| 1 | #!/usr/bin/perl -w
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| 2 | #
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| 3 | # `Diff' program in Perl
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| 4 | # Copyright 1998 M-J. Dominus. ([email protected])
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| 5 | #
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| 6 | # This program is free software; you can redistribute it and/or modify it
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| 7 | # under the same terms as Perl itself.
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| 8 | #
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| 9 | # Altered to output in `context diff' format (but without context)
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| 10 | # September 1998 Christian Murphy ([email protected])
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| 11 | #
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| 12 | # Command-line arguments and context lines feature added
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| 13 | # September 1998 Amir D. Karger ([email protected])
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| 14 | #
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| 15 | # In this file, "item" usually means "line of text", and "item number" usually
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| 16 | # means "line number". But theoretically the code could be used more generally
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| 17 | use strict;
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| 18 |
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| 19 | use Algorithm::Diff qw(diff);
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| 20 | use File::stat;
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| 21 | use vars qw ($opt_C $opt_c $opt_u $opt_U);
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| 22 | use Getopt::Std;
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| 23 |
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| 24 | my $usage = << "ENDUSAGE";
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| 25 | Usage: $0 [{-c | -u}] [{-C | -U} lines] oldfile newfile
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| 26 | -c will do a context diff with 3 lines of context
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| 27 | -C will do a context diff with 'lines' lines of context
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| 28 | -u will do a unified diff with 3 lines of context
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| 29 | -U will do a unified diff with 'lines' lines of context
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| 30 | ENDUSAGE
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| 31 |
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| 32 | getopts('U:C:cu') or bag("$usage");
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| 33 | bag("$usage") unless @ARGV == 2;
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| 34 | my ($file1, $file2) = @ARGV;
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| 35 | if (defined $opt_C || defined $opt_c) {
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| 36 | $opt_c = ""; # -c on if -C given on command line
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| 37 | $opt_u = undef;
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| 38 | } elsif (defined $opt_U || defined $opt_u) {
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| 39 | $opt_u = ""; # -u on if -U given on command line
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| 40 | $opt_c = undef;
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| 41 | } else {
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| 42 | $opt_c = ""; # by default, do context diff, not old diff
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| 43 | }
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| 44 |
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| 45 | my ($char1, $char2); # string to print before file names
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| 46 | my $Context_Lines; # lines of context to print
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| 47 | if (defined $opt_c) {
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| 48 | $Context_Lines = defined $opt_C ? $opt_C : 3;
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| 49 | $char1 = '*' x 3; $char2 = '-' x 3;
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| 50 | } elsif (defined $opt_u) {
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| 51 | $Context_Lines = defined $opt_U ? $opt_U : 3;
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| 52 | $char1 = '-' x 3; $char2 = '+' x 3;
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| 53 | }
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| 54 |
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| 55 | # After we've read up to a certain point in each file, the number of items
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| 56 | # we've read from each file will differ by $FLD (could be 0)
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| 57 | my $File_Length_Difference = 0;
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| 58 |
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| 59 | open (F1, $file1) or bag("Couldn't open $file1: $!");
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| 60 | open (F2, $file2) or bag("Couldn't open $file2: $!");
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| 61 | my (@f1, @f2);
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| 62 | chomp(@f1 = <F1>);
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| 63 | close F1;
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| 64 | chomp(@f2 = <F2>);
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| 65 | close F2;
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| 66 |
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| 67 | # diff yields lots of pieces, each of which is basically a Block object
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| 68 | my $diffs = diff(\@f1, \@f2);
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| 69 | exit 0 unless @$diffs;
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| 70 |
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| 71 | my $st = stat($file1);
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| 72 | print "$char1 $file1\t", scalar localtime($st->mtime), "\n";
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| 73 | $st = stat($file2);
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| 74 | print "$char2 $file2\t", scalar localtime($st->mtime), "\n";
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| 75 |
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| 76 | my ($hunk,$oldhunk);
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| 77 | # Loop over hunks. If a hunk overlaps with the last hunk, join them.
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| 78 | # Otherwise, print out the old one.
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| 79 | foreach my $piece (@$diffs) {
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| 80 | $hunk = new Hunk ($piece, $Context_Lines);
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| 81 | next unless $oldhunk;
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| 82 |
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| 83 | if ($hunk->does_overlap($oldhunk)) {
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| 84 | $hunk->prepend_hunk($oldhunk);
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| 85 | } else {
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| 86 | $oldhunk->output_diff(\@f1, \@f2);
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| 87 | }
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| 88 |
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| 89 | } continue {
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| 90 | $oldhunk = $hunk;
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| 91 | }
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| 92 |
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| 93 | # print the last hunk
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| 94 | $oldhunk->output_diff(\@f1, \@f2);
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| 95 | exit 1;
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| 96 | # END MAIN PROGRAM
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| 97 |
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| 98 | sub bag {
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| 99 | my $msg = shift;
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| 100 | $msg .= "\n";
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| 101 | warn $msg;
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| 102 | exit 2;
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| 103 | }
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| 104 |
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| 105 | # Package Hunk. A Hunk is a group of Blocks which overlap because of the
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| 106 | # context surrounding each block. (So if we're not using context, every
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| 107 | # hunk will contain one block.)
