1106 lines
40 KiB
Ruby
1106 lines
40 KiB
Ruby
#! /usr/env/bin ruby
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#--
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# Copyright 2004 Austin Ziegler <diff-lcs@halostatue.ca>
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# adapted from:
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# Algorithm::Diff (Perl) by Ned Konz <perl@bike-nomad.com>
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# Smalltalk by Mario I. Wolczko <mario@wolczko.com>
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# implements McIlroy-Hunt diff algorithm
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#
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# This program is free software. It may be redistributed and/or modified
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# under the terms of the GPL version 2 (or later), the Perl Artistic
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# licence, or the Ruby licence.
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#
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# $Id: lcs.rb,v 1.9 2004/10/17 20:31:10 austin Exp $
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#++
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module Diff
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# = Diff::LCS 1.1.2
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# Computes "intelligent" differences between two sequenced Enumerables.
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# This is an implementation of the McIlroy-Hunt "diff" algorithm for
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# Enumerable objects that include Diffable.
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#
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# Based on Mario I. Wolczko's <mario@wolczko.com> Smalltalk version
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# (1.2, 1993) and Ned Konz's <perl@bike-nomad.com> Perl version
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# (Algorithm::Diff).
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#
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# == Synopsis
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# require 'diff/lcs'
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#
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# seq1 = %w(a b c e h j l m n p)
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# seq2 = %w(b c d e f j k l m r s t)
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#
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# lcs = Diff::LCS.LCS(seq1, seq2)
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# diffs = Diff::LCS.diff(seq1, seq2)
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# sdiff = Diff::LCS.sdiff(seq1, seq2)
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# seq = Diff::LCS.traverse_sequences(seq1, seq2, callback_obj)
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# bal = Diff::LCS.traverse_balanced(seq1, seq2, callback_obj)
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# seq2 == Diff::LCS.patch(seq1, diffs)
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# seq2 == Diff::LCS.patch!(seq1, diffs)
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# seq1 == Diff::LCS.unpatch(seq2, diffs)
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# seq1 == Diff::LCS.unpatch!(seq2, diffs)
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# seq2 == Diff::LCS.patch(seq1, sdiff)
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# seq2 == Diff::LCS.patch!(seq1, sdiff)
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# seq1 == Diff::LCS.unpatch(seq2, sdiff)
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# seq1 == Diff::LCS.unpatch!(seq2, sdiff)
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#
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# Alternatively, objects can be extended with Diff::LCS:
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#
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# seq1.extend(Diff::LCS)
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# lcs = seq1.lcs(seq2)
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# diffs = seq1.diff(seq2)
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# sdiff = seq1.sdiff(seq2)
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# seq = seq1.traverse_sequences(seq2, callback_obj)
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# bal = seq1.traverse_balanced(seq2, callback_obj)
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# seq2 == seq1.patch(diffs)
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# seq2 == seq1.patch!(diffs)
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# seq1 == seq2.unpatch(diffs)
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# seq1 == seq2.unpatch!(diffs)
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# seq2 == seq1.patch(sdiff)
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# seq2 == seq1.patch!(sdiff)
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# seq1 == seq2.unpatch(sdiff)
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# seq1 == seq2.unpatch!(sdiff)
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#
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# Default extensions are provided for Array and String objects through
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# the use of 'diff/lcs/array' and 'diff/lcs/string'.
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#
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# == Introduction (by Mark-Jason Dominus)
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#
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# <em>The following text is from the Perl documentation. The only
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# changes have been to make the text appear better in Rdoc</em>.
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#
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# I once read an article written by the authors of +diff+; they said
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# that they hard worked very hard on the algorithm until they found the
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# right one.
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#
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# I think what they ended up using (and I hope someone will correct me,
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# because I am not very confident about this) was the `longest common
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# subsequence' method. In the LCS problem, you have two sequences of
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# items:
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#
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# a b c d f g h j q z
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# a b c d e f g i j k r x y z
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#
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# and you want to find the longest sequence of items that is present in
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# both original sequences in the same order. That is, you want to find a
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# new sequence *S* which can be obtained from the first sequence by
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# deleting some items, and from the second sequence by deleting other
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# items. You also want *S* to be as long as possible. In this case *S*
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# is:
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#
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# a b c d f g j z
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#
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# From there it's only a small step to get diff-like output:
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#
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# e h i k q r x y
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# + - + + - + + +
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#
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# This module solves the LCS problem. It also includes a canned function
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# to generate +diff+-like output.
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#
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# It might seem from the example above that the LCS of two sequences is
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# always pretty obvious, but that's not always the case, especially when
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# the two sequences have many repeated elements. For example, consider
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#
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# a x b y c z p d q
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# a b c a x b y c z
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#
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# A naive approach might start by matching up the +a+ and +b+ that
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# appear at the beginning of each sequence, like this:
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#
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# a x b y c z p d q
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# a b c a b y c z
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#
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# This finds the common subsequence +a b c z+. But actually, the LCS is
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# +a x b y c z+:
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#
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# a x b y c z p d q
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# a b c a x b y c z
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#
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# == Author
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# This version is by Austin Ziegler <diff-lcs@halostatue.ca>.
