2 This file is part of LilyPond, the GNU music typesetter.
4 Copyright (C) 1997--2010 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"
24 #include "lily-proto.hh"
26 #include "ly-smobs.icc"
29 Duration::compare (Duration const &left, Duration const &right)
31 return Rational::compare (left.get_length (), right.get_length ());
38 factor_ = Rational (1, 1);
41 Duration::Duration (int log, int d)
45 factor_ = Rational (1, 1);
48 Duration::Duration (Rational r, bool scale)
50 factor_ = Rational (1, 1);
59 /* we want to find the integer k for which 2q/p > 2^k >= q/p.
60 It's simple to check that k' = \floor \log q - \floor \log p
61 satisfies the left inequality and is within a factor of 2 of
62 satistying the right one. Therefore either k = k' or k = k'+1 */
66 int k = intlog2 (q) - intlog2 (p);
67 if (shift_left(p, k) < q)
70 assert (shift_left(p, k) >= q && shift_left(p, (k-1)) < q);
72 /* If we were to write out log (p/q) in base 2, then the position of the
73 first non-zero bit (ie. k in our notation) would be the durlog
74 and the number of consecutive 1s after that bit would be the number of
76 p = shift_left(p, k) - q;
84 /* we only go up to 64th notes */
94 factor_ = r / get_length ();
99 Duration::compressed (Rational m) const
107 Duration::get_length () const
109 Rational mom (1 << abs (durlog_));
112 mom = Rational (1) / mom;
114 Rational delta = mom;
115 for (int i = 0; i < dots_; i++)
117 delta /= Rational (2);
121 return mom * factor_;
125 Duration::to_string () const
130 s = "log = " + ::to_string (durlog_);
132 s = ::to_string (1 << durlog_);
134 s += ::to_string ('.', dots_);
135 if (factor_ != Moment (Rational (1, 1)))
136 s += "*" + factor_.to_string ();
140 IMPLEMENT_TYPE_P (Duration, "ly:duration?");
143 Duration::mark_smob (SCM)
148 IMPLEMENT_SIMPLE_SMOBS (Duration);
150 Duration::print_smob (SCM s, SCM port, scm_print_state *)
152 Duration *r = (Duration *) SCM_CELL_WORD_1 (s);
154 scm_puts ("#<Duration ", port);
155 scm_display (ly_string2scm (r->to_string ()), port);
156 scm_puts (" >", port);
162 Duration::equal_p (SCM a, SCM b)
164 Duration *p = (Duration *) SCM_CELL_WORD_1 (a);
165 Duration *q = (Duration *) SCM_CELL_WORD_1 (b);
167 bool eq = p->dots_ == q->dots_
168 && p->durlog_ == q->durlog_
169 && p->factor_ == q->factor_;
171 return eq ? SCM_BOOL_T : SCM_BOOL_F;
175 Duration::duration_log () const
181 Duration::dot_count () const