Replaced diff.rb with xhtmldiff.rb, which (unlike its predecessor) produces well-formed redline documents.

lib/diff/lcs/hunk.rb

@@ -0,0 +1,257 @@
+#! /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: hunk.rb,v 1.2 2004/08/08 20:33:09 austin Exp $
+#++
+# Contains Diff::LCS::Hunk for bin/ldiff.
+
+require 'diff/lcs/block'
+
+  # 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.) Used in the diff program (bin/diff).
+class Diff::LCS::Hunk
+    # Create a hunk using references to both the old and new data, as well as
+    # the piece of data
+  def initialize(data_old, data_new, piece, context, file_length_difference)
+      # At first, a hunk will have just one Block in it
+    @blocks = [ Diff::LCS::Block.new(piece) ]
+    @data_old = data_old
+    @data_new = data_new
+
+    before = after = file_length_difference
+    after += @blocks[0].diff_size
+    @file_length_difference = after # The caller must get this manually
+
+      # Save the start & end of each array. If the array doesn't exist
+      # (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.
+    if @blocks[0].remove.empty?
+      a1 = a2 = nil
+    else
+      a1 = @blocks[0].remove[0].position
+      a2 = @blocks[0].remove[-1].position
+    end
+
+    if @blocks[0].insert.empty?
+      b1 = b2 = nil
+    else
+      b1 = @blocks[0].insert[0].position
+      b2 = @blocks[0].insert[-1].position
+    end
+
+    @start_old = a1 || (b1 - before)
+    @start_new = b1 || (a1 + before)
+    @end_old   = a2 || (b2 - after)
+    @end_new   = b2 || (a2 + after)
+
+    self.flag_context = context
+  end
+
+  attr_reader :blocks
+  attr_reader :start_old, :start_new
+  attr_reader :end_old, :end_new
+  attr_reader :file_length_difference
+
+    # Change the "start" and "end" fields to note that context should be added
+    # to this hunk
+  attr_accessor :flag_context
+  def flag_context=(context) #:nodoc:
+    return if context.nil? or context.zero?
+
+    add_start = (context > @start_old) ? @start_old : context
+    @start_old -= add_start
+    @start_new -= add_start
+
+    if (@end_old + context) > @data_old.size
+      add_end = @data_old.size - @end_old
+    else
+      add_end = context
+    end
+    @end_old += add_end
+    @end_new += add_end
+  end
+
+  def unshift(hunk)
+    @start_old = hunk.start_old
+    @start_new = hunk.start_new
+    blocks.unshift(*hunk.blocks)
+  end
+
+    # 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
+  def overlaps?(hunk = nil)
+    return nil if hunk.nil?
+
+    a = (@start_old - hunk.end_old) <= 1
+    b = (@start_new - hunk.end_new) <= 1
+    return (a or b)
+  end
+
+  def diff(format)
+    case format
+    when :old
+      old_diff
+    when :unified
+      unified_diff
+    when :context
+      context_diff
+    when :ed
+      self
+    when :reverse_ed, :ed_finish
+      ed_diff(format)
+    else
+      raise "Unknown diff format #{format}."
+    end
+  end
+
+  def each_old(block)
+    @data_old[@start_old .. @end_old].each { |e| yield e }
+  end
+
+  private
+    # Note that an old diff can't have any context. Therefore, we know that
+    # there's only one block in the hunk.
+  def old_diff
+    warn "Expecting only one block in an old diff hunk!" if @blocks.size > 1
+    op_act = { "+" => 'a', "-" => 'd', "!" => "c" }
+
+    block = @blocks[0]
+
+      # 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.
+    s = "#{context_range(:old)}#{op_act[block.op]}#{context_range(:new)}\n"
+      # If removing anything, just print out all the remove lines in the hunk
+      # which is just all the remove lines in the block.
+    @data_old[@start_old .. @end_old].each { |e| s << "< #{e}\n" } unless block.remove.empty?
