Quelle SnappyUncompressInputStream.h Sprache: C

/* -*- 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__

quality100%

¤ Dauer der Verarbeitung: 0.1 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.