2 This file is part of LilyPond, the GNU music typesetter.
4 Copyright (C) 1997--2015 Jan Nieuwenhuizen <janneke@gnu.org>
5 Han-Wen Nienhuys <hanwen@xs4all.nl>
7 LilyPond is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 LilyPond is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
21 #include "duration.hh"
23 ADD_SMOB_INIT (Duration);
26 #include "lily-proto.hh"
30 Duration::compare (Duration const &left, Duration const &right)
32 return Rational::compare (left.get_length (), right.get_length ());
39 factor_ = Rational (1, 1);
42 Duration::Duration (int log, int d)
46 factor_ = Rational (1, 1);
49 Duration::Duration (Rational r, bool scale)
51 factor_ = Rational (1, 1);
60 /* we want to find the integer k for which 2q/p > 2^k >= q/p.
61 It's simple to check that k' = \floor \log q - \floor \log p
62 satisfies the left inequality and is within a factor of 2 of
63 satistying the right one. Therefore either k = k' or k = k'+1 */
65 int p = (int) r.num ();
66 int q = (int) r.den ();
67 int k = intlog2 (q) - intlog2 (p);
68 if (shift_left (p, k) < q)
71 assert (shift_left (p, k) >= q && shift_left (p, (k - 1)) < q);
73 /* If we were to write out log (p/q) in base 2, then the position of the
74 first non-zero bit (ie. k in our notation) would be the durlog
75 and the number of consecutive 1s after that bit would be the number of
77 p = shift_left (p, k) - q;
85 /* we only go up to 64th notes */
95 factor_ = r / get_length ();
100 Duration::compressed (Rational m) const
108 Duration::get_length () const
110 Rational mom (1 << abs (durlog_));
113 mom = Rational (1) / mom;
115 Rational delta = mom;
116 for (int i = 0; i < dots_; i++)
118 delta /= Rational (2);
122 return mom * factor_;
126 Duration::to_string () const
131 s = "log = " + ::to_string (durlog_);
133 s = ::to_string (1 << durlog_);
135 s += ::to_string ('.', dots_);
136 if (factor_ != Moment (Rational (1, 1)))
137 s += "*" + factor_.to_string ();
141 const char Duration::type_p_name_[] = "ly:duration?";
145 Duration::print_smob (SCM port, scm_print_state *)
147 scm_puts ("#<Duration ", port);
148 scm_display (ly_string2scm (to_string ()), port);
149 scm_puts (" >", port);
155 Duration::equal_p (SCM a, SCM b)
157 Duration *p = (Duration *) SCM_CELL_WORD_1 (a);
158 Duration *q = (Duration *) SCM_CELL_WORD_1 (b);
160 bool eq = p->dots_ == q->dots_
161 && p->durlog_ == q->durlog_
162 && p->factor_ == q->factor_;
164 return eq ? SCM_BOOL_T : SCM_BOOL_F;
168 Duration::duration_log () const
174 Duration::dot_count () const