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#
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# It is based on the Perl Algorithm::Diff by Ned Konz
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# <perl@bike-nomad.com>, copyright © 2000 - 2002 and the Smalltalk
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# diff version by Mario I. Wolczko <mario@wolczko.com>, copyright ©
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# 1993. Documentation includes work by Mark-Jason Dominus.
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#
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# == Licence
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# Copyright © 2004 Austin Ziegler
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# This program is free software; you can redistribute it and/or modify it
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# under the same terms as Ruby, or alternatively under the Perl Artistic
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# licence.
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#
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# == Credits
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# Much of the documentation is taken directly from the Perl
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# Algorithm::Diff implementation and was written originally by Mark-Jason
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# Dominus <mjd-perl-diff@plover.com> and later by Ned Konz. The basic Ruby
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# implementation was re-ported from the Smalltalk implementation, available
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# at ftp://st.cs.uiuc.edu/pub/Smalltalk/MANCHESTER/manchester/4.0/diff.st
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#
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# #sdiff and #traverse_balanced were written for the Perl version by Mike
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# Schilli <m@perlmeister.com>.
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#
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# "The algorithm is described in <em>A Fast Algorithm for Computing Longest
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# Common Subsequences</em>, CACM, vol.20, no.5, pp.350-353, May 1977, with
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# a few minor improvements to improve the speed."
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module LCS
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VERSION = '1.1.2'
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end
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end
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require 'diff/lcs/callbacks'
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module Diff::LCS
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# Returns an Array containing the longest common subsequence(s) between
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# +self+ and +other+. See Diff::LCS#LCS.
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#
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# lcs = seq1.lcs(seq2)
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def lcs(other, &block) #:yields self[ii] if there are matched subsequences:
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Diff::LCS.LCS(self, other, &block)
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end
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# Returns the difference set between +self+ and +other+. See
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# Diff::LCS#diff.
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def diff(other, callbacks = nil, &block)
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Diff::LCS::diff(self, other, callbacks, &block)
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end
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# Returns the balanced ("side-by-side") difference set between +self+ and
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# +other+. See Diff::LCS#sdiff.
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def sdiff(other, callbacks = nil, &block)
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Diff::LCS::sdiff(self, other, callbacks, &block)
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end
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# Traverses the discovered longest common subsequences between +self+ and
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# +other+. See Diff::LCS#traverse_sequences.
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def traverse_sequences(other, callbacks = nil, &block)
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traverse_sequences(self, other, callbacks || Diff::LCS::YieldingCallbacks,
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&block)
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end
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# Traverses the discovered longest common subsequences between +self+ and
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# +other+ using the alternate, balanced algorithm. See
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# Diff::LCS#traverse_balanced.
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def traverse_balanced(other, callbacks = nil, &block)
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traverse_balanced(self, other, callbacks || Diff::LCS::YieldingCallbacks,
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&block)
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end
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# Attempts to patch a copy of +self+ with the provided +patchset+. See
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# Diff::LCS#patch.
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def patch(patchset)
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Diff::LCS::patch(self.dup, patchset)
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end
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# Attempts to unpatch a copy of +self+ with the provided +patchset+.
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# See Diff::LCS#patch.
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def unpatch(patchset)
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Diff::LCS::unpatch(self.dup, patchset)
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end
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# Attempts to patch +self+ with the provided +patchset+. See
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# Diff::LCS#patch!. Does no autodiscovery.
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def patch!(patchset)
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Diff::LCS::patch!(self, patchset)
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end
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# Attempts to unpatch +self+ with the provided +patchset+. See
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# Diff::LCS#unpatch. Does no autodiscovery.
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def unpatch!(patchset)
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Diff::LCS::unpatch!(self, patchset)
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end
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end
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module Diff::LCS
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class << self
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# Given two sequenced Enumerables, LCS returns an Array containing their
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# longest common subsequences.
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#
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# lcs = Diff::LCS.LCS(seq1, seq2)
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#
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# This array whose contents is such that:
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#
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# lcs.each_with_index do |ee, ii|
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# assert(ee.nil? || (seq1[ii] == seq2[ee]))
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# end
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#
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# If a block is provided, the matching subsequences will be yielded from
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# +seq1+ in turn and may be modified before they are placed into the
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# returned Array of subsequences.
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def LCS(seq1, seq2, &block) #:yields seq1[ii] for each matched:
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matches = Diff::LCS.__lcs(seq1, seq2)
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ret = []
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matches.each_with_index do |ee, ii|
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unless matches[ii].nil?
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if block_given?
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ret << (yield seq1[ii])
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else
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ret << seq1[ii]
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end
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end
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end
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ret
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end
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# Diff::LCS.diff computes the smallest set of additions and deletions
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# necessary to turn the first sequence into the second, and returns a
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# description of these changes.
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#
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# See Diff::LCS::DiffCallbacks for the default behaviour. An alternate
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# behaviour may be implemented with Diff::LCS::ContextDiffCallbacks.
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# If a Class argument is provided for +callbacks+, #diff will attempt
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# to initialise it. If the +callbacks+ object (possibly initialised)
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# responds to #finish, it will be called.
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def diff(seq1, seq2, callbacks = nil, &block) # :yields diff changes:
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callbacks ||= Diff::LCS::DiffCallbacks
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if callbacks.kind_of?(Class)
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cb = callbacks.new rescue callbacks
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callbacks = cb
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end
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traverse_sequences(seq1, seq2, callbacks)
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callbacks.finish if callbacks.respond_to?(:finish)
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if block_given?
