prevent CNAME/PTR parsing from reading data past the response end

[musl] / src / math / tanl.c

diff --git a/src/math/tanl.c b/src/math/tanl.c
index 0194eaf..6af0671 100644 (file)
--- a/src/math/tanl.c
+++ b/src/math/tanl.c
@@ -1,35 +1,3 @@
-/* origin: FreeBSD /usr/src/lib/msun/src/s_tanl.c */
-/*-
- * Copyright (c) 2007 Steven G. Kargl
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice unmodified, this list of conditions, and the following
- *    disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-/*
- * Limited testing on pseudorandom numbers drawn within [0:4e8] shows
- * an accuracy of <= 1.5 ULP where 247024 values of x out of 40 million
- * possibles resulted in tan(x) that exceeded 0.5 ULP (ie., 0.6%).
- */
-
 #include "libm.h"
 
 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
@@ -40,43 +8,22 @@ long double tanl(long double x)
 #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
 long double tanl(long double x)
 {
-       union IEEEl2bits z;
-       int e0, s;
+       union ldshape u = {x};
        long double y[2];
-       long double hi, lo;
-
-       z.e = x;
-       s = z.bits.sign;
-       z.bits.sign = 0;
-
-       /* If x = +-0 or x is subnormal, then tan(x) = x. */
-       if (z.bits.exp == 0)
-               return x;
-
-       /* If x = NaN or Inf, then tan(x) = NaN. */
-       if (z.bits.exp == 32767)
-               return (x - x) / (x - x);
-
-       /* Optimize the case where x is already within range. */
-       if (z.e < M_PI_4) {
-               hi = __tanl(z.e, 0, 0);
-               return s ? -hi : hi;
-       }
-
-       e0 = __rem_pio2l(x, y);
-       hi = y[0];
-       lo = y[1];
-
-       switch (e0 & 3) {
-       case 0:
-       case 2:
-               hi = __tanl(hi, lo, 0);
-               break;
-       case 1:
-       case 3:
-               hi = __tanl(hi, lo, 1);
-               break;
+       unsigned n;
+
+       u.i.se &= 0x7fff;
+       if (u.i.se == 0x7fff)
+               return x - x;
+       if (u.f < M_PI_4) {
+               if (u.i.se < 0x3fff - LDBL_MANT_DIG/2) {
+                       /* raise inexact if x!=0 and underflow if subnormal */
+                       FORCE_EVAL(u.i.se == 0 ? x*0x1p-120f : x+0x1p120f);
+                       return x;
+               }
+               return __tanl(x, 0, 0);
        }
-       return hi;
+       n = __rem_pio2l(x, y);
+       return __tanl(y[0], y[1], n&1);
 }
 #endif