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Extract Exif and ICC profiles from Wuffs

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This commit is contained in:
Přemysl Eric Janouch 2021-11-24 20:12:02 +01:00
parent 2ea2178724
commit 1d2f6243e0
Signed by: p
GPG Key ID: A0420B94F92B9493
1 changed files with 143 additions and 12 deletions
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155
fastiv-io.c
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@ -142,6 +142,83 @@ set_error(GError **error, const char *message)
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
static bool
pull_passthrough(const wuffs_base__more_information *minfo,
wuffs_base__io_buffer *src, wuffs_base__io_buffer *dst, GError **error)
{
wuffs_base__range_ie_u64 r =
wuffs_base__more_information__metadata_raw_passthrough__range(minfo);
if (wuffs_base__range_ie_u64__is_empty(&r))
return true;
// This should currently be zero, because we read files all at once.
uint64_t pos = src->meta.pos;
if (pos > r.min_incl ||
wuffs_base__u64__sat_sub(r.max_excl, pos) > src->meta.wi) {
set_error(error, "metadata is outside the read buffer");
return false;
}
// Mimic WUFFS_BASE__MORE_INFORMATION__FLAVOR__METADATA_RAW_TRANSFORM.
*dst = wuffs_base__make_io_buffer(src->data,
wuffs_base__make_io_buffer_meta(
wuffs_base__u64__sat_sub(r.max_excl, pos),
wuffs_base__u64__sat_sub(r.min_incl, pos), pos, TRUE));
// Seeking to the end of it seems to be a requirement in decode_gif.wuffs.
// Just not in case the block was empty. :^)
src->meta.ri = dst->meta.wi;
return true;
}
static GByteArray *
pull_metadata(wuffs_base__image_decoder *dec, wuffs_base__io_buffer *src,
wuffs_base__more_information *minfo, GError **error)
{
uint8_t buf[8192] = {};
GByteArray *array = g_byte_array_new();
while (true) {
*minfo = wuffs_base__empty_more_information();
wuffs_base__io_buffer dst = wuffs_base__ptr_u8__writer(buf, sizeof buf);
wuffs_base__status status =
wuffs_base__image_decoder__tell_me_more(dec, &dst, minfo, src);
switch (minfo->flavor) {
case 0:
// Most likely as a result of an error, we'll handle that below.
case WUFFS_BASE__MORE_INFORMATION__FLAVOR__METADATA_RAW_TRANSFORM:
// Wuffs is reading it into the buffer.
case WUFFS_BASE__MORE_INFORMATION__FLAVOR__METADATA_PARSED:
// Use Wuffs accessor functions in the caller.
break;
default:
set_error(error, "Wuffs metadata API incompatibility");
goto fail;
case WUFFS_BASE__MORE_INFORMATION__FLAVOR__METADATA_RAW_PASSTHROUGH:
// The insane case: error checking really should come first,
// and it can say "even more information". See decode_gif.wuffs.
if (!pull_passthrough(minfo, src, &dst, error))
goto fail;
}
g_byte_array_append(array,
wuffs_base__io_buffer__reader_pointer(&dst),
wuffs_base__io_buffer__reader_length(&dst));
if (wuffs_base__status__is_ok(&status))
return array;
if (status.repr != wuffs_base__suspension__even_more_information &&
status.repr != wuffs_base__suspension__short_write) {
set_error(error, wuffs_base__status__message(&status));
goto fail;
}
}
fail:
g_byte_array_unref(array);
return NULL;
}
// https://github.com/google/wuffs/blob/main/example/gifplayer/gifplayer.c
// is pure C, and a good reference. I can't use the auxiliary libraries,
// since they depend on C++, which is undesirable.
@ -149,16 +226,59 @@ static cairo_surface_t *
open_wuffs(
wuffs_base__image_decoder *dec, wuffs_base__io_buffer src, GError **error)
{
wuffs_base__image_config cfg;
wuffs_base__status status =
wuffs_base__image_decoder__decode_image_config(dec, &cfg, &src);
if (!wuffs_base__status__is_ok(&status)) {
set_error(error, wuffs_base__status__message(&status));
return NULL;
cairo_surface_t *result = NULL;
// TODO(p): PNG also has sRGB and gAMA, as well as text chunks (Wuffs #58).
