include/dai/enum.h

   1 /*  Copyright (C) 2006-2008  Joris Mooij  [joris dot mooij at tuebingen dot mpg dot de]
   2     Radboud University Nijmegen, The Netherlands /
   3     Max Planck Institute for Biological Cybernetics, Germany
   4
   5     This file is part of libDAI.
   6
   7     libDAI is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     libDAI is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with libDAI; if not, write to the Free Software
  19     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20 */
  21
  22
  23 /// \file
  24 /// \brief Defines the DAI_ENUM macro
  25 /// \todo Improve documentation
  26
  27
  28 #ifndef __defined_libdai_enum_h
  29 #define __defined_libdai_enum_h
  30
  31
  32 #include <cstring>
  33 #include <iostream>
  34 #include <dai/exceptions.h>
  35
  36
  37 /// Extends the C++ enum type by supporting input/output streaming and conversion to and from const char*
  38 /** Example of usage:
  39  *  \code
  40  *      DAI_ENUM(colors,RED,GREEN,BLUE)
  41  *  \endcode
  42  *  defines a class encapsulating an
  43  *  \code
  44  *      enum colors {RED, GREEN, BLUE};
  45  *  \endcode
  46  *  It offers additional functionality over the plain "enum" keyword.
  47  */
  48 #define DAI_ENUM(x,val0,...) class x {\
  49     public:\
  50         enum value {val0,__VA_ARGS__};\
  51 \
  52         x() : v(val0) {}\
  53 \
  54         x(value w) : v(w) {}\
  55 \
  56         x(char const *w) {\
  57             static char const* labelstring = #val0 "," #__VA_ARGS__ ",";\
  58             size_t pos_begin = 0;\
  59             size_t i = 0;\
  60             for( size_t pos_end = 0; labelstring[pos_end] != '\0'; pos_end++ )\
  61                 if( (labelstring[pos_end] == ',') ) {\
  62                     if( (strlen( w ) == pos_end - pos_begin) && (strncmp( labelstring + pos_begin, w, pos_end - pos_begin ) == 0) ) {\
  63                         v = (value)i;\
  64                         return;\
  65                     } else {\
  66                         i++;\
  67                         pos_begin = pos_end + 1;\
  68                     }\
  69                 }\
  70             DAI_THROW(UNKNOWN_ENUM_VALUE);\
  71         }\
  72 \
  73         operator value() const { return v; }\
  74 \
  75         operator size_t() const { return (size_t)v; }\
  76 \
  77         operator char const*() const {\
  78             static char labelstring[] = #val0 "," #__VA_ARGS__;\
  79             size_t pos_begin = 0;\
  80             size_t i = 0;\
  81             for( size_t pos_end = 0; ; pos_end++ )\
  82                 if( (labelstring[pos_end] == ',') || (labelstring[pos_end] == '\0') ) {\
  83                     if( (size_t)v == i ) {\
  84                         labelstring[pos_end] = '\0';\
  85                         return labelstring + pos_begin;\
  86                     } else {\
  87                         i++;\
  88                         pos_begin = pos_end + 1;\
  89                     }\
  90                 }\
  91         }\
  92 \
  93         friend std::istream& operator >> (std::istream& is, x& y) {\
  94             std::string s;\
  95             is >> s;\
  96             y = x(s.c_str());\
  97             return is;\
  98         }\
  99 \
 100         friend std::ostream& operator << (std::ostream& os, const x& y) {\
 101             os << (const char *)y;\
 102             return os;\
 103         }\
 104 \
 105     private:\
 106         value v;\
 107 };
 108
 109
 110 #endif