From b45f2a64f2dba80aea47d596b38068f71402579a Mon Sep 17 00:00:00 2001
From: =?utf8?q?Michael=20K=C3=A4ppler?= <xmichael-k@web.de>
Date: Sat, 28 Feb 2009 10:20:38 +0100
Subject: [PATCH] This fixes an endless loop in duration.cc:67.
The loop occurred when Duration::Duration(Rational r, bool scale) was called
with r.num() >= 2 * r.den(), f.e. the duration of a longa: r.num = 2,
r.den = 1. If k < 0, the left-shifting-operator << returns an undefined value
instead of right-shifting bits. The fix introduces a new function
shift_left() in misc.hh, which behaves different.
---
lily/duration.cc | 6 +++---
lily/include/misc.hh | 7 +++++++
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/lily/duration.cc b/lily/duration.cc
index af924bb4b1..0b80b1ce1f 100644
--- a/lily/duration.cc
+++ b/lily/duration.cc
@@ -53,16 +53,16 @@ Duration::Duration (Rational r, bool scale)
int p = r.num ();
int q = r.den ();
int k = intlog2 (q) - intlog2 (p);
- if ((p << k) < q)
+ if (shift_left(p, k) < q)
k++;
- assert ((p << k) >= q && (p << (k-1)) < q);
+ 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 = (p << k) - q;
+ p = shift_left(p, k) - q;
dots_ = 0;
while ((p *= 2) >= q)
{
diff --git a/lily/include/misc.hh b/lily/include/misc.hh
index e33d836381..12392c0cac 100644
--- a/lily/include/misc.hh
+++ b/lily/include/misc.hh
@@ -28,6 +28,13 @@ sign (int i)
else return 0;
}
+inline int
+shift_left (int value, int shiftamount)
+{
+ if (shiftamount < 0) return (value >> -shiftamount);
+ else return (value << shiftamount);
+}
+
inline Real
linear_interpolate (Real x, Real x1, Real x2, Real y1, Real y2)
{
--
2.39.5