42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
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// 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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//
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// Class for specifying user-defined functions which perform a
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// transformation on a slice. It is not required that every slice
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// belong to the domain and/or range of a function. Subclasses should
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// define InDomain and InRange to determine which slices are in either
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// of these sets respectively.
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#ifndef STORAGE_LEVELDB_INCLUDE_SLICE_TRANSFORM_H_
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#define STORAGE_LEVELDB_INCLUDE_SLICE_TRANSFORM_H_
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#include <string>
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namespace leveldb {
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class Slice;
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class SliceTransform {
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public:
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virtual ~SliceTransform() {};
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// Return the name of this transformation.
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virtual const char* Name() const = 0;
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// transform a src in domain to a dst in the range
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virtual Slice Transform(const Slice& src) const = 0;
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// determine whether this is a valid src upon the function applies
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virtual bool InDomain(const Slice& src) const = 0;
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// determine whether dst=Transform(src) for some src
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virtual bool InRange(const Slice& dst) const = 0;
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};
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extern const SliceTransform* NewFixedPrefixTransform(size_t prefix_len);
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}
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#endif // STORAGE_LEVELDB_INCLUDE_SLICE_TRANSFORM_H_
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