xref: /freebsd/contrib/gdtoa/hexnan.c (revision 7aa383846770374466b1dcb2cefd71bde9acf463)
1 /****************************************************************
2 
3 The author of this software is David M. Gay.
4 
5 Copyright (C) 2000 by Lucent Technologies
6 All Rights Reserved
7 
8 Permission to use, copy, modify, and distribute this software and
9 its documentation for any purpose and without fee is hereby
10 granted, provided that the above copyright notice appear in all
11 copies and that both that the copyright notice and this
12 permission notice and warranty disclaimer appear in supporting
13 documentation, and that the name of Lucent or any of its entities
14 not be used in advertising or publicity pertaining to
15 distribution of the software without specific, written prior
16 permission.
17 
18 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
19 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
20 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
21 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
22 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
23 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
24 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
25 THIS SOFTWARE.
26 
27 ****************************************************************/
28 
29 /* Please send bug reports to David M. Gay (dmg at acm dot org,
30  * with " at " changed at "@" and " dot " changed to ".").	*/
31 
32 /* $FreeBSD$ */
33 
34 #include <ctype.h>
35 
36 #include "gdtoaimp.h"
37 
38  static void
39 #ifdef KR_headers
40 L_shift(x, x1, i) ULong *x; ULong *x1; int i;
41 #else
42 L_shift(ULong *x, ULong *x1, int i)
43 #endif
44 {
45 	int j;
46 
47 	i = 8 - i;
48 	i <<= 2;
49 	j = ULbits - i;
50 	do {
51 		*x |= x[1] << j;
52 		x[1] >>= i;
53 		} while(++x < x1);
54 	}
55 
56  int
57 #ifdef KR_headers
58 hexnan(sp, fpi, x0)
59 	CONST char **sp; FPI *fpi; ULong *x0;
60 #else
61 hexnan( CONST char **sp, FPI *fpi, ULong *x0)
62 #endif
63 {
64 	ULong c, h, *x, *x1, *xe;
65 	CONST char *s;
66 	int havedig, hd0, i, nbits;
67 
68 	if (!hexdig['0'])
69 		hexdig_init_D2A();
70 	nbits = fpi->nbits;
71 	x = x0 + (nbits >> kshift);
72 	if (nbits & kmask)
73 		x++;
74 	*--x = 0;
75 	x1 = xe = x;
76 	havedig = hd0 = i = 0;
77 	s = *sp;
78 
79 	/* FreeBSD local: Accept (but ignore) the '0x' prefix. */
80 	if (s[1] == '0' && (s[2] == 'x' || s[2] == 'X'))
81 		s += 2;
82 
83 	while(c = *(CONST unsigned char*)++s) {
84 		if (!(h = hexdig[c])) {
85 #if 0
86 			if (c <= ' ') {
87 				if (hd0 < havedig) {
88 					if (x < x1 && i < 8)
89 						L_shift(x, x1, i);
90 					if (x <= x0) {
91 						i = 8;
92 						continue;
93 						}
94 					hd0 = havedig;
95 					*--x = 0;
96 					x1 = x;
97 					i = 0;
98 					}
99 				continue;
100 				}
101 			if (/*(*/ c == ')' && havedig) {
102 				*sp = s + 1;
103 				break;
104 				}
105 #endif
106 			break;
107 			}
108 		havedig++;
109 		if (++i > 8) {
110 			if (x <= x0)
111 				continue;
112 			i = 1;
113 			*--x = 0;
114 			}
115 		*x = (*x << 4) | h & 0xf;
116 		}
117 	if (havedig && x < x1 && i < 8)
118 		L_shift(x, x1, i);
119 	if (x > x0) {
120 		x1 = x0;
121 		do *x1++ = *x++;
122 			while(x <= xe);
123 		do *x1++ = 0;
124 			while(x1 <= xe);
125 		}
126 	else {
127 		/* truncate high-order word if necessary */
128 		if ( (i = nbits & (ULbits-1)) !=0)
129 			*xe &= ((ULong)0xffffffff) >> (ULbits - i);
130 		}
131 	if (havedig) {
132 	for(x1 = xe;; --x1) {
133 		if (*x1 != 0)
134 			break;
135 		if (x1 == x0) {
136 			*x1 = 1;
137 			break;
138 			}
139 		}
140 	}
141 
142 	/*
143 	 * FreeBSD local: Accept all the sequences allowed by C99 and update
144 	 * the tail pointer correctly. Don't accept any invalid sequences.
145 	 */
146 	if (c == '\0')	/* nan() calls this, too; tolerate a missing ')' */
147 		return STRTOG_NaNbits;
148 	if (c != ')') {
149 		while(c = *(CONST unsigned char*)++s) {
150 			if (c == ')')
151 				break;
152 			if (!isalnum(c) && c != '_')
153 				return STRTOG_NaNbits;
154 		}
155 	}
156 	*sp = s + 1;
157 	return STRTOG_NaNbits;
158 	}
159