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