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

The author of this software is David M. Gay.

Copyright (C) 1998-2001 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@acm.org

 */

#include "gdtoaimp.h"

#ifdef USE_LOCALE

#include "locale.h"

#endif

 static CONST int

fivesbits[] = {	 0,  3,  5,  7, 10, 12, 14, 17, 19, 21,

		24, 26, 28, 31, 33, 35, 38, 40, 42, 45,

		47, 49, 52

#ifdef VAX

		, 54, 56

#endif

		};

 Bigint *

#ifdef KR_headers

increment(b) Bigint *b;

#else

increment(Bigint *b)

#endif

{

	ULong *x, *xe;

	Bigint *b1;

#ifdef Pack_16

	ULong carry = 1, y;

#endif

	x = b->x;

	xe = x + b->wds;

#ifdef Pack_32

	do {

		if (*x < (ULong)0xffffffffL) {

			++*x;

			return b;

			}

		*x++ = 0;

		} while(x < xe);

#else

	do {

		y = *x + carry;

		carry = y >> 16;

		*x++ = y & 0xffff;

		if (!carry)

			return b;

		} while(x < xe);

	if (carry)

#endif

	{

		if (b->wds >= b->maxwds) {

			b1 = Balloc(b->k+1);

			Bcopy(b1,b);

			Bfree(b);

			b = b1;

			}

		b->x[b->wds++] = 1;

		}

	return b;

	}

 int

#ifdef KR_headers

decrement(b) Bigint *b;

#else

decrement(Bigint *b)

#endif

{

	ULong *x, *xe;

#ifdef Pack_16

	ULong borrow = 1, y;

#endif

	x = b->x;

	xe = x + b->wds;

#ifdef Pack_32

	do {

		if (*x) {

			--*x;

			break;

			}

		*x++ = 0xffffffffL;

		}

		while(x < xe);

#else

	do {

		y = *x - borrow;

		borrow = (y & 0x10000) >> 16;

		*x++ = y & 0xffff;

		} while(borrow && x < xe);

#endif

	return STRTOG_Inexlo;

	}

 static int

#ifdef KR_headers

all_on(b, n) Bigint *b; int n;

#else

all_on(Bigint *b, int n)

#endif

{

	ULong *x, *xe;

	x = b->x;

	xe = x + (n >> kshift);

	while(x < xe)

		if ((*x++ & ALL_ON) != ALL_ON)

			return 0;

	if (n &= kmask)

		return ((*x | (ALL_ON << n)) & ALL_ON) == ALL_ON;

	return 1;

	}

 Bigint *

#ifdef KR_headers

set_ones(b, n) Bigint *b; int n;

#else

set_ones(Bigint *b, int n)

#endif

{

	int k;

	ULong *x, *xe;

	k = (n + ((1 << kshift) - 1)) >> kshift;

	if (b->k < k) {

		Bfree(b);

		b = Balloc(k);

		}

	k = n >> kshift;

	if (n &= kmask)

		k++;

	b->wds = k;

	x = b->x;

	xe = x + k;

	while(x < xe)

		*x++ = ALL_ON;

	if (n)

		x[-1] >>= ULbits - n;

	return b;

	}

 static int

rvOK

#ifdef KR_headers

 (d, fpi, exp, bits, exact, rd, irv)

 double d; FPI *fpi; Long *exp; ULong *bits; int exact, rd, *irv;

#else

 (double d, FPI *fpi, Long *exp, ULong *bits, int exact, int rd, int *irv)

#endif

{

	Bigint *b;

	ULong carry, inex, lostbits;

	int bdif, e, j, k, k1, nb, rv;

	carry = rv = 0;

	b = d2b(d, &e, &bdif);

	bdif -= nb = fpi->nbits;

	e += bdif;

	if (bdif <= 0) {

		if (exact)

			goto trunc;

		goto ret;

		}

	if (P == nb) {

		if (

#ifndef IMPRECISE_INEXACT

			exact &&

#endif

			fpi->rounding ==

#ifdef RND_PRODQUOT

					FPI_Round_near

#else

					Flt_Rounds

#endif

			) goto trunc;

		goto ret;

		}

	switch(rd) {

	  case 1:

		goto trunc;

	  case 2:

		break;

	  default: /* round near */

		k = bdif - 1;

		if (k < 0)

			goto trunc;

		if (!k) {

			if (!exact)

				goto ret;

			if (b->x[0] & 2)

				break;

			goto trunc;

