Clarified wxPropertyGrid::HitTest() docs

[wxWidgets.git] / include / wx / string.h

diff --git a/include/wx/string.h b/include/wx/string.h
index b72a312f45576726cbbeac7e8c1c24b99a3a3a27..b6cb7836b331bc57bfc9fa3268d5fd162b3fd767 100644 (file)
--- a/include/wx/string.h
+++ b/include/wx/string.h
@@ -57,6 +57,38 @@
 #include "wx/stringops.h"
 #include "wx/unichar.h"
 
 #include "wx/stringops.h"
 #include "wx/unichar.h"
 

+// by default we cache the mapping of the positions in UTF-8 string to the byte
+// offset as this results in noticeable performance improvements for loops over
+// strings using indices; comment out this line to disable this
+//
+// notice that this optimization is well worth using even in debug builds as it
+// changes asymptotic complexity of algorithms using indices to iterate over
+// wxString back to expected linear from quadratic
+//
+// also notice that wxTLS_TYPE() (__declspec(thread) in this case) is unsafe to
+// use in DLL build under pre-Vista Windows so we disable this code for now, if
+// anybody really needs to use UTF-8 build under Windows with this optimization
+// it would have to be re-tested and probably corrected
+// CS: under OSX release builds the string destructor/cache cleanup sometimes
+// crashes, disable until we find the true reason or a better workaround
+#if wxUSE_UNICODE_UTF8 && !defined(__WXMSW__) && !defined(__WXOSX__)
+    #define wxUSE_STRING_POS_CACHE 1
+#else
+    #define wxUSE_STRING_POS_CACHE 0
+#endif
+
+#if wxUSE_STRING_POS_CACHE
+    #include "wx/tls.h"
+
+    // change this 0 to 1 to enable additional (very expensive) asserts
+    // verifying that string caching logic works as expected
+    #if 0
+        #define wxSTRING_CACHE_ASSERT(cond) wxASSERT(cond)
+    #else
+        #define wxSTRING_CACHE_ASSERT(cond)
+    #endif
+#endif // wxUSE_STRING_POS_CACHE
+

 class WXDLLIMPEXP_FWD_BASE wxString;
 
 // unless this symbol is predefined to disable the compatibility functions, do
 class WXDLLIMPEXP_FWD_BASE wxString;
 
 // unless this symbol is predefined to disable the compatibility functions, do


@@ -394,7 +426,7 @@ private:
 
     // the node belongs to a particular iterator instance, it's not copied
     // when a copy of the iterator is made
 
     // the node belongs to a particular iterator instance, it's not copied
     // when a copy of the iterator is made

-    DECLARE_NO_COPY_CLASS(wxStringIteratorNode)
+    wxDECLARE_NO_COPY_CLASS(wxStringIteratorNode);

 };
 #endif // wxUSE_UNICODE_UTF8
 
 };
 #endif // wxUSE_UNICODE_UTF8
 


@@ -508,10 +540,13 @@ private:
   static size_t LenToImpl(size_t len) { return len; }
   static size_t PosFromImpl(size_t pos) { return pos; }
 
   static size_t LenToImpl(size_t len) { return len; }
   static size_t PosFromImpl(size_t pos) { return pos; }
 

-  // we don't want to define this as an empty inline function as it could
+  // we don't want to define these as empty inline functions as it could

   // result in noticeable (and quite unnecessary in non-UTF-8 build) slowdown
   // in debug build where the inline functions are not effectively inlined
   // result in noticeable (and quite unnecessary in non-UTF-8 build) slowdown
   // in debug build where the inline functions are not effectively inlined

-  #define wxSTRING_INVALIDATE_INDEX_CACHE()
+  #define wxSTRING_INVALIDATE_CACHE()
+  #define wxSTRING_INVALIDATE_CACHED_LENGTH()
+  #define wxSTRING_UPDATE_CACHED_LENGTH(n)
+  #define wxSTRING_SET_CACHED_LENGTH(n)

 
 #else // wxUSE_UNICODE_UTF8
 
 
 #else // wxUSE_UNICODE_UTF8
 


@@ -527,62 +562,274 @@ private:
   static SubstrBufFromWC ImplStr(const wchar_t* str, size_t n)
     { return ConvertStr(str, n, wxMBConvUTF8()); }
 
   static SubstrBufFromWC ImplStr(const wchar_t* str, size_t n)
     { return ConvertStr(str, n, wxMBConvUTF8()); }
 

-  // this is an extremely simple cache used by PosToImpl()
-  struct PosToImplCache
+#if wxUSE_STRING_POS_CACHE
+  // this is an extremely simple cache used by PosToImpl(): each cache element
+  // contains the string it applies to and the index corresponding to the last
+  // used position in this wxString in its m_impl string
+  //
+  // NB: notice that this struct (and nested Element one) must be a POD or we
+  //     wouldn't be able to use a thread-local variable of this type, in
+  //     particular it should have no ctor -- we rely on statics being
+  //     initialized to 0 instead
+  struct Cache

   {
   {

-      const wxString *str;
-      size_t pos,
-             impl;
+      enum { SIZE = 8 };
+
+      struct Element
+      {
+          const wxString *str;  // the string to which this element applies
+          size_t pos,           // the cached index in this string
+                 impl,          // the corresponding position in its m_impl
+                 len;           // cached length or npos if unknown
+
+          // reset cached index to 0
+          void ResetPos() { pos = impl = 0; }
+
+          // reset position and length
+          void Reset() { ResetPos(); len = npos; }
+      };
+
+      // cache the indices mapping for the last few string used
+      Element cached[SIZE];
+
+      // the last used index
+      unsigned lastUsed;

   };
 
   };
 

-  static PosToImplCache ms_cache;
+#ifndef wxHAS_COMPILER_TLS
+  // we must use an accessor function and not a static variable when the TLS
+  // variables support is implemented in the library (and not by the compiler)
+  // because the global s_cache variable could be not yet initialized when a
+  // ctor of another global object is executed and if that ctor uses any
+  // wxString methods, bad things happen
+  //
+  // however notice that this approach does not work when compiler TLS is used,
+  // at least not with g++ 4.1.2 under amd64 as it apparently compiles code
+  // using this accessor incorrectly when optimizations are enabled (-O2 is
+  // enough) -- luckily we don't need it then neither as static __thread
+  // variables are initialized by 0 anyhow then and so we can use the variable
+  // directly
+  WXEXPORT static Cache& GetCache()
+  {
+      static wxTLS_TYPE(Cache) s_cache;

 
 

-  size_t PosToImpl(size_t pos) const
+      return wxTLS_VALUE(s_cache);
+  }
+
+  // this helper struct is used to ensure that GetCache() is called during
+  // static initialization time, i.e. before any threads creation, as otherwise
+  // the static s_cache construction inside GetCache() wouldn't be MT-safe
+  friend struct wxStrCacheInitializer;
+#else // wxHAS_COMPILER_TLS
+  static wxTLS_TYPE(Cache) ms_cache;
+  static Cache& GetCache() { return wxTLS_VALUE(ms_cache); }
+#endif // !wxHAS_COMPILER_TLS/wxHAS_COMPILER_TLS
+
+  static Cache::Element *GetCacheBegin() { return GetCache().cached; }
+  static Cache::Element *GetCacheEnd() { return GetCacheBegin() + Cache::SIZE; }
+  static unsigned& LastUsedCacheElement() { return GetCache().lastUsed; }
+
+  // this is used in debug builds only to provide a convenient function,
+  // callable from a debugger, to show the cache contents
+  friend struct wxStrCacheDumper;
+
+  // uncomment this to have access to some profiling statistics on program
+  // termination
+  //#define wxPROFILE_STRING_CACHE
+
+#ifdef wxPROFILE_STRING_CACHE
+  static struct PosToImplCacheStats

   {
   {

-      if ( pos == 0 || pos == npos )
-          return pos;
+      unsigned postot,  // total non-trivial calls to PosToImpl
+               poshits, // cache hits from PosToImpl()
+               mishits, // cached position beyond the needed one
+               sumpos,  // sum of all positions, used to compute the
+                        // average position after dividing by postot
+               sumofs,  // sum of all offsets after using the cache, used to
+                        // compute the average after dividing by hits
+               lentot,  // number of total calls to length()
+               lenhits; // number of cache hits in length()
+  } ms_cacheStats;
+
+  friend struct wxStrCacheStatsDumper;
+
+  #define wxCACHE_PROFILE_FIELD_INC(field) ms_cacheStats.field++
+  #define wxCACHE_PROFILE_FIELD_ADD(field, val) ms_cacheStats.field += (val)
+#else // !wxPROFILE_STRING_CACHE
+  #define wxCACHE_PROFILE_FIELD_INC(field)
+  #define wxCACHE_PROFILE_FIELD_ADD(field, val)
+#endif // wxPROFILE_STRING_CACHE/!wxPROFILE_STRING_CACHE
+
+  // note: it could seem that the functions below shouldn't be inline because
+  // they are big, contain loops and so the compiler shouldn't be able to
+  // inline them anyhow, however moving them into string.cpp does decrease the
+  // code performance by ~5%, at least when using g++ 4.1 so do keep them here
+  // unless tests show that it's not advantageous any more
+
+  // return the pointer to the cache element for this string or NULL if not
+  // cached
+  Cache::Element *FindCacheElement() const
+  {
+      // profiling seems to show a small but consistent gain if we use this
+      // simple loop instead of starting from the last used element (there are
+      // a lot of misses in this function...)
+      Cache::Element * const cacheBegin = GetCacheBegin();
+#ifndef wxHAS_COMPILER_TLS
+      // during destruction tls calls may return NULL, in this case return NULL
+      // immediately without accessing anything else
+      if ( cacheBegin == NULL )
+        return NULL;
+#endif
+      Cache::Element * const cacheEnd = GetCacheEnd();
+      for ( Cache::Element *c = cacheBegin; c != cacheEnd; c++ )
+      {
+          if ( c->str == this )
+              return c;
+      }
+
+      return NULL;
+  }

