f5f1842282
Summary: Similar to v2 (db and table code understands prefixes), but use ReadOptions as in v3. Also, make the CreateFilter code faster and cleaner. Test Plan: make db_test; export LEVELDB_TESTS=PrefixScan; ./db_test Reviewers: dhruba Reviewed By: dhruba CC: haobo, emayanke Differential Revision: https://reviews.facebook.net/D12027
44 lines
1.0 KiB
C++
44 lines
1.0 KiB
C++
// Copyright (c) 2012 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 "leveldb/slice_transform.h"
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#include "leveldb/slice.h"
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namespace leveldb {
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namespace {
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class FixedPrefixTransform : public SliceTransform {
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private:
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size_t prefix_len_;
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public:
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explicit FixedPrefixTransform(size_t prefix_len) : prefix_len_(prefix_len) { }
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virtual const char* Name() const {
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return "rocksdb.FixedPrefix";
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}
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virtual Slice Transform(const Slice& src) const {
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assert(InDomain(src));
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return Slice(src.data(), prefix_len_);
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}
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virtual bool InDomain(const Slice& src) const {
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return (src.size() >= prefix_len_);
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}
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virtual bool InRange(const Slice& dst) const {
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return (dst.size() == prefix_len_);
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}
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};
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}
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const SliceTransform* NewFixedPrefixTransform(size_t prefix_len) {
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return new FixedPrefixTransform(prefix_len);
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}
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} // namespace leveldb
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