Re: [PATCH] Completion_heads_engraver broken?

[Michael Käppler]

Joe Neeman wrote:
> On Thu, 2009-02-26 at 13:24 +0100, Michael Käppler wrote:
>   
> > Both fixed. Other comments?
> >     
>
> Just one: can you set the environment variables GIT_AUTHOR_NAME and
> GIT_AUTHOR_EMAIL so that an actual name and email show up in the patch?
>   
Done.

>From fda64abf3730cbe811e292a17d58b23e4fd75f0c Mon Sep 17 00:00:00 2001
From: =?utf-8?q?Michael=20K=C3=A4ppler?= <address@hidden>
Date: Sat, 28 Feb 2009 10:20:38 +0100
Subject: [PATCH] This fixes an endless loop in duration.cc:67 when 
Duration::Duration(Rational r, bool scale) is 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 af924bb..0b80b1c 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 e33d836..12392c0 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)
 {
-- 
1.5.6