 
 

-      PosToImplCache& cache = ms_cache;
-      if ( this == cache.str )
+  // unlike FindCacheElement(), this one always returns a valid pointer to the
+  // cache element for this string, it may have valid last cached position and
+  // its corresponding index in the byte string or not
+  Cache::Element *GetCacheElement() const
+  {
+      Cache::Element * const cacheBegin = GetCacheBegin();
+      Cache::Element * const cacheEnd = GetCacheEnd();
+      Cache::Element * const cacheStart = cacheBegin + LastUsedCacheElement();
+
+      // check the last used first, this does no (measurable) harm for a miss
+      // but does help for simple loops addressing the same string all the time
+      if ( cacheStart->str == this )
+          return cacheStart;
+
+      // notice that we're going to check cacheStart again inside this call but
+      // profiling shows that it's still faster to use a simple loop like
+      // inside FindCacheElement() than manually looping with wrapping starting
+      // from the cache entry after the start one
+      Cache::Element *c = FindCacheElement();
+      if ( !c )

       {
       {

-          if ( pos == cache.pos )
-              return cache.impl;
+          // claim the next cache entry for this string
+          c = cacheStart;
+          if ( ++c == cacheEnd )
+              c = cacheBegin;

 
 

-          // TODO: is it worth complicating this function even further by going
-          //       backwards from the last position? it might be if we're just
-          //       before it...
-          if ( cache.pos > pos )
-          {
-              cache.pos =
-              cache.impl = 0;
-          }
+          c->str = this;
+          c->Reset();
+
+          // and remember the last used element
+          LastUsedCacheElement() = c - cacheBegin;

       }
       }

-      else // data for this string not cached
+
+      return c;
+  }
+
+  size_t DoPosToImpl(size_t pos) const
+  {
+      wxCACHE_PROFILE_FIELD_INC(postot);
+
+      // NB: although the case of pos == 1 (and offset from cached position
+      //     equal to 1) are common, nothing is gained by writing special code
+      //     for handling them, the compiler (at least g++ 4.1 used) seems to
+      //     optimize the code well enough on its own
+
+      wxCACHE_PROFILE_FIELD_ADD(sumpos, pos);
+
+      Cache::Element * const cache = GetCacheElement();
+
+      // cached position can't be 0 so if it is, it means that this entry was
+      // used for length caching only so far, i.e. it doesn't count as a hit
+      // from our point of view
+      if ( cache->pos )

       {
       {

-          cache.str = this;
-          cache.pos =
-          cache.impl = 0;
+          wxCACHE_PROFILE_FIELD_INC(poshits);

       }
 
       }
 

-      wxStringImpl::const_iterator i(m_impl.begin() + cache.impl);
-      for ( size_t n = cache.pos; n < pos; n++ )
+      if ( pos == cache->pos )
+          return cache->impl;
+
+      // this seems to happen only rarely so just reset the cache in this case
+      // instead of complicating code even further by seeking backwards in this
+      // case
+      if ( cache->pos > pos )
+      {
+          wxCACHE_PROFILE_FIELD_INC(mishits);
+
+          cache->ResetPos();
+      }
+
+      wxCACHE_PROFILE_FIELD_ADD(sumofs, pos - cache->pos);
+
+
+      wxStringImpl::const_iterator i(m_impl.begin() + cache->impl);
+      for ( size_t n = cache->pos; n < pos; n++ )

           wxStringOperations::IncIter(i);
 
           wxStringOperations::IncIter(i);
 

-      cache.pos = pos;
-      return cache.impl = i - m_impl.begin();
+      cache->pos = pos;
+      cache->impl = i - m_impl.begin();
+
+      wxSTRING_CACHE_ASSERT(
+          (int)cache->impl == (begin() + pos).impl() - m_impl.begin() );
+
+      return cache->impl;
+  }
+
+  void InvalidateCache()
+  {
+      Cache::Element * const cache = FindCacheElement();
+      if ( cache )
+          cache->Reset();
+  }
+
+  void InvalidateCachedLength()
+  {
+      Cache::Element * const cache = FindCacheElement();
+      if ( cache )
+          cache->len = npos;
+  }
+
+  void SetCachedLength(size_t len)
+  {
+      // we optimistically cache the length here even if the string wasn't
+      // present in the cache before, this seems to do no harm and the
+      // potential for avoiding length recomputation for long strings looks
+      // interesting
+      GetCacheElement()->len = len;

   }
 
   }
 

-  void InvalidatePosToImplCache()
+  void UpdateCachedLength(ptrdiff_t delta)

   {
   {

-      PosToImplCache& cache = ms_cache;
-      if ( cache.str == this )
+      Cache::Element * const cache = FindCacheElement();
+      if ( cache && cache->len != npos )

       {
       {

-          cache.pos =
-              cache.impl = 0;
+          wxSTRING_CACHE_ASSERT( (ptrdiff_t)cache->len + delta >= 0 );
+
+          cache->len += delta;

       }
   }
 
       }
   }
 

-  #define wxSTRING_INVALIDATE_INDEX_CACHE() InvalidatePosToImplCache()
+  #define wxSTRING_INVALIDATE_CACHE() InvalidateCache()
+  #define wxSTRING_INVALIDATE_CACHED_LENGTH() InvalidateCachedLength()
+  #define wxSTRING_UPDATE_CACHED_LENGTH(n) UpdateCachedLength(n)
+  #define wxSTRING_SET_CACHED_LENGTH(n) SetCachedLength(n)
+#else // !wxUSE_STRING_POS_CACHE
+  size_t DoPosToImpl(size_t pos) const
+  {
+      return (begin() + pos).impl() - m_impl.begin();
+  }
+
+  #define wxSTRING_INVALIDATE_CACHE()
+  #define wxSTRING_INVALIDATE_CACHED_LENGTH()
+  #define wxSTRING_UPDATE_CACHED_LENGTH(n)
+  #define wxSTRING_SET_CACHED_LENGTH(n)
+#endif // wxUSE_STRING_POS_CACHE/!wxUSE_STRING_POS_CACHE
+
+  size_t PosToImpl(size_t pos) const
+  {
+      return pos == 0 || pos == npos ? pos : DoPosToImpl(pos);
+  }

 
   void PosLenToImpl(size_t pos, size_t len, size_t *implPos, size_t *implLen) const;
 
 
   void PosLenToImpl(size_t pos, size_t len, size_t *implPos, size_t *implLen) const;
 


@@ -613,22 +860,26 @@ public:
   typedef size_t size_type;
   typedef wxUniChar const_reference;
 
   typedef size_t size_type;
   typedef wxUniChar const_reference;
 

-#if wxUSE_STL
+#if wxUSE_STD_STRING

   #if wxUSE_UNICODE_UTF8
     // random access is not O(1), as required by Random Access Iterator
     #define WX_STR_ITERATOR_TAG std::bidirectional_iterator_tag
   #else
     #define WX_STR_ITERATOR_TAG std::random_access_iterator_tag
   #endif
   #if wxUSE_UNICODE_UTF8
     // random access is not O(1), as required by Random Access Iterator
     #define WX_STR_ITERATOR_TAG std::bidirectional_iterator_tag
   #else
     #define WX_STR_ITERATOR_TAG std::random_access_iterator_tag
   #endif

+  #define WX_DEFINE_ITERATOR_CATEGORY(cat) typedef cat iterator_category;

 #else
 #else

-  #define WX_STR_ITERATOR_TAG void /* dummy type */
+  // not defining iterator_category at all in this case is better than defining
+  // it as some dummy type -- at least it results in more intelligible error
+  // messages
+  #define WX_DEFINE_ITERATOR_CATEGORY(cat)

 #endif
 
   #define WX_STR_ITERATOR_IMPL(iterator_name, pointer_type, reference_type) \
       private:                                                              \
           typedef wxStringImpl::iterator_name underlying_iterator;          \
       public:                                                               \
 #endif
 
   #define WX_STR_ITERATOR_IMPL(iterator_name, pointer_type, reference_type) \
       private:                                                              \
           typedef wxStringImpl::iterator_name underlying_iterator;          \
       public:                                                               \

-          typedef WX_STR_ITERATOR_TAG iterator_category;                    \
+          WX_DEFINE_ITERATOR_CATEGORY(WX_STR_ITERATOR_TAG)                  \

           typedef wxUniChar value_type;                                     \
           typedef int difference_type;                                      \
           typedef reference_type reference;                                 \
           typedef wxUniChar value_type;                                     \
           typedef int difference_type;                                      \
           typedef reference_type reference;                                 \


