X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/22a86e9300bc489906b09bad0e6be79588c4b41c..ba5e8b528ff29715f5a9008137e117a9fbcc24b0:/buildtools/Cmake/Scripts/Diff.pm diff --git a/buildtools/Cmake/Scripts/Diff.pm b/buildtools/Cmake/Scripts/Diff.pm deleted file mode 100644 index 5069c220dc..0000000000 --- a/buildtools/Cmake/Scripts/Diff.pm +++ /dev/null @@ -1,1713 +0,0 @@ -package Diff; -# Skip to first "=head" line for documentation. -use strict; - -use integer; # see below in _replaceNextLargerWith() for mod to make - # if you don't use this -use vars qw( $VERSION @EXPORT_OK ); -$VERSION = 1.19_02; -# ^ ^^ ^^-- Incremented at will -# | \+----- Incremented for non-trivial changes to features -# \-------- Incremented for fundamental changes -require Exporter; -*import = \&Exporter::import; -@EXPORT_OK = qw( - prepare LCS LCSidx LCS_length - diff sdiff compact_diff - traverse_sequences traverse_balanced -); - -# McIlroy-Hunt diff algorithm -# Adapted from the Smalltalk code of Mario I. Wolczko, -# by Ned Konz, perl@bike-nomad.com -# Updates by Tye McQueen, http://perlmonks.org/?node=tye - -# Create a hash that maps each element of $aCollection to the set of -# positions it occupies in $aCollection, restricted to the elements -# within the range of indexes specified by $start and $end. -# The fourth parameter is a subroutine reference that will be called to -# generate a string to use as a key. -# Additional parameters, if any, will be passed to this subroutine. -# -# my $hashRef = _withPositionsOfInInterval( \@array, $start, $end, $keyGen ); - -sub _withPositionsOfInInterval -{ - my $aCollection = shift; # array ref - my $start = shift; - my $end = shift; - my $keyGen = shift; - my %d; - my $index; - for ( $index = $start ; $index <= $end ; $index++ ) - { - my $element = $aCollection->[$index]; - my $key = &$keyGen( $element, @_ ); - if ( exists( $d{$key} ) ) - { - unshift ( @{ $d{$key} }, $index ); - } - else - { - $d{$key} = [$index]; - } - } - return wantarray ? %d : \%d; -} - -# Find the place at which aValue would normally be inserted into the -# array. If that place is already occupied by aValue, do nothing, and -# return undef. If the place does not exist (i.e., it is off the end of -# the array), add it to the end, otherwise replace the element at that -# point with aValue. It is assumed that the array's values are numeric. -# This is where the bulk (75%) of the time is spent in this module, so -# try to make it fast! - -sub _replaceNextLargerWith -{ - my ( $array, $aValue, $high ) = @_; - $high ||= $#$array; - - # off the end? - if ( $high == -1 || $aValue > $array->[-1] ) - { - push ( @$array, $aValue ); - return $high + 1; - } - - # binary search for insertion point... - my $low = 0; - my $index; - my $found; - while ( $low <= $high ) - { - $index = ( $high + $low ) / 2; - - # $index = int(( $high + $low ) / 2); # without 'use integer' - $found = $array->[$index]; - - if ( $aValue == $found ) - { - return undef; - } - elsif ( $aValue > $found ) - { - $low = $index + 1; - } - else - { - $high = $index - 1; - } - } - - # now insertion point is in $low. - $array->[$low] = $aValue; # overwrite next larger - return $low; -} - -# This method computes the longest common subsequence in $a and $b. - -# Result is array or ref, whose contents is such that -# $a->[ $i ] == $b->[ $result[ $i ] ] -# foreach $i in ( 0 .. $#result ) if $result[ $i ] is defined. - -# An additional argument may be passed; this is a hash or key generating -# function that should return a string that uniquely identifies the given -# element. It should be the case that if the key is the same, the elements -# will compare the same. If this parameter is undef or missing, the key -# will be the element as a string. - -# By default, comparisons will use "eq" and elements will be turned into keys -# using the default stringizing operator '""'. - -# Additional parameters, if any, will be passed to the key generation -# routine. - -sub _longestCommonSubsequence -{ - my $a = shift; # array ref or hash ref - my $b = shift; # array ref or hash ref - my $counting = shift; # scalar - my $keyGen = shift; # code ref - my $compare; # code ref - - if ( ref($a) eq 'HASH' ) - { # prepared hash must be in $b - my $tmp = $b; - $b = $a; - $a = $tmp; - } - - # Check for bogus (non-ref) argument values - if ( !ref($a) || !ref($b) ) - { - my @callerInfo = caller(1); - die 'error: must pass array or hash references to ' . $callerInfo[3]; - } - - # set up code refs - # Note that these are optimized. - if ( !defined($keyGen) ) # optimize for strings - { - $keyGen = sub { $_[0] }; - $compare = sub { my ( $a, $b ) = @_; $a eq $b }; - } - else - { - $compare = sub { - my $a = shift; - my $b = shift; - &$keyGen( $a, @_ ) eq &$keyGen( $b, @_ ); - }; - } - - my ( $aStart, $aFinish, $matchVector ) = ( 0, $#$a, [] ); - my ( $prunedCount, $bMatches ) = ( 0, {} ); - - if ( ref($b) eq 'HASH' ) # was $bMatches prepared for us? - { - $bMatches = $b; - } - else - { - my ( $bStart, $bFinish ) = ( 0, $#$b ); - - # First we prune off any common elements at the beginning - while ( $aStart <= $aFinish - and $bStart <= $bFinish - and &$compare( $a->[$aStart], $b->[$bStart], @_ ) ) - { - $matchVector->[ $aStart++ ] = $bStart++; - $prunedCount++; - } - - # now the end - while ( $aStart <= $aFinish - and $bStart <= $bFinish - and &$compare( $a->[$aFinish], $b->[$bFinish], @_ ) ) - { - $matchVector->[ $aFinish-- ] = $bFinish--; - $prunedCount++; - } - - # Now compute the equivalence classes of positions of elements - $bMatches = - _withPositionsOfInInterval( $b, $bStart, $bFinish, $keyGen, @_ ); - } - my $thresh = []; - my $links = []; - - my ( $i, $ai, $j, $k ); - for ( $i = $aStart ; $i <= $aFinish ; $i++ ) - { - $ai = &$keyGen( $a->[$i], @_ ); - if ( exists( $bMatches->{$ai} ) ) - { - $k = 0; - for $j ( @{ $bMatches->{$ai} } ) - { - - # optimization: most of the time this will be true - if ( $k and $thresh->[$k] > $j and $thresh->[ $k - 1 ] < $j ) - { - $thresh->[$k] = $j; - } - else - { - $k = _replaceNextLargerWith( $thresh, $j, $k ); - } - - # oddly, it's faster to always test this (CPU cache?). - if ( defined($k) ) - { - $links->[$k] = - [ ( $k ? $links->[ $k - 1 ] : undef ), $i, $j ]; - } - } - } - } - - if (@$thresh) - { - return $prunedCount + @$thresh if $counting; - for ( my $link = $links->[$#$thresh] ; $link ; $link = $link->[0] ) - { - $matchVector->[ $link->[1] ] = $link->[2]; - } - } - elsif ($counting) - { - return $prunedCount; - } - - return wantarray ? @$matchVector : $matchVector; -} - -sub traverse_sequences -{ - my $a = shift; # array ref - my $b = shift; # array ref - my $callbacks = shift || {}; - my $keyGen = shift; - my $matchCallback = $callbacks->{'MATCH'} || sub { }; - my $discardACallback = $callbacks->{'DISCARD_A'} || sub { }; - my $finishedACallback = $callbacks->{'A_FINISHED'}; - my $discardBCallback = $callbacks->{'DISCARD_B'} || sub { }; - my $finishedBCallback = $callbacks->{'B_FINISHED'}; - my $matchVector = _longestCommonSubsequence( $a, $b, 0, $keyGen, @_ ); - - # Process all the lines in @$matchVector - my $lastA = $#$a; - my $lastB = $#$b; - my $bi = 0; - my $ai; - - for ( $ai = 0 ; $ai <= $#$matchVector ; $ai++ ) - { - my $bLine = $matchVector->[$ai]; - if ( defined($bLine) ) # matched - { - &$discardBCallback( $ai, $bi++, @_ ) while $bi < $bLine; - &$matchCallback( $ai, $bi++, @_ ); - } - else - { - &$discardACallback( $ai, $bi, @_ ); - } - } - - # The last entry (if any) processed was a match. - # $ai and $bi point just past the last matching lines in their sequences. - - while ( $ai <= $lastA or $bi <= $lastB ) - { - - # last A? - if ( $ai == $lastA + 1 and $bi <= $lastB ) - { - if ( defined($finishedACallback) ) - { - &$finishedACallback( $lastA, @_ ); - $finishedACallback = undef; - } - else - { - &$discardBCallback( $ai, $bi++, @_ ) while $bi <= $lastB; - } - } - - # last B? - if ( $bi == $lastB + 1 and $ai <= $lastA ) - { - if ( defined($finishedBCallback) ) - { - &$finishedBCallback( $lastB, @_ ); - $finishedBCallback = undef; - } - else - { - &$discardACallback( $ai++, $bi, @_ ) while $ai <= $lastA; - } - } - - &$discardACallback( $ai++, $bi, @_ ) if $ai <= $lastA; - &$discardBCallback( $ai, $bi++, @_ ) if $bi <= $lastB; - } - - return 1; -} - -sub traverse_balanced -{ - my $a = shift; # array ref - my $b = shift; # array ref - my $callbacks = shift || {}; - my $keyGen = shift; - my $matchCallback = $callbacks->{'MATCH'} || sub { }; - my $discardACallback = $callbacks->{'DISCARD_A'} || sub { }; - my $discardBCallback = $callbacks->{'DISCARD_B'} || sub { }; - my $changeCallback = $callbacks->{'CHANGE'}; - my $matchVector = _longestCommonSubsequence( $a, $b, 0, $keyGen, @_ ); - - # Process all the lines in match vector - my $lastA = $#$a; - my $lastB = $#$b; - my $bi = 0; - my $ai = 0; - my $ma = -1; - my $mb; - - while (1) - { - - # Find next match indices $ma and $mb - do { - $ma++; - } while( - $ma <= $#$matchVector - && !defined $matchVector->[$ma] - ); - - last if $ma > $#$matchVector; # end of matchVector? - $mb = $matchVector->[$ma]; - - # Proceed with discard a/b or change events until - # next match - while ( $ai < $ma || $bi < $mb ) - { - - if ( $ai < $ma && $bi < $mb ) - { - - # Change - if ( defined $changeCallback ) - { - &$changeCallback( $ai++, $bi++, @_ ); - } - else - { - &$discardACallback( $ai++, $bi, @_ ); - &$discardBCallback( $ai, $bi++, @_ ); - } - } - elsif ( $ai < $ma ) - { - &$discardACallback( $ai++, $bi, @_ ); - } - else - { - - # $bi < $mb - &$discardBCallback( $ai, $bi++, @_ ); - } - } - - # Match - &$matchCallback( $ai++, $bi++, @_ ); - } - - while ( $ai <= $lastA || $bi <= $lastB ) - { - if ( $ai <= $lastA && $bi <= $lastB ) - { - - # Change - if ( defined $changeCallback ) - { - &$changeCallback( $ai++, $bi++, @_ ); - } - else - { - &$discardACallback( $ai++, $bi, @_ ); - &$discardBCallback( $ai, $bi++, @_ ); - } - } - elsif ( $ai <= $lastA ) - { - &$discardACallback( $ai++, $bi, @_ ); - } - else - { - - # $bi <= $lastB - &$discardBCallback( $ai, $bi++, @_ ); - } - } - - return 1; -} - -sub prepare -{ - my $a = shift; # array ref - my $keyGen = shift; # code ref - - # set up code ref - $keyGen = sub { $_[0] } unless defined($keyGen); - - return scalar _withPositionsOfInInterval( $a, 0, $#$a, $keyGen, @_ ); -} - -sub LCS -{ - my $a = shift; # array ref - my $b = shift; # array ref or hash ref - my $matchVector = _longestCommonSubsequence( $a, $b, 0, @_ ); - my @retval; - my $i; - for ( $i = 0 ; $i <= $#$matchVector ; $i++ ) - { - if ( defined( $matchVector->[$i] ) ) - { - push ( @retval, $a->[$i] ); - } - } - return wantarray ? @retval : \@retval; -} - -sub LCS_length -{ - my $a = shift; # array ref - my $b = shift; # array ref or hash ref - return _longestCommonSubsequence( $a, $b, 1, @_ ); -} - -sub LCSidx -{ - my $a= shift @_; - my $b= shift @_; - my $match= _longestCommonSubsequence( $a, $b, 0, @_ ); - my @am= grep defined $match->[$_], 0..