4463b11cad
Summary: Migrate names of properties from 'leveldb' prefix to 'rocksdb' prefix. Test Plan: make check Reviewers: emayanke, haobo Reviewed By: haobo CC: leveldb Differential Revision: https://reviews.facebook.net/D13311
131 lines
5.2 KiB
C++
131 lines
5.2 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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//
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// Endian-neutral encoding:
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// * Fixed-length numbers are encoded with least-significant byte first
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// * In addition we support variable length "varint" encoding
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// * Strings are encoded prefixed by their length in varint format
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#pragma once
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#include <stdint.h>
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#include <string.h>
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#include <string>
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#include "port/port.h"
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namespace rocksdb {
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// The maximum length of a varint in bytes for 32 and 64 bits respectively.
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const unsigned int kMaxVarint32Length = 5;
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const unsigned int kMaxVarint64Length = 10;
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// Standard Put... routines append to a string
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extern void PutFixed32(std::string* dst, uint32_t value);
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extern void PutFixed64(std::string* dst, uint64_t value);
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extern void PutVarint32(std::string* dst, uint32_t value);
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extern void PutVarint64(std::string* dst, uint64_t value);
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extern void PutLengthPrefixedSlice(std::string* dst, const Slice& value);
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// Standard Get... routines parse a value from the beginning of a Slice
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// and advance the slice past the parsed value.
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extern bool GetVarint32(Slice* input, uint32_t* value);
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extern bool GetVarint64(Slice* input, uint64_t* value);
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extern bool GetLengthPrefixedSlice(Slice* input, Slice* result);
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extern Slice GetLengthPrefixedSlice(const char* data);
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// Pointer-based variants of GetVarint... These either store a value
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// in *v and return a pointer just past the parsed value, or return
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// nullptr on error. These routines only look at bytes in the range
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// [p..limit-1]
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extern const char* GetVarint32Ptr(const char* p,const char* limit, uint32_t* v);
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extern const char* GetVarint64Ptr(const char* p,const char* limit, uint64_t* v);
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// Returns the length of the varint32 or varint64 encoding of "v"
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extern int VarintLength(uint64_t v);
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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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extern void EncodeFixed32(char* dst, uint32_t value);
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extern void EncodeFixed64(char* dst, uint64_t value);
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// Lower-level versions of Put... that write directly into a character buffer
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// and return a pointer just past the last byte written.
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// REQUIRES: dst has enough space for the value being written
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extern char* EncodeVarint32(char* dst, uint32_t value);
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extern char* EncodeVarint64(char* dst, uint64_t value);
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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 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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}
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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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// Internal routine for use by fallback path of GetVarint32Ptr
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extern const char* GetVarint32PtrFallback(const char* p,
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const char* limit,
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uint32_t* value);
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inline const char* GetVarint32Ptr(const char* p,
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const char* limit,
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uint32_t* value) {
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if (p < limit) {
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uint32_t result = *(reinterpret_cast<const unsigned char*>(p));
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if ((result & 128) == 0) {
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*value = result;
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return p + 1;
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}
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}
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return GetVarint32PtrFallback(p, limit, value);
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}
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// Writes an unsigned integer with bits number of bits with its least
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// significant bit at offset.
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// Bits are numbered from 0 to 7 in the first byte, 8 to 15 in the second and
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// so on.
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// value is truncated to the bits number of least significant bits.
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// REQUIRES: (offset+bits+7)/8 <= dstlen
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// REQUIRES: bits <= 64
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extern void BitStreamPutInt(char* dst, size_t dstlen, size_t offset,
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uint32_t bits, uint64_t value);
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// Reads an unsigned integer with bits number of bits with its least
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// significant bit at offset.
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// Bits are numbered in the same way as ByteStreamPutInt().
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// REQUIRES: (offset+bits+7)/8 <= srclen
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// REQUIRES: bits <= 64
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extern uint64_t BitStreamGetInt(const char* src, size_t srclen, size_t offset,
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uint32_t bits);
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// Convenience functions
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extern void BitStreamPutInt(std::string* dst, size_t offset, uint32_t bits,
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uint64_t value);
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extern uint64_t BitStreamGetInt(const std::string* src, size_t offset,
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uint32_t bits);
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extern uint64_t BitStreamGetInt(const Slice* src, size_t offset,
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uint32_t bits);
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} // namespace rocksdb
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