snprintf.c

/*
 * Copyright Patrick Powell 1995
 * This code is based on code written by Patrick Powell (papowell@astart.com)
 * It may be used for any purpose as long as this notice remains intact
 * on all source code distributions
 */

/**************************************************************
 * Original:
 * Patrick Powell Tue Apr 11 09:48:21 PDT 1995
 * A bombproof version of doprnt (dopr) included.
 * Sigh.  This sort of thing is always nasty do deal with.  Note that
 * the version here does not include floating point...
 *
 * snprintf() is used instead of sprintf() as it does limit checks
 * for string length.  This covers a nasty loophole.
 *
 * The other functions are there to prevent NULL pointers from
 * causing nast effects.
 *
 * More Recently:
 *  Brandon Long <blong@fiction.net> 9/15/96 for mutt 0.43
 *  This was ugly.  It is still ugly.  I opted out of floating point
 *  numbers, but the formatter understands just about everything
 *  from the normal C string format, at least as far as I can tell from
 *  the Solaris 2.5 printf(3S) man page.
 *
 *  Brandon Long <blong@fiction.net> 10/22/97 for mutt 0.87.1
 *    Ok, added some minimal floating point support, which means this
 *    probably requires libm on most operating systems.  Don't yet
 *    support the exponent (e,E) and sigfig (g,G).  Also, fmtint()
 *    was pretty badly broken, it just wasn't being exercised in ways
 *    which showed it, so that's been fixed.  Also, formated the code
 *    to mutt conventions, and removed dead code left over from the
 *    original.  Also, there is now a builtin-test, just compile with:
 *      gcc -DTEST_SNPRINTF -o snprintf snprintf.c -lm
 *    and run snprintf for results.
 *
 *  Thomas Roessler <roessler@guug.de> 01/27/98 for mutt 0.89i
 *    The PGP code was using unsigned hexadecimal formats.
 *    Unfortunately, unsigned formats simply didn't work.
 *
 *  Michael Elkins <me@cs.hmc.edu> 03/05/98 for mutt 0.90.8
 *    The original code assumed that both snprintf() and vsnprintf() were
 *    missing.  Some systems only have snprintf() but not vsnprintf(), so
 *    the code is now broken down under HAVE_SNPRINTF and HAVE_VSNPRINTF.
 *
 *  Andrew Tridgell (tridge@samba.org) Oct 1998
 *    fixed handling of %.0f
 *    added test for HAVE_LONG_DOUBLE
 *
 * tridge@samba.org, idra@samba.org, April 2001
 *    got rid of fcvt code (twas buggy and made testing harder)
 *    added C99 semantics
 *
 **************************************************************/

#ifndef NO_CONFIG_H /* for some tests */
#include "config.h"
#endif

#ifdef HAVE_STRING_H
#include <string.h>
#endif

#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#ifdef HAVE_CTYPE_H
#include <ctype.h>
#endif
#include <sys/types.h>
#include <stdarg.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#if defined(HAVE_SNPRINTF) && defined(HAVE_VSNPRINTF) && defined(HAVE_C99_VSNPRINTF)
/* only include stdio.h if we are not re-defining snprintf or vsnprintf */
#include <stdio.h>
 /* make the compiler happy with an empty file */
 void dummy_snprintf(void) {}
#else

#ifdef HAVE_LONG_DOUBLE
#define LDOUBLE long double
#else
#define LDOUBLE double
#endif

#ifdef HAVE_LONG_LONG
#define LLONG long long
#else
#define LLONG long
#endif

static size_t dopr(char *buffer, size_t maxlen, const char *format,
		   va_list args);
static void fmtstr(char *buffer, size_t *currlen, size_t maxlen,
		   char *value, int flags, int min, int max);
static void fmtint(char *buffer, size_t *currlen, size_t maxlen,
		   long value, int base, int min, int max, int flags);
static void fmtfp(char *buffer, size_t *currlen, size_t maxlen,
		  LDOUBLE fvalue, int min, int max, int flags);
static void dopr_outch(char *buffer, size_t *currlen, size_t maxlen, char c);

