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// Copyright 2015 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef COBALT_LOADER_IMAGE_IMAGE_DATA_DECODER_H_
#define COBALT_LOADER_IMAGE_IMAGE_DATA_DECODER_H_
#include <memory>
#include <string>
#include <vector>
#include "cobalt/base/debugger_hooks.h"
#include "cobalt/loader/image/image.h"
#include "cobalt/render_tree/resource_provider.h"
#if defined(STARBOARD)
#include "starboard/decode_target.h"
#endif
namespace cobalt {
namespace loader {
namespace image {
// This class is used as a component of ImageDecoder and is intended to be
// sub-classed by specific data decoders, such as JPEG decoders and PNG
// decoders. This class is intended to decode image data based on the type,
// but leaves the responsibility of handling callbacks and producing the final
// image to ImageDecoder.
class ImageDataDecoder {
public:
explicit ImageDataDecoder(render_tree::ResourceProvider* resource_provider,
const base::DebuggerHooks& debugger_hooks);
virtual ~ImageDataDecoder() {}
virtual std::string GetTypeString() const = 0;
void DecodeChunk(const uint8* data, size_t size);
scoped_refptr<Image> FinishAndMaybeReturnImage();
protected:
enum State {
kWaitingForHeader,
kReadLines,
kDone,
kError,
};
// Every subclass of ImageDataDecoder should override this function to do
// the internal decoding. The return value of this function is the number of
// decoded data.
virtual size_t DecodeChunkInternal(const uint8* data, size_t input_byte) = 0;
// Subclass has to override to finalize the decoding and return decoded image.
virtual scoped_refptr<Image> FinishInternal() = 0;
render_tree::ResourceProvider* resource_provider() {
return resource_provider_;
}
const base::DebuggerHooks& debugger_hooks() { return debugger_hooks_; }
void set_state(State state) { state_ = state; }
State state() const { return state_; }
render_tree::PixelFormat pixel_format() const { return pixel_format_; }
// Helper functions used by derived classes to create image and various
// objects to hold decoded image data.
std::unique_ptr<render_tree::ImageData> AllocateImageData(
const math::Size& size, bool has_alpha);
scoped_refptr<Image> CreateStaticImage(
std::unique_ptr<render_tree::ImageData> image_data);
private:
// Called on construction to query the ResourceProvider for the best image
// pixel format to use.
void CalculatePixelFormat();
// |resource_provider_| is used to allocate render_tree::ImageData
render_tree::ResourceProvider* const resource_provider_;
// |debugger_hooks_| is used with CLOG to report errors to the WebDev.
const base::DebuggerHooks& debugger_hooks_;
// |data_buffer_| is used to cache the undecoded data.
std::vector<uint8> data_buffer_;
// Record the current decoding status.
State state_;
// The pixel format that the decoded image data is expected to be in.
render_tree::PixelFormat pixel_format_;
};
} // namespace image
} // namespace loader
} // namespace cobalt
#endif // COBALT_LOADER_IMAGE_IMAGE_DATA_DECODER_H_