xref: /src/lib/libc/gdtoa/gethex.c

/* $NetBSD: gethex.c,v 1.5 2011/03/20 23:15:35 christos Exp $ */

/****************************************************************

The author of this software is David M. Gay.

Copyright (C) 1998 by Lucent Technologies
All Rights Reserved

Permission to use, copy, modify, and distribute this software and
its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appear in all
copies and that both that the copyright notice and this
permission notice and warranty disclaimer appear in supporting
documentation, and that the name of Lucent or any of its entities
not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior
permission.

LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
THIS SOFTWARE.

****************************************************************/

/* Please send bug reports to David M. Gay (dmg at acm dot org,
 * with " at " changed at "@" and " dot " changed to ".").	*/

#include "gdtoaimp.h"

#ifdef USE_LOCALE
#include "locale.h"
#endif

 int
#ifdef KR_headers
gethex(sp, fpi, expt, bp, sign)
	CONST char **sp; CONST FPI *fpi; Long *expt; Bigint **bp; int sign;
#else
gethex( CONST char **sp, CONST FPI *fpi, Long *expt, Bigint **bp, int sign)
#endif
{
	Bigint *b;
	CONST char *decpt, *s, *s0, *s1;
	int big, esign, havedig, irv, j, k, n, n0, nbits, up, zret;
	ULong L, lostbits, *x;
	Long e, e1;
#ifdef USE_LOCALE
	int i;
#ifdef NO_LOCALE_CACHE
	const char *decimalpoint = localeconv()->decimal_point;
#else
	const unsigned char *decimalpoint;
	static char *decimalpoint_cache;
	if (!(s0 = decimalpoint_cache)) {
		s0 = localeconv()->decimal_point;
		if ((decimalpoint_cache = MALLOC(strlen(s0) + 1)) != NULL) {
			strcpy(decimalpoint_cache, s0);
			s0 = decimalpoint_cache;
			}
		}
	decimalpoint = __UNCONST(s0);
#endif
#endif