/*
 * dopr(): poor man's version of doprintf
 */

/* format read states */
#define DP_S_DEFAULT 0
#define DP_S_FLAGS   1
#define DP_S_MIN     2
#define DP_S_DOT     3
#define DP_S_MAX     4
#define DP_S_MOD     5
#define DP_S_CONV    6
#define DP_S_DONE    7

/* format flags - Bits */
#define DP_F_MINUS    (1 << 0)
#define DP_F_PLUS     (1 << 1)
#define DP_F_SPACE    (1 << 2)
#define DP_F_NUM      (1 << 3)
#define DP_F_ZERO     (1 << 4)
#define DP_F_UP       (1 << 5)
#define DP_F_UNSIGNED (1 << 6)

/* Conversion Flags */
#define DP_C_SHORT   1
#define DP_C_LONG    2
#define DP_C_LDOUBLE 3
#define DP_C_LLONG   4

#define char_to_int(p) ((p)- '0')
#ifndef MAX
#define MAX(p,q) (((p) >= (q)) ? (p) : (q))
#endif

static size_t dopr(char *buffer, size_t maxlen, const char *format, va_list args)
{
    char ch;
    LLONG value;
    LDOUBLE fvalue;
    char *strvalue;
    int min;
    int max;
    int state;
    int flags;
    int cflags;
    size_t currlen;

    state = DP_S_DEFAULT;
    currlen = flags = cflags = min = 0;
    max = -1;
    ch = *format++;

    while (state != DP_S_DONE) {
	if (ch == '\0')
	    state = DP_S_DONE;

