subr_scanf.c

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/*-
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id: subr_scanf.c,v 1.1.2.1 1999/01/29 06:39:23 dillon Exp $
 * From: Id: vfscanf.c,v 1.13 1998/09/25 12:20:27 obrien Exp 
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <machine/limits.h>

/*
 * Note that stdarg.h and the ANSI style va_start macro is used for both
 * ANSI and traditional C compilers.
 */
#include <machine/stdarg.h>

#define	BUF		32 	/* Maximum length of numeric string. */

/*
 * Flags used during conversion.
 */
#define	LONG		0x01	/* l: long or double */
#define	SHORT		0x04	/* h: short */
#define	SUPPRESS	0x08	/* suppress assignment */
#define	POINTER		0x10	/* weird %p pointer (`fake hex') */
#define	NOSKIP		0x20	/* do not skip blanks */
#define	QUAD		0x400

/*
 * The following are used in numeric conversions only:
 * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
 * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
 */
#define	SIGNOK		0x40	/* +/- is (still) legal */
#define	NDIGITS		0x80	/* no digits detected */

#define	DPTOK		0x100	/* (float) decimal point is still legal */
#define	EXPOK		0x200	/* (float) exponent (e+3, etc) still legal */

#define	PFXOK		0x100	/* 0x prefix is (still) legal */
#define	NZDIGITS	0x200	/* no zero digits detected */

/*
 * Conversion types.
 */
#define	CT_CHAR		0	/* %c conversion */
#define	CT_CCL		1	/* %[...] conversion */
#define	CT_STRING	2	/* %s conversion */
#define	CT_INT		3	/* integer, i.e., strtoq or strtouq */
typedef u_quad_t (*ccfntype)(const char *, char **, int);

#define isspace(c)	((c) == ' ' || (c) == '\t' || \
			 (c) == '\r' || (c) == '\n')
#define isascii(c)	(((c) & ~0x7f) == 0)
#define isupper(c)	((c) >= 'A' && (c) <= 'Z')
#define islower(c)	((c) >= 'a' && (c) <= 'z')
#define isalpha(c)	(isupper(c) || (islower(c)))
#define isdigit(c)	((c) >= '0' && (c) <= '9')

static u_char *__sccl(char *, u_char *);

int
sscanf(const char *ibuf, const char *fmt, ...)
{
	va_list ap;
	int ret;
	
	va_start(ap, fmt);
	ret = vsscanf(ibuf, fmt, ap);
	va_end(ap);
	return(ret);
}

int
vsscanf(const char *inp, char const *fmt0, va_list ap)
{
	int inr;
	u_char *fmt = (u_char *)fmt0;
	int c;			/* character from format, or conversion */
	size_t width;		/* field width, or 0 */
	char *p;		/* points into all kinds of strings */
	int n;			/* handy integer */
	int flags;		/* flags as defined above */
	char *p0;		/* saves original value of p when necessary */
	int nassigned;		/* number of fields assigned */
	int nconversions;	/* number of conversions */
	int nread;		/* number of characters consumed from fp */
	int base;		/* base argument to strtoq/strtouq */
	ccfntype ccfn;		/* conversion function (strtoq/strtouq) */
	char ccltab[256];	/* character class table for %[...] */
	char buf[BUF];		/* buffer for numeric conversions */

	/* `basefix' is used to avoid `if' tests in the integer scanner */
	static short basefix[17] =
		{ 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };

	inr = strlen(inp);
	
	nassigned = 0;
	nconversions = 0;
	nread = 0;
	base = 0;		/* XXX just to keep gcc happy */
	ccfn = NULL;		/* XXX just to keep gcc happy */
	for (;;) {
		c = *fmt++;
		if (c == 0)
			return (nassigned);
		if (isspace(c)) {
			while (inr > 0 && isspace(*inp))
				nread++, inr--, inp++;
			continue;
		}
		if (c != '%')
			goto literal;
		width = 0;
		flags = 0;
		/*
		 * switch on the format.  continue if done;
		 * break once format type is derived.
		 */
again:		c = *fmt++;
		switch (c) {
		case '%':
literal:
			if (inr <= 0)
				goto input_failure;
			if (*inp != c)
				goto match_failure;
			inr--, inp++;
			nread++;
			continue;

		case '*':
			flags |= SUPPRESS;
			goto again;
		case 'l':
			flags |= LONG;
			goto again;
		case 'q':
			flags |= QUAD;
			goto again;
		case 'h':
			flags |= SHORT;
			goto again;

		case '0': case '1': case '2': case '3': case '4':
		case '5': case '6': case '7': case '8': case '9':
			width = width * 10 + c - '0';
			goto again;

