename));
o = do_file(filename, o);
jv_dumpf(o, stdout, 0 /* Might consider JV_PRINT_SORTED. */);
fputc('\n', stdout);
}
return 0;
}
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