add a 'format' field to WebPBitstreamFeatures

Change-Id: I79a688e4c34fb77527127bbdf4bc844efa6aa9a4

examples/dwebp.c

@@ -573,6 +573,10 @@ static const char* const kStatusMessages[] = {
   "UNSUPPORTED_FEATURE", "SUSPENDED", "USER_ABORT", "NOT_ENOUGH_DATA"
 };
 
+static const char* const kFormatType[] = {
+  "unspecified", "lossy", "lossless"
+};
+
 int main(int argc, const char *argv[]) {
   int ok = 0;
   const char *in_file = NULL;
@@ -741,14 +745,18 @@ int main(int argc, const char *argv[]) {
   }
 
   if (out_file != NULL) {
-    fprintf(stderr, "Decoded %s. Dimensions: %d x %d%s. Now saving...\n",
+    fprintf(stderr, "Decoded %s. Dimensions: %d x %d %s. Format: %s. "
+                    "Now saving...\n",
             in_file, output_buffer->width, output_buffer->height,
-            bitstream->has_alpha ? " (with alpha)" : "");
+            bitstream->has_alpha ? " (with alpha)" : "",
+            kFormatType[bitstream->format]);
     ok = SaveOutput(output_buffer, format, out_file);
   } else {
-    fprintf(stderr, "File %s can be decoded (dimensions: %d x %d)%s.\n",
+    fprintf(stderr, "File %s can be decoded "
+                    "(dimensions: %d x %d %s. Format: %s).\n",
             in_file, output_buffer->width, output_buffer->height,
-            bitstream->has_alpha ? " (with alpha)" : "");
+            bitstream->has_alpha ? " (with alpha)" : "",
+            kFormatType[bitstream->format]);
     fprintf(stderr, "Nothing written; "
                     "use -o flag to save the result as e.g. PNG.\n");
   }

src/dec/webp.c

@@ -285,6 +285,7 @@ static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
                                           int* const height,
                                           int* const has_alpha,
                                           int* const has_animation,
+                                          int* const format,
                                           WebPHeaderStructure* const headers) {
   int canvas_width = 0;
   int canvas_height = 0;
@@ -292,6 +293,9 @@ static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
   int image_height = 0;
   int found_riff = 0;
   int found_vp8x = 0;
+  int animation_present = 0;
+  int fragments_present = 0;
+
   VP8StatusCode status;
   WebPHeaderStructure hdrs;
 
@@ -312,8 +316,6 @@ static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
   // Skip over VP8X.
   {
     uint32_t flags = 0;
-    int animation_present;
-    int fragments_present;
     status = ParseVP8X(&data, &data_size, &found_vp8x,
                        &canvas_width, &canvas_height, &flags);
     if (status != VP8_STATUS_OK) {
@@ -328,6 +330,7 @@ static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
     }
     if (has_alpha != NULL) *has_alpha = !!(flags & ALPHA_FLAG);
     if (has_animation != NULL) *has_animation = animation_present;
+    if (format != NULL) *format = 0;   // default = undefined
 
     if (found_vp8x && (animation_present || fragments_present) &&
         headers == NULL) {
@@ -359,6 +362,10 @@ static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
     return VP8_STATUS_BITSTREAM_ERROR;
   }
 
+  if (format != NULL && !(animation_present || fragments_present)) {
+    *format = hdrs.is_lossless ? 2 : 1;
+  }
+
   if (!hdrs.is_lossless) {
     if (data_size < VP8_FRAME_HEADER_SIZE) {
       return VP8_STATUS_NOT_ENOUGH_DATA;
@@ -405,7 +412,8 @@ VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) {
   assert(headers != NULL);
   // fill out headers, ignore width/height/has_alpha.
   status = ParseHeadersInternal(headers->data, headers->data_size,
-                                NULL, NULL, NULL, &has_animation, headers);
+                                NULL, NULL, NULL, &has_animation,
+                                NULL, headers);
   if (status == VP8_STATUS_OK || status == VP8_STATUS_NOT_ENOUGH_DATA) {
     // TODO(jzern): full support of animation frames will require API additions.
     if (has_animation) {
@@ -652,7 +660,6 @@ uint8_t* WebPDecodeYUV(const uint8_t* data, size_t data_size,
 static void DefaultFeatures(WebPBitstreamFeatures* const features) {
   assert(features != NULL);
   memset(features, 0, sizeof(*features));
-  features->bitstream_version = 0;
 }
 
 static VP8StatusCode GetFeatures(const uint8_t* const data, size_t data_size,
@@ -666,7 +673,7 @@ static VP8StatusCode GetFeatures(const uint8_t* const data, size_t data_size,
   return ParseHeadersInternal(data, data_size,
                               &features->width, &features->height,
                               &features->has_alpha, &features->has_animation,
-                              NULL);
+                              &features->format, NULL);
 }
 
 //------------------------------------------------------------------------------

src/webp/decode.h

@@ -20,7 +20,7 @@
 extern "C" {
 #endif
 
-#define WEBP_DECODER_ABI_VERSION 0x0201    // MAJOR(8b) + MINOR(8b)
+#define WEBP_DECODER_ABI_VERSION 0x0202    // MAJOR(8b) + MINOR(8b)
 
 // Note: forward declaring enumerations is not allowed in (strict) C and C++,
 // the types are left here for reference.
@@ -404,9 +404,9 @@ struct WebPBitstreamFeatures {
   int height;         // Height in pixels, as read from the bitstream.
   int has_alpha;      // True if the bitstream contains an alpha channel.
   int has_animation;  // True if the bitstream is an animation.
+  int format;         // 0 = undefined (/mixed), 1 = lossy, 2 = lossless
 
   // Unused for now:
-  int bitstream_version;        // should be 0 for now. TODO(later)
   int no_incremental_decoding;  // if true, using incremental decoding is not
                                 // recommended.
   int rotate;                   // TODO(later)