100 lines
2.9 KiB
C++
100 lines
2.9 KiB
C++
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// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "nvs_item_hash_list.hpp"
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namespace nvs
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{
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HashList::~HashList()
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{
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for (auto it = mBlockList.begin(); it != mBlockList.end();) {
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auto tmp = it;
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++it;
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mBlockList.erase(tmp);
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delete static_cast<HashListBlock*>(tmp);
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}
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}
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HashList::HashListBlock::HashListBlock()
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{
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static_assert(sizeof(HashListBlock) == HashListBlock::BYTE_SIZE,
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"cache block size calculation incorrect");
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}
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void HashList::insert(const Item& item, size_t index)
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{
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const uint32_t hash_24 = item.calculateCrc32WithoutValue() & 0xffffff;
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// add entry to the end of last block if possible
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if (mBlockList.size()) {
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auto& block = mBlockList.back();
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if (block.mCount < HashListBlock::ENTRY_COUNT) {
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block.mNodes[block.mCount++] = HashListNode(hash_24, index);
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return;
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}
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}
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// if the above failed, create a new block and add entry to it
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HashListBlock* newBlock = new HashListBlock;
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mBlockList.push_back(newBlock);
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newBlock->mNodes[0] = HashListNode(hash_24, index);
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newBlock->mCount++;
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}
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void HashList::erase(size_t index)
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{
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for (auto it = std::begin(mBlockList); it != std::end(mBlockList);)
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{
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bool haveEntries = false;
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for (size_t i = 0; i < it->mCount; ++i) {
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if (it->mNodes[i].mIndex == index) {
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it->mNodes[i].mIndex = 0xff;
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return;
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}
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if (it->mNodes[i].mIndex != 0xff) {
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haveEntries = true;
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}
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}
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if (!haveEntries) {
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auto tmp = it;
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++it;
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mBlockList.erase(tmp);
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delete static_cast<HashListBlock*>(tmp);
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}
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else {
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++it;
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}
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}
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assert(false && "item should have been present in cache");
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}
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size_t HashList::find(size_t start, const Item& item)
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{
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const uint32_t hash_24 = item.calculateCrc32WithoutValue() & 0xffffff;
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for (auto it = std::begin(mBlockList); it != std::end(mBlockList); ++it)
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{
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for (size_t index = 0; index < it->mCount; ++index) {
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HashListNode& e = it->mNodes[index];
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if (e.mIndex >= start &&
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e.mHash == hash_24 &&
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e.mIndex != 0xff) {
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return e.mIndex;
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}
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}
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}
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return SIZE_MAX;
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}
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} // namespace nvs
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