kern/src/vsprintf.c

/*
 *  linux/lib/vsprintf.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
/*
 * Wirzenius wrote this portably, Torvalds fucked it up :-)
 */

/*
 * Fri Jul 13 2001 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
 * - changed to provide snprintf and vsnprintf functions
 * So Feb  1 16:51:32 CET 2004 Juergen Quade <quade@hsnr.de>
 * - scnprintf and vscnprintf
 */

/* (trimmed to just scanf for Akaros).  grep AKAROS_PORT for dirty hacks */

#include <ros/common.h>
#include <error.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <ns.h>
#include <ctype.h>

/**
 * skip_spaces - Removes leading whitespace from @str.
 * @str: The string to be stripped.
 *
 * Returns a pointer to the first non-whitespace character in @str.
 */
static char *skip_spaces(const char *str)
{
	while (isspace(*str))
		++str;
	return (char *)str;
}

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

	while (isdigit(**s))
		i = i*10 + *((*s)++) - '0';

	return i;
}

const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
{
	if (*base == 0) {
		if (s[0] == '0') {
			if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
				*base = 16;
			else
				*base = 8;
		} else
			*base = 10;
	}
	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
		s += 2;
	return s;
}

/**
 * vsscanf - Unformat a buffer into a list of arguments
 * @buf:	input buffer
 * @fmt:	format of buffer
 * @args:	arguments
 */
int vsscanf(const char *buf, const char *fmt, va_list args)
{
	const char *str = buf;
	char *next;
	char digit;
	int num = 0;
	uint8_t qualifier;
	unsigned int base;
	union {
		long long s;
		unsigned long long u;
	} val;
	int16_t field_width;
	bool is_sign;

	while (*fmt) {
		/* skip any white space in format */
		/* white space in format matchs any amount of
		 * white space, including none, in the input.
		 */
		if (isspace(*fmt)) {
			fmt = skip_spaces(++fmt);
			str = skip_spaces(str);
		}

		/* anything that is not a conversion must match exactly */
		if (*fmt != '%' && *fmt) {
			if (*fmt++ != *str++)
				break;
			continue;
		}

		if (!*fmt)
			break;
		++fmt;

		/* skip this conversion.
		 * advance both strings to next white space
		 */
		if (*fmt == '*') {
			if (!*str)
				break;
			while (!isspace(*fmt) && *fmt != '%' && *fmt)
				fmt++;
			while (!isspace(*str) && *str)
				str++;
			continue;
		}

		/* get field width */
		field_width = -1;
		if (isdigit(*fmt)) {
			field_width = skip_atoi(&fmt);
			if (field_width <= 0)
				break;
		}

		/* get conversion qualifier */
		qualifier = -1;
		if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
		    _tolower(*fmt) == 'z') {
			qualifier = *fmt++;
			if (unlikely(qualifier == *fmt)) {
				if (qualifier == 'h') {
					qualifier = 'H';
					fmt++;
				} else if (qualifier == 'l') {
					qualifier = 'L';
					fmt++;
				}
			}
		}

		if (!*fmt)
			break;

		if (*fmt == 'n') {
			/* return number of characters read so far */
			*va_arg(args, int *) = str - buf;
			++fmt;
			continue;
		}

		if (!*str)
			break;

		base = 10;
		is_sign = false;

		switch (*fmt++) {
		case 'c':
		{
			char *s = (char *)va_arg(args, char*);
			if (field_width == -1)
				field_width = 1;
			do {
				*s++ = *str++;
			} while (--field_width > 0 && *str);
			num++;
		}
		continue;
		case 's':
		{
			char *s = (char *)va_arg(args, char *);
			if (field_width == -1)
				field_width = INT16_MAX;
			/* first, skip leading white space in buffer */
			str = skip_spaces(str);

			/* now copy until next white space */
			while (*str && !isspace(*str) && field_width--)
				*s++ = *str++;
			*s = '\0';
			num++;
		}
		continue;
		case 'o':
			base = 8;
			break;
		case 'x':
		case 'X':
			base = 16;
			break;
		case 'i':
			base = 0;
		case 'd':
			is_sign = true;
		case 'u':
			break;
		case '%':
			/* looking for '%' in str */
			if (*str++ != '%')
				return num;
			continue;
		default:
			/* invalid format; stop here */
			return num;
		}

		/* have some sort of integer conversion.
		 * first, skip white space in buffer.
		 */
		str = skip_spaces(str);

		digit = *str;
		if (is_sign && digit == '-')
			digit = *(str + 1);

		if (!digit
		    || (base == 16 && !isxdigit(digit))
		    || (base == 10 && !isdigit(digit))
		    || (base == 8 && (!isdigit(digit) || digit > '7'))
		    || (base == 0 && !isdigit(digit)))
			break;

		if (is_sign)
#if 0 // AKAROS_PORT
			val.s = qualifier != 'L' ?
				strtol(str, &next, base) :
				strtoll(str, &next, base);
#else
			val.s = strtol(str, &next, base);
#endif
		else
#if 0 // AKAROS_PORT
			val.u = qualifier != 'L' ?
				strtoul(str, &next, base) :
				strtoull(str, &next, base);
#else
			val.s = strtoul(str, &next, base);
#endif

		if (field_width > 0 && next - str > field_width) {
			if (base == 0)
				_parse_integer_fixup_radix(str, &base);
			while (next - str > field_width) {
				if (is_sign)	// AKAROS_PORT
					val.s = (int64_t)(val.s / base);
				else
					val.u = (uint64_t)(val.u / base);
				--next;
			}
		}

		switch (qualifier) {
		case 'H':	/* that's 'hh' in format */
			if (is_sign)
				*va_arg(args, signed char *) = val.s;
			else
				*va_arg(args, unsigned char *) = val.u;
			break;
		case 'h':
			if (is_sign)
				*va_arg(args, short *) = val.s;
			else
				*va_arg(args, unsigned short *) = val.u;
			break;
		case 'l':
			if (is_sign)
				*va_arg(args, long *) = val.s;
			else
				*va_arg(args, unsigned long *) = val.u;
			break;
		case 'L':
			if (is_sign)
				*va_arg(args, long long *) = val.s;
			else
				*va_arg(args, unsigned long long *) = val.u;
			break;
		case 'Z':
		case 'z':
			*va_arg(args, size_t *) = val.u;
			break;
		default:
			if (is_sign)
				*va_arg(args, int *) = val.s;
			else
				*va_arg(args, unsigned int *) = val.u;
			break;
		}
		num++;

		if (!next)
			break;
		str = next;
	}

	return num;
}

/**
 * sscanf - Unformat a buffer into a list of arguments
 * @buf:	input buffer
 * @fmt:	formatting of buffer
 * @...:	resulting arguments
 */
int sscanf(const char *buf, const char *fmt, ...)
{
	va_list args;
	int i;

	va_start(args, fmt);
	i = vsscanf(buf, fmt, args);
	va_end(args);

	return i;
}