RVLDecompressStream.hpp

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/*==========================================================================
 * Copyright (c) 2004 University of Massachusetts.  All Rights Reserved.
 *
 * Use of the Lemur Toolkit for Language Modeling and Information Retrieval
 * is subject to the terms of the software license set forth in the LICENSE
 * file included with this software, and also available at
 * http://www.lemurproject.org/license.html
 *
 *==========================================================================
 */

#ifndef INDRI_RVLDECOMPRESSSTREAM_HPP
#define INDRI_RVLDECOMPRESSSTREAM_HPP
namespace indri
{
  namespace utility
  {
    
    class RVLDecompressStream {
    private:
      const char* _buffer;
      int _bufferSize;
      const char* _current;

    public:
      RVLDecompressStream( const char* buffer, int size ) {
        _buffer = buffer;
        _bufferSize = size;
        _current = buffer;
      }

      void setBuffer( const char* buffer, int size ) {
        _buffer = buffer;
        _bufferSize = size;
        _current = buffer;
      }

      RVLDecompressStream& operator>> ( INT64& value ) {
        _current = lemur::utility::RVLCompress::decompress_longlong( _current, value );
        assert( _current - _buffer <= _bufferSize );
        return *this;
      }

      RVLDecompressStream& operator>> ( UINT64& value ) {
        _current = lemur::utility::RVLCompress::decompress_longlong( _current, value );
        assert( _current - _buffer <= _bufferSize );
        return *this;
      }

      RVLDecompressStream& operator>> ( int& value ) {
        _current = lemur::utility::RVLCompress::decompress_int( _current, value );
        assert( _current - _buffer <= _bufferSize );    
        return *this;
      }

      RVLDecompressStream& operator>> ( unsigned int& value ) {
        int v;
        _current = lemur::utility::RVLCompress::decompress_int( _current, v );
        value = (unsigned int) v;
        assert( _current - _buffer <= _bufferSize );    
        return *this;
      }

      RVLDecompressStream& operator>> ( float& value ) {
        // doubles aren't compressed
        memcpy( &value, _current, sizeof value );
        _current += sizeof value;
        return *this;
      }

      RVLDecompressStream& operator>> ( char* value ) {
        int length;
        _current = lemur::utility::RVLCompress::decompress_int( _current, length );
        ::memcpy( value, _current, length );
        value[length] = 0;
        _current += length;
        return *this;
      }


      bool done() const {
        return (_current - _buffer) >= _bufferSize;
      }
    };
  }
}

#endif // INDRI_RVLDECOMPRESSSTREAM_HPP

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