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* and size_t
  37 /** For more details see the source code.
  38  *
  39  *  \par Example:
  40  *  \code
  41  *  DAI_ENUM(colors,RED,GREEN,BLUE)
  42  *  \endcode
  43  *  defines a class \a colors encapsulating an
  44  *  \code
  45  *  enum {RED, GREEN, BLUE};
  46  *  \endcode
  47  *  which offers additional functionality over the plain \c enum keyword.
  48  */
  49 #define DAI_ENUM(x,val0,...) class x {\
  50     public:\
  51         enum value {val0,__VA_ARGS__};\
  52 \
  53         x() : v(val0) {}\
  54 \
  55         x(value w) : v(w) {}\
  56 \
  57         x(char const *w) {\
  58             static char const* labelstring = #val0 "," #__VA_ARGS__ ",";\
  59             size_t pos_begin = 0;\
  60             size_t i = 0;\
  61             for( size_t pos_end = 0; labelstring[pos_end] != '\0'; pos_end++ )\
  62                 if( (labelstring[pos_end] == ',') ) {\
  63                     if( (strlen( w ) == pos_end - pos_begin) && (strncmp( labelstring + pos_begin, w, pos_end - pos_begin ) == 0) ) {\
  64                         v = (value)i;\
  65                         return;\
  66                     } else {\
  67                         i++;\
  68                         pos_begin = pos_end + 1;\
  69                     }\
  70                 }\
  71             DAI_THROW(UNKNOWN_ENUM_VALUE);\
  72         }\
  73 \
  74         operator value() const { return v; }\
  75 \
  76         operator size_t() const { return (size_t)v; }\
  77 \
  78         operator char const*() const {\
  79             static char labelstring[] = #val0 "," #__VA_ARGS__;\
  80             size_t pos_begin = 0;\
  81             size_t i = 0;\
  82             for( size_t pos_end = 0; ; pos_end++ )\
  83                 if( (labelstring[pos_end] == ',') || (labelstring[pos_end] == '\0') ) {\
  84                     if( (size_t)v == i ) {\
  85                         labelstring[pos_end] = '\0';\
  86                         return labelstring + pos_begin;\
  87                     } else {\
  88                         i++;\
  89                         pos_begin = pos_end + 1;\
  90                     }\
  91                 }\
  92         }\
  93 \
  94         friend std::istream& operator >> (std::istream& is, x& y) {\
  95             std::string s;\
  96             is >> s;\
  97             y = x(s.c_str());\
  98             return is;\
  99         }\
 100 \
 101         friend std::ostream& operator << (std::ostream& os, const x& y) {\
 102             os << (const char *)y;\
 103             return os;\
 104         }\
 105 \
 106     private:\
 107         value v;\
 108 };
 109
 110
 111 #endif