include/dai/enum.h

   1 /*  This file is part of libDAI - http://www.libdai.org/
   2  *
   3  *  Copyright (c) 2006-2011, The libDAI authors. All rights reserved.
   4  *
   5  *  Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
   6  */
   7
   8
   9 /// \file
  10 /// \brief Defines the DAI_ENUM macro, which can be used to define an \c enum with additional functionality.
  11
  12
  13 #ifndef __defined_libdai_enum_h
  14 #define __defined_libdai_enum_h
  15
  16
  17 #include <cstring>
  18 #include <iostream>
  19 #include <dai/exceptions.h>
  20
  21
  22 /// Extends the C++ \c enum type by supporting input/output streaming and conversion to and from <tt>const char*</tt> and \c size_t
  23 /** For more details see the source code.
  24  *
  25  *  \par Example:
  26  *  \code
  27  *  DAI_ENUM(colors,RED,GREEN,BLUE)
  28  *  \endcode
  29  *  defines a class \a colors encapsulating an
  30  *  \code
  31  *  enum {RED, GREEN, BLUE};
  32  *  \endcode
  33  *  which offers additional functionality over the plain \c enum keyword.
  34  */
  35 #define DAI_ENUM(x,val0,...) class x {\
  36     public:\
  37         enum value {val0,__VA_ARGS__};\
  38 \
  39         x() : v(val0) {}\
  40 \
  41         x(value w) : v(w) {}\
  42 \
  43         x(char const *w) {\
  44             static char const* labelstring = #val0 "," #__VA_ARGS__;\
  45             size_t pos_begin = 0;\
  46             size_t i = 0;\
  47             for( size_t pos_end = 0; ; pos_end++ ) {\
  48                 if( (labelstring[pos_end] == ',') || (labelstring[pos_end] == '\0') ) {\
  49                     if( (strlen( w ) == pos_end - pos_begin) && (strncmp( labelstring + pos_begin, w, pos_end - pos_begin ) == 0) ) {\
  50                         v = (value)i;\
  51                         return;\
  52                     } else {\
  53                         i++;\
  54                         pos_begin = pos_end + 1;\
  55                     }\
  56                 }\
  57                 if( labelstring[pos_end] == '\0' )\
  58                     break;\
  59             }\
  60             DAI_THROWE(UNKNOWN_ENUM_VALUE,"'" + std::string(w) + "' is not in [" + std::string(labelstring) + "]");\
  61         }\
  62 \
  63         operator value() const { return v; }\
  64 \
  65         operator size_t() const { return (size_t)v; }\
  66 \
  67         operator char const*() const {\
  68             static char labelstring[] = #val0 "," #__VA_ARGS__;\
  69             size_t pos_begin = 0;\
  70             size_t i = 0;\
  71             for( size_t pos_end = 0; ; pos_end++ )\
  72                 if( (labelstring[pos_end] == ',') || (labelstring[pos_end] == '\0') ) {\
  73                     if( (size_t)v == i ) {\
  74                         labelstring[pos_end] = '\0';\
  75                         return labelstring + pos_begin;\
  76                     } else {\
  77                         i++;\
  78                         pos_begin = pos_end + 1;\
  79                     }\
  80                 }\
  81         }\
  82 \
  83         operator wchar_t const*() const {\
  84             static wchar_t labelstring[] = #val0 L"," #__VA_ARGS__;\
  85             size_t pos_begin = 0;\
  86             size_t i = 0;\
  87             for( size_t pos_end = 0; ; pos_end++ )\
  88                 if( (labelstring[pos_end] == L',') || (labelstring[pos_end] == L'\0') ) {\
  89                     if( (size_t)v == i ) {\
  90                         labelstring[pos_end] = L'\0';\
  91                         return labelstring + pos_begin;\
  92                     } else {\
  93                         i++;\
  94                         pos_begin = pos_end + 1;\
  95                     }\
  96                 }\
  97         }\
  98 \
  99         friend std::istream& operator >> (std::istream& is, x& y) {\
 100             std::string s;\
 101             is >> s;\
 102             y = x(s.c_str());\
 103             return is;\
 104         }\
 105 \
 106         friend std::wistream& operator >> (std::wistream& wis, x& y) {\
 107             std::wstring s;\
 108             wis >> s;\
 109             y = x((const char *)s.c_str());\
 110             return wis;\
 111         }\
 112 \
 113         friend std::ostream& operator << (std::ostream& os, const x& y) {\
 114             os << (const char *)y;\
 115             return os;\
 116         }\
 117 \
 118         friend std::wostream& operator << (std::wostream& wos, const x& y) {\
 119             wos << (const wchar_t *)y;\
 120             return wos;\
 121         }\
 122 \
 123     protected:\
 124         value v;\
 125 };
 126
 127
 128 #endif