PC Online 1999 April/PCO0499.ISO/filesbbs/os2/apach134.arj/APACH134.ZIP/src/ap/ap_snprintf.c

C/C++ Source or Header | 1999-01-01 | 23.7 KB | 1,026 lines

/* ====================================================================
 * Copyright (c) 1995-1999 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. For written permission, please contact
 *    [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * 6. 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 "httpd.h"

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

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

#ifndef FALSE
#define FALSE            0
#endif
#ifndef TRUE
#define TRUE            1
#endif
#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

/*
 * cvt.c - IEEE floating point formatting routines for FreeBSD
 * from GNU libc-4.6.27.  Modified to be thread safe.
 */

/*
 *    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

/* buf must have at least NDIG bytes */
static char *ap_cvt(double arg, int ndigits, int *decpt, int *sign, int eflag, char *buf)
{
    register int r2;
    double fi, fj;
    register char *p, *p1;

    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, char *buf)
{
    return (ap_cvt(arg, ndigits, decpt, sign, 1, buf));
}

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

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

static char *ap_gcvt(double number, int ndigit, char *buf, boolean_e altform)
{
    int sign, decpt;
    register char *p1, *p2;
    register int i;
    char buf1[NDIG];

    p1 = ap_ecvt(number, ndigit, &decpt, &sign, buf1);
    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] == '.' && !altform)
    p2--;
    *p2 = '\0';
    return (buf);
}

/*
 * 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) {                \
            vbuff->curpos = sp;                         \
            if (flush_func(vbuff))            \
            return -1;                \
            sp = vbuff->curpos;                \
            bep = vbuff->endpos;            \
        }                         \
        *sp++ = (c);                    \
        cc++;                         \
        }

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

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



static char *conv_in_addr(struct in_addr *ia, char *buf_end, int *len)
{
    unsigned addr = ntohl(ia->s_addr);
    char *p = buf_end;
    bool_int is_negative;
    int sub_len;

    p = conv_10((addr & 0x000000FF)      , TRUE, &is_negative, p, &sub_len);
    *--p = '.';
    p = conv_10((addr & 0x0000FF00) >>  8, TRUE, &is_negative, p, &sub_len);
    *--p = '.';
    p = conv_10((addr & 0x00FF0000) >> 16, TRUE, &is_negative, p, &sub_len);
    *--p = '.';
    p = conv_10((addr & 0xFF000000) >> 24, TRUE, &is_negative, p, &sub_len);

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



static char *conv_sockaddr_in(struct sockaddr_in *si, char *buf_end, int *len)
{
    char *p = buf_end;
    bool_int is_negative;
    int sub_len;

    p = conv_10(ntohs(si->sin_port), TRUE, &is_negative, p, &sub_len);
    *--p = ':';
    p = conv_in_addr(&si->sin_addr, p, &sub_len);

    *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;
    char buf1[NDIG];

    if (format == 'f')
    p = ap_fcvt(num, precision, &decimal_point, is_negative, buf1);
    else            /* either e or E format */
    p = ap_ecvt(num, precision + 1, &decimal_point, is_negative, buf1);

    /*
     * Check for Infinity and NaN
     */
    if (ap_isalpha(*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++;
    }
    else {
        *s++ = '+';
        *s++ = '0';
        *s++ = '0';
    }
    }

    *len = s - buf;
    return (buf);
}


/*
 * Convert num to a base X number where X is a power of 2. nbits determines X.
 * For example, if nbits is 3, we do base 8 conversion
 * Return value:
 *      a pointer to a string containing the number
 *
 * 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_p2(register u_wide_int num, register int nbits,
             char format, char *buf_end, register int *len)
{
    register int mask = (1 << nbits) - 1;
    register char *p = buf_end;
    static const char low_digits[] = "0123456789abcdef";
    static const char upper_digits[] = "0123456789ABCDEF";
    register const char *digits = (format == 'X') ? upper_digits : low_digits;

    do {
    *--p = digits[num & mask];
    num >>= nbits;
    }
    while (num);

