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
52 lines
1.3 KiB
C++
52 lines
1.3 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 <string.h>
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#include "util/coding.h"
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#include "util/hash.h"
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// The FALLTHROUGH_INTENDED macro can be used to annotate implicit fall-through
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// between switch labels. The real definition should be provided externally.
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// This one is a fallback version for unsupported compilers.
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#ifndef FALLTHROUGH_INTENDED
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#define FALLTHROUGH_INTENDED do { } while (0)
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#endif
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namespace leveldb {
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uint32_t Hash(const char* data, size_t n, uint32_t seed) {
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// Similar to murmur hash
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const uint32_t m = 0xc6a4a793;
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const uint32_t r = 24;
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const char* limit = data + n;
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uint32_t h = seed ^ (n * m);
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// Pick up four bytes at a time
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while (data + 4 <= limit) {
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uint32_t w = DecodeFixed32(data);
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data += 4;
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h += w;
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h *= m;
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h ^= (h >> 16);
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}
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// Pick up remaining bytes
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switch (limit - data) {
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case 3:
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h += data[2] << 16;
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FALLTHROUGH_INTENDED;
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case 2:
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h += data[1] << 8;
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FALLTHROUGH_INTENDED;
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case 1:
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h += data[0];
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h *= m;
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h ^= (h >> r);
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break;
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}
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return h;
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}
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} // namespace leveldb
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