X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fduration.cc;h=0b80b1ce1f33dba7ed7ec97910edfdd33913e5b7;hb=7a6cc2409f4640656fb48c193f0b009be8016ec0;hp=3d7cb6fdd917dbd696b7fc3bfdd0266a2a79fc9b;hpb=545092a25d8ca41dc90b87482474b3719f7130a9;p=lilypond.git

diff --git a/lily/duration.cc b/lily/duration.cc
index 3d7cb6fdd9..0b80b1ce1f 100644
--- a/lily/duration.cc
+++ b/lily/duration.cc
@@ -3,7 +3,7 @@
 
   source file of the LilyPond music typesetter
 
-  (c) 1997--2005 Jan Nieuwenhuizen <janneke@gnu.org>
+  (c) 1997--2009 Jan Nieuwenhuizen <janneke@gnu.org>
   Han-Wen Nienhuys <hanwen@xs4all.nl>
 */
 
@@ -34,6 +34,56 @@ Duration::Duration (int log, int d)
   factor_ = Rational (1, 1);
 }
 
+Duration::Duration (Rational r, bool scale)
+{
+  factor_ = Rational (1, 1);
+
+  if (r.num () == 0.0)
+    {
+      durlog_ = 0;
+      dots_ = 0;
+    }
+  else
+    {
+      /* we want to find the integer k for which 2q/p > 2^k >= q/p.
+	 It's simple to check that k' = \floor \log q - \floor \log p
+	 satisfies the left inequality and is within a factor of 2 of
+	 satistying the right one. Therefore either k = k' or k = k'+1 */
+
+      int p = r.num ();
+      int q = r.den ();
+      int k = intlog2 (q) - intlog2 (p);
+      if (shift_left(p, k) < q)
+	k++;
+
+      assert (shift_left(p, k) >= q && shift_left(p, (k-1)) < q);
+
+      /* If we were to write out log (p/q) in base 2, then the position of the
+	 first non-zero bit (ie. k in our notation) would be the durlog
+	 and the number of consecutive 1s after that bit would be the number of
+	 dots */
+      p = shift_left(p, k) - q;
+      dots_ = 0;
+      while ((p *= 2) >= q)
+	{
+	  p -= q;
+	  dots_++;
+	}
+
+      /* we only go up to 64th notes */
+      if (k > 6)
+	{
+	  durlog_ = 6;
+	  dots_ = 0;
+	}
+      else
+	durlog_ = k;
+
+      if (scale || k > 6)
+	factor_ = r / get_length ();
+    }
+}
+
 Duration
 Duration::compressed (Rational m) const
 {
@@ -60,10 +110,10 @@ Duration::get_length () const
   return mom * factor_;
 }
 
-String
+string
 Duration::to_string () const
 {
-  String s;
+  string s;
 
   if (durlog_ < 0)
     s = "log = " + ::to_string (durlog_);
@@ -91,7 +141,7 @@ Duration::print_smob (SCM s, SCM port, scm_print_state *)
   Duration *r = (Duration *) SCM_CELL_WORD_1 (s);
 
   scm_puts ("#<Duration ", port);
-  scm_display (scm_makfrom0str (r->to_string ().to_str0 ()), port);
+  scm_display (ly_string2scm (r->to_string ()), port);
   scm_puts (" >", port);
 
   return 1;