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


/*
 * Do format conversion placing the output in buffer
 */
API_EXPORT(int) ap_vformatter(int (*flush_func)(ap_vformatter_buff *),
    ap_vformatter_buff *vbuff, const char *fmt, va_list ap)
{
    register char *sp;
    register char *bep;
    register int cc = 0;
    register int i;

    register char *s = NULL;
    char *q;
    int s_len;

    register int min_width = 0;
    int precision = 0;
    enum {
    LEFT, RIGHT
    } adjust;
    char pad_char;
    char prefix_char;

    double fp_num;
    wide_int i_num = (wide_int) 0;
    u_wide_int ui_num;

    char num_buf[NUM_BUF_SIZE];
    char char_buf[2];        /* for printing %% and %<unknown> */

    /*
     * Flag variables
     */
    boolean_e is_long;
    boolean_e alternate_form;
    boolean_e print_sign;
    boolean_e print_blank;
    boolean_e adjust_precision;
    boolean_e adjust_width;
    bool_int is_negative;

    sp = vbuff->curpos;
    bep = vbuff->endpos;

    while (*fmt) {
    if (*fmt != '%') {
        INS_CHAR(*fmt, sp, bep, cc);
    }
    else {
        /*
         * Default variable settings
         */
        adjust = RIGHT;
        alternate_form = print_sign = print_blank = NO;
        pad_char = ' ';
        prefix_char = NUL;

        fmt++;

        /*
         * Try to avoid checking for flags, width or precision
         */
        if (!ap_islower(*fmt)) {
        /*
         * Recognize flags: -, #, BLANK, +
         */
        for (;; fmt++) {
            if (*fmt == '-')
            adjust = LEFT;
            else if (*fmt == '+')
            print_sign = YES;
            else if (*fmt == '#')
            alternate_form = YES;
            else if (*fmt == ' ')
            print_blank = YES;
            else if (*fmt == '0')
            pad_char = '0';
            else
            break;
        }

        /*
         * Check if a width was specified
         */
        if (ap_isdigit(*fmt)) {
            STR_TO_DEC(fmt, min_width);
            adjust_width = YES;
        }
        else if (*fmt == '*') {
            min_width = va_arg(ap, int);
            fmt++;
            adjust_width = YES;
            if (min_width < 0) {
            adjust = LEFT;
            min_width = -min_width;
            }
        }
        else
            adjust_width = NO;

        /*
         * Check if a precision was specified
         *
         * XXX: an unreasonable amount of precision may be specified
         * resulting in overflow of num_buf. Currently we
         * ignore this possibility.
         */
        if (*fmt == '.') {
            adjust_precision = YES;
            fmt++;
            if (ap_isdigit(*fmt)) {
            STR_TO_DEC(fmt, precision);
            }
            else if (*fmt == '*') {
            precision = va_arg(ap, int);
            fmt++;
            if (precision < 0)
                precision = 0;
            }
            else
            precision = 0;
        }
        else
            adjust_precision = NO;
        }
        else
        adjust_precision = adjust_width = NO;

        /*
         * Modifier check
         */
        if (*fmt == 'l') {
        is_long = YES;
        fmt++;
        }
        else {
        if (*fmt == 'h')  /* "short" backward compatibility */
            ++fmt;
        is_long = NO;
        }

        /*
         * Argument extraction and printing.
         * First we determine the argument type.
         * Then, we convert the argument to a string.
         * On exit from the switch, s points to the string that
         * must be printed, s_len has the length of the string
         * The precision requirements, if any, are reflected in s_len.
         *
         * NOTE: pad_char may be set to '0' because of the 0 flag.
         *   It is reset to ' ' by non-numeric formats
         */
        switch (*fmt) {
        case 'u':
        if (is_long)
            i_num = va_arg(ap, u_wide_int);
        else
            i_num = (wide_int) va_arg(ap, unsigned int);
        s = conv_10(i_num, 1, &is_negative,
                &num_buf[NUM_BUF_SIZE], &s_len);
        FIX_PRECISION(adjust_precision, precision, s, s_len);
        break;

