/*

 * gawk wrapper for strtod

 */

/*

 * Stupid version of System V strtod(3) library routine.

 * Does no overflow/underflow checking.

 *

 * A real number is defined to be

 *	optional leading white space

 *	optional sign

 *	string of digits with optional decimal point

 *	optional 'e' or 'E'

 *		followed by optional sign or space

 *		followed by an integer

 *

 * if ptr is not NULL a pointer to the character terminating the

 * scan is returned in *ptr.  If no number formed, *ptr is set to str

 * and 0 is returned.

 *

 * For speed, we don't do the conversion ourselves.  Instead, we find

 * the end of the number and then call atof() to do the dirty work.

 * This bought us a 10% speedup on a sample program at uunet.uu.net.

 *

 * Fall 2000: Changed to enforce C89 semantics, so that 0x... returns 0.

 * C99 has hexadecimal floating point numbers.

 *

 * Summer 2001. Try to make it smarter, so that a string like "0000"

 * doesn't look like we failed. Sigh.

 *

 * Xmass 2002. Fix a bug in ptr determination, eg. for "0e0".

 *

 * Spring 2004. Update for I18N. Oh joy.

 */

#if 0

#include <ctype.h>

#endif

extern double atof();

double

gawk_strtod(s, ptr)

const char *s;

const char **ptr;

{

	const char *start = s;		/* save original start of string */

	const char *begin = NULL;	/* where the number really begins */

	int dig = 0;

	int dig0 = 0;

	/* optional white space */

	while (isspace(*s))

		s++;

	begin = s;

	/* optional sign */

	if (*s == '+' || *s == '-')

		s++;

	/* string of digits with optional decimal point */

	while (*s == '0') {

		s++;

		dig0++;

	}

	while (isdigit(*s)) {

		s++;

		dig++;

	}

	if (

#if defined(HAVE_LOCALE_H)

	loc.decimal_point != NULL && do_posix

			? *s == loc.decimal_point[0]

			: *s == '.'

#else

	*s == '.'

#endif

	) {

		s++;

		while (*s == '0') {

			s++;

			dig0++;

		}

		while (isdigit(*s)) {

			s++;

			dig++;

		}

	}

	dig0 += dig;	/* any digit has appeared */

	/*

 	 *	optional 'e' or 'E'

	 *		if a digit (or at least zero) was seen

	 *		followed by optional sign

	 *		followed by an integer

	 */

	if (dig0

	    && (*s == 'e' || *s == 'E')

	    && (isdigit(s[1])

	      || ((s[1] == '-' || s[1] == '+') && isdigit(s[2])))) {

		s++;

		if (*s == '+' || *s == '-')

			s++;

		while (isdigit(*s))

			s++;

	}

	/* In case we haven't found a number, set ptr to start. */

	if (ptr)

		*ptr = (dig0 ? s : start);

	/* Go for it. */

	return (dig ? atof(begin) : 0.0);

}

#ifdef TEST

int

main(argc, argv)

int argc;

char **argv;

{

	double d;

	char *p;

	for (argc--, argv++; argc; argc--, argv++) {

		d = strtod (*argv, & p);

		printf ("%lf [%s]\n", d, p);

	}

	return 0;

}

#endif