mirror of
https://github.com/rn10950/RetroZilla.git
synced 2024-11-14 03:30:17 +01:00
126 lines
4.6 KiB
C++
126 lines
4.6 KiB
C++
/* -*- 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__
|