From 5f03def586723979d479b52dea50d433a643af33 Mon Sep 17 00:00:00 2001
From: martinahansen <martinahansen@74ccb610-7750-0410-82ae-013aeee3265d>
Date: Sat, 16 Apr 2011 07:08:08 +0000
Subject: [PATCH] cleaned patternmatcher code

git-svn-id: http://biopieces.googlecode.com/svn/trunk@1329 74ccb610-7750-0410-82ae-013aeee3265d
---
 code_ruby/Maasha/lib/patternmatcher.rb | 61 ++++++++++++++------------
 1 file changed, 33 insertions(+), 28 deletions(-)

diff --git a/code_ruby/Maasha/lib/patternmatcher.rb b/code_ruby/Maasha/lib/patternmatcher.rb
index 478ffba..8dfc66e 100644
--- a/code_ruby/Maasha/lib/patternmatcher.rb
+++ b/code_ruby/Maasha/lib/patternmatcher.rb
@@ -22,28 +22,31 @@
 
 # >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
 
-# IUPAC nucleotide pair ambiguity equivalents
-EQUAL = {
-  :AA => true, :BU => true, :TH => true, :UY => true,
-  :TT => true, :CB => true, :UH => true, :SC => true,
-  :CC => true, :GB => true, :VA => true, :SG => true,
-  :GG => true, :TB => true, :VC => true, :CS => true,
-  :UU => true, :UB => true, :VG => true, :GS => true,
-  :NA => true, :DA => true, :AV => true, :WA => true,
-  :NT => true, :DG => true, :CV => true, :WT => true,
-  :NC => true, :DT => true, :GV => true, :WU => true,
-  :NG => true, :DU => true, :KG => true, :AW => true,
-  :NU => true, :AD => true, :KT => true, :TW => true,
-  :AN => true, :GD => true, :KU => true, :UW => true,
-  :TN => true, :TD => true, :GK => true, :RA => true,
-  :CN => true, :UD => true, :TK => true, :RG => true,
-  :GN => true, :HA => true, :UK => true, :AR => true,
-  :UN => true, :HC => true, :YC => true, :GR => true,
-  :NN => true, :HT => true, :YT => true, :MA => true,
-  :BC => true, :HU => true, :YU => true, :MC => true,
-  :BG => true, :AH => true, :CY => true, :AM => true,
-  :BT => true, :CH => true, :TY => true, :CM => true,
-}
+# IUPAC nucleotide pair ambiguity equivalents are saved in an
+# array of bit fields.
+
+BIT_A = 1 << 0 
+BIT_T = 1 << 1 
+BIT_C = 1 << 2 
+BIT_G = 1 << 3 
+
+EQUAL          = Array.new(256, 0)
+EQUAL['A'.ord] = BIT_A 
+EQUAL['T'.ord] = BIT_T 
+EQUAL['U'.ord] = BIT_T 
+EQUAL['C'.ord] = BIT_C 
+EQUAL['G'.ord] = BIT_G 
+EQUAL['M'.ord] = (BIT_A|BIT_C)
+EQUAL['R'.ord] = (BIT_A|BIT_G)
+EQUAL['W'.ord] = (BIT_A|BIT_T)
+EQUAL['S'.ord] = (BIT_C|BIT_G)
+EQUAL['Y'.ord] = (BIT_C|BIT_T)
+EQUAL['K'.ord] = (BIT_G|BIT_T)
+EQUAL['B'.ord] = (BIT_C|BIT_G|BIT_T)
+EQUAL['D'.ord] = (BIT_A|BIT_G|BIT_T)
+EQUAL['H'.ord] = (BIT_A|BIT_C|BIT_T)
+EQUAL['V'.ord] = (BIT_A|BIT_C|BIT_G)
+EQUAL['N'.ord] = (BIT_A|BIT_C|BIT_G|BIT_T)
 
 # Module containing code to locate nucleotide patterns in sequences allowing for
 # ambiguity codes and a given maximum edit distance.
@@ -91,16 +94,15 @@ module PatternMatcher
   # returned in an Array.
   def scan(pattern, pos = 0, max_edit_distance = 0)
     matches = []
-    offset  = pos
 
-    while match = match(pattern, offset, max_edit_distance)
+    while match = match(pattern, pos, max_edit_distance)
       if block_given?
         yield match
       else
         matches << match
       end
 
-      offset = match.pos + 1
+      pos = match.pos + 1
     end
 
     return matches unless block_given?
@@ -124,7 +126,7 @@ module PatternMatcher
     new_vector = @vector.dup
 
     (0 ... @pattern.length).each do |i|
-      if EQUAL[(@seq[@pos] + @pattern[i]).upcase.to_sym]
+      if match?(@seq[@pos], @pattern[i])
         new_vector[i + 1] = @vector[i].dup
         new_vector[i + 1].matches += 1
       else
@@ -141,8 +143,6 @@ module PatternMatcher
         elsif insertion?(mismatch, insertion, deletion)
           insertion.insertions += 1
           new_vector[i + 1] = insertion
-        else
-          raise "AAAAarrgh"
         end
       end
     end
@@ -150,6 +150,11 @@ module PatternMatcher
     @vector = new_vector
   end
 
+  # Method to determine if a match occurred.
+  def match?(char1, char2)
+    (EQUAL[char1.upcase.ord] & EQUAL[char2.upcase.ord]) != 0
+  end
+
   # Method to determine if a mismatch occured.
   def mismatch?(mismatch, insertion, deletion)
     if mismatch.edit_distance <= insertion.edit_distance and
-- 
2.39.5