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/**************************************************************************
*
* Copyright 2011 Zack Rusin
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
**************************************************************************/
#ifndef TRACE_SNAPPYFILE_HPP
#define TRACE_SNAPPYFILE_HPP
#include <assert.h>
#include "trace_file.hpp"
#include <string>
#include <fstream>
namespace snappy {
class File;
}
namespace Trace {
#define SNAPPY_CHUNK_SIZE (1 * 1024 * 1024)
#define SNAPPY_BYTE1 'a'
#define SNAPPY_BYTE2 't'
class SnappyFile : public File {
public:
SnappyFile(const std::string &filename = std::string(),
File::Mode mode = File::Read);
virtual ~SnappyFile();
virtual bool supportsOffsets() const;
virtual File::Offset currentOffset();
virtual void setCurrentOffset(const File::Offset &offset);
protected:
virtual bool rawOpen(const std::string &filename, File::Mode mode);
virtual bool rawWrite(const void *buffer, size_t length);
virtual bool rawRead(void *buffer, size_t length);
virtual int rawGetc();
virtual void rawClose();
virtual void rawFlush();
virtual bool rawSkip(size_t length);
virtual int rawPercentRead();
private:
inline size_t usedCacheSize() const
{
assert(m_cachePtr >= m_cache);
return m_cachePtr - m_cache;
}
inline size_t freeCacheSize() const
{
assert(m_cacheSize >= usedCacheSize());
if (m_cacheSize > 0) {
return m_cacheSize - usedCacheSize();
} else {
return 0;
}
}
inline bool endOfData() const
{
return m_stream.eof() && freeCacheSize() == 0;
}
void flushWriteCache();
void flushReadCache(size_t skipLength = 0);
void createCache(size_t size);
void writeCompressedLength(size_t length);
size_t readCompressedLength();
private:
std::fstream m_stream;
char *m_cache;
char *m_cachePtr;
size_t m_cacheSize;
char *m_compressedCache;
File::Offset m_currentOffset;
std::streampos m_endPos;
};
}
#endif // TRACE_SNAPPYFILE_HPP
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