From 77a0f3d154af63737a1e8e2e48a6e014ad58fbcb Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Mon, 14 Apr 2008 16:05:50 +0000
Subject: [PATCH] fix bug when appending string to itself (closes bug 1942116)
 [backport of r48302 from trunk]

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@53167 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---
 src/common/string.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/common/string.cpp b/src/common/string.cpp
index e9ca33871f..ea260708d1 100644
--- a/src/common/string.cpp
+++ b/src/common/string.cpp
@@ -844,6 +844,16 @@ bool wxStringBase::ConcatSelf(size_t nSrcLen, const wxChar *pszSrcData,
     size_t nLen = pData->nDataLength;
     size_t nNewLen = nLen + nSrcLen;
 
+    // take special care when appending part of this string to itself: the code
+    // below reallocates our buffer and this invalidates pszSrcData pointer so
+    // we have to copy it in another temporary string in this case (but avoid
+    // doing this unnecessarily)
+    if ( pszSrcData >= m_pchData && pszSrcData < m_pchData + nLen )
+    {
+        wxStringBase tmp(pszSrcData, nSrcLen);
+        return ConcatSelf(nSrcLen, tmp.m_pchData, nSrcLen);
+    }
+
     // alloc new buffer if current is too small
     if ( pData->IsShared() ) {
       STATISTICS_ADD(ConcatHit, 0);