instiki/lib/diff/lcs/block.rb

52 lines
1.3 KiB
Ruby

#! /usr/env/bin ruby
#--
# Copyright 2004 Austin Ziegler <diff-lcs@halostatue.ca>
# adapted from:
# Algorithm::Diff (Perl) by Ned Konz <perl@bike-nomad.com>
# Smalltalk by Mario I. Wolczko <mario@wolczko.com>
# implements McIlroy-Hunt diff algorithm
#
# This program is free software. It may be redistributed and/or modified under
# the terms of the GPL version 2 (or later), the Perl Artistic licence, or the
# Ruby licence.
#
# $Id: block.rb,v 1.3 2004/08/08 20:33:09 austin Exp $
#++
# Contains Diff::LCS::Block for bin/ldiff.
# 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. Used by bin/ldiff.
class Diff::LCS::Block
attr_reader :changes, :insert, :remove
def initialize(chunk)
@changes = []
@insert = []
@remove = []
chunk.each do |item|
@changes << item
@remove << item if item.deleting?
@insert << item if item.adding?
end
end
def diff_size
@insert.size - @remove.size
end
def op
case [@remove.empty?, @insert.empty?]
when [false, false]
'!'
when [false, true]
'-'
when [true, false]
'+'
else # [true, true]
'^'
end
end
end