			}

		if (b->x[k>>kshift] & ((ULong)1 << (k & kmask)))

			break;

		goto trunc;

	  }

	/* "break" cases: round up 1 bit, then truncate; bdif > 0 */

	carry = 1;

 trunc:

	inex = lostbits = 0;

	if (bdif > 0) {

		if ( (lostbits = any_on(b, bdif)) !=0)

			inex = STRTOG_Inexlo;

		rshift(b, bdif);

		if (carry) {

			inex = STRTOG_Inexhi;

			b = increment(b);

			if ( (j = nb & kmask) !=0)

				j = 32 - j;

			if (hi0bits(b->x[b->wds - 1]) != j) {

				if (!lostbits)

					lostbits = b->x[0] & 1;

				rshift(b, 1);

				e++;

				}

			}

		}

	else if (bdif < 0)

		b = lshift(b, -bdif);

	if (e < fpi->emin) {

		k = fpi->emin - e;

		e = fpi->emin;

		if (k > nb || fpi->sudden_underflow) {

			b->wds = inex = 0;

			*irv = STRTOG_Underflow | STRTOG_Inexlo;

			}

		else {

			k1 = k - 1;

			if (k1 > 0 && !lostbits)

				lostbits = any_on(b, k1);

			if (!lostbits && !exact)

				goto ret;

			lostbits |=

			  carry = b->x[k1>>kshift] & (1 << (k1 & kmask));

			rshift(b, k);

			*irv = STRTOG_Denormal;

			if (carry) {

				b = increment(b);

				inex = STRTOG_Inexhi | STRTOG_Underflow;

				}

			else if (lostbits)

				inex = STRTOG_Inexlo | STRTOG_Underflow;

			}

		}

	else if (e > fpi->emax) {

		e = fpi->emax + 1;

		*irv = STRTOG_Infinite | STRTOG_Overflow | STRTOG_Inexhi;

#ifndef NO_ERRNO

		errno = ERANGE;

#endif

		b->wds = inex = 0;

		}

	*exp = e;

	copybits(bits, nb, b);

	*irv |= inex;

	rv = 1;

 ret:

	Bfree(b);

	return rv;

	}

 static int

#ifdef KR_headers

mantbits(d) double d;

#else

mantbits(double d)

#endif

{

	ULong L;

#ifdef VAX

	L = word1(d) << 16 | word1(d) >> 16;

	if (L)

#else

	if ( (L = word1(d)) !=0)

#endif

		return P - lo0bits(&L);

#ifdef VAX

	L = word0(d) << 16 | word0(d) >> 16 | Exp_msk11;

#else

	L = word0(d) | Exp_msk1;

#endif

	return P - 32 - lo0bits(&L);

	}

 int

strtodg

#ifdef KR_headers

	(s00, se, fpi, exp, bits)

	CONST char *s00; char **se; FPI *fpi; Long *exp; ULong *bits;

#else

	(CONST char *s00, char **se, FPI *fpi, Long *exp, ULong *bits)

#endif

{

	int abe, abits, asub;

	int bb0, bb2, bb5, bbe, bd2, bd5, bbbits, bs2;

	int c, denorm, dsign, e, e1, e2, emin, esign, finished, i, inex, irv;

	int j, k, nbits, nd, nd0, nf, nz, nz0, rd, rvbits, rve, rve1, sign;

	int sudden_underflow;

	CONST char *s, *s0, *s1;

	double adj, adj0, rv, tol;

	Long L;

	ULong y, z;

	Bigint *ab, *bb, *bb1, *bd, *bd0, *bs, *delta, *rvb, *rvb0;

	irv = STRTOG_Zero;

	denorm = sign = nz0 = nz = 0;

	dval(rv) = 0.;

	rvb = 0;

	nbits = fpi->nbits;

	for(s = s00;;s++) switch(*s) {

		case '-':

			sign = 1;

			/* no break */

		case '+':

			if (*++s)

				goto break2;

			/* no break */

		case 0:

			sign = 0;

			irv = STRTOG_NoNumber;

			s = s00;

			goto ret;

		case '\t':

		case '\n':

		case '\v':

		case '\f':

		case '\r':

		case ' ':

			continue;

		default:

			goto break2;

