1 /* $NetBSD: gethex.c,v 1.3.14.1 2008/04/08 21:10:55 jdc Exp $ */
2
3 /****************************************************************
4
5 The author of this software is David M. Gay.
6
7 Copyright (C) 1998 by Lucent Technologies
8 All Rights Reserved
9
10 Permission to use, copy, modify, and distribute this software and
11 its documentation for any purpose and without fee is hereby
12 granted, provided that the above copyright notice appear in all
13 copies and that both that the copyright notice and this
14 permission notice and warranty disclaimer appear in supporting
15 documentation, and that the name of Lucent or any of its entities
16 not be used in advertising or publicity pertaining to
17 distribution of the software without specific, written prior
18 permission.
19
20 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
21 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
22 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
23 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
24 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
25 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
26 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
27 THIS SOFTWARE.
28
29 ****************************************************************/
30
31 /* Please send bug reports to David M. Gay (dmg at acm dot org,
32 * with " at " changed at "@" and " dot " changed to "."). */
33 #include <LibConfig.h>
34
35 #include "gdtoaimp.h"
36
37 #ifdef USE_LOCALE
38 #include "locale.h"
39 #endif
40
41 int
gethex(CONST char ** sp,CONST FPI * fpi,Long * expt,Bigint ** bp,int sign)42 gethex( CONST char **sp, CONST FPI *fpi, Long *expt, Bigint **bp, int sign)
43 {
44 Bigint *b;
45 CONST unsigned char *decpt, *s0, *s, *s1;
46 int esign, havedig, irv, k, n, nbits, up, zret;
47 ULong L, lostbits, *x;
48 Long e, e1;
49 #ifdef USE_LOCALE
50 unsigned char decimalpoint = *localeconv()->decimal_point;
51 #else
52 #define decimalpoint '.'
53 #endif
54
55 if (!hexdig['0'])
56 hexdig_init_D2A();
57 havedig = 0;
58 s0 = *(CONST unsigned char **)sp + 2;
59 while(s0[havedig] == '0')
60 havedig++;
61 s0 += havedig;
62 s = s0;
63 decpt = 0;
64 zret = 0;
65 e = 0;
66 if (!hexdig[*s]) {
67 zret = 1;
68 if (*s != decimalpoint)
69 goto pcheck;
70 decpt = ++s;
71 if (!hexdig[*s])
72 goto pcheck;
73 while(*s == '0')
74 s++;
75 if (hexdig[*s])
76 zret = 0;
77 havedig = 1;
78 s0 = s;
79 }
80 while(hexdig[*s])
81 s++;
82 if (*s == decimalpoint && !decpt) {
83 decpt = ++s;
84 while(hexdig[*s])
85 s++;
86 }
87 if (decpt)
88 e = -(((Long)(s-decpt)) << 2);
89 pcheck:
90 s1 = s;
91 switch(*s) {
92 case 'p':
93 case 'P':
94 esign = 0;
95 switch(*++s) {
96 case '-':
97 esign = 1;
98 /* FALLTHROUGH */
99 case '+':
100 s++;
101 }
102 if ((n = hexdig[*s]) == 0 || n > 0x19) {
103 s = s1;
104 break;
105 }
106 e1 = n - 0x10;
107 while((n = hexdig[*++s]) !=0 && n <= 0x19)
108 e1 = 10*e1 + n - 0x10;
109 if (esign)
110 e1 = -e1;
111 e += e1;
112 }
113 *sp = __UNCONST(s);
114 if (zret)
115 return havedig ? STRTOG_Zero : STRTOG_NoNumber;
116 n = (int)(s1 - s0 - 1);
117 for(k = 0; n > 7; n = (unsigned int)n >> 1)
118 k++;
119 b = Balloc(k);
120 if (b == NULL)
121 return STRTOG_NoMemory;
122 x = b->x;
123 n = 0;
124 L = 0;
125 while(s1 > s0) {
126 if (*--s1 == decimalpoint)
127 continue;
128 if (n == 32) {
129 *x++ = L;
130 L = 0;
131 n = 0;
132 }
133 L |= (hexdig[*s1] & 0x0f) << n;
134 n += 4;
135 }
136 *x++ = L;
137 b->wds = n = (int)(x - b->x);
138 n = 32*n - hi0bits(L);
139 nbits = fpi->nbits;
140 lostbits = 0;
141 x = b->x;
142 if (n > nbits) {
143 n -= nbits;
144 if (any_on(b,n)) {
145 lostbits = 1;
146 k = n - 1;
147 if (x[(unsigned int)k>>kshift] & 1 << (k & kmask)) {
148 lostbits = 2;
149 if (k > 1 && any_on(b,k-1))
150 lostbits = 3;
151 }
152 }
153 rshift(b, n);
154 e += n;
155 }
156 else if (n < nbits) {
157 n = nbits - n;
158 b = lshift(b, n);
159 if (b == NULL)
160 return STRTOG_NoMemory;
161 e -= n;
162 x = b->x;
163 }
164 if (e > fpi->emax) {
165 ovfl:
166 Bfree(b);
167 *bp = 0;
168 return STRTOG_Infinite | STRTOG_Overflow | STRTOG_Inexhi;
169 }
170 irv = STRTOG_Normal;
171 if (e < fpi->emin) {
172 irv = STRTOG_Denormal;
173 n = fpi->emin - e;
174 if (n >= nbits) {
175 switch (fpi->rounding) {
176 case FPI_Round_near:
177 if (n == nbits && (n < 2 || any_on(b,n-1)))
178 goto one_bit;
179 break;
180 case FPI_Round_up:
181 if (!sign)
182 goto one_bit;
183 break;
184 case FPI_Round_down:
185 if (sign) {
186 one_bit:
187 *expt = fpi->emin;
188 x[0] = b->wds = 1;
189 *bp = b;
190 return STRTOG_Denormal | STRTOG_Inexhi
191 | STRTOG_Underflow;
192 }
193 }
194 Bfree(b);
195 *bp = 0;
196 return STRTOG_Zero | STRTOG_Inexlo | STRTOG_Underflow;
197 }
198 k = n - 1;
199 if (lostbits)
200 lostbits = 1;
201 else if (k > 0)
202 lostbits = any_on(b,k);
203 if (x[(unsigned int)k>>kshift] & 1 << (k & kmask))
204 lostbits |= 2;
205 nbits -= n;
206 rshift(b,n);
207 e = fpi->emin;
208 }
209 if (lostbits) {
210 up = 0;
211 switch(fpi->rounding) {
212 case FPI_Round_zero:
213 break;
214 case FPI_Round_near:
215 if (lostbits & 2
216 && (lostbits & 1) | (x[0] & 1))
217 up = 1;
218 break;
219 case FPI_Round_up:
220 up = 1 - sign;
221 break;
222 case FPI_Round_down:
223 up = sign;
224 }
225 if (up) {
226 k = b->wds;
227 b = increment(b);
228 x = b->x;
229 if (irv == STRTOG_Denormal) {
230 if (nbits == fpi->nbits - 1
231 && x[(unsigned int)nbits >> kshift] & 1 << (nbits & kmask))
232 irv = STRTOG_Normal;
233 }
234 else if (b->wds > k
235 || ((n = nbits & kmask) !=0
236 && hi0bits(x[k-1]) < 32-n)) {
237 rshift(b,1);
238 if (++e > fpi->emax)
239 goto ovfl;
240 }
241 irv |= STRTOG_Inexhi;
242 }
243 else
244 irv |= STRTOG_Inexlo;
245 }
246 *bp = b;
247 *expt = e;
248 return irv;
249 }
250