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// Copyright 2017 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_SKIA_SEGMENT_STREAM_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_IMAGE_DECODERS_SKIA_SEGMENT_STREAM_H_
#include "base/memory/scoped_refptr.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/skia/include/core/SkStream.h"
namespace blink {
class SegmentReader;
class PLATFORM_EXPORT SegmentStream : public SkStream {
public:
explicit SegmentStream(size_t reading_offset = 0);
SegmentStream(const SegmentStream&) = delete;
SegmentStream& operator=(const SegmentStream&) = delete;
SegmentStream(SegmentStream&&);
SegmentStream& operator=(SegmentStream&&);
~SegmentStream() override;
void SetReader(scoped_refptr<SegmentReader>);
// If a buffer has shrunk beyond the point we have read, it has been cleared.
// This allows clients to be aware of when data suddenly disappears.
bool IsCleared() const;
// From SkStream:
size_t read(void* buffer, size_t) override;
size_t peek(void* buffer, size_t) const override;
bool isAtEnd() const override;
bool rewind() override;
bool hasPosition() const override;
size_t getPosition() const override;
bool seek(size_t position) override;
bool move(long offset) override;
bool hasLength() const override;
size_t getLength() const override;
private:
scoped_refptr<SegmentReader> reader_;
size_t position_ = 0;
// Offset inside the wrapped `reader_` where `this` `SkStream` begins. This
// is useful in scenarios where we want an `SkCodec` to decode an image
// embedded in a middle of another data stream - one specific example is PNG
// images embedded inside ICO or BMP images.
//
// Note: the only reason this field is not `const` is supporting mutation in
// the implementation of `operator=`.
size_t reading_offset_ = 0;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_IMAGE_DECODERS_SKIA_SEGMENT_STREAM_H_
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