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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** 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 auto buffer template.
*
* The Initial Developer of the Original Code is
* Conrad Carlen <ccarlen@mac.com>.
* Portions created by the Initial Developer are Copyright (C) 2004
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Jungshik Shin <jshin@mailaps.org>
*
* 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 ***** */
#ifndef nsAutoBuffer_h__
#define nsAutoBuffer_h__
#ifndef nsMemory_h__
#include "nsMemory.h"
#endif
/**
* A buffer which will use stack space if the requested size will
* fit in the stack buffer and allocate from the heap if not.
*
* Below is a usage example :
*
* typedef nsAutoBuffer<PRUnichar, 256> nsAutoUnicharBuffer;
*
* nsAutoUnicharBuffer buffer;
*
* if (!buffer.EnsureElemCapacity(initialLength))
* return NS_ERROR_OUT_OF_MEMORY;
*
* PRUnichar *unicharPtr = buffer.get();
*
* // add PRUnichar's to the buffer pointed to by |unicharPtr| as long as
* // the number of PRUnichar's is less than |intialLength|
*
* // increase the capacity
* if (!buffer.AddElemCapacity(extraLength))
* return NS_ERROR_OUT_OF_MEMORY
*
* unicharPtr = buffer.get() + initialLength;
*
* //continue to add PRUnichar's....
*/
template <class T, PRInt32 sz>
class nsAutoBuffer
{
public:
nsAutoBuffer() :
mBufferPtr(mStackBuffer),
mCurElemCapacity(sz)
{
}
~nsAutoBuffer()
{
if (mBufferPtr != mStackBuffer)
nsMemory::Free(mBufferPtr);
}
PRBool EnsureElemCapacity(PRInt32 inElemCapacity)
{
if (inElemCapacity <= mCurElemCapacity)
return PR_TRUE;
T* newBuffer;
if (mBufferPtr != mStackBuffer)
newBuffer = (T*)nsMemory::Realloc((void *)mBufferPtr, inElemCapacity * sizeof(T));
else
newBuffer = (T*)nsMemory::Alloc(inElemCapacity * sizeof(T));
if (!newBuffer)
return PR_FALSE;
if (mBufferPtr != mStackBuffer)
nsMemory::Free(mBufferPtr);
mBufferPtr = newBuffer;
mCurElemCapacity = inElemCapacity;
return PR_TRUE;
}
PRBool AddElemCapacity(PRInt32 inElemCapacity)
{
return EnsureElemCapacity(mCurElemCapacity + inElemCapacity);
}
T* get() const { return mBufferPtr; }
PRInt32 GetElemCapacity() const { return mCurElemCapacity; }
protected:
T *mBufferPtr;
T mStackBuffer[sz];
PRInt32 mCurElemCapacity;
};
#endif // nsAutoBuffer_h__
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