1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/io/nsSegmentedBuffer.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,167 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include "nsSegmentedBuffer.h"
1.10 +#include "nsMemory.h"
1.11 +
1.12 +nsresult
1.13 +nsSegmentedBuffer::Init(uint32_t segmentSize, uint32_t maxSize)
1.14 +{
1.15 + if (mSegmentArrayCount != 0)
1.16 + return NS_ERROR_FAILURE; // initialized more than once
1.17 + mSegmentSize = segmentSize;
1.18 + mMaxSize = maxSize;
1.19 +#if 0 // testing...
1.20 + mSegmentArrayCount = 2;
1.21 +#else
1.22 + mSegmentArrayCount = NS_SEGMENTARRAY_INITIAL_COUNT;
1.23 +#endif
1.24 + return NS_OK;
1.25 +}
1.26 +
1.27 +char*
1.28 +nsSegmentedBuffer::AppendNewSegment()
1.29 +{
1.30 + if (GetSize() >= mMaxSize)
1.31 + return nullptr;
1.32 +
1.33 + if (mSegmentArray == nullptr) {
1.34 + uint32_t bytes = mSegmentArrayCount * sizeof(char*);
1.35 + mSegmentArray = (char**)nsMemory::Alloc(bytes);
1.36 + if (mSegmentArray == nullptr)
1.37 + return nullptr;
1.38 + memset(mSegmentArray, 0, bytes);
1.39 + }
1.40 +
1.41 + if (IsFull()) {
1.42 + uint32_t newArraySize = mSegmentArrayCount * 2;
1.43 + uint32_t bytes = newArraySize * sizeof(char*);
1.44 + char** newSegArray = (char**)nsMemory::Realloc(mSegmentArray, bytes);
1.45 + if (newSegArray == nullptr)
1.46 + return nullptr;
1.47 + mSegmentArray = newSegArray;
1.48 + // copy wrapped content to new extension
1.49 + if (mFirstSegmentIndex > mLastSegmentIndex) {
1.50 + // deal with wrap around case
1.51 + memcpy(&mSegmentArray[mSegmentArrayCount],
1.52 + mSegmentArray,
1.53 + mLastSegmentIndex * sizeof(char*));
1.54 + memset(mSegmentArray, 0, mLastSegmentIndex * sizeof(char*));
1.55 + mLastSegmentIndex += mSegmentArrayCount;
1.56 + memset(&mSegmentArray[mLastSegmentIndex], 0,
1.57 + (newArraySize - mLastSegmentIndex) * sizeof(char*));
1.58 + }
1.59 + else {
1.60 + memset(&mSegmentArray[mLastSegmentIndex], 0,
1.61 + (newArraySize - mLastSegmentIndex) * sizeof(char*));
1.62 + }
1.63 + mSegmentArrayCount = newArraySize;
1.64 + }
1.65 +
1.66 + char* seg = (char*)moz_malloc(mSegmentSize);
1.67 + if (seg == nullptr) {
1.68 + return nullptr;
1.69 + }
1.70 + mSegmentArray[mLastSegmentIndex] = seg;
1.71 + mLastSegmentIndex = ModSegArraySize(mLastSegmentIndex + 1);
1.72 + return seg;
1.73 +}
1.74 +
1.75 +bool
1.76 +nsSegmentedBuffer::DeleteFirstSegment()
1.77 +{
1.78 + NS_ASSERTION(mSegmentArray[mFirstSegmentIndex] != nullptr, "deleting bad segment");
1.79 + moz_free(mSegmentArray[mFirstSegmentIndex]);
1.80 + mSegmentArray[mFirstSegmentIndex] = nullptr;
1.81 + int32_t last = ModSegArraySize(mLastSegmentIndex - 1);
1.82 + if (mFirstSegmentIndex == last) {
1.83 + mLastSegmentIndex = last;
1.84 + return true;
1.85 + }
1.86 + else {
1.87 + mFirstSegmentIndex = ModSegArraySize(mFirstSegmentIndex + 1);
1.88 + return false;
