contrib/src/applet/prepifelse.cpp

   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:  This file is the implementation of the Preprocessor object
  26 *               for parsing the <!--#if directive
  27 *
  28 ****************************************************************************/
  29
  30 // For compilers that support precompilation
  31 #include "wx/wxprec.h"
  32 #include "wx/html/forcelnk.h"
  33
  34 // Include private headers
  35 #include "wx/applet/prepifelse.h"
  36 #include "wx/applet/ifelsevar.h"
  37
  38 /*---------------------------- Global variables ---------------------------*/
  39
  40
  41 /*----------------------------- Implementation ----------------------------*/
  42
  43 /* {SECRET} */
  44 /****************************************************************************
  45 REMARKS:
  46 None of the Reverse Find functions in wxWindows appear to work in a way that
  47 can be used by our code. This includes the libstr rfind implementations which
  48 do not correctly pass the given return value.
  49 ****************************************************************************/
  50 int ReverseFind(
  51     const wxString &tstr,
  52     const wxString &str)
  53 {
  54     wxASSERT( str.GetStringData()->IsValid() );
  55
  56     // TODO could be made much quicker than that
  57     int p = tstr.Len()-str.Len()-1;
  58     while ( p >= 0 ) {
  59         if ( wxStrncmp(tstr.c_str() + p, str.c_str(), str.Len()) == 0 )
  60             return p;
  61         p--;
  62         }
  63
  64     return -1;
  65 }
  66
  67 /****************************************************************************
  68 PARAMETERS:
  69 text        - HTML to process for if/else blocks
  70
  71 RETURNS:
  72 The string containing the processed HTML
  73
  74 REMARKS:
  75 This function replaces #if, #else, and #endif directives with the text
  76 contained within the blocks, dependant on the value of the given boolean
  77 variable. The variable is created by making a sub class of wxIfElseVariable.
  78 Dynamic class construction is used at run time internally to create an instance
  79 of this class and access the value of the variable.
  80
  81 SEE ALSO:
  82 wxIfElseVariable
  83 ****************************************************************************/
  84 wxString wxIfElsePrep::Process(
  85     const wxString& text) const
  86 {
  87         int b;
  88         char ft[] = "<!--#if ";
  89
  90         // make a copy so we can replace text as we go without affecting the original
  91         wxString output = text;
  92     while ((b = ReverseFind(output.Lower(), ft)) != -1) {
  93                 // Loop until every #echo directive is found
  94                 // We search from the end of the string so that #if statements will properly recurse
  95                 // and we avoid the hassle of matching statements with the correct <!--#endif-->
  96                 int end, c, n;
  97         wxString usecode, code;
  98         wxString cname;
  99         wxString tag;
 100         bool value;
 101
 102         code = wxString("");
 103
 104         // grab the tag and get the name of the variable
 105         end = (output.Mid(b)).Find("-->");
 106         if (end == -1) {
 107 #ifdef CHECKED
 108             wxMessageBox("wxHTML #if error: Premature end of file while parsing #if.","Error",wxICON_ERROR);
 109 #endif
 110             break;
 111                         }
 112
 113         end += 3;
 114         tag = output.Mid(b, end);
 115         output.Remove(b, end);
 116
 117         c = tag.Find("-->");
 118         n = c;
 119
 120         // find the classname
 121         c = (tag.Mid(8, n-8)).Find(" ");
 122             if (c == -1) n -= 8;
 123         else n = c;
 124         cname = tag.Mid(8, n);
 125
 126         cname.Trim(false);
 127         c = cname.Find("\"");
 128         if (c != -1) cname = cname.Mid(c+1);
 129         c = cname.Find("\"");
 130             if (c != -1) cname = cname.Mid(0, c);
 131
 132         // Grab the value from the variable class identified by cname
 133         value = wxIfElseVariable::GetValue(cname);
 134
 135         // Find the end of the tag (<!--#endif-->) and copy it all into the variable code
 136         end = ((output.Mid(b)).Lower()).Find("<!--#endif-->");
 137         if (end == -1) {
 138 #ifdef CHECKED
 139             wxMessageBox("wxHTML #if error: Premature end of file while searching for matching #endif.","Error",wxICON_ERROR);
 140 #endif
 141             break;
 142                         }
 143
 144         code = output.Mid(b, end);
 145         output.Remove(b, end+13); // remove the entire #if block from original document
 146
 147         // Find out if there is an else statement
 148         end = (code.Lower()).Find("<!--#else-->");
 149         if (end != -1) {
 150             if (!value) {
 151                 // Use the else statement
 152                 usecode = code.Mid(end+12);
 153                 }
 154             else {
 155                 // Use statement before #else
 156                 usecode = code.Mid(0, end);
 157                 }
 158             }
 159         else if (value) {
 160             // There is no #else statement
 161             usecode = code;
 162             }
 163
 164         if (usecode != wxString(""))
 165             output = (output.Mid(0,b) + usecode + output.Mid(b));
 166                 }
 167
 168     return output;
 169 }
 170
 171 FORCE_LINK(ifelsevar)