1 | # This is a version of Algorithm::Diff that uses only a comparison function,
|
---|
2 | # like versions <= 0.59 used to.
|
---|
3 | # $Revision: 1.3 $
|
---|
4 |
|
---|
5 | package Algorithm::DiffOld;
|
---|
6 | use strict;
|
---|
7 | use vars qw($VERSION @EXPORT_OK @ISA @EXPORT);
|
---|
8 | use integer; # see below in _replaceNextLargerWith() for mod to make
|
---|
9 | # if you don't use this
|
---|
10 | require Exporter;
|
---|
11 | @ISA = qw(Exporter);
|
---|
12 | @EXPORT = qw();
|
---|
13 | @EXPORT_OK = qw(LCS diff traverse_sequences);
|
---|
14 | $VERSION = 1.10; # manually tracking Algorithm::Diff
|
---|
15 |
|
---|
16 | # McIlroy-Hunt diff algorithm
|
---|
17 | # Adapted from the Smalltalk code of Mario I. Wolczko, <[email protected]>
|
---|
18 | # by Ned Konz, [email protected]
|
---|
19 |
|
---|
20 | =head1 NAME
|
---|
21 |
|
---|
22 | Algorithm::DiffOld - Compute `intelligent' differences between two files / lists
|
---|
23 | but use the old (<=0.59) interface.
|
---|
24 |
|
---|
25 | =head1 NOTE
|
---|
26 |
|
---|
27 | This has been provided as part of the Algorithm::Diff package by Ned Konz.
|
---|
28 | This particular module is B<ONLY> for people who B<HAVE> to have the old
|
---|
29 | interface, which uses a comparison function rather than a key generating
|
---|
30 | function.
|
---|
31 |
|
---|
32 | Because each of the lines in one array have to be compared with each
|
---|
33 | of the lines in the other array, this does M*N comparisions. This can
|
---|
34 | be very slow. I clocked it at taking 18 times as long as the stock
|
---|
35 | version of Algorithm::Diff for a 4000-line file. It will get worse
|
---|
36 | quadratically as array sizes increase.
|
---|
37 |
|
---|
38 | =head1 SYNOPSIS
|
---|
39 |
|
---|
40 | use Algorithm::DiffOld qw(diff LCS traverse_sequences);
|
---|
41 |
|
---|
42 | @lcs = LCS( \@seq1, \@seq2, $comparison_function );
|
---|
43 |
|
---|
44 | $lcsref = LCS( \@seq1, \@seq2, $comparison_function );
|
---|
45 |
|
---|
46 | @diffs = diff( \@seq1, \@seq2, $comparison_function );
|
---|
47 |
|
---|
48 | traverse_sequences( \@seq1, \@seq2,
|
---|
49 | { MATCH => $callback,
|
---|
50 | DISCARD_A => $callback,
|
---|
51 | DISCARD_B => $callback,
|
---|
52 | },
|
---|
53 | $comparison_function );
|
---|
54 |
|
---|
55 | =head1 COMPARISON FUNCTIONS
|
---|
56 |
|
---|
57 | Each of the main routines should be passed a comparison function. If you
|
---|
58 | aren't passing one in, B<use Algorithm::Diff instead>.
|
---|
59 |
|
---|
60 | These functions should return a true value when two items should compare
|
---|
61 | as equal.
|
---|
62 |
|
---|
63 | For instance,
|
---|
64 |
|
---|
65 | @lcs = LCS( \@seq1, \@seq2, sub { my ($a, $b) = @_; $a eq $b } );
|
---|
66 |
|
---|
67 | but if that is all you're doing with your comparison function, just use
|
---|
68 | Algorithm::Diff and let it do this (this is its default).
|
---|
69 |
|
---|
70 | Or:
|
---|
71 |
|
---|
72 | sub someFunkyComparisonFunction
|
---|
73 | {
|
---|
74 | my ($a, $b) = @_;
|
---|
75 | $a =~ m{$b};
|
---|
76 | }
|
---|
77 |
|
---|
78 | @diffs = diff( \@lines, \@patterns, \&someFunkyComparisonFunction );
|
---|
79 |
|
---|
80 | which would allow you to diff an array @lines which consists of text
|
---|
81 | lines with an array @patterns which consists of regular expressions.
|
---|
82 |
|
---|
83 | This is actually the reason I wrote this version -- there is no way
|
---|
84 | to do this with a key generation function as in the stock Algorithm::Diff.
|
---|
85 |
|
---|
86 | =cut
|
---|
87 |
|
---|
88 | # Find the place at which aValue would normally be inserted into the array. If
|
---|
89 | # that place is already occupied by aValue, do nothing, and return undef. If
|
---|
90 | # the place does not exist (i.e., it is off the end of the array), add it to
|
---|
91 | # the end, otherwise replace the element at that point with aValue.
|
---|
92 | # It is assumed that the array's values are numeric.
|
---|
93 | # This is where the bulk (75%) of the time is spent in this module, so try to
|
---|
94 | # make it fast!