// The former two use WUFFS_BASE__MORE_INFORMATION__FLAVOR__METADATA_PARSED.
GBytes *meta_exif = NULL;
wuffs_base__image_decoder__set_report_metadata(
dec, WUFFS_BASE__FOURCC__EXIF, true);
GBytes *meta_iccp = NULL;
wuffs_base__image_decoder__set_report_metadata(
dec, WUFFS_BASE__FOURCC__ICCP, true);
wuffs_base__image_config cfg = {};
wuffs_base__status status = {};
while (true) {
status = wuffs_base__image_decoder__decode_image_config(
dec, &cfg, &src);
if (wuffs_base__status__is_ok(&status))
break;
if (status.repr != wuffs_base__note__metadata_reported) {
set_error(error, wuffs_base__status__message(&status));
goto fail_preread;
}
wuffs_base__more_information minfo = {};
GByteArray *buffer = NULL;
if (!(buffer = pull_metadata(dec, &src, &minfo, error)))
goto fail_preread;
switch (wuffs_base__more_information__metadata__fourcc(&minfo)) {
case WUFFS_BASE__FOURCC__EXIF:
if (meta_exif) {
g_warning("ignoring repeated Exif");
break;
}
meta_exif = g_byte_array_free_to_bytes(buffer);
continue;
case WUFFS_BASE__FOURCC__ICCP:
if (meta_iccp) {
g_warning("ignoring repeated ICC profile");
break;
}
meta_iccp = g_byte_array_free_to_bytes(buffer);
continue;
}
g_byte_array_unref(buffer);
}
if (!wuffs_base__image_config__is_valid(&cfg)) {
set_error(error, "invalid Wuffs image configuration");
return NULL;
goto fail_preread;
}
// We need to check because of the Cairo API.
@ -166,7 +286,7 @@ open_wuffs(
uint32_t height = wuffs_base__pixel_config__height(&cfg.pixcfg);
if (width > INT_MAX || height > INT_MAX) {
set_error(error, "image dimensions overflow");
return NULL;
goto fail_preread;
}
// Wuffs maps tRNS to BGRA in `decoder.decode_trns?`, we should be fine.
@ -225,12 +345,12 @@ open_wuffs(
workbuf = wuffs_base__malloc_slice_u8(malloc, workbuf_len_max_incl);
if (!workbuf.ptr) {
set_error(error, "failed to allocate a work buffer");
return NULL;
goto fail_preread;
}
}
unsigned char *targetbuf = NULL;
cairo_surface_t *result = NULL, *surface =
cairo_surface_t *surface =
cairo_image_surface_create(cairo_format, width, height);
cairo_status_t surface_status = cairo_surface_status(surface);
if (surface_status != CAIRO_STATUS_SUCCESS) {
@ -319,12 +439,23 @@ open_wuffs(
// Pixel data has been written, need to let Cairo know.
cairo_surface_mark_dirty((result = surface));
if (meta_exif)
cairo_surface_set_user_data(surface, &fastiv_io_key_exif,
g_bytes_ref(meta_exif), (cairo_destroy_func_t) g_bytes_unref);
if (meta_iccp)
cairo_surface_set_user_data(surface, &fastiv_io_key_icc,
g_bytes_ref(meta_iccp), (cairo_destroy_func_t) g_bytes_unref);
fail:
if (!result)
cairo_surface_destroy(surface);
g_free(targetbuf);
free(workbuf.ptr);
fail_preread:
g_clear_pointer(&meta_exif, g_bytes_unref);
g_clear_pointer(&meta_iccp, g_bytes_unref);
return result;
}
@ -436,14 +567,14 @@ parse_jpeg_metadata(cairo_surface_t *surface, const gchar *data, gsize len)
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);
(cairo_destroy_func_t) g_bytes_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);
(cairo_destroy_func_t) g_bytes_unref);
else
g_byte_array_free(icc, TRUE);
}