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subr_prf.c revision 1.11 
      1 /*	$NetBSD: subr_prf.c,v 1.11 2005/05/17 04:14:58 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  *
     31  *	@(#)printf.c	8.1 (Berkeley) 6/11/93
     32  */
     33 
     34 /*
     35  * Scaled down version of printf(3).
     36  */
     37 
     38 #include <sys/cdefs.h>
     39 #include <sys/types.h>
     40 #include <machine/stdarg.h>
     41 
     42 #include "stand.h"
     43 
     44 static void kprintn(void (*)(int), u_long, int);
     45 static void sputchar(int);
     46 static void kdoprnt(void (*)(int), const char *, va_list);
     47 
     48 static char *sbuf, *ebuf;
     49 
     50 const char hexdigits[] = "0123456789abcdef";
     51 
     52 static void
     53 sputchar(int c)
     54 {
     55 
     56 	if (sbuf < ebuf)
     57 		*sbuf++ = c;
     58 }
     59 
     60 void
     61 vprintf(const char *fmt, va_list ap)
     62 {
     63 
     64 	kdoprnt(putchar, fmt, ap);
     65 }
     66 
     67 int
     68 vsnprintf(char *buf, size_t size, const char *fmt, va_list ap)
     69 {
     70 
     71 	sbuf = buf;
     72 	ebuf = buf + size - 1;
     73 	kdoprnt(sputchar, fmt, ap);
     74 	*sbuf = '\0';
     75 	return (sbuf - buf);
     76 }
     77 
     78 static void
     79 kdoprnt(void (*put)(int), const char *fmt, va_list ap)
     80 {
     81 	char *p;
     82 	int ch;
     83 	unsigned long ul;
     84 	int lflag;
     85 
     86 	for (;;) {
     87 		while ((ch = *fmt++) != '%') {
     88 			if (ch == '\0')
     89 				return;
     90 			put(ch);
     91 		}
     92 		lflag = 0;
     93 reswitch:	switch (ch = *fmt++) {
     94 		case 'l':
     95 			lflag = 1;
     96 			goto reswitch;
     97 		case 'c':
     98 			ch = va_arg(ap, int);
     99 				put(ch & 0x7f);
    100 			break;
    101 		case 's':
    102 			p = va_arg(ap, char *);
    103 			while ((ch = *p++))
    104 				put(ch);
    105 			break;
    106 		case 'd':
    107 			ul = lflag ?
    108 			    va_arg(ap, long) : va_arg(ap, int);
    109 			if ((long)ul < 0) {
    110 				put('-');
    111 				ul = -(long)ul;
    112 			}
    113 			kprintn(put, ul, 10);
    114 			break;
    115 		case 'o':
    116 			ul = lflag ?
    117 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    118 			kprintn(put, ul, 8);
    119 			break;
    120 		case 'u':
    121 			ul = lflag ?
    122 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    123 			kprintn(put, ul, 10);
    124 			break;
    125 		case 'p':
    126 			put('0');
    127 			put('x');
    128 			lflag = 1;
    129 			/* fall through */
    130 		case 'x':
    131 			ul = lflag ?
    132 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    133 			kprintn(put, ul, 16);
    134 			break;
    135 		default:
    136 			put('%');
    137 			if (lflag)
    138 				put('l');
    139 			if (ch == '\0')
    140 				return;
    141 			put(ch);
    142 		}
    143 	}
    144 }
    145 
    146 static void
    147 kprintn(void (*put)(int), unsigned long ul, int base)
    148 {
    149 					/* hold a long in base 8 */
    150 	char *p, buf[(sizeof(long) * NBBY / 3) + 1];
    151 
    152 	p = buf;
    153 	do {
    154 		*p++ = hexdigits[ul % base];
    155 	} while (ul /= base);
    156 	do {
    157 		put(*--p);
    158 	} while (p > buf);
    159 }
    160