// Copyright 2017 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef SRC_PUFF_READER_H_
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#define SRC_PUFF_READER_H_
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#include <cstddef>
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#include <cstdint>
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#include "puffin/src/include/puffin/common.h"
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#include "puffin/src/puff_data.h"
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namespace puffin {
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// An abstract class for reading data from a puffed buffer. Data can be
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// literals, lengths, distances, or metadata. Extensions of this class can
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// define how the puffed data should reside in the puffed buffer.
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class PuffReaderInterface {
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public:
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virtual ~PuffReaderInterface() = default;
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// Retrieves the next puff data available in the puffed buffer. Similar to
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// |PuffWriterInterface.Insert()| This function does not check for validity of
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// data.
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//
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// |data| OUT The next data available in the puffed buffer.
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virtual bool GetNext(PuffData* data) = 0;
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// Returns the number of bytes left in the puff buffer.
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virtual size_t BytesLeft() const = 0;
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};
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class BufferPuffReader : public PuffReaderInterface {
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public:
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// Sets the parameters of puff buffer.
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//
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// |puff_buf| IN The input puffed stream. It is owned by the caller and must
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// be valid during the lifetime of the object.
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// |puff_size| IN The size of the puffed stream.
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BufferPuffReader(const uint8_t* puff_buf, size_t puff_size)
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: puff_buf_in_(puff_buf),
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puff_size_(puff_size),
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index_(0),
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state_(State::kReadingBlockMetadata) {}
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~BufferPuffReader() override = default;
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bool GetNext(PuffData* pd) override;
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size_t BytesLeft() const override;
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private:
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// The pointer to the puffed stream. This should not be deallocated.
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const uint8_t* puff_buf_in_;
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// The size of the puffed buffer.
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size_t puff_size_;
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// Index to the offset of the next data in the puff buffer.
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size_t index_;
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// State when reading from the puffed buffer.
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enum class State {
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kReadingLenDist = 0,
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kReadingBlockMetadata,
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} state_;
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DISALLOW_COPY_AND_ASSIGN(BufferPuffReader);
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};
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} // namespace puffin
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#endif // SRC_PUFF_READER_H_
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