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#!/usr/bin/perl
#
# `Diff' program in Perl
# Copyright 1998 M-J. Dominus. (mjd-perl-diff@plover.com)
#
# This program is free software; you can redistribute it and/or modify it
# under the same terms as Perl itself.
#
# Altered to output in `context diff' format (but without context)
# September 1998 Christian Murphy (cpm@muc.de)
#
# Context lines feature added
# Unified, "Old" (Standard UNIX), Ed diff added September 1998
# Reverse_Ed (-f option) added March 1999
# Amir D. Karger (karger@bead.aecom.yu.edu)
#
# Modular functions integrated into program
# February 1999 M-J. Dominus (mjd-perl-diff@plover.com)
#
# In this file, "item" usually means "line of text", and "item number" usually
# means "line number". But theoretically the code could be used more generally
use strict;
use Algorithm::Diff qw(diff);
# GLOBAL VARIABLES ####
# After we've read up to a certain point in each file, the number of items
# we've read from each file will differ by $FLD (could be 0)
my $File_Length_Difference = 0;
#ed diff outputs hunks *backwards*, so we need to save hunks when doing ed diff
my @Ed_Hunks = ();
########################
my $usage = << "ENDUSAGE";
Usage: $0 [{-c | -C lines -e | -f | -u | -U lines |-q | -i | -w}] oldfile newfile
-c do a context diff with 3 lines of context
-C do a context diff with 'lines' lines of context (implies -c)
-e create a script for the ed editor to change oldfile to newfile
-f like -e but in reverse order
-u do a unified diff with 3 lines of context
-U do a unified diff with 'lines' lines of context (implies -u)
-q report only whether or not the files differ
-i ignore differences in Upper/lower-case
-w ignore differences in white-space (space and TAB characters)
By default it will do an "old-style" diff, with output like UNIX diff
ENDUSAGE
my $Context_Lines = 0; # lines of context to print. 0 for old-style diff
my $Diff_Type = "OLD"; # by default, do standard UNIX diff
my ($opt_c, $opt_u, $opt_e, $opt_f, $opt_q, $opt_i, $opt_w);
my $compareRoutineRef = undef;
while ($ARGV[0] =~ /^-/) {
my $opt = shift;
last if $opt eq '--';
if ($opt =~ /^-C(.*)/) {
$Context_Lines = $1 || shift;
$opt_c = 1;
$Diff_Type = "CONTEXT";
} elsif ($opt =~ /^-c$/) {
$Context_Lines = 3;
$opt_c = 1;
$Diff_Type = "CONTEXT";
} elsif ($opt =~ /^-e$/) {
$opt_e = 1;
$Diff_Type = "ED";
} elsif ($opt =~ /^-f$/) {
$opt_f = 1;
$Diff_Type = "REVERSE_ED";
} elsif ($opt =~ /^-U(.*)$/) {
$Context_Lines = $1 || shift;
$opt_u = 1;
$Diff_Type = "UNIFIED";
} elsif ($opt =~ /^-u$/) {
$Context_Lines = 3;
$opt_u = 1;
$Diff_Type = "UNIFIED";
} elsif ($opt =~ /^-q$/) {
$Context_Lines = 0;
$opt_q = 1;
$opt_e = 1;
$Diff_Type = "ED";
} elsif ($opt =~ /^-i$/) {
$opt_i = 1;
$compareRoutineRef = \&compareRoutine;
} elsif ($opt =~ /^-w$/) {
$opt_w = 1;
$compareRoutineRef = \&compareRoutine;
} else {
$opt =~ s/^-//;
bag("Illegal option -- $opt");
}
}
if ($opt_q and grep($_,($opt_c, $opt_f, $opt_u)) > 1) {
bag("Combining -q with other options is nonsensical");
}
if (grep($_,($opt_c, $opt_e, $opt_f, $opt_u)) > 1) {
bag("Only one of -c, -u, -f, -e are allowed");
}
bag($usage) unless @ARGV == 2;
######## DO THE DIFF!