@@ -727,7 +978,7 @@ public:
       }
 
       reference operator*()
       }
 
       reference operator*()

-        { return wxUniCharRef::CreateForString(m_node, m_cur); }
+        { return wxUniCharRef::CreateForString(*str(), m_cur); }

 
       iterator operator+(ptrdiff_t n) const
         { return iterator(str(), wxStringOperations::AddToIter(m_cur, n)); }
 
       iterator operator+(ptrdiff_t n) const
         { return iterator(str(), wxStringOperations::AddToIter(m_cur, n)); }


@@ -738,7 +989,7 @@ public:
       iterator(wxString *str, underlying_iterator ptr)
           : m_cur(ptr), m_node(str, &m_cur) {}
 
       iterator(wxString *str, underlying_iterator ptr)
           : m_cur(ptr), m_node(str, &m_cur) {}
 

-      wxString* str() const { return wx_const_cast(wxString*, m_node.m_str); }
+      wxString* str() const { return const_cast<wxString*>(m_node.m_str); }

 
       wxStringIteratorNode m_node;
 
 
       wxStringIteratorNode m_node;
 


@@ -791,9 +1042,9 @@ public:
   size_t IterToImplPos(wxString::iterator i) const
     { return wxStringImpl::const_iterator(i.impl()) - m_impl.begin(); }
 
   size_t IterToImplPos(wxString::iterator i) const
     { return wxStringImpl::const_iterator(i.impl()) - m_impl.begin(); }
 

-  iterator GetNthIter(size_t n)
+  iterator GetIterForNthChar(size_t n)

     { return iterator(this, m_impl.begin() + PosToImpl(n)); }
     { return iterator(this, m_impl.begin() + PosToImpl(n)); }

-  const_iterator GetNthIter(size_t n) const
+  const_iterator GetIterForNthChar(size_t n) const

     { return const_iterator(this, m_impl.begin() + PosToImpl(n)); }
 #else // !wxUSE_UNICODE_UTF8
 
     { return const_iterator(this, m_impl.begin() + PosToImpl(n)); }
 #else // !wxUSE_UNICODE_UTF8
 


@@ -847,8 +1098,8 @@ public:
           : m_cur(ptr) {}
   };
 
           : m_cur(ptr) {}
   };
 

-  iterator GetNthIter(size_t n) { return begin() + n; }
-  const_iterator GetNthIter(size_t n) const { return begin() + n; }
+  iterator GetIterForNthChar(size_t n) { return begin() + n; }
+  const_iterator GetIterForNthChar(size_t n) const { return begin() + n; }

 #endif // wxUSE_UNICODE_UTF8/!wxUSE_UNICODE_UTF8
 
   #undef WX_STR_ITERATOR_TAG
 #endif // wxUSE_UNICODE_UTF8/!wxUSE_UNICODE_UTF8
 
   #undef WX_STR_ITERATOR_TAG


@@ -863,7 +1114,7 @@ public:
   public:
       typedef T iterator_type;
 
   public:
       typedef T iterator_type;
 

-      typedef typename T::iterator_category iterator_category;
+      WX_DEFINE_ITERATOR_CATEGORY(typename T::iterator_category)

       typedef typename T::value_type value_type;
       typedef typename T::difference_type difference_type;
       typedef typename T::reference reference;
       typedef typename T::value_type value_type;
       typedef typename T::difference_type difference_type;
       typedef typename T::reference reference;


@@ -1035,6 +1286,17 @@ public:
   wxString(const wxString& str, size_t nLength)
     { assign(str, nLength); }
 
   wxString(const wxString& str, size_t nLength)
     { assign(str, nLength); }
 

+
+#if wxUSE_STRING_POS_CACHE
+  ~wxString()
+  {
+      // we need to invalidate our cache entry as another string could be
+      // recreated at the same address (unlikely, but still possible, with the
+      // heap-allocated strings but perfectly common with stack-allocated ones)
+      InvalidateCache();
+  }
+#endif // wxUSE_STRING_POS_CACHE
+

   // even if we're not built with wxUSE_STL == 1 it is very convenient to allow
   // implicit conversions from std::string to wxString and vice verse as this
   // allows to use the same strings in non-GUI and GUI code, however we don't
   // even if we're not built with wxUSE_STL == 1 it is very convenient to allow
   // implicit conversions from std::string to wxString and vice verse as this
   // allows to use the same strings in non-GUI and GUI code, however we don't


@@ -1110,7 +1372,32 @@ public:
 
   // std::string methods:
 #if wxUSE_UNICODE_UTF8
 
   // std::string methods:
 #if wxUSE_UNICODE_UTF8

-  size_t length() const { return end() - begin(); } // FIXME-UTF8: optimize!
+  size_t length() const
+  {
+#if wxUSE_STRING_POS_CACHE
+      wxCACHE_PROFILE_FIELD_INC(lentot);
+
+      Cache::Element * const cache = GetCacheElement();
+
+      if ( cache->len == npos )
+      {
+          // it's probably not worth trying to be clever and using cache->pos
+          // here as it's probably 0 anyhow -- you usually call length() before
+          // starting to index the string
+          cache->len = end() - begin();
+      }
+      else
+      {
+          wxCACHE_PROFILE_FIELD_INC(lenhits);
+
+          wxSTRING_CACHE_ASSERT( (int)cache->len == end() - begin() );
+      }
+
+      return cache->len;
+#else // !wxUSE_STRING_POS_CACHE
+      return end() - begin();
+#endif // wxUSE_STRING_POS_CACHE/!wxUSE_STRING_POS_CACHE
+  }

 #else
   size_t length() const { return m_impl.length(); }
 #endif
 #else
   size_t length() const { return m_impl.length(); }
 #endif


@@ -1120,8 +1407,9 @@ public:
 
   bool empty() const { return m_impl.empty(); }
 
 
   bool empty() const { return m_impl.empty(); }
 

-  size_type capacity() const { return m_impl.capacity(); } // FIXME-UTF8
-  void reserve(size_t sz) { m_impl.reserve(sz); } // FIXME-UTF8
+  // NB: these methods don't have a well-defined meaning in UTF-8 case
+  size_type capacity() const { return m_impl.capacity(); }
+  void reserve(size_t sz) { m_impl.reserve(sz); }

 
   void resize(size_t nSize, wxUniChar ch = wxT('\0'))
   {
 
   void resize(size_t nSize, wxUniChar ch = wxT('\0'))
   {


@@ -1132,7 +1420,7 @@ public:
 #if wxUSE_UNICODE_UTF8
     if ( nSize < len )
     {
 #if wxUSE_UNICODE_UTF8
     if ( nSize < len )
     {

-        wxSTRING_INVALIDATE_INDEX_CACHE();
+        wxSTRING_INVALIDATE_CACHE();

 
         // we can't use wxStringImpl::resize() for truncating the string as it
         // counts in bytes, not characters
 
         // we can't use wxStringImpl::resize() for truncating the string as it
         // counts in bytes, not characters


@@ -1143,10 +1431,16 @@ public:
     // we also can't use (presumably more efficient) resize() if we have to
     // append characters taking more than one byte
     if ( !ch.IsAscii() )
     // we also can't use (presumably more efficient) resize() if we have to
     // append characters taking more than one byte
     if ( !ch.IsAscii() )

+    {

         append(nSize - len, ch);
         append(nSize - len, ch);

-    else
+    }
+    else // can use (presumably faster) resize() version

 #endif // wxUSE_UNICODE_UTF8
 #endif // wxUSE_UNICODE_UTF8

+    {
+        wxSTRING_INVALIDATE_CACHED_LENGTH();
+

         m_impl.resize(nSize, (wxStringCharType)ch);
         m_impl.resize(nSize, (wxStringCharType)ch);

+    }

   }
 
   wxString substr(size_t nStart = 0, size_t nLen = npos) const
   }
 
   wxString substr(size_t nStart = 0, size_t nLen = npos) const


@@ -1166,12 +1460,7 @@ public:
     // truncate the string to given length
   wxString& Truncate(size_t uiLen);
     // empty string contents
     // truncate the string to given length
   wxString& Truncate(size_t uiLen);
     // empty string contents

-  void Empty()
-  {
-    Truncate(0);
-
-    wxASSERT_MSG( empty(), _T("string not empty after call to Empty()?") );
-  }
+  void Empty() { clear(); }

     // empty the string and free memory
   void Clear() { clear(); }
 
     // empty the string and free memory
   void Clear() { clear(); }
 


@@ -1191,27 +1480,12 @@ public:
       { return at(n); }
     // read/write access
     wxUniCharRef at(size_t n)
       { return at(n); }
     // read/write access
     wxUniCharRef at(size_t n)

-      { return *GetNthIter(n); }
+      { return *GetIterForNthChar(n); }

     wxUniCharRef GetWritableChar(size_t n)
       { return at(n); }
     // write access
     void SetChar(size_t n, wxUniChar ch)
     wxUniCharRef GetWritableChar(size_t n)
       { return at(n); }
     // write access
     void SetChar(size_t n, wxUniChar ch)