		}

 break2:

	if (*s == '0') {

#ifndef NO_HEX_FP

		switch(s[1]) {

		  case 'x':

		  case 'X':

			irv = gethex(&s, fpi, exp, &rvb, sign);

			if (irv == STRTOG_NoNumber) {

				s = s00;

				sign = 0;

				}

			goto ret;

		  }

#endif

		nz0 = 1;

		while(*++s == '0') ;

		if (!*s)

			goto ret;

		}

	sudden_underflow = fpi->sudden_underflow;

	s0 = s;

	y = z = 0;

	for(nd = nf = 0; (c = *s) >= '0' && c <= '9'; nd++, s++)

		if (nd < 9)

			y = 10*y + c - '0';

		else if (nd < 16)

			z = 10*z + c - '0';

	nd0 = nd;

#ifdef USE_LOCALE

	if (c == *localeconv()->decimal_point)

#else

	if (c == '.')

#endif

		{

		c = *++s;

		if (!nd) {

			for(; c == '0'; c = *++s)

				nz++;

			if (c > '0' && c <= '9') {

				s0 = s;

				nf += nz;

				nz = 0;

				goto have_dig;

				}

			goto dig_done;

			}

		for(; c >= '0' && c <= '9'; c = *++s) {

 have_dig:

			nz++;

			if (c -= '0') {

				nf += nz;

				for(i = 1; i < nz; i++)

					if (nd++ < 9)

						y *= 10;

					else if (nd <= DBL_DIG + 1)

						z *= 10;

				if (nd++ < 9)

					y = 10*y + c;

				else if (nd <= DBL_DIG + 1)

					z = 10*z + c;

				nz = 0;

				}

			}

		}

 dig_done:

	e = 0;

	if (c == 'e' || c == 'E') {

		if (!nd && !nz && !nz0) {

			irv = STRTOG_NoNumber;

			s = s00;

			goto ret;

			}

		s00 = s;

		esign = 0;

		switch(c = *++s) {

			case '-':

				esign = 1;

			case '+':

				c = *++s;

			}

		if (c >= '0' && c <= '9') {

			while(c == '0')

				c = *++s;

			if (c > '0' && c <= '9') {

				L = c - '0';

				s1 = s;

				while((c = *++s) >= '0' && c <= '9')

					L = 10*L + c - '0';

				if (s - s1 > 8 || L > 19999)

					/* Avoid confusion from exponents

					 * so large that e might overflow.

					 */

					e = 19999; /* safe for 16 bit ints */

				else

					e = (int)L;

				if (esign)

					e = -e;

				}

			else

				e = 0;

			}

		else

			s = s00;

		}

	if (!nd) {

		if (!nz && !nz0) {

#ifdef INFNAN_CHECK

			/* Check for Nan and Infinity */

			switch(c) {

			  case 'i':

			  case 'I':

				if (match(&s,"nf")) {

					--s;

					if (!match(&s,"inity"))

						++s;

					irv = STRTOG_Infinite;

					goto infnanexp;

					}

				break;

			  case 'n':

			  case 'N':

				if (match(&s, "an")) {

					irv = STRTOG_NaN;

					*exp = fpi->emax + 1;

#ifndef No_Hex_NaN

					if (*s == '(') /*)*/

						irv = hexnan(&s, fpi, bits);

#endif

					goto infnanexp;

					}

			  }

#endif /* INFNAN_CHECK */

			irv = STRTOG_NoNumber;

			s = s00;

			}

		goto ret;

		}

	irv = STRTOG_Normal;

	e1 = e -= nf;

	rd = 0;

	switch(fpi->rounding & 3) {

	  case FPI_Round_up:

		rd = 2 - sign;

		break;

	  case FPI_Round_zero:

		rd = 1;

		break;

	  case FPI_Round_down:

		rd = 1 + sign;

	  }

	/* Now we have nd0 digits, starting at s0, followed by a

	 * decimal point, followed by nd-nd0 digits.  The number we're

	 * after is the integer represented by those digits times

	 * 10**e */

	if (!nd0)

		nd0 = nd;

	k = nd < DBL_DIG + 1 ? nd : DBL_DIG + 1;

	dval(rv) = y;

	if (k > 9)

		dval(rv) = tens[k - 9] * dval(rv) + z;