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src/Source/LibWebP/src/mux/mux.muxread.c  view on Meta::CPAN

    }
    data_size = ChunkDiskSize(&chunk);
    id = ChunkGetIdFromTag(chunk.tag_);
    switch (id) {
      case WEBP_CHUNK_ALPHA:
        if (wpi->alpha_ != NULL) goto Err;  // Consecutive ALPH chunks.
        if (ChunkSetNth(&chunk, &wpi->alpha_, 1) != WEBP_MUX_OK) goto Err;
        wpi->is_partial_ = 1;  // Waiting for a VP8 chunk.
        break;
      case WEBP_CHUNK_IMAGE:
        if (ChunkSetNth(&chunk, &wpi->img_, 1) != WEBP_MUX_OK) goto Err;
        if (!MuxImageFinalize(wpi)) goto Err;
        wpi->is_partial_ = 0;  // wpi is completely filled.
 PushImage:
        // Add this to mux->images_ list.
        if (MuxImagePush(wpi, &mux->images_) != WEBP_MUX_OK) goto Err;
        MuxImageInit(wpi);  // Reset for reading next image.
        break;
      case WEBP_CHUNK_ANMF:
        if (wpi->is_partial_) goto Err;  // Previous wpi is still incomplete.
        if (!MuxImageParse(&chunk, copy_data, wpi)) goto Err;
        ChunkRelease(&chunk);
        goto PushImage;
        break;
      default:  // A non-image chunk.
        if (wpi->is_partial_) goto Err;  // Encountered a non-image chunk before
                                         // getting all chunks of an image.
        chunk_list = MuxGetChunkListFromId(mux, id);  // List to add this chunk.
        if (ChunkSetNth(&chunk, chunk_list, 0) != WEBP_MUX_OK) goto Err;
        if (id == WEBP_CHUNK_VP8X) {  // grab global specs
          mux->canvas_width_ = GetLE24(data + 12) + 1;
          mux->canvas_height_ = GetLE24(data + 15) + 1;
        }
        break;
    }
    data += data_size;
    size -= data_size;
    ChunkInit(&chunk);
  }

  // Validate mux if complete.
  if (MuxValidate(mux) != WEBP_MUX_OK) goto Err;

  MuxImageDelete(wpi);
  return mux;  // All OK;

 Err:  // Something bad happened.
  ChunkRelease(&chunk);
  MuxImageDelete(wpi);
  WebPMuxDelete(mux);
  return NULL;
}

//------------------------------------------------------------------------------
// Get API(s).

// Validates that the given mux has a single image.
static WebPMuxError ValidateForSingleImage(const WebPMux* const mux) {
  const int num_images = MuxImageCount(mux->images_, WEBP_CHUNK_IMAGE);
  const int num_frames = MuxImageCount(mux->images_, WEBP_CHUNK_ANMF);
  const int num_fragments = MuxImageCount(mux->images_, WEBP_CHUNK_FRGM);

  if (num_images == 0) {
    // No images in mux.
    return WEBP_MUX_NOT_FOUND;
  } else if (num_images == 1 && num_frames == 0 && num_fragments == 0) {
    // Valid case (single image).
    return WEBP_MUX_OK;
  } else {
    // Frame/Fragment case OR an invalid mux.
    return WEBP_MUX_INVALID_ARGUMENT;
  }
}

// Get the canvas width, height and flags after validating that VP8X/VP8/VP8L
// chunk and canvas size are valid.
static WebPMuxError MuxGetCanvasInfo(const WebPMux* const mux,
                                     int* width, int* height, uint32_t* flags) {
  int w, h;
  uint32_t f = 0;
  WebPData data;
  assert(mux != NULL);

  // Check if VP8X chunk is present.
  if (MuxGet(mux, IDX_VP8X, 1, &data) == WEBP_MUX_OK) {
    if (data.size < VP8X_CHUNK_SIZE) return WEBP_MUX_BAD_DATA;
    f = GetLE32(data.bytes + 0);
    w = GetLE24(data.bytes + 4) + 1;
    h = GetLE24(data.bytes + 7) + 1;
  } else {
    const WebPMuxImage* const wpi = mux->images_;
    // Grab user-forced canvas size as default.
    w = mux->canvas_width_;
    h = mux->canvas_height_;
    if (w == 0 && h == 0 && ValidateForSingleImage(mux) == WEBP_MUX_OK) {
      // single image and not forced canvas size => use dimension of first frame
      assert(wpi != NULL);
      w = wpi->width_;
      h = wpi->height_;
    }
    if (wpi != NULL) {
      if (wpi->has_alpha_) f |= ALPHA_FLAG;
    }
  }
  if (w * (uint64_t)h >= MAX_IMAGE_AREA) return WEBP_MUX_BAD_DATA;

  if (width != NULL) *width = w;
  if (height != NULL) *height = h;
  if (flags != NULL) *flags = f;
  return WEBP_MUX_OK;
}

WebPMuxError WebPMuxGetCanvasSize(const WebPMux* mux, int* width, int* height) {
  if (mux == NULL || width == NULL || height == NULL) {
    return WEBP_MUX_INVALID_ARGUMENT;
  }
  return MuxGetCanvasInfo(mux, width, height, NULL);
}

WebPMuxError WebPMuxGetFeatures(const WebPMux* mux, uint32_t* flags) {
  if (mux == NULL || flags == NULL) return WEBP_MUX_INVALID_ARGUMENT;
  return MuxGetCanvasInfo(mux, NULL, NULL, flags);
}

static uint8_t* EmitVP8XChunk(uint8_t* const dst, int width,
                              int height, uint32_t flags) {

src/Source/LibWebP/src/mux/mux.muxread.c  view on Meta::CPAN

  if (data == NULL) return WEBP_MUX_MEMORY_ERROR;