-    {
-        wxUniCharRef ref(at(n));
-
-#if wxUSE_UNICODE_UTF8
-        // if the new character takes the same number of bytes as the old one,
-        // we can avoid invalidating the index cache and it's an important case
-        // as it is exercised by a simple for loop using indices
-        if ( wxStringOperations::GetUtf8CharLength(ref)
-                != wxStringOperations::GetUtf8CharLength(ch) )
-        {
-            wxSTRING_INVALIDATE_INDEX_CACHE();
-        }
-#endif // wxUSE_UNICODE_UTF8
-
-        ref = ch;
-    }
+      { at(n) = ch; }

 
     // get last character
     wxUniChar Last() const
 
     // get last character
     wxUniChar Last() const


@@ -1254,11 +1528,53 @@ public:
       { return at(n); }
 #endif // size_t != unsigned int
 
       { return at(n); }
 #endif // size_t != unsigned int
 

-    // explicit conversion to C string (use this with printf()!)
+
+    /*
+        Overview of wxString conversions, implicit and explicit:
+
+        - wxString has a std::[w]string-like c_str() method, however it does
+          not return a C-style string directly but instead returns wxCStrData
+          helper object which is convertible to either "char *" narrow string
+          or "wchar_t *" wide string. Usually the correct conversion will be
+          applied by the compiler automatically but if this doesn't happen you
+          need to explicitly choose one using wxCStrData::AsChar() or AsWChar()
+          methods or another wxString conversion function.
+
+        - One of the places where the conversion does *NOT* happen correctly is
+          when c_str() is passed to a vararg function such as printf() so you
+          must *NOT* use c_str() with them. Either use wxPrintf() (all wx
+          functions do handle c_str() correctly, even if they appear to be
+          vararg (but they're not, really)) or add an explicit AsChar() or, if
+          compatibility with previous wxWidgets versions is important, add a
+          cast to "const char *".
+
+        - In non-STL mode only, wxString is also implicitly convertible to
+          wxCStrData. The same warning as above applies.
+
+        - c_str() is polymorphic as it can be converted to either narrow or
+          wide string. If you explicitly need one or the other, choose to use
+          mb_str() (for narrow) or wc_str() (for wide) instead. Notice that
+          these functions can return either the pointer to string directly (if
+          this is what the string uses internally) or a temporary buffer
+          containing the string and convertible to it. Again, conversion will
+          usually be done automatically by the compiler but beware of the
+          vararg functions: you need an explicit cast when using them.
+
+        - There are also non-const versions of mb_str() and wc_str() called
+          char_str() and wchar_str(). They are only meant to be used with
+          non-const-correct functions and they always return buffers.
+
+        - Finally wx_str() returns whatever string representation is used by
+          wxString internally. It may be either a narrow or wide string
+          depending on wxWidgets build mode but it will always be a raw pointer
+          (and not a buffer).
+     */
+
+    // explicit conversion to wxCStrData

     wxCStrData c_str() const { return wxCStrData(this); }
     wxCStrData data() const { return c_str(); }
 
     wxCStrData c_str() const { return wxCStrData(this); }
     wxCStrData data() const { return c_str(); }
 

-    // implicit conversion to C string
+    // implicit conversion to wxCStrData

     operator wxCStrData() const { return c_str(); }
 
     // the first two operators conflict with operators for conversion to
     operator wxCStrData() const { return c_str(); }
 
     // the first two operators conflict with operators for conversion to


@@ -1494,7 +1810,7 @@ public:
     const wchar_t* t_str() const { return wx_str(); }
 #else
     const char* t_str() const { return wx_str(); }
     const wchar_t* t_str() const { return wx_str(); }
 #else
     const char* t_str() const { return wx_str(); }

-#endif 
+#endif

 
 
   // overloaded assignment
 
 
   // overloaded assignment


@@ -1503,7 +1819,7 @@ public:
   {
     if ( this != &stringSrc )
     {
   {
     if ( this != &stringSrc )
     {

-        wxSTRING_INVALIDATE_INDEX_CACHE();
+        wxSTRING_INVALIDATE_CACHE();

 
         m_impl = stringSrc.m_impl;
     }
 
         m_impl = stringSrc.m_impl;
     }


@@ -1516,7 +1832,7 @@ public:
     // from a character
   wxString& operator=(wxUniChar ch)
   {
     // from a character
   wxString& operator=(wxUniChar ch)
   {

-    wxSTRING_INVALIDATE_INDEX_CACHE();
+    wxSTRING_INVALIDATE_CACHE();

 
 #if wxUSE_UNICODE_UTF8
     if ( !ch.IsAscii() )
 
 #if wxUSE_UNICODE_UTF8
     if ( !ch.IsAscii() )


@@ -1540,7 +1856,7 @@ public:
 #if wxUSE_STL_BASED_WXSTRING
   wxString& operator=(const char *psz)
   {
 #if wxUSE_STL_BASED_WXSTRING
   wxString& operator=(const char *psz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       if ( psz )
           m_impl = ImplStr(psz);
 
       if ( psz )
           m_impl = ImplStr(psz);


@@ -1552,7 +1868,7 @@ public:
 
   wxString& operator=(const wchar_t *pwz)
   {
 
   wxString& operator=(const wchar_t *pwz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       if ( pwz )
           m_impl = ImplStr(pwz);
 
       if ( pwz )
           m_impl = ImplStr(pwz);


@@ -1564,7 +1880,7 @@ public:
 #else // !wxUSE_STL_BASED_WXSTRING
   wxString& operator=(const char *psz)
   {
 #else // !wxUSE_STL_BASED_WXSTRING
   wxString& operator=(const char *psz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl = ImplStr(psz);
 
 
       m_impl = ImplStr(psz);
 


@@ -1573,7 +1889,7 @@ public:
 
   wxString& operator=(const wchar_t *pwz)
   {
 
   wxString& operator=(const wchar_t *pwz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl = ImplStr(pwz);
 
 
       m_impl = ImplStr(pwz);
 


@@ -1803,16 +2119,16 @@ public:
   wxString Left(size_t nCount) const;
       // get last nCount characters
   wxString Right(size_t nCount) const;
   wxString Left(size_t nCount) const;
       // get last nCount characters
   wxString Right(size_t nCount) const;

-      // get all characters before the first occurance of ch
+      // get all characters before the first occurrence of ch

       // (returns the whole string if ch not found)
   wxString BeforeFirst(wxUniChar ch) const;
       // (returns the whole string if ch not found)
   wxString BeforeFirst(wxUniChar ch) const;

-      // get all characters before the last occurence of ch
+      // get all characters before the last occurrence of ch

       // (returns empty string if ch not found)
   wxString BeforeLast(wxUniChar ch) const;
       // (returns empty string if ch not found)
   wxString BeforeLast(wxUniChar ch) const;

-      // get all characters after the first occurence of ch
+      // get all characters after the first occurrence of ch

       // (returns empty string if ch not found)
   wxString AfterFirst(wxUniChar ch) const;
       // (returns empty string if ch not found)
   wxString AfterFirst(wxUniChar ch) const;

-      // get all characters after the last occurence of ch
+      // get all characters after the last occurrence of ch

       // (returns the whole string if ch not found)
   wxString AfterLast(wxUniChar ch) const;
 
       // (returns the whole string if ch not found)
   wxString AfterLast(wxUniChar ch) const;
 


@@ -1877,7 +2193,7 @@ public:
   int Find(const wxWCharBuffer& sub) const
     { return Find(sub.data()); }
 
   int Find(const wxWCharBuffer& sub) const
     { return Find(sub.data()); }
 

-      // replace first (or all of bReplaceAll) occurences of substring with
+      // replace first (or all of bReplaceAll) occurrences of substring with

       // another string, returns the number of replacements made
   size_t Replace(const wxString& strOld,
                  const wxString& strNew,
       // another string, returns the number of replacements made
   size_t Replace(const wxString& strOld,
                  const wxString& strNew,


@@ -2067,30 +2383,54 @@ public:
     // append elements str[pos], ..., str[pos+n]
   wxString& append(const wxString& str, size_t pos, size_t n)
   {
     // append elements str[pos], ..., str[pos+n]
   wxString& append(const wxString& str, size_t pos, size_t n)
   {

-    size_t from, len;
-    str.PosLenToImpl(pos, n, &from, &len);
-    m_impl.append(str.m_impl, from, len);
-    return *this;
+      wxSTRING_UPDATE_CACHED_LENGTH(n);
+
+      size_t from, len;
+      str.PosLenToImpl(pos, n, &from, &len);
+      m_impl.append(str.m_impl, from, len);
+      return *this;

   }
     // append a string
   wxString& append(const wxString& str)
   }
     // append a string
   wxString& append(const wxString& str)

-    { m_impl.append(str.m_impl); return *this; }
+  {
+      wxSTRING_UPDATE_CACHED_LENGTH(str.length());
+
+      m_impl.append(str.m_impl);
+      return *this;
+  }
+

     // append first n (or all if n == npos) characters of sz
   wxString& append(const char *sz)
     // append first n (or all if n == npos) characters of sz
   wxString& append(const char *sz)

-    { m_impl.append(ImplStr(sz)); return *this; }
+  {
+      wxSTRING_INVALIDATE_CACHED_LENGTH();
+
+      m_impl.append(ImplStr(sz));
+      return *this;
+  }
+

   wxString& append(const wchar_t *sz)
   wxString& append(const wchar_t *sz)