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| 108 | {
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| 109 | package Hunk;
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| 110 |
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| 111 | sub new {
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| 112 | # Arg1 is output from &LCS::diff (which corresponds to one Block)
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| 113 | # Arg2 is the number of items (lines, e.g.,) of context around each block
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| 114 | #
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| 115 | # This subroutine changes $File_Length_Difference
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| 116 | #
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| 117 | # Fields in a Hunk:
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| 118 | # blocks - a list of Block objects
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| 119 | # start - index in file 1 where first block of the hunk starts
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| 120 | # end - index in file 1 where last block of the hunk ends
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| 121 | #
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| 122 | # Variables:
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| 123 | # before_diff - how much longer file 2 is than file 1 due to all hunks
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| 124 | # until but NOT including this one
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| 125 | # after_diff - difference due to all hunks including this one
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| 126 | my ($class, $piece, $context_items) = @_;
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| 127 |
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| 128 | my $block = new Block ($piece); # this modifies $FLD!
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| 129 |
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| 130 | my $before_diff = $File_Length_Difference; # BEFORE this hunk
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| 131 | my $after_diff = $before_diff + $block->{"length_diff"};
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| 132 | $File_Length_Difference += $block->{"length_diff"};
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| 133 |
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| 134 | # @remove_array and @insert_array hold the items to insert and remove
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| 135 | # Save the start & beginning of each array. If the array doesn't exist
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| 136 | # though (e.g., we're only adding items in this block), then figure
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| 137 | # out the line number based on the line number of the other file and
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| 138 | # the current difference in file lenghts
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| 139 | my @remove_array = $block->remove;
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| 140 | my @insert_array = $block->insert;
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| 141 | my ($a1, $a2, $b1, $b2, $start1, $start2, $end1, $end2);
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| 142 | $a1 = @remove_array ? $remove_array[0 ]->{"item_no"} : -1;
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| 143 | $a2 = @remove_array ? $remove_array[-1]->{"item_no"} : -1;
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| 144 | $b1 = @insert_array ? $insert_array[0 ]->{"item_no"} : -1;
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| 145 | $b2 = @insert_array ? $insert_array[-1]->{"item_no"} : -1;
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| 146 |
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| 147 | $start1 = $a1 == -1 ? $b1 - $before_diff : $a1;
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| 148 | $end1 = $a2 == -1 ? $b2 - $after_diff : $a2;
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| 149 | $start2 = $b1 == -1 ? $a1 + $before_diff : $b1;
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| 150 | $end2 = $b2 == -1 ? $a2 + $after_diff : $b2;
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| 151 |
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| 152 | # At first, a hunk will have just one Block in it
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| 153 | my $hunk = {
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| 154 | "start1" => $start1,
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| 155 | "start2" => $start2,
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| 156 | "end1" => $end1,
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| 157 | "end2" => $end2,
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| 158 | "blocks" => [$block],
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| 159 | };
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| 160 | bless $hunk, $class;
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| 161 |
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| 162 | $hunk->flag_context($context_items);
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| 163 |
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| 164 | return $hunk;
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| 165 | }
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| 166 |
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| 167 | # Change the "start" and "end" fields to note that context should be added
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| 168 | # to this hunk
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| 169 | sub flag_context {
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| 170 | my ($hunk, $context_items) = @_;
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| 171 | return unless $context_items; # no context
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| 172 |
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| 173 | # add context before
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| 174 | my $start1 = $hunk->{"start1"};
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| 175 | my $num_added = $context_items > $start1 ? $start1 : $context_items;
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| 176 | $hunk->{"start1"} -= $num_added;
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| 177 | $hunk->{"start2"} -= $num_added;
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| 178 |
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| 179 | # context after
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| 180 | my $end1 = $hunk->{"end1"};
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| 181 | $num_added = ($end1+$context_items > $#f1) ?
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| 182 | $#f1 - $end1 :
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| 183 | $context_items;
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| 184 | $hunk->{"end1"} += $num_added;
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| 185 | $hunk->{"end2"} += $num_added;
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| 186 | }
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| 187 |
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| 188 | # Is there an overlap between hunk arg0 and old hunk arg1?
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| 189 | # Note: if end of old hunk is one less than beginning of second, they overlap
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| 190 | sub does_overlap {
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| 191 | my ($hunk, $oldhunk) = @_;
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| 192 | return "" unless $oldhunk; # first time through, $oldhunk is empty
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| 193 |
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| 194 | # Do I actually need to test both?