|
---|
95 |
|
---|
96 | sub _replaceNextLargerWith
|
---|
97 | {
|
---|
98 | my ( $array, $aValue, $high ) = @_;
|
---|
99 | $high ||= $#$array;
|
---|
100 |
|
---|
101 | # off the end?
|
---|
102 | if ( $high == -1 || $aValue > $array->[ -1 ] )
|
---|
103 | {
|
---|
104 | push( @$array, $aValue );
|
---|
105 | return $high + 1;
|
---|
106 | }
|
---|
107 |
|
---|
108 | # binary search for insertion point...
|
---|
109 | my $low = 0;
|
---|
110 | my $index;
|
---|
111 | my $found;
|
---|
112 | while ( $low <= $high )
|
---|
113 | {
|
---|
114 | $index = ( $high + $low ) / 2;
|
---|
115 | # $index = int(( $high + $low ) / 2); # without 'use integer'
|
---|
116 | $found = $array->[ $index ];
|
---|
117 |
|
---|
118 | if ( $aValue == $found )
|
---|
119 | {
|
---|
120 | return undef;
|
---|
121 | }
|
---|
122 | elsif ( $aValue > $found )
|
---|
123 | {
|
---|
124 | $low = $index + 1;
|
---|
125 | }
|
---|
126 | else
|
---|
127 | {
|
---|
128 | $high = $index - 1;
|
---|
129 | }
|
---|
130 | }
|
---|
131 |
|
---|
132 | # now insertion point is in $low.
|
---|
133 | $array->[ $low ] = $aValue; # overwrite next larger
|
---|
134 | return $low;
|
---|
135 | }
|
---|
136 |
|
---|
137 | # This method computes the longest common subsequence in $a and $b.
|
---|
138 |
|
---|
139 | # Result is array or ref, whose contents is such that
|
---|
140 | # $a->[ $i ] == $b->[ $result[ $i ] ]
|
---|
141 | # foreach $i in ( 0 .. $#result ) if $result[ $i ] is defined.
|
---|
142 |
|
---|
143 | # An additional argument may be passed; this is a CODE ref to a comparison
|
---|
144 | # routine. By default, comparisons will use "eq" .
|
---|
145 | # Note that this routine will be called as many as M*N times, so make it fast!
|
---|
146 |
|
---|
147 | # Additional parameters, if any, will be passed to the key generation routine.
|
---|
148 |
|
---|
149 | sub _longestCommonSubsequence
|
---|
150 | {
|
---|
151 | my $a = shift; # array ref
|
---|
152 | my $b = shift; # array ref
|
---|
153 | my $compare = shift || sub { my $a = shift; my $b = shift; $a eq $b };
|
---|
154 |
|
---|
155 | my $aStart = 0;
|
---|
156 | my $aFinish = $#$a;
|
---|
157 | my $bStart = 0;
|
---|
158 | my $bFinish = $#$b;
|
---|
159 | my $matchVector = [];
|
---|
160 |
|
---|
161 | # First we prune off any common elements at the beginning
|
---|
162 | while ( $aStart <= $aFinish
|
---|
163 | and $bStart <= $bFinish
|
---|
164 | and &$compare( $a->[ $aStart ], $b->[ $bStart ], @_ ) )
|
---|
165 | {
|
---|
166 | $matchVector->[ $aStart++ ] = $bStart++;
|
---|
167 | }
|
---|
168 |
|
---|
169 | # now the end
|
---|
170 | while ( $aStart <= $aFinish
|
---|
171 | and $bStart <= $bFinish
|
---|
172 | and &$compare( $a->[ $aFinish ], $b->[ $bFinish ], @_ ) )
|
---|
173 | {
|
---|
174 | $matchVector->[ $aFinish-- ] = $bFinish--;
|
---|
175 | }
|
---|
176 |
|
---|
177 | my $thresh = [];
|
---|
178 | my $links = [];
|
---|
179 |
|
---|
180 | my ( $i, $ai, $j, $k );
|
---|
181 | for ( $i = $aStart; $i <= $aFinish; $i++ )
|
---|
182 | {
|
---|
183 | $k = 0;
|
---|
184 | # look for each element of @b between $bStart and $bFinish
|
---|
185 | # that matches $a->[ $i ], in reverse order
|
---|
186 | for ($j = $bFinish; $j >= $bStart; $j--)
|
---|
187 | {
|
---|
188 | next if ! &$compare( $a->[$i], $b->[$j] );
|
---|
189 | # optimization: most of the time this will be true
|
---|
190 | if ( $k
|
---|
191 | and $thresh->[ $k ] > $j
|
---|
192 | and $thresh->[ $k - 1 ] < $j )
|
---|
193 | {
|
---|
194 | $thresh->[ $k ] = $j;
|
---|
195 | }
|
---|
196 | else
|
---|
197 | {
|
---|
198 | $k = _replaceNextLargerWith( $thresh, $j, $k );
|
---|
199 | }
|
---|
200 |
|
---|
201 | # oddly, it's faster to always test this (CPU cache?).