my ($file1, $file2) = @ARGV;
my ($char1, $char2); # string to print before file names
if ($Diff_Type eq "CONTEXT") {
$char1 = '*' x 3; $char2 = '-' x 3;
} elsif ($Diff_Type eq "UNIFIED") {
$char1 = '-' x 3; $char2 = '+' x 3;
}
open (F1, $file1) or bag("Couldn't open $file1: $!");
open (F2, $file2) or bag("Couldn't open $file2: $!");
my (@f1, @f2);
chomp(@f1 = <F1>);
close F1;
chomp(@f2 = <F2>);
close F2;
# diff yields lots of pieces, each of which is basically a Block object
my $diffs = diff(\@f1, \@f2, $compareRoutineRef);
exit 0 unless @$diffs;
if ($opt_q and @$diffs) {
print "Files $file1 and $file2 differ\n";
exit 1;
}
if ($Diff_Type =~ /UNIFIED|CONTEXT/) {
my @st = stat($file1);
my $MTIME = 9;
print "$char1 $file1\t", scalar localtime($st[$MTIME]), "\n";
@st = stat($file2);
print "$char2 $file2\t", scalar localtime($st[$MTIME]), "\n";
}
my ($hunk,$oldhunk);
# Loop over hunks. If a hunk overlaps with the last hunk, join them.
# Otherwise, print out the old one.
foreach my $piece (@$diffs) {
$hunk = new Hunk ($piece, $Context_Lines);
next unless $oldhunk; # first time through
# Don't need to check for overlap if blocks have no context lines
if ($Context_Lines && $hunk->does_overlap($oldhunk)) {
$hunk->prepend_hunk($oldhunk);
} else {
$oldhunk->output_diff(\@f1, \@f2, $Diff_Type);
}
} continue {
$oldhunk = $hunk;
}
# print the last hunk
$oldhunk->output_diff(\@f1, \@f2, $Diff_Type);
# Print hunks backwards if we're doing an ed diff
map {$_->output_ed_diff(\@f1, \@f2, $Diff_Type)} @Ed_Hunks if @Ed_Hunks;
exit 1;
# END MAIN PROGRAM
sub bag {
my $msg = shift;
$msg .= "\n";
warn $msg;
exit 2;
}
sub compareRoutine {
my $line = shift;
$line =~ s/[ \t\r\n]+//g if ($opt_w);
$line = uc( $line ) if ($opt_i);
return $line;
}
########
# Package Hunk. A Hunk is a group of Blocks which overlap because of the
# context surrounding each block. (So if we're not using context, every
# hunk will contain one block.)
{
package Hunk;
sub new {
# Arg1 is output from &LCS::diff (which corresponds to one Block)
# Arg2 is the number of items (lines, e.g.,) of context around each block
#
# This subroutine changes $File_Length_Difference
#
# Fields in a Hunk:
# blocks - a list of Block objects
# start - index in file 1 where first block of the hunk starts
# end - index in file 1 where last block of the hunk ends
#
# Variables:
# before_diff - how much longer file 2 is than file 1 due to all hunks
# until but NOT including this one
# after_diff - difference due to all hunks including this one
my ($class, $piece, $context_items) = @_;
my $block = new Block ($piece); # this modifies $FLD!
