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
  26
  27 #ifndef __defined_libdai_enum_h
  28 #define __defined_libdai_enum_h
  29
  30
  31 #include <cstring>
  32 #include <iostream>
  33 #include <dai/exceptions.h>
  34
  35
  36 /// Extends the C++ enum type by supporting input/output streaming and conversion to and from const char*
  37 /** Example of usage:
  38  *  \code
  39  *      DAI_ENUM(colors,RED,GREEN,BLUE)
  40  *  \endcode
  41  *  defines a class encapsulating an
  42  *  \code
  43  *      enum colors {RED, GREEN, BLUE};
  44  *  \endcode
  45  *  It offers additional functionality over the plain "enum" keyword.
  46  */
  47 #define DAI_ENUM(x,val0,...) class x {\
  48     public:\
  49         enum value {val0,__VA_ARGS__};\
  50 \
  51         x() : v(val0) {}\
  52 \
  53         x(value w) : v(w) {}\
  54 \
  55         x(char const *w) {\
  56             static char const* labelstring = #val0 "," #__VA_ARGS__ ",";\
  57             size_t pos_begin = 0;\
  58             size_t i = 0;\
  59             for( size_t pos_end = 0; labelstring[pos_end] != '\0'; pos_end++ )\
  60                 if( (labelstring[pos_end] == ',') ) {\
  61                     if( (strlen( w ) == pos_end - pos_begin) && (strncmp( labelstring + pos_begin, w, pos_end - pos_begin ) == 0) ) {\
  62                         v = (value)i;\
  63                         return;\
  64                     } else {\
  65                         i++;\
  66                         pos_begin = pos_end + 1;\
  67                     }\
  68                 }\
  69             DAI_THROW(UNKNOWN_ENUM_VALUE);\
  70         }\
  71 \
  72         operator value() const { return v; }\
  73 \
  74         operator size_t() const { return (size_t)v; }\
  75 \
  76         operator char const*() const {\
  77             static char labelstring[] = #val0 "," #__VA_ARGS__;\
  78             size_t pos_begin = 0;\
  79             size_t i = 0;\
  80             for( size_t pos_end = 0; ; pos_end++ )\
  81                 if( (labelstring[pos_end] == ',') || (labelstring[pos_end] == '\0') ) {\
  82                     if( (size_t)v == i ) {\
  83                         labelstring[pos_end] = '\0';\
  84                         return labelstring + pos_begin;\
  85                     } else {\
  86                         i++;\
  87                         pos_begin = pos_end + 1;\
  88                     }\
  89                 }\
  90         }\
  91 \
  92         friend std::istream& operator >> (std::istream& is, x& y) {\
  93             std::string s;\
  94             is >> s;\
  95             y = x(s.c_str());\
  96             return is;\
  97         }\
  98 \
  99         friend std::ostream& operator << (std::ostream& os, const x& y) {\
 100             os << (const char *)y;\
 101             return os;\
 102         }\
 103 \
 104     private:\
 105         value v;\
 106 };
 107
 108
 109 #endif