Class: Diff

Inherits:
Object
  • Object
show all
Defined in:
lib/diff.rb,
lib/unixdiff.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(diffs_or_a, b = nil, isstring = nil) ⇒ Diff

Returns a new instance of Diff.



107
108
109
110
111
112
113
114
115
116
117
 
# File 'lib/diff.rb', line 107

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

Instance Attribute Details

#diffs ⇒ Object (readonly)

Returns the value of attribute diffs.



105
106
107
 
# File 'lib/diff.rb', line 105

def diffs
  @diffs
end

#difftype ⇒ Object (readonly)

Returns the value of attribute difftype.



105
106
107
 
# File 'lib/diff.rb', line 105

def difftype
  @difftype
end

Class Method Details

.lcs(a, b) ⇒ Object 



3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
 
# File 'lib/diff.rb', line 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

Instance Method Details

#compact ⇒ Object 



132
133
134
 
# File 'lib/diff.rb', line 132

def compact
  return Diff.new(compactdiffs)
end

#compact! ⇒ Object 



136
137
138
 
# File 'lib/diff.rb', line 136

def compact!
  @diffs = compactdiffs
end

#compactdiffs ⇒ Object 



82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
 
# File 'lib/diff.rb', line 82

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

#discarda(i, elem) ⇒ Object 



124
125
126
 
# File 'lib/diff.rb', line 124

def discarda(i, elem)
  @curdiffs.push ['-', i, elem]
end

#discardb(i, elem) ⇒ Object 



128
129
130
 
# File 'lib/diff.rb', line 128

def discardb(i, elem)
  @curdiffs.push ['+', i, elem]
end

#inspect ⇒ Object 



140
141
142
 
# File 'lib/diff.rb', line 140

def inspect
  @diffs.inspect
end

#makediff(a, b) ⇒ Object 



53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
 
# File 'lib/diff.rb', line 53

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

#match(ai, bi) ⇒ Object 



119
120
121
122
 
# File 'lib/diff.rb', line 119

def match(ai, bi)
  @diffs.push @curdiffs unless @curdiffs.empty?
  @curdiffs = []
end

#to_diff(io = $defout) ⇒ Object 



22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
 
# File 'lib/unixdiff.rb', line 22

def to_diff(io = $defout)
  offset = 0
  @diffs.each { |b|
    first = b[0][1]
    length = b.length
    action = b[0][0]
    addcount = 0
    remcount = 0
    b.each { |l| 
      if l[0] == "+"
        addcount += 1
      elsif l[0] == "-"
        remcount += 1
      end
    }
    if addcount == 0
      puts "#{diffrange(first+1, first+remcount)}d#{first+offset}"
    elsif remcount == 0
      puts "#{first-offset}a#{diffrange(first+1, first+addcount)}"
    else
      puts "#{diffrange(first+1, first+remcount)}c#{diffrange(first+offset+1, first+offset+addcount)}"
    end
    lastdel = (b[0][0] == "-")
    b.each { |l|
      if l[0] == "-"
        offset -= 1
        print "< "
      elsif l[0] == "+"
        offset += 1
 if lastdel
   lastdel = false
          puts "---"
        end
        print "> "
      end
	print l[2]
    }
  }
end