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res = callbacks.diffs.map do |hunk|
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if hunk.kind_of?(Array)
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hunk = hunk.map { |block| yield block }
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else
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yield hunk
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end
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end
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res
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else
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callbacks.diffs
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end
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end
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# Diff::LCS.sdiff computes all necessary components to show two sequences
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# and their minimized differences side by side, just like the Unix
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# utility <em>sdiff</em> does:
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#
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# old < -
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# same same
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# before | after
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# - > new
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#
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# See Diff::LCS::SDiffCallbacks for the default behaviour. An alternate
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# behaviour may be implemented with Diff::LCS::ContextDiffCallbacks. If
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# a Class argument is provided for +callbacks+, #diff will attempt to
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# initialise it. If the +callbacks+ object (possibly initialised)
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# responds to #finish, it will be called.
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def sdiff(seq1, seq2, callbacks = nil, &block) #:yields diff changes:
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callbacks ||= Diff::LCS::SDiffCallbacks
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if callbacks.kind_of?(Class)
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cb = callbacks.new rescue callbacks
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callbacks = cb
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end
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traverse_balanced(seq1, seq2, callbacks)
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callbacks.finish if callbacks.respond_to?(:finish)
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if block_given?
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res = callbacks.diffs.map do |hunk|
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if hunk.kind_of?(Array)
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hunk = hunk.map { |block| yield block }
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else
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yield hunk
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end
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end
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res
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else
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callbacks.diffs
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end
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end
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# Diff::LCS.traverse_sequences is the most general facility provided by this
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# module; +diff+ and +LCS+ are implemented as calls to it.
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#
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# The arguments to #traverse_sequences are the two sequences to
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# traverse, and a callback object, like this:
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#
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# traverse_sequences(seq1, seq2, Diff::LCS::ContextDiffCallbacks.new)
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#
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# #diff is implemented with #traverse_sequences.
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#
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# == Callback Methods
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# Optional callback methods are <em>emphasized</em>.
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#
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# callbacks#match:: Called when +a+ and +b+ are pointing
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# to common elements in +A+ and +B+.
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# callbacks#discard_a:: Called when +a+ is pointing to an
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# element not in +B+.
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# callbacks#discard_b:: Called when +b+ is pointing to an
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# element not in +A+.
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# <em>callbacks#finished_a</em>:: Called when +a+ has reached the end of
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# sequence +A+.
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# <em>callbacks#finished_b</em>:: Called when +b+ has reached the end of
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# sequence +B+.
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#
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# == Algorithm
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# a---+
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# v
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# A = a b c e h j l m n p
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# B = b c d e f j k l m r s t
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# ^
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# b---+
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#
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# If there are two arrows (+a+ and +b+) pointing to elements of
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# sequences +A+ and +B+, the arrows will initially point to the first
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# elements of their respective sequences. #traverse_sequences will
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# advance the arrows through the sequences one element at a time,
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# calling a method on the user-specified callback object before each
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# advance. It will advance the arrows in such a way that if there are
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# elements <tt>A[ii]</tt> and <tt>B[jj]</tt> which are both equal and
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# part of the longest common subsequence, there will be some moment
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# during the execution of #traverse_sequences when arrow +a+ is pointing
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# to <tt>A[ii]</tt> and arrow +b+ is pointing to <tt>B[jj]</tt>. When
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# this happens, #traverse_sequences will call <tt>callbacks#match</tt>
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# and then it will advance both arrows.
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#
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# Otherwise, one of the arrows is pointing to an element of its sequence
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# that is not part of the longest common subsequence.
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# #traverse_sequences will advance that arrow and will call
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# <tt>callbacks#discard_a</tt> or <tt>callbacks#discard_b</tt>, depending
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# on which arrow it advanced. If both arrows point to elements that are
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# not part of the longest common subsequence, then #traverse_sequences
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# will advance one of them and call the appropriate callback, but it is
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# not specified which it will call.
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#
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# The methods for <tt>callbacks#match</tt>, <tt>callbacks#discard_a</tt>,
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# and <tt>callbacks#discard_b</tt> are invoked with an event comprising
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# the action ("=", "+", or "-", respectively), the indicies +ii+ and
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# +jj+, and the elements <tt>A[ii]</tt> and <tt>B[jj]</tt>. Return
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# values are discarded by #traverse_sequences.
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#
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# === End of Sequences
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# If arrow +a+ reaches the end of its sequence before arrow +b+ does,
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# #traverse_sequence try to call <tt>callbacks#finished_a</tt> with the
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# last index and element of +A+ (<tt>A[-1]</tt>) and the current index
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# and element of +B+ (<tt>B[jj]</tt>). If <tt>callbacks#finished_a</tt>
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# does not exist, then <tt>callbacks#discard_b</tt> will be called on
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# each element of +B+ until the end of the sequence is reached (the call
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# will be done with <tt>A[-1]</tt> and <tt>B[jj]</tt> for each element).