my $before_diff = $File_Length_Difference; # BEFORE this hunk
my $after_diff = $before_diff + $block->{"length_diff"};
$File_Length_Difference += $block->{"length_diff"};
# @remove_array and @insert_array hold the items to insert and remove
# Save the start & beginning of each array. If the array doesn't exist
# though (e.g., we're only adding items in this block), then figure
# out the line number based on the line number of the other file and
# the current difference in file lengths
my @remove_array = $block->remove;
my @insert_array = $block->insert;
my ($a1, $a2, $b1, $b2, $start1, $start2, $end1, $end2);
$a1 = @remove_array ? $remove_array[0 ]->{"item_no"} : -1;
$a2 = @remove_array ? $remove_array[-1]->{"item_no"} : -1;
$b1 = @insert_array ? $insert_array[0 ]->{"item_no"} : -1;
$b2 = @insert_array ? $insert_array[-1]->{"item_no"} : -1;
$start1 = $a1 == -1 ? $b1 - $before_diff : $a1;
$end1 = $a2 == -1 ? $b2 - $after_diff : $a2;
$start2 = $b1 == -1 ? $a1 + $before_diff : $b1;
$end2 = $b2 == -1 ? $a2 + $after_diff : $b2;
# At first, a hunk will have just one Block in it
my $hunk = {
"start1" => $start1,
"start2" => $start2,
"end1" => $end1,
"end2" => $end2,
"blocks" => [$block],
};
bless $hunk, $class;
$hunk->flag_context($context_items);
return $hunk;
}
# Change the "start" and "end" fields to note that context should be added
# to this hunk
sub flag_context {
my ($hunk, $context_items) = @_;
return unless $context_items; # no context
# add context before
my $start1 = $hunk->{"start1"};
my $num_added = $context_items > $start1 ? $start1 : $context_items;
$hunk->{"start1"} -= $num_added;
$hunk->{"start2"} -= $num_added;
# context after
my $end1 = $hunk->{"end1"};
$num_added = ($end1+$context_items > $#f1) ?
$#f1 - $end1 :
$context_items;
$hunk->{"end1"} += $num_added;
$hunk->{"end2"} += $num_added;
}
# Is there an overlap between hunk arg0 and old hunk arg1?
# Note: if end of old hunk is one less than beginning of second, they overlap
sub does_overlap {
my ($hunk, $oldhunk) = @_;
return "" unless $oldhunk; # first time through, $oldhunk is empty
# Do I actually need to test both?
return ($hunk->{"start1"} - $oldhunk->{"end1"} <= 1 ||
$hunk->{"start2"} - $oldhunk->{"end2"} <= 1);
}
# Prepend hunk arg1 to hunk arg0
# Note that arg1 isn't updated! Only arg0 is.
sub prepend_hunk {
my ($hunk, $oldhunk) = @_;
$hunk->{"start1"} = $oldhunk->{"start1"};
$hunk->{"start2"} = $oldhunk->{"start2"};
unshift (@{$hunk->{"blocks"}}, @{$oldhunk->{"blocks"}});
}
# DIFF OUTPUT ROUTINES. THESE ROUTINES CONTAIN DIFF FORMATTING INFO...
sub output_diff {
# First arg is the current hunk of course
# Next args are refs to the files
# last arg is type of diff
my $diff_type = $_[-1];
my %funchash = ("OLD" => \&output_old_diff,
"CONTEXT" => \&output_context_diff,
"ED" => \&store_ed_diff,
"REVERSE_ED" => \&output_ed_diff,
"UNIFIED" => \&output_unified_diff,
);
if (exists $funchash{$diff_type}) {
&{$funchash{$diff_type}}(@_); # pass in all args
} else {die "unknown diff type $diff_type"}
}
sub output_old_diff {
# Note that an old diff can't have any context. Therefore, we know that
# there's only one block in the hunk.
my ($hunk, $fileref1, $fileref2) = @_;
my %op_hash = ('+' => 'a', '-' => 'd', '!' => 'c');
my @blocklist = @{$hunk->{"blocks"}};
warn ("Expecting one block in an old diff hunk!") if scalar @blocklist != 1;
my $block = $blocklist[0];
my $op = $block->op; # +, -, or !
