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19927830ac
denormal and locale handling in strtod().
250 lines
5.0 KiB
C
250 lines
5.0 KiB
C
/****************************************************************
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The author of this software is David M. Gay.
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Copyright (C) 1998 by Lucent Technologies
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and
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its documentation for any purpose and without fee is hereby
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granted, provided that the above copyright notice appear in all
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copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the name of Lucent or any of its entities
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not be used in advertising or publicity pertaining to
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distribution of the software without specific, written prior
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permission.
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LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
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IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
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SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
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IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
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ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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THIS SOFTWARE.
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****************************************************************/
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/* Please send bug reports to
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David M. Gay
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dmg@acm.org
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*/
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#include "gdtoaimp.h"
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#ifdef USE_LOCALE
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#include "locale.h"
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#endif
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int
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#ifdef KR_headers
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gethex(sp, fpi, exp, bp, sign)
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CONST char **sp; FPI *fpi; Long *exp; Bigint **bp; int sign;
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#else
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gethex( CONST char **sp, FPI *fpi, Long *exp, Bigint **bp, int sign)
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#endif
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{
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Bigint *b;
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CONST unsigned char *decpt, *s0, *s, *s1;
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int esign, havedig, irv, k, n, nbits, up;
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ULong L, lostbits, *x;
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Long e, e1;
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#ifdef USE_LOCALE
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unsigned char decimalpoint = *localeconv()->decimal_point;
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#else
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#define decimalpoint '.'
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#endif
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if (!hexdig['0'])
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hexdig_init_D2A();
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havedig = 0;
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s0 = *(CONST unsigned char **)sp + 2;
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while(s0[havedig] == '0')
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havedig++;
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s0 += havedig;
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s = s0;
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decpt = 0;
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if (!hexdig[*s]) {
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if (*s == decimalpoint) {
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decpt = ++s;
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if (!hexdig[*s])
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goto ret0;
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}
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else {
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ret0:
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*sp = (char*)s;
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return havedig ? STRTOG_Zero : STRTOG_NoNumber;
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}
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while(*s == '0')
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s++;
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havedig = 1;
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if (!hexdig[*s])
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goto ret0;
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s0 = s;
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}
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while(hexdig[*s])
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s++;
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if (*s == decimalpoint && !decpt) {
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decpt = ++s;
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while(hexdig[*s])
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s++;
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}
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e = 0;
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if (decpt)
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e = -(((Long)(s-decpt)) << 2);
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s1 = s;
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switch(*s) {
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case 'p':
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case 'P':
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esign = 0;
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switch(*++s) {
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case '-':
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esign = 1;
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/* no break */
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case '+':
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s++;
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}
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if ((n = hexdig[*s]) == 0 || n > 0x19) {
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s = s1;
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break;
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}
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e1 = n - 0x10;
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while((n = hexdig[*++s]) !=0 && n <= 0x19)
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e1 = 10*e1 + n - 0x10;
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if (esign)
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e1 = -e1;
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e += e1;
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}
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*sp = (char*)s;
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n = s1 - s0 - 1;
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for(k = 0; n > 7; n >>= 1)
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k++;
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b = Balloc(k);
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x = b->x;
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n = 0;
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L = 0;
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while(s1 > s0) {
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if (*--s1 == decimalpoint)
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continue;
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if (n == 32) {
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*x++ = L;
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L = 0;
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n = 0;
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}
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L |= (hexdig[*s1] & 0x0f) << n;
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n += 4;
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}
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*x++ = L;
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b->wds = n = x - b->x;
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n = 32*n - hi0bits(L);
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nbits = fpi->nbits;
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lostbits = 0;
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x = b->x;
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if (n > nbits) {
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n -= nbits;
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if (any_on(b,n)) {
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lostbits = 1;
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k = n - 1;
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if (x[k>>kshift] & 1 << (k & kmask)) {
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lostbits = 2;
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if (k > 1 && any_on(b,k-1))
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lostbits = 3;
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}
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}
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rshift(b, n);
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e += n;
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}
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else if (n < nbits) {
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n = nbits - n;
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b = lshift(b, n);
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e -= n;
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x = b->x;
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}
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if (e > fpi->emax) {
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ovfl:
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Bfree(b);
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*bp = 0;
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return STRTOG_Infinite | STRTOG_Overflow | STRTOG_Inexhi;
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}
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irv = STRTOG_Normal;
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if (e < fpi->emin) {
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irv = STRTOG_Denormal;
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n = fpi->emin - e;
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if (n >= nbits) {
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switch (fpi->rounding) {
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case FPI_Round_near:
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if (n == nbits && (n < 2 || any_on(b,n-1)))
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goto one_bit;
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break;
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case FPI_Round_up:
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if (!sign)
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goto one_bit;
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break;
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case FPI_Round_down:
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if (sign) {
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one_bit:
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*exp = fpi->emin;
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x[0] = b->wds = 1;
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*bp = b;
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return STRTOG_Denormal | STRTOG_Inexhi
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| STRTOG_Underflow;
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}
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}
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Bfree(b);
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*bp = 0;
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return STRTOG_Zero | STRTOG_Inexlo | STRTOG_Underflow;
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}
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k = n - 1;
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if (lostbits)
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lostbits = 1;
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else if (k > 0)
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lostbits = any_on(b,k);
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if (x[k>>kshift] & 1 << (k & kmask))
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lostbits |= 2;
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nbits -= n;
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rshift(b,n);
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e = fpi->emin;
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}
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if (lostbits) {
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up = 0;
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switch(fpi->rounding) {
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case FPI_Round_zero:
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break;
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case FPI_Round_near:
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if (lostbits & 2
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&& (lostbits & 1) | x[0] & 1)
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up = 1;
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break;
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case FPI_Round_up:
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up = 1 - sign;
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break;
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case FPI_Round_down:
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up = sign;
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}
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if (up) {
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k = b->wds;
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b = increment(b);
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x = b->x;
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if (irv == STRTOG_Denormal) {
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if (nbits == fpi->nbits - 1
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&& x[nbits >> kshift] & 1 << (nbits & kmask))
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irv = STRTOG_Normal;
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}
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else if (b->wds > k
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|| (n = nbits & kmask) !=0
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&& hi0bits(x[k-1]) < 32-n) {
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rshift(b,1);
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if (++e > fpi->emax)
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goto ovfl;
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}
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irv |= STRTOG_Inexhi;
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}
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else
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irv |= STRTOG_Inexlo;
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}
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*bp = b;
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*exp = e;
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return irv;
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}
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