	switch(state) {
	case DP_S_DEFAULT:
	    if (ch == '%')
		state = DP_S_FLAGS;
	    else
		dopr_outch (buffer, &currlen, maxlen, ch);
	    ch = *format++;
	    break;
	case DP_S_FLAGS:
	    switch (ch) {
	    case '-':
		flags |= DP_F_MINUS;
		ch = *format++;
		break;
	    case '+':
		flags |= DP_F_PLUS;
		ch = *format++;
		break;
	    case ' ':
		flags |= DP_F_SPACE;
		ch = *format++;
		break;
	    case '#':
		flags |= DP_F_NUM;
		ch = *format++;
		break;
	    case '0':
		flags |= DP_F_ZERO;
		ch = *format++;
		break;
	    default:
		state = DP_S_MIN;
		break;
	    }
	    break;
	case DP_S_MIN:
	    if (isdigit((unsigned char)ch)) {
		min = 10*min + char_to_int (ch);
		ch = *format++;
	    } else if (ch == '*') {
		min = va_arg (args, int);
		ch = *format++;
		state = DP_S_DOT;
	    } else {
		state = DP_S_DOT;
	    }
	    break;
	case DP_S_DOT:
	    if (ch == '.') {
		state = DP_S_MAX;
		ch = *format++;
	    } else {
		state = DP_S_MOD;
	    }
	    break;
	case DP_S_MAX:
	    if (isdigit((unsigned char)ch)) {
		if (max < 0)
		    max = 0;
		max = 10*max + char_to_int (ch);
		ch = *format++;
	    } else if (ch == '*') {
		max = va_arg (args, int);
		ch = *format++;
		state = DP_S_MOD;
	    } else {
		state = DP_S_MOD;
	    }
	    break;
	case DP_S_MOD:
	    switch (ch) {
	    case 'h':
		cflags = DP_C_SHORT;
		ch = *format++;
		break;
	    case 'l':
		cflags = DP_C_LONG;
		ch = *format++;
		if (ch == 'l') {    /* It's a long long */
		    cflags = DP_C_LLONG;
		    ch = *format++;
		}
		break;
	    case 'L':
		cflags = DP_C_LDOUBLE;
		ch = *format++;
		break;
	    default:
		break;
	    }
	    state = DP_S_CONV;
	    break;
	case DP_S_CONV:
	    switch (ch) {
	    case 'd':
	    case 'i':
		if (cflags == DP_C_SHORT)
		    value = va_arg (args, int);
		else if (cflags == DP_C_LONG)
		    value = va_arg (args, long int);
		else if (cflags == DP_C_LLONG)
		    value = va_arg (args, LLONG);
		else
		    value = va_arg (args, int);
		fmtint (buffer, &currlen, maxlen, value, 10, min, max, flags);
		break;
	    case 'o':
		flags |= DP_F_UNSIGNED;
		if (cflags == DP_C_SHORT)
		    value = va_arg (args, unsigned int);
		else if (cflags == DP_C_LONG)
		    value = (long)va_arg (args, unsigned long int);
		else if (cflags == DP_C_LLONG)
		    value = (long)va_arg (args, unsigned LLONG);
		else
		    value = (long)va_arg (args, unsigned int);
		fmtint (buffer, &currlen, maxlen, value, 8, min, max, flags);
		break;
	    case 'u':
		flags |= DP_F_UNSIGNED;
		if (cflags == DP_C_SHORT)
		    value = va_arg (args, unsigned int);
		else if (cflags == DP_C_LONG)
		    value = (long)va_arg (args, unsigned long int);
		else if (cflags == DP_C_LLONG)
		    value = (LLONG)va_arg (args, unsigned LLONG);
		else
		    value = (long)va_arg (args, unsigned int);
		fmtint (buffer, &currlen, maxlen, value, 10, min, max, flags);
		break;
	    case 'X':
		flags |= DP_F_UP;
	    case 'x':
		flags |= DP_F_UNSIGNED;
		if (cflags == DP_C_SHORT)
		    value = va_arg (args, unsigned int);
		else if (cflags == DP_C_LONG)
		    value = (long)va_arg (args, unsigned long int);
		else if (cflags == DP_C_LLONG)
		    value = (LLONG)va_arg (args, unsigned LLONG);
		else
		    value = (long)va_arg (args, unsigned int);
		fmtint (buffer, &currlen, maxlen, value, 16, min, max, flags);
		break;
	    case 'f':
		if (cflags == DP_C_LDOUBLE)
		    fvalue = va_arg (args, LDOUBLE);
		else
		    fvalue = va_arg (args, double);
		/* um, floating point? */
		fmtfp (buffer, &currlen, maxlen, fvalue, min, max, flags);
		break;
	    case 'E':
		flags |= DP_F_UP;
	    case 'e':
		if (cflags == DP_C_LDOUBLE)
		    fvalue = va_arg (args, LDOUBLE);
		else
		    fvalue = va_arg (args, double);
		break;
	    case 'G':
		flags |= DP_F_UP;
	    case 'g':
		if (cflags == DP_C_LDOUBLE)
		    fvalue = va_arg (args, LDOUBLE);
		else
		    fvalue = va_arg (args, double);
		break;
	    case 'c':
		dopr_outch (buffer, &currlen, maxlen, va_arg (args, int));
		break;
	    case 's':
		strvalue = va_arg (args, char *);
		if (!strvalue) strvalue = "(NULL)";
		if (max == -1) {
		    max = strlen(strvalue);
		}
		if (min > 0 && max >= 0 && min > max) max = min;
		fmtstr (buffer, &currlen, maxlen, strvalue, flags, min, max);
		break;
	    case 'p':
		strvalue = (char *)va_arg(args, void *);
		fmtint (buffer, &currlen, maxlen, (long) strvalue, 16, min, max, flags);
		break;
	    case 'n':
		if (cflags == DP_C_SHORT) {
		    short int *num;
		    num = va_arg (args, short int *);
		    *num = currlen;
		} else if (cflags == DP_C_LONG) {
		    long int *num;
		    num = va_arg (args, long int *);
		    *num = (long int)currlen;
		} else if (cflags == DP_C_LLONG) {
		    LLONG *num;
		    num = va_arg (args, LLONG *);
		    *num = (LLONG)currlen;
		} else {
		    int *num;
		    num = va_arg (args, int *);
		    *num = currlen;
		}
		break;
	    case '%':
		dopr_outch (buffer, &currlen, maxlen, ch);
		break;
	    case 'w':
		/* not supported yet, treat as next char */
		ch = *format++;
		break;
	    default:
		/* Unknown, skip */
		break;
	    }
	    ch = *format++;
	    state = DP_S_DEFAULT;
	    flags = cflags = min = 0;
	    max = -1;
	    break;
	case DP_S_DONE:
	    break;
	default:
	    /* hmm? */
	    break; /* some picky compilers need this */
	}
    }
    if (maxlen != 0) {
	if (currlen < maxlen - 1)
	    buffer[currlen] = '\0';
	else if (maxlen > 0)
	    buffer[maxlen - 1] = '\0';
    }

    return currlen;
}

static void fmtstr(char *buffer, size_t *currlen, size_t maxlen,
	     char *value, int flags, int min, int max)
{
    int padlen, strln;      /* amount to pad */
    int cnt = 0;

