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Avoid infinite loop on negative exponent; fix #3677

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matz committed May 31, 2017
1 parent acd3ac6 commit 877f9d02e6df8d21de7a53586155f757caab58d0
Showing with 5 additions and 8 deletions.
  1. +5 −8 src/numeric.c
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@@ -60,26 +60,23 @@ num_pow(mrb_state *mrb, mrb_value x)
mrb_int base = mrb_fixnum(x);
mrb_int exp = mrb_fixnum(y);
mrb_int result = 1;
mrb_bool ok = TRUE;
if (exp < 0) goto float_pow;
for (;;) {
if (exp & 1) {
if (mrb_int_mul_overflow(result, base, &result)) {
ok = FALSE;
break;
goto float_pow;
}
}
exp >>= 1;
if (exp == 0) break;
if (mrb_int_mul_overflow(base, base, &base)) {
ok = FALSE;
break;
goto float_pow;
}
}
if (ok) {
return mrb_fixnum_value(result);
}
return mrb_fixnum_value(result);
}
float_pow:
d = pow(mrb_to_flo(mrb, x), mrb_to_flo(mrb, y));
return mrb_float_value(mrb, d);
}

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