		/*
		 * Conversions.
		 *
		 */
		case 'd':
			c = CT_INT;
			ccfn = (ccfntype)strtoq;
			base = 10;
			break;

		case 'i':
			c = CT_INT;
			ccfn = (ccfntype)strtoq;
			base = 0;
			break;

		case 'o':
			c = CT_INT;
			ccfn = strtouq;
			base = 8;
			break;

		case 'u':
			c = CT_INT;
			ccfn = strtouq;
			base = 10;
			break;

		case 'x':
			flags |= PFXOK;	/* enable 0x prefixing */
			c = CT_INT;
			ccfn = strtouq;
			base = 16;
			break;

		case 's':
			c = CT_STRING;
			break;

		case '[':
			fmt = __sccl(ccltab, fmt);
			flags |= NOSKIP;
			c = CT_CCL;
			break;

		case 'c':
			flags |= NOSKIP;
			c = CT_CHAR;
			break;

		case 'p':	/* pointer format is like hex */
			flags |= POINTER | PFXOK;
			c = CT_INT;
			ccfn = strtouq;
			base = 16;
			break;

		case 'n':
			nconversions++;
			if (flags & SUPPRESS)	/* ??? */
				continue;
			if (flags & SHORT)
				*va_arg(ap, short *) = nread;
			else if (flags & LONG)
				*va_arg(ap, long *) = nread;
			else if (flags & QUAD)
				*va_arg(ap, quad_t *) = nread;
			else
				*va_arg(ap, int *) = nread;
			continue;
		}

		/*
		 * We have a conversion that requires input.
		 */
		if (inr <= 0)
			goto input_failure;

		/*
		 * Consume leading white space, except for formats
		 * that suppress this.
		 */
		if ((flags & NOSKIP) == 0) {
			while (isspace(*inp)) {
				nread++;
				if (--inr > 0)
					inp++;
				else 
					goto input_failure;
			}
			/*
			 * Note that there is at least one character in
			 * the buffer, so conversions that do not set NOSKIP
			 * can no longer result in an input failure.
			 */
		}

		/*
		 * Do the conversion.
		 */
		switch (c) {

		case CT_CHAR:
			/* scan arbitrary characters (sets NOSKIP) */
			if (width == 0)
				width = 1;
			if (flags & SUPPRESS) {
				size_t sum = 0;
				for (;;) {
					if ((n = inr) < width) {
						sum += n;
						width -= n;
						inp += n;
						if (sum == 0)
							goto input_failure;
							break;
					} else {
						sum += width;
						inr -= width;
						inp += width;
						break;
					}
				}
				nread += sum;
			} else {
				bcopy(inp, va_arg(ap, char *), width);
				inr -= width;
				inp += width;
				nread += width;
				nassigned++;
			}
			nconversions++;
			break;

		case CT_CCL:
			/* scan a (nonempty) character class (sets NOSKIP) */
			if (width == 0)
				width = (size_t)~0;	/* `infinity' */
			/* take only those things in the class */
			if (flags & SUPPRESS) {
				n = 0;
				while (ccltab[(unsigned char)*inp]) {
					n++, inr--, inp++;
					if (--width == 0)
						break;
					if (inr <= 0) {
						if (n == 0)
							goto input_failure;
						break;
					}
				}
				if (n == 0)
					goto match_failure;
			} else {
				p0 = p = va_arg(ap, char *);
				while (ccltab[(unsigned char)*inp]) {
					inr--;
					*p++ = *inp++;
					if (--width == 0)
						break;
					if (inr <= 0) {
						if (p == p0)
							goto input_failure;
						break;
					}
				}
				n = p - p0;
				if (n == 0)
					goto match_failure;
				*p = 0;
				nassigned++;
			}
			nread += n;
			nconversions++;
			break;

		case CT_STRING:
			/* like CCL, but zero-length string OK, & no NOSKIP */
			if (width == 0)
				width = (size_t)~0;
			if (flags & SUPPRESS) {
				n = 0;
				while (!isspace(*inp)) {
					n++, inr--, inp++;
					if (--width == 0)
						break;
					if (inr <= 0)
						break;
				}
				nread += n;
			} else {
				p0 = p = va_arg(ap, char *);
				while (!isspace(*inp)) {
					inr--;
					*p++ = *inp++;
					if (--width == 0)
						break;
					if (inr <= 0)
						break;
				}
				*p = 0;
				nread += p - p0;
				nassigned++;
			}
			nconversions++;
			continue;

		case CT_INT:
			/* scan an integer as if by strtoq/strtouq */
#ifdef hardway
			if (width == 0 || width > sizeof(buf) - 1)
				width = sizeof(buf) - 1;
#else