tomFlowee
c63519fa47
The leveldb and univalue 3rd party libraries are not installed and not needed by anyone outside of the Hub. So move them there, making it easier for 3rd party usage.
69 lines
1.8 KiB
C++
69 lines
1.8 KiB
C++
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#ifndef STORAGE_LEVELDB_UTIL_ARENA_H_
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#define STORAGE_LEVELDB_UTIL_ARENA_H_
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#include <vector>
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#include <assert.h>
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#include <stddef.h>
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#include <stdint.h>
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namespace leveldb {
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class Arena {
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public:
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Arena();
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~Arena();
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// Return a pointer to a newly allocated memory block of "bytes" bytes.
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char* Allocate(size_t bytes);
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// Allocate memory with the normal alignment guarantees provided by malloc
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char* AllocateAligned(size_t bytes);
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// Returns an estimate of the total memory usage of data allocated
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// by the arena (including space allocated but not yet used for user
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// allocations).
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size_t MemoryUsage() const {
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return blocks_memory_ + blocks_.capacity() * sizeof(char*);
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}
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private:
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char* AllocateFallback(size_t bytes);
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char* AllocateNewBlock(size_t block_bytes);
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// Allocation state
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char* alloc_ptr_;
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size_t alloc_bytes_remaining_;
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// Array of new[] allocated memory blocks
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std::vector<char*> blocks_;
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// Bytes of memory in blocks allocated so far
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size_t blocks_memory_;
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// No copying allowed
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Arena(const Arena&);
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void operator=(const Arena&);
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};
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inline char* Arena::Allocate(size_t bytes) {
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// The semantics of what to return are a bit messy if we allow
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// 0-byte allocations, so we disallow them here (we don't need
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// them for our internal use).
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assert(bytes > 0);
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if (bytes <= alloc_bytes_remaining_) {
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char* result = alloc_ptr_;
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alloc_ptr_ += bytes;
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alloc_bytes_remaining_ -= bytes;
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return result;
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}
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return AllocateFallback(bytes);
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}
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} // namespace leveldb
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#endif // STORAGE_LEVELDB_UTIL_ARENA_H_
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