# Calculate item number range.
# old diff range is just like a context diff range, except the ranges
# are on one line with the action between them.
my $range1 = $hunk->context_range(1);
my $range2 = $hunk->context_range(2);
my $action = $op_hash{$op} || warn "unknown op $op";
print "$range1$action$range2\n";
# If removing anything, just print out all the remove lines in the hunk
# which is just all the remove lines in the block
if ($block->remove) {
my @outlist = @$fileref1[$hunk->{"start1"}..$hunk->{"end1"}];
map {$_ = "< $_\n"} @outlist; # all lines will be '< text\n'
print @outlist;
}
print "---\n" if $op eq '!'; # only if inserting and removing
if ($block->insert) {
my @outlist = @$fileref2[$hunk->{"start2"}..$hunk->{"end2"}];
map {$_ = "> $_\n"} @outlist; # all lines will be '> text\n'
print @outlist;
}
}
sub output_unified_diff {
my ($hunk, $fileref1, $fileref2) = @_;
my @blocklist;
# Calculate item number range.
my $range1 = $hunk->unified_range(1);
my $range2 = $hunk->unified_range(2);
print "@@ -$range1 +$range2 @@\n";
# Outlist starts containing the hunk of file 1.
# Removing an item just means putting a '-' in front of it.
# Inserting an item requires getting it from file2 and splicing it in.
# We splice in $num_added items. Remove blocks use $num_added because
# splicing changed the length of outlist.
# We remove $num_removed items. Insert blocks use $num_removed because
# their item numbers---corresponding to positions in file *2*--- don't take
# removed items into account.
my $low = $hunk->{"start1"};
my $hi = $hunk->{"end1"};
my ($num_added, $num_removed) = (0,0);
my @outlist = @$fileref1[$low..$hi];
map {s/^/ /} @outlist; # assume it's just context
foreach my $block (@{$hunk->{"blocks"}}) {
foreach my $item ($block->remove) {
my $op = $item->{"sign"}; # -
my $offset = $item->{"item_no"} - $low + $num_added;
$outlist[$offset] =~ s/^ /$op/;
$num_removed++;
}
foreach my $item ($block->insert) {
my $op = $item->{"sign"}; # +
my $i = $item->{"item_no"};
my $offset = $i - $hunk->{"start2"} + $num_removed;
splice(@outlist,$offset,0,"$op$$fileref2[$i]");
$num_added++;
}
}
map {s/$/\n/} @outlist; # add \n's
print @outlist;
}
sub output_context_diff {
my ($hunk, $fileref1, $fileref2) = @_;
my @blocklist;
print "***************\n";
# Calculate item number range.
my $range1 = $hunk->context_range(1);
my $range2 = $hunk->context_range(2);
# Print out file 1 part for each block in context diff format if there are
# any blocks that remove items
print "*** $range1 ****\n";
my $low = $hunk->{"start1"};
my $hi = $hunk->{"end1"};
if (@blocklist = grep {$_->remove} @{$hunk->{"blocks"}}) {
my @outlist = @$fileref1[$low..$hi];
map {s/^/ /} @outlist; # assume it's just context
foreach my $block (@blocklist) {
my $op = $block->op; # - or !
foreach my $item ($block->remove) {
$outlist[$item->{"item_no"} - $low] =~ s/^ /$op/;
}
}
map {s/$/\n/} @outlist; # add \n's
print @outlist;
}
print "--- $range2 ----\n";
$low = $hunk->{"start2"};
$hi = $hunk->{"end2"};
if (@blocklist = grep {$_->insert} @{$hunk->{"blocks"}}) {
my @outlist = @$fileref2[$low..$hi];
map {s/^/ /} @outlist; # assume it's just context
foreach my $block (@blocklist) {
my $op = $block->op; # + or !
