1 files changed, 142 insertions, 0 deletions
diff --git a/tools/bmffinfo.c b/tools/bmffinfo.c
new file mode 100644
index 0000000..f0c6ff1
--- /dev/null
+++ b/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;
+}