Initial import of David Gay's gdtoa library for conversion betweenvendor/gdtoa/20030305

strings and floating point.

1 files changed, 242 insertions, 0 deletions

diff --git a/contrib/gdtoa/gethex.c b/contrib/gdtoa/gethex.c
new file mode 100644
index 000000000000..333f075932c9
--- /dev/null
+++ b/contrib/gdtoa/gethex.c
@@ -0,0 +1,242 @@
+/****************************************************************
+
+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
+	Bell Laboratories, Room 2C-463
+	600 Mountain Avenue
+	Murray Hill, NJ 07974-0636
+	U.S.A.
+	dmg@bell-labs.com
+ */
+
+#include "gdtoaimp.h"
+
+ int
+#ifdef KR_headers
+gethex(sp, fpi, exp, bp, sign)
+	CONST char **sp; FPI *fpi; Long *exp; Bigint **bp; int sign;
+#else
+gethex( CONST char **sp, FPI *fpi, Long *exp, Bigint **bp, int sign)
+#endif
+{
+	Bigint *b;
+	CONST unsigned char *decpt, *s0, *s, *s1;
+	int esign, havedig, irv, k, n, nbits, up;
+	ULong L, lostbits, *x;
+	Long e, e1;
+
+	if (!hexdig['0'])
+		hexdig_init_D2A();
+	havedig = 0;
+	s0 = *(CONST unsigned char **)sp + 2;
+	while(s0[havedig] == '0')
+		havedig++;
+	s0 += havedig;
+	s = s0;
+	decpt = 0;
+	if (!hexdig[*s]) {
+		if (*s == '.') {
+			decpt = ++s;
+			if (!hexdig[*s])
+				goto ret0;
+			}
+		else {
+ ret0:
+			*sp = (char*)s;
+			return havedig ? STRTOG_Zero : STRTOG_NoNumber;
+			}
+		while(*s == '0')
+			s++;
+		havedig = 1;
+		if (!hexdig[*s])
+			goto ret0;
+		s0 = s;
+		}
+	while(hexdig[*s])
+		s++;
+	if (*s == '.' && !decpt) {
+		decpt = ++s;
+		while(hexdig[*s])
+			s++;
+		}
+	e = 0;
+	if (decpt)
+		e = -(((Long)(s-decpt)) << 2);
+	s1 = s;
+	switch(*s) {
+	  case 'p':
+	  case 'P':
+		esign = 0;
+		switch(*++s) {
+		  case '-':
+			esign = 1;
+			/* no break */
+		  case '+':
+			s++;
+		  }
+		if ((n = hexdig[*s]) == 0 || n > 0x19) {
+			s = s1;
+			break;
+			}
+		e1 = n - 0x10;
+		while((n = hexdig[*++s]) !=0 && n <= 0x19)
+			e1 = 10*e1 + n - 0x10;
+		if (esign)
+			e1 = -e1;
+		e += e1;
+	  }
+	*sp = (char*)s;
+	n = s1 - s0 - 1;
+	for(k = 0; n > 7; n >>= 1)
+		k++;
+	b = Balloc(k);
+	x = b->x;
+	n = 0;
+	L = 0;
+	while(s1 > s0) {
+		if (*--s1 == '.')
+			continue;
+		if (n == 32) {
+			*x++ = L;
+			L = 0;
+			n = 0;
+			}
+		L |= (hexdig[*s1] & 0x0f) << n;
+		n += 4;
+		}
+	*x++ = L;
+	b->wds = n = x - b->x;
+	n = 32*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[k>>kshift] & 1 << (k & kmask)) {
+				lostbits = 2;
+				if (k > 1 && any_on(b,k-1))
+					lostbits = 3;
+				}
+			}
+		rshift(b, n);
+		e += n;
+		}
+	else if (n < nbits) {
+		n = nbits - n;
+		b = lshift(b, n);
+		e -= n;
+		x = b->x;
+		}
+	if (e > fpi->emax) {
+ ovfl:
+		Bfree(b);
+		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:
+					*exp = fpi->emin;
+					x[0] = b->wds = 1;
+					*bp = b;
+					return STRTOG_Denormal | STRTOG_Inexhi
+						| STRTOG_Underflow;
+					}
+			  }
+			Bfree(b);
+			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[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 & 1) | 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 (b->wds > k
+			 || (n = nbits & kmask) !=0
+			     && hi0bits(x[k-1]) < 32-n) {
+				rshift(b,1);
+				if (++e > fpi->emax)
+					goto ovfl;
+				}
+			else if (irv == STRTOG_Denormal) {
+				k = nbits - 1;
+				if (x[k >> kshift] & 1 << (k & kmask))
+					irv = STRTOG_Normal;
+				}
+			irv |= STRTOG_Inexhi;
+			}
+		else
+			irv |= STRTOG_Inexlo;
+		}
+	*bp = b;
+	*exp = e;
+	return irv;
+	}