Module: Algorithm::Diff

Defined in:
lib/algorithm/diff.rb

Class Method Summary collapse

Class Method Details

.diff(list_a, list_b, path) ⇒ Object 



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# File 'lib/algorithm/diff.rb', line 104

def self.diff(list_a,list_b,path)
  hunk_list = []
  hunk = []
  (0..path.size-2).each {|i|
    x,y = path[i]
    mx,my = path[i+1]
    if x == mx
      while y < my
        hunk << [ '+', y, list_b[y]]
        y += 1
      end
    elsif y == my
      while (x < mx)
        hunk << [ '-', x, list_a[x]]
        x += 1
      end
    else
      hunk_list << hunk
      hunk = []
    end
  }
  unless hunk.empty?
    hunk_list << hunk
  end
  return hunk_list
end

.ond(list_a, list_b) ⇒ Object 



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# File 'lib/algorithm/diff.rb', line 3

def self.ond(list_a,list_b)
  m = list_a.size
  n = list_b.size
  delta = m - n
  ofs = max = m + n
  v = Array.new(max * 2 + 2, 0)
  snake = Hash.new()
  nn = Array.new(max+1)
  d = 0
  nextbest = 0
  while (d <= max)
    work = Array.new(n+1)
    nn[d] = work
    k = -d
    best = nextbest
    while (k <= d) 
      if ((k + delta).abs > max - best)
        k+=2
        next
      end
      a = v[k - 1 + ofs]
      b = v[k + 1 + ofs]
      y = ( (k == -d) || (k != d) && (a < b)) ? b : a + 1
      x = y - k
      count = 0
      while ( x < m && y < n && list_a[x] == list_b[y])
        x += 1
        y += 1
        count+= 1
      end
      p = work[y]
      if (p == nil)
        work[y] = p = [x]
      else
        work[y] = (p << x)
      end
      if (count > 0) then
        s = snake[idx = x + y * m]
        s = 0 if s == nil
        if (x >= 0 && s < count)
          snake[idx] = count
        end
      end
      v[k + ofs] = y 
      if (x == m && y == n)
        return [d,snake,nn]
      end
      k += 2
      nextbest = ((pos = x+y) > nextbest) ? pos : nextbest
    end
    d += 1
  end
  return nil
end

.sdiff(list_a, list_b, path) ⇒ Object 



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# File 'lib/algorithm/diff.rb', line 131

def self.sdiff(list_a,list_b,path)
  hunk_list = []
  hunk = []
  (0..path.size-2).each {|i|
    x,y = path[i]
    mx,my = path[i+1]
    if x == mx
      while y < my
        hunk << [ '+', nil, list_b[y] ]
        y += 1
      end
    elsif y == my
      while (x < mx)
        hunk << [ '-', list_a[x], nil ]
        x += 1
      end
    else
      hunk_list << hunk
      while (x < mx && y < my)
        hunk_list << ['u', list_a[x], list_b[y]]
        x += 1
        y += 1
      end
      hunk = []
    end
  }
  unless hunk.empty?
    hunk_list << hunk
  end
  
  list = []
  hunk_list.each {|hunk|
    if hunk.first=='u'
      list << hunk
    elsif hunk.size==1
      list << hunk.first
    else
      del_idx = 0
      while del_idx < hunk.size
        break if hunk[del_idx].first=='-'
        del_idx += 1
      end
      ins_idx = 0
      while ins_idx < hunk.size
        break if hunk[ins_idx].first=='+'
        ins_idx += 1
      end
      while del_idx < hunk.size || ins_idx < hunk.size
        del = nil
        ins = nil
        if del_idx < hunk.size
          del = hunk[del_idx][1]
        end
        if ins_idx < hunk.size
          ins = hunk[ins_idx][2]
        end
        if del && ins
          list << ['c',del,ins]
        elsif del
          list << ['-',del,nil]
        elsif ins
          list << ['+',nil,ins]
        end
        del_idx += 1
        ins_idx += 1
      end
    end
  }
  list
end

.solve(a, b, d, snake, nn) ⇒ Object 



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# File 'lib/algorithm/diff.rb', line 58

def self.solve(a,b,d,snake,nn)
  path = []
  m = a.size
  n = b.size
  d = d - 1
  x = m
  y = n
  path << [x,y]
  mx = -1
  my = -1
  p = nil
  s = nil
  while d >= 0
    p = nn[d]
    s = snake[x + y * m]
    s = 0 if s == nil
    px = x - s
    py = y - s
    mx = -1
    my = -1
    if (((q = p[py-1]) != nil) && q.index(px) != nil)
      mx = px
      my = py - 1
      path << [px, py]
    elsif (((q = p[py]) != nil) && q.index(px - 1) != nil)
      mx = px - 1
      my = py
      path << [px, py]
    elsif (((q = p[py]) != nil) && q.index(px) != nil)
      mx = px
      my = py;
    end
    path << [mx, my]
    x = mx
    y = my
    break if (x == 0 && y == 0)
    d -= 1
  end
  path << [0, 0]
  path = path.reverse
  if (path[1] == [0,0])
    path.shift
  end
  path
end

.traverse(list_a, list_b, path, obj) ⇒ Object 



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# File 'lib/algorithm/diff.rb', line 202

def self.traverse(list_a,list_b,path,obj)
  (0..path.size-2).each {|i|
    x,y = path[i]
    mx,my = path[i+1]
    if x == mx
      while y < my
        obj.discard_b(mx, y, list_b[y])
        y += 1
      end
    elsif y == my
      while (x < mx)
        obj.discard_a(x, my, list_a[x])
        x += 1
      end
    else
      while (x < mx && y < my)
        obj.match(x, y, list_b[y])
        x += 1
        y += 1
      end
    end
  }
  return
end