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VwNativeCacheReader.h
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1 /*
2  * Copyright (c) 2009 Yahoo! Inc. All rights reserved. The copyrights
3  * embodied in the content of this file are licensed under the BSD
4  * (revised) open source license.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 3 of the License, or
9  * (at your option) any later version.
10  *
11  * Written (W) 2011 Shashwat Lal Das
12  * Adaptation of Vowpal Wabbit v5.1.
13  * Copyright (C) 2011 Berlin Institute of Technology and Max-Planck-Society.
14  */
15 
16 #ifndef _VW_NATIVECACHE_READ_H__
17 #define _VW_NATIVECACHE_READ_H__
18 
20 
21 namespace shogun
22 {
23 
24 #ifndef DOXYGEN_SHOULD_SKIP_THIS
25 // Packed structure for efficient storage
26 struct one_float
27 {
28  // The float to store
29  float32_t f;
30 } __attribute__((packed));
31 
32 #endif // DOXYGEN_SHOULD_SKIP_THIS
33 
40 {
41 public:
46 
53  CVwNativeCacheReader(char * fname, CVwEnvironment* env_to_use);
54 
61  CVwNativeCacheReader(int32_t f, CVwEnvironment* env_to_use);
62 
66  virtual ~CVwNativeCacheReader();
67 
73  virtual void set_file(int32_t f);
74 
80  virtual bool read_cached_example(VwExample* const ae);
81 
85  void check_cache_metadata();
86 
92  virtual const char* get_name() const { return "VwNativeCacheReader"; }
93 
94 private:
98  void init();
99 
108  char* run_len_decode(char *p, vw_size_t& i);
109 
117  inline int32_t ZigZagDecode(uint32_t n)
118  {
119  return (n >> 1) ^ -static_cast<int32_t>(n & 1);
120  }
121 
130  char* bufread_label(VwLabel* const ld, char* c);
131 
139  vw_size_t read_cached_label(VwLabel* const ld);
140 
148  vw_size_t read_cached_tag(VwExample* const ae);
149 
150 
151 protected:
154 
155 private:
156  // Used while parsing
157  const vw_size_t char_size;
158  vw_size_t neg_1;
159  vw_size_t general;
160 };
161 
162 }
163 #endif // _VW_NATIVECACHE_READ_H__

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