        case 'd':
        case 'i':
        if (is_long)
            i_num = va_arg(ap, wide_int);
        else
            i_num = (wide_int) va_arg(ap, int);
        s = conv_10(i_num, 0, &is_negative,
                &num_buf[NUM_BUF_SIZE], &s_len);
        FIX_PRECISION(adjust_precision, precision, s, s_len);

        if (is_negative)
            prefix_char = '-';
        else if (print_sign)
            prefix_char = '+';
        else if (print_blank)
            prefix_char = ' ';
        break;


        case 'o':
        if (is_long)
            ui_num = va_arg(ap, u_wide_int);
        else
            ui_num = (u_wide_int) va_arg(ap, unsigned int);
        s = conv_p2(ui_num, 3, *fmt,
                &num_buf[NUM_BUF_SIZE], &s_len);
        FIX_PRECISION(adjust_precision, precision, s, s_len);
        if (alternate_form && *s != '0') {
            *--s = '0';
            s_len++;
        }
        break;


        case 'x':
        case 'X':
        if (is_long)
            ui_num = (u_wide_int) va_arg(ap, u_wide_int);
        else
            ui_num = (u_wide_int) va_arg(ap, unsigned int);
        s = conv_p2(ui_num, 4, *fmt,
                &num_buf[NUM_BUF_SIZE], &s_len);
        FIX_PRECISION(adjust_precision, precision, s, s_len);
        if (alternate_form && i_num != 0) {
            *--s = *fmt;    /* 'x' or 'X' */
            *--s = '0';
            s_len += 2;
        }
        break;


        case 's':
        s = va_arg(ap, char *);
        if (s != NULL) {
            s_len = strlen(s);
            if (adjust_precision && precision < s_len)
            s_len = precision;
        }
        else {
            s = S_NULL;
            s_len = S_NULL_LEN;
        }
        pad_char = ' ';
        break;


        case 'f':
        case 'e':
        case 'E':
        fp_num = va_arg(ap, double);
        /*
         * * We use &num_buf[ 1 ], so that we have room for the sign
         */
        s = conv_fp(*fmt, fp_num, alternate_form,
            (adjust_precision == NO) ? FLOAT_DIGITS : precision,
                &is_negative, &num_buf[1], &s_len);
        if (is_negative)
            prefix_char = '-';
        else if (print_sign)
            prefix_char = '+';
        else if (print_blank)
            prefix_char = ' ';
        break;


        case 'g':
        case 'G':
        if (adjust_precision == NO)
            precision = FLOAT_DIGITS;
        else if (precision == 0)
            precision = 1;
        /*
         * * We use &num_buf[ 1 ], so that we have room for the sign
         */
        s = ap_gcvt(va_arg(ap, double), precision, &num_buf[1],
                    alternate_form);
        if (*s == '-')
            prefix_char = *s++;
        else if (print_sign)
            prefix_char = '+';
        else if (print_blank)
            prefix_char = ' ';

        s_len = strlen(s);

        if (alternate_form && (q = strchr(s, '.')) == NULL) {
            s[s_len++] = '.';
            s[s_len] = '\0'; /* delimit for following strchr() */
        }
        if (*fmt == 'G' && (q = strchr(s, 'e')) != NULL)
            *q = 'E';
        break;


        case 'c':
        char_buf[0] = (char) (va_arg(ap, int));
        s = &char_buf[0];
        s_len = 1;
        pad_char = ' ';
        break;


        case '%':
        char_buf[0] = '%';
        s = &char_buf[0];
        s_len = 1;
        pad_char = ' ';
        break;


        case 'n':
        *(va_arg(ap, int *)) = cc;
        break;

        /*
         * This is where we extend the printf format, with a second
         * type specifier
         */
        case 'p':
        switch(*++fmt) {
            /*
             * If the pointer size is equal to the size of an unsigned
             * integer we convert the pointer to a hex number, otherwise
             * we print "%p" to indicate that we don't handle "%p".
             */
        case 'p':
            ui_num = (u_wide_int) va_arg(ap, void *);

            if (sizeof(char *) <= sizeof(u_wide_int))
                s = conv_p2(ui_num, 4, 'x',
                        &num_buf[NUM_BUF_SIZE], &s_len);
            else {
            s = "%p";
            s_len = 2;
            prefix_char = NUL;
            }
            pad_char = ' ';
            break;