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#
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# If +b+ reaches the end of +B+ before +a+ reaches the end of +A+,
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# <tt>callbacks#finished_b</tt> will be called with the current index
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# and element of +A+ (<tt>A[ii]</tt>) and the last index and element of
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# +B+ (<tt>A[-1]</tt>). Again, if <tt>callbacks#finished_b</tt> does not
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# exist on the callback object, then <tt>callbacks#discard_a</tt> will
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# be called on each element of +A+ until the end of the sequence is
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# reached (<tt>A[ii]</tt> and <tt>B[-1]</tt>).
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#
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# There is a chance that one additional <tt>callbacks#discard_a</tt> or
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# <tt>callbacks#discard_b</tt> will be called after the end of the
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# sequence is reached, if +a+ has not yet reached the end of +A+ or +b+
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# has not yet reached the end of +B+.
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def traverse_sequences(seq1, seq2, callbacks = Diff::LCS::SequenceCallbacks, &block) #:yields change events:
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matches = Diff::LCS.__lcs(seq1, seq2)
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run_finished_a = run_finished_b = false
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string = seq1.kind_of?(String)
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a_size = seq1.size
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b_size = seq2.size
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ai = bj = 0
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(0 .. matches.size).each do |ii|
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b_line = matches[ii]
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ax = string ? seq1[ii, 1] : seq1[ii]
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bx = string ? seq2[bj, 1] : seq2[bj]
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if b_line.nil?
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unless ax.nil?
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event = Diff::LCS::ContextChange.new('-', ii, ax, bj, bx)
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event = yield event if block_given?
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callbacks.discard_a(event)
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end
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else
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loop do
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break unless bj < b_line
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bx = string ? seq2[bj, 1] : seq2[bj]
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event = Diff::LCS::ContextChange.new('+', ii, ax, bj, bx)
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event = yield event if block_given?
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callbacks.discard_b(event)
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bj += 1
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end
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bx = string ? seq2[bj, 1] : seq2[bj]
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event = Diff::LCS::ContextChange.new('=', ii, ax, bj, bx)
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event = yield event if block_given?
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callbacks.match(event)
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bj += 1
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end
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ai = ii
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end
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ai += 1
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# The last entry (if any) processed was a match. +ai+ and +bj+ point
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# just past the last matching lines in their sequences.
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while (ai < a_size) or (bj < b_size)
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# last A?
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if ai == a_size and bj < b_size
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if callbacks.respond_to?(:finished_a) and not run_finished_a
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ax = string ? seq1[-1, 1] : seq1[-1]
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bx = string ? seq2[bj, 1] : seq2[bj]
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event = Diff::LCS::ContextChange.new('>', (a_size - 1), ax, bj, bx)
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event = yield event if block_given?
|
|
callbacks.finished_a(event)
|
|
run_finished_a = true
|
|
else
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
loop do
|
|
bx = string ? seq2[bj, 1] : seq2[bj]
|
|
event = Diff::LCS::ContextChange.new('+', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_b(event)
|
|
bj += 1
|
|
break unless bj < b_size
|
|
end
|
|
end
|
|
end
|
|
|
|
# last B?
|
|
if bj == b_size and ai < a_size
|
|
if callbacks.respond_to?(:finished_b) and not run_finished_b
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
bx = string ? seq2[-1, 1] : seq2[-1]
|
|
event = Diff::LCS::ContextChange.new('<', ai, ax, (b_size - 1), bx)
|
|
event = yield event if block_given?
|
|
callbacks.finished_b(event)
|
|
run_finished_b = true
|
|
else
|
|
bx = string ? seq2[bj, 1] : seq2[bj]
|
|
loop do
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
event = Diff::LCS::ContextChange.new('-', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_a(event)
|
|
ai += 1
|
|
break unless bj < b_size
|
|
end
|
|
end
|
|
end
|
|
|
|
if ai < a_size
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
bx = string ? seq2[bj, 1] : seq2[bj]
|
|
event = Diff::LCS::ContextChange.new('-', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_a(event)
|
|
ai += 1
|
|
end
|
|
|
|
if bj < b_size
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
bx = string ? seq2[bj, 1] : seq2[bj]
|
|
event = Diff::LCS::ContextChange.new('+', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_b(event)
