| Index: third_party/courgette/difference_estimator.h
|
| ===================================================================
|
| --- third_party/courgette/difference_estimator.h (revision 15668)
|
| +++ third_party/courgette/difference_estimator.h (working copy)
|
| @@ -1,58 +0,0 @@
|
| -// Copyright (c) 2009 The Chromium Authors. All rights reserved.
|
| -// Use of this source code is governed by a BSD-style license that can be
|
| -// found in the LICENSE file.
|
| -
|
| -// A DifferenceEstimator class provides a means for quickly estimating the
|
| -// difference between two regions of memory.
|
| -
|
| -#ifndef COURGETTE_DIFFERENCE_ESTIMATOR_H_
|
| -#define COURGETTE_DIFFERENCE_ESTIMATOR_H_
|
| -
|
| -#include <vector>
|
| -
|
| -#include "third_party/courgette/region.h"
|
| -
|
| -namespace courgette {
|
| -
|
| -// A DifferenceEstimator simplifies the task of determining which 'Subject' byte
|
| -// strings (stored in regions of memory) are good matches to existing 'Base'
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| -// regions. The ultimate measure would be to try full differential compression
|
| -// and measure the output size, but an estimate that correlates well with the
|
| -// full compression is more efficient.
|
| -//
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| -// The measure is asymmetric, if the Subject is a small substring of the Base
|
| -// then it should match very well.
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| -//
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| -// The comparison is staged: first make Base and Subject objects for the regions
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| -// and then call 'Measure' to get the estimate. The staging allows multiple
|
| -// comparisons to be more efficient by precomputing information used in the
|
| -// comparison.
|
| -//
|
| -class DifferenceEstimator {
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| - public:
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| - DifferenceEstimator();
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| - ~DifferenceEstimator();
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| -
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| - class Base;
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| - class Subject;
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| -
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| - // This DifferenceEstimator owns the objects returned by MakeBase and
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| - // MakeSubject. Caller continues to own memory at |region| and must not free
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| - // it until ~DifferenceEstimator has been called.
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| - Base* MakeBase(const Region& region);
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| - Subject* MakeSubject(const Region& region);
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| -
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| - // Returns a value correlated with the size of the bsdiff or xdelta difference
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| - // from |base| to |subject|. Returns zero iff the base and subject regions
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| - // are bytewise identical.
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| - size_t Measure(Base* base, Subject* subject);
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| -
|
| - private:
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| - std::vector<Base*> owned_bases_;
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| - std::vector<Subject*> owned_subjects_;
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| - DISALLOW_COPY_AND_ASSIGN(DifferenceEstimator);
|
| -};
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| -
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| -} // namespace
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| -
|
| -#endif // COURGETTE_DIFFERENCE_ESTIMATOR_H_
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|
|