#ifdef DEBUG_SNPRINTF
    printf("fmtstr min=%d max=%d s=[%s]\n", min, max, value);
#endif
    if (value == 0) {
	value = "<NULL>";
    }

    for (strln = 0; value[strln]; ++strln); /* strlen */
    padlen = min - strln;
    if (padlen < 0)
	padlen = 0;
    if (flags & DP_F_MINUS)
	padlen = -padlen; /* Left Justify */

    while ((padlen > 0) && (cnt < max)) {
	dopr_outch (buffer, currlen, maxlen, ' ');
	--padlen;
	++cnt;
    }
    while (*value && (cnt < max)) {
	dopr_outch (buffer, currlen, maxlen, *value++);
	++cnt;
    }
    while ((padlen < 0) && (cnt < max)) {
	dopr_outch (buffer, currlen, maxlen, ' ');
	++padlen;
	++cnt;
    }
}

/* Have to handle DP_F_NUM (ie 0x and 0 alternates) */

static void fmtint(char *buffer, size_t *currlen, size_t maxlen,
	     long value, int base, int min, int max, int flags)
{
    int signvalue = 0;
    unsigned long uvalue;
    char convert[20];
    int place = 0;
    int spadlen = 0; /* amount to space pad */
    int zpadlen = 0; /* amount to zero pad */
    int caps = 0;

    if (max < 0)
	max = 0;

    uvalue = value;

    if(!(flags & DP_F_UNSIGNED)) {
	if( value < 0 ) {
	    signvalue = '-';
	    uvalue = -value;
	} else {
	    if (flags & DP_F_PLUS)  /* Do a sign (+/i) */
		signvalue = '+';
	    else if (flags & DP_F_SPACE)
		signvalue = ' ';
	}
    }

    if (flags & DP_F_UP) caps = 1; /* Should characters be upper case? */

    do {
	convert[place++] =
	    (caps? "0123456789ABCDEF":"0123456789abcdef")
	    [uvalue % (unsigned)base  ];
	uvalue = (uvalue / (unsigned)base );
    } while(uvalue && (place < 20));
    if (place == 20) place--;
    convert[place] = 0;

    zpadlen = max - place;
    spadlen = min - MAX (max, place) - (signvalue ? 1 : 0);
    if (zpadlen < 0) zpadlen = 0;
    if (spadlen < 0) spadlen = 0;
    if (flags & DP_F_ZERO) {
	zpadlen = MAX(zpadlen, spadlen);
	spadlen = 0;
    }
    if (flags & DP_F_MINUS)
	spadlen = -spadlen; /* Left Justifty */

#ifdef DEBUG_SNPRINTF
    printf("zpad: %d, spad: %d, min: %d, max: %d, place: %d\n",
	     zpadlen, spadlen, min, max, place);
#endif

    /* Spaces */
    while (spadlen > 0) {
	dopr_outch (buffer, currlen, maxlen, ' ');
	--spadlen;
    }

    /* Sign */
    if (signvalue)
	dopr_outch (buffer, currlen, maxlen, signvalue);

    /* Zeros */
    if (zpadlen > 0) {
	while (zpadlen > 0) {
	    dopr_outch (buffer, currlen, maxlen, '0');
	    --zpadlen;
	}
    }

    /* Digits */
    while (place > 0)
	dopr_outch (buffer, currlen, maxlen, convert[--place]);