|
|
bj += 1
|
|
end
|
|
end
|
|
end
|
|
|
|
# #traverse_balanced is an alternative to #traverse_sequences. It
|
|
# uses a different algorithm to iterate through the entries in the
|
|
# computed longest common subsequence. Instead of viewing the changes as
|
|
# insertions or deletions from one of the sequences, #traverse_balanced
|
|
# will report <em>changes</em> between the sequences. To represent a
|
|
#
|
|
# The arguments to #traverse_balanced are the two sequences to traverse
|
|
# and a callback object, like this:
|
|
#
|
|
# traverse_balanced(seq1, seq2, Diff::LCS::ContextDiffCallbacks.new)
|
|
#
|
|
# #sdiff is implemented with #traverse_balanced.
|
|
#
|
|
# == Callback Methods
|
|
# Optional callback methods are <em>emphasized</em>.
|
|
#
|
|
# callbacks#match:: Called when +a+ and +b+ are pointing
|
|
# to common elements in +A+ and +B+.
|
|
# callbacks#discard_a:: Called when +a+ is pointing to an
|
|
# element not in +B+.
|
|
# callbacks#discard_b:: Called when +b+ is pointing to an
|
|
# element not in +A+.
|
|
# <em>callbacks#change</em>:: Called when +a+ and +b+ are pointing
|
|
# to the same relative position, but
|
|
# <tt>A[a]</tt> and <tt>B[b]</tt> are
|
|
# not the same; a <em>change</em> has
|
|
# occurred.
|
|
#
|
|
# #traverse_balanced might be a bit slower than #traverse_sequences,
|
|
# noticable only while processing huge amounts of data.
|
|
#
|
|
# The +sdiff+ function of this module is implemented as call to
|
|
# #traverse_balanced.
|
|
#
|
|
# == Algorithm
|
|
# a---+
|
|
# v
|
|
# A = a b c e h j l m n p
|
|
# B = b c d e f j k l m r s t
|
|
# ^
|
|
# b---+
|
|
#
|
|
# === Matches
|
|
# If there are two arrows (+a+ and +b+) pointing to elements of
|
|
# sequences +A+ and +B+, the arrows will initially point to the first
|
|
# elements of their respective sequences. #traverse_sequences will
|
|
# advance the arrows through the sequences one element at a time,
|
|
# calling a method on the user-specified callback object before each
|
|
# advance. It will advance the arrows in such a way that if there are
|
|
# elements <tt>A[ii]</tt> and <tt>B[jj]</tt> which are both equal and
|
|
# part of the longest common subsequence, there will be some moment
|
|
# during the execution of #traverse_sequences when arrow +a+ is pointing
|
|
# to <tt>A[ii]</tt> and arrow +b+ is pointing to <tt>B[jj]</tt>. When
|
|
# this happens, #traverse_sequences will call <tt>callbacks#match</tt>
|
|
# and then it will advance both arrows.
|
|
#
|
|
# === Discards
|
|
# Otherwise, one of the arrows is pointing to an element of its sequence
|
|
# that is not part of the longest common subsequence.
|
|
# #traverse_sequences will advance that arrow and will call
|
|
# <tt>callbacks#discard_a</tt> or <tt>callbacks#discard_b</tt>,
|
|
# depending on which arrow it advanced.
|
|
#
|
|
# === Changes
|
|
# If both +a+ and +b+ point to elements that are not part of the longest
|
|
# common subsequence, then #traverse_sequences will try to call
|
|
# <tt>callbacks#change</tt> and advance both arrows. If
|
|
# <tt>callbacks#change</tt> is not implemented, then
|
|
# <tt>callbacks#discard_a</tt> and <tt>callbacks#discard_b</tt> will be
|
|
# called in turn.
|
|
#
|
|
# The methods for <tt>callbacks#match</tt>, <tt>callbacks#discard_a</tt>,
|
|
# <tt>callbacks#discard_b</tt>, and <tt>callbacks#change</tt> are
|
|
# invoked with an event comprising the action ("=", "+", "-", or "!",
|
|
# respectively), the indicies +ii+ and +jj+, and the elements
|
|
# <tt>A[ii]</tt> and <tt>B[jj]</tt>. Return values are discarded by
|
|
# #traverse_balanced.
|
|
#
|
|
# === Context
|
|
# Note that +ii+ and +jj+ may not be the same index position, even if
|
|
# +a+ and +b+ are considered to be pointing to matching or changed
|
|
# elements.
|
|
def traverse_balanced(seq1, seq2, callbacks = Diff::LCS::BalancedCallbacks)
|
|
matches = Diff::LCS.__lcs(seq1, seq2)
|
|
a_size = seq1.size
|
|
b_size = seq2.size
|
|
ai = bj = mb = 0
|
|
ma = -1
|
|
string = seq1.kind_of?(String)
|
|
|
|
# Process all the lines in the match vector.
|
|
loop do
|
|
# Find next match indices +ma+ and +mb+
|
|
loop do
|
|
ma += 1
|
|
break unless ma < matches.size and matches[ma].nil?
|
|
end
|
|
|
|
break if ma >= matches.size # end of matches?
|
|
mb = matches[ma]
|
|
|
|
# Change(seq2)
|
|
while (ai < ma) or (bj < mb)
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
bx = string ? seq2[bj, 1] : seq2[bj]
|
|
|
|
case [(ai < ma), (bj < mb)]
|
|
when [true, true]
|
|
if callbacks.respond_to?(:change)
|
|
event = Diff::LCS::ContextChange.new('!', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.change(event)
|
|
ai += 1
|
|
bj += 1
|
|
else
|
|
event = Diff::LCS::ContextChange.new('-', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_a(event)
|
|
ai += 1
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
event = Diff::LCS::ContextChange.new('+', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_b(event)
|
|
bj += 1
|
|
end
|
|
when [true, false]
|
|
event = Diff::LCS::ContextChange.new('-', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_a(event)
|
|
ai += 1
|
|
when [false, true]
|
|
event = Diff::LCS::ContextChange.new('+', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_b(event)
|
|
bj += 1
|
|
end
|
|
end
|
|
|
|
# Match
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
bx = string ? seq2[bj, 1] : seq2[bj]
|
|
event = Diff::LCS::ContextChange.new('=', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.match(event)
|
|
ai += 1
|
|
bj += 1
|
|
end
|
|
|
|
while (ai < a_size) or (bj < b_size)
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
bx = string ? seq2[bj, 1] : seq2[bj]
|
|
|
|
case [(ai < a_size), (bj < b_size)]
|
|
when [true, true]
|
|
if callbacks.respond_to?(:change)
|
|
event = Diff::LCS::ContextChange.new('!', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.change(event)
|
|
ai += 1
|
|
bj += 1
|
|
else
|
|
event = Diff::LCS::ContextChange.new('-', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_a(event)
|
|
ai += 1
|
|
ax = string ? seq1[ai, 1] : seq1[ai]
|
|
event = Diff::LCS::ContextChange.new('+', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_b(event)
|
|
bj += 1
|
|
end
|
|
when [true, false]
|
|
event = Diff::LCS::ContextChange.new('-', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_a(event)
|
|
ai += 1
|
|
when [false, true]
|
|
event = Diff::LCS::ContextChange.new('+', ai, ax, bj, bx)
|
|
event = yield event if block_given?
