85 lines
2.4 KiB
C++
85 lines
2.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_SnappyFrameUtils_h__
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#define mozilla_SnappyFrameUtils_h__
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#include "mozilla/Attributes.h"
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#include "nsError.h"
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namespace mozilla {
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namespace detail {
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//
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// Utility class providing primitives necessary to build streams based
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// on the snappy compressor. This essentially abstracts the framing format
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// defined in:
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//
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// other-licences/snappy/src/framing_format.txt
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//
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// NOTE: Currently only the StreamIdentifier and CompressedData chunks are
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// supported.
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//
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class SnappyFrameUtils
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{
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public:
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enum ChunkType
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{
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Unknown,
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StreamIdentifier,
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CompressedData,
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UncompressedData,
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Padding,
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Reserved,
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ChunkTypeCount
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};
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static const size_t kChunkTypeLength = 1;
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static const size_t kChunkLengthLength = 3;
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static const size_t kHeaderLength = kChunkTypeLength + kChunkLengthLength;
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static const size_t kStreamIdentifierDataLength = 6;
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static const size_t kCRCLength = 4;
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static nsresult
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WriteStreamIdentifier(char* aDest, size_t aDestLength,
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size_t* aBytesWrittenOut);
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static nsresult
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WriteCompressedData(char* aDest, size_t aDestLength,
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const char* aData, size_t aDataLength,
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size_t* aBytesWrittenOut);
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static nsresult
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ParseHeader(const char* aSource, size_t aSourceLength, ChunkType* aTypeOut,
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size_t* aDataLengthOut);
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static nsresult
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ParseData(char* aDest, size_t aDestLength,
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ChunkType aType, const char* aData, size_t aDataLength,
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size_t* aBytesWrittenOut, size_t* aBytesReadOut);
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static nsresult
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ParseStreamIdentifier(char* aDest, size_t aDestLength,
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const char* aData, size_t aDataLength,
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size_t* aBytesWrittenOut, size_t* aBytesReadOut);
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static nsresult
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ParseCompressedData(char* aDest, size_t aDestLength,
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const char* aData, size_t aDataLength,
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size_t* aBytesWrittenOut, size_t* aBytesReadOut);
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static size_t
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MaxCompressedBufferLength(size_t aSourceLength);
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protected:
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SnappyFrameUtils() { }
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virtual ~SnappyFrameUtils() { }
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};
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} // namespace detail
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} // namespace mozilla
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#endif // mozilla_SnappyFrameUtils_h__
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