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adae78ea99
ae6c262 Merge branch 'leveldb' into ripple-fork 28fa222 Looks like a bit more delay is needed to smooth the latency. a18f3e6 Tidy up JobQueue, add ripple_core module ab82e57 Release leveldb 1.12 02c6259 Release leveldb 1.11 5bbb544 Rate limit compactions with a 25ms pause after each complete file. 8c29c47 LevelDB issue 178 fix: cannot resize a level 0 compaction set 18b245c Added GNU/kFreeBSD kernel name (TARGET_OS) 8be9d12 CondVar::SignalAll was broken, leading to deadlocks on Windows builds. http://code.google.com/p/leveldb/issues/detail?id=149 c9fc070 Upgrade LevelDB to 1.10.0, mostly for better write stall logging. 8215b15 Tweak to variable name to support unity build git-subtree-dir: src/leveldb git-subtree-split: ae6c2620b2ef3d5c69e63dc0eda865d6a39fa061
82 lines
2.2 KiB
C++
82 lines
2.2 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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#include <algorithm>
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#include <stdint.h>
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#include "leveldb/comparator.h"
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#include "leveldb/slice.h"
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#include "port/port.h"
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#include "util/logging.h"
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namespace leveldb {
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Comparator::~Comparator() { }
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namespace {
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class BytewiseComparatorImpl : public Comparator {
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public:
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BytewiseComparatorImpl() { }
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virtual const char* Name() const {
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return "leveldb.BytewiseComparator";
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}
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virtual int Compare(const Slice& a, const Slice& b) const {
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return a.compare(b);
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}
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virtual void FindShortestSeparator(
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std::string* start,
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const Slice& limit) const {
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// Find length of common prefix
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size_t min_length = std::min(start->size(), limit.size());
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size_t diff_index = 0;
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while ((diff_index < min_length) &&
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((*start)[diff_index] == limit[diff_index])) {
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diff_index++;
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}
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if (diff_index >= min_length) {
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// Do not shorten if one string is a prefix of the other
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} else {
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uint8_t diff_byte = static_cast<uint8_t>((*start)[diff_index]);
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if (diff_byte < static_cast<uint8_t>(0xff) &&
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diff_byte + 1 < static_cast<uint8_t>(limit[diff_index])) {
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(*start)[diff_index]++;
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start->resize(diff_index + 1);
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assert(Compare(*start, limit) < 0);
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}
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}
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}
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virtual void FindShortSuccessor(std::string* key) const {
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// Find first character that can be incremented
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size_t n = key->size();
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for (size_t i = 0; i < n; i++) {
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const uint8_t byte = (*key)[i];
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if (byte != static_cast<uint8_t>(0xff)) {
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(*key)[i] = byte + 1;
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key->resize(i+1);
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return;
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}
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}
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// *key is a run of 0xffs. Leave it alone.
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}
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};
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} // namespace
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static port::OnceType once_comparator = LEVELDB_ONCE_INIT;
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static const Comparator* bytewise;
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static void InitModule() {
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bytewise = new BytewiseComparatorImpl;
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}
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const Comparator* BytewiseComparator() {
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port::InitOnce(&once_comparator, InitModule);
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return bytewise;
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}
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} // namespace leveldb
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