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gstutils: Fix violations of strict-aliasing rules in gst_util_uint64_scale()

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This commit is contained in:
Sebastian Dröge 2009-08-11 09:16:38 +02:00
parent 3d359729af
commit 6a84be95be
1 changed files with 15 additions and 11 deletions
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26
gst/gstutils.c
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@ -311,18 +311,22 @@ gst_util_div128_64 (guint64 c1, guint64 c0, guint64 denom, guint64 * remainder)
*/ */
guint64 quotient = 0; guint64 quotient = 0;
GstUInt64 _c1;
_c1.ll = c1;
while (_c1.ll) {
GstUInt64 _a;
while (c1) {
guint64 a;
/* add c1 * (2^64 // d) to quotient, store 2^64 % d in a */ /* add c1 * (2^64 // d) to quotient, store 2^64 % d in a */
quotient += c1 * gst_util_two_to_the_64_over_d (denom, &a); quotient += _c1.ll * gst_util_two_to_the_64_over_d (denom, &_a.ll);
/* store the high and low words of c1 * (2^64 % d) in c1 and a /* store the high and low words of c1 * (2^64 % d) in c1 and a
* respectively */ * respectively */
gst_util_uint64_mul_uint64 ((GstUInt64 *) & c1, (GstUInt64 *) & a, c1, a); gst_util_uint64_mul_uint64 (&_c1, &_a, _c1.ll, _a.ll);
/* add a to c0, with a carry into c1 if the result rolls over */ /* add a to c0, with a carry into c1 if the result rolls over */
if (G_MAXUINT64 - c0 < a) if (G_MAXUINT64 - c0 < _a.ll)
c1++; _c1.ll++;
c0 += a; c0 += _a.ll;
} }
/* c1 is 0. use regular integer arithmetic with c0 to complete result */ /* c1 is 0. use regular integer arithmetic with c0 to complete result */
@ -361,17 +365,17 @@ static guint64
gst_util_uint64_scale_uint64_unchecked (guint64 val, guint64 num, gst_util_uint64_scale_uint64_unchecked (guint64 val, guint64 num,
guint64 denom, guint64 * remainder) guint64 denom, guint64 * remainder)
{ {
guint64 c1, c0; GstUInt64 c1, c0;
/* compute 128-bit numerator product */ /* compute 128-bit numerator product */
gst_util_uint64_mul_uint64 ((GstUInt64 *) & c1, (GstUInt64 *) & c0, val, num); gst_util_uint64_mul_uint64 (&c1, &c0, val, num);
/* high word as big as or bigger than denom --> overflow */ /* high word as big as or bigger than denom --> overflow */
if (G_UNLIKELY (c1 >= denom)) if (G_UNLIKELY (c1.ll >= denom))
return G_MAXUINT64; return G_MAXUINT64;
/* compute quotient, fits in 64 bits */ /* compute quotient, fits in 64 bits */
return gst_util_div128_64 (c1, c0, denom, remainder); return gst_util_div128_64 (c1.ll, c0.ll, denom, remainder);
} }
static inline guint64 static inline guint64