| // 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_IMAGE_FETCHER_IOS_WEBP_DECODER_H_ |
| #define COMPONENTS_IMAGE_FETCHER_IOS_WEBP_DECODER_H_ |
| |
| #import <Foundation/Foundation.h> |
| #include <stddef.h> |
| |
| #include <memory> |
| |
| #import "base/mac/scoped_nsobject.h" |
| #include "base/memory/ref_counted.h" |
| #include "third_party/libwebp/src/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); |
| |
| // Returns an NSData object containing the decoded image data of the given |
| // webp_image. Returns nil in case of failure. |
| static NSData* DecodeWebpImage(NSData* webp_image); |
| |
| // Returns true if the given image_data is a WebP image. |
| // |
| // Every WebP file contains a 12 byte file header in the beginning of the |
| // file. |
| // A WebP file header starts with the four ASCII characters "RIFF". The next |
| // four bytes contain the image size and the last four header bytes contain |
| // the four ASCII characters "WEBP". |
| // |
| // WebP file header: |
| // 1 1 |
| // Byte Nr. 0 1 2 3 4 5 6 7 8 9 0 1 |
| // Byte value [ R I F F ? ? ? ? W E B P ] |
| // |
| // For more information see: |
| // https://developers.google.com/speed/webp/docs/riff_container#webp_file_header |
| static bool IsWebpImage(const std::string& image_data); |
| |
| // For tests. |
| static size_t GetHeaderSize(); |
| |
| // Main entry point. |
| void OnDataReceived(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_; |
| std::unique_ptr<WebPIDecoder, WebPIDecoderDeleter> incremental_decoder_; |
| base::scoped_nsobject<NSData> output_buffer_; |
| base::scoped_nsobject<NSMutableData> features_; |
| int has_alpha_; |
| }; |
| |
| } // namespace webp_transcode |
| |
| #endif // COMPONENTS_IMAGE_FETCHER_IOS_WEBP_DECODER_H_ |