|
|
callbacks.discard_b(event)
|
|
bj += 1
|
|
end
|
|
end
|
|
end
|
|
|
|
PATCH_MAP = { #:nodoc:
|
|
:patch => { '+' => '+', '-' => '-', '!' => '!', '=' => '=' },
|
|
:unpatch => { '+' => '-', '-' => '+', '!' => '!', '=' => '=' }
|
|
}
|
|
|
|
# Given a patchset, convert the current version to the new
|
|
# version. If +direction+ is not specified (must be
|
|
# <tt>:patch</tt> or <tt>:unpatch</tt>), then discovery of the
|
|
# direction of the patch will be attempted.
|
|
def patch(src, patchset, direction = nil)
|
|
string = src.kind_of?(String)
|
|
# Start with a new empty type of the source's class
|
|
res = src.class.new
|
|
|
|
# Normalize the patchset.
|
|
patchset = __normalize_patchset(patchset)
|
|
|
|
direction ||= Diff::LCS.__diff_direction(src, patchset)
|
|
direction ||= :patch
|
|
|
|
ai = bj = 0
|
|
|
|
patchset.each do |change|
|
|
# Both Change and ContextChange support #action
|
|
action = PATCH_MAP[direction][change.action]
|
|
|
|
case change
|
|
when Diff::LCS::ContextChange
|
|
case direction
|
|
when :patch
|
|
el = change.new_element
|
|
op = change.old_position
|
|
np = change.new_position
|
|
when :unpatch
|
|
el = change.old_element
|
|
op = change.new_position
|
|
np = change.old_position
|
|
end
|
|
|
|
case action
|
|
when '-' # Remove details from the old string
|
|
while ai < op
|
|
res << (string ? src[ai, 1] : src[ai])
|
|
ai += 1
|
|
bj += 1
|
|
end
|
|
ai += 1
|
|
when '+'
|
|
while bj < np
|
|
res << (string ? src[ai, 1] : src[ai])
|
|
ai += 1
|
|
bj += 1
|
|
end
|
|
|
|
res << el
|
|
bj += 1
|
|
when '='
|
|
# This only appears in sdiff output with the SDiff callback.
|
|
# Therefore, we only need to worry about dealing with a single
|
|
# element.
|
|
res << el
|
|
|
|
ai += 1
|
|
bj += 1
|
|
when '!'
|
|
while ai < op
|
|
res << (string ? src[ai, 1] : src[ai])
|
|
ai += 1
|
|
bj += 1
|
|
end
|
|
|
|
bj += 1
|
|
ai += 1
|
|
|
|
res << el
|
|
end
|
|
when Diff::LCS::Change
|
|
case action
|
|
when '-'
|
|
while ai < change.position
|
|
res << (string ? src[ai, 1] : src[ai])
|
|
ai += 1
|
|
bj += 1
|
|
end
|
|
ai += 1
|
|
when '+'
|
|
while bj < change.position
|
|
res << (string ? src[ai, 1] : src[ai])
|
|
ai += 1
|
|
bj += 1
|
|
end
|
|
|
|
bj += 1
|
|
|
|
res << change.element
|
|
end
|
|
end
|
|
end
|
|
|
|
while ai < src.size
|
|
res << (string ? src[ai, 1] : src[ai])
|
|
ai += 1
|
|
bj += 1
|
|
end
|
|
|
|
res
|
|
end
|
|
|
|
# Given a set of patchset, convert the current version to the prior
|
|
# version. Does no auto-discovery.
|
|
def unpatch!(src, patchset)
|
|
Diff::LCS.patch(src, patchset, :unpatch)
|
|
end
|
|
|
|
# Given a set of patchset, convert the current version to the next
|
|
# version. Does no auto-discovery.
|
|
def patch!(src, patchset)
|
|
Diff::LCS.patch(src, patchset, :patch)
|
|
end
|
|
|
|
# private
|
|
# Compute the longest common subsequence between the sequenced Enumerables
|
|
# +a+ and +b+. The result is an array whose contents is such that
|
|
#
|
|
# result = Diff::LCS.__lcs(a, b)
|
|
# result.each_with_index do |e, ii|
|
|
# assert_equal(a[ii], b[e]) unless e.nil?
|
|
# end
|
|
def __lcs(a, b)
|
|
a_start = b_start = 0
|
|
a_finish = a.size - 1
|
|
b_finish = b.size - 1
|
|
vector = []