$#$match; - my @bm= @{$match}[@am]; - return \@am, \@bm; -} - -sub compact_diff -{ - my $a= shift @_; - my $b= shift @_; - my( $am, $bm )= LCSidx( $a, $b, @_ ); - my @cdiff; - my( $ai, $bi )= ( 0, 0 ); - push @cdiff, $ai, $bi; - while( 1 ) { - while( @$am && $ai == $am->[0] && $bi == $bm->[0] ) { - shift @$am; - shift @$bm; - ++$ai, ++$bi; - } - push @cdiff, $ai, $bi; - last if ! @$am; - $ai = $am->[0]; - $bi = $bm->[0]; - push @cdiff, $ai, $bi; - } - push @cdiff, 0+@$a, 0+@$b - if $ai < @$a || $bi < @$b; - return wantarray ? @cdiff : \@cdiff; -} - -sub diff -{ - my $a = shift; # array ref - my $b = shift; # array ref - my $retval = []; - my $hunk = []; - my $discard = sub { - push @$hunk, [ '-', $_[0], $a->[ $_[0] ] ]; - }; - my $add = sub { - push @$hunk, [ '+', $_[1], $b->[ $_[1] ] ]; - }; - my $match = sub { - push @$retval, $hunk - if 0 < @$hunk; - $hunk = [] - }; - traverse_sequences( $a, $b, - { MATCH => $match, DISCARD_A => $discard, DISCARD_B => $add }, @_ ); - &$match(); - return wantarray ? @$retval : $retval; -} - -sub sdiff -{ - my $a = shift; # array ref - my $b = shift; # array ref - my $retval = []; - my $discard = sub { push ( @$retval, [ '-', $a->[ $_[0] ], "" ] ) }; - my $add = sub { push ( @$retval, [ '+', "", $b->[ $_[1] ] ] ) }; - my $change = sub { - push ( @$retval, [ 'c', $a->[ $_[0] ], $b->[ $_[1] ] ] ); - }; - my $match = sub { - push ( @$retval, [ 'u', $a->[ $_[0] ], $b->[ $_[1] ] ] ); - }; - traverse_balanced( - $a, - $b, - { - MATCH => $match, - DISCARD_A => $discard, - DISCARD_B => $add, - CHANGE => $change, - }, - @_ - ); - return wantarray ? @$retval : $retval; -} - -######################################## -my $Root= __PACKAGE__; -package Algorithm::Diff::_impl; -use strict; - -sub _Idx() { 0 } # $me->[_Idx]: Ref to array of hunk indices - # 1 # $me->[1]: Ref to first sequence - # 2 # $me->[2]: Ref to second sequence -sub _End() { 3 } # $me->[_End]: Diff between forward and reverse pos -sub _Same() { 4 } # $me->[_Same]: 1 if pos 1 contains unchanged items -sub _Base() { 5 } # $me->[_Base]: Added to range's min and max -sub _Pos() { 6 } # $me->[_Pos]: Which hunk is currently selected -sub _Off() { 7 } # $me->[_Off]: Offset into _Idx for current position -sub _Min() { -2 } # Added to _Off to get min instead of max+1 - -sub Die -{ - require Carp; - Carp::confess( @_ ); -} - -sub _ChkPos -{ - my( $me )= @_; - return if $me->[_Pos]; - my $meth= ( caller(1) )[3]; - Die( "Called $meth on 'reset' object" ); -} - -sub _ChkSeq -{ - my( $me, $seq )= @_; - return $seq + $me->[_Off] - if 1 == $seq || 2 == $seq; - my $meth= ( caller(1) )[3]; - Die( "$meth: Invalid sequence number ($seq); must be 1 or 2" ); -} - -sub getObjPkg -{ - my( $us )= @_; - return ref $us if ref $us; - return $us . "::_obj"; -} - -sub new -{ - my( $us, $seq1, $seq2, $opts ) = @_; - my @args; - for( $opts->{keyGen} ) { - push @args, $_ if $_; - } - for( $opts->{keyGenArgs} ) { - push @args, @$_ if $_; - } - my $cdif= Diff::compact_diff( $seq1, $seq2, @args ); - my $same= 1; - if( 0 == $cdif->[2] && 0 == $cdif->[3] ) { - $same= 0; - splice @$cdif, 0, 2; - } - my @obj= ( $cdif, $seq1, $seq2 ); - $obj[_End] = (1+@$cdif)/2; - $obj[_Same] = $same; - $obj[_Base] = 0; - my $me = bless \@obj, $us->getObjPkg(); - $me->Reset( 0 ); - return $me; -} - -sub Reset -{ - my( $me, $pos )= @_; - $pos= int( $pos || 0 ); - $pos += $me->[_End] - if $pos < 0; - $pos= 0 - if $pos < 0 || $me->[_End] <= $pos; - $me->[_Pos]= $pos || !1; - $me->[_Off]= 2*$pos - 1; - return $me; -} - -sub Base -{ - my( $me, $base )= @_; - my $oldBase= $me->[_Base]; - $me->[_Base]= 0+$base if defined $base; - return $oldBase; -} - -sub Copy -{ - my( $me, $pos, $base )= @_; - my @obj= @$me; - my $you= bless \@obj, ref($me); - $you->Reset( $pos ) if defined $pos; - $you->Base( $base ); - return $you; -} - -sub Next { - my( $me, $steps )= @_; - $steps= 1 if ! defined $steps; - if( $steps ) { - my $pos= $me->[_Pos]; - my $new= $pos + $steps; - $new= 0 if $pos && $new < 0; - $me->Reset( $new ) - } - return $me->[_Pos]; -} - -sub Prev { - my( $me, $steps )= @_; - $steps= 1 if ! defined $steps; - my $pos= $me->Next(-$steps); - $pos -= $me->[_End] if $pos; - return $pos; -} - -sub Diff { - my( $me )= @_; - $me->_ChkPos(); - return 0 if $me->[_Same] == ( 1 & $me->[_Pos] ); - my $ret= 0; - my $off= $me->[_Off]; - for my $seq ( 1, 2 ) { - $ret |= $seq - if $me->[_Idx][ $off + $seq + _Min ] - < $me->[_Idx][ $off + $seq ]; - } - return $ret; -} - -sub Min { - my( $me, $seq, $base )= @_; - $me->_ChkPos(); - my $off= $me->_ChkSeq($seq); - $base= $me->[_Base] if !defined $base; - return $base + $me->[_Idx][ $off + _Min ]; -} - -sub Max { - my( $me, $seq, $base )= @_; - $me->_ChkPos(); - my $off= $me->_ChkSeq($seq); - $base= $me->[_Base] if !defined $base; - return $base + $me->[_Idx][ $off ] -1; -} - -sub Range { - my( $me, $seq, $base )= @_; - $me->_ChkPos(); - my $off = $me->_ChkSeq($seq); - if( !wantarray ) { - return $me->[_Idx][ $off ] - - $me->[_Idx][ $off + _Min ]; - } - $base= $me->[_Base] if !defined $base; - return ( $base + $me->[_Idx][ $off + _Min ] ) - .. ( $base + $me->[_Idx][ $off ] - 1 ); -} - -sub Items { - my( $me, $seq )= @_; - $me->_ChkPos(); - my $off = $me->_ChkSeq($seq); - if( !wantarray ) { - return $me->[_Idx][ $off ] - - $me->[_Idx][ $off + _Min ]; - } - return - @{$me->[$seq]}[ - $me->[_Idx][ $off + _Min ] - .. ( $me->[_Idx][ $off ] - 1 ) - ]; -} - -sub Same { - my( $me )= @_; - $me->_ChkPos(); - return wantarray ? () : 0 - if $me->[_Same] != ( 1 & $me->[_Pos] ); - return $me->Items(1); -} - -my %getName; -BEGIN { - %getName= ( - same => \&Same, - diff => \&Diff, - base => \&Base, - min => \&Min, - max => \&Max, - range=> \&Range, - items=> \&Items, # same thing - ); -} - -sub Get -{ - my $me= shift @_; - $me->_ChkPos(); - my @value; - for my $arg ( @_ ) { - for my $word ( split ' ', $arg ) { - my $meth; - if( $word !~ /^(-?\d+)?([a-zA-Z]+)([12])?