OrionLibC

diff --git a/stdio/vsprintf.c b/stdio/vsprintf.c
new file mode 100644
index 0000000..88e2f9f
--- /dev/null
+++ b/stdio/vsprintf.c
@@ -0,0 +1,244 @@
+#include <stdarg.h>
+#include <string.h>
+
+#define is_digit(c)	((c) >= '0' && (c) <= '9')
+
+/* Do not convert */
+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) ({ \
+int __res; \
+__asm__("divl %4":"=a" (n),"=d" (__res):"0" (n),"1" (0),"r" (base)); \
+__res; })
+
+/* Convert a number to ASCII */
+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;
+}
+
+/* Print formatted to a buffer */
+int
+vsprintf(char *buf, const char *fmt, va_list args)
+{
+	int len, i;
+	char *str, *s;
+	int *ip, flags;
+	int field_width, precision, qualifier;
+
+	for (str = buf; *fmt; fmt++) {
+		if (*fmt != '%') {
+			*str++ = *fmt;
+			continue;
+		}
+
+		/* Process flags */
+		flags = 0;
+repeat:
+		fmt++;
+		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 == '*') {
+			field_width = va_arg(args, int);
+			fmt++;
+			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 == '*') {
+				precision = va_arg(args, int);
+				fmt++;
+			}
+			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;
+			/* FALLTHROUGH */
+		case 'X':
+			str = number(str, va_arg(args, unsigned long), 16,
+				field_width, precision, flags);
+			break;
+
+		case 'd': /* FALLTHROUGH */
+		case 'i':
+			flags |= SIGN;
+			/* FALLTHROUGH */
+		case 'u':
+			str = number(str, va_arg(args, unsigned long), 10,
+				field_width, precision, flags);
+			break;
+
+		case 'f':
+			str = number(str,
+				(unsigned long) va_arg(args, double), 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;
+}