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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_SnappyUncompressInputStream_h__
#define mozilla_SnappyUncompressInputStream_h__
#include "mozilla/Attributes.h"
#include "mozilla/UniquePtr.h"
#include "nsCOMPtr.h"
#include "nsIInputStream.h"
#include "nsISupportsImpl.h"
#include "SnappyFrameUtils.h"
namespace mozilla {
class SnappyUncompressInputStream final : public nsIInputStream
, protected detail::SnappyFrameUtils
{
public:
// Construct a new blocking stream to uncompress the given base stream. The
// base stream must also be blocking. The base stream does not have to be
// buffered.
explicit SnappyUncompressInputStream(nsIInputStream* aBaseStream);
private:
virtual ~SnappyUncompressInputStream();
// Parse the next chunk of data. This may populate mBuffer and set
// mBufferFillSize. This should not be called when mBuffer already
// contains data.
nsresult ParseNextChunk(uint32_t* aBytesReadOut);
// Convenience routine to Read() from the base stream until we get
// the given number of bytes or reach EOF.
//
// aBuf - The buffer to write the bytes into.
// aCount - Max number of bytes to read. If the stream closes
// fewer bytes my be read.
// aMinValidCount - A minimum expected number of bytes. If we find
// fewer than this many bytes, then return
// NS_ERROR_CORRUPTED_CONTENT. If nothing was read due
// due to EOF (aBytesReadOut == 0), then NS_OK is returned.
// aBytesReadOut - An out parameter indicating how many bytes were read.
nsresult ReadAll(char* aBuf, uint32_t aCount, uint32_t aMinValidCount,
uint32_t* aBytesReadOut);
// Convenience routine to determine how many bytes of uncompressed data
// we currently have in our buffer.
size_t UncompressedLength() const;
nsCOMPtr<nsIInputStream> mBaseStream;
// Buffer to hold compressed data. Must copy here since we need a large
// flat buffer to run the uncompress process on. Always the same length
// of SnappyFrameUtils::MaxCompressedBufferLength(snappy::kBlockSize)
// bytes long.
mozilla::UniquePtr<char[]> mCompressedBuffer;
// Buffer storing the resulting uncompressed data. Exactly snappy::kBlockSize
// bytes long.
mozilla::UniquePtr<char[]> mUncompressedBuffer;
// Number of bytes of uncompressed data in mBuffer.
size_t mUncompressedBytes;
// Next byte of mBuffer to return in ReadSegments(). Must be less than
// mBufferFillSize
size_t mNextByte;
// Next chunk in the stream that has been parsed during read-ahead.
ChunkType mNextChunkType;
// Length of next chunk's length that has been determined during read-ahead.
size_t mNextChunkDataLength;
// The stream must begin with a StreamIdentifier chunk. Are we still
// expecting it?
bool mNeedFirstStreamIdentifier;
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIINPUTSTREAM
};
} // namespace mozilla
#endif // mozilla_SnappyUncompressInputStream_h__
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