74 lines
2.3 KiB
C++
74 lines
2.3 KiB
C++
// Copyright 2015 Google Inc.
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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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//
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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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//
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////////////////////////////////////////////////////////////////////////////////
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//
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// LRU cache decorator for binary_parse::PagedByteArray subclasses.
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#ifndef PIEX_BINARY_PARSE_CACHED_PAGED_BYTE_ARRAY_H_
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#define PIEX_BINARY_PARSE_CACHED_PAGED_BYTE_ARRAY_H_
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#include <mutex>
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#include <vector>
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#if !defined(WIN32_LEAN_AND_MEAN)
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#define WIN32_LEAN_AND_MEAN
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#endif
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#include "src/binary_parse/range_checked_byte_ptr.h"
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namespace piex {
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namespace binary_parse {
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class CachedPagedByteArray : public PagedByteArray {
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public:
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// Decorates 'paged_byte_array' with a LRU cache layer of the size
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// 'cache_size'.
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explicit CachedPagedByteArray(const PagedByteArray* paged_byte_array,
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size_t cache_size);
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virtual size_t length() const { return paged_byte_array_->length(); }
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virtual size_t pageSize() const { return paged_byte_array_->pageSize(); }
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virtual void getPage(size_t page_index, const unsigned char** begin,
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const unsigned char** end,
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PagedByteArray::PagePtr* page) const;
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private:
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struct CachedPage {
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size_t index;
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PagedByteArray::PagePtr page;
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const unsigned char* begin;
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const unsigned char* end;
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};
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// Disallow copy construction and assignment.
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CachedPagedByteArray(const CachedPagedByteArray&);
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void operator=(const CachedPagedByteArray&);
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// Gets the index of the page if it is in the cache and returns true, else
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// returns false.
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bool getFromCache(size_t page_index, size_t* cache_index) const;
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mutable std::mutex mutex_;
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const PagedByteArray* paged_byte_array_;
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const size_t cache_size_;
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mutable std::vector<CachedPage> cached_pages_;
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};
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} // namespace binary_parse
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} // namespace piex
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#endif // PIEX_BINARY_PARSE_CACHED_PAGED_BYTE_ARRAY_H_
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