	if (!hexdig[(unsigned char)'0'])
		hexdig_init_D2A();
	*bp = 0;
	havedig = 0;
	s0 = *(CONST char **)sp + 2;
	while(s0[havedig] == '0')
		havedig++;
	s0 += havedig;
	s = s0;
	decpt = 0;
	zret = 0;
	e = 0;
	if (hexdig[(unsigned char)*s])
		havedig++;
	else {
		zret = 1;
#ifdef USE_LOCALE
		for(i = 0; decimalpoint[i]; ++i) {
			if (s[i] != decimalpoint[i])
				goto pcheck;
			}
		decpt = s += i;
#else
		if (*s != '.')
			goto pcheck;
		decpt = ++s;
#endif
		if (!hexdig[(unsigned char)*s])
			goto pcheck;
		while(*s == '0')
			s++;
		if (hexdig[(unsigned char)*s])
			zret = 0;
		havedig = 1;
		s0 = s;
		}
	while(hexdig[(unsigned char)*s])
		s++;
#ifdef USE_LOCALE
	if (*s == *decimalpoint && !decpt) {
		for(i = 1; decimalpoint[i]; ++i) {
			if (s[i] != decimalpoint[i])
				goto pcheck;
			}
		decpt = s += i;
#else
	if (*s == '.' && !decpt) {
		decpt = ++s;
#endif
		while(hexdig[(unsigned char)*s])
			s++;
		}/*}*/
	if (decpt)
		e = -(((Long)(s-decpt)) << 2);
 pcheck:
	s1 = s;
	big = esign = 0;
	switch(*s) {
	  case 'p':
	  case 'P':
		switch(*++s) {
		  case '-':
			esign = 1;
			/* FALLTHROUGH */
		  case '+':
			s++;
		  }
		if ((n = hexdig[(unsigned char)*s]) == 0 || n > 0x19) {
			s = s1;
			break;
			}
		e1 = n - 0x10;
		while((n = hexdig[(unsigned char)*++s]) !=0 && n <= 0x19) {
			if (e1 & 0xf8000000)
				big = 1;
			e1 = 10*e1 + n - 0x10;
			}
		if (esign)
			e1 = -e1;
		e += e1;
	  }
	*sp = __UNCONST(s);
	if (!havedig)
		*sp = (char*)__UNCONST(s0) - 1;
	if (zret)
		return STRTOG_Zero;
	if (big) {
		if (esign) {
			switch(fpi->rounding) {
			  case FPI_Round_up:
				if (sign)
					break;
				goto ret_tiny;
			  case FPI_Round_down:
				if (!sign)
					break;
				goto ret_tiny;
			  }
			goto retz;
 ret_tiny:
			b = Balloc(0);
			b->wds = 1;
			b->x[0] = 1;
			goto dret;
			}
		switch(fpi->rounding) {
		  case FPI_Round_near:
			goto ovfl1;
		  case FPI_Round_up:
			if (!sign)
				goto ovfl1;
			goto ret_big;
		  case FPI_Round_down:
			if (sign)
				goto ovfl1;
			goto ret_big;
		  }
 ret_big:
		nbits = fpi->nbits;
		n0 = n = (unsigned int)nbits >> kshift;
		if (nbits & kmask)
			++n;
		for(j = n, k = 0; (j = (unsigned int)j >> 1) != 0; ++k);
		*bp = b = Balloc(k);
		b->wds = n;
		for(j = 0; j < n0; ++j)
			b->x[j] = ALL_ON;
		if (n > n0)
			b->x[j] = ULbits >> (ULbits - (nbits & kmask));
		*expt = fpi->emin;
		return STRTOG_Normal | STRTOG_Inexlo;
		}
	n = (int)(s1 - s0) - 1;
	for(k = 0; n > (1 << (kshift-2)) - 1; n = (unsigned int)n >> 1)
		k++;
	b = Balloc(k);
	if (b == NULL)
		return STRTOG_NoMemory;
	x = b->x;
	n = 0;
	L = 0;
#ifdef USE_LOCALE
	for(i = 0; decimalpoint[i+1]; ++i);
#endif
	while(s1 > s0) {
#ifdef USE_LOCALE
		if (*--s1 == decimalpoint[i]) {
			s1 -= i;
			continue;
			}
#else
		if (*--s1 == '.')
			continue;
#endif
		if (n == ULbits) {
			*x++ = L;
			L = 0;
			n = 0;
			}
		L |= (hexdig[(unsigned char)*s1] & 0x0f) << n;
		n += 4;
		}
	*x++ = L;
	b->wds = n = (int)(x - b->x);
	n = ULbits*n - hi0bits(L);
	nbits = fpi->nbits;
	lostbits = 0;
	x = b->x;
	if (n > nbits) {
		n -= nbits;
		if (any_on(b,n)) {
			lostbits = 1;
			k = n - 1;
			if (x[(unsigned int)k>>kshift] & 1 << (k & kmask)) {
				lostbits = 2;
				if (k > 0 && any_on(b,k))
					lostbits = 3;
				}
			}
		rshift(b, n);
		e += n;
		}
	else if (n < nbits) {
		n = nbits - n;
		b = lshift(b, n);
		if (b == NULL)
			return STRTOG_NoMemory;
		e -= n;
		x = b->x;
		}
	if (e > fpi->emax) {
 ovfl:
		Bfree(b);
 ovfl1:
#ifndef NO_ERRNO
		errno = ERANGE;
#endif
		return STRTOG_Infinite | STRTOG_Overflow | STRTOG_Inexhi;
		}
	irv = STRTOG_Normal;
	if (e < fpi->emin) {
		irv = STRTOG_Denormal;
		n = fpi->emin - e;
		if (n >= nbits) {
			switch (fpi->rounding) {
			  case FPI_Round_near:
				if (n == nbits && (n < 2 || any_on(b,n-1)))
					goto one_bit;
				break;
			  case FPI_Round_up:
				if (!sign)
					goto one_bit;
				break;
			  case FPI_Round_down:
				if (sign) {
 one_bit:
					x[0] = b->wds = 1;
 dret:
					*bp = b;
					*expt = fpi->emin;
#ifndef NO_ERRNO
					errno = ERANGE;
#endif
					return STRTOG_Denormal | STRTOG_Inexhi
						| STRTOG_Underflow;
					}
			  }
			Bfree(b);
 retz:
#ifndef NO_ERRNO
			errno = ERANGE;
#endif
			return STRTOG_Zero | STRTOG_Inexlo | STRTOG_Underflow;
			}
		k = n - 1;
		if (lostbits)
			lostbits = 1;
		else if (k > 0)
			lostbits = any_on(b,k);
		if (x[(unsigned int)k>>kshift] & 1 << (k & kmask))
			lostbits |= 2;
		nbits -= n;
		rshift(b,n);
		e = fpi->emin;
		}
	if (lostbits) {
		up = 0;
		switch(fpi->rounding) {
		  case FPI_Round_zero:
			break;
		  case FPI_Round_near:
			if (lostbits & 2
			 && (lostbits | x[0]) & 1)
				up = 1;
			break;
		  case FPI_Round_up:
			up = 1 - sign;
			break;
		  case FPI_Round_down:
			up = sign;
		  }
		if (up) {
			k = b->wds;
			b = increment(b);
			x = b->x;
			if (irv == STRTOG_Denormal) {
				if (nbits == fpi->nbits - 1
				 && x[(unsigned int)nbits >> kshift] & 1 << (nbits & kmask))
					irv =  STRTOG_Normal;
				}
			else if (b->wds > k
			 || ((n = nbits & kmask) !=0
			      && hi0bits(x[k-1]) < 32-n)) {
				rshift(b,1);
				if (++e > fpi->emax)
					goto ovfl;
				}
			irv |= STRTOG_Inexhi;
			}
		else
			irv |= STRTOG_Inexlo;
		}
	*bp = b;
	*expt = e;
	return irv;
	}