econvert.c

操作系统SunOS 4.1.3版本的源码

#if !defined(lint) && defined(SCCSIDS)
static char     sccsid[] = "@(#)econvert.c 1.1 92/07/30 SMI";
#endif

/*
 * Copyright (c) 1988 by Sun Microsystems, Inc.
 */

#include "base_conversion.h"

static char     *nanstring = "NaN";
static char     *infstring = "Infinity";

char           *
econvert(arg, ndigits, decpt, sign, buf)
	double          arg;
	int             ndigits, *decpt, *sign;
	char           *buf;
{
	decimal_mode    dm;
	decimal_record  dr;
	fp_exception_field_type ef;
	int             i;
	char           *pc;
	int             nc;

	dm.rd = fp_direction;	/* Rounding direction. */
	dm.df = floating_form;	/* E format. */
	dm.ndigits = ndigits;	/* Number of significant digits. */
	double_to_decimal(&arg, &dm, &dr, &ef);
	*sign = dr.sign;
	switch (dr.fpclass) {
	case fp_normal:
	case fp_subnormal:
		*decpt = dr.exponent + ndigits;
		for (i = 0; i < ndigits; i++)
			buf[i] = dr.ds[i];
		buf[ndigits] = 0;
		break;
	case fp_zero:
		*decpt = 1;
		for (i = 0; i < ndigits; i++)
			buf[i] = '0';
		buf[ndigits] = 0;
		break;
	case fp_infinity:
		*decpt = 0;
		pc = infstring;
		if (ndigits < 8)
			nc = 3;
		else
			nc = 8;
		goto movestring;
	case fp_quiet:
	case fp_signaling:
		*decpt = 0;
		pc = nanstring;
		nc = 3;
movestring:
		for (i = 0; i < nc; i++)
			buf[i] = pc[i];
		buf[nc] = 0;
		break;
	}
	return buf;		/* For compatibility with ecvt. */
}

char           *
fconvert(arg, ndigits, decpt, sign, buf)
	double          arg;
	int             ndigits, *decpt, *sign;
	char           *buf;
{
	decimal_mode    dm;
	decimal_record  dr;
	fp_exception_field_type ef;
	int             i;
	char           *pc;
	int             nc;

	dm.rd = fp_direction;	/* Rounding direction. */
	dm.df = fixed_form;	/* F format. */
	dm.ndigits = ndigits;	/* Number of digits after point. */
	double_to_decimal(&arg, &dm, &dr, &ef);
	*sign = dr.sign;
	switch (dr.fpclass) {
	case fp_normal:
	case fp_subnormal:
		if (ndigits >= 0)
			*decpt = dr.ndigits - ndigits;
		else
			*decpt = dr.ndigits;
		for (i = 0; i < dr.ndigits; i++)
			buf[i] = dr.ds[i];
		buf[dr.ndigits] = 0;
		break;
	case fp_zero:
		*decpt = 0;
		buf[0] = '0';
		for (i = 1; i < ndigits; i++)
			buf[i] = '0';
		buf[i] = 0;
		break;
	case fp_infinity:
		*decpt = 0;
		pc = infstring;
		if (ndigits < 8)
			nc = 3;
		else
			nc = 8;
		goto movestring;
	case fp_quiet:
	case fp_signaling:
		*decpt = 0;
		pc = nanstring;
		nc = 3;
movestring:
		for (i = 0; i < nc; i++)
			buf[i] = pc[i];
		buf[nc] = 0;
		break;
	}
	return buf;		/* For compatibility with fcvt. */
}