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| 195 | return ($hunk->{"start1"} - $oldhunk->{"end1"} <= 1 ||
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| 196 | $hunk->{"start2"} - $oldhunk->{"end2"} <= 1);
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| 197 | }
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| 198 |
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| 199 | # Prepend hunk arg1 to hunk arg0
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| 200 | # Note that arg1 isn't updated! Only arg0 is.
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| 201 | sub prepend_hunk {
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| 202 | my ($hunk, $oldhunk) = @_;
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| 203 |
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| 204 | $hunk->{"start1"} = $oldhunk->{"start1"};
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| 205 | $hunk->{"start2"} = $oldhunk->{"start2"};
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| 206 |
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| 207 | unshift (@{$hunk->{"blocks"}}, @{$oldhunk->{"blocks"}});
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| 208 | }
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| 209 |
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| 210 |
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| 211 | # DIFF OUTPUT ROUTINES. THESE ROUTINES CONTAIN DIFF FORMATTING INFO...
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| 212 | sub output_diff {
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| 213 | if (defined $main::opt_u) {&output_unified_diff(@_)}
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| 214 | elsif (defined $main::opt_c) {&output_context_diff(@_)}
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| 215 | else {die "unknown diff"}
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| 216 | }
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| 217 |
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| 218 | sub output_unified_diff {
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| 219 | my ($hunk, $fileref1, $fileref2) = @_;
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| 220 | my @blocklist;
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| 221 |
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| 222 | # Calculate item number range.
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| 223 | my $range1 = $hunk->unified_range(1);
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| 224 | my $range2 = $hunk->unified_range(2);
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| 225 | print "@@ -$range1 +$range2 @@\n";
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| 226 |
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| 227 | # Outlist starts containing the hunk of file 1.
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| 228 | # Removing an item just means putting a '-' in front of it.
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| 229 | # Inserting an item requires getting it from file2 and splicing it in.
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| 230 | # We splice in $num_added items. Remove blocks use $num_added because
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| 231 | # splicing changed the length of outlist.
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| 232 | # We remove $num_removed items. Insert blocks use $num_removed because
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| 233 | # their item numbers---corresponding to positions in file *2*--- don't take
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| 234 | # removed items into account.
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| 235 | my $low = $hunk->{"start1"};
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| 236 | my $hi = $hunk->{"end1"};
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| 237 | my ($num_added, $num_removed) = (0,0);
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| 238 | my @outlist = @$fileref1[$low..$hi];
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| 239 | map {s/^/ /} @outlist; # assume it's just context
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| 240 |
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| 241 | foreach my $block (@{$hunk->{"blocks"}}) {
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| 242 | foreach my $item ($block->remove) {
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| 243 | my $op = $item->{"sign"}; # -
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| 244 | my $offset = $item->{"item_no"} - $low + $num_added;
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| 245 | $outlist[$offset] =~ s/^ /$op/;
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| 246 | $num_removed++;
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| 247 | }
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| 248 | foreach my $item ($block->insert) {
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| 249 | my $op = $item->{"sign"}; # +
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| 250 | my $i = $item->{"item_no"};
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| 251 | my $offset = $i - $hunk->{"start2"} + $num_removed;
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| 252 | splice(@outlist,$offset,0,"$op$$fileref2[$i]");
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| 253 | $num_added++;
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| 254 | }
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| 255 | }
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| 256 |
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| 257 | map {s/$/\n/} @outlist; # add \n's
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| 258 | print @outlist;
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| 259 |
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| 260 | }
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| 261 |
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| 262 | sub output_context_diff {
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| 263 | my ($hunk, $fileref1, $fileref2) = @_;
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| 264 | my @blocklist;
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| 265 |
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| 266 | print "***************\n";
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| 267 | # Calculate item number range.
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| 268 | my $range1 = $hunk->context_range(1);
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| 269 | my $range2 = $hunk->context_range(2);
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| 270 |
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| 271 | # Print out file 1 part for each block in context diff format if there are
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| 272 | # any blocks that remove items
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| 273 | print "*** $range1 ****\n";
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| 274 | my $low = $hunk->{"start1"};
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| 275 | my $hi = $hunk->{"end1"};
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| 276 | if (@blocklist = grep {$_->remove} @{$hunk->{"blocks"}}) {
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| 277 | my @outlist = @$fileref1[$low..$hi];
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| 278 | map {s/^/ /} @outlist; # assume it's just context
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| 279 | foreach my $block (@blocklist) {
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| 280 | my $op = $block->op; # - or !
