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diff --git a/src/libs/xpcom18a4/xpcom/io/nsSegmentedBuffer.h b/src/libs/xpcom18a4/xpcom/io/nsSegmentedBuffer.h
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+++ b/src/libs/xpcom18a4/xpcom/io/nsSegmentedBuffer.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* ***** 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.org code.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1998
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of 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 ***** */
+
+#ifndef nsSegmentedBuffer_h__
+#define nsSegmentedBuffer_h__
+
+#include "nsMemory.h"
+#include "prclist.h"
+
+class nsSegmentedBuffer
+{
+public:
+    nsSegmentedBuffer()
+        : mSegmentSize(0), mMaxSize(0), 
+          mSegAllocator(nsnull), mSegmentArray(nsnull),
+          mSegmentArrayCount(0),
+          mFirstSegmentIndex(0), mLastSegmentIndex(0) {}
+
+    ~nsSegmentedBuffer() {
+        Empty();
+        NS_IF_RELEASE(mSegAllocator);
+    }
+
+
+    NS_COM nsresult Init(PRUint32 segmentSize, PRUint32 maxSize,
+                  nsIMemory* allocator = nsnull);
+
+    NS_COM char* AppendNewSegment();   // pushes at end
+
+    // returns true if no more segments remain:
+    PRBool DeleteFirstSegment();  // pops from beginning
+
+    // returns true if no more segments remain:
+    PRBool DeleteLastSegment();  // pops from beginning
+
+    // Call Realloc() on last segment.  This is used to reduce memory
+    // consumption when data is not an exact multiple of segment size.
+    PRBool ReallocLastSegment(size_t newSize);
+
+    NS_COM void Empty();               // frees all segments
+
+    inline PRUint32 GetSegmentCount() {
+        if (mFirstSegmentIndex <= mLastSegmentIndex)
+            return mLastSegmentIndex - mFirstSegmentIndex;
+        else 
+            return mSegmentArrayCount + mLastSegmentIndex - mFirstSegmentIndex;
+    }
+
+    inline PRUint32 GetSegmentSize() { return mSegmentSize; }
+    inline PRUint32 GetMaxSize() { return mMaxSize; }
+    inline PRUint32 GetSize() { return GetSegmentCount() * mSegmentSize; }
+
+    inline char* GetSegment(PRUint32 indx) {
+        NS_ASSERTION(indx < GetSegmentCount(), "index out of bounds");
+        PRInt32 i = ModSegArraySize(mFirstSegmentIndex + (PRInt32)indx);
+        return mSegmentArray[i];
+    }
+
+protected:
+    inline PRInt32 ModSegArraySize(PRInt32 n) {
+        PRUint32 result = n & (mSegmentArrayCount - 1);
+        NS_ASSERTION(result == n % mSegmentArrayCount,
+                     "non-power-of-2 mSegmentArrayCount");
+        return result;
+    }
+
+   inline PRBool IsFull() {
+        return ModSegArraySize(mLastSegmentIndex + 1) == mFirstSegmentIndex;
+    }
+
+protected:
+    PRUint32            mSegmentSize;
+    PRUint32            mMaxSize;
+    nsIMemory*       mSegAllocator;
+    char**              mSegmentArray;
+    PRUint32            mSegmentArrayCount;
+    PRInt32             mFirstSegmentIndex;
+    PRInt32             mLastSegmentIndex;
+};
+
+// NS_SEGMENTARRAY_INITIAL_SIZE: This number needs to start out as a
+// power of 2 given how it gets used. We double the segment array
+// when we overflow it, and use that fact that it's a power of 2 
+// to compute a fast modulus operation in IsFull.
+//
+// 32 segment array entries can accommodate 128k of data if segments
+// are 4k in size. That seems like a reasonable amount that will avoid
+// needing to grow the segment array.
+#define NS_SEGMENTARRAY_INITIAL_COUNT 32
+
+#endif // nsSegmentedBuffer_h__