Module: wine
Branch: master
Commit: cac0fedd339e79e16d8890bbc5e5a4fb0eb7d94f
URL: https://source.winehq.org/git/wine.git/?a=commit;h=cac0fedd339e79e16d8890bb…
Author: Jacek Caban <jacek(a)codeweavers.com>
Date: Thu Dec 5 15:40:48 2019 +0100
jscript: Import to_int32 implementation from WebKit.
Signed-off-by: Jacek Caban <jacek(a)codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard(a)winehq.org>
---
dlls/jscript/jsutils.c | 63 +++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 50 insertions(+), 13 deletions(-)
diff --git a/dlls/jscript/jsutils.c b/dlls/jscript/jsutils.c
index 0702c4e0be..a36c9c1e5b 100644
--- a/dlls/jscript/jsutils.c
+++ b/dlls/jscript/jsutils.c
@@ -657,37 +657,74 @@ HRESULT to_integer(script_ctx_t *ctx, jsval_t v, double *ret)
return S_OK;
}
+static INT32 double_to_int32(double number)
+{
+ INT32 exp, result;
+ union {
+ double d;
+ INT64 n;
+ } bits;
+
+ bits.d = number;
+ exp = ((INT32)(bits.n >> 52) & 0x7ff) - 0x3ff;
+
+ /* If exponent < 0 there will be no bits to the left of the decimal point
+ * after rounding; if the exponent is > 83 then no bits of precision can be
+ * left in the low 32-bit range of the result (IEEE-754 doubles have 52 bits
+ * of fractional precision).
+ * Note this case handles 0, -0, and all infinte, NaN, & denormal value. */
+ if(exp < 0 || exp > 83)
+ return 0;
+
+ /* Select the appropriate 32-bits from the floating point mantissa. If the
+ * exponent is 52 then the bits we need to select are already aligned to the
+ * lowest bits of the 64-bit integer representation of tghe number, no need
+ * to shift. If the exponent is greater than 52 we need to shift the value
+ * left by (exp - 52), if the value is less than 52 we need to shift right
+ * accordingly. */
+ result = (exp > 52) ? bits.n << (exp - 52) : bits.n >> (52 - exp);
+
+ /* IEEE-754 double precision values are stored omitting an implicit 1 before
+ * the decimal point; we need to reinsert this now. We may also the shifted
+ * invalid bits into the result that are not a part of the mantissa (the sign
+ * and exponent bits from the floatingpoint representation); mask these out. */
+ if(exp < 32) {
+ INT32 missing_one = 1 << exp;
+ result &= missing_one - 1;
+ result += missing_one;
+ }
+
+ /* If the input value was negative (we could test either 'number' or 'bits',
+ * but testing 'bits' is likely faster) invert the result appropriately. */
+ return bits.n < 0 ? -result : result;
+}
+
/* ECMA-262 3rd Edition 9.5 */
HRESULT to_int32(script_ctx_t *ctx, jsval_t v, INT *ret)
{
double n;
HRESULT hres;
- const double p32 = (double)0xffffffff + 1;
-
hres = to_number(ctx, v, &n);
if(FAILED(hres))
return hres;
- if(is_finite(n))
- n = n > 0 ? fmod(n, p32) : -fmod(-n, p32);
- else
- n = 0;
-
- *ret = (UINT32)n;
+ *ret = double_to_int32(n);
return S_OK;
}
/* ECMA-262 3rd Edition 9.6 */
HRESULT to_uint32(script_ctx_t *ctx, jsval_t val, UINT32 *ret)
{
- INT32 n;
+ double n;
HRESULT hres;
- hres = to_int32(ctx, val, &n);
- if(SUCCEEDED(hres))
- *ret = n;
- return hres;
+ hres = to_number(ctx, val, &n);
+ if(FAILED(hres))
+ return hres;
+
+ *ret = double_to_int32(n);
+ return S_OK;
}
HRESULT double_to_string(double n, jsstr_t **str)