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| 281 | foreach my $item ($block->remove) {
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| 282 | $outlist[$item->{"item_no"} - $low] =~ s/^ /$op/;
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| 283 | }
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| 284 | }
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| 285 | map {s/$/\n/} @outlist; # add \n's
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| 286 | print @outlist;
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| 287 | }
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| 288 |
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| 289 | print "--- $range2 ----\n";
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| 290 | $low = $hunk->{"start2"};
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| 291 | $hi = $hunk->{"end2"};
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| 292 | if (@blocklist = grep {$_->insert} @{$hunk->{"blocks"}}) {
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| 293 | my @outlist = @$fileref2[$low..$hi];
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| 294 | map {s/^/ /} @outlist; # assume it's just context
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| 295 | foreach my $block (@blocklist) {
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| 296 | my $op = $block->op; # + or !
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| 297 | foreach my $item ($block->insert) {
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| 298 | $outlist[$item->{"item_no"} - $low] =~ s/^ /$op/;
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| 299 | }
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| 300 | }
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| 301 | map {s/$/\n/} @outlist; # add \n's
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| 302 | print @outlist;
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| 303 | }
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| 304 | }
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| 305 |
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| 306 | sub context_range {
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| 307 | # Generate a range of item numbers to print. Only print 1 number if the range
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| 308 | # has only one item in it. Otherwise, it's 'start,end'
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| 309 | my ($hunk, $flag) = @_;
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| 310 | my ($start, $end) = ($hunk->{"start$flag"},$hunk->{"end$flag"});
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| 311 | $start++; $end++; # index from 1, not zero
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| 312 | my $range = ($start < $end) ? "$start,$end" : $end;
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| 313 | return $range;
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| 314 | }
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| 315 |
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| 316 | sub unified_range {
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| 317 | # Generate a range of item numbers to print for unified diff
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| 318 | # Print number where block starts, followed by number of lines in the block
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| 319 | # (don't print number of lines if it's 1)
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| 320 | my ($hunk, $flag) = @_;
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| 321 | my ($start, $end) = ($hunk->{"start$flag"},$hunk->{"end$flag"});
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| 322 | $start++; $end++; # index from 1, not zero
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| 323 | my $length = $end - $start + 1;
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| 324 | my $first = $length < 2 ? $end : $start; # strange, but correct...
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| 325 | my $range = $length== 1 ? $first : "$first,$length";
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| 326 | return $range;
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| 327 | }
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| 328 | } # end Package Hunk
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| 329 |
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| 330 | # Package Block. A block is an operation removing, adding, or changing
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| 331 | # a group of items. Basically, this is just a list of changes, where each
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| 332 | # change adds or deletes a single item.
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| 333 | # (Change could be a separate class, but it didn't seem worth it)
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| 334 | {
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| 335 | package Block;
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| 336 | sub new {
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| 337 | # Input is a chunk from &Algorithm::LCS::diff
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| 338 | # Fields in a block:
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| 339 | # length_diff - how much longer file 2 is than file 1 due to this block
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| 340 | # Each change has:
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| 341 | # sign - '+' for insert, '-' for remove
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| 342 | # item_no - number of the item in the file (e.g., line number)
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| 343 | # We don't bother storing the text of the item
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| 344 | #
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| 345 | my ($class,$chunk) = @_;
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| 346 | my @changes = ();
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| 347 |
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| 348 | # This just turns each change into a hash.
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| 349 | foreach my $item (@$chunk) {
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| 350 | my ($sign, $item_no, $text) = @$item;
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| 351 | my $hashref = {"sign" => $sign, "item_no" => $item_no};
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| 352 | push @changes, $hashref;
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| 353 | }
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| 354 |
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| 355 | my $block = { "changes" => \@changes };
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| 356 | bless $block, $class;
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| 357 |
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| 358 | $block->{"length_diff"} = $block->insert - $block->remove;
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| 359 | return $block;
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| 360 | }
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| 361 |
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| 362 |
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| 363 | # LOW LEVEL FUNCTIONS
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| 364 | sub op {
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| 365 | # what kind of block is this?
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| 366 | my $block = shift;
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| 367 | my $insert = $block->insert;
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| 368 | my $remove = $block->remove;
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| 369 |
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| 370 | $remove && $insert and return '!';
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| 371 | $remove and return '-';
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| 372 | $insert and return '+';
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| 373 | warn "unknown block type";
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| 374 | return '^'; # context block
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| 375 | }
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| 376 |
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| 377 | # Returns a list of the changes in this block that remove items
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| 378 | # (or the number of removals if called in scalar context)
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| 379 | sub remove { return grep {$_->{"sign"} eq '-'} @{shift->{"changes"}}; }
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| 380 |
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| 381 | # Returns a list of the changes in this block that insert items
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| 382 | sub insert { return grep {$_->{"sign"} eq '+'} @{shift->{"changes"}}; }
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| 383 |
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| 384 | } # end of package Block
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| 385 |
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