-    { m_impl.append(ImplStr(sz)); return *this; }
+  {
+      wxSTRING_INVALIDATE_CACHED_LENGTH();
+
+      m_impl.append(ImplStr(sz));
+      return *this;
+  }
+

   wxString& append(const char *sz, size_t n)
   {
   wxString& append(const char *sz, size_t n)
   {

-    SubstrBufFromMB str(ImplStr(sz, n));
-    m_impl.append(str.data, str.len);
-    return *this;
+      wxSTRING_INVALIDATE_CACHED_LENGTH();
+
+      SubstrBufFromMB str(ImplStr(sz, n));
+      m_impl.append(str.data, str.len);
+      return *this;

   }
   wxString& append(const wchar_t *sz, size_t n)
   {
   }
   wxString& append(const wchar_t *sz, size_t n)
   {

-    SubstrBufFromWC str(ImplStr(sz, n));
-    m_impl.append(str.data, str.len);
-    return *this;
+      wxSTRING_UPDATE_CACHED_LENGTH(n);
+
+      SubstrBufFromWC str(ImplStr(sz, n));
+      m_impl.append(str.data, str.len);
+      return *this;

   }
 
   wxString& append(const wxCStrData& str)
   }
 
   wxString& append(const wxCStrData& str)


@@ -2110,13 +2450,23 @@ public:
   wxString& append(size_t n, wxUniChar ch)
   {
 #if wxUSE_UNICODE_UTF8
   wxString& append(size_t n, wxUniChar ch)
   {
 #if wxUSE_UNICODE_UTF8

-    if ( !ch.IsAscii() )
-        m_impl.append(wxStringOperations::EncodeNChars(n, ch));
-    else
+      if ( !ch.IsAscii() )
+      {
+          wxSTRING_INVALIDATE_CACHED_LENGTH();
+
+          m_impl.append(wxStringOperations::EncodeNChars(n, ch));
+      }
+      else // ASCII

 #endif
 #endif

-        m_impl.append(n, (wxStringCharType)ch);
-    return *this;
+      {
+          wxSTRING_UPDATE_CACHED_LENGTH(n);
+
+          m_impl.append(n, (wxStringCharType)ch);
+      }
+
+      return *this;

   }
   }

+

   wxString& append(size_t n, wxUniCharRef ch)
     { return append(n, wxUniChar(ch)); }
   wxString& append(size_t n, char ch)
   wxString& append(size_t n, wxUniCharRef ch)
     { return append(n, wxUniChar(ch)); }
   wxString& append(size_t n, char ch)


@@ -2128,7 +2478,12 @@ public:
 
     // append from first to last
   wxString& append(const_iterator first, const_iterator last)
 
     // append from first to last
   wxString& append(const_iterator first, const_iterator last)

-    { m_impl.append(first.impl(), last.impl()); return *this; }
+  {
+      wxSTRING_INVALIDATE_CACHED_LENGTH();
+
+      m_impl.append(first.impl(), last.impl());
+      return *this;
+  }

 #if WXWIN_COMPATIBILITY_STRING_PTR_AS_ITER
   wxString& append(const char *first, const char *last)
     { return append(first, last - first); }
 #if WXWIN_COMPATIBILITY_STRING_PTR_AS_ITER
   wxString& append(const char *first, const char *last)
     { return append(first, last - first); }


@@ -2141,7 +2496,7 @@ public:
     // same as `this_string = str'
   wxString& assign(const wxString& str)
   {
     // same as `this_string = str'
   wxString& assign(const wxString& str)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_SET_CACHED_LENGTH(str.length());

 
       m_impl = str.m_impl;
 
 
       m_impl = str.m_impl;
 


@@ -2150,7 +2505,7 @@ public:
 
   wxString& assign(const wxString& str, size_t len)
   {
 
   wxString& assign(const wxString& str, size_t len)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_SET_CACHED_LENGTH(len);

 
       m_impl.assign(str.m_impl, 0, str.LenToImpl(len));
 
 
       m_impl.assign(str.m_impl, 0, str.LenToImpl(len));
 


@@ -2160,18 +2515,21 @@ public:
     // same as ` = str[pos..pos + n]
   wxString& assign(const wxString& str, size_t pos, size_t n)
   {
     // same as ` = str[pos..pos + n]
   wxString& assign(const wxString& str, size_t pos, size_t n)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
-

       size_t from, len;
       str.PosLenToImpl(pos, n, &from, &len);
       m_impl.assign(str.m_impl, from, len);
       size_t from, len;
       str.PosLenToImpl(pos, n, &from, &len);
       m_impl.assign(str.m_impl, from, len);

+
+      // it's important to call this after PosLenToImpl() above in case str is
+      // the same string as this one
+      wxSTRING_SET_CACHED_LENGTH(n);
+

       return *this;
   }
 
     // same as `= first n (or all if n == npos) characters of sz'
   wxString& assign(const char *sz)
   {
       return *this;
   }
 
     // same as `= first n (or all if n == npos) characters of sz'
   wxString& assign(const char *sz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.assign(ImplStr(sz));
 
 
       m_impl.assign(ImplStr(sz));
 


@@ -2180,7 +2538,7 @@ public:
 
   wxString& assign(const wchar_t *sz)
   {
 
   wxString& assign(const wchar_t *sz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.assign(ImplStr(sz));
 
 
       m_impl.assign(ImplStr(sz));
 


@@ -2189,7 +2547,7 @@ public:
 
   wxString& assign(const char *sz, size_t n)
   {
 
   wxString& assign(const char *sz, size_t n)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_SET_CACHED_LENGTH(n);

 
       SubstrBufFromMB str(ImplStr(sz, n));
       m_impl.assign(str.data, str.len);
 
       SubstrBufFromMB str(ImplStr(sz, n));
       m_impl.assign(str.data, str.len);


@@ -2199,7 +2557,7 @@ public:
 
   wxString& assign(const wchar_t *sz, size_t n)
   {
 
   wxString& assign(const wchar_t *sz, size_t n)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_SET_CACHED_LENGTH(n);

 
       SubstrBufFromWC str(ImplStr(sz, n));
       m_impl.assign(str.data, str.len);
 
       SubstrBufFromWC str(ImplStr(sz, n));
       m_impl.assign(str.data, str.len);


@@ -2223,15 +2581,16 @@ public:
     // same as `= n copies of ch'
   wxString& assign(size_t n, wxUniChar ch)
   {
     // same as `= n copies of ch'
   wxString& assign(size_t n, wxUniChar ch)
   {

-    wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_SET_CACHED_LENGTH(n);

 
 #if wxUSE_UNICODE_UTF8
 
 #if wxUSE_UNICODE_UTF8

-    if ( !ch.IsAscii() )
-        m_impl.assign(wxStringOperations::EncodeNChars(n, ch));
-    else
+      if ( !ch.IsAscii() )
+          m_impl.assign(wxStringOperations::EncodeNChars(n, ch));
+      else

 #endif
 #endif

-        m_impl.assign(n, (wxStringCharType)ch);
-    return *this;
+          m_impl.assign(n, (wxStringCharType)ch);
+
+      return *this;

   }
 
   wxString& assign(size_t n, wxUniCharRef ch)
   }
 
   wxString& assign(size_t n, wxUniCharRef ch)


@@ -2246,7 +2605,7 @@ public:
     // assign from first to last
   wxString& assign(const_iterator first, const_iterator last)
   {
     // assign from first to last
   wxString& assign(const_iterator first, const_iterator last)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.assign(first.impl(), last.impl());
 
 
       m_impl.assign(first.impl(), last.impl());
 


@@ -2284,11 +2643,11 @@ public:
 
     // insert another string
   wxString& insert(size_t nPos, const wxString& str)
 
     // insert another string
   wxString& insert(size_t nPos, const wxString& str)

-    { insert(GetNthIter(nPos), str.begin(), str.end()); return *this; }
+    { insert(GetIterForNthChar(nPos), str.begin(), str.end()); return *this; }

     // insert n chars of str starting at nStart (in str)
   wxString& insert(size_t nPos, const wxString& str, size_t nStart, size_t n)
   {
     // insert n chars of str starting at nStart (in str)
   wxString& insert(size_t nPos, const wxString& str, size_t nStart, size_t n)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_UPDATE_CACHED_LENGTH(n);

 
       size_t from, len;
       str.PosLenToImpl(nStart, n, &from, &len);
 
       size_t from, len;
       str.PosLenToImpl(nStart, n, &from, &len);


@@ -2300,7 +2659,7 @@ public:
     // insert first n (or all if n == npos) characters of sz
   wxString& insert(size_t nPos, const char *sz)
   {
     // insert first n (or all if n == npos) characters of sz
   wxString& insert(size_t nPos, const char *sz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.insert(PosToImpl(nPos), ImplStr(sz));
 
 
       m_impl.insert(PosToImpl(nPos), ImplStr(sz));
 


@@ -2309,14 +2668,14 @@ public:
 
   wxString& insert(size_t nPos, const wchar_t *sz)
   {
 
   wxString& insert(size_t nPos, const wchar_t *sz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.insert(PosToImpl(nPos), ImplStr(sz)); return *this;
   }
 
   wxString& insert(size_t nPos, const char *sz, size_t n)
   {
 
       m_impl.insert(PosToImpl(nPos), ImplStr(sz)); return *this;
   }
 
   wxString& insert(size_t nPos, const char *sz, size_t n)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_UPDATE_CACHED_LENGTH(n);