    /* Left Justified spaces */
    while (spadlen < 0) {
	dopr_outch (buffer, currlen, maxlen, ' ');
	++spadlen;
    }
}

static LDOUBLE abs_val(LDOUBLE value)
{
    LDOUBLE result = value;

    if (value < 0)
	result = -value;

    return result;
}

static LDOUBLE POW10(int exp)
{
    LDOUBLE result = 1;

    while (exp) {
	result *= 10;
	exp--;
    }

    return result;
}

static LLONG ROUND(LDOUBLE value)
{
    LLONG intpart;

    intpart = (LLONG)value;
    value = value - intpart;
    if (value >= 0.5) intpart++;

    return intpart;
}

/* a replacement for modf that doesn't need the math library. Should
    be portable, but slow */
static double my_modf(double x0, double *iptr)
{
    int i;
    long l;
    double x = x0;
    double f = 1.0;

    for (i=0;i<100;i++) {
	l = (long)x;
	if (l <= (x+1) && l >= (x-1)) break;
	x *= 0.1;
	f *= 10.0;
    }

    if (i == 100) {
	/* yikes! the number is beyond what we can handle. What do we do? */
	(*iptr) = 0;
	return 0;
    }

    if (i != 0) {
	double i2;
	double ret;

	ret = my_modf(x0-l*f, &i2);
	(*iptr) = l*f + i2;
	return ret;
    }

    (*iptr) = l;
    return x - (*iptr);
}

static void fmtfp (char *buffer, size_t *currlen, size_t maxlen,
	    LDOUBLE fvalue, int min, int max, int flags)
{
    int signvalue = 0;
    double ufvalue;
    char iconvert[311];
    char fconvert[311];
    int iplace = 0;
    int fplace = 0;
    int padlen = 0; /* amount to pad */
    int zpadlen = 0;
    int caps = 0;
    int index;
    double intpart;
    double fracpart;
    double temp;

    /*
     * AIX manpage says the default is 0, but Solaris says the default
     * is 6, and sprintf on AIX defaults to 6
     */
    if (max < 0)
	max = 6;

    ufvalue = abs_val (fvalue);

    if (fvalue < 0) {
	signvalue = '-';
    } else {
	if (flags & DP_F_PLUS) { /* Do a sign (+/i) */
	    signvalue = '+';
	} else {
	    if (flags & DP_F_SPACE)
		signvalue = ' ';
	}
    }

#if 0
    if (flags & DP_F_UP) caps = 1; /* Should characters be upper case? */
#endif

#if 0
     if (max == 0) ufvalue += 0.5; /* if max = 0 we must round */
#endif

    /*
     * Sorry, we only support 16 digits past the decimal because of our
     * conversion method
     */
    if (max > 16)
	max = 16;

    /* We "cheat" by converting the fractional part to integer by
     * multiplying by a factor of 10
     */

    temp = ufvalue;
    my_modf(temp, &intpart);

    fracpart = ROUND((POW10(max)) * (ufvalue - intpart));

    if (fracpart >= POW10(max)) {
	intpart++;
	fracpart -= POW10(max);
    }


    /* Convert integer part */
    do {
	temp = intpart;
	my_modf(intpart*0.1, &intpart);
	temp = temp*0.1;
	index = (int) ((temp -intpart +0.05)* 10.0);
	/* index = (int) (((double)(temp*0.1) -intpart +0.05) *10.0); */
	/* printf ("%llf, %f, %x\n", temp, intpart, index); */
	iconvert[iplace++] =
	    (caps? "0123456789ABCDEF":"0123456789abcdef")[index];
    } while (intpart && (iplace < 311));
    if (iplace == 311) iplace--;
    iconvert[iplace] = 0;

    /* Convert fractional part */
    if (fracpart)
    {
	do {
	    temp = fracpart;
	    my_modf(fracpart*0.1, &fracpart);
	    temp = temp*0.1;
	    index = (int) ((temp -fracpart +0.05)* 10.0);
	    /* index = (int) ((((temp/10) -fracpart) +0.05) *10); */
	    /* printf ("%lf, %lf, %ld\n", temp, fracpart, index); */
	    fconvert[fplace++] =
	    (caps? "0123456789ABCDEF":"0123456789abcdef")[index];
	} while(fracpart && (fplace < 311));
	if (fplace == 311) fplace--;
    }
    fconvert[fplace] = 0;