foreach my $item ($block->insert) {
$outlist[$item->{"item_no"} - $low] =~ s/^ /$op/;
}
}
map {s/$/\n/} @outlist; # add \n's
print @outlist;
}
}
sub store_ed_diff {
# ed diff prints out diffs *backwards*. So save them while we're generating
# them, then print them out at the end
my $hunk = shift;
unshift @Ed_Hunks, $hunk;
}
sub output_ed_diff {
# This sub is used for ed ('diff -e') OR reverse_ed ('diff -f').
# last arg is type of diff
my $diff_type = $_[-1];
my ($hunk, $fileref1, $fileref2) = @_;
my %op_hash = ('+' => 'a', '-' => 'd', '!' => 'c');
# Can't be any context for this kind of diff, so each hunk has one block
my @blocklist = @{$hunk->{"blocks"}};
warn ("Expecting one block in an ed diff hunk!") if scalar @blocklist != 1;
my $block = $blocklist[0];
my $op = $block->op; # +, -, or !
# Calculate item number range.
# old diff range is just like a context diff range, except the ranges
# are on one line with the action between them.
my $range1 = $hunk->context_range(1);
$range1 =~ s/,/ / if $diff_type eq "REVERSE_ED";
my $action = $op_hash{$op} || warn "unknown op $op";
print ($diff_type eq "ED" ? "$range1$action\n" : "$action$range1\n");
if ($block->insert) {
my @outlist = @$fileref2[$hunk->{"start2"}..$hunk->{"end2"}];
map {s/$/\n/} @outlist; # add \n's
print @outlist;
print ".\n"; # end of ed 'c' or 'a' command
}
}
sub context_range {
# Generate a range of item numbers to print. Only print 1 number if the range
# has only one item in it. Otherwise, it's 'start,end'
# Flag is the number of the file (1 or 2)
my ($hunk, $flag) = @_;
my ($start, $end) = ($hunk->{"start$flag"},$hunk->{"end$flag"});
$start++; $end++; # index from 1, not zero
my $range = ($start < $end) ? "$start,$end" : $end;
return $range;
}
sub unified_range {
# Generate a range of item numbers to print for unified diff
# Print number where block starts, followed by number of lines in the block
# (don't print number of lines if it's 1)
my ($hunk, $flag) = @_;
my ($start, $end) = ($hunk->{"start$flag"},$hunk->{"end$flag"});
$start++; $end++; # index from 1, not zero
my $length = $end - $start + 1;
my $first = $length < 2 ? $end : $start; # strange, but correct...
my $range = $length== 1 ? $first : "$first,$length";
return $range;
}
} # end Package Hunk
########
# Package Block. A block is an operation removing, adding, or changing
# a group of items. Basically, this is just a list of changes, where each
# change adds or deletes a single item.
# (Change could be a separate class, but it didn't seem worth it)
{
package Block;
sub new {
# Input is a chunk from &Algorithm::LCS::diff
# Fields in a block:
# length_diff - how much longer file 2 is than file 1 due to this block
# Each change has:
# sign - '+' for insert, '-' for remove
# item_no - number of the item in the file (e.g., line number)
# We don't bother storing the text of the item
#
my ($class,$chunk) = @_;
my @changes = ();
# This just turns each change into a hash.
foreach my $item (@$chunk) {
my ($sign, $item_no, $text) = @$item;
my $hashref = {"sign" => $sign, "item_no" => $item_no};
push @changes, $hashref;
}
my $block = { "changes" => \@changes };
bless $block, $class;
$block->{"length_diff"} = $block->insert - $block->remove;
return $block;
}
# LOW LEVEL FUNCTIONS
sub op {
# what kind of block is this?
my $block = shift;
my $insert = $block->insert;
my $remove = $block->remove;
$remove && $insert and return '!';
$remove and return '-';
$insert and return '+';
warn "unknown block type";
return '^'; # context block
}
# Returns a list of the changes in this block that remove items
# (or the number of removals if called in scalar context)
sub remove { return grep {$_->{"sign"} eq '-'} @{shift->{"changes"}}; }
# Returns a list of the changes in this block that insert items
sub insert { return grep {$_->{"sign"} eq '+'} @{shift->{"changes"}}; }
} # end of package Block