fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
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101 lines
3.1 KiB
101 lines
3.1 KiB
// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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// Encoding independent of machine byte order:
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// * Fixed-length numbers are encoded with least-significant byte first
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// (little endian, native order on Intel and others)
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//
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// More functions in coding.h
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#pragma once
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#include <cstdint>
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#include <cstring>
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#include "port/port.h" // for port::kLittleEndian
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namespace ROCKSDB_NAMESPACE {
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// Lower-level versions of Put... that write directly into a character buffer
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// REQUIRES: dst has enough space for the value being written
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// -- Implementation of the functions declared above
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inline void EncodeFixed16(char* buf, uint16_t value) {
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if (port::kLittleEndian) {
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memcpy(buf, &value, sizeof(value));
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} else {
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buf[0] = value & 0xff;
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buf[1] = (value >> 8) & 0xff;
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}
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}
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inline void EncodeFixed32(char* buf, uint32_t value) {
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if (port::kLittleEndian) {
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memcpy(buf, &value, sizeof(value));
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} else {
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buf[0] = value & 0xff;
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buf[1] = (value >> 8) & 0xff;
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buf[2] = (value >> 16) & 0xff;
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buf[3] = (value >> 24) & 0xff;
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}
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}
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inline void EncodeFixed64(char* buf, uint64_t value) {
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if (port::kLittleEndian) {
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memcpy(buf, &value, sizeof(value));
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} else {
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buf[0] = value & 0xff;
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buf[1] = (value >> 8) & 0xff;
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buf[2] = (value >> 16) & 0xff;
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buf[3] = (value >> 24) & 0xff;
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buf[4] = (value >> 32) & 0xff;
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buf[5] = (value >> 40) & 0xff;
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buf[6] = (value >> 48) & 0xff;
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buf[7] = (value >> 56) & 0xff;
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}
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}
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// Lower-level versions of Get... that read directly from a character buffer
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// without any bounds checking.
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inline uint16_t DecodeFixed16(const char* ptr) {
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if (port::kLittleEndian) {
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// Load the raw bytes
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uint16_t result;
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memcpy(&result, ptr, sizeof(result)); // gcc optimizes this to a plain load
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return result;
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} else {
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return ((static_cast<uint16_t>(static_cast<unsigned char>(ptr[0]))) |
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(static_cast<uint16_t>(static_cast<unsigned char>(ptr[1])) << 8));
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}
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}
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inline uint32_t DecodeFixed32(const char* ptr) {
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if (port::kLittleEndian) {
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// Load the raw bytes
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uint32_t result;
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memcpy(&result, ptr, sizeof(result)); // gcc optimizes this to a plain load
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return result;
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} else {
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return ((static_cast<uint32_t>(static_cast<unsigned char>(ptr[0]))) |
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(static_cast<uint32_t>(static_cast<unsigned char>(ptr[1])) << 8) |
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(static_cast<uint32_t>(static_cast<unsigned char>(ptr[2])) << 16) |
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(static_cast<uint32_t>(static_cast<unsigned char>(ptr[3])) << 24));
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}
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}
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inline uint64_t DecodeFixed64(const char* ptr) {
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if (port::kLittleEndian) {
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// Load the raw bytes
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uint64_t result;
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memcpy(&result, ptr, sizeof(result)); // gcc optimizes this to a plain load
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return result;
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} else {
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uint64_t lo = DecodeFixed32(ptr);
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uint64_t hi = DecodeFixed32(ptr + 4);
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return (hi << 32) | lo;
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}
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}
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} // namespace ROCKSDB_NAMESPACE
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