diff.rb
280 lines
| 5.5 KiB
| text/x-ruby
|
RubyLexer
/ lib / diff.rb
|
r580 | class Diff | ||
VERSION = 0.3 | ||||
def Diff.lcs(a, b) | ||||
astart = 0 | ||||
bstart = 0 | ||||
afinish = a.length-1 | ||||
bfinish = b.length-1 | ||||
mvector = [] | ||||
# First we prune off any common elements at the beginning | ||||
while (astart <= afinish && bstart <= afinish && a[astart] == b[bstart]) | ||||
mvector[astart] = bstart | ||||
astart += 1 | ||||
bstart += 1 | ||||
end | ||||
# now the end | ||||
while (astart <= afinish && bstart <= bfinish && a[afinish] == b[bfinish]) | ||||
mvector[afinish] = bfinish | ||||
afinish -= 1 | ||||
bfinish -= 1 | ||||
end | ||||
bmatches = b.reverse_hash(bstart..bfinish) | ||||
thresh = [] | ||||
links = [] | ||||
(astart..afinish).each { |aindex| | ||||
aelem = a[aindex] | ||||
next unless bmatches.has_key? aelem | ||||
k = nil | ||||
bmatches[aelem].reverse.each { |bindex| | ||||
if k && (thresh[k] > bindex) && (thresh[k-1] < bindex) | ||||
thresh[k] = bindex | ||||
else | ||||
k = thresh.replacenextlarger(bindex, k) | ||||
end | ||||
links[k] = [ (k==0) ? nil : links[k-1], aindex, bindex ] if k | ||||
} | ||||
} | ||||
if !thresh.empty? | ||||
link = links[thresh.length-1] | ||||
while link | ||||
mvector[link[1]] = link[2] | ||||
link = link[0] | ||||
end | ||||
end | ||||
return mvector | ||||
end | ||||
def makediff(a, b) | ||||
mvector = Diff.lcs(a, b) | ||||
ai = bi = 0 | ||||
while ai < mvector.length | ||||
bline = mvector[ai] | ||||
if bline | ||||
while bi < bline | ||||
discardb(bi, b[bi]) | ||||
bi += 1 | ||||
end | ||||
match(ai, bi) | ||||
bi += 1 | ||||
else | ||||
discarda(ai, a[ai]) | ||||
end | ||||
ai += 1 | ||||
end | ||||
while ai < a.length | ||||
discarda(ai, a[ai]) | ||||
ai += 1 | ||||
end | ||||
while bi < b.length | ||||
discardb(bi, b[bi]) | ||||
bi += 1 | ||||
end | ||||
match(ai, bi) | ||||
1 | ||||
end | ||||
def compactdiffs | ||||
diffs = [] | ||||
@diffs.each { |df| | ||||
i = 0 | ||||
curdiff = [] | ||||
while i < df.length | ||||
whot = df[i][0] | ||||
s = @isstring ? df[i][2].chr : [df[i][2]] | ||||
p = df[i][1] | ||||
last = df[i][1] | ||||
i += 1 | ||||
while df[i] && df[i][0] == whot && df[i][1] == last+1 | ||||
s << df[i][2] | ||||
last = df[i][1] | ||||
i += 1 | ||||
end | ||||
curdiff.push [whot, p, s] | ||||
end | ||||
diffs.push curdiff | ||||
} | ||||
return diffs | ||||
end | ||||
attr_reader :diffs, :difftype | ||||
def initialize(diffs_or_a, b = nil, isstring = nil) | ||||
if b.nil? | ||||
@diffs = diffs_or_a | ||||
@isstring = isstring | ||||
else | ||||
@diffs = [] | ||||
@curdiffs = [] | ||||
makediff(diffs_or_a, b) | ||||
@difftype = diffs_or_a.class | ||||
end | ||||
end | ||||
def match(ai, bi) | ||||
@diffs.push @curdiffs unless @curdiffs.empty? | ||||
@curdiffs = [] | ||||
end | ||||
def discarda(i, elem) | ||||
@curdiffs.push ['-', i, elem] | ||||
end | ||||
def discardb(i, elem) | ||||
@curdiffs.push ['+', i, elem] | ||||
end | ||||
def compact | ||||
return Diff.new(compactdiffs) | ||||
end | ||||
def compact! | ||||
@diffs = compactdiffs | ||||
end | ||||
def inspect | ||||
@diffs.inspect | ||||
end | ||||
end | ||||
module Diffable | ||||
def diff(b) | ||||
Diff.new(self, b) | ||||
end | ||||
