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arangodb/lib/Basics/StringHeap.cpp

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2.5 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
////////////////////////////////////////////////////////////////////////////////
#include "StringHeap.h"
#include "Basics/Exceptions.h"
#include "Basics/debugging.h"
using namespace arangodb;
/// @brief create a StringHeap instance
StringHeap::StringHeap(size_t blockSize)
: _blocks(), _blockSize(blockSize), _current(nullptr), _end(nullptr) {
TRI_ASSERT(blockSize >= 64);
}
StringHeap::~StringHeap() {
for (auto& it : _blocks) {
delete[] it;
}
}
/// @brief register a string
arangodb::velocypack::StringRef StringHeap::registerString(char const* ptr, size_t length) {
if (_current == nullptr || (_current + length + 1 > _end)) {
allocateBlock();
}
TRI_ASSERT(!_blocks.empty());
TRI_ASSERT(_current != nullptr);
TRI_ASSERT(_end != nullptr);
TRI_ASSERT(_current + length + 1 <= _end);
char* position = _current;
memcpy(static_cast<void*>(position), ptr, length);
// null-terminate the string
_current[length] = '\0';
_current += length + 1;
return arangodb::velocypack::StringRef(position, length);
}
void StringHeap::clear() {
_current = nullptr;
_end = nullptr;
for (auto& it : _blocks) {
delete[] it;
}
_blocks.clear();
}
void StringHeap::merge(StringHeap&& heap) {
_blocks.reserve(_blocks.size() + heap._blocks.size());
_blocks.insert(_blocks.end(), heap._blocks.begin(), heap._blocks.end());
heap._blocks.clear();
heap._current = nullptr;
}
/// @brief allocate a new block of memory
void StringHeap::allocateBlock() {
char* buffer = new char[_blockSize];
try {
_blocks.emplace_back(buffer);
_current = buffer;
_end = _current + _blockSize;
} catch (...) {
delete[] buffer;
throw;
}
}