+    s << "---\n" if block.op == "!"
+    @data_new[@start_new .. @end_new].each { |e| s << "> #{e}\n" } unless block.insert.empty?
+    s
+  end
+
+  def unified_diff
+      # Calculate item number range.
+    s = "@@ -#{unified_range(:old)} +#{unified_range(:new)} @@\n"
+
+      # Outlist starts containing the hunk of the old file. Removing an item
+      # just means putting a '-' in front of it. Inserting an item requires
+      # getting it from the new file 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 the NEW
+      # file -- don't take removed items into account.
+    lo, hi, num_added, num_removed = @start_old, @end_old, 0, 0
+
+    outlist = @data_old[lo .. hi].collect { |e| e.gsub(/^/, ' ') }
+
+    @blocks.each do |block|
+      block.remove.each do |item|
+        op = item.action.to_s # -
+        offset = item.position - lo + num_added
+        outlist[offset].gsub!(/^ /, op.to_s)
+        num_removed += 1
+      end
+      block.insert.each do |item|
+        op = item.action.to_s # +
+        offset = item.position - @start_new + num_removed
+        outlist[offset, 0] = "#{op}#{@data_new[item.position]}"
+        num_added += 1
+      end
+    end
+
+    s << outlist.join("\n")
+  end
+
+  def context_diff
+    s = "***************\n"
+    s << "*** #{context_range(:old)} ****\n"
+    r = context_range(:new)
+
+      # Print out file 1 part for each block in context diff format if there
+      # are any blocks that remove items
+    lo, hi = @start_old, @end_old
+    removes = @blocks.select { |e| not e.remove.empty? }
+    if removes
+      outlist = @data_old[lo .. hi].collect { |e| e.gsub(/^/, '  ') }
+      removes.each do |block|
+        block.remove.each do |item|
+          outlist[item.position - lo].gsub!(/^ /) { block.op } # - or !
+        end
+      end
+      s << outlist.join("\n")
+    end
+
+    s << "\n--- #{r} ----\n"
+    lo, hi = @start_new, @end_new
+    inserts = @blocks.select { |e| not e.insert.empty? }
+    if inserts
+      outlist = @data_new[lo .. hi].collect { |e| e.gsub(/^/, '  ') }
+      inserts.each do |block|
+        block.insert.each do |item|
+          outlist[item.position - lo].gsub!(/^ /) { block.op } # + or !
+        end
+      end
+      s << outlist.join("\n")
+    end
+    s
+  end
+
+  def ed_diff(format)
+    op_act = { "+" => 'a', "-" => 'd', "!" => "c" }
+    warn "Expecting only one block in an old diff hunk!" if @blocks.size > 1
+
+    if format == :reverse_ed
+      s = "#{op_act[@blocks[0].op]}#{context_range(:old)}\n"
+    else
+      s = "#{context_range(:old).gsub(/,/, ' ')}#{op_act[@blocks[0].op]}\n"
+    end
+
+    unless @blocks[0].insert.empty?
+      @data_new[@start_new .. @end_new].each { |e| s << "#{e}\n" }
+      s << ".\n"
+    end
+    s
+  end
+
+    # 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'
+  def context_range(mode)
+    case mode
+    when :old
+      s, e = (@start_old + 1), (@end_old + 1)
+    when :new
+      s, e = (@start_new + 1), (@end_new + 1)
+    end
+
+    (s < e) ? "#{s},#{e}" : "#{e}"
+  end
+
+    # 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)
+  def unified_range(mode)
+    case mode
+    when :old
+      s, e = (@start_old + 1), (@end_old + 1)
+    when :new
+      s, e = (@start_new + 1), (@end_new + 1)
+    end
+
+    length = e - s + 1
+    first = (length < 2) ? e : s # "strange, but correct"
+    (length == 1) ? "#{first}" : "#{first},#{length}"
+  end
+end