snprintf.c

-

/*
 * $Id: snprintf.c,v 1.16.6.1 1999/02/12 19:38:15 wessels Exp $
 */

/* ====================================================================
 * Copyright (c) 1995-1997 The Apache Group.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * 4. The names "Apache Server" and "Apache Group" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission.
 *
 * 5. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE APACHE GROUP OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Group and was originally based
 * on public domain software written at the National Center for
 * Supercomputing Applications, University of Illinois, Urbana-Champaign.
 * For more information on the Apache Group and the Apache HTTP server
 * project, please see <http://www.apache.org/>.
 *
 * This code is based on, and used with the permission of, the
 * SIO stdio-replacement strx_* functions by Panos Tsirigotis
 * <[e-mail]> for xinetd.
 */

#include "config.h"
#if !HAVE_SNPRINTF || !HAVE_VSNPRINTF

#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <assert.h>

#ifdef HAVE_CVT

#define ap_ecvt ecvt
#define ap_fcvt fcvt
#define ap_gcvt gcvt

#else

/*
 * cvt.c - IEEE floating point formatting routines for FreeBSD
 * from GNU libc-4.6.27
 */

/*
 *    ap_ecvt converts to decimal
 *      the number of digits is specified by ndigit
 *      decpt is set to the position of the decimal point
 *      sign is set to 0 for positive, 1 for negative
 */

#define	NDIG	80

static char *
ap_cvt(double arg, int ndigits, int *decpt, int *sign, int eflag)
{
    register int r2;
    double fi, fj;
    register char *p, *p1;
    static char buf[NDIG];

    if (ndigits >= NDIG - 1)
	ndigits = NDIG - 2;
    r2 = 0;
    *sign = 0;
    p = &buf[0];
    if (arg < 0) {
	*sign = 1;
	arg = -arg;
    }
    arg = modf(arg, &fi);
    p1 = &buf[NDIG];
    /*
     * Do integer part
     */
    if (fi != 0) {
	p1 = &buf[NDIG];
	while (fi != 0) {
	    fj = modf(fi / 10, &fi);
	    *--p1 = (int) ((fj + .03) * 10) + '0';
	    r2++;
	}
	while (p1 < &buf[NDIG])
	    *p++ = *p1++;
    } else if (arg > 0) {
	while ((fj = arg * 10) < 1) {
	    arg = fj;
	    r2--;
	}
    }
    p1 = &buf[ndigits];
    if (eflag == 0)
	p1 += r2;
    *decpt = r2;
    if (p1 < &buf[0]) {
	buf[0] = '\0';
	return (buf);
    }
    while (p <= p1 && p < &buf[NDIG]) {
	arg *= 10;
	arg = modf(arg, &fj);
	*p++ = (int) fj + '0';
    }
    if (p1 >= &buf[NDIG]) {
	buf[NDIG - 1] = '\0';
	return (buf);
    }
    p = p1;
    *p1 += 5;
    while (*p1 > '9') {
	*p1 = '0';
	if (p1 > buf)
	    ++ * --p1;
	else {
	    *p1 = '1';
	    (*decpt)++;
	    if (eflag == 0) {
		if (p > buf)
		    *p = '0';
		p++;
	    }
	}
    }
    *p = '\0';
    return (buf);
}

static char *
ap_ecvt(double arg, int ndigits, int *decpt, int *sign)
{
    return (ap_cvt(arg, ndigits, decpt, sign, 1));
}

static char *
ap_fcvt(double arg, int ndigits, int *decpt, int *sign)
{
    return (ap_cvt(arg, ndigits, decpt, sign, 0));
}