            /* print a struct sockaddr_in as a.b.c.d:port */
        case 'I':
            {
            struct sockaddr_in *si;

            si = va_arg(ap, struct sockaddr_in *);
            if (si != NULL) {
                s = conv_sockaddr_in(si, &num_buf[NUM_BUF_SIZE], &s_len);
                if (adjust_precision && precision < s_len)
                s_len = precision;
            }
            else {
                s = S_NULL;
                s_len = S_NULL_LEN;
            }
            pad_char = ' ';
            }
            break;

            /* print a struct in_addr as a.b.c.d */
        case 'A':
            {
            struct in_addr *ia;

            ia = va_arg(ap, struct in_addr *);
            if (ia != NULL) {
                s = conv_in_addr(ia, &num_buf[NUM_BUF_SIZE], &s_len);
                if (adjust_precision && precision < s_len)
                s_len = precision;
            }
            else {
                s = S_NULL;
                s_len = S_NULL_LEN;
            }
            pad_char = ' ';
            }
            break;

        case NUL:
            /* if %p ends the string, oh well ignore it */
            continue;

        default:
            s = "bogus %p";
            s_len = 8;
            prefix_char = NUL;
            break;
        }
        break;

        case NUL:
        /*
         * The last character of the format string was %.
         * We ignore it.
         */
        continue;


        /*
         * The default case is for unrecognized %'s.
         * We print %<char> to help the user identify what
         * option is not understood.
         * This is also useful in case the user wants to pass
         * the output of format_converter to another function
         * that understands some other %<char> (like syslog).
         * Note that we can't point s inside fmt because the
         * unknown <char> could be preceded by width etc.
         */
        default:
        char_buf[0] = '%';
        char_buf[1] = *fmt;
        s = char_buf;
        s_len = 2;
        pad_char = ' ';
        break;
        }

        if (prefix_char != NUL && s != S_NULL && s != char_buf) {
        *--s = prefix_char;
        s_len++;
        }

        if (adjust_width && adjust == RIGHT && min_width > s_len) {
        if (pad_char == '0' && prefix_char != NUL) {
            INS_CHAR(*s, sp, bep, cc);
            s++;
            s_len--;
            min_width--;
        }
        PAD(min_width, s_len, pad_char);
        }

        /*
         * Print the string s.
         */
        for (i = s_len; i != 0; i--) {
        INS_CHAR(*s, sp, bep, cc);
        s++;
        }

        if (adjust_width && adjust == LEFT && min_width > s_len)
        PAD(min_width, s_len, pad_char);
    }
    fmt++;
    }
    vbuff->curpos = sp;
    return cc;
}


static int snprintf_flush(ap_vformatter_buff *vbuff)
{
    /* if the buffer fills we have to abort immediately, there is no way
     * to "flush" an ap_snprintf... there's nowhere to flush it to.
     */
    return -1;
}


API_EXPORT(int) ap_snprintf(char *buf, size_t len, const char *format,...)
{
    int cc;
    va_list ap;
    ap_vformatter_buff vbuff;

    if (len == 0)
    return 0;

    /* save one byte for nul terminator */
    vbuff.curpos = buf;
    vbuff.endpos = buf + len - 1;
    va_start(ap, format);
    cc = ap_vformatter(snprintf_flush, &vbuff, format, ap);
    va_end(ap);
    *vbuff.curpos = '\0';
    return (cc == -1) ? len : cc;
}


API_EXPORT(int) ap_vsnprintf(char *buf, size_t len, const char *format,
                 va_list ap)
{
    int cc;
    ap_vformatter_buff vbuff;

    if (len == 0)
    return 0;

    /* save one byte for nul terminator */
    vbuff.curpos = buf;
    vbuff.endpos = buf + len - 1;
    cc = ap_vformatter(snprintf_flush, &vbuff, format, ap);
    *vbuff.curpos = '\0';
    return (cc == -1) ? len : cc;
}