$/ - || not $meth= $getName{ lc $2 } - ) { - Die( $Root, ", Get: Invalid request ($word)" ); - } - my( $base, $name, $seq )= ( $1, $2, $3 ); - push @value, scalar( - 4 == length($name) - ? $meth->( $me ) - : $meth->( $me, $seq, $base ) - ); - } - } - if( wantarray ) { - return @value; - } elsif( 1 == @value ) { - return $value[0]; - } - Die( 0+@value, " values requested from ", - $Root, "'s Get in scalar context" ); -} - - -my $Obj= getObjPkg($Root); -no strict 'refs'; - -for my $meth ( qw( new getObjPkg ) ) { - *{$Root."::".$meth} = \&{$meth}; - *{$Obj ."::".$meth} = \&{$meth}; -} -for my $meth ( qw( - Next Prev Reset Copy Base Diff - Same Items Range Min Max Get - _ChkPos _ChkSeq -) ) { - *{$Obj."::".$meth} = \&{$meth}; -} - -1; -__END__ - -=head1 NAME - -Algorithm::Diff - Compute `intelligent' differences between two files / lists - -=head1 SYNOPSIS - - require Algorithm::Diff; - - # This example produces traditional 'diff' output: - - my $diff = Algorithm::Diff->new( \@seq1, \@seq2 ); - - $diff->Base( 1 ); # Return line numbers, not indices - while( $diff->Next() ) { - next if $diff->Same(); - my $sep = ''; - if( ! $diff->Items(2) ) { - printf "%d,%dd%d\n", - $diff->Get(qw( Min1 Max1 Max2 )); - } elsif( ! $diff->Items(1) ) { - printf "%da%d,%d\n", - $diff->Get(qw( Max1 Min2 Max2 )); - } else { - $sep = "---\n"; - printf "%d,%dc%d,%d\n", - $diff->Get(qw( Min1 Max1 Min2 Max2 )); - } - print "< $_" for $diff->Items(1); - print $sep; - print "> $_" for $diff->Items(2); - } - - - # Alternate interfaces: - - use Algorithm::Diff qw( - LCS LCS_length LCSidx - diff sdiff compact_diff - traverse_sequences traverse_balanced ); - - @lcs = LCS( \@seq1, \@seq2 ); - $lcsref = LCS( \@seq1, \@seq2 ); - $count = LCS_length( \@seq1, \@seq2 ); - - ( $seq1idxref, $seq2idxref ) = LCSidx( \@seq1, \@seq2 ); - - - # Complicated interfaces: - - @diffs = diff( \@seq1, \@seq2 ); - - @sdiffs = sdiff( \@seq1, \@seq2 ); - - @cdiffs = compact_diff( \@seq1, \@seq2 ); - - traverse_sequences( - \@seq1, - \@seq2, - { MATCH => \&callback1, - DISCARD_A => \&callback2, - DISCARD_B => \&callback3, - }, - \&key_generator, - @extra_args, - ); - - traverse_balanced( - \@seq1, - \@seq2, - { MATCH => \&callback1, - DISCARD_A => \&callback2, - DISCARD_B => \&callback3, - CHANGE => \&callback4, - }, - \&key_generator, - @extra_args, - ); - - -=head1 INTRODUCTION - -(by Mark-Jason Dominus) - -I once read an article written by the authors of C; they said -that they worked very hard on the algorithm until they found the -right one. - -I think what they ended up using (and I hope someone will correct me, -because I am not very confident about this) was the `longest common -subsequence' method. In the LCS problem, you have two sequences of -items: - - a b c d f g h j q z - - a b c d e f g i j k r x y z - -and you want to find the longest sequence of items that is present in -both original sequences in the same order. That is, you want to find -a new sequence I which can be obtained from the first sequence by -deleting some items, and from the secend sequence by deleting other -items. You also want I to be as long as possible. In this case I -is - - a b c d f g j z - -From there it's only a small step to get diff-like output: - - e h i k q r x y - + - + + - + + + - -This module solves the LCS problem. It also includes a canned function -to generate C-like output. - -It might seem from the example above that the LCS of two sequences is -always pretty obvious, but that's not always the case, especially when -the two sequences have many repeated elements. For example, consider - - a x b y c z p d q - a b c a x b y c z - -A naive approach might start by matching up the C and C that -appear at the beginning of each sequence, like this: - - a x b y c z p d q - a b c a b y c z - -This finds the common subsequence C. But actually, the LCS -is C: - - a x b y c z p d q - a b c a x b y c z - -or - - a x b y c z p d q - a b c a x b y c z - -=head1 USAGE - -(See also the README file and several example -scripts include with this module.) - -This module now provides an object-oriented interface that uses less -memory and is easier to use than most of the previous procedural -interfaces. It also still provides several exportable functions. We'll -deal with these in ascending order of difficulty: C, -C, C, OO interface, C, C, C, -C, and C. - -=head2 C - -Given references to two lists of items, LCS returns an array containing -their longest common subsequence. In scalar context, it returns a -reference to such a list. - - @lcs = LCS( \@seq1, \@seq2 ); - $lcsref = LCS( \@seq1, \@seq2 ); - -C may be passed an optional third parameter; this is a CODE -reference to a key generation function. See L. - - @lcs = LCS( \@seq1, \@seq2, \&keyGen, @args ); - $lcsref = LCS( \@seq1, \@seq2, \&keyGen, @args ); - -Additional parameters, if any, will be passed to the key generation -routine. - -=head2 C - -This is just like C except it only returns the length of the -longest common subsequence. This provides a performance gain of about -9% compared to C. - -=head2 C - -Like C except it returns references to two arrays. The first array -contains the indices into @seq1 where the LCS items are located. The -second array contains the indices into @seq2 where the LCS items are located. - -Therefore, the following three lists will contain the same values: - - my( $idx1, $idx2 ) = LCSidx( \@seq1, \@seq2 ); - my @list1 = @seq1[ @$idx1 ]; - my @list2 = @seq2[ @$idx2 ]; - my @list3 = LCS( \@seq1, \@seq2 ); - -=head2 C - - $diff = Algorithm::Diffs->new( \@seq1, \@seq2 ); - $diff = Algorithm::Diffs->new( \@seq1, \@seq2, \%opts ); - -C computes the smallest set of additions and deletions necessary -to turn the first sequence into the second and compactly records them -in the object. - -You use the object to iterate over I, where each hunk represents -a contiguous section of items which should be added, deleted, replaced, -or left