mirror of
https://github.com/mozilla/gecko-dev.git
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170 lines
4.9 KiB
C++
170 lines
4.9 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsSegmentedBuffer.h"
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#include "nsMemory.h"
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nsresult
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nsSegmentedBuffer::Init(uint32_t aSegmentSize, uint32_t aMaxSize)
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{
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if (mSegmentArrayCount != 0) {
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return NS_ERROR_FAILURE; // initialized more than once
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}
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mSegmentSize = aSegmentSize;
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mMaxSize = aMaxSize;
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#if 0 // testing...
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mSegmentArrayCount = 2;
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#else
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mSegmentArrayCount = NS_SEGMENTARRAY_INITIAL_COUNT;
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#endif
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return NS_OK;
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}
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char*
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nsSegmentedBuffer::AppendNewSegment()
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{
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if (GetSize() >= mMaxSize) {
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return nullptr;
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}
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if (!mSegmentArray) {
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uint32_t bytes = mSegmentArrayCount * sizeof(char*);
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mSegmentArray = (char**)moz_xmalloc(bytes);
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if (!mSegmentArray) {
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return nullptr;
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}
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memset(mSegmentArray, 0, bytes);
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}
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if (IsFull()) {
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uint32_t newArraySize = mSegmentArrayCount * 2;
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uint32_t bytes = newArraySize * sizeof(char*);
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char** newSegArray = (char**)moz_xrealloc(mSegmentArray, bytes);
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if (!newSegArray) {
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return nullptr;
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}
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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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memcpy(&mSegmentArray[mSegmentArrayCount],
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mSegmentArray,
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mLastSegmentIndex * sizeof(char*));
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memset(mSegmentArray, 0, mLastSegmentIndex * sizeof(char*));
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mLastSegmentIndex += mSegmentArrayCount;
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memset(&mSegmentArray[mLastSegmentIndex], 0,
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(newArraySize - mLastSegmentIndex) * sizeof(char*));
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} else {
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memset(&mSegmentArray[mLastSegmentIndex], 0,
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(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*)malloc(mSegmentSize);
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if (!seg) {
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return nullptr;
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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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bool
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nsSegmentedBuffer::DeleteFirstSegment()
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{
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NS_ASSERTION(mSegmentArray[mFirstSegmentIndex] != nullptr, "deleting bad segment");
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free(mSegmentArray[mFirstSegmentIndex]);
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mSegmentArray[mFirstSegmentIndex] = nullptr;
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int32_t last = ModSegArraySize(mLastSegmentIndex - 1);
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if (mFirstSegmentIndex == last) {
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mLastSegmentIndex = last;
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return true;
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} else {
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mFirstSegmentIndex = ModSegArraySize(mFirstSegmentIndex + 1);
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return false;
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}
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}
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bool
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nsSegmentedBuffer::DeleteLastSegment()
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{
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int32_t last = ModSegArraySize(mLastSegmentIndex - 1);
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NS_ASSERTION(mSegmentArray[last] != nullptr, "deleting bad segment");
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free(mSegmentArray[last]);
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mSegmentArray[last] = nullptr;
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mLastSegmentIndex = last;
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return (bool)(mLastSegmentIndex == mFirstSegmentIndex);
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}
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bool
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nsSegmentedBuffer::ReallocLastSegment(size_t aNewSize)
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{
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int32_t last = ModSegArraySize(mLastSegmentIndex - 1);
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NS_ASSERTION(mSegmentArray[last] != nullptr, "realloc'ing bad segment");
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char* newSegment = (char*)realloc(mSegmentArray[last], aNewSize);
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if (newSegment) {
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mSegmentArray[last] = newSegment;
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return true;
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}
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return false;
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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 (uint32_t i = 0; i < mSegmentArrayCount; i++) {
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if (mSegmentArray[i]) {
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free(mSegmentArray[i]);
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}
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}
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free(mSegmentArray);
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mSegmentArray = nullptr;
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}
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mSegmentArrayCount = NS_SEGMENTARRAY_INITIAL_COUNT;
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mFirstSegmentIndex = mLastSegmentIndex = 0;
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}
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#if 0
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void
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TestSegmentedBuffer()
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{
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nsSegmentedBuffer* buf = new nsSegmentedBuffer();
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NS_ASSERTION(buf, "out of memory");
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buf->Init(4, 16);
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char* seg;
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bool empty;
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seg = buf->AppendNewSegment();
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NS_ASSERTION(seg, "AppendNewSegment failed");
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seg = buf->AppendNewSegment();
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NS_ASSERTION(seg, "AppendNewSegment failed");
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seg = buf->AppendNewSegment();
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NS_ASSERTION(seg, "AppendNewSegment failed");
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empty = buf->DeleteFirstSegment();
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NS_ASSERTION(!empty, "DeleteFirstSegment failed");
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empty = buf->DeleteFirstSegment();
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NS_ASSERTION(!empty, "DeleteFirstSegment failed");
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seg = buf->AppendNewSegment();
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NS_ASSERTION(seg, "AppendNewSegment failed");
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seg = buf->AppendNewSegment();
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NS_ASSERTION(seg, "AppendNewSegment failed");
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seg = buf->AppendNewSegment();
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NS_ASSERTION(seg, "AppendNewSegment failed");
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empty = buf->DeleteFirstSegment();
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NS_ASSERTION(!empty, "DeleteFirstSegment failed");
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empty = buf->DeleteFirstSegment();
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NS_ASSERTION(!empty, "DeleteFirstSegment failed");
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empty = buf->DeleteFirstSegment();
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NS_ASSERTION(!empty, "DeleteFirstSegment failed");
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empty = buf->DeleteFirstSegment();
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NS_ASSERTION(empty, "DeleteFirstSegment failed");
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delete buf;
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}
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#endif
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////////////////////////////////////////////////////////////////////////////////
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