vsprintf.c

msLinux v1.0 可以在arm ads 下仿真运行的linux

/* MShowTec - www.mshowtec.com
** msLinux vsprintf.c ver1.0
** 20051221 lmjx create [e-mail]
**
*/

#define MSLINUX_VSPRINTF_C

#include "stdarg.h"
#include "string.h"

#define is_digit(c) ((c) >= '0' && (c) <= '9')

static int skip_atoi (const char **s)
{
	int i = 0;

	while (is_digit (**s))
		i = i * 10 + *((*s)++) - '0';
	return i;
}

#define ZEROPAD 1 /* pad with zero */
#define SIGN 2 /* unsigned/signed long */
#define PLUS 4 /* show plus */
#define SPACE 8 /* space if plus */
#define LEFT 16 /* left justified */
#define SPECIAL 32 /* 0x */
#define SMALL 64 /* use 'abcdef' instead of 'ABCDEF' */

#define do_div(n,base) _do_div(&(n),base)
__inline int _do_div(int *n,int base)
{
	int mod;
	
	mod = (*n)%base;
	*n = (*n)/base;
	
	return mod;
}

static char *number (char *str, int num, int base, int size, int precision, int type)
{
	char c, sign, tmp[36];
	const char *digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	int i;

	if (type & SMALL)
		digits = "0123456789abcdefghijklmnopqrstuvwxyz";
	if (type & LEFT)
		type &= ~ZEROPAD;
	if (base < 2 || base > 36)
		return 0;
	c = (type & ZEROPAD) ? '0' : ' ';
	if (type & SIGN && num < 0)
	{
		sign = '-';
		num = -num;
	}
	else
		sign = (type & PLUS) ? '+' : ((type & SPACE) ? ' ' : 0);
	if (sign)
		size--;
	if (type & SPECIAL)
		if (base == 16)
			size -= 2;
		else if (base == 8)
			size--;
	i = 0;
	if (num == 0)
		tmp[i++] = '0';
	else
		while (num != 0)
			tmp[i++] = digits[do_div (num, base)];
	if (i > precision)
		precision = i;
	size -= precision;
	if (!(type & (ZEROPAD + LEFT)))
		while (size-- > 0)
			*str++ = ' ';
	if (sign)
		*str++ = sign;
	if (type & SPECIAL)
		if (base == 8)
			*str++ = '0';
		else if (base == 16)
		{
			*str++ = '0';
			*str++ = digits[33];
		}
	if (!(type & LEFT))
		while (size-- > 0)
			*str++ = c;
	while (i < precision--)
		*str++ = '0';
	while (i-- > 0)
		*str++ = tmp[i];
	while (size-- > 0)
		*str++ = ' ';
	return str;
}

int vsprintf (char *buf, const char *fmt, va_list args)
{
	int len;
	int i;
	char *str;
	char *s;
	int *ip;

	int flags;			/* flags to number() */
	int field_width;		/* width of output field */
	int precision;		/* min. # of digits for integers; max
				   number of chars for from string */
	int qualifier;		/* 'h', 'l', or 'L' for integer fields */
	
	for (str = buf; *fmt; ++fmt)
	{
		if (*fmt != '%')
		{
			*str++ = *fmt;
			continue;
		}

		flags = 0;
repeat:
		++fmt;			/* this also skips first '%' */
		switch (*fmt)
		{
		case '-':
			flags |= LEFT;
			goto repeat;
		case '+':
			flags |= PLUS;
			goto repeat;
		case ' ':
			flags |= SPACE;
			goto repeat;
		case '#':
			flags |= SPECIAL;
			goto repeat;
		case '0':
			flags |= ZEROPAD;
			goto repeat;
		}

/* get field width */
		field_width = -1;
		if (is_digit (*fmt))
			field_width = skip_atoi (&fmt);
		else if (*fmt == '*')
		{
/* it's the next argument */
			field_width = va_arg (args, int);
			if (field_width < 0)
			{
				field_width = -field_width;
				flags |= LEFT;
			}
		}

/* get the precision */
		precision = -1;
		if (*fmt == '.')
		{
			++fmt;
			if (is_digit (*fmt))
				precision = skip_atoi (&fmt);
			else if (*fmt == '*')
			{
/* it's the next argument */
				precision = va_arg (args, int);
			}
			if (precision < 0)
			precision = 0;
		}

/* get the conversion qualifier */
		qualifier = -1;
		if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L')
		{
			qualifier = *fmt;
			++fmt;
		}
		switch (*fmt)
		{
		case 'c':
			if (!(flags & LEFT))
				while (--field_width > 0)
					*str++ = ' ';
			*str++ = (unsigned char) va_arg (args, int);
			while (--field_width > 0)
				*str++ = ' ';
			break;

		case 's':
			s = va_arg (args, char *);
			len = strlen (s);
			if (precision < 0)
				precision = len;
			else if (len > precision)
				len = precision;

			if (!(flags & LEFT))
				while (len < field_width--)
					*str++ = ' ';
			for (i = 0; i < len; ++i)
				*str++ = *s++;
			while (len < field_width--)
				*str++ = ' ';
			break;

		case 'o':
			str = number (str, va_arg (args, unsigned long), 8,
									field_width, precision, flags);
			break;

		case 'p':
			if (field_width == -1)
			{
				field_width = 8;
				flags |= ZEROPAD;
			}
			str = number (str, (unsigned long) va_arg (args, void *), 16,
							field_width, precision, flags);
			break;

		case 'x':
			flags |= SMALL;
		case 'X':
			str = number (str, va_arg (args, unsigned long), 16,
									field_width, precision, flags);
			break;

		case 'd':
		case 'i':
			flags |= SIGN;
		case 'u':
			str = number (str, va_arg (args, unsigned long), 10,
									field_width, precision, flags);
			break;
		case 'n':
			ip = va_arg (args, int *);
			*ip = (str - buf);
			break;
		default:
			if (*fmt != '%')
				*str++ = '%';
			if (*fmt)
				*str++ = *fmt;
			else
				--fmt;
			break;
		}
	}
	*str = '\0';
	return str - buf;
} 

int sprintf(char * buf, const char *fmt, ...)
{
	va_list args;
	int i;

	var_start(args, fmt);
	i=vsprintf(buf,fmt,args);
	va_end(args);
	return i;
}