mirror of
https://github.com/google/leveldb.git
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36a5f8ed7f
- Replace raw slice comparison with a call to user comparator.
Added test for custom comparators.
- Fix end of namespace comments.
- Fixed bug in picking inputs for a level-0 compaction.
When finding overlapping files, the covered range may expand
as files are added to the input set. We now correctly expand
the range when this happens instead of continuing to use the
old range. For example, suppose L0 contains files with the
following ranges:
F1: a .. d
F2: c .. g
F3: f .. j
and the initial compaction target is F3. We used to search
for range f..j which yielded {F2,F3}. However we now expand
the range as soon as another file is added. In this case,
when F2 is added, we expand the range to c..j and restart the
search. That picks up file F1 as well.
This change fixes a bug related to deleted keys showing up
incorrectly after a compaction as described in Issue 44.
(Sync with upstream @25072954)
105 lines
4.0 KiB
C++
105 lines
4.0 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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#ifndef STORAGE_LEVELDB_UTIL_CODING_H_
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#define STORAGE_LEVELDB_UTIL_CODING_H_
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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 "leveldb/slice.h"
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#include "port/port.h"
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namespace leveldb {
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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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// 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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// NULL 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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} // namespace leveldb
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#endif // STORAGE_LEVELDB_UTIL_CODING_H_
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