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subr_prf.c revision 1.10 
      1 /*	$NetBSD: subr_prf.c,v 1.10 2003/08/07 16:32:30 agc 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 static void
     51 sputchar(int c)
     52 {
     53 
     54 	if (sbuf < ebuf)
     55 		*sbuf++ = c;
     56 }
     57 
     58 void
     59 vprintf(const char *fmt, va_list ap)
     60 {
     61 
     62 	kdoprnt(putchar, fmt, ap);
     63 }
     64 
     65 int
     66 vsnprintf(char *buf, size_t size, const char *fmt, va_list ap)
     67 {
     68 
     69 	sbuf = buf;
     70 	ebuf = buf + size - 1;
     71 	kdoprnt(sputchar, fmt, ap);
     72 	*sbuf = '\0';
     73 	return (sbuf - buf);
     74 }
     75 
     76 static void
     77 kdoprnt(void (*put)(int), const char *fmt, va_list ap)
     78 {
     79 	char *p;
     80 	int ch;
     81 	unsigned long ul;
     82 	int lflag;
     83 
     84 	for (;;) {
     85 		while ((ch = *fmt++) != '%') {
     86 			if (ch == '\0')
     87 				return;
     88 			put(ch);
     89 		}
     90 		lflag = 0;
     91 reswitch:	switch (ch = *fmt++) {
     92 		case 'l':
     93 			lflag = 1;
     94 			goto reswitch;
     95 		case 'c':
     96 			ch = va_arg(ap, int);
     97 				put(ch & 0x7f);
     98 			break;
     99 		case 's':
    100 			p = va_arg(ap, char *);
    101 			while ((ch = *p++))
    102 				put(ch);
    103 			break;
    104 		case 'd':
    105 			ul = lflag ?
    106 			    va_arg(ap, long) : va_arg(ap, int);
    107 			if ((long)ul < 0) {
    108 				put('-');
    109 				ul = -(long)ul;
    110 			}
    111 			kprintn(put, ul, 10);
    112 			break;
    113 		case 'o':
    114 			ul = lflag ?
    115 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    116 			kprintn(put, ul, 8);
    117 			break;
    118 		case 'u':
    119 			ul = lflag ?
    120 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    121 			kprintn(put, ul, 10);
    122 			break;
    123 		case 'p':
    124 			put('0');
    125 			put('x');
    126 			lflag = 1;
    127 			/* fall through */
    128 		case 'x':
    129 			ul = lflag ?
    130 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    131 			kprintn(put, ul, 16);
    132 			break;
    133 		default:
    134 			put('%');
    135 			if (lflag)
    136 				put('l');
    137 			if (ch == '\0')
    138 				return;
    139 			put(ch);
    140 		}
    141 	}
    142 }
    143 
    144 static void
    145 kprintn(void (*put)(int), unsigned long ul, int base)
    146 {
    147 					/* hold a long in base 8 */
    148 	char *p, buf[(sizeof(long) * NBBY / 3) + 1];
    149 
    150 	p = buf;
    151 	do {
    152 		*p++ = "0123456789abcdef"[ul % base];
    153 	} while (ul /= base);
    154 	do {
    155 		put(*--p);
    156 	} while (p > buf);
    157 }
    158