/*
 * ap_gcvt  - Floating output conversion to
 * minimal length string
 */

static char *
ap_gcvt(double number, int ndigit, char *buf)
{
    int sign, decpt;
    register char *p1, *p2;
    register int i;

    p1 = ap_ecvt(number, ndigit, &decpt, &sign);
    p2 = buf;
    if (sign)
	*p2++ = '-';
    for (i = ndigit - 1; i > 0 && p1[i] == '0'; i--)
	ndigit--;
    if ((decpt >= 0 && decpt - ndigit > 4)
	|| (decpt < 0 && decpt < -3)) {		/* use E-style */
	decpt--;
	*p2++ = *p1++;
	*p2++ = '.';
	for (i = 1; i < ndigit; i++)
	    *p2++ = *p1++;
	*p2++ = 'e';
	if (decpt < 0) {
	    decpt = -decpt;
	    *p2++ = '-';
	} else
	    *p2++ = '+';
	if (decpt / 100 > 0)
	    *p2++ = decpt / 100 + '0';
	if (decpt / 10 > 0)
	    *p2++ = (decpt % 100) / 10 + '0';
	*p2++ = decpt % 10 + '0';
    } else {
	if (decpt <= 0) {
	    if (*p1 != '0')
		*p2++ = '.';
	    while (decpt < 0) {
		decpt++;
		*p2++ = '0';
	    }
	}
	for (i = 1; i <= ndigit; i++) {
	    *p2++ = *p1++;
	    if (i == decpt)
		*p2++ = '.';
	}
	if (ndigit < decpt) {
	    while (ndigit++ < decpt)
		*p2++ = '0';
	    *p2++ = '.';
	}
    }
    if (p2[-1] == '.')
	p2--;
    *p2 = '\0';
    return (buf);
}

#endif /* HAVE_CVT */

typedef enum {
    NO = 0, YES = 1
} boolean_e;

#define FALSE			0
#define TRUE			1
#define NUL			'\0'
#define INT_NULL		((int *)0)
#define WIDE_INT		long

typedef WIDE_INT wide_int;
typedef unsigned WIDE_INT u_wide_int;
typedef int bool_int;

#define S_NULL			"(null)"
#define S_NULL_LEN		6

#define FLOAT_DIGITS		6
#define EXPONENT_LENGTH		10

/*
 * NUM_BUF_SIZE is the size of the buffer used for arithmetic conversions
 *
 * XXX: this is a magic number; do not decrease it
 */
#define NUM_BUF_SIZE		512


/*
 * Descriptor for buffer area
 */
struct buf_area {
    char *buf_end;
    char *nextb;		/* pointer to next byte to read/write   */
};

typedef struct buf_area buffy;

/*
 * The INS_CHAR macro inserts a character in the buffer and writes
 * the buffer back to disk if necessary
 * It uses the char pointers sp and bep:
 *      sp points to the next available character in the buffer
 *      bep points to the end-of-buffer+1
 * While using this macro, note that the nextb pointer is NOT updated.
 *
 * NOTE: Evaluation of the c argument should not have any side-effects
 */
#define INS_CHAR( c, sp, bep, cc )	\
	    {				\
		if ( sp < bep )		\
		{			\
		    *sp++ = c ;		\
		    cc++ ;		\
		}			\
	    }

#define NUM( c )			( c - '0' )

#define STR_TO_DEC( str, num )		\
    num = NUM( *str++ ) ;		\
    while ( xisdigit( *str ) )		\
    {					\
	num *= 10 ;			\
	num += NUM( *str++ ) ;		\
    }

/*
 * This macro does zero padding so that the precision
 * requirement is satisfied. The padding is done by
 * adding '0's to the left of the string that is going
 * to be printed.
 */
#define FIX_PRECISION( adjust, precision, s, s_len )	\
    if ( adjust )					\
	while ( s_len < precision )			\
	{						\
	    *--s = '0' ;				\
	    s_len++ ;					\
	}

/*
 * Macro that does padding. The padding is done by printing
 * the character ch.
 */
#define PAD( width, len, ch )	do		\
	{					\
	    INS_CHAR( ch, sp, bep, cc ) ;	\
	    width-- ;				\
	}					\
	while ( width > len )

/*
 * Prefix the character ch to the string str
 * Increase length
 * Set the has_prefix flag
 */
#define PREFIX( str, length, ch )	 *--str = ch ; length++ ; has_prefix = YES