unchanged. - -=over 4 - -The following summary of all of the methods looks a lot like Perl code -but some of the symbols have different meanings: - - [ ] Encloses optional arguments - : Is followed by the default value for an optional argument - | Separates alternate return results - -Method summary: - - $obj = Algorithm::Diff->new( \@seq1, \@seq2, [ \%opts ] ); - $pos = $obj->Next( [ $count : 1 ] ); - $revPos = $obj->Prev( [ $count : 1 ] ); - $obj = $obj->Reset( [ $pos : 0 ] ); - $copy = $obj->Copy( [ $pos, [ $newBase ] ] ); - $oldBase = $obj->Base( [ $newBase ] ); - -Note that all of the following methods C if used on an object that -is "reset" (not currently pointing at any hunk). - - $bits = $obj->Diff( ); - @items|$cnt = $obj->Same( ); - @items|$cnt = $obj->Items( $seqNum ); - @idxs |$cnt = $obj->Range( $seqNum, [ $base ] ); - $minIdx = $obj->Min( $seqNum, [ $base ] ); - $maxIdx = $obj->Max( $seqNum, [ $base ] ); - @values = $obj->Get( @names ); - -Passing in C for an optional argument is always treated the same -as if no argument were passed in. - -=item C - - $pos = $diff->Next(); # Move forward 1 hunk - $pos = $diff->Next( 2 ); # Move forward 2 hunks - $pos = $diff->Next(-5); # Move backward 5 hunks - -C moves the object to point at the next hunk. The object starts -out "reset", which means it isn't pointing at any hunk. If the object -is reset, then C moves to the first hunk. - -C returns a true value iff the move didn't go past the last hunk. -So C will return true iff the object is not reset. - -Actually, C returns the object's new position, which is a number -between 1 and the number of hunks (inclusive), or returns a false value. - -=item C - -C is almost identical to C; it moves to the $Nth -previous hunk. On a 'reset' object, C [and C] move -to the last hunk. - -The position returned by C is relative to the I of the -hunks; -1 for the last hunk, -2 for the second-to-last, etc. - -=item C - - $diff->Reset(); # Reset the object's position - $diff->Reset($pos); # Move to the specified hunk - $diff->Reset(1); # Move to the first hunk - $diff->Reset(-1); # Move to the last hunk - -C returns the object, so, for example, you could use -C<< $diff->Reset()->Next(-1) >> to get the number of hunks. - -=item C - - $copy = $diff->Copy( $newPos, $newBase ); - -C returns a copy of the object. The copy and the orignal object -share most of their data, so making copies takes very little memory. -The copy maintains its own position (separate from the original), which -is the main purpose of copies. It also maintains its own base. - -By default, the copy's position starts out the same as the original -object's position. But C takes an optional first argument to set the -new position, so the following three snippets are equivalent: - - $copy = $diff->Copy($pos); - - $copy = $diff->Copy(); - $copy->Reset($pos); - - $copy = $diff->Copy()->Reset($pos); - -C takes an optional second argument to set the base for -the copy. If you wish to change the base of the copy but leave -the position the same as in the original, here are two -equivalent ways: - - $copy = $diff->Copy(); - $copy->Base( 0 ); - - $copy = $diff->Copy(undef,0); - -Here are two equivalent way to get a "reset" copy: - - $copy = $diff->Copy(0); - - $copy = $diff->Copy()->Reset(); - -=item C - - $bits = $obj->Diff(); - -C returns a true value iff the current hunk contains items that are -different between the two sequences. It actually returns one of the -follow 4 values: - -=over 4 - -=item 3 - -C<3==(1|2)>. This hunk contains items from @seq1 and the items -from @seq2 that should replace them. Both sequence 1 and 2 -contain changed items so both the 1 and 2 bits are set. - -=item 2 - -This hunk only contains items from @seq2 that should be inserted (not -items from @seq1). Only sequence 2 contains changed items so only the 2 -bit is set. - -=item 1 - -This hunk only contains items from @seq1 that should be deleted (not -items from @seq2). Only sequence 1 contains changed items so only the 1 -bit is set. - -=item 0 - -This means that the items in this hunk are the same in both sequences. -Neither sequence 1 nor 2 contain changed items so neither the 1 nor the -2 bits are set. - -=back - -=item C - -C returns a true value iff the current hunk contains items that -are the same in both sequences. It actually returns the list of items -if they are the same or an emty list if they aren't. In a scalar -context, it returns the size of the list. - -=item C - - $count = $diff->Items(2); - @items = $diff->Items($seqNum); - -C returns the (number of) items from the specified sequence that -are part of the current hunk. - -If the current hunk contains only insertions, then -C<< $diff->Items(1) >> will return an empty list (0 in a scalar conext). -If the current hunk contains only deletions, then C<< $diff->Items(2) >> -will return an empty list (0 in a scalar conext). - -If the hunk contains replacements, then both C<< $diff->Items(1) >> and -C<< $diff->Items(2) >> will return different, non-empty lists. - -Otherwise, the hunk contains identical items and all of the following -will return the same lists: - - @items = $diff->Items(1); - @items = $diff->Items(2); - @items = $diff->Same(); - -=item C - - $count = $diff->Range( $seqNum ); - @indices = $diff->Range( $seqNum ); - @indices = $diff->Range( $seqNum, $base ); - -C is like C except that it returns a list of I to -the items rather than the items themselves. By default, the index of -the first item (in each sequence) is 0 but this can be changed by -calling the C method. So, by default, the following two snippets -return the same lists: - - @list = $diff->Items(2); - @list = @seq2[ $diff->Range(2) ]; - -You