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C/C++ Source or Header  |  2002-02-08  |  5KB  |  136 lines
  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.  
  136.