X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/639e001d875797ec81217f6a9b8cd93285b02e80..e225fe17a8dc6a209d224cc966463644c6cc466f:/src/common/string.cpp

diff --git a/src/common/string.cpp b/src/common/string.cpp
index 98a635bc49..c2bab603e2 100644
--- a/src/common/string.cpp
+++ b/src/common/string.cpp
@@ -174,8 +174,16 @@ void wxStringBase::InitWith(const wxChar *psz, size_t nPos, size_t nLength)
 // poor man's iterators are "void *" pointers
 wxStringBase::wxStringBase(const void *pStart, const void *pEnd)
 {
-  InitWith((const wxChar *)pStart, 0,
-           (const wxChar *)pEnd - (const wxChar *)pStart);
+  if ( pEnd >= pStart )
+  {
+    InitWith((const wxChar *)pStart, 0,
+             (const wxChar *)pEnd - (const wxChar *)pStart);
+  }
+  else
+  {
+    wxFAIL_MSG( _T("pStart is not before pEnd") );
+    Init();
+  }
 }
 
 wxStringBase::wxStringBase(size_type n, wxChar ch)
@@ -434,36 +442,47 @@ void wxStringBase::swap(wxStringBase& str)
 
 size_t wxStringBase::find(const wxStringBase& str, size_t nStart) const
 {
+    // deal with the special case of empty string first
+    const size_t nLen = length();
+    const size_t nLenOther = str.length();
+
+    if ( !nLenOther )
+    {
+        // empty string is a substring of anything
+        return 0;
+    }
+
+    if ( !nLen )
+    {
+        // the other string is non empty so can't be our substring
+        return npos;
+    }
+
     wxASSERT( str.GetStringData()->IsValid() );
-    wxASSERT( nStart <= length() );
+    wxASSERT( nStart <= nLen );
+
+    const wxChar * const other = str.c_str();
 
-    //anchor
+    // anchor
     const wxChar* p = (const wxChar*)wxTmemchr(c_str() + nStart,
-                                               str.c_str()[0],
-                                               length() - nStart);
+                                               *other,
+                                               nLen - nStart);
 
-    if(!p)
+    if ( !p )
         return npos;
 
-    while(p - c_str() + str.length() <= length() &&
-          wxTmemcmp(p, str.c_str(), str.length()) )
+    while ( p - c_str() + nLenOther <= nLen && wxTmemcmp(p, other, nLenOther) )
     {
-        //Previosly passed as the first argument to wxTmemchr,
-        //but C/C++ standard does not specify evaluation order
-        //of arguments to functions -
-        //http://embedded.com/showArticle.jhtml?articleID=9900607
-        ++p;
-
-        //anchor again
-        p = (const wxChar*)wxTmemchr(p,
-                                     str.c_str()[0],
-                                     length() - (p - c_str()));
-
-        if(!p)
+        p++;
+
+        // anchor again
+        p = (const wxChar*)wxTmemchr(p, *other, nLen - (p - c_str()));
+
+        if ( !p )
             return npos;
     }
 
-    return (p - c_str() + str.length() <= length()) ? p - c_str() : npos;
+    return p - c_str() + nLenOther <= nLen ? p - c_str() : npos;
 }
 
 size_t wxStringBase::find(const wxChar* sz, size_t nStart, size_t n) const