snprintf.c

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	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 */
	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
my_abs(LDOUBLE value)
{
	LDOUBLE result = value;

	if (value < 0)
		result = -value;

	return result;
}

static LDOUBLE
my_pow10(int exp)
{
	LDOUBLE result = 1;

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

	return result;
}

static LLONG
my_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];
	char *numbers = (char *) &hexnumbers;
	int iplace = 0;
	int fplace = 0;
	int padlen = 0; /* amount to pad */
	int zpadlen = 0;
	int index;
	double intpart;
	double fracpart;
	double temp;
	LDOUBLE pow;

	/*
	 * 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 = my_abs(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? */
		numbers = (char *) &HEXnumbers;
	}
#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;

	pow = my_pow10(max);

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

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

	fracpart = my_round(pow * (ufvalue - intpart));

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

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

	/* Convert fractional part */
	if (fracpart) {
		do {
			temp = fracpart * 0.1;
			my_modf(temp, &fracpart);
			index = (int) ((temp - fracpart + 0.05) * 10.0);
#if 0
			index = (int) ((((temp/10) -fracpart) +0.05) *10);
			printf ("%lf, %lf, %ld\n", temp, fracpart, index);
#endif
			fconvert[fplace++] = numbers[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 (zpadlen > 0) {
			dopr_outch(buffer, currlen, maxlen, '0');
			--zpadlen;
		}

		while (fplace > 0)
			dopr_outch(buffer, currlen, maxlen, fconvert[--fplace]);
	}

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


/* Yes the following preprocessor conditions really must be a ||. Don't muck
 * with this. -- tridge
 *
 * The logic for these 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. -- mbp */

#if !defined(HAVE_VSNPRINTF) || !defined(HAVE_C99_VSNPRINTF)
int
elinks_vsnprintf(char *str, size_t count, const char *fmt, va_list args)
{
	return dopr(str, count, fmt, args);
}
#endif

#if !defined(HAVE_SNPRINTF) || !defined(HAVE_C99_VSNPRINTF)
int
elinks_snprintf(char *str, size_t count, const char *fmt, ...)
{
	size_t ret;
	va_list ap;

	va_start(ap, fmt);
	/* snprintf.h makes this to expand to the right thing. */
	ret = vsnprintf(str, count, fmt, ap);
	va_end(ap);

	return ret;
}
#endif

#endif /* defined(HAVE_SNPRINTF) && defined(HAVE_VSNPRINTF) && defined(HAVE_C99_VSNPRINTF) */


#ifndef HAVE_VASPRINTF
int
elinks_vasprintf(char **ptr, const char *format, va_list ap)
{
	int ret;
	va_list ap2;

	VA_COPY(ap2, ap);

	ret = vsnprintf(NULL, 0, format, ap2);
	if (ret <= 0) return ret;

	/* Should we use mem_alloc() here instead of malloc() ??? --Zas */
	/* No: This is an alternative to the system vasprintf.
	 * When the system provides vasprintf, it will use malloc(),
	 * which means that the string will need to be freed with free().
	 * If we did use mem_alloc here in our alternative to the system
	 * vasprintf, we would need to change all users of the memory
	 * allocated by vasprintf to take into account whether the system
	 * vasprintf (and therefore malloc) or our own vasprintf
	 * (and therefore mem_alloc) were used. -- Miciah */
	(*ptr) = (char *) malloc(ret + 1);
	if (!*ptr) return -1;

	VA_COPY(ap2, ap);

	return vsnprintf(*ptr, ret + 1, format, ap2);
}
#endif


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

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

	return ret;
}
#endif

unsigned char *
asprintfa(const char *fmt, ...)
{
	unsigned char *str;
	va_list ap;

	va_start(ap, fmt);
	str = vasprintfa(fmt, ap);
	va_end(ap);

	return str;
}

/* Test program */
#ifdef TEST_SNPRINTF

#include <math.h>

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",
		NULL
	};
	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, 5.030201, 0};
	char *int_fmt[] = {
		"%-1.5d",
		"%1.5d",
		"%123.9d",
		"%5.5d",
		"%10.5d",
		"% 10.5d",
		"%+22.33d",
		"%01.3d",
		"%4d",
		"%d",
		NULL
	};
	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",
		NULL
	};
	char *str_vals[] = {"hello", "a", "", "a longer string", NULL};
	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(NULL, 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\t"
				       "snprintf = [%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(NULL, 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\t"
				       "snprintf = [%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(NULL, 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\t"
				       "snprintf = [%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++) {
			double p = pow(10, x);
			double r = v0*p;

			snprintf(buf1, sizeof(buf1), "%1.1f", r);
			sprintf(buf2,"%1.1f", r);
			if (strcmp(buf1, buf2)) {
				printf("we seem to support %d digits\n", x-1);
				break;
			}
		}
	}

	return 0;
}
#endif /* SNPRINTF_TEST */