1.89 + }
1.90 +}
1.91 +
1.92 +bool
1.93 +nsSegmentedBuffer::DeleteLastSegment()
1.94 +{
1.95 + int32_t last = ModSegArraySize(mLastSegmentIndex - 1);
1.96 + NS_ASSERTION(mSegmentArray[last] != nullptr, "deleting bad segment");
1.97 + moz_free(mSegmentArray[last]);
1.98 + mSegmentArray[last] = nullptr;
1.99 + mLastSegmentIndex = last;
1.100 + return (bool)(mLastSegmentIndex == mFirstSegmentIndex);
1.101 +}
1.102 +
1.103 +bool
1.104 +nsSegmentedBuffer::ReallocLastSegment(size_t newSize)
1.105 +{
1.106 + int32_t last = ModSegArraySize(mLastSegmentIndex - 1);
1.107 + NS_ASSERTION(mSegmentArray[last] != nullptr, "realloc'ing bad segment");
1.108 + char *newSegment =
1.109 + (char*)moz_realloc(mSegmentArray[last], newSize);
1.110 + if (newSegment) {
1.111 + mSegmentArray[last] = newSegment;
1.112 + return true;
1.113 + } else {
1.114 + return false;
1.115 + }
1.116 +}
1.117 +
1.118 +void
1.119 +nsSegmentedBuffer::Empty()
1.120 +{
1.121 + if (mSegmentArray) {
1.122 + for (uint32_t i = 0; i < mSegmentArrayCount; i++) {
1.123 + if (mSegmentArray[i])
1.124 + moz_free(mSegmentArray[i]);
1.125 + }
1.126 + nsMemory::Free(mSegmentArray);
1.127 + mSegmentArray = nullptr;
1.128 + }
1.129 + mSegmentArrayCount = NS_SEGMENTARRAY_INITIAL_COUNT;
1.130 + mFirstSegmentIndex = mLastSegmentIndex = 0;
1.131 +}
1.132 +
1.133 +#if 0
1.134 +void
1.135 +TestSegmentedBuffer()
1.136 +{
1.137 + nsSegmentedBuffer* buf = new nsSegmentedBuffer();
1.138 + NS_ASSERTION(buf, "out of memory");
1.139 + buf->Init(4, 16);
1.140 + char* seg;
1.141 + bool empty;
1.142 + seg = buf->AppendNewSegment();
1.143 + NS_ASSERTION(seg, "AppendNewSegment failed");
1.144 + seg = buf->AppendNewSegment();
1.145 + NS_ASSERTION(seg, "AppendNewSegment failed");
1.146 + seg = buf->AppendNewSegment();
1.147 + NS_ASSERTION(seg, "AppendNewSegment failed");
1.148 + empty = buf->DeleteFirstSegment();
1.149 + NS_ASSERTION(!empty, "DeleteFirstSegment failed");
1.150 + empty = buf->DeleteFirstSegment();
1.151 + NS_ASSERTION(!empty, "DeleteFirstSegment failed");
1.152 + seg = buf->AppendNewSegment();
1.153 + NS_ASSERTION(seg, "AppendNewSegment failed");
1.154 + seg = buf->AppendNewSegment();
1.155 + NS_ASSERTION(seg, "AppendNewSegment failed");
1.156 + seg = buf->AppendNewSegment();
1.157 + NS_ASSERTION(seg, "AppendNewSegment failed");
1.158 + empty = buf->DeleteFirstSegment();
1.159 + NS_ASSERTION(!empty, "DeleteFirstSegment failed");
1.160 + empty = buf->DeleteFirstSegment();
1.161 + NS_ASSERTION(!empty, "DeleteFirstSegment failed");
1.162 + empty = buf->DeleteFirstSegment();
1.163 + NS_ASSERTION(!empty, "DeleteFirstSegment failed");
1.164 + empty = buf->DeleteFirstSegment();
1.165 + NS_ASSERTION(empty, "DeleteFirstSegment failed");
1.166 + delete buf;
1.167 +}
1.168 +#endif
1.169 +
1.170 +////////////////////////////////////////////////////////////////////////////////
