diff options
| -rw-r--r-- | tools/jpeginfo.c | 176 |
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) { |