X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fduration.cc;h=880b22c46a3575d1fc37bf78943d45992ca1ba8b;hb=97a0169312a260933246ab224e4f8b0969871dd5;hp=1618489027dd7d74c53c9e4952fb4a6b0fce4be3;hpb=f9214bac21e9926dc3248416f58190c98c4167a9;p=lilypond.git

diff --git a/lily/duration.cc b/lily/duration.cc
index 1618489027..880b22c46a 100644
--- a/lily/duration.cc
+++ b/lily/duration.cc
@@ -1,10 +1,21 @@
 /*
-  duration.cc -- implement Duration
+  This file is part of LilyPond, the GNU music typesetter.
 
-  source file of the LilyPond music typesetter
-
-  (c) 1997--2007 Jan Nieuwenhuizen <janneke@gnu.org>
+  Copyright (C) 1997--2015 Jan Nieuwenhuizen <janneke@gnu.org>
   Han-Wen Nienhuys <hanwen@xs4all.nl>
+
+  LilyPond is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  LilyPond is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "duration.hh"
@@ -12,7 +23,6 @@
 #include "misc.hh"
 #include "lily-proto.hh"
 
-#include "ly-smobs.icc"
 
 int
 Duration::compare (Duration const &left, Duration const &right)
@@ -34,6 +44,56 @@ 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 = (int) r.num ();
+      int q = (int) 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
 {
@@ -76,22 +136,14 @@ Duration::to_string () const
   return s;
 }
 
-IMPLEMENT_TYPE_P (Duration, "ly:duration?");
+const char * const Duration::type_p_name_ = "ly:duration?";
 
-SCM
-Duration::mark_smob (SCM)
-{
-  return SCM_EOL;
-}
 
-IMPLEMENT_SIMPLE_SMOBS (Duration);
 int
-Duration::print_smob (SCM s, SCM port, scm_print_state *)
+Duration::print_smob (SCM port, scm_print_state *) const
 {
-  Duration *r = (Duration *) SCM_CELL_WORD_1 (s);
-
   scm_puts ("#<Duration ", port);
-  scm_display (ly_string2scm (r->to_string ()), port);
+  scm_display (ly_string2scm (to_string ()), port);
   scm_puts (" >", port);
 
   return 1;
@@ -100,12 +152,12 @@ Duration::print_smob (SCM s, SCM port, scm_print_state *)
 SCM
 Duration::equal_p (SCM a, SCM b)
 {
-  Duration *p = (Duration *) SCM_CELL_WORD_1 (a);
-  Duration *q = (Duration *) SCM_CELL_WORD_1 (b);
+  Duration *p = unsmob<Duration> (a);
+  Duration *q = unsmob<Duration> (b);
 
   bool eq = p->dots_ == q->dots_
-    && p->durlog_ == q->durlog_
-    && p->factor_ == q->factor_;
+            && p->durlog_ == q->durlog_
+            && p->factor_ == q->factor_;
 
   return eq ? SCM_BOOL_T : SCM_BOOL_F;
 }