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143 lines
4.4 KiB
C++
143 lines
4.4 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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*
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* The contents of this file are subject to the Netscape Public License
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* Version 1.0 (the "NPL"); you may not use this file except in
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* compliance with the NPL. You may obtain a copy of the NPL at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the NPL is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
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* for the specific language governing rights and limitations under the
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* NPL.
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*
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* The Initial Developer of this code under the NPL is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1998 Netscape Communications Corporation. All Rights
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* Reserved.
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*/
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#include "nsSegmentedBuffer.h"
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#include "nsCRT.h"
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#ifdef DEBUG
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#define DEBUG_MEMSET(addr, value, count) nsCRT::memset(addr, value, count)
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#else
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#define DEBUG_MEMSET(addr, value, count) /* nothing */
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#endif
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nsSegmentedBuffer::nsSegmentedBuffer(PRUint32 segmentSize, PRUint32 maxSize,
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nsIAllocator* allocator)
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: mSegmentSize(segmentSize), mMaxSize(maxSize),
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mSegAllocator(allocator), mSegmentArray(nsnull),
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mSegmentArrayCount(NS_SEGMENTARRAY_INITIAL_COUNT),
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mFirstSegmentIndex(0), mLastSegmentIndex(0)
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{
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if (mSegAllocator == nsnull) {
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mSegAllocator = nsAllocator::GetGlobalAllocator();
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}
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else {
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NS_ADDREF(mSegAllocator);
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}
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}
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nsSegmentedBuffer::~nsSegmentedBuffer()
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{
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Empty();
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NS_RELEASE(mSegAllocator);
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}
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char*
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nsSegmentedBuffer::AppendNewSegment()
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{
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if (mSegmentArray == nsnull) {
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PRUint32 bytes = mSegmentArrayCount * sizeof(char*);
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mSegmentArray = (char**)nsAllocator::Alloc(bytes);
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if (mSegmentArray == nsnull)
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return nsnull;
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DEBUG_MEMSET(mSegmentArray, 0, bytes);
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}
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if (IsFull()) {
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PRUint32 newArraySize = mSegmentArrayCount * 2;
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PRUint32 bytes = newArraySize * sizeof(char*);
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if (bytes > mMaxSize)
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return nsnull;
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char** newSegArray = (char**)nsAllocator::Realloc(mSegmentArray, bytes);
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if (newSegArray == nsnull)
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return nsnull;
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mSegmentArray = newSegArray;
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// copy wrapped content to new extension
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if (mFirstSegmentIndex > mLastSegmentIndex) {
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// deal with wrap around case
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nsCRT::memcpy(&mSegmentArray[mSegmentArrayCount],
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mSegmentArray,
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mLastSegmentIndex * sizeof(char*));
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DEBUG_MEMSET(mSegmentArray, 0, mLastSegmentIndex * sizeof(char*));
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mLastSegmentIndex += mSegmentArrayCount;
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DEBUG_MEMSET(&mSegmentArray[mLastSegmentIndex],
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0, (newArraySize - mLastSegmentIndex) * sizeof(char*));
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}
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mSegmentArrayCount = newArraySize;
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}
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char* seg = (char*)mSegAllocator->Alloc(mSegmentSize);
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if (seg == nsnull) {
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return nsnull;
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}
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mSegmentArray[mLastSegmentIndex] = seg;
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mLastSegmentIndex = ModSegArraySize(mLastSegmentIndex + 1);
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return seg;
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}
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PRBool
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nsSegmentedBuffer::DeleteFirstSegment()
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{
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NS_ASSERTION(mSegmentArray[mFirstSegmentIndex] != nsnull, "deleting bad segment");
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(void)mSegAllocator->Free(mSegmentArray[mFirstSegmentIndex]);
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mSegmentArray[mFirstSegmentIndex] = nsnull;
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PRInt32 last = ModSegArraySize(mLastSegmentIndex - 1);
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if (mFirstSegmentIndex == last) {
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mLastSegmentIndex = last;
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return PR_TRUE;
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}
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else {
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mFirstSegmentIndex = ModSegArraySize(mFirstSegmentIndex + 1);
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return PR_FALSE;
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}
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}
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void
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nsSegmentedBuffer::Empty()
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{
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if (mSegmentArray) {
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for (PRUint32 i = 0; i < mSegmentArrayCount; i++) {
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if (mSegmentArray[i])
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mSegAllocator->Free(mSegmentArray[i]);
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}
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nsAllocator::Free(mSegmentArray);
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mSegmentArray = nsnull;
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}
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mSegmentArrayCount = NS_SEGMENTARRAY_INITIAL_COUNT;
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}
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#ifdef DEBUG
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NS_COM void
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TestSegmentedBuffer()
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{
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nsSegmentedBuffer* mgr = new nsSegmentedBuffer(4, 8);
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NS_ASSERTION(mgr, "out of memory");
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mgr->AppendNewSegment();
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mgr->AppendNewSegment();
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mgr->AppendNewSegment();
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mgr->DeleteFirstSegment();
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mgr->DeleteFirstSegment();
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mgr->AppendNewSegment();
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mgr->AppendNewSegment();
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mgr->AppendNewSegment();
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mgr->DeleteFirstSegment();
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delete mgr;
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}
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#endif
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////////////////////////////////////////////////////////////////////////////////
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