    /* -1 for decimal point, another -1 if we are printing a sign */
    padlen = min - iplace - max - 1 - ((signvalue) ? 1 : 0);
    zpadlen = max - fplace;
    if (zpadlen < 0) zpadlen = 0;
    if (padlen < 0)
	padlen = 0;
    if (flags & DP_F_MINUS)
	padlen = -padlen; /* Left Justifty */

    if ((flags & DP_F_ZERO) && (padlen > 0)) {
	if (signvalue) {
	    dopr_outch (buffer, currlen, maxlen, signvalue);
	    --padlen;
	    signvalue = 0;
	}
	while (padlen > 0) {
	    dopr_outch (buffer, currlen, maxlen, '0');
	    --padlen;
	}
    }
    while (padlen > 0) {
	dopr_outch (buffer, currlen, maxlen, ' ');
	--padlen;
    }
    if (signvalue)
	dopr_outch (buffer, currlen, maxlen, signvalue);

    while (iplace > 0)
	dopr_outch (buffer, currlen, maxlen, iconvert[--iplace]);

#ifdef DEBUG_SNPRINTF
    printf("fmtfp: fplace=%d zpadlen=%d\n", fplace, zpadlen);
#endif

    /*
     * Decimal point.  This should probably use locale to find the correct
     * char to print out.
     */
    if (max > 0) {
	dopr_outch (buffer, currlen, maxlen, '.');
	
	while (fplace > 0)
	    dopr_outch (buffer, currlen, maxlen, fconvert[--fplace]);
    }

    while (zpadlen > 0) {
	dopr_outch (buffer, currlen, maxlen, '0');
	--zpadlen;
    }

    while (padlen < 0) {
	dopr_outch (buffer, currlen, maxlen, ' ');
	++padlen;
    }
}

static void dopr_outch(char *buffer, size_t *currlen, size_t maxlen, char c)
{
    if (*currlen < maxlen) {
	buffer[(*currlen)] = c;
    }
    (*currlen)++;
}

/* yes this really must be a ||. Don't muck with this (tridge) */
#if !defined(HAVE_VSNPRINTF) || !defined(HAVE_C99_VSNPRINTF)
 int vsnprintf (char *str, size_t count, const char *fmt, va_list args)
{
    return dopr(str, count, fmt, args);
}
#endif

/* yes this really must be a ||. Don't muck wiith this (tridge)
 *
 * The logic for these two is that we need our own definition if the
 * OS *either* has no definition of *sprintf, or if it does have one
 * that doesn't work properly according to the autoconf test.  Perhaps
 * these should really be smb_snprintf to avoid conflicts with buggy
 * linkers? -- mbp
 */
#if !defined(HAVE_SNPRINTF) || !defined(HAVE_C99_SNPRINTF)
 int snprintf(char *str,size_t count,const char *fmt,...)
{
    size_t ret;
    va_list ap;

    va_start(ap, fmt);
    ret = vsnprintf(str, count, fmt, ap);
    va_end(ap);
    return ret;
}
#endif

#endif

#ifndef HAVE_VASPRINTF
 int vasprintf(char **ptr, const char *format, va_list ap)
{
    int ret;

    ret = vsnprintf(0, 0, format, ap);
    if (ret <= 0) return ret;

    (*ptr) = (char *)malloc(ret+1);
    if (!*ptr) return -1;
    ret = vsnprintf(*ptr, ret+1, format, ap);

    return ret;
}
#endif


#ifndef HAVE_ASPRINTF
 int asprintf(char **ptr, const char *format, ...)
{
    va_list ap;
    int ret;

    *ptr = 0;
    va_start(ap, format);
    ret = vasprintf(ptr, format, ap);
    va_end(ap);

    return ret;
}
#endif

#ifndef HAVE_VSYSLOG
#ifdef HAVE_SYSLOG
 void vsyslog (int facility_priority, char *format, va_list arglist)
{
    char *msg = 0;
    vasprintf(&msg, format, arglist);
    if (!msg)
	return;
    syslog(facility_priority, "%s", msg);
    free(msg);
}
#endif /* HAVE_SYSLOG */
#endif /* HAVE_VSYSLOG */