# Create a hash that maps elements of the array to arrays of indices | ||||
# where the elements are found. | ||||
def reverse_hash(range = (0...self.length)) | ||||
revmap = {} | ||||
range.each { |i| | ||||
elem = self[i] | ||||
if revmap.has_key? elem | ||||
revmap[elem].push i | ||||
else | ||||
revmap[elem] = [i] | ||||
end | ||||
} | ||||
return revmap | ||||
end | ||||
def replacenextlarger(value, high = nil) | ||||
high ||= self.length | ||||
if self.empty? || value > self[-1] | ||||
push value | ||||
return high | ||||
end | ||||
# binary search for replacement point | ||||
low = 0 | ||||
while low < high | ||||
index = (high+low)/2 | ||||
found = self[index] | ||||
return nil if value == found | ||||
if value > found | ||||
low = index + 1 | ||||
else | ||||
high = index | ||||
end | ||||
end | ||||
self[low] = value | ||||
# $stderr << "replace #{value} : 0/#{low}/#{init_high} (#{steps} steps) (#{init_high-low} off )\n" | ||||
# $stderr.puts self.inspect | ||||
#gets | ||||
#p length - low | ||||
return low | ||||
end | ||||
def patch(diff) | ||||
newary = nil | ||||
if diff.difftype == String | ||||
newary = diff.difftype.new('') | ||||
else | ||||
newary = diff.difftype.new | ||||
end | ||||
ai = 0 | ||||
bi = 0 | ||||
diff.diffs.each { |d| | ||||
d.each { |mod| | ||||
case mod[0] | ||||
when '-' | ||||
while ai < mod[1] | ||||
newary << self[ai] | ||||
ai += 1 | ||||
bi += 1 | ||||
end | ||||
ai += 1 | ||||
when '+' | ||||
while bi < mod[1] | ||||
newary << self[ai] | ||||
ai += 1 | ||||
bi += 1 | ||||
end | ||||
newary << mod[2] | ||||
bi += 1 | ||||
else | ||||
raise "Unknown diff action" | ||||
end | ||||
} | ||||
} | ||||
while ai < self.length | ||||
newary << self[ai] | ||||
ai += 1 | ||||
bi += 1 | ||||
end | ||||
return newary | ||||
end | ||||
end | ||||
class Array | ||||
include Diffable | ||||
end | ||||
class String | ||||
include Diffable | ||||
end | ||||
=begin | ||||
= Diff | ||||
(({diff.rb})) - computes the differences between two arrays or | ||||
strings. Copyright (C) 2001 Lars Christensen | ||||
== Synopsis | ||||
diff = Diff.new(a, b) | ||||
b = a.patch(diff) | ||||
== Class Diff | ||||
=== Class Methods | ||||
--- Diff.new(a, b) | ||||
--- a.diff(b) | ||||
Creates a Diff object which represent the differences between | ||||
((|a|)) and ((|b|)). ((|a|)) and ((|b|)) can be either be arrays | ||||
of any objects, strings, or object of any class that include | ||||
module ((|Diffable|)) | ||||
== Module Diffable | ||||
The module ((|Diffable|)) is intended to be included in any class for | ||||
which differences are to be computed. Diffable is included into String | ||||
and Array when (({diff.rb})) is (({require}))'d. | ||||
Classes including Diffable should implement (({[]})) to get element at | ||||
integer indices, (({<<})) to append elements to the object and | ||||
(({ClassName#new})) should accept 0 arguments to create a new empty | ||||
object. | ||||
=== Instance Methods | ||||
--- Diffable#patch(diff) | ||||
Applies the differences from ((|diff|)) to the object ((|obj|)) | ||||
and return the result. ((|obj|)) is not changed. ((|obj|)) and | ||||
can be either an array or a string, but must match the object | ||||
from which the ((|diff|)) was created. | ||||
=end | ||||