[number] Optimize _pow10 constants (#1963)
diff --git a/src/hb-number-parser.hh b/src/hb-number-parser.hh
index 49ade7a..664a6d9 100644
--- a/src/hb-number-parser.hh
+++ b/src/hb-number-parser.hh
@@ -96,28 +96,23 @@
#line 70 "hb-number-parser.rl"
-constexpr double _pow2 (double x) { return x * x; }
-constexpr double _pow10_of_2i (unsigned int n)
-{ return n == 1 ? 10. : _pow2 (_pow10_of_2i (n >> 1)); }
-
-static const double _powers_of_10[] =
-{
- _pow10_of_2i (0x100),
- _pow10_of_2i (0x80),
- _pow10_of_2i (0x40),
- _pow10_of_2i (0x20),
- _pow10_of_2i (0x10),
- _pow10_of_2i (0x8),
- _pow10_of_2i (0x4),
- _pow10_of_2i (0x2),
- _pow10_of_2i (0x1),
-};
-
/* Works only for n < 512 */
inline double
_pow10 (unsigned int exponent)
{
- unsigned int mask = 0x100; /* Should be same with the first element */
+ static const double _powers_of_10[] =
+ {
+ 1.0e+256,
+ 1.0e+128,
+ 1.0e+64,
+ 1.0e+32,
+ 1.0e+16,
+ 1.0e+8,
+ 10000.,
+ 100.,
+ 10.
+ };
+ unsigned int mask = 1 << (ARRAY_LENGTH (_powers_of_10) - 1);
double result = 1;
for (const double *power = _powers_of_10; mask; ++power, mask >>= 1)
if (exponent & mask) result *= *power;
@@ -143,12 +138,12 @@
int cs;
-#line 147 "hb-number-parser.hh"
+#line 142 "hb-number-parser.hh"
{
cs = double_parser_start;
}
-#line 152 "hb-number-parser.hh"
+#line 147 "hb-number-parser.hh"
{
int _slen;
int _trans;
@@ -206,7 +201,7 @@
exp_overflow = true;
}
break;
-#line 210 "hb-number-parser.hh"
+#line 205 "hb-number-parser.hh"
}
_again:
@@ -218,7 +213,7 @@
_out: {}
}
-#line 121 "hb-number-parser.rl"
+#line 116 "hb-number-parser.rl"
*end_ptr = (char *) p;
@@ -229,8 +224,8 @@
if (unlikely (exp_overflow))
{
if (value == 0) return value;
- if (exp_neg) return neg ? -DBL_MIN : DBL_MIN;
- else return neg ? -DBL_MAX : DBL_MAX;
+ if (exp_neg) return neg ? -DBL_MIN : DBL_MIN;
+ else return neg ? -DBL_MAX : DBL_MAX;
}
if (exp)
