зеркало из https://github.com/mozilla/gecko-dev.git
128 строки
3.8 KiB
C++
128 строки
3.8 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is auto buffer template.
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*
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* The Initial Developer of the Original Code is
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* Conrad Carlen <ccarlen@mac.com>.
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* Portions created by the Initial Developer are Copyright (C) 2004
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Jungshik Shin <jshin@mailaps.org>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef nsAutoBuffer_h__
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#define nsAutoBuffer_h__
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#ifndef nsMemory_h__
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#include "nsMemory.h"
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#endif
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/**
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* A buffer which will use stack space if the requested size will
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* fit in the stack buffer and allocate from the heap if not.
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*
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* Below is a usage example :
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*
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* typedef nsAutoBuffer<PRUnichar, 256> nsAutoUnicharBuffer;
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*
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* nsAutoUnicharBuffer buffer;
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*
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* if (!buffer.EnsureElemCapacity(initialLength))
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* return NS_ERROR_OUT_OF_MEMORY;
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*
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* PRUnichar *unicharPtr = buffer.get();
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*
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* // add PRUnichar's to the buffer pointed to by |unicharPtr| as long as
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* // the number of PRUnichar's is less than |intialLength|
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*
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* // increase the capacity
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* if (!buffer.AddElemCapacity(extraLength))
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* return NS_ERROR_OUT_OF_MEMORY
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*
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* unicharPtr = buffer.get() + initialLength;
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*
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* //continue to add PRUnichar's....
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*/
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template <class T, PRInt32 sz>
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class nsAutoBuffer
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{
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public:
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nsAutoBuffer() :
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mBufferPtr(mStackBuffer),
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mCurElemCapacity(sz)
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{
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}
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~nsAutoBuffer()
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{
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if (mBufferPtr != mStackBuffer)
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nsMemory::Free(mBufferPtr);
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}
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PRBool EnsureElemCapacity(PRInt32 inElemCapacity)
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{
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if (inElemCapacity <= mCurElemCapacity)
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return PR_TRUE;
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T* newBuffer;
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if (mBufferPtr != mStackBuffer)
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newBuffer = (T*)nsMemory::Realloc((void *)mBufferPtr, inElemCapacity * sizeof(T));
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else
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newBuffer = (T*)nsMemory::Alloc(inElemCapacity * sizeof(T));
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if (!newBuffer)
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return PR_FALSE;
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if (mBufferPtr != mStackBuffer)
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nsMemory::Free(mBufferPtr);
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mBufferPtr = newBuffer;
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mCurElemCapacity = inElemCapacity;
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return PR_TRUE;
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}
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PRBool AddElemCapacity(PRInt32 inElemCapacity)
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{
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return EnsureElemCapacity(mCurElemCapacity + inElemCapacity);
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}
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T* get() const { return mBufferPtr; }
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PRInt32 GetElemCapacity() const { return mCurElemCapacity; }
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protected:
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T *mBufferPtr;
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T mStackBuffer[sz];
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PRInt32 mCurElemCapacity;
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};
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#endif // nsAutoBuffer_h__
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