pjs/xpcom/ds/nsFragmentedString.cpp

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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 XPCOM.
*
* 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.
*
* Original Author:
* Scott Collins <scc@mozilla.org>
*
* Contributor(s):
*/
#include "nsFragmentedString.h"
const PRUnichar*
nsFragmentedString::GetReadableFragment( nsReadableFragment<PRUnichar>& aFragment, nsFragmentRequest aRequest, PRUint32 aOffset ) const
{
const nsSharedBufferList::Buffer* buffer = 0;
switch ( aRequest )
{
case kPrevFragment:
buffer = NS_STATIC_CAST(const nsSharedBufferList::Buffer*, aFragment.mFragmentIdentifier)->mPrev;
break;
case kFirstFragment:
buffer = mBufferList.GetFirstBuffer();
break;
case kLastFragment:
buffer = mBufferList.GetLastBuffer();
break;
case kNextFragment:
buffer = NS_STATIC_CAST(const nsSharedBufferList::Buffer*, aFragment.mFragmentIdentifier)->mNext;
break;
case kFragmentAt:
// ...work...
break;
}
if ( buffer )
{
aFragment.mStart = buffer->DataStart();
aFragment.mEnd = buffer->DataEnd();
aFragment.mFragmentIdentifier = buffer;
return aFragment.mStart + aOffset;
}
return 0;
}
PRUnichar*
nsFragmentedString::GetWritableFragment( nsWritableFragment<PRUnichar>& aFragment, nsFragmentRequest aRequest, PRUint32 aOffset )
{
nsSharedBufferList::Buffer* buffer = 0;
switch ( aRequest )
{
case kPrevFragment:
buffer = NS_STATIC_CAST(nsSharedBufferList::Buffer*, aFragment.mFragmentIdentifier)->mPrev;
break;
case kFirstFragment:
buffer = mBufferList.GetFirstBuffer();
break;
case kLastFragment:
buffer = mBufferList.GetLastBuffer();
break;
case kNextFragment:
buffer = NS_STATIC_CAST(nsSharedBufferList::Buffer*, aFragment.mFragmentIdentifier)->mNext;
break;
case kFragmentAt:
// ...work...
break;
}
if ( buffer )
{
aFragment.mStart = buffer->DataStart();
aFragment.mEnd = buffer->DataEnd();
aFragment.mFragmentIdentifier = buffer;
return aFragment.mStart + aOffset;
}
return 0;
}
/**
* ...
*/
PRUint32
nsFragmentedString::Length() const
{
return PRUint32(mBufferList.GetDataLength());
}
/**
* |SetLength|
*/
void
nsFragmentedString::SetLength( PRUint32 aNewLength )
{
// according to the current interpretation of |SetLength|,
// cut off characters from the end, or else add unitialized space to fill
if ( aNewLength < mBufferList.GetDataLength() )
{
// if ( aNewLength )
mBufferList.DiscardSuffix(mBufferList.GetDataLength()-aNewLength);
// else
// mBufferList.DestroyBuffers();
}
// temporarily... eliminate as soon as our munging routines don't need this form of |SetLength|
else if ( aNewLength > mBufferList.GetDataLength() )
{
size_t empty_space_to_add = aNewLength - mBufferList.GetDataLength();
nsSharedBufferList::Buffer* new_buffer = nsSharedBufferList::NewSingleAllocationBuffer(0, 0, empty_space_to_add);
new_buffer->DataEnd(new_buffer->DataStart()+empty_space_to_add);
mBufferList.LinkBuffer(mBufferList.GetLastBuffer(), new_buffer, 0);
}
}
#if 0
/**
* |SetCapacity|.
*
* If a client tries to increase the capacity of multi-fragment string, perhaps a single
* empty fragment of the appropriate size should be appended.
*/
void
nsFragmentedString::SetCapacity( PRUint32 aNewCapacity )
{
if ( !aNewCapacity )
{
// |SetCapacity(0)| is special and means ``release all storage''.
}
else if ( aNewCapacity > ... )
{
}
}
#endif