pjs/xpcom/ds/nsSharedBufferList.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
* 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 strings.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 2000 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
* Scott Collins <scc@mozilla.org> (original author)
*
*/
#ifndef nsSharedBufferList_h___
#define nsSharedBufferList_h___
#ifndef nsBufferHandle_h___
#include "nsBufferHandle.h"
// for |nsSharedBufferHandle|
#endif
#ifndef nscore_h___
#include "nscore.h"
// for |PRUnichar|
#endif
#ifndef nsAReadableString_h___
#include "nsAReadableString.h"
// for |nsReadingIterator|
#endif
/**
* This class forms the basis for several multi-fragment string classes, in
* particular: |nsFragmentedString| (though not yet), and |nsSlidingString|/|nsSlidingSubstring|.
*
* This class is not templated. It is provided only for |PRUnichar|-based strings.
* If we turn out to have a need for multi-fragment ASCII strings, then perhaps we'll templatize
* or else duplicate this class.
*/
class nsSharedBufferList
{
public:
class Buffer
: public nsFlexBufferHandle<PRUnichar>
{
public:
Buffer( PRUnichar* aDataStart, PRUnichar* aDataEnd, PRUnichar* aStorageStart, PRUnichar* aStorageEnd, PRBool aIsSingleAllocation=PR_FALSE )
: nsFlexBufferHandle<PRUnichar>(aDataStart, aDataEnd, aStorageStart, aStorageEnd)
{
if ( aIsSingleAllocation )
this->mFlags |= this->kIsSingleAllocationWithBuffer;
}
Buffer* mPrev;
Buffer* mNext;
private:
// pass-by-value is explicitly denied
Buffer( const Buffer& ); // NOT TO BE IMPLEMENTED
void operator=( const Buffer& ); // NOT TO BE IMPLEMENTED
};
struct Position
{
Buffer* mBuffer;
PRUnichar* mPosInBuffer;
Position() { }
Position( Buffer* aBuffer, PRUnichar* aPosInBuffer ) : mBuffer(aBuffer), mPosInBuffer(aPosInBuffer) { }
// Position( const Position& ); -- auto-generated copy-constructor OK
// Position& operator=( const Position& ); -- auto-generated copy-assignment OK
// ~Position(); -- auto-generated destructor OK
// iff |aIter| is a valid iterator into a |nsSharedBufferList|
explicit
Position( const nsReadingIterator<PRUnichar>& aIter )
: mBuffer( NS_CONST_CAST(Buffer*, NS_REINTERPRET_CAST(const Buffer*, aIter.fragment().mFragmentIdentifier)) ),
mPosInBuffer( NS_CONST_CAST(PRUnichar*, aIter.get()) )
{
// nothing else to do here
}
// iff |aIter| is a valid iterator into a |nsSharedBufferList|
Position&
operator=( const nsReadingIterator<PRUnichar>& aIter )
{
mBuffer = NS_CONST_CAST(Buffer*, NS_REINTERPRET_CAST(const Buffer*, aIter.fragment().mFragmentIdentifier));
mPosInBuffer = NS_CONST_CAST(PRUnichar*, aIter.get());
return *this;
}
void PointTo( Buffer* aBuffer, PRUnichar* aPosInBuffer ) { mBuffer=aBuffer; mPosInBuffer=aPosInBuffer; }
void PointBefore( Buffer* aBuffer ) { PointTo(aBuffer, aBuffer->DataStart()); }
void PointAfter( Buffer* aBuffer ) { PointTo(aBuffer, aBuffer->DataEnd()); }
// Position( const Position& ); -- automatically generated copy-constructor is OK
// Position& operator=( const Position& ); -- automatically generated copy-assignment operator is OK
};
public:
nsSharedBufferList( Buffer* aBuffer = 0 )
: mFirstBuffer(aBuffer),
mLastBuffer(aBuffer),
mTotalDataLength(0)
{
if ( aBuffer )
{
aBuffer->mPrev = aBuffer->mNext = 0;
mTotalDataLength = aBuffer->DataLength();
}
}
virtual ~nsSharedBufferList();
private:
// pass-by-value is explicitly denied
nsSharedBufferList( const nsSharedBufferList& ); // NOT TO BE IMPLEMENTED
void operator=( const nsSharedBufferList& ); // NOT TO BE IMPLEMENTED
public:
void LinkBuffer( Buffer*, Buffer*, Buffer* );
Buffer* UnlinkBuffer( Buffer* );
void SplitBuffer( const Position& );
static Buffer* NewSingleAllocationBuffer( const PRUnichar*, PRUint32, PRUint32 = 0 );
static Buffer* NewWrappingBuffer( PRUnichar*, PRUnichar*, PRUnichar* );
void DiscardSuffix( PRUint32 );
// need other discards: prefix, and by iterator or pointer or something
Buffer* GetFirstBuffer() { return mFirstBuffer; }
const Buffer* GetFirstBuffer() const { return mFirstBuffer; }
Buffer* GetLastBuffer() { return mLastBuffer; }
const Buffer* GetLastBuffer() const { return mLastBuffer; }
ptrdiff_t GetDataLength() const { return mTotalDataLength; }
protected:
void DestroyBuffers();
protected:
Buffer* mFirstBuffer;
Buffer* mLastBuffer;
ptrdiff_t mTotalDataLength;
};
#endif // !defined(nsSharedBufferList_h___)