Add a most basic tool to inspect ISO BMFF files

This can be massively extended.

tools/.gitignore

@@ -2,3 +2,4 @@
 /jpeginfo
 /tiffinfo
 /webpinfo
+/bmffinfo

tools/Makefile

@@ -5,7 +5,7 @@ CFLAGS = -g -O2 -Wall -Wextra `pkg-config --cflags $(deps)`
 LDLIBS = -ljq `pkg-config --libs $(deps)`
 
 deps = libpng
-targets = pnginfo jpeginfo tiffinfo webpinfo
+targets = pnginfo jpeginfo tiffinfo webpinfo bmffinfo
 
 all: $(targets)
 $(targets): info.h

tools/bmffinfo.c

@@ -0,0 +1,142 @@
+//
+// bmffinfo.c: acquire information about BMFF 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 "info.h"
+
+#include <jv.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+// --- ISO/IEC base media file format ------------------------------------------
+// ISO/IEC 14496-12:2015(E), used to be publicly available, now there's only:
+// https://mpeg.chiariglione.org/standards/mpeg-4/iso-base-media-file-format/text-isoiec-14496-12-5th-edition
+// but people have managed to archive the final version as well:
+// https://b.goeswhere.com/ISO_IEC_14496-12_2015.pdf
+//
+// ISO/IEC 23008-12:2017 Information technology -
+// High efficiency coding and media delivery in heterogeneous environments -
+// Part 12: Image File Format + Cor 1:2020 Technical Corrigendum 1
+// https://standards.iso.org/ittf/PubliclyAvailableStandards/
+
+static jv
+parse_bmff_box(jv o, const char *type, const uint8_t *data, size_t len)
+{
+	// TODO(p): Parse out "uuid"'s uint8_t[16] initial field, present as hex.
+	// TODO(p): Parse out "ftyp" contents: 14496-12:2015 4.3
+	// TODO(p): Parse out other important boxes: 14496-12:2015 8+
+	return add_to_subarray(o, "boxes", jv_string(type));
+}
+
+static jv
+parse_bmff(jv o, const uint8_t *p, size_t len)
+{
+	// 4.2 Object Structure--this box need not be present, nor at the beginning
+	// TODO(p): What does `aligned(8)` mean? It's probably in bits.
+	if (len < 8 || memcmp(p + 4, "ftyp", 4))
+		return add_error(o, "not BMFF at all or unsupported");
+
+	const uint8_t *end = p + len;
+	while (p < end) {
+		if (end - p < 8) {
+			o = add_warning(o, "box framing mismatch");
+			break;
+		}
+
+		char type[5] = "";
+		memcpy(type, p + 4, 4);
+
+		uint64_t box_size = u32be(p);
+		const uint8_t *data = p + 8;
+		if (box_size == 1) {
+			if (end - p < 16) {
+				o = add_warning(o, "unexpected EOF");
+				break;
+			}
+			box_size = u64be(data);
+			data += 8;
+		} else if (!box_size)
+			box_size = end - p;
+
+		if (box_size > (uint64_t) (end - p)) {
+			o = add_warning(o, "unexpected EOF");
+			break;
+		}
+
+		size_t data_len = box_size - (data - p);
+		o = parse_bmff_box(o, type, data, data_len);
+		p += box_size;
+	}
+	return o;
+}
+
+// --- I/O ---------------------------------------------------------------------
+
+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;
+	}
+
+	o = parse_bmff(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[])
+{
+	(void) parse_icc;
+	(void) parse_exif;
+	(void) parse_psir;
+
+	// 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;
+}

tools/info.h

@@ -35,6 +35,14 @@ binhex(const uint8_t *data, size_t len)
 	return buf;
 }
 
+static uint64_t
+u64be(const uint8_t *p)
+{
+	return (uint64_t) p[0] << 56 | (uint64_t) p[1] << 48 |
+		(uint64_t) p[2] << 40 | (uint64_t) p[3] << 32 |
+		(uint64_t) p[4] << 24 | p[5] << 16 | p[6] << 8 | p[7];
+}
+
 static uint32_t
 u32be(const uint8_t *p)
 {
@@ -47,6 +55,14 @@ u16be(const uint8_t *p)
 	return (uint16_t) p[0] << 8 | p[1];
 }
 
+static uint64_t
+u64le(const uint8_t *p)
+{
+	return (uint64_t) p[7] << 56 | (uint64_t) p[6] << 48 |
+		(uint64_t) p[5] << 40 | (uint64_t) p[4] << 32 |
+		(uint64_t) p[3] << 24 | p[2] << 16 | p[1] << 8 | p[0];
+}
+
 static uint32_t
 u32le(const uint8_t *p)
 {
@@ -97,9 +113,10 @@ u16le(const uint8_t *p)
 // ExifTool is too user-oriented.
 
 static struct un {
+	uint64_t (*u64) (const uint8_t *);
 	uint32_t (*u32) (const uint8_t *);
 	uint16_t (*u16) (const uint8_t *);
-} unbe = {u32be, u16be}, unle = {u32le, u16le};
+} unbe = {u64be, u32be, u16be}, unle = {u64le, u32le, u16le};
 
 struct tiffer {
 	struct un *un;

tools/webpinfo.c

@@ -38,7 +38,7 @@ parse_webp(jv o, const uint8_t *p, size_t len)
 
 	// TODO(p): This can still be parseable.
 	// TODO(p): Warn on trailing data.
-	uint32_t size = unle.u32(p + 4);
+	uint32_t size = u32le(p + 4);
 	if (8 + size < len)
 		return add_error(o, "truncated file");
 
@@ -53,7 +53,7 @@ parse_webp(jv o, const uint8_t *p, size_t len)
 			break;
 		}
 
-		uint32_t chunk_size = unle.u32(p + 4);
+		uint32_t chunk_size = u32le(p + 4);
 		uint32_t chunk_advance = (chunk_size + 1) & ~1;
 		if (p + 8 + chunk_advance > end) {
 			o = add_warning(o, "runaway chunk payload");