зеркало из https://github.com/mozilla/gecko-dev.git
70 строки
2.3 KiB
C++
70 строки
2.3 KiB
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_SnappyCompressOutputStream_h__
|
|
#define mozilla_SnappyCompressOutputStream_h__
|
|
|
|
#include "mozilla/Attributes.h"
|
|
#include "mozilla/UniquePtr.h"
|
|
#include "nsCOMPtr.h"
|
|
#include "nsIOutputStream.h"
|
|
#include "nsISupportsImpl.h"
|
|
#include "SnappyFrameUtils.h"
|
|
|
|
namespace mozilla {
|
|
|
|
class SnappyCompressOutputStream MOZ_FINAL : public nsIOutputStream
|
|
, protected detail::SnappyFrameUtils
|
|
{
|
|
public:
|
|
// Maximum compression block size.
|
|
static const size_t kMaxBlockSize;
|
|
|
|
// Construct a new blocking output stream to compress data to
|
|
// the given base stream. The base stream must also be blocking.
|
|
// The compression block size may optionally be set to a value
|
|
// up to kMaxBlockSize.
|
|
explicit SnappyCompressOutputStream(nsIOutputStream* aBaseStream,
|
|
size_t aBlockSize = kMaxBlockSize);
|
|
|
|
// The compression block size. To optimize stream performance
|
|
// try to write to the stream in segments at least this size.
|
|
size_t BlockSize() const;
|
|
|
|
private:
|
|
virtual ~SnappyCompressOutputStream();
|
|
|
|
nsresult FlushToBaseStream();
|
|
nsresult MaybeFlushStreamIdentifier();
|
|
nsresult WriteAll(const char* aBuf, uint32_t aCount,
|
|
uint32_t* aBytesWrittenOut);
|
|
|
|
nsCOMPtr<nsIOutputStream> mBaseStream;
|
|
const size_t mBlockSize;
|
|
|
|
// Buffer holding copied uncompressed data. This must be copied here
|
|
// so that the compression can be performed on a single flat buffer.
|
|
mozilla::UniquePtr<char[]> mBuffer;
|
|
|
|
// The next byte in the uncompressed data to copy incoming data to.
|
|
size_t mNextByte;
|
|
|
|
// Buffer holding the resulting compressed data.
|
|
mozilla::UniquePtr<char[]> mCompressedBuffer;
|
|
size_t mCompressedBufferLength;
|
|
|
|
// The first thing written to the stream must be a stream identifier.
|
|
bool mStreamIdentifierWritten;
|
|
|
|
public:
|
|
NS_DECL_THREADSAFE_ISUPPORTS
|
|
NS_DECL_NSIOUTPUTSTREAM
|
|
};
|
|
|
|
} // namespace mozilla
|
|
|
|
#endif // mozilla_SnappyCompressOutputStream_h__
|