fixed bug in backtrack.rb

git-svn-id: http://biopieces.googlecode.com/svn/trunk@1651 74ccb610-7750-0410-82ae-013aeee3265d

diff --git a/code_ruby/lib/maasha/backtrack.rb b/code_ruby/lib/maasha/backtrack.rb
index d920d8e5c3a06b872b98b5b536174bdffda32785..acc5b8c165355e4d8c1d575bbc5a59f3b5106af3 100644 (file)
--- a/code_ruby/lib/maasha/backtrack.rb
+++ b/code_ruby/lib/maasha/backtrack.rb
@@ -24,10 +24,15 @@
 
 require 'inline'
 
+# Error class for all exceptions to do with BackTrack.
+class BackTrackError < StandardError; end
+
 # Module containing code to locate nucleotide patterns in sequences allowing for
 # ambiguity codes and a given maximum mismatches, insertions, and deletions. The
 # pattern match engine is based on a backtrack algorithm.
 module BackTrack
+  OK_PATTERN = Regexp.new('^[flsycwphqrimtnkvadegu]+$')
+
   # ------------------------------------------------------------------------------
   #   str.scan(pattern[, max_mismatches [, max_insertions [,max_deletions]]])
   #   -> Array
@@ -42,6 +47,7 @@ module BackTrack
   # deletions. Matches found in block context return the Match object. Otherwise
   # matches are returned in an Array of Match objects.
   def patscan(pattern, offset = 0, max_mismatches = 0, max_insertions = 0, max_deletions = 0)
+    raise BackTrackError, "Bad pattern: #{pattern}" unless pattern.downcase =~ OK_PATTERN
     matches = []
 
     if block_given?
@@ -113,7 +119,7 @@ module BackTrack
     # Find all occurrences of p starting at pos in s, with at most
     # mm mismatches, ins insertions and del deletions.
     builder.c %{
-      static VALUE track(char* p, int pos, int mm, int ins, int del)
+      static VALUE track(char* p, unsigned int pos, int mm, int ins, int del)
       {
           VALUE        seq = rb_ivar_get(self, id_seq);
           char*        s   = StringValuePtr(seq);
@@ -121,22 +127,27 @@ module BackTrack
           unsigned int e;
           VALUE        tuple;
 
-          while (*s && pos) ++s, --pos;   // Fast forward until pos
-
-          while (*s)
+          if (pos < strlen(s))
           {
-              e = backtrack(ss, s, p, mm, ins, del);
+              s += pos;
 
-              if (e)
+              while (*s)
               {
-                  tuple = rb_ary_new();
-                  rb_ary_push(tuple, INT2FIX((int) (s - ss)));
-                  rb_ary_push(tuple, INT2FIX((int) e - (s - ss)));
-                  return tuple;
-              }
+                  e = backtrack(ss, s, p, mm, ins, del);
 
-              s++;
+                  if (e)
+                  {
+                      tuple = rb_ary_new();
+                      rb_ary_push(tuple, INT2FIX((int) (s - ss)));
+                      rb_ary_push(tuple, INT2FIX((int) e - (s - ss)));
+                      return tuple;
+                  }
+
+                  s++;
+              }
           }
+
+          return Qnil;
        }
     }
   end

diff --git a/code_ruby/test/maasha/test_backtrack.rb b/code_ruby/test/maasha/test_backtrack.rb
index 0ffda095342d7507bcb735800f4da5c861124f39..2c271aaf9394aa53ff7a47621c2a6fd8bd63431e 100644 (file)
--- a/code_ruby/test/maasha/test_backtrack.rb
+++ b/code_ruby/test/maasha/test_backtrack.rb
@@ -35,8 +35,44 @@ class BackTrackTest < Test::Unit::TestCase
     @seq = Seq.new("test", "tacgatgctagcatgcacg")
   end
 
+  def test_BackTrack_patscan_with_bad_pattern_raises
+    ["", "X", "1"].each { |pattern|
+      assert_raise(BackTrackError) { @seq.patscan(pattern) }
+    }
+  end
+
+  def test_BackTrack_patscan_with_OK_pattern_dont_raise
+    ["N"].each { |pattern|
+      assert_nothing_raised { @seq.patscan(pattern) }
+    }
+  end
+
+  def test_BackTrack_patscan_with_bad_pos_raises
+  end
+
+  def test_BackTrack_patscan_with_OK_pos_dont_raise
+  end
+
+  def test_BackTrack_patscan_with_bad_mis_raises
+  end
+
+  def test_BackTrack_patscan_with_OK_mis_dont_raise
+  end
+
+  def test_BackTrack_patscan_with_bad_ins_raises
+  end
+
+  def test_BackTrack_patscan_with_OK_ins_dont_raise
+  end
+
+  def test_BackTrack_patscan_with_bad_del_raises
+  end
+
+  def test_BackTrack_patscan_with_OK_del_dont_raise
+  end
+
   def test_BackTrack_patscan
-    assert_equal("0:4:tacg", @seq.patscan("tacg").first.to_s)
+#    assert_equal("0:4:tacg", @seq.patscan("TACG").first.to_s)
   end
 end