[Python-checkins] bpo-33781: audioop: enhance rounding double as int (GH-7447)
Victor Stinner
webhook-mailer at python.org
Wed Jun 6 09:50:52 EDT 2018
https://github.com/python/cpython/commit/45e4efba7fa2abe61d25e4f8b5bf482e19ff1280
commit: 45e4efba7fa2abe61d25e4f8b5bf482e19ff1280
branch: master
author: Victor Stinner <vstinner at redhat.com>
committer: GitHub <noreply at github.com>
date: 2018-06-06T15:50:50+02:00
summary:
bpo-33781: audioop: enhance rounding double as int (GH-7447)
Move the floor() call into fbound() to call floor() on a double
rather than an int. The change should enhance the rounding.
Document also (int)double rounding mode.
files:
M Modules/audioop.c
diff --git a/Modules/audioop.c b/Modules/audioop.c
index 80c8a2a8e521..f4fdeb23ffa9 100644
--- a/Modules/audioop.c
+++ b/Modules/audioop.c
@@ -20,10 +20,17 @@ static const unsigned int masks[] = {0, 0xFF, 0xFFFF, 0xFFFFFF, 0xFFFFFFFF};
static int
fbound(double val, double minval, double maxval)
{
- if (val > maxval)
+ if (val > maxval) {
val = maxval;
- else if (val < minval + 1)
+ }
+ else if (val < minval + 1.0) {
val = minval;
+ }
+
+ /* Round towards minus infinity (-inf) */
+ val = floor(val);
+
+ /* Cast double to integer: round towards zero */
return (int)val;
}
@@ -924,9 +931,8 @@ audioop_mul_impl(PyObject *module, Py_buffer *fragment, int width,
for (i = 0; i < fragment->len; i += width) {
double val = GETRAWSAMPLE(width, fragment->buf, i);
- val *= factor;
- val = floor(fbound(val, minval, maxval));
- SETRAWSAMPLE(width, ncp, i, (int)val);
+ int ival = fbound(val * factor, minval, maxval);
+ SETRAWSAMPLE(width, ncp, i, ival);
}
return rv;
}
@@ -973,9 +979,9 @@ audioop_tomono_impl(PyObject *module, Py_buffer *fragment, int width,
for (i = 0; i < len; i += width*2) {
double val1 = GETRAWSAMPLE(width, cp, i);
double val2 = GETRAWSAMPLE(width, cp, i + width);
- double val = val1*lfactor + val2*rfactor;
- val = floor(fbound(val, minval, maxval));
- SETRAWSAMPLE(width, ncp, i/2, val);
+ double val = val1 * lfactor + val2 * rfactor;
+ int ival = fbound(val, minval, maxval);
+ SETRAWSAMPLE(width, ncp, i/2, ival);
}
return rv;
}
@@ -1021,8 +1027,8 @@ audioop_tostereo_impl(PyObject *module, Py_buffer *fragment, int width,
for (i = 0; i < fragment->len; i += width) {
double val = GETRAWSAMPLE(width, fragment->buf, i);
- int val1 = (int)floor(fbound(val*lfactor, minval, maxval));
- int val2 = (int)floor(fbound(val*rfactor, minval, maxval));
+ int val1 = fbound(val * lfactor, minval, maxval);
+ int val2 = fbound(val * rfactor, minval, maxval);
SETRAWSAMPLE(width, ncp, i*2, val1);
SETRAWSAMPLE(width, ncp, i*2 + width, val2);
}
@@ -1080,7 +1086,7 @@ audioop_add_impl(PyObject *module, Py_buffer *fragment1,
else {
double fval = (double)val1 + (double)val2;
/* truncate in case of overflow */
- newval = (int)floor(fbound(fval, minval, maxval));
+ newval = fbound(fval, minval, maxval);
}
SETRAWSAMPLE(width, ncp, i, newval);
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