can also specify the base to use as the second argument. So the -following two snippets I return the same lists: - - @list = $diff->Items(1); - @list = @seq1[ $diff->Range(1,0) ]; - -=item C - - $curBase = $diff->Base(); - $oldBase = $diff->Base($newBase); - -C sets and/or returns the current base (usually 0 or 1) that is -used when you request range information. The base defaults to 0 so -that range information is returned as array indices. You can set the -base to 1 if you want to report traditional line numbers instead. - -=item C - - $min1 = $diff->Min(1); - $min = $diff->Min( $seqNum, $base ); - -C returns the first value that C would return (given the -same arguments) or returns C if C would return an empty -list. - -=item C - -C returns the last value that C would return or C. - -=item C - - ( $n, $x, $r ) = $diff->Get(qw( min1 max1 range1 )); - @values = $diff->Get(qw( 0min2 1max2 range2 same base )); - -C returns one or more scalar values. You pass in a list of the -names of the values you want returned. Each name must match one of the -following regexes: - - /^(-?\d+)?(min|max)[12]$/i - /^(range[12]|same|diff|base)$/i - -The 1 or 2 after a name says which sequence you want the information -for (and where allowed, it is required). The optional number before -"min" or "max" is the base to use. So the following equalities hold: - - $diff->Get('min1') == $diff->Min(1) - $diff->Get('0min2') == $diff->Min(2,0) - -Using C in a scalar context when you've passed in more than one -name is a fatal error (C is called). - -=back - -=head2 C - -Given a reference to a list of items, C returns a reference -to a hash which can be used when comparing this sequence to other -sequences with C or C. - - $prep = prepare( \@seq1 ); - for $i ( 0 .. 10_000 ) - { - @lcs = LCS( $prep, $seq[$i] ); - # do something useful with @lcs - } - -C may be passed an optional third parameter; this is a CODE -reference to a key generation function. See L. - - $prep = prepare( \@seq1, \&keyGen ); - for $i ( 0 .. 10_000 ) - { - @lcs = LCS( $seq[$i], $prep, \&keyGen ); - # do something useful with @lcs - } - -Using C provides a performance gain of about 50% when calling LCS -many times compared with not preparing. - -=head2 C - - @diffs = diff( \@seq1, \@seq2 ); - $diffs_ref = diff( \@seq1, \@seq2 ); - -C computes the smallest set of additions and deletions necessary -to turn the first sequence into the second, and returns a description -of these changes. The description is a list of I; each hunk -represents a contiguous section of items which should be added, -deleted, or replaced. (Hunks containing unchanged items are not -included.) - -The return value of C is a list of hunks, or, in scalar context, a -reference to such a list. If there are no differences, the list will be -empty. - -Here is an example. Calling C for the following two sequences: - - a b c e h j l m n p - b c d e f j k l m r s t - -would produce the following list: - - ( - [ [ '-', 0, 'a' ] ], - - [ [ '+', 2, 'd' ] ], - - [ [ '-', 4, 'h' ], - [ '+', 4, 'f' ] ], - - [ [ '+', 6, 'k' ] ], - - [ [ '-', 8, 'n' ], - [ '-', 9, 'p' ], - [ '+', 9, 'r' ], - [ '+', 10, 's' ], - [ '+', 11, 't' ] ], - ) - -There are five hunks here. The first hunk says that the C at -position 0 of the first sequence should be deleted (C<->). The second -hunk says that the C at position 2 of the second sequence should -be inserted (C<+>). The third hunk says that the C at position 4 -of the first sequence should be removed and replaced with the C -from position 4 of the second sequence. And so on. - -C may be passed an optional third parameter; this is a CODE -reference to a key generation function. See L. - -Additional parameters, if any, will be passed to the key generation -routine. - -=head2 C - - @sdiffs = sdiff( \@seq1, \@seq2 ); - $sdiffs_ref = sdiff( \@seq1, \@seq2 ); - -C computes all necessary components to show two sequences -and their minimized differences side by side, just like the -Unix-utility I does: - - same same - before | after - old < - - - > new - -It returns a list of array refs, each pointing to an array of -display instructions. In scalar context it returns a reference -to such a list. If there are no differences, the list will have one -entry per item, each indicating that the item was unchanged. - -Display instructions consist of three elements: A modifier indicator -(C<+>: Element added, C<->: Element removed, C: Element unmodified, -C: Element changed) and the value of the old and new elements, to -be displayed side-by-side. - -An C of the following two sequences: - - a b c e h j l m n p - b c d e f j k l m r s t - -results in - - ( [ '-', 'a', '' ], - [ 'u', 'b', 'b' ], - [ 'u', 'c', 'c' ], - [ '+', '', 'd' ], - [ 'u', 'e', 'e' ], - [ 'c', 'h', 'f' ], - [ 'u', 'j', 'j' ], - [ '+', '', 'k' ], - [ 'u', 'l', 'l' ], - [ 'u', 'm', 'm' ], - [ 'c', 'n', 'r' ], - [ 'c', 'p', 's' ], - [ '+', '', 't' ], - ) - -C may be passed an optional third parameter; this is a CODE -reference to a key generation function. See L. - -Additional parameters, if any, will be passed to the key generation -routine. - -=head2 C - -C is much like C except it returns a much more -compact description consisting of just one flat list of indices. An -example helps explain the format: - - my @a = qw( a b c e h j l m n p ); - my @b = qw( b c d e f j k l m r s t ); - @cdiff = compact_diff( \@a, \@b ); - # Returns: - # @a @b @a @b - # start start values values - ( 0, 0, # = - 0, 0, # a ! - 1, 0, # b c = b c - 3, 2, # ! d - 3, 3, # e = e - 4, 4, # f ! h - 5, 5, # j = j - 6, 6, # ! k - 6, 7, # l m = l m - 8, 9, # n p ! r s t - 10, 12, # - ); - -The 0th, 2nd, 4th, etc. entries are all indices into @seq1 (@a in the -above example) indicating where a hunk begins. The 1st, 3rd, 5th, etc. -entries are all indices into @seq2 (@b in the above example) indicating -where the same hunk begins. - -So each pair of indices (except the last pair) describes where a hunk -begins (in each sequence). Since each hunk must end at the item just -before the item that starts the next hunk, the next pair of indices can -be used to determine where the hunk ends. - -So, the first 4 entries (0..3) describe the first hunk. Entries 0 and 1 -describe where the first hunk begins (and so are always both 0). -Entries 2 and 3 describe where the next hunk begins, so subtracting 1 -from each tells us where the first hunk ends. That is, the first hunk -contains items C<$diff[0]> through C<$diff[2] - 1> of the first sequence -and contains items C<$diff[1]> through C<$diff[3] - 1> of the second -sequence. - -In other words, the first hunk consists of the following two lists of items: - - # 1st pair 2nd pair - # of indices of indices - @list1 = @a[ $cdiff[0] .. $cdiff[2]-1 ]; - @list2 = @b[ $cdiff[1] .. $cdiff[3]-1 ]; - # Hunk start Hunk end - -Note that the hunks will always alternate between those that are part of -the LCS (those that contain unchanged items) and those that contain -changes. This means that all we need to be told is whether the first -hunk is a 'same' or 'diff' hunk and we can determine which of the other -hunks contain 'same' items or 'diff' items. - -By convention, we always make the first hunk contain unchanged items. -So the 1st, 3rd, 5th, etc. hunks (all odd-numbered hunks if you start -counting from 1) all contain unchanged items. And the 2nd, 4th, 6th, -etc. hunks (all even-numbered hunks if you start counting from 1) all -contain changed items. - -Since @a and @b don't begin with the same value, the first hunk in our -example is empty (otherwise we'd violate the above convention). Note -that the first 4 index values in our example are all zero. Plug these -values into our previous code block and we get: - - @hunk1a = @a[ 0 .. 0-1 ]; - @hunk1b = @b[ 0 .. 0-1 ]; - -And C<0..-1> returns the empty list. - -Move down one pair of indices (2..5) and we get the offset ranges for -the second hunk, which contains changed items. - -Since C<@diff[2..5]> contains (0,0,1,0) in our example, the second hunk -consists of these two lists of items: - - @hunk2a = @a[ $cdiff[2] .. $cdiff[4]-1 ]; - @hunk2b = @b[ $cdiff[3] .. $cdiff[5]-1 ]; - # or - @hunk2a = @a[ 0 .. 1-1 ]; - @hunk2b = @b[ 0 .. 0-1 ]; - # or - @hunk2a = @a[ 0 .. 0 ]; - @hunk2b = @b[ 0 .. -1 ]; - # or - @hunk2a = ( 'a' ); - @hunk2b = ( ); - -That is, we would delete item 0 ('a') from @a. - -Since C<@diff[4..7]> contains (1,0,3,2) in our example, the third hunk -consists of these two lists of items: - - @hunk3a = @a[ $cdiff[4] .. $cdiff[6]-1 ]; - @hunk3a = @b[ $cdiff[5] .. $cdiff[7]-1 ]; - # or - @hunk3a = @a[ 1 .. 3-1 ]; - @hunk3a = @b[ 0 .. 2-1 ]; - # or - @hunk3a = @a[ 1 .. 2 ]; - @hunk3a = @b[ 0 .. 1 ]; - # or - @hunk3a = qw( b c ); - @hunk3a = qw( b c ); - -Note that this third hunk contains unchanged items as our convention demands. - -You can continue this process until you reach the last two indices, -which will always be the number of items in each sequence. This is -required so that subtracting one from each will give you the indices to -the last items in each sequence. - -=head2 C - -C used to be the most general facility provided by -this module (the new OO interface is more powerful and much easier to -use). - -Imagine that there are two arrows. Arrow A points to an element of -sequence A, and arrow B points to an element of the sequence B. -Initially, the arrows point to the first elements of the respective -sequences. C will advance the arrows through the -sequences one element at a time, calling an appropriate user-specified -callback function before each advance. It willadvance the arrows in -such a way that if there are equal elements C<$A[$i]> and C<$B[$j]> -which are equal and which are part of the LCS, there will be some moment -during the execution of C when arrow A is pointing -to C<$A[$i]> and arrow B is pointing to C<$B[$j]>. When this happens, -C will call the C callback function and then -it will advance both arrows. - -Otherwise, one of the arrows is pointing to an element of its sequence -that is not part of the LCS. C will advance that -arrow and will call the C or the C callback, -depending on which arrow it advanced. If both arrows point to elements -that are not part of the LCS, then C will advance -one of them and call the appropriate callback, but it is not specified -which it will call. - -The arguments to C are the two sequences to -traverse, and a hash which specifies the callback functions, like this: - - traverse_sequences( - \@seq1, \@seq2, - { MATCH => $callback_1, - DISCARD_A => $callback_2, - DISCARD_B => $callback_3, - } - ); - -Callbacks for MATCH, DISCARD_A, and DISCARD_B are invoked with at least -the indices of the two arrows as their arguments. They are not expected -to return any values. If a callback is omitted from the table, it is -not called. - -Callbacks for A_FINISHED and B_FINISHED are invoked with at least the -corresponding index in A or B. - -If arrow A reaches the end of its sequence, before arrow B does, -C will call the C callback when it -advances arrow B, if there is such a function; if not it will call -C instead. Similarly if arrow B finishes first. -C returns when both arrows are at the ends of their -respective sequences. It returns true on success and false on failure. -At present there is no way to fail. - -C may be passed an optional fourth parameter; this -is a CODE reference to a key generation