 
       SubstrBufFromMB str(ImplStr(sz, n));
       m_impl.insert(PosToImpl(nPos), str.data, str.len);
 
       SubstrBufFromMB str(ImplStr(sz, n));
       m_impl.insert(PosToImpl(nPos), str.data, str.len);


@@ -2326,7 +2685,7 @@ public:
 
   wxString& insert(size_t nPos, const wchar_t *sz, size_t n)
   {
 
   wxString& insert(size_t nPos, const wchar_t *sz, size_t n)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_UPDATE_CACHED_LENGTH(n);

 
       SubstrBufFromWC str(ImplStr(sz, n));
       m_impl.insert(PosToImpl(nPos), str.data, str.len);
 
       SubstrBufFromWC str(ImplStr(sz, n));
       m_impl.insert(PosToImpl(nPos), str.data, str.len);


@@ -2337,36 +2696,36 @@ public:
     // insert n copies of ch
   wxString& insert(size_t nPos, size_t n, wxUniChar ch)
   {
     // insert n copies of ch
   wxString& insert(size_t nPos, size_t n, wxUniChar ch)
   {

-    wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_UPDATE_CACHED_LENGTH(n);

 
 #if wxUSE_UNICODE_UTF8
 
 #if wxUSE_UNICODE_UTF8

-    if ( !ch.IsAscii() )
-        m_impl.insert(PosToImpl(nPos), wxStringOperations::EncodeNChars(n, ch));
-    else
+      if ( !ch.IsAscii() )
+          m_impl.insert(PosToImpl(nPos), wxStringOperations::EncodeNChars(n, ch));
+      else

 #endif
 #endif

-        m_impl.insert(PosToImpl(nPos), n, (wxStringCharType)ch);
-    return *this;
+          m_impl.insert(PosToImpl(nPos), n, (wxStringCharType)ch);
+      return *this;

   }
 
   iterator insert(iterator it, wxUniChar ch)
   {
   }
 
   iterator insert(iterator it, wxUniChar ch)
   {

-    wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_UPDATE_CACHED_LENGTH(1);

 
 #if wxUSE_UNICODE_UTF8
 
 #if wxUSE_UNICODE_UTF8

-    if ( !ch.IsAscii() )
-    {
-        size_t pos = IterToImplPos(it);
-        m_impl.insert(pos, wxStringOperations::EncodeChar(ch));
-        return iterator(this, m_impl.begin() + pos);
-    }
-    else
+      if ( !ch.IsAscii() )
+      {
+          size_t pos = IterToImplPos(it);
+          m_impl.insert(pos, wxStringOperations::EncodeChar(ch));
+          return iterator(this, m_impl.begin() + pos);
+      }
+      else

 #endif
 #endif

-        return iterator(this, m_impl.insert(it.impl(), (wxStringCharType)ch));
+          return iterator(this, m_impl.insert(it.impl(), (wxStringCharType)ch));

   }
 
   void insert(iterator it, const_iterator first, const_iterator last)
   {
   }
 
   void insert(iterator it, const_iterator first, const_iterator last)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.insert(it.impl(), first.impl(), last.impl());
   }
 
       m_impl.insert(it.impl(), first.impl(), last.impl());
   }


@@ -2382,20 +2741,20 @@ public:
 
   void insert(iterator it, size_type n, wxUniChar ch)
   {
 
   void insert(iterator it, size_type n, wxUniChar ch)
   {

-    wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_UPDATE_CACHED_LENGTH(n);

 
 #if wxUSE_UNICODE_UTF8
 
 #if wxUSE_UNICODE_UTF8

-    if ( !ch.IsAscii() )
-        m_impl.insert(IterToImplPos(it), wxStringOperations::EncodeNChars(n, ch));
-    else
+      if ( !ch.IsAscii() )
+          m_impl.insert(IterToImplPos(it), wxStringOperations::EncodeNChars(n, ch));
+      else

 #endif
 #endif

-        m_impl.insert(it.impl(), n, (wxStringCharType)ch);
+          m_impl.insert(it.impl(), n, (wxStringCharType)ch);

   }
 
     // delete characters from nStart to nStart + nLen
   wxString& erase(size_type pos = 0, size_type n = npos)
   {
   }
 
     // delete characters from nStart to nStart + nLen
   wxString& erase(size_type pos = 0, size_type n = npos)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       size_t from, len;
       PosLenToImpl(pos, n, &from, &len);
 
       size_t from, len;
       PosLenToImpl(pos, n, &from, &len);


@@ -2407,14 +2766,14 @@ public:
     // delete characters from first up to last
   iterator erase(iterator first, iterator last)
   {
     // delete characters from first up to last
   iterator erase(iterator first, iterator last)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       return iterator(this, m_impl.erase(first.impl(), last.impl()));
   }
 
   iterator erase(iterator first)
   {
 
       return iterator(this, m_impl.erase(first.impl(), last.impl()));
   }
 
   iterator erase(iterator first)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_UPDATE_CACHED_LENGTH(-1);

 
       return iterator(this, m_impl.erase(first.impl()));
   }
 
       return iterator(this, m_impl.erase(first.impl()));
   }


@@ -2424,7 +2783,7 @@ public:
 #else
   void clear()
   {
 #else
   void clear()
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_SET_CACHED_LENGTH(0);

 
       m_impl.clear();
   }
 
       m_impl.clear();
   }


@@ -2433,7 +2792,7 @@ public:
     // replaces the substring of length nLen starting at nStart
   wxString& replace(size_t nStart, size_t nLen, const char* sz)
   {
     // replaces the substring of length nLen starting at nStart
   wxString& replace(size_t nStart, size_t nLen, const char* sz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);
 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);


@@ -2444,7 +2803,7 @@ public:
 
   wxString& replace(size_t nStart, size_t nLen, const wchar_t* sz)
   {
 
   wxString& replace(size_t nStart, size_t nLen, const wchar_t* sz)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);
 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);


@@ -2456,7 +2815,7 @@ public:
     // replaces the substring of length nLen starting at nStart
   wxString& replace(size_t nStart, size_t nLen, const wxString& str)
   {
     // replaces the substring of length nLen starting at nStart
   wxString& replace(size_t nStart, size_t nLen, const wxString& str)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);
 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);


@@ -2468,7 +2827,7 @@ public:
     // replaces the substring with nCount copies of ch
   wxString& replace(size_t nStart, size_t nLen, size_t nCount, wxUniChar ch)
   {
     // replaces the substring with nCount copies of ch
   wxString& replace(size_t nStart, size_t nLen, size_t nCount, wxUniChar ch)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);
 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);


@@ -2486,7 +2845,7 @@ public:
   wxString& replace(size_t nStart, size_t nLen,
                     const wxString& str, size_t nStart2, size_t nLen2)
   {
   wxString& replace(size_t nStart, size_t nLen,
                     const wxString& str, size_t nStart2, size_t nLen2)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);
 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);


@@ -2503,7 +2862,7 @@ public:
   wxString& replace(size_t nStart, size_t nLen,
                     const char* sz, size_t nCount)
   {
   wxString& replace(size_t nStart, size_t nLen,
                     const char* sz, size_t nCount)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);
 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);


@@ -2518,7 +2877,7 @@ public:
   wxString& replace(size_t nStart, size_t nLen,
                     const wchar_t* sz, size_t nCount)
   {
   wxString& replace(size_t nStart, size_t nLen,
                     const wchar_t* sz, size_t nCount)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);
 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);


@@ -2533,7 +2892,7 @@ public:
   wxString& replace(size_t nStart, size_t nLen,
                     const wxString& s, size_t nCount)
   {
   wxString& replace(size_t nStart, size_t nLen,
                     const wxString& s, size_t nCount)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);
 
       size_t from, len;
       PosLenToImpl(nStart, nLen, &from, &len);


@@ -2544,7 +2903,7 @@ public:
 
   wxString& replace(iterator first, iterator last, const char* s)
   {
 
   wxString& replace(iterator first, iterator last, const char* s)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.replace(first.impl(), last.impl(), ImplStr(s));
 
 
       m_impl.replace(first.impl(), last.impl(), ImplStr(s));
 


@@ -2553,7 +2912,7 @@ public:
 
   wxString& replace(iterator first, iterator last, const wchar_t* s)
   {
 
   wxString& replace(iterator first, iterator last, const wchar_t* s)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.replace(first.impl(), last.impl(), ImplStr(s));
 
 
       m_impl.replace(first.impl(), last.impl(), ImplStr(s));
 


@@ -2562,7 +2921,7 @@ public:
 
   wxString& replace(iterator first, iterator last, const char* s, size_type n)
   {
 
   wxString& replace(iterator first, iterator last, const char* s, size_type n)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       SubstrBufFromMB str(ImplStr(s, n));
       m_impl.replace(first.impl(), last.impl(), str.data, str.len);
 
       SubstrBufFromMB str(ImplStr(s, n));
       m_impl.replace(first.impl(), last.impl(), str.data, str.len);


