landing string defragmentation patch for bug 231995, r/sr=dbaron,jst,dougt

git-svn-id: svn://10.0.0.236/trunk@152905 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/xpcom/string/src/nsTSubstringTuple.cpp

@@ -0,0 +1,127 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla.
+ *
+ * The Initial Developer of the Original Code is IBM Corporation.
+ * Portions created by IBM Corporation are Copyright (C) 2003
+ * IBM Corporation. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Darin Fisher <darin@meer.net>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+
+  /**
+   * computes the aggregate string length
+   */
+
+nsTSubstringTuple_CharT::size_type
+nsTSubstringTuple_CharT::Length() const
+  {
+    PRUint32 len;
+    if (mHead)
+      len = mHead->Length();
+    else
+      len = TO_SUBSTRING(mFragA).Length();
+
+    return len + TO_SUBSTRING(mFragB).Length();
+  }
+
+
+  /**
+   * writes the aggregate string to the given buffer.  bufLen is assumed
+   * to be equal to or greater than the value returned by the Length()
+   * method.  the string written to |buf| is not null-terminated.
+   */
+
+void
+nsTSubstringTuple_CharT::WriteTo( char_type *buf, PRUint32 bufLen ) const
+  {
+    const substring_type& b = TO_SUBSTRING(mFragB);
+
+    NS_ASSERTION(bufLen >= b.Length(), "buffer too small");
+    PRUint32 headLen = bufLen - b.Length();
+    if (mHead)
+      {
+        mHead->WriteTo(buf, headLen);
+      }
+    else
+      {
+        const substring_type& a = TO_SUBSTRING(mFragA);
+
+        NS_ASSERTION(a.Length() == headLen, "buffer incorrectly sized");
+        char_traits::copy(buf, a.Data(), a.Length());
+      }
+
+    char_traits::copy(buf + headLen, b.Data(), b.Length());
+
+#if 0
+    // we need to write out data into |buf|, ending at |buf+bufLen|.  so our
+    // data needs to precede |buf+bufLen| exactly.  we trust that the buffer
+    // was properly sized!
+
+    const substring_type& b = TO_SUBSTRING(mFragB);
+
+    NS_ASSERTION(bufLen >= b.Length(), "buffer is too small");
+    char_traits::copy(buf + bufLen - b.Length(), b.Data(), b.Length());
+
+    bufLen -= b.Length();
+
+    if (mHead)
+      {
+        mHead->WriteTo(buf, bufLen);
+      }
+    else
+      {
+        const substring_type& a = TO_SUBSTRING(mFragA);
+        NS_ASSERTION(bufLen == a.Length(), "buffer is too small");
+        char_traits::copy(buf, a.Data(), a.Length());
+      }
+#endif
+  }
+
+
+  /**
+   * returns true if this tuple is dependent on (i.e., overlapping with)
+   * the given char sequence.
+   */
+
+PRBool
+nsTSubstringTuple_CharT::IsDependentOn( const char_type *start, const char_type *end ) const
+  {
+    // we start with the right-most fragment since it is faster to check.
+
+    if (TO_SUBSTRING(mFragB).IsDependentOn(start, end))
+      return PR_TRUE;
+
+    if (mHead)
+      return mHead->IsDependentOn(start, end);
+
+    return TO_SUBSTRING(mFragA).IsDependentOn(start, end);
+  }