Class: Diff::SequenceMatcher

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

Instance Method Summary collapse

Constructor Details

#initialize(a = [''], b = [''], isjunk = nil, byline = false) ⇒ SequenceMatcher

Returns a new instance of SequenceMatcher.



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# File 'lib/diff.rb', line 38

def initialize(a=[''], b=[''], isjunk=nil, byline=false)
  a = (!byline and a.kind_of? String) ? a.split(//) : a
  b = (!byline and b.kind_of? String) ? b.split(//) : b
  @isjunk = isjunk || proc {}
  set_seqs a, b
end

Instance Method Details

#find_longest_match(alo, ahi, blo, bhi) ⇒ Object 



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# File 'lib/diff.rb', line 100

def find_longest_match(alo, ahi, blo, bhi)
  besti, bestj, bestsize = alo, blo, 0
  
  j2len = {}
  
  (alo..ahi).step do |i|
    newj2len = {}
    (@b2j[@a[i]] || []).each do |j|
      if j < blo
        next
      end
      if j >= bhi
        break
      end
      
      k = newj2len[j] = (j2len[j - 1] || 0) + 1
      if k > bestsize
        besti, bestj, bestsize = i - k + 1, j - k + 1, k
      end
    end
    j2len = newj2len
  end
  
  while besti > alo and bestj > blo and
      not @isbjunk.call(@b[bestj-1]) and
      @a[besti-1] == @b[bestj-1]
    besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
  end
  
  while besti+bestsize < ahi and bestj+bestsize < bhi and
      not @isbjunk.call(@b[bestj+bestsize]) and
      @a[besti+bestsize] == @b[bestj+bestsize]
    bestsize += 1
  end
  
  while besti > alo and bestj > blo and
      @isbjunk.call(@b[bestj-1]) and
      @a[besti-1] == @b[bestj-1]
    besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
  end
  
  while besti+bestsize < ahi and bestj+bestsize < bhi and
      @isbjunk.call(@b[bestj+bestsize]) and
      @a[besti+bestsize] == @b[bestj+bestsize]
    bestsize += 1
  end
  
  [besti, bestj, bestsize]
end

#get_grouped_opcodes(n = 3) ⇒ Object

XXX: untested



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# File 'lib/diff.rb', line 200

def get_grouped_opcodes(n=3)
  codes = get_opcodes
  if codes[0][0] == :equal
    tag, i1, i2, j1, j2 = codes[0]
    codes[0] = tag, [i1, i2 - n].max, i2, [j1, j2-n].max, j2
  end
  
  if codes[-1][0] == :equal
    tag, i1, i2, j1, j2 = codes[-1]
    codes[-1] = tag, i1, min(i2, i1+n), j1, min(j2, j1+n)
  end
  nn = n + n
  group = []
  codes.each do |tag, i1, i2, j1, j2|
    if tag == :equal and i2-i1 > nn
      group.push [tag, i1, [i2, i1 + n].min, j1, [j2, j1 + n].min]
      yield group
      group = []
      i1, j1 = [i1, i2-n].max, [j1, j2-n].max
      group.push [tag, i1, i2, j1 ,j2]
    end
  end
  if group and group.length != 1 and group[0][0] == :equal
    yield group
  end
end

#get_matching_blocks ⇒ Object 



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# File 'lib/diff.rb', line 150

def get_matching_blocks
  return @matching_blocks unless @matching_blocks.nil? or 
    @matching_blocks.empty?
  
  @matching_blocks = []
  la, lb = @a.length, @b.length
  match_block_helper(0, la, 0, lb, @matching_blocks)
  @matching_blocks.push [la, lb, 0]
end

#get_opcodes ⇒ Object 



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# File 'lib/diff.rb', line 173

def get_opcodes
  unless @opcodes.nil? or @opcodes.empty?
    return @opcodes
  end

  i = j = 0
  @opcodes = answer = []
  get_matching_blocks.each do |ai, bj, size|
    tag = if i < ai and j < bj
            :replace
          elsif i < ai
            :delete
          elsif j < bj 
            :insert
          end

    answer.push [tag, i, ai, j, bj] if tag
    
    i, j = ai + size, bj + size
    
    answer.push [:equal, ai, i, bj, j] unless size.zero?
    
  end
  return answer
end

#quick_ratio ⇒ Object 



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# File 'lib/diff.rb', line 234

def quick_ratio
  if @fullbcount.nil? or @fullbcount.empty?
    @fullbcount = {}
    @b.each do |elt|
      @fullbcount[elt] = (@fullbcount[elt] || 0) + 1
    end
  end
  
  avail = {}
  matches = 0
  @a.each do |elt|
    if avail.has_key? elt
      numb = avail[elt]
    else
      numb = @fullbcount[elt] || 0
    end
    avail[elt] = numb - 1
    if numb > 0
      matches += 1
    end
  end
  Diff.calculate_ratio matches, @a.length + @b.length
end

#ratio ⇒ Object 



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# File 'lib/diff.rb', line 227

def ratio
  matches = get_matching_blocks.reduce(0) do |sum, triple|
    sum + triple[-1]
  end
  Diff.calculate_ratio(matches, @a.length + @b.length)
end

#real_quick_ratio ⇒ Object 



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# File 'lib/diff.rb', line 258

def real_quick_ratio
  la, lb = @a.length, @b.length
  Diff.calculate_ratio([la, lb].min, la + lb)
end

#set_seq_a(a) ⇒ Object 



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# File 'lib/diff.rb', line 50

def set_seq_a(a)
  @a = a
  @matching_blocks = @opcodes = nil
end

#set_seq_b(b) ⇒ Object 



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# File 'lib/diff.rb', line 55

def set_seq_b(b)
  @b = b
  @matching_blocks = @opcodes = nil
  chain_b
end

#set_seqs(a, b) ⇒ Object 



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# File 'lib/diff.rb', line 45

def set_seqs(a, b)
  set_seq_a a
  set_seq_b b
end