contrib/include/wx/applet/ifelsevar.h

   1 /****************************************************************************
   2 *
   3 *                       wxWindows HTML Applet Package
   4 *
   5 *               Copyright (C) 1991-2001 SciTech Software, Inc.
   6 *                            All rights reserved.
   7 *
   8 *  ========================================================================
   9 *
  10 *    The contents of this file are subject to the wxWindows License
  11 *    Version 3.0 (the "License"); you may not use this file except in
  12 *    compliance with the License. You may obtain a copy of the License at
  13 *    http://www.wxwindows.org/licence3.txt
  14 *
  15 *    Software distributed under the License is distributed on an
  16 *    "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  17 *    implied. See the License for the specific language governing
  18 *    rights and limitations under the License.
  19 *
  20 *  ========================================================================
  21 *
  22 * Language:             ANSI C++
  23 * Environment:  Any
  24 *
  25 * Description:  Header file for wxIfElseVariable Class, Dynamically constructed
  26 * objects representing variables in SSI #if, #else and #endif directives
  27 *
  28 ****************************************************************************/
  29
  30 #ifndef __WX_IFELSEVAR_H
  31 #define __WX_IFELSEVAR_H
  32
  33 #include "wx/object.h"
  34 #include "wx/hash.h"
  35
  36 /*--------------------------- Class Definitions ---------------------------*/
  37
  38 /****************************************************************************
  39 RETURNS:
  40 The boolean value of the variable
  41
  42 REMARKS:
  43 To create new variables for the #if, #else and #endif HTML preprocessing
  44 blocks you need to derive classes from wxIfElseVariable and override the
  45 pure virtual GetValue function. However this should not be done directly
  46 but by using the BEGIN_IFELSE_VARIABLE and END_IFELSE_VARIABLE macros
  47
  48 SEE ALSO:
  49 wxIfElsePrep, BEGIN_IFELSE_VARIABLE, END_IFELSE_VARIABLE
  50 ****************************************************************************/
  51 typedef bool (*wxIfElseVariableGetValueFn)();
  52
  53 /****************************************************************************
  54 REMARKS:
  55 wxIfElseVariable class Definition
  56 ****************************************************************************/
  57 class wxIfElseVariable : public wxObject {
  58 protected:
  59     const wxChar                *m_varName;
  60     wxIfElseVariableGetValueFn  m_getValueFn;
  61     static wxIfElseVariable     *sm_first;
  62     wxIfElseVariable            *m_next;
  63     static wxHashTable          *sm_varTable;
  64     bool                        forced;
  65     bool                        forceVal;
  66
  67     static inline wxIfElseVariable *wxIfElseVariable::FindVariable(const wxChar *varName);
  68
  69 public:
  70     // Constructor to create the echo variable and register the class
  71     wxIfElseVariable(
  72         const char *varName,
  73         wxIfElseVariableGetValueFn getValueFn);
  74
  75     // Member variable access functions
  76     const wxChar *GetClassName() const            { return m_varName; }
  77     wxIfElseVariableGetValueFn GetValueFn() const { return m_getValueFn; }
  78     static const wxIfElseVariable* GetFirst()     { return sm_first; }
  79     const wxIfElseVariable* GetNext() const       { return m_next; }
  80
  81     // Static functions to retrieve any variable avaliable
  82     static bool GetValue(const wxChar *varName);
  83     static bool Exists(const wxChar *varName);
  84     static void Force(const wxChar *varName, bool val);
  85
  86     // Initializes parent pointers and hash table for fast searching.
  87     static void Initialize();
  88
  89     // Cleans up hash table used for fast searching.
  90     static void CleanUp();
  91     };
  92
  93 /****************************************************************************
  94 PARAMETERS:
  95 class   - Name of class for echo variable to find
  96
  97 RETURNS:
  98 Pointer to the echo variable class
  99
 100 REMARKS:
 101 Inline helper function to find the echo variable from it's class name.
 102 ****************************************************************************/
 103 inline wxIfElseVariable *wxIfElseVariable::FindVariable(
 104     const wxChar *varName)
 105 {
 106     if (sm_varTable)
 107         return (wxIfElseVariable*)sm_varTable->Get(varName);
 108     else {
 109         wxIfElseVariable *info = sm_first;
 110         while (info) {
 111             if (info->m_varName && wxStrcmp(info->m_varName, varName) == 0)
 112                 return info;
 113             info = info->m_next;
 114             }
 115         return NULL;
 116         }
 117 }
 118
 119 /*--------------------------------- MACROS --------------------------------*/
 120
 121 #define BEGIN_IFELSE_VARIABLE(name)                                         \
 122 bool wxIfElseVariableFn##name();                                            \
 123 wxIfElseVariable wxIfElseVariable##name(#name,wxIfElseVariableFn##name);    \
 124 bool wxIfElseVariableFn##name() {                                           \
 125
 126 #define END_IFELSE_VARIABLE(returnval)                                      \
 127     return returnval;                                                       \
 128     }
 129
 130 #define IFELSE_VARIABLE(name, state)                                        \
 131     BEGIN_IFELSE_VARIABLE(##name##);                                        \
 132     END_IFELSE_VARIABLE(bool (state))
 133
 134 #endif // __WX_IFELSEVAR_H
 135