|
---|
202 | if ( defined( $k ) )
|
---|
203 | {
|
---|
204 | $links->[ $k ] =
|
---|
205 | [ ( $k ? $links->[ $k - 1 ] : undef ), $i, $j ];
|
---|
206 | }
|
---|
207 | }
|
---|
208 | }
|
---|
209 |
|
---|
210 | if ( @$thresh )
|
---|
211 | {
|
---|
212 | for ( my $link = $links->[ $#$thresh ]; $link; $link = $link->[ 0 ] )
|
---|
213 | {
|
---|
214 | $matchVector->[ $link->[ 1 ] ] = $link->[ 2 ];
|
---|
215 | }
|
---|
216 | }
|
---|
217 |
|
---|
218 | return wantarray ? @$matchVector : $matchVector;
|
---|
219 | }
|
---|
220 |
|
---|
221 | sub traverse_sequences
|
---|
222 | {
|
---|
223 | my $a = shift; # array ref
|
---|
224 | my $b = shift; # array ref
|
---|
225 | my $callbacks = shift || { };
|
---|
226 | my $compare = shift;
|
---|
227 | my $matchCallback = $callbacks->{'MATCH'} || sub { };
|
---|
228 | my $discardACallback = $callbacks->{'DISCARD_A'} || sub { };
|
---|
229 | my $finishedACallback = $callbacks->{'A_FINISHED'};
|
---|
230 | my $discardBCallback = $callbacks->{'DISCARD_B'} || sub { };
|
---|
231 | my $finishedBCallback = $callbacks->{'B_FINISHED'};
|
---|
232 | my $matchVector = _longestCommonSubsequence( $a, $b, $compare, @_ );
|
---|
233 | # Process all the lines in match vector
|
---|
234 | my $lastA = $#$a;
|
---|
235 | my $lastB = $#$b;
|
---|
236 | my $bi = 0;
|
---|
237 | my $ai;
|
---|
238 | for ( $ai = 0; $ai <= $#$matchVector; $ai++ )
|
---|
239 | {
|
---|
240 | my $bLine = $matchVector->[ $ai ];
|
---|
241 | if ( defined( $bLine ) ) # matched
|
---|
242 | {
|
---|
243 | &$discardBCallback( $ai, $bi++, @_ ) while $bi < $bLine;
|
---|
244 | &$matchCallback( $ai, $bi++, @_ );
|
---|
245 | }
|
---|
246 | else
|
---|
247 | {
|
---|
248 | &$discardACallback( $ai, $bi, @_ );
|
---|
249 | }
|
---|
250 | }
|
---|
251 | # the last entry (if any) processed was a match.
|
---|
252 |
|
---|
253 | if ( defined( $finishedBCallback ) && $ai <= $lastA )
|
---|
254 | {
|
---|
255 | &$finishedBCallback( $bi, @_ );
|
---|
256 | }
|
---|
257 | else
|
---|
258 | {
|
---|
259 | &$discardACallback( $ai++, $bi, @_ ) while ( $ai <= $lastA );
|
---|
260 | }
|
---|
261 |
|
---|
262 | if ( defined( $finishedACallback ) && $bi <= $lastB )
|
---|
263 | {
|
---|
264 | &$finishedACallback( $ai, @_ );
|
---|
265 | }
|
---|
266 | else
|
---|
267 | {
|
---|
268 | &$discardBCallback( $ai, $bi++, @_ ) while ( $bi <= $lastB );
|
---|
269 | }
|
---|
270 | return 1;
|
---|
271 | }
|
---|
272 |
|
---|
273 | sub LCS
|
---|
274 | {
|
---|
275 | my $a = shift; # array ref
|
---|
276 | my $matchVector = _longestCommonSubsequence( $a, @_ );
|
---|
277 | my @retval;
|
---|
278 | my $i;
|
---|
279 | for ( $i = 0; $i <= $#$matchVector; $i++ )
|
---|
280 | {
|
---|
281 | if ( defined( $matchVector->[ $i ] ) )
|
---|
282 | {
|
---|
283 | push( @retval, $a->[ $i ] );
|
---|
284 | }
|
---|
285 | }
|
---|
286 | return wantarray ? @retval : \@retval;
|
---|
287 | }
|
---|
288 |
|
---|
289 | sub diff
|
---|
290 | {
|
---|
291 | my $a = shift; # array ref
|
---|
292 | my $b = shift; # array ref
|
---|
293 | my $retval = [];
|
---|
294 | my $hunk = [];
|
---|
295 | my $discard = sub { push( @$hunk, [ '-', $_[ 0 ], $a->[ $_[ 0 ] ] ] ) };
|
---|
296 | my $add = sub { push( @$hunk, [ '+', $_[ 1 ], $b->[ $_[ 1 ] ] ] ) };
|
---|
297 | my $match = sub { push( @$retval, $hunk ) if scalar(@$hunk); $hunk = [] };
|
---|
298 | traverse_sequences( $a, $b,
|
---|
299 | { MATCH => $match, DISCARD_A => $discard, DISCARD_B => $add },
|
---|
300 | @_ );
|
---|
301 | &$match();
|
---|
302 | return wantarray ? @$retval : $retval;
|
---|
303 | }
|
---|
304 |
|
---|
305 | 1;
|
---|