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authorPřemysl Eric Janouch <p@janouch.name>2021-12-01 13:04:20 +0100
committerPřemysl Eric Janouch <p@janouch.name>2021-12-01 13:04:43 +0100
commit7b53edd6afcf2ef4aebf777a3b152effdbb82c0e (patch)
tree2bbc3ebd6deb93bf7acdbbc5850dd73c738f1b96
parent9707b6a254bdd38bd56f0eb89c1859c62b090aa2 (diff)
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jpeginfo: parse out ICC profile name and version
-rw-r--r--tools/jpeginfo.c176
1 files changed, 142 insertions, 34 deletions
diff --git a/tools/jpeginfo.c b/tools/jpeginfo.c
index 8e4331a..bd7edc2 100644
--- a/tools/jpeginfo.c
+++ b/tools/jpeginfo.c
@@ -23,7 +23,141 @@
#include <stdbool.h>
#include <stdarg.h>
+// --- 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(jv o, const uint8_t *p, size_t len)
+{
+ // TODO(p): Decode.
+ return o;
+}
+
+// --- ICC profiles ------------------------------------------------------------
+
+static uint32_t
+u32be(const uint8_t *p)
+{
+ return (uint32_t) p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3];
+}
+
+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)
+{
+ // https://www.color.org/ICC_Minor_Revision_for_Web.pdf 6
+ // https://www.color.org/specification/ICC1v43_2010-12.pdf 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));
+}
+
// --- JPEG --------------------------------------------------------------------
+// Because the JPEG file format is simple, just do it manually.
// See: https://www.w3.org/Graphics/JPEG/itu-t81.pdf
enum {
@@ -145,35 +279,11 @@ static const char *marker_descriptions[0xFF] = {
[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;
+ uint8_t *exif, *icc;
size_t exif_len, icc_len;
int icc_sequence, icc_done;
};
@@ -312,8 +422,6 @@ parse_marker(uint8_t marker, const uint8_t *p, const uint8_t *end,
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;
@@ -391,22 +499,22 @@ parse_jpeg(jv o, const uint8_t *p, size_t len)
}
if (data.exif) {
- // TODO(p): Decode.
+ o = parse_exif(o, data.exif, data.exif_len);
free(data.exif);
}
-
if (data.icc) {
- if (data.icc_done) {
- // TODO(p): Decode.
- } else {
+ 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);
}
return jv_set(o, jv_string("markers"), markers);
}
+// --- I/O ---------------------------------------------------------------------
+
static jv
do_file(const char *filename, jv o)
{