@@ -2572,7 +2931,7 @@ public:
 
   wxString& replace(iterator first, iterator last, const wchar_t* s, size_type n)
   {
 
   wxString& replace(iterator first, iterator last, const wchar_t* s, size_type n)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       SubstrBufFromWC str(ImplStr(s, n));
       m_impl.replace(first.impl(), last.impl(), str.data, str.len);
 
       SubstrBufFromWC str(ImplStr(s, n));
       m_impl.replace(first.impl(), last.impl(), str.data, str.len);


@@ -2582,7 +2941,7 @@ public:
 
   wxString& replace(iterator first, iterator last, const wxString& s)
   {
 
   wxString& replace(iterator first, iterator last, const wxString& s)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.replace(first.impl(), last.impl(), s.m_impl);
 
 
       m_impl.replace(first.impl(), last.impl(), s.m_impl);
 


@@ -2591,7 +2950,7 @@ public:
 
   wxString& replace(iterator first, iterator last, size_type n, wxUniChar ch)
   {
 
   wxString& replace(iterator first, iterator last, size_type n, wxUniChar ch)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
 #if wxUSE_UNICODE_UTF8
       if ( !ch.IsAscii() )
 
 #if wxUSE_UNICODE_UTF8
       if ( !ch.IsAscii() )


@@ -2607,7 +2966,7 @@ public:
   wxString& replace(iterator first, iterator last,
                     const_iterator first1, const_iterator last1)
   {
   wxString& replace(iterator first, iterator last,
                     const_iterator first1, const_iterator last1)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.replace(first.impl(), last.impl(), first1.impl(), last1.impl());
 
 
       m_impl.replace(first.impl(), last.impl(), first1.impl(), last1.impl());
 


@@ -2624,7 +2983,13 @@ public:
   // swap two strings
   void swap(wxString& str)
   {
   // swap two strings
   void swap(wxString& str)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+#if wxUSE_STRING_POS_CACHE
+      // we modify not only this string but also the other one directly so we
+      // need to invalidate cache for both of them (we could also try to
+      // exchange their cache entries but it seems unlikely to be worth it)
+      InvalidateCache();
+      str.InvalidateCache();
+#endif // wxUSE_STRING_POS_CACHE

 
       m_impl.swap(str.m_impl);
   }
 
       m_impl.swap(str.m_impl);
   }


@@ -2651,7 +3016,7 @@ public:
   size_t find(const wxCStrData& s, size_t nStart = 0, size_t n = npos) const
     { return find(s.AsWChar(), nStart, n); }
 
   size_t find(const wxCStrData& s, size_t nStart = 0, size_t n = npos) const
     { return find(s.AsWChar(), nStart, n); }
 

-    // find the first occurence of character ch after nStart
+    // find the first occurrence of character ch after nStart

   size_t find(wxUniChar ch, size_t nStart = 0) const
   {
 #if wxUSE_UNICODE_UTF8
   size_t find(wxUniChar ch, size_t nStart = 0) const
   {
 #if wxUSE_UNICODE_UTF8


@@ -2717,7 +3082,7 @@ public:
   size_t rfind(wchar_t ch, size_t nStart = npos) const
     {  return rfind(wxUniChar(ch), nStart); }
 
   size_t rfind(wchar_t ch, size_t nStart = npos) const
     {  return rfind(wxUniChar(ch), nStart); }
 

-  // find first/last occurence of any character (not) in the set:
+  // find first/last occurrence of any character (not) in the set:

 #if wxUSE_STL_BASED_WXSTRING && !wxUSE_UNICODE_UTF8
   // FIXME-UTF8: this is not entirely correct, because it doesn't work if
   //             sizeof(wchar_t)==2 and surrogates are present in the string;
 #if wxUSE_STL_BASED_WXSTRING && !wxUSE_UNICODE_UTF8
   // FIXME-UTF8: this is not entirely correct, because it doesn't work if
   //             sizeof(wchar_t)==2 and surrogates are present in the string;


@@ -2808,7 +3173,7 @@ public:
   size_t find_last_of(wxUniChar c, size_t nStart = npos) const
     { return rfind(c, nStart); }
 
   size_t find_last_of(wxUniChar c, size_t nStart = npos) const
     { return rfind(c, nStart); }
 

-    // find first/last occurence of any character not in the set
+    // find first/last occurrence of any character not in the set

 
     // as strspn() (starting from nStart), returns npos on failure
   size_t find_first_not_of(const wxString& str, size_t nStart = 0) const
 
     // as strspn() (starting from nStart), returns npos on failure
   size_t find_first_not_of(const wxString& str, size_t nStart = 0) const


@@ -2930,14 +3295,34 @@ public:
 
       // string += string
   wxString& operator+=(const wxString& s)
 
       // string += string
   wxString& operator+=(const wxString& s)

-    { m_impl += s.m_impl; return *this; }
+  {
+      wxSTRING_INVALIDATE_CACHED_LENGTH();
+
+      m_impl += s.m_impl;
+      return *this;
+  }

       // string += C string
   wxString& operator+=(const char *psz)
       // string += C string
   wxString& operator+=(const char *psz)

-    { m_impl += ImplStr(psz); return *this; }
+  {
+      wxSTRING_INVALIDATE_CACHED_LENGTH();
+
+      m_impl += ImplStr(psz);
+      return *this;
+  }

   wxString& operator+=(const wchar_t *pwz)
   wxString& operator+=(const wchar_t *pwz)

-    { m_impl += ImplStr(pwz); return *this; }
+  {
+      wxSTRING_INVALIDATE_CACHED_LENGTH();
+
+      m_impl += ImplStr(pwz);
+      return *this;
+  }

   wxString& operator+=(const wxCStrData& s)
   wxString& operator+=(const wxCStrData& s)

-    { m_impl += s.AsString().m_impl; return *this; }
+  {
+      wxSTRING_INVALIDATE_CACHED_LENGTH();
+
+      m_impl += s.AsString().m_impl;
+      return *this;
+  }

   wxString& operator+=(const wxCharBuffer& s)
     { return operator+=(s.data()); }
   wxString& operator+=(const wxWCharBuffer& s)
   wxString& operator+=(const wxCharBuffer& s)
     { return operator+=(s.data()); }
   wxString& operator+=(const wxWCharBuffer& s)


@@ -2945,13 +3330,15 @@ public:
       // string += char
   wxString& operator+=(wxUniChar ch)
   {
       // string += char
   wxString& operator+=(wxUniChar ch)
   {

+      wxSTRING_UPDATE_CACHED_LENGTH(1);
+

 #if wxUSE_UNICODE_UTF8
 #if wxUSE_UNICODE_UTF8

-    if ( !ch.IsAscii() )
-        m_impl += wxStringOperations::EncodeChar(ch);
-    else
+      if ( !ch.IsAscii() )
+          m_impl += wxStringOperations::EncodeChar(ch);
+      else

 #endif
 #endif

-        m_impl += (wxStringCharType)ch;
-    return *this;
+          m_impl += (wxStringCharType)ch;
+      return *this;

   }
   wxString& operator+=(wxUniCharRef ch) { return *this += wxUniChar(ch); }
   wxString& operator+=(int ch) { return *this += wxUniChar(ch); }
   }
   wxString& operator+=(wxUniCharRef ch) { return *this += wxUniChar(ch); }
   wxString& operator+=(int ch) { return *this += wxUniChar(ch); }


@@ -2969,14 +3356,14 @@ private:
 
   void DoUngetWriteBuf()
   {
 
   void DoUngetWriteBuf()
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_INVALIDATE_CACHE();

 
       m_impl.DoUngetWriteBuf();
   }
 
   void DoUngetWriteBuf(size_t nLen)
   {
 
       m_impl.DoUngetWriteBuf();
   }
 
   void DoUngetWriteBuf(size_t nLen)
   {

-      wxSTRING_INVALIDATE_INDEX_CACHE();
+      wxSTRING_SET_CACHED_LENGTH(nLen);

 
       m_impl.DoUngetWriteBuf(nLen);
   }
 
       m_impl.DoUngetWriteBuf(nLen);
   }


@@ -3041,7 +3428,7 @@ private:
 
       // copying is disallowed as it would result in more than one pointer into
       // the same linked list
 
       // copying is disallowed as it would result in more than one pointer into
       // the same linked list

-      DECLARE_NO_COPY_CLASS(wxStringIteratorNodeHead)
+      wxDECLARE_NO_COPY_CLASS(wxStringIteratorNodeHead);

   };
 
   wxStringIteratorNodeHead m_iterators;
   };
 
   wxStringIteratorNodeHead m_iterators;


@@ -3184,7 +3571,7 @@ private:
     wxString&         m_str;
     wxStringCharType *m_buf;
 
     wxString&         m_str;
     wxStringCharType *m_buf;
 

-    DECLARE_NO_COPY_CLASS(wxStringInternalBuffer)
+    wxDECLARE_NO_COPY_CLASS(wxStringInternalBuffer);

 };
 
 class wxStringInternalBufferLength
 };
 
 class wxStringInternalBufferLength


@@ -3214,13 +3601,13 @@ private:
     size_t            m_len;
     bool              m_lenSet;
 
     size_t            m_len;
     bool              m_lenSet;
 

-    DECLARE_NO_COPY_CLASS(wxStringInternalBufferLength)
+    wxDECLARE_NO_COPY_CLASS(wxStringInternalBufferLength);

 };
 
