mirror of https://gitee.com/bigwinds/arangodb
139 lines
4.1 KiB
C++
139 lines
4.1 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2018 ArangoDB GmbH, Cologne, Germany
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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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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Simon Grätzer
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGO_ROCKSDB_ROCKSDB_FORMAT_H
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#define ARANGO_ROCKSDB_ROCKSDB_FORMAT_H 1
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#include "Basics/Common.h"
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#include "Basics/Endian.h"
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#include "RocksDBEngine/RocksDBTypes.h"
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#undef TRI_USE_FAST_UNALIGNED_DATA_ACCESS
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#ifdef TRI_UNALIGNED_ACCESS
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#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
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#define TRI_USE_FAST_UNALIGNED_DATA_ACCESS
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#endif
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#endif
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namespace arangodb {
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namespace rocksutils {
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/* function pointers to serialization implementation */
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extern uint16_t (*uint16FromPersistent)(char const* p);
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extern uint32_t (*uint32FromPersistent)(char const* p);
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extern uint64_t (*uint64FromPersistent)(char const* p);
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extern void (*uint16ToPersistent)(std::string& p, uint16_t value);
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extern void (*uint32ToPersistent)(std::string& p, uint32_t value);
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extern void (*uint64ToPersistent)(std::string& p, uint64_t value);
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/// Enable litte endian or big-endian key formats
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void setRocksDBKeyFormatEndianess(RocksDBEndianness);
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inline uint64_t doubleToInt(double d) {
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uint64_t i;
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std::memcpy(&i, &d, sizeof(i));
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return i;
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}
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inline double intToDouble(uint64_t i) {
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double d;
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std::memcpy(&d, &i, sizeof(i));
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return d;
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}
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template<typename T>
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inline T uintFromPersistentLittleEndian(char const* p) {
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static_assert(std::is_unsigned<T>::value, "type must be unsigned");
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#ifdef TRI_USE_FAST_UNALIGNED_DATA_ACCESS
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static_assert(basics::isLittleEndian(), "");
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return *reinterpret_cast<T const*>(p);
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#else
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T value = 0;
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T x = 0;
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uint8_t const* ptr = reinterpret_cast<uint8_t const*>(p);
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uint8_t const* end = ptr + sizeof(T);
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do {
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value += static_cast<T>(*ptr++) << x;
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x += 8;
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} while (ptr < end);
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return value;
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#endif
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}
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template<typename T>
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inline T uintFromPersistentBigEndian(char const* p) {
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//return basics::bigToHost(uintFromPersistentLittleEndian<T>(p));
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static_assert(std::is_unsigned<T>::value, "type must be unsigned");
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#ifdef TRI_USE_FAST_UNALIGNED_DATA_ACCESS
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return basics::bigToHost(*reinterpret_cast<T const*>(p));
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#else
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T value = 0;
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T x = sizeof(T) * 8;
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uint8_t const* ptr = reinterpret_cast<uint8_t const*>(p);
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uint8_t const* end = ptr + sizeof(T);
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do {
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x -= 8;
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value += static_cast<T>(*ptr++) << x;
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} while (ptr < end);
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TRI_ASSERT(x == 0);
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return value;
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#endif
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}
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template<typename T>
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inline void uintToPersistentLittleEndian(std::string& p, T value) {
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static_assert(std::is_unsigned<T>::value, "type must be unsigned");
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#ifdef TRI_USE_FAST_UNALIGNED_DATA_ACCESS
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static_assert(basics::isLittleEndian(), "");
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p.append(reinterpret_cast<const char*>(&value), sizeof(T));
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#else
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size_t len = 0;
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do {
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p.push_back(static_cast<char>(value & 0xffU));
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value >>= 8;
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} while (++len < sizeof(T));
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#endif
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}
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template<typename T>
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inline void uintToPersistentBigEndian(std::string& p, T value) {
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//uintToPersistentLittleEndian<T>(p, basics::hostToBig(value));
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static_assert(std::is_unsigned<T>::value, "type must be unsigned");
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#ifdef TRI_USE_FAST_UNALIGNED_DATA_ACCESS
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value = basics::hostToBig(value);
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p.append(reinterpret_cast<const char*>(&value), sizeof(T));
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#else
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size_t len = sizeof(T) * 8;
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do {
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len -= 8;
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p.push_back(static_cast<char>((value >> len) & 0xFF));
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} while (len != 0);
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#endif
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}
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} // namespace rocksutils
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} // namespace arangodb
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#endif
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