function. See L. - -Additional parameters, if any, will be passed to the key generation function. - -If you want to pass additional parameters to your callbacks, but don't -need a custom key generation function, you can get the default by -passing undef: - - traverse_sequences( - \@seq1, \@seq2, - { MATCH => $callback_1, - DISCARD_A => $callback_2, - DISCARD_B => $callback_3, - }, - undef, # default key-gen - $myArgument1, - $myArgument2, - $myArgument3, - ); - -C does not have a useful return value; you are -expected to plug in the appropriate behavior with the callback -functions. - -=head2 C - -C is an alternative to C. It -uses a different algorithm to iterate through the entries in the -computed LCS. Instead of sticking to one side and showing element changes -as insertions and deletions only, it will jump back and forth between -the two sequences and report I occurring as deletions on one -side followed immediatly by an insertion on the other side. - -In addition to the C, C, and C callbacks -supported by C, C supports -a C callback indicating that one element got C by another: - - traverse_balanced( - \@seq1, \@seq2, - { MATCH => $callback_1, - DISCARD_A => $callback_2, - DISCARD_B => $callback_3, - CHANGE => $callback_4, - } - ); - -If no C callback is specified, C -will map C events to C and C actions, -therefore resulting in a similar behaviour as C -with different order of events. - -C might be a bit slower than C, -noticable only while processing huge amounts of data. - -The C function of this module -is implemented as call to C. - -C does not have a useful return value; you are expected to -plug in the appropriate behavior with the callback functions. - -=head1 KEY GENERATION FUNCTIONS - -Most of the functions accept an optional extra parameter. This is a -CODE reference to a key generating (hashing) function that should return -a string that uniquely identifies a given element. It should be the -case that if two elements are to be considered equal, their keys should -be the same (and the other way around). If no key generation function -is provided, the key will be the element as a string. - -By default, comparisons will use "eq" and elements will be turned into keys -using the default stringizing operator '""'. - -Where this is important is when you're comparing something other than -strings. If it is the case that you have multiple different objects -that should be considered to be equal, you should supply a key -generation function. Otherwise, you have to make sure that your arrays -contain unique references. - -For instance, consider this example: - - package Person; - - sub new - { - my $package = shift; - return bless { name => '', ssn => '', @_ }, $package; - } - - sub clone - { - my $old = shift; - my $new = bless { %$old }, ref($old); - } - - sub hash - { - return shift()->{'ssn'}; - } - - my $person1 = Person->new( name => 'Joe', ssn => '123-45-6789' ); - my $person2 = Person->new( name => 'Mary', ssn => '123-47-0000' ); - my $person3 = Person->new( name => 'Pete', ssn => '999-45-2222' ); - my $person4 = Person->new( name => 'Peggy', ssn => '123-45-9999' ); - my $person5 = Person->new( name => 'Frank', ssn => '000-45-9999' ); - -If you did this: - - my $array1 = [ $person1, $person2, $person4 ]; - my $array2 = [ $person1, $person3, $person4, $person5 ]; - Algorithm::Diff::diff( $array1, $array2 ); - -everything would work out OK (each of the objects would be converted -into a string like "Person=HASH(0x82425b0)" for comparison). - -But if you did this: - - my $array1 = [ $person1, $person2, $person4 ]; - my $array2 = [ $person1, $person3, $person4->clone(), $person5 ]; - Algorithm::Diff::diff( $array1, $array2 ); - -$person4 and $person4->clone() (which have the same name and SSN) -would be seen as different objects. If you wanted them to be considered -equivalent, you would have to pass in a key generation function: - - my $array1 = [ $person1, $person2, $person4 ]; - my $array2 = [ $person1, $person3, $person4->clone(), $person5 ]; - Algorithm::Diff::diff( $array1, $array2, \&Person::hash ); - -This would use the 'ssn' field in each Person as a comparison key, and -so would consider $person4 and $person4->clone() as equal. - -You may also pass additional parameters to the key generation function -if you wish. - -=head1 ERROR CHECKING - -If you pass these routines a non-reference and they expect a reference, -they will die with a message. - -=head1 AUTHOR - -This version released by Tye McQueen (http://perlmonks.org/?node=tye). - -=head1 LICENSE - -Parts Copyright (c) 2000-2004 Ned Konz. All rights reserved. -Parts by Tye McQueen. - -This program is free software; you can redistribute it and/or modify it -under the same terms as Perl. - -=head1 MAILING LIST - -Mark-Jason still maintains a mailing list. To join a low-volume mailing -list for announcements related to diff and Algorithm::Diff, send an -empty mail message to mjd-perl-diff-request@plover.com. - -=head1 CREDITS - -Versions through 0.59 (and much of this documentation) were written by: - -Mark-Jason Dominus, mjd-perl-diff@plover.com - -This version borrows some documentation and routine names from -Mark-Jason's, but Diff.pm's code was completely replaced. - -This code was adapted from the Smalltalk code of Mario Wolczko -, which is available at -ftp://st.cs.uiuc.edu/pub/Smalltalk/MANCHESTER/manchester/4.0/diff.st - -C and C were written by Mike Schilli -. - -The algorithm is that described in -I, -CACM, vol.20, no.5, pp.350-353, May 1977, with a few -minor improvements to improve the speed. - -Much work was done by Ned Konz (perl@bike-nomad.com). - -The OO interface and some other changes are by Tye McQueen. - -=cut