 #endif // !wxUSE_STL_BASED_WXSTRING
 
 template<typename T>
 };
 
 #endif // !wxUSE_STL_BASED_WXSTRING
 
 template<typename T>

-class WXDLLIMPEXP_BASE wxStringTypeBufferBase
+class wxStringTypeBufferBase

 {
 public:
     typedef T CharType;
 {
 public:
     typedef T CharType;


@@ -3260,8 +3647,7 @@ protected:
 };
 
 template<typename T>
 };
 
 template<typename T>

-class WXDLLIMPEXP_BASE wxStringTypeBufferLengthBase
-    : public wxStringTypeBufferBase<T>
+class wxStringTypeBufferLengthBase : public wxStringTypeBufferBase<T>

 {
 public:
     wxStringTypeBufferLengthBase(wxString& str, size_t lenWanted = 1024)
 {
 public:
     wxStringTypeBufferLengthBase(wxString& str, size_t lenWanted = 1024)


@@ -3295,7 +3681,7 @@ public:
         this->m_str.assign(this->m_buf.data());
     }
 
         this->m_str.assign(this->m_buf.data());
     }
 

-    DECLARE_NO_COPY_CLASS(wxStringTypeBuffer)
+    wxDECLARE_NO_COPY_CLASS(wxStringTypeBuffer);

 };
 
 template<typename T>
 };
 
 template<typename T>


@@ -3311,7 +3697,7 @@ public:
         this->m_str.assign(this->m_buf.data(), this->m_len);
     }
 
         this->m_str.assign(this->m_buf.data(), this->m_len);
     }
 

-    DECLARE_NO_COPY_CLASS(wxStringTypeBufferLength)
+    wxDECLARE_NO_COPY_CLASS(wxStringTypeBufferLength);

 };
 
 #if wxUSE_STL_BASED_WXSTRING
 };
 
 #if wxUSE_STL_BASED_WXSTRING


@@ -3326,7 +3712,7 @@ public:
     ~wxStringInternalBuffer()
         { m_str.m_impl.assign(m_buf.data()); }
 
     ~wxStringInternalBuffer()
         { m_str.m_impl.assign(m_buf.data()); }
 

-    DECLARE_NO_COPY_CLASS(wxStringInternalBuffer)
+    wxDECLARE_NO_COPY_CLASS(wxStringInternalBuffer);

 };
 
 WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE(
 };
 
 WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE(


@@ -3344,7 +3730,7 @@ public:
         m_str.m_impl.assign(m_buf.data(), m_len);
     }
 
         m_str.m_impl.assign(m_buf.data(), m_len);
     }
 

-    DECLARE_NO_COPY_CLASS(wxStringInternalBufferLength)
+    wxDECLARE_NO_COPY_CLASS(wxStringInternalBufferLength);

 };
 
 #endif // wxUSE_STL_BASED_WXSTRING
 };
 
 #endif // wxUSE_STL_BASED_WXSTRING


@@ -3365,27 +3751,59 @@ typedef wxStringInternalBufferLength          wxUTF8StringBufferLength;
 
 WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxStringTypeBufferBase<char> )
 
 
 WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxStringTypeBufferBase<char> )
 

-class WXDLLIMPEXP_BASE wxUTF8StringBuffer : public wxStringTypeBufferBase<char>
+// Note about inlined dtors in the classes below: this is done not for
+// performance reasons but just to avoid linking errors in the MSVC DLL build
+// under Windows: if a class has non-inline methods it must be declared as
+// being DLL-exported but, due to an extremely interesting feature of MSVC 7
+// and later, any template class which is used as a base of a DLL-exported
+// class is implicitly made DLL-exported too, as explained at the bottom of
+// http://msdn.microsoft.com/en-us/library/twa2aw10.aspx (just to confirm: yes,
+// _inheriting_ from a class can change whether it is being exported from DLL)
+//
+// But this results in link errors because the base template class is not DLL-
+// exported, whether it is declared with WXDLLIMPEXP_BASE or not, because it
+// does have only inline functions. So the simplest fix is to just make all the
+// functions of these classes inline too.
+
+class wxUTF8StringBuffer : public wxStringTypeBufferBase<char>

 {
 public:
     wxUTF8StringBuffer(wxString& str, size_t lenWanted = 1024)
         : wxStringTypeBufferBase<char>(str, lenWanted) {}
 {
 public:
     wxUTF8StringBuffer(wxString& str, size_t lenWanted = 1024)
         : wxStringTypeBufferBase<char>(str, lenWanted) {}

-    ~wxUTF8StringBuffer();
+    ~wxUTF8StringBuffer()
+    {
+        wxMBConvStrictUTF8 conv;
+        size_t wlen = conv.ToWChar(NULL, 0, m_buf);
+        wxCHECK_RET( wlen != wxCONV_FAILED, "invalid UTF-8 data in string buffer?" );
+
+        wxStringInternalBuffer wbuf(m_str, wlen);
+        conv.ToWChar(wbuf, wlen, m_buf);
+    }

 
 

-    DECLARE_NO_COPY_CLASS(wxUTF8StringBuffer)
+    wxDECLARE_NO_COPY_CLASS(wxUTF8StringBuffer);

 };
 
 WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxStringTypeBufferLengthBase<char> )
 
 };
 
 WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxStringTypeBufferLengthBase<char> )
 

-class WXDLLIMPEXP_BASE wxUTF8StringBufferLength
-    : public wxStringTypeBufferLengthBase<char>
+class wxUTF8StringBufferLength : public wxStringTypeBufferLengthBase<char>

 {
 public:
     wxUTF8StringBufferLength(wxString& str, size_t lenWanted = 1024)
         : wxStringTypeBufferLengthBase<char>(str, lenWanted) {}
 {
 public:
     wxUTF8StringBufferLength(wxString& str, size_t lenWanted = 1024)
         : wxStringTypeBufferLengthBase<char>(str, lenWanted) {}

-    ~wxUTF8StringBufferLength();
+    ~wxUTF8StringBufferLength()
+    {
+        wxCHECK_RET(m_lenSet, "length not set");
+
+        wxMBConvStrictUTF8 conv;
+        size_t wlen = conv.ToWChar(NULL, 0, m_buf, m_len);
+        wxCHECK_RET( wlen != wxCONV_FAILED, "invalid UTF-8 data in string buffer?" );
+
+        wxStringInternalBufferLength wbuf(m_str, wlen);
+        conv.ToWChar(wbuf, wlen, m_buf, m_len);
+        wbuf.SetLength(wlen);
+    }

 
 

-    DECLARE_NO_COPY_CLASS(wxUTF8StringBufferLength)
+    wxDECLARE_NO_COPY_CLASS(wxUTF8StringBufferLength);

 };
 #endif // wxUSE_UNICODE_UTF8/wxUSE_UNICODE_WCHAR
 
 };
 #endif // wxUSE_UNICODE_UTF8/wxUSE_UNICODE_WCHAR
 


@@ -3539,7 +3957,7 @@ inline wxCStrData::wxCStrData(const wxCStrData& data)
 inline wxCStrData::~wxCStrData()
 {
     if ( m_owned )
 inline wxCStrData::~wxCStrData()
 {
     if ( m_owned )

-        delete wx_const_cast(wxString*, m_str); // cast to silence warnings
+        delete const_cast<wxString*>(m_str); // cast to silence warnings

 }
 
 // simple cases for AsChar() and AsWChar(), the complicated ones are
 }
 
 // simple cases for AsChar() and AsWChar(), the complicated ones are


@@ -3662,7 +4080,7 @@ void wxStringIteratorNode::DoSet(const wxString *str,
     if ( str )
     {
         m_next = str->m_iterators.ptr;
     if ( str )
     {
         m_next = str->m_iterators.ptr;

-        wx_const_cast(wxString*, m_str)->m_iterators.ptr = this;
+        const_cast<wxString*>(m_str)->m_iterators.ptr = this;

         if ( m_next )
             m_next->m_prev = this;
     }
         if ( m_next )
             m_next->m_prev = this;
     }


@@ -3679,7 +4097,7 @@ void wxStringIteratorNode::clear()
     if ( m_prev )
         m_prev->m_next = m_next;
     else if ( m_str ) // first in the list
     if ( m_prev )
         m_prev->m_next = m_next;
     else if ( m_str ) // first in the list

-        wx_const_cast(wxString*, m_str)->m_iterators.ptr = m_next;
+        const_cast<wxString*>(m_str)->m_iterators.ptr = m_next;

 
     m_next = m_prev = NULL;
     m_citer = NULL;
 
     m_next = m_prev = NULL;
     m_citer = NULL;


@@ -3696,4 +4114,19 @@ void wxStringIteratorNode::clear()
     #include "wx/crt.h"
 #endif
 
     #include "wx/crt.h"
 #endif
 

+// ----------------------------------------------------------------------------
+// Checks on wxString characters
+// ----------------------------------------------------------------------------
+
+template<bool (T)(const wxUniChar& c)>
+    inline bool wxStringCheck(const wxString& val)
+    {
+        for ( wxString::const_iterator i = val.begin();
+              i != val.end();
+              ++i )
+            if (T(*i) == 0)
+                return false;
+        return true;
+    }
+

 #endif  // _WX_WXSTRING_H_
 #endif  // _WX_WXSTRING_H_