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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_SnappyFrameUtils_h__
#define mozilla_SnappyFrameUtils_h__
#include <cstddef>
#include "mozilla/Attributes.h"
#include "nsError.h"
namespace mozilla {
namespace detail {
//
// Utility class providing primitives necessary to build streams based
// on the snappy compressor. This essentially abstracts the framing format
// defined in:
//
// other-licences/snappy/src/framing_format.txt
//
// NOTE: Currently only the StreamIdentifier and CompressedData chunks are
// supported.
//
class SnappyFrameUtils {
public:
enum ChunkType {
Unknown,
StreamIdentifier,
CompressedData,
UncompressedData,
Padding,
Reserved,
ChunkTypeCount
};
static const size_t kChunkTypeLength = 1;
static const size_t kChunkLengthLength = 3;
static const size_t kHeaderLength = kChunkTypeLength + kChunkLengthLength;
static const size_t kStreamIdentifierDataLength = 6;
static const size_t kCRCLength = 4;
static nsresult WriteStreamIdentifier(char* aDest, size_t aDestLength,
size_t* aBytesWrittenOut);
static nsresult WriteCompressedData(char* aDest, size_t aDestLength,
const char* aData, size_t aDataLength,
size_t* aBytesWrittenOut);
static nsresult ParseHeader(const char* aSource, size_t aSourceLength,
ChunkType* aTypeOut, size_t* aDataLengthOut);
static nsresult ParseData(char* aDest, size_t aDestLength, ChunkType aType,
const char* aData, size_t aDataLength,
size_t* aBytesWrittenOut, size_t* aBytesReadOut);
static nsresult ParseStreamIdentifier(char* aDest, size_t aDestLength,
const char* aData, size_t aDataLength,
size_t* aBytesWrittenOut,
size_t* aBytesReadOut);
static nsresult ParseCompressedData(char* aDest, size_t aDestLength,
const char* aData, size_t aDataLength,
size_t* aBytesWrittenOut,
size_t* aBytesReadOut);
static size_t MaxCompressedBufferLength(size_t aSourceLength);
protected:
SnappyFrameUtils() = default;
virtual ~SnappyFrameUtils() = default;
};
} // namespace detail
} // namespace mozilla
#endif // mozilla_SnappyFrameUtils_h__
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