#ifdef TEST_SNPRINTF

 int sprintf(char *str,const char *fmt,...);

 int main (void)
{
    char buf1[1024];
    char buf2[1024];
    char *fp_fmt[] = {
	"%1.1f",
	"%-1.5f",
	"%1.5f",
	"%123.9f",
	"%10.5f",
	"% 10.5f",
	"%+22.9f",
	"%+4.9f",
	"%01.3f",
	"%4f",
	"%3.1f",
	"%3.2f",
	"%.0f",
	"%f",
	"-16.16f",
	0
    };
    double fp_nums[] = { 6442452944.1234, -1.5, 134.21, 91340.2, 341.1234, 0203.9, 0.96, 0.996,
		  0.9996, 1.996, 4.136,  0};
    char *int_fmt[] = {
	"%-1.5d",
	"%1.5d",
	"%123.9d",
	"%5.5d",
	"%10.5d",
	"% 10.5d",
	"%+22.33d",
	"%01.3d",
	"%4d",
	"%d",
	0
    };
    long int_nums[] = { -1, 134, 91340, 341, 0203, 0};
    char *str_fmt[] = {
	"10.5s",
	"5.10s",
	"10.1s",
	"0.10s",
	"10.0s",
	"1.10s",
	"%s",
	"%.1s",
	"%.10s",
	"%10s",
	0
    };
    char *str_vals[] = {"hello", "a", "", "a longer string", 0};
    int x, y;
    int fail = 0;
    int num = 0;

    printf ("Testing snprintf format codes against system sprintf...\n");

    for (x = 0; fp_fmt[x] ; x++) {
	for (y = 0; fp_nums[y] != 0 ; y++) {
	    int l1 = snprintf(0, 0, fp_fmt[x], fp_nums[y]);
	    int l2 = snprintf(buf1, sizeof(buf1), fp_fmt[x], fp_nums[y]);
	    sprintf (buf2, fp_fmt[x], fp_nums[y]);
	    if (strcmp (buf1, buf2)) {
		printf("snprintf doesn't match Format: %s\n\tsnprintf = [%s]\n\t sprintf = [%s]\n",
			 fp_fmt[x], buf1, buf2);
		fail++;
	    }
	    if (l1 != l2) {
		printf("snprintf l1 != l2 (%d %d) %s\n", l1, l2, fp_fmt[x]);
		fail++;
	    }
	    num++;
	}
    }

    for (x = 0; int_fmt[x] ; x++) {
	for (y = 0; int_nums[y] != 0 ; y++) {
	    int l1 = snprintf(0, 0, int_fmt[x], int_nums[y]);
	    int l2 = snprintf(buf1, sizeof(buf1), int_fmt[x], int_nums[y]);
	    sprintf (buf2, int_fmt[x], int_nums[y]);
	    if (strcmp (buf1, buf2)) {
		printf("snprintf doesn't match Format: %s\n\tsnprintf = [%s]\n\t sprintf = [%s]\n",
			 int_fmt[x], buf1, buf2);
		fail++;
	    }
	    if (l1 != l2) {
		printf("snprintf l1 != l2 (%d %d) %s\n", l1, l2, int_fmt[x]);
		fail++;
	    }
	    num++;
	}
    }

    for (x = 0; str_fmt[x] ; x++) {
	for (y = 0; str_vals[y] != 0 ; y++) {
	    int l1 = snprintf(0, 0, str_fmt[x], str_vals[y]);
	    int l2 = snprintf(buf1, sizeof(buf1), str_fmt[x], str_vals[y]);
	    sprintf (buf2, str_fmt[x], str_vals[y]);
	    if (strcmp (buf1, buf2)) {
		printf("snprintf doesn't match Format: %s\n\tsnprintf = [%s]\n\t sprintf = [%s]\n",
			 str_fmt[x], buf1, buf2);
		fail++;
	    }
	    if (l1 != l2) {
		printf("snprintf l1 != l2 (%d %d) %s\n", l1, l2, str_fmt[x]);
		fail++;
	    }
	    num++;
	}
    }

    printf ("%d tests failed out of %d.\n", fail, num);

    printf("seeing how many digits we support\n");
    {
	double v0 = 0.12345678901234567890123456789012345678901;
	for (x=0; x<100; x++) {
	    snprintf(buf1, sizeof(buf1), "%1.1f", v0*pow(10, x));
	    sprintf(buf2,	"%1.1f", v0*pow(10, x));
	    if (strcmp(buf1, buf2)) {
		printf("we seem to support %d digits\n", x-1);
		break;
	    }
	}
    }

    return 0;
}
#endif /* SNPRINTF_TEST */