jpeg_reader.h

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/*
 * Copyright 2010 Google Inc.
 *
 * 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 PAGESPEED_KERNEL_IMAGE_JPEG_READER_H_
#define PAGESPEED_KERNEL_IMAGE_JPEG_READER_H_

#include <cstddef>
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/image/image_util.h"
#include "pagespeed/kernel/image/scanline_interface.h"
#include "pagespeed/kernel/image/scanline_status.h"

struct jpeg_decompress_struct;
struct jpeg_error_mgr;

namespace net_instaweb {
class MessageHandler;
}

namespace pagespeed {

namespace image_compression {

using net_instaweb::MessageHandler;

struct JpegEnv;

class JpegReader {
 public:
  explicit JpegReader(MessageHandler* handler);
  ~JpegReader();

  jpeg_decompress_struct *decompress_struct() const { return jpeg_decompress_; }

  void PrepareForRead(const void* image_data, size_t image_length);

 private:
  jpeg_decompress_struct *jpeg_decompress_;
  jpeg_error_mgr *decompress_error_;
  MessageHandler* message_handler_;

  
};

class JpegScanlineReader : public ScanlineReaderInterface {
 public:
  explicit JpegScanlineReader(MessageHandler* handler);
  virtual ~JpegScanlineReader();
  virtual bool Reset();

  virtual ScanlineStatus InitializeWithStatus(const void* image_buffer,
                                              size_t buffer_length);

  virtual ScanlineStatus ReadNextScanlineWithStatus(void** out_scanline_bytes);

  virtual size_t GetBytesPerScanline() { return bytes_per_row_; }

  virtual bool HasMoreScanLines() { return (row_ < height_); }
  virtual PixelFormat GetPixelFormat() { return pixel_format_; }
  virtual size_t GetImageHeight() { return height_; }
  virtual size_t GetImageWidth() {  return width_; }
  virtual bool IsProgressive() { return is_progressive_; }

 private:
  JpegEnv* jpeg_env_; 
  unsigned char* row_pointer_[1]; 
  PixelFormat pixel_format_;
  size_t height_;
  size_t width_;
  size_t row_;
  size_t bytes_per_row_;
  bool was_initialized_;
  bool is_progressive_;
  MessageHandler* message_handler_;

  
};

}  

}  

#endif