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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_WEBP_TRANSCODE_WEBP_DECODER_H_
#define COMPONENTS_WEBP_TRANSCODE_WEBP_DECODER_H_
#import <Foundation/Foundation.h>
#include "base/mac/scoped_nsobject.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "third_party/libwebp/webp/decode.h"
@class NSData;
namespace webp_transcode {
// Decodes a WebP image into either JPEG, PNG or uncompressed TIFF.
class WebpDecoder : public base::RefCountedThreadSafe<WebpDecoder> {
public:
// Format of the decoded image.
// This enum is used for UMA reporting, keep it in sync with the histogram
// definition.
enum DecodedImageFormat { JPEG = 1, PNG, TIFF, DECODED_FORMAT_COUNT };
class Delegate : public base::RefCountedThreadSafe<WebpDecoder::Delegate> {
public:
virtual void OnFinishedDecoding(bool success) = 0;
virtual void SetImageFeatures(size_t total_size, // In bytes.
DecodedImageFormat format) = 0;
virtual void OnDataDecoded(NSData* data) = 0;
protected:
friend class base::RefCountedThreadSafe<WebpDecoder::Delegate>;
virtual ~Delegate() {}
};
explicit WebpDecoder(WebpDecoder::Delegate* delegate);
// For tests.
static size_t GetHeaderSize();
// Main entry point.
void OnDataReceived(const base::scoped_nsobject<NSData>& data);
// Stops the decoding.
void Stop();
private:
struct WebPIDecoderDeleter {
inline void operator()(WebPIDecoder* ptr) const { WebPIDelete(ptr); }
};
enum State { READING_FEATURES, READING_DATA, DONE };
friend class base::RefCountedThreadSafe<WebpDecoder>;
virtual ~WebpDecoder();
// Implements WebP image decoding state machine steps.
void DoReadFeatures(NSData* data);
void DoReadData(NSData* data);
bool DoSendData();
scoped_refptr<WebpDecoder::Delegate> delegate_;
WebPDecoderConfig config_;
WebpDecoder::State state_;
scoped_ptr<WebPIDecoder, WebPIDecoderDeleter> incremental_decoder_;
base::scoped_nsobject<NSData> output_buffer_;
base::scoped_nsobject<NSMutableData> features_;
int has_alpha_;
};
} // namespace webp_transcode
#endif // COMPONENTS_WEBP_TRANSCODE_WEBP_DECODER_H_
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