snprintf.c   [plain text]


/*	$NetBSD: snprintf.c,v 1.6 2007/07/22 05:19:02 lukem Exp $	*/

/*
 * 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
 *
 *  Luke Mewburn <lukem@NetBSD.org>, Thu Sep 30 23:28:21 EST 1999
 *	cleaned up formatting, autoconf tests
 *	added long long support
 *
 **************************************************************/

#include "tnftp.h"


#if defined(HAVE_LONG_DOUBLE)
#define LDOUBLE long double
#else
#define LDOUBLE double
#endif

#if defined(HAVE_LONG_LONG_INT)
#define LLONG long long
#else
#define LLONG long
#endif

static void dopr(char *buffer, size_t maxlen, size_t *retlen,
		    const char *format, va_list args);
static void fmtstr(char *buffer, size_t * currlen, size_t maxlen,
		    char *value, int min, int max, int flags);
static void fmtint(char *buffer, size_t * currlen, size_t maxlen,
		    LLONG 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, int 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')

static void
dopr(char *buffer, size_t maxlen, size_t *retlen, 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;
	flags = currlen = cflags = min = 0;
	max = -1;
	ch = *format++;

	while (state != DP_S_DONE) {
		if ((ch == '\0') || (currlen >= maxlen))
			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':
				if (*format == 'l') {
					cflags = DP_C_LLONG;
					format++;
				} else
					cflags = DP_C_LONG;
				ch = *format++;
				break;
			case 'q':
				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':
				switch (cflags) {
				case DP_C_SHORT:
					value = va_arg(args, int);
					break;
				case DP_C_LONG:
					value = va_arg(args, long int);
					break;
				case DP_C_LLONG:
					value = va_arg(args, LLONG);
					break;
				default:
					value = va_arg(args, int);
					break;
				}
				fmtint(buffer, &currlen, maxlen, value, 10,
				    min, max, flags);
				break;
			case 'X':
				flags |= DP_F_UP;
				/* FALLTHROUGH */
			case 'x':
			case 'o':
			case 'u':
				flags |= DP_F_UNSIGNED;
				switch (cflags) {
				case DP_C_SHORT:
					value = va_arg(args, unsigned int);
					break;
				case DP_C_LONG:
					value = (LLONG) va_arg(args,
					    unsigned long int);
					break;
				case DP_C_LLONG:
					value = va_arg(args, unsigned LLONG);
					break;
				default:
					value = (LLONG) va_arg(args,
					    unsigned int);
					break;
				}
				fmtint(buffer, &currlen, maxlen, value,
				    ch == 'o' ? 8 : (ch == 'u' ? 10 : 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 (max < 0)
					max = maxlen;	/* ie, no max */
				fmtstr(buffer, &currlen, maxlen, strvalue,
				    min, max, flags);
				break;
			case 'p':
				value = (long)va_arg(args, void *);
				fmtint(buffer, &currlen, maxlen,
				    value, 16, min, max, flags);
				break;
			case 'n':
/* XXX */
				if (cflags == DP_C_SHORT) {
					short int *num;
					num = va_arg(args, short int *);
					*num = currlen;
				} else if (cflags == DP_C_LONG) { /* XXX */
					long int *num;
					num = va_arg(args, long int *);
					*num = (long int) currlen;
				} else if (cflags == DP_C_LLONG) { /* XXX */
					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 (currlen >= maxlen - 1)
		currlen = maxlen - 1;
	buffer[currlen] = '\0';
	*retlen = currlen;
}

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

	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, LLONG value, int base,
	int min, int max, int flags)
{
	int		signvalue = 0;
	unsigned LLONG	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 long
round(LDOUBLE value)
{
	long	intpart;

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

	return intpart;
}

static void
fmtfp(char *buffer, size_t *currlen, size_t maxlen, LDOUBLE fvalue,
	int min, int max, int flags)
{
	int	signvalue = 0;
	LDOUBLE	ufvalue;
	char	iconvert[20];
	char	fconvert[20];
	int	iplace = 0;
	int	fplace = 0;
	int	padlen = 0;	/* amount to pad */
	int	zpadlen = 0;
	int	caps = 0;
	long	intpart;
	long	fracpart;

	/* 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

	intpart = (long) ufvalue;

	/* Sorry, we only support 9 digits past the decimal because of our
	 * conversion method */
	if (max > 9)
		max = 9;

	/* We "cheat" by converting the fractional part to integer by
	 * multiplying by a factor of 10 */
	fracpart = round((pow10(max)) * (ufvalue - intpart));

	if (fracpart >= pow10(max)) {
		intpart++;
		fracpart -= pow10(max);
	}
#ifdef DEBUG_SNPRINTF
	printf("fmtfp: %g %d.%d min=%d max=%d\n",
	    (double) fvalue, intpart, fracpart, min, max);
#endif

	/* Convert integer part */
	do {
		iconvert[iplace++] =
		    (caps ? "0123456789ABCDEF"
			  : "0123456789abcdef")[intpart % 10];
		intpart = (intpart / 10);
	} while (intpart && (iplace < 20));
	if (iplace == 20)
		iplace--;
	iconvert[iplace] = 0;

	/* Convert fractional part */
	do {
		fconvert[fplace++] =
		    (caps ? "0123456789ABCDEF"
			  : "0123456789abcdef")[fracpart % 10];
		fracpart = (fracpart / 10);
	} while (fracpart && (fplace < 20));
	if (fplace == 20)
		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, int c)
{
	if (*currlen < maxlen)
		buffer[(*currlen)++] = (char)c;
}

int
vsnprintf(char *str, size_t count, const char *fmt, va_list args)
{
	size_t retlen;

	str[0] = 0;
	dopr(str, count, &retlen, fmt, args);
	return (retlen);
}

/* VARARGS3 */
int
snprintf(char *str, size_t count, const char *fmt, ...)
{
	va_list	 ap;
	int	 rv;

	va_start(ap, fmt);
	rv = vsnprintf(str, count, fmt, ap);
	va_end(ap);
	return (rv);
}


#ifdef TEST_SNPRINTF
#ifndef LONG_STRING
#define LONG_STRING 1024
#endif

int
main(int argc, char *argv[])
{
	char	 buf1[LONG_STRING];
	char	 buf2[LONG_STRING];
	char	*fp_fmt[] = {
			"%-1.5f",
			"%1.5f",
			"%123.9f",
			"%10.5f",
			"% 10.5f",
			"%+22.9f",
			"%+4.9f",
			"%01.3f",
			"%4f",
			"%3.1f",
			"%3.2f",
			"%.0f",
			"%.1f",
			NULL
		 };
	double	 fp_nums[] = {
			-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",
#if defined(HAVE_LONG_LONG_INT)
			"%12lld",
#endif
			NULL
		 };
	LLONG	 int_nums[] = {
			-1, 134, 91340, 341, 0203,
			4294967290,
			4294967297,
			0
		 };
	int	 x, y;
	int	 fail = 0;
	int	 num = 0;
	int	 len;

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

	for (x = 0; fp_fmt[x] != NULL; x++) {
		printf("testing %s\n", fp_fmt[x]);
		for (y = 0; fp_nums[y] != 0; y++) {
			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",
				    fp_fmt[x]);
				printf("\tsnprintf = %s\n\tsprintf  = %s\n",
				    buf1, buf2);
				fail++;
			}
			num++;
		}
	}

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

	printf("%d tests failed out of %d.\n", fail, num);
	exit(0);
}
#endif /* TEST_SNPRINTF */