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