VwNativeCacheWriter.h

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/*
 * Copyright (c) 2009 Yahoo! Inc.  All rights reserved.  The copyrights
 * embodied in the content of this file are licensed under the BSD
 * (revised) open source license.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * Written (W) 2011 Shashwat Lal Das
 * Adaptation of Vowpal Wabbit v5.1.
 * Copyright (C) 2011 Berlin Institute of Technology and Max-Planck-Society.
 */

#ifndef _VW_NATIVECACHE_WRITE_H__
#define _VW_NATIVECACHE_WRITE_H__

#include <shogun/classifier/vw/cache/VwCacheWriter.h>

namespace shogun
{
class CVwNativeCacheWriter: public CVwCacheWriter
{
public:
    CVwNativeCacheWriter();

    CVwNativeCacheWriter(char * fname, CVwEnvironment* env_to_use);

    virtual ~CVwNativeCacheWriter();

    virtual void set_file(int32_t f);

    virtual void cache_example(VwExample* &ex);

    virtual const char* get_name() const { return "VwNativeCacheWriter"; }

private:
    void init();

    void write_header();

    char* run_len_encode(char *p, vw_size_t i);

    inline uint32_t ZigZagEncode(int32_t n)
    {
        uint32_t ret = (n << 1) ^ (n >> 31);

        return ret;
    }

    char* bufcache_label(VwLabel* ld, char* c);

    void cache_label(VwLabel* ld);

    void cache_tag(v_array<char> tag);

    void output_byte(unsigned char s);

    void output_features(unsigned char index, VwFeature* begin, VwFeature* end);

protected:
    CIOBuffer buf;

private:
    vw_size_t neg_1;
    vw_size_t general;
    vw_size_t int_size;
};

}
#endif // _VW_NATIVECACHE_WRITE_H__