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// Copyright 2008 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_IMAGE_DECODERS_BMP_BMP_IMAGE_DECODER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_IMAGE_DECODERS_BMP_BMP_IMAGE_DECODER_H_
#include <memory>
#include "third_party/blink/renderer/platform/image-decoders/image_decoder.h"
namespace blink {
class BMPImageReader;
class FastSharedBufferReader;
// This class decodes the BMP image format.
class PLATFORM_EXPORT BMPImageDecoder final : public ImageDecoder {
public:
BMPImageDecoder(AlphaOption, ColorBehavior, wtf_size_t max_decoded_bytes);
~BMPImageDecoder() override;
// ImageDecoder:
String FilenameExtension() const override;
const AtomicString& MimeType() const override;
void OnSetData(scoped_refptr<SegmentReader> data) override;
// CAUTION: SetFailed() deletes |reader_|. Be careful to avoid
// accessing deleted memory, especially when calling this from inside
// BMPImageReader!
bool SetFailed() override;
private:
// ImageDecoder:
void DecodeSize() override;
void Decode(wtf_size_t) override;
// Decodes the image. If |only_size| is true, stops decoding after
// calculating the image size. If decoding fails but there is no more
// data coming, sets the "decode failure" flag.
void Decode(bool only_size);
// Decodes the image. If |only_size| is true, stops decoding after
// calculating the image size. Returns whether decoding succeeded.
bool DecodeHelper(bool only_size);
// Processes the file header at the beginning of the data. Sets
// |img_data_offset| based on the header contents. Returns true if the
// file header could be decoded.
bool ProcessFileHeader(wtf_size_t& img_data_offset);
// Uses |fast_reader| and |buffer| to read the file header into |file_header|.
// Computes |file_type| from the file header. Returns whether there was
// sufficient data available to read the header.
bool GetFileType(const FastSharedBufferReader& fast_reader,
char* buffer,
const char*& file_header,
uint16_t& file_type) const;
// An index into |data_| representing how much we've already decoded.
// Note that this only tracks data _this_ class decodes; once the
// BMPImageReader takes over this will not be updated further.
wtf_size_t decoded_offset_;
// The reader used to do most of the BMP decoding.
std::unique_ptr<BMPImageReader> reader_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_IMAGE_DECODERS_BMP_BMP_IMAGE_DECODER_H_
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