|
|
|
|
# Prune off any common elements at the beginning...
|
|
while (a_start <= a_finish) and
|
|
(b_start <= b_finish) and
|
|
(a[a_start] == b[b_start])
|
|
vector[a_start] = b_start
|
|
a_start += 1
|
|
b_start += 1
|
|
end
|
|
|
|
# Now the end...
|
|
while (a_start <= a_finish) and
|
|
(b_start <= b_finish) and
|
|
(a[a_finish] == b[b_finish])
|
|
vector[a_finish] = b_finish
|
|
a_finish -= 1
|
|
b_finish -= 1
|
|
end
|
|
|
|
# Now, compute the equivalence classes of positions of elements.
|
|
b_matches = Diff::LCS.__position_hash(b, b_start .. b_finish)
|
|
|
|
thresh = []
|
|
links = []
|
|
|
|
(a_start .. a_finish).each do |ii|
|
|
ai = a.kind_of?(String) ? a[ii, 1] : a[ii]
|
|
bm = b_matches[ai]
|
|
kk = nil
|
|
bm.reverse_each do |jj|
|
|
if kk and (thresh[kk] > jj) and (thresh[kk - 1] < jj)
|
|
thresh[kk] = jj
|
|
else
|
|
kk = Diff::LCS.__replace_next_larger(thresh, jj, kk)
|
|
end
|
|
links[kk] = [ (kk > 0) ? links[kk - 1] : nil, ii, jj ] unless kk.nil?
|
|
end
|
|
end
|
|
|
|
unless thresh.empty?
|
|
link = links[thresh.size - 1]
|
|
while not link.nil?
|
|
vector[link[1]] = link[2]
|
|
link = link[0]
|
|
end
|
|
end
|
|
|
|
vector
|
|
end
|
|
|
|
# Find the place at which +value+ would normally be inserted into the
|
|
# Enumerable. If that place is already occupied by +value+, do nothing
|
|
# and return +nil+. If the place does not exist (i.e., it is off the end
|
|
# of the Enumerable), add it to the end. Otherwise, replace the element
|
|
# at that point with +value+. It is assumed that the Enumerable's values
|
|
# are numeric.
|
|
#
|
|
# This operation preserves the sort order.
|
|
def __replace_next_larger(enum, value, last_index = nil)
|
|
# Off the end?
|
|
if enum.empty? or (value > enum[-1])
|
|
enum << value
|
|
return enum.size - 1
|
|
end
|
|
|
|
# Binary search for the insertion point
|
|
last_index ||= enum.size
|
|
first_index = 0
|
|
while (first_index <= last_index)
|
|
ii = (first_index + last_index) >> 1
|
|
|
|
found = enum[ii]
|
|
|
|
if value == found
|
|
return nil
|
|
elsif value > found
|
|
first_index = ii + 1
|
|
else
|
|
last_index = ii - 1
|
|
end
|
|
end
|
|
|
|
# The insertion point is in first_index; overwrite the next larger
|
|
# value.
|
|
enum[first_index] = value
|
|
return first_index
|
|
end
|
|
|
|
# If +vector+ maps the matching elements of another collection onto this
|
|
# Enumerable, compute the inverse +vector+ that maps this Enumerable
|
|
# onto the collection. (Currently unused.)
|
|
def __inverse_vector(a, vector)
|
|
inverse = a.dup
|
|
(0 ... vector.size).each do |ii|
|
|
inverse[vector[ii]] = ii unless vector[ii].nil?
|
|
end
|
|
inverse
|
|
end
|
|
|
|
# Returns a hash mapping each element of an Enumerable to the set of
|
|
# positions it occupies in the Enumerable, optionally restricted to the
|
|
# elements specified in the range of indexes specified by +interval+.
|
|
def __position_hash(enum, interval = 0 .. -1)
|
|
hash = Hash.new { |hh, kk| hh[kk] = [] }
|
|
interval.each do |ii|
|
|
kk = enum.kind_of?(String) ? enum[ii, 1] : enum[ii]
|
|
hash[kk] << ii
|
|
end
|
|
hash
|
|
end
|
|
|
|
# Examine the patchset and the source to see in which direction the
|
|
# patch should be applied.
|
|
#
|
|
# WARNING: By default, this examines the whole patch, so this could take
|
|
# some time. This also works better with Diff::LCS::ContextChange or
|
|
# Diff::LCS::Change as its source, as an array will cause the creation
|
|
# of one of the above.
|
|
def __diff_direction(src, patchset, limit = nil)
|
|
count = left = left_miss = right = right_miss = 0
|
|
string = src.kind_of?(String)
