// 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_DATA_H_
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#define SRC_PUFF_DATA_H_
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#include <cstddef>
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#include <cstdint>
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#include <functional>
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namespace puffin {
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// Data structure that is exchanged between the |PuffWriterInterface|,
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// |PuffReaderInterface|, |Puffer|, and |Huffer|.
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struct PuffData {
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enum class Type {
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// Used for reading/writing only one literal.
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kLiteral,
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// Used for reading/writing literals.
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kLiterals,
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// Used for reading/writing length/distance pairs.
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kLenDist,
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// Used for reading/writing a buffer as the Huffman table. The
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// implementations should copy the data (located in |metadata|) into puff
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// buffer.
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kBlockMetadata,
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// Used for reading/writing an end of block symbol. End of block can
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// contain the unused bits of data at the end of a deflate stream.
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kEndOfBlock,
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} type;
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// A function that once set, can read raw bytes from whatever its parameters
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// are set. This function reads |count| bytes from |buffer| and advances its
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// read offset forward. The next call to this function will start reading
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// after the last read byte. It returns false if it cannot read or the |count|
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// is larger than what is availabe in the buffer.
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// Used by:
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// PuffData::Type::kLiterals
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std::function<bool(uint8_t* buffer, size_t count)> read_fn;
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// Used by:
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// PuffData::Type::kBlockMetadata
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// PuffData::Type::kEndOfBlock
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// PuffData::Type::kLiterals
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// PuffData::Type::kLenDist
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size_t length;
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// Used by:
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// PuffData::Type::kEndOfBlock
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// PuffData::Type::kLenDist
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size_t distance;
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// Used by:
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// PuffData::Type::kEndOfBlock
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// PuffData::Type::kLiteral
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uint8_t byte;
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// 1: Header size.
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// 3: Lengths of next three arrays.
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// 286: Maximum number of literals/lengths codes lengths.
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// 30: Maximum number of distance codes lengths.
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// 19: Maximum number of header code lengths.
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// Used by:
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// PuffData::Type::kBlockMetadata
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uint8_t block_metadata[1 + 3 + 286 + 30 + 19];
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};
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// The headers for differentiating literals from length/distance pairs.
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constexpr uint8_t kLiteralsHeader = 0x00;
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constexpr uint8_t kLenDistHeader = 0x80;
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} // namespace puffin
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#endif // SRC_PUFF_DATA_H_
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