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         char ftnot[] = "<!--#if NOT ";
  90     char ftnot2[] = "<!--#if !";
  91
  92
  93         // make a copy so we can replace text as we go without affecting the original
  94         wxString output = text;
  95     while ((b = ReverseFind(output.Lower(), ft)) != -1) {
  96                 // Loop until every #if directive is found
  97                 // We search from the end of the string so that #if statements will properly recurse
  98                 // and we avoid the hassle of matching statements with the correct <!--#endif-->
  99         bool notval = false;
 100         int off = 0;
 101         int end, c, n;
 102         wxString usecode, code;
 103         wxString cname;
 104         wxString tag;
 105         bool value;
 106
 107         code = wxString("");
 108
 109         if (output.Mid(b, strlen(ftnot) ).CmpNoCase(ftnot) == 0 ) {
 110             notval = true;
 111             off = 4;
 112             }
 113         else if (output.Mid(b, strlen(ftnot2) ).CmpNoCase(ftnot2) == 0 ) {
 114             notval = true;
 115             off = 1;
 116             }
 117
 118         // grab the tag and get the name of the variable
 119         end = (output.Mid(b)).Find("-->");
 120         if (end == -1) {
 121 #ifdef CHECKED
 122             wxMessageBox("wxHTML #if error: Premature end of file while parsing #if.","Error",wxICON_ERROR);
 123 #endif
 124             break;
 125                         }
 126
 127         end += 3;
 128         tag = output.Mid(b, end);
 129         output.Remove(b, end);
 130
 131         c = tag.Find("-->");
 132         n = c;
 133
 134         // find the classname
 135         c = (tag.Mid(8+off, n-(8+off))).Find(" ");
 136             if (c == -1) n -= (8+off);
 137         else n = c;
 138         cname = tag.Mid(8+off, n);
 139
 140         cname.Trim(false);
 141         c = cname.Find("\"");
 142         if (c != -1) cname = cname.Mid(c+1);
 143         c = cname.Find("\"");
 144             if (c != -1) cname = cname.Mid(0, c);
 145
 146         // Grab the value from the variable class identified by cname
 147         value = wxIfElseVariable::FindValue(cname);
 148         if (notval) value = !value;
 149
 150         // Find the end of the tag (<!--#endif-->) and copy it all into the variable code
 151         end = ((output.Mid(b)).Lower()).Find("<!--#endif-->");
 152         if (end == -1) {
 153 #ifdef CHECKED
 154             wxMessageBox("wxHTML #if error: Premature end of file while searching for matching #endif.","Error",wxICON_ERROR);
 155 #endif
 156             break;
 157                         }
 158
 159         code = output.Mid(b, end);
 160         output.Remove(b, end+13); // remove the entire #if block from original document
 161
 162         // Find out if there is an else statement
 163         end = (code.Lower()).Find("<!--#else-->");
 164         if (end != -1) {
 165             if (!value) {
 166                 // Use the else statement
 167                 usecode = code.Mid(end+12);
 168                 }
 169             else {
 170                 // Use statement before #else
 171                 usecode = code.Mid(0, end);
 172                 }
 173             }
 174         else if (value) {
 175             // There is no #else statement
 176             usecode = code;
 177             }
 178
 179         if (usecode != wxString(""))
 180             output = (output.Mid(0,b) + usecode + output.Mid(b));
 181                 }
 182
 183     return output;
 184 }
 185
 186 FORCE_LINK(ifelsevar)