class Asearch

a = Asearch.new('abcde')
a.match('abcde') => true
a.match('abXcde',1) => true

a = Asearch.new('abcde')
initstate = a.initstate
laststate = a.state(initstate,'abcde')
laststate[0] & a.acceptpat => non-zero value

Constants

INITPAT
MAXCHAR
VERSION

Attributes

acceptpat[R]

Public Class Methods

new(pat) click to toggle source

# File lib/asearch.rb, line 38
def initialize(pat)
  @shiftpat = []
  @epsilon = 0
  @acceptpat = 0
  mask = INITPAT
  (0...MAXCHAR).each { |c|
    @shiftpat[c] = 0
  }
  chars = pat.unpack("C*")
  chars.each { |c|
    if c == 0x20 then
      @epsilon |= mask
    else
      @shiftpat[c] |= mask
      @shiftpat[toupper(c)] |= mask
      @shiftpat[tolower(c)] |= mask
      mask >>= 1
    end
  }
  @acceptpat = mask
end

Public Instance Methods

initstate() click to toggle source

# File lib/asearch.rb, line 92
def initstate
  [INITPAT, 0, 0, 0]
end

islower(c) click to toggle source

# File lib/asearch.rb, line 26
def islower(c)
  c >= 0x61 && c <= 0x7a
end

isupper(c) click to toggle source

# File lib/asearch.rb, line 22
def isupper(c)
  c >= 0x41 && c <= 0x5a
end

match(str, ambig=0) click to toggle source

# File lib/asearch.rb, line 96
def match(str, ambig=0)
  s = state(initstate,str)
  s[ambig] & acceptpat != 0
end

state(state=nil,str='') click to toggle source

状態stateからテキストstrを認識したときの状態変化

# File lib/asearch.rb, line 70
def state(state=nil,str='')
  if state.nil? then
    state = initstate
  end
  i0 = state[0]
  i1 = state[1]
  i2 = state[2]
  i3 = state[3]
  chars = str.unpack("C*")
  chars.each { |c|
    mask = @shiftpat[c]
    i3 = (i3 & @epsilon) | ((i3 & mask) >> 1) | (i2 >> 1) | i2
    i2 = (i2 & @epsilon) | ((i2 & mask) >> 1) | (i1 >> 1) | i1
    i1 = (i1 & @epsilon) | ((i1 & mask) >> 1) | (i0 >> 1) | i0
    i0 = (i0 & @epsilon) | ((i0 & mask) >> 1)
    i1 |= (i0 >> 1)
    i2 |= (i1 >> 1)
    i3 |= (i2 >> 1)
  }
  [i0, i1, i2, i3]
end

tolower(c) click to toggle source

# File lib/asearch.rb, line 30
def tolower(c)
  isupper(c) ? c + 0x20 : c
end

toupper(c) click to toggle source

# File lib/asearch.rb, line 34
def toupper(c)
  islower(c) ? c - 0x20 : c
end