/*
 * Convert num to its decimal format.
 * Return value:
 *   - a pointer to a string containing the number (no sign)
 *   - len contains the length of the string
 *   - is_negative is set to TRUE or FALSE depending on the sign
 *     of the number (always set to FALSE if is_unsigned is TRUE)
 *
 * The caller provides a buffer for the string: that is the buf_end argument
 * which is a pointer to the END of the buffer + 1 (i.e. if the buffer
 * is declared as buf[ 100 ], buf_end should be &buf[ 100 ])
 */
static char *
conv_10(register wide_int num, register bool_int is_unsigned,
    register bool_int * is_negative, char *buf_end, register int *len)
{
    register char *p = buf_end;
    register u_wide_int magnitude;

    if (is_unsigned) {
	magnitude = (u_wide_int) num;
	*is_negative = FALSE;
    } else {
	*is_negative = (num < 0);

	/*
	 * On a 2's complement machine, negating the most negative integer 
	 * results in a number that cannot be represented as a signed integer.
	 * Here is what we do to obtain the number's magnitude:
	 *      a. add 1 to the number
	 *      b. negate it (becomes positive)
	 *      c. convert it to unsigned
	 *      d. add 1
	 */
	if (*is_negative) {
	    wide_int t = num + 1;

	    magnitude = ((u_wide_int) - t) + 1;
	} else
	    magnitude = (u_wide_int) num;
    }

    /*
     * We use a do-while loop so that we write at least 1 digit 
     */
    do {
	register u_wide_int new_magnitude = magnitude / 10;

	*--p = (char) (magnitude - new_magnitude * 10 + '0');
	magnitude = new_magnitude;
    }
    while (magnitude);

    *len = buf_end - p;
    return (p);
}



/*
 * Convert a floating point number to a string formats 'f', 'e' or 'E'.
 * The result is placed in buf, and len denotes the length of the string
 * The sign is returned in the is_negative argument (and is not placed
 * in buf).
 */
static char *
conv_fp(register char format, register double num,
    boolean_e add_dp, int precision, bool_int * is_negative, char *buf, int *len)
{
    register char *s = buf;
    register char *p;
    int decimal_point;

    if (format == 'f')
	p = ap_fcvt(num, precision, &decimal_point, is_negative);
    else			/* either e or E format */
	p = ap_ecvt(num, precision + 1, &decimal_point, is_negative);

    /*
     * Check for Infinity and NaN
     */
    if (xisalpha(*p)) {
	*len = strlen(strcpy(buf, p));
	*is_negative = FALSE;
	return (buf);
    }
    if (format == 'f') {
	if (decimal_point <= 0) {
	    *s++ = '0';
	    if (precision > 0) {
		*s++ = '.';
		while (decimal_point++ < 0)
		    *s++ = '0';
	    } else if (add_dp)
		*s++ = '.';
	} else {
	    while (decimal_point-- > 0)
		*s++ = *p++;
	    if (precision > 0 || add_dp)
		*s++ = '.';
	}
    } else {
	*s++ = *p++;
	if (precision > 0 || add_dp)
	    *s++ = '.';
    }

    /*
     * copy the rest of p, the NUL is NOT copied
     */
    while (*p)
	*s++ = *p++;

    if (format != 'f') {
	char temp[EXPONENT_LENGTH];	/* for exponent conversion */
	int t_len;
	bool_int exponent_is_negative;

	*s++ = format;		/* either e or E */
	decimal_point--;
	if (decimal_point != 0) {
	    p = conv_10((wide_int) decimal_point, FALSE, &exponent_is_negative,
		&temp[EXPONENT_LENGTH], &t_len);
	    *s++ = exponent_is_negative ? '-' : '+';

	    /*
	     * Make sure the exponent has at least 2 digits
	     */
	    if (t_len == 1)
		*s++ = '0';
	    while (t_len--)
		*s++ = *p++;