include/dai/enum.h

   1 /*  This file is part of libDAI - http://www.libdai.org/
   2  *
   3  *  libDAI is licensed under the terms of the GNU General Public License version
   4  *  2, or (at your option) any later version. libDAI is distributed without any
   5  *  warranty. See the file COPYING for more details.
   6  *
   7  *  Copyright (C) 2006-2009  Joris Mooij  [joris dot mooij at libdai dot org]
   8  *  Copyright (C) 2006-2007  Radboud University Nijmegen, The Netherlands
   9  */
  10
  11
  12 /// \file
  13 /// \brief Defines the DAI_ENUM macro
  14
  15
  16 #ifndef __defined_libdai_enum_h
  17 #define __defined_libdai_enum_h
  18
  19
  20 #include <cstring>
  21 #include <iostream>
  22 #include <dai/exceptions.h>
  23
  24
  25 /// Extends the C++ enum type by supporting input/output streaming and conversion to and from const char* and size_t
  26 /** For more details see the source code.
  27  *
  28  *  \par Example:
  29  *  \code
  30  *  DAI_ENUM(colors,RED,GREEN,BLUE)
  31  *  \endcode
  32  *  defines a class \a colors encapsulating an
  33  *  \code
  34  *  enum {RED, GREEN, BLUE};
  35  *  \endcode
  36  *  which offers additional functionality over the plain \c enum keyword.
  37  */
  38 #define DAI_ENUM(x,val0,...) class x {\
  39     public:\
  40         enum value {val0,__VA_ARGS__};\
  41 \
  42         x() : v(val0) {}\
  43 \
  44         x(value w) : v(w) {}\
  45 \
  46         x(char const *w) {\
  47             static char const* labelstring = #val0 "," #__VA_ARGS__;\
  48             size_t pos_begin = 0;\
  49             size_t i = 0;\
  50             for( size_t pos_end = 0; ; pos_end++ ) {\
  51                 if( (labelstring[pos_end] == ',') || (labelstring[pos_end] == '\0') ) {\
  52                     if( (strlen( w ) == pos_end - pos_begin) && (strncmp( labelstring + pos_begin, w, pos_end - pos_begin ) == 0) ) {\
  53                         v = (value)i;\
  54                         return;\
  55                     } else {\
  56                         i++;\
  57                         pos_begin = pos_end + 1;\
  58                     }\
  59                 }\
  60                 if( labelstring[pos_end] == '\0' )\
  61                     break;\
  62             }\
  63             DAI_THROWE(UNKNOWN_ENUM_VALUE,"'" + std::string(w) + "' is not in [" + std::string(labelstring) + "]");\
  64         }\
  65 \
  66         operator value() const { return v; }\
  67 \
  68         operator size_t() const { return (size_t)v; }\
  69 \
  70         operator char const*() const {\
  71             static char labelstring[] = #val0 "," #__VA_ARGS__;\
  72             size_t pos_begin = 0;\
  73             size_t i = 0;\
  74             for( size_t pos_end = 0; ; pos_end++ )\
  75                 if( (labelstring[pos_end] == ',') || (labelstring[pos_end] == '\0') ) {\
  76                     if( (size_t)v == i ) {\
  77                         labelstring[pos_end] = '\0';\
  78                         return labelstring + pos_begin;\
  79                     } else {\
  80                         i++;\
  81                         pos_begin = pos_end + 1;\
  82                     }\
  83                 }\
  84         }\
  85 \
  86         friend std::istream& operator >> (std::istream& is, x& y) {\
  87             std::string s;\
  88             is >> s;\
  89             y = x(s.c_str());\
  90             return is;\
  91         }\
  92 \
  93         friend std::ostream& operator << (std::ostream& os, const x& y) {\
  94             os << (const char *)y;\
  95             return os;\
  96         }\
  97 \
  98     private:\
  99         value v;\
 100 };
 101
 102
 103 #endif