|
|
|
|
patchset.each do |change|
|
|
count += 1
|
|
|
|
case change
|
|
when Diff::LCS::Change
|
|
# With a simplistic change, we can't tell the difference between
|
|
# the left and right on '!' actions, so we ignore those. On '='
|
|
# actions, if there's a miss, we miss both left and right.
|
|
element = string ? src[change.position, 1] : src[change.position]
|
|
|
|
case change.action
|
|
when '-'
|
|
if element == change.element
|
|
left += 1
|
|
else
|
|
left_miss += 1
|
|
end
|
|
when '+'
|
|
if element == change.element
|
|
right += 1
|
|
else
|
|
right_miss += 1
|
|
end
|
|
when '='
|
|
if element != change.element
|
|
left_miss += 1
|
|
right_miss += 1
|
|
end
|
|
end
|
|
when Diff::LCS::ContextChange
|
|
case change.action
|
|
when '-' # Remove details from the old string
|
|
element = string ? src[change.old_position, 1] : src[change.old_position]
|
|
if element == change.old_element
|
|
left += 1
|
|
else
|
|
left_miss += 1
|
|
end
|
|
when '+'
|
|
element = string ? src[change.new_position, 1] : src[change.new_position]
|
|
if element == change.new_element
|
|
right += 1
|
|
else
|
|
right_miss += 1
|
|
end
|
|
when '='
|
|
le = string ? src[change.old_position, 1] : src[change.old_position]
|
|
re = string ? src[change.new_position, 1] : src[change.new_position]
|
|
|
|
left_miss += 1 if le != change.old_element
|
|
right_miss += 1 if re != change.new_element
|
|
when '!'
|
|
element = string ? src[change.old_position, 1] : src[change.old_position]
|
|
if element == change.old_element
|
|
left += 1
|
|
else
|
|
element = string ? src[change.new_position, 1] : src[change.new_position]
|
|
if element == change.new_element
|
|
right += 1
|
|
else
|
|
left_miss += 1
|
|
right_miss += 1
|
|
end
|
|
end
|
|
end
|
|
end
|
|
|
|
break if not limit.nil? and count > limit
|
|
end
|
|
|
|
no_left = (left == 0) and (left_miss >= 0)
|
|
no_right = (right == 0) and (right_miss >= 0)
|
|
|
|
case [no_left, no_right]
|
|
when [false, true]
|
|
return :patch
|
|
when [true, false]
|
|
return :unpatch
|
|
else
|
|
raise "The provided patchset does not appear to apply to the provided value as either source or destination value."
|
|
end
|
|
end
|
|
|
|
# Normalize the patchset. A patchset is always a sequence of changes, but
|
|
# how those changes are represented may vary, depending on how they were
|
|
# generated. In all cases we support, we also support the array
|
|
# representation of the changes. The formats are:
|
|
#
|
|
# [ # patchset <- Diff::LCS.diff(a, b)
|
|
# [ # one or more hunks
|
|
# Diff::LCS::Change # one or more changes
|
|
# ] ]
|
|
#
|
|
# [ # patchset, equivalent to the above
|
|
# [ # one or more hunks
|
|
# [ action, line, value ] # one or more changes
|
|
# ] ]
|
|
#
|
|
# [ # patchset <- Diff::LCS.diff(a, b, Diff::LCS::ContextDiffCallbacks)
|
|
# # OR <- Diff::LCS.sdiff(a, b, Diff::LCS::ContextDiffCallbacks)
|
|
# [ # one or more hunks
|
|
# Diff::LCS::ContextChange # one or more changes
|
|
# ] ]
|
|
#
|
|
# [ # patchset, equivalent to the above
|
|
# [ # one or more hunks
|
|
# [ action, [ old line, old value ], [ new line, new value ] ]
|
|
# # one or more changes
|
|
# ] ]
|
|
#
|
|
# [ # patchset <- Diff::LCS.sdiff(a, b)
|
|
# # OR <- Diff::LCS.diff(a, b, Diff::LCS::SDiffCallbacks)
|
|
# Diff::LCS::ContextChange # one or more changes
|
|
# ]
|
|
#
|
|
# [ # patchset, equivalent to the above
|
|
# [ action, [ old line, old value ], [ new line, new value ] ]
|
|
# # one or more changes
|
|
# ]
|
|
#
|
|
# The result of this will be either of the following.
|
|
#
|
|
# [ # patchset
|
|
# Diff::LCS::ContextChange # one or more changes
|
|
# ]
|
|
#
|
|
# [ # patchset
|
|
# Diff::LCS::Change # one or more changes
|
|
# ]
|
|
#
|
|
# If either of the above is provided, it will be returned as such.
|
|
#
|
|
def __normalize_patchset(patchset)
|
|
patchset.map do |hunk|
|
|
case hunk
|
|
when Diff::LCS::ContextChange, Diff::LCS::Change
|
|
hunk
|
|
when Array
|
|
if (not hunk[0].kind_of?(Array)) and hunk[1].kind_of?(Array) and hunk[2].kind_of?(Array)
|
|
Diff::LCS::ContextChange.from_a(hunk)
|
|
else
|
|
hunk.map do |change|
|
|
case change
|
|
when Diff::LCS::ContextChange, Diff::LCS::Change
|
|
change
|
|
when Array
|
|
# change[1] will ONLY be an array in a ContextChange#to_a call.
|
|
# In Change#to_a, it represents the line (singular).
|
|
if change[1].kind_of?(Array)
|
|
Diff::LCS::ContextChange.from_a(change)
|
|
else
|
|
Diff::LCS::Change.from_a(change)
|
|
end
|
|
end
|
|
end
|
|
end
|
|
else
|
|
raise ArgumentError, "Cannot normalise a hunk of class #{hunk.class}."
|
|
end
|
|
end.flatten
|
|
end
|
|
end
|
|
end
|