We're not using the .Bu macro anymore.

[nmh] / sbr / snprintf.c

/*
 * snprintf.c -- formatted output to a string
 *
 * This is an implementation of snprintf() and vsnprintf()
 * taken from the Apache web server.  This is only used on
 * systems which do not have a native version.
 */

/* ====================================================================
 * 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
 *    apache@apache.org.
 *
 * 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
 * <panos@alumni.cs.colorado.edu> for xinetd.
 */

#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <netinet/in.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 struct {
    char *curpos;
    char *endpos;
} ap_vformatter_buff;

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

/* These macros allow correct support of 8-bit characters on systems which
 * support 8-bit characters.  Pretty dumb how the cast is required, but
 * that's legacy libc for ya.  These new macros do not support EOF like
 * the standard macros do.  Tough.
 */
#define ap_isalpha(c) (isalpha(((unsigned char)(c))))
#define ap_isdigit(c) (isdigit(((unsigned char)(c))))
#define ap_islower(c) (islower(((unsigned char)(c))))

/*
 * 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
 */
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" a snprintf... there's nowhere to flush it to.
     */
    return -1;
}


int 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;
}


int 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;
}