Mux: Add WebPDataInit() and remove WebPImageInfo

Change-Id: If661f7d198e284a103a53a451e9f74805119fcf9

src/mux/muxedit.c

@@ -17,15 +17,6 @@
 extern "C" {
 #endif
 
-// Object to store metadata about images.
-typedef struct {
-  int x_offset_;
-  int y_offset_;
-  int duration_;
-  int width_;
-  int height_;
-} WebPImageInfo;
-
 //------------------------------------------------------------------------------
 // Life of a mux object.
 
@@ -155,7 +146,7 @@ static WebPMuxError CreateFrameTileData(const WebPData* const image,
 static WebPMuxError GetImageData(const WebPData* const bitstream,
                                  WebPData* const image, WebPData* const alpha,
                                  int* const is_lossless) {
-  memset(alpha, 0, sizeof(*alpha));  // Default: no alpha.
+  WebPDataInit(alpha);  // Default: no alpha.
   if (bitstream->size_ < TAG_SIZE ||
       memcmp(bitstream->bytes_, "RIFF", TAG_SIZE)) {
     // It is NOT webp file data. Return input data as is.
@@ -359,7 +350,7 @@ static WebPMuxError MuxPushFrameTileInternal(
   if (err != WEBP_MUX_OK) return err;
   image_tag = is_lossless ? kChunks[IDX_VP8L].tag : kChunks[IDX_VP8].tag;
 
-  memset(&frame_tile, 0, sizeof(frame_tile));
+  WebPDataInit(&frame_tile);
   ChunkInit(&chunk);
   MuxImageInit(&wpi);
 
@@ -506,30 +497,19 @@ WebPMuxError MuxGetImageWidthHeight(const WebPChunk* const image_chunk,
 }
 
 static WebPMuxError GetImageInfo(const WebPMuxImage* const wpi,
-                                 WebPImageInfo* const image_info) {
+                                 int* const x_offset, int* const y_offset,
+                                 int* const duration,
+                                 int* const width, int* const height) {
   const WebPChunk* const image_chunk = wpi->img_;
   const WebPChunk* const frame_tile_chunk = wpi->header_;
-  WebPMuxError err;
-  int x_offset, y_offset, duration;
-  int width, height;
-
-  memset(image_info, 0, sizeof(*image_info));
 
   // Get offsets and duration from FRM/TILE chunk.
-  err = GetFrameTileInfo(frame_tile_chunk, &x_offset, &y_offset, &duration);
+  const WebPMuxError err =
+      GetFrameTileInfo(frame_tile_chunk, x_offset, y_offset, duration);
   if (err != WEBP_MUX_OK) return err;
 
   // Get width and height from VP8/VP8L chunk.
-  err = MuxGetImageWidthHeight(image_chunk, &width, &height);
-  if (err != WEBP_MUX_OK) return err;
-
-  // All OK: fill up image_info.
-  image_info->x_offset_ = x_offset;
-  image_info->y_offset_ = y_offset;
-  image_info->duration_ = duration;
-  image_info->width_    = width;
-  image_info->height_   = height;
-  return WEBP_MUX_OK;
+  return MuxGetImageWidthHeight(image_chunk, width, height);
 }
 
 static WebPMuxError GetImageCanvasWidthHeight(
@@ -537,7 +517,7 @@ static WebPMuxError GetImageCanvasWidthHeight(
     int* const width, int* const height) {
   WebPMuxImage* wpi = NULL;
   assert(mux != NULL);
-  assert(width && height);
+  assert(width != NULL && height != NULL);
 
   wpi = mux->images_;
   assert(wpi != NULL);
@@ -549,17 +529,18 @@ static WebPMuxError GetImageCanvasWidthHeight(
     int64_t image_area = 0;
     // Aggregate the bounding box for animation frames & tiled images.
     for (; wpi != NULL; wpi = wpi->next_) {
-      WebPImageInfo image_info;
-      const WebPMuxError err = GetImageInfo(wpi, &image_info);
-      const int max_x_pos = image_info.x_offset_ + image_info.width_;
-      const int max_y_pos = image_info.y_offset_ + image_info.height_;
+      int x_offset, y_offset, duration, w, h;
+      const WebPMuxError err = GetImageInfo(wpi, &x_offset, &y_offset,
+                                            &duration, &w, &h);
+      const int max_x_pos = x_offset + w;
+      const int max_y_pos = y_offset + h;
       if (err != WEBP_MUX_OK) return err;
-      assert(image_info.x_offset_ < MAX_POSITION_OFFSET);
-      assert(image_info.y_offset_ < MAX_POSITION_OFFSET);
+      assert(x_offset < MAX_POSITION_OFFSET);
+      assert(y_offset < MAX_POSITION_OFFSET);
 
       if (max_x_pos > max_x) max_x = max_x_pos;
       if (max_y_pos > max_y) max_y = max_y_pos;
-      image_area += (image_info.width_ * image_info.height_);
+      image_area += w * h;
     }
     *width = max_x;
     *height = max_y;

src/mux/muxinternal.c

@@ -212,17 +212,23 @@ uint8_t* ChunkListEmit(const WebPChunk* chunk_list, uint8_t* dst) {
 //------------------------------------------------------------------------------
 // Manipulation of a WebPData object.
 
+void WebPDataInit(WebPData* const webp_data) {
+  if (webp_data != NULL) {
+    memset(webp_data, 0, sizeof(*webp_data));
+  }
+}
+
 void WebPDataClear(WebPData* const webp_data) {
   if (webp_data != NULL) {
     free((void*)webp_data->bytes_);
-    memset(webp_data, 0, sizeof(*webp_data));
+    WebPDataInit(webp_data);
   }
 }
 
 int WebPDataCopy(const WebPData* const src, WebPData* const dst) {
   if (src == NULL || dst == NULL) return 0;
 
-  memset(dst, 0, sizeof(*dst));
+  WebPDataInit(dst);
   if (src->bytes_ != NULL && src->size_ != 0) {
     dst->bytes_ = (uint8_t*)malloc(src->size_);
     if (dst->bytes_ == NULL) return 0;

src/mux/muxread.c

@@ -37,7 +37,7 @@ static WebPMuxError MuxGet(const WebPMux* const mux, CHUNK_INDEX idx,
                            uint32_t nth, WebPData* const data) {
   assert(mux != NULL);
   assert(!IsWPI(kChunks[idx].id));
-  memset(data, 0, sizeof(*data));
+  WebPDataInit(data);
 
   SWITCH_ID_LIST(IDX_VP8X, mux->vp8x_);
   SWITCH_ID_LIST(IDX_ICCP, mux->iccp_);

src/webp/mux.h

@@ -100,6 +100,9 @@ typedef struct {
 //------------------------------------------------------------------------------
 // Manipulation of a WebPData object.
 
+// Initializes the contents of the 'webp_data' object with default values.
+WEBP_EXTERN(void) WebPDataInit(WebPData* const webp_data);
+
 // Clears the contents of the 'webp_data' object by calling free(). Does not
 // deallocate the object itself.
 WEBP_EXTERN(void) WebPDataClear(WebPData* const webp_data);