  // Main RIFF header.
  dst = MuxEmitRiffHeader(data, size);

  if (need_vp8x) {
    dst = EmitVP8XChunk(dst, wpi->width_, wpi->height_, ALPHA_FLAG);  // VP8X.
    dst = ChunkListEmit(wpi->alpha_, dst);       // ALPH.
  }

  // Bitstream.
  dst = ChunkListEmit(wpi->img_, dst);
  assert(dst == data + size);

  // Output.
  bitstream->bytes = data;
  bitstream->size = size;
  return WEBP_MUX_OK;
}

WebPMuxError WebPMuxGetChunk(const WebPMux* mux, const char fourcc[4],
                             WebPData* chunk_data) {
  CHUNK_INDEX idx;
  if (mux == NULL || fourcc == NULL || chunk_data == NULL) {
    return WEBP_MUX_INVALID_ARGUMENT;
  }
  idx = ChunkGetIndexFromFourCC(fourcc);
  if (IsWPI(kChunks[idx].id)) {     // An image chunk.
    return WEBP_MUX_INVALID_ARGUMENT;
  } else if (idx != IDX_UNKNOWN) {  // A known chunk type.
    return MuxGet(mux, idx, 1, chunk_data);
  } else {                          // An unknown chunk type.
    const WebPChunk* const chunk =
        ChunkSearchList(mux->unknown_, 1, ChunkGetTagFromFourCC(fourcc));
    if (chunk == NULL) return WEBP_MUX_NOT_FOUND;
    *chunk_data = chunk->data_;
    return WEBP_MUX_OK;
  }
}

static WebPMuxError MuxGetImageInternal(const WebPMuxImage* const wpi,
                                        WebPMuxFrameInfo* const info) {
  // Set some defaults for unrelated fields.
  info->x_offset = 0;
  info->y_offset = 0;
  info->duration = 1;
  info->dispose_method = WEBP_MUX_DISPOSE_NONE;
  info->blend_method = WEBP_MUX_BLEND;
  // Extract data for related fields.
  info->id = ChunkGetIdFromTag(wpi->img_->tag_);
  return SynthesizeBitstream(wpi, &info->bitstream);
}

static WebPMuxError MuxGetFrameFragmentInternal(const WebPMuxImage* const wpi,
                                                WebPMuxFrameInfo* const frame) {
  const int is_frame = (wpi->header_->tag_ == kChunks[IDX_ANMF].tag);
  const CHUNK_INDEX idx = is_frame ? IDX_ANMF : IDX_FRGM;
  const WebPData* frame_frgm_data;
  if (!is_frame) return WEBP_MUX_INVALID_ARGUMENT;
  assert(wpi->header_ != NULL);  // Already checked by WebPMuxGetFrame().
  // Get frame/fragment chunk.
  frame_frgm_data = &wpi->header_->data_;
  if (frame_frgm_data->size < kChunks[idx].size) return WEBP_MUX_BAD_DATA;
  // Extract info.
  frame->x_offset = 2 * GetLE24(frame_frgm_data->bytes + 0);
  frame->y_offset = 2 * GetLE24(frame_frgm_data->bytes + 3);
  if (is_frame) {
    const uint8_t bits = frame_frgm_data->bytes[15];
    frame->duration = GetLE24(frame_frgm_data->bytes + 12);
    frame->dispose_method =
        (bits & 1) ? WEBP_MUX_DISPOSE_BACKGROUND : WEBP_MUX_DISPOSE_NONE;
    frame->blend_method = (bits & 2) ? WEBP_MUX_NO_BLEND : WEBP_MUX_BLEND;
  } else {  // Defaults for unused values.
    frame->duration = 1;
    frame->dispose_method = WEBP_MUX_DISPOSE_NONE;
    frame->blend_method = WEBP_MUX_BLEND;
  }
  frame->id = ChunkGetIdFromTag(wpi->header_->tag_);
  return SynthesizeBitstream(wpi, &frame->bitstream);
}

WebPMuxError WebPMuxGetFrame(
    const WebPMux* mux, uint32_t nth, WebPMuxFrameInfo* frame) {
  WebPMuxError err;
  WebPMuxImage* wpi;

  // Sanity checks.
  if (mux == NULL || frame == NULL) {
    return WEBP_MUX_INVALID_ARGUMENT;
  }

  // Get the nth WebPMuxImage.
  err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, nth, &wpi);
  if (err != WEBP_MUX_OK) return err;

  // Get frame info.
  if (wpi->header_ == NULL) {
    return MuxGetImageInternal(wpi, frame);
  } else {
    return MuxGetFrameFragmentInternal(wpi, frame);
  }
}

WebPMuxError WebPMuxGetAnimationParams(const WebPMux* mux,
                                       WebPMuxAnimParams* params) {
  WebPData anim;
  WebPMuxError err;

  if (mux == NULL || params == NULL) return WEBP_MUX_INVALID_ARGUMENT;

  err = MuxGet(mux, IDX_ANIM, 1, &anim);
  if (err != WEBP_MUX_OK) return err;
  if (anim.size < kChunks[WEBP_CHUNK_ANIM].size) return WEBP_MUX_BAD_DATA;
  params->bgcolor = GetLE32(anim.bytes);
  params->loop_count = GetLE16(anim.bytes + 4);

  return WEBP_MUX_OK;
}

// Get chunk index from chunk id. Returns IDX_NIL if not found.
static CHUNK_INDEX ChunkGetIndexFromId(WebPChunkId id) {