diff options
| -rw-r--r-- | fastiv-io.c | 91 | ||||
| -rw-r--r-- | fastiv-io.h | 3 |
2 files changed, 94 insertions, 0 deletions
diff --git a/fastiv-io.c b/fastiv-io.c index fd956ef..95c32fc 100644 --- a/fastiv-io.c +++ b/fastiv-io.c @@ -361,6 +361,93 @@ trivial_cmyk_to_bgra(unsigned char *p, int len) } } +static void +parse_jpeg_metadata(cairo_surface_t *surface, const gchar *data, gsize len) +{ + // Because the JPEG file format is simple, just do it manually. + // See: https://www.w3.org/Graphics/JPEG/itu-t81.pdf + enum { + APP0 = 0xE0, + APP1, + APP2, + RST0 = 0xD0, + RST1, + RST2, + RST3, + RST4, + RST5, + RST6, + RST7, + SOI = 0xD8, + EOI = 0xD9, + SOS = 0xDA, + TEM = 0x01, + }; + + GByteArray *exif = g_byte_array_new(), *icc = g_byte_array_new(); + int icc_sequence = 0, icc_done = FALSE; + + const guint8 *p = (const guint8 *) data, *end = p + len; + while (p + 3 < end && *p++ == 0xFF && *p != SOS && *p != EOI) { + // The previous byte is a fill byte, restart. + if (*p == 0xFF) + continue; + + // These markers stand alone, not starting a marker segment. + guint8 marker = *p++; + switch (marker) { + case RST0: + case RST1: + case RST2: + case RST3: + case RST4: + case RST5: + case RST6: + case RST7: + case SOI: + case TEM: + continue; + } + + // Do not bother validating the structure. + guint16 length = p[0] << 8 | p[1]; + const guint8 *payload = p + 2; + if ((p += length) > end) + break; + + // https://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf 4.7.2 + // Do not check the padding byte. + if (marker == APP1 && p - payload >= 6 && + !memcmp(payload, "Exif\0", 5) && !exif->len) { + payload += 6; + g_byte_array_append(exif, payload, p - payload); + } + + // https://www.color.org/specification/ICC1v43_2010-12.pdf B.4 + if (marker == APP2 && p - payload >= 14 && + !memcmp(payload, "ICC_PROFILE\0", 12) && !icc_done && + payload[12] == ++icc_sequence && payload[13] >= payload[12]) { + payload += 14; + g_byte_array_append(icc, payload, p - payload); + icc_done = payload[-1] == icc_sequence; + } + } + + if (exif->len) + cairo_surface_set_user_data(surface, &fastiv_io_key_exif, + g_byte_array_free_to_bytes(exif), + (cairo_destroy_func_t) g_byte_array_unref); + else + g_byte_array_free(exif, TRUE); + + if (icc_done) + cairo_surface_set_user_data(surface, &fastiv_io_key_icc, + g_byte_array_free_to_bytes(icc), + (cairo_destroy_func_t) g_byte_array_unref); + else + g_byte_array_free(icc, TRUE); +} + static cairo_surface_t * open_libjpeg_turbo(const gchar *data, gsize len, GError **error) { @@ -417,6 +504,7 @@ open_libjpeg_turbo(const gchar *data, gsize len, GError **error) cairo_surface_mark_dirty(surface); tjDestroy(dec); + parse_jpeg_metadata(surface, data, len); return surface; } @@ -764,6 +852,9 @@ open_gdkpixbuf(const gchar *data, gsize len, GError **error) #endif // HAVE_GDKPIXBUF ------------------------------------------------------ +cairo_user_data_key_t fastiv_io_key_exif; +cairo_user_data_key_t fastiv_io_key_icc; + cairo_surface_t * fastiv_io_open(const gchar *path, GError **error) { diff --git a/fastiv-io.h b/fastiv-io.h index d4fe58e..aa21a33 100644 --- a/fastiv-io.h +++ b/fastiv-io.h @@ -52,6 +52,9 @@ typedef struct _FastivIoThumbnailSizeInfo { extern FastivIoThumbnailSizeInfo fastiv_io_thumbnail_sizes[FASTIV_IO_THUMBNAIL_SIZE_COUNT]; +extern cairo_user_data_key_t fastiv_io_key_exif; +extern cairo_user_data_key_t fastiv_io_key_icc; + cairo_surface_t *fastiv_io_open(const gchar *path, GError **error); cairo_surface_t *fastiv_io_open_from_data( const char *data, size_t len, const gchar *path, GError **error); |