Branch data Line data Source code
1 : : /*-
2 : : * Copyright (c) 2007 David Schultz
3 : : * All rights reserved.
4 : : *
5 : : * Redistribution and use in source and binary forms, with or without
6 : : * modification, are permitted provided that the following conditions
7 : : * are met:
8 : : * 1. Redistributions of source code must retain the above copyright
9 : : * notice, this list of conditions and the following disclaimer.
10 : : * 2. Redistributions in binary form must reproduce the above copyright
11 : : * notice, this list of conditions and the following disclaimer in the
12 : : * documentation and/or other materials provided with the distribution.
13 : : *
14 : : * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 : : * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 : : * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 : : * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
18 : : * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 : : * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 : : * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 : : * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 : : * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 : : * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 : : * SUCH DAMAGE.
25 : : *
26 : : * $FreeBSD: src/lib/msun/src/s_nan.c,v 1.2 2007/12/18 23:46:32 das Exp $
27 : : */
28 : :
29 : : //VBS
30 : : //#include <sys/endian.h>
31 : : #include <ctype.h>
32 : : #include <float.h>
33 : : #include <openlibm_math.h>
34 : : #include <stdint.h>
35 : : #include <string.h> //for memset
36 : :
37 : : #include "math_private.h"
38 : :
39 : : #if !defined(__APPLE__) && !defined(__FreeBSD__) && !defined(__DragonFly__)
40 : 0 : static __inline int digittoint(int c) {
41 [ # # # # ]: 0 : if ('0' <= c && c <= '9')
42 : 0 : return (c - '0');
43 [ # # # # ]: 0 : else if ('A' <= c && c <= 'F')
44 : 0 : return (c - 'A' + 10);
45 [ # # # # ]: 0 : else if ('a' <= c && c <= 'f')
46 : 0 : return (c - 'a' + 10);
47 : 0 : return 0;
48 : : }
49 : : #endif
50 : :
51 : :
52 : : /*
53 : : * Scan a string of hexadecimal digits (the format nan(3) expects) and
54 : : * make a bit array (using the local endianness). We stop when we
55 : : * encounter an invalid character, NUL, etc. If we overflow, we do
56 : : * the same as gcc's __builtin_nan(), namely, discard the high order bits.
57 : : *
58 : : * The format this routine accepts needs to be compatible with what is used
59 : : * in contrib/gdtoa/hexnan.c (for strtod/scanf) and what is used in
60 : : * __builtin_nan(). In fact, we're only 100% compatible for strings we
61 : : * consider valid, so we might be violating the C standard. But it's
62 : : * impossible to use nan(3) portably anyway, so this seems good enough.
63 : : */
64 : : OLM_DLLEXPORT void
65 : 0 : __scan_nan(u_int32_t *words, int num_words, const char *s)
66 : : {
67 : : int si; /* index into s */
68 : : int bitpos; /* index into words (in bits) */
69 : :
70 : 0 : memset(words, 0, num_words * sizeof(u_int32_t));
71 : :
72 : : /* Allow a leading '0x'. (It's expected, but redundant.) */
73 [ # # # # : 0 : if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X'))
# # ]
74 : 0 : s += 2;
75 : :
76 : : /* Scan forwards in the string, looking for the end of the sequence. */
77 [ # # ]: 0 : for (si = 0; isxdigit(s[si]); si++)
78 : : ;
79 : :
80 : : /* Scan backwards, filling in the bits in words[] as we go. */
81 : : #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
82 [ # # ]: 0 : for (bitpos = 0; bitpos < 32 * num_words; bitpos += 4) {
83 : : #else
84 : : for (bitpos = 32 * num_words - 4; bitpos >= 0; bitpos -= 4) {
85 : : #endif
86 [ # # ]: 0 : if (--si < 0)
87 : 0 : break;
88 : 0 : words[bitpos / 32] |= digittoint(s[si]) << (bitpos % 32);
89 : : }
90 : 0 : }
91 : :
92 : : OLM_DLLEXPORT double
93 : 0 : nan(const char *s)
94 : : {
95 : : union {
96 : : double d;
97 : : u_int32_t bits[2];
98 : : } u;
99 : :
100 : 0 : __scan_nan(u.bits, 2, s);
101 : : #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
102 : 0 : u.bits[1] |= 0x7ff80000;
103 : : #else
104 : : u.bits[0] |= 0x7ff80000;
105 : : #endif
106 : 0 : return (u.d);
107 : : }
108 : :
109 : : OLM_DLLEXPORT float
110 : 0 : nanf(const char *s)
111 : : {
112 : : union {
113 : : float f;
114 : : u_int32_t bits[1];
115 : : } u;
116 : :
117 : 0 : __scan_nan(u.bits, 1, s);
118 : 0 : u.bits[0] |= 0x7fc00000;
119 : 0 : return (u.f);
120 : : }
121 : :
122 : : #if (LDBL_MANT_DIG == 53)
123 : : openlibm_weak_reference(nan, nanl);
124 : : #endif
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