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subr_prf.c revision 1.12 
      1 /*	$NetBSD: subr_prf.c,v 1.12 2005/05/23 19:05:00 jmc 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 const char hexdigits[] = "0123456789abcdef";
     52 
     53 static void
     54 sputchar(int c)
     55 {
     56 
     57 	if (sbuf < ebuf)
     58 		*sbuf++ = c;
     59 }
     60 
     61 void
     62 vprintf(const char *fmt, va_list ap)
     63 {
     64 
     65 	kdoprnt(putchar, fmt, ap);
     66 }
     67 
     68 int
     69 vsnprintf(char *buf, size_t size, const char *fmt, va_list ap)
     70 {
     71 
     72 	sbuf = buf;
     73 	ebuf = buf + size - 1;
     74 	kdoprnt(sputchar, fmt, ap);
     75 	*sbuf = '\0';
     76 	return (sbuf - buf);
     77 }
     78 
     79 static void
     80 kdoprnt(void (*put)(int), const char *fmt, va_list ap)
     81 {
     82 	char *p;
     83 	int ch;
     84 	unsigned long ul;
     85 	int lflag;
     86 
     87 	for (;;) {
     88 		while ((ch = *fmt++) != '%') {
     89 			if (ch == '\0')
     90 				return;
     91 			put(ch);
     92 		}
     93 		lflag = 0;
     94 reswitch:	switch (ch = *fmt++) {
     95 		case 'l':
     96 			lflag = 1;
     97 			goto reswitch;
     98 		case 'c':
     99 			ch = va_arg(ap, int);
    100 				put(ch & 0x7f);
    101 			break;
    102 		case 's':
    103 			p = va_arg(ap, char *);
    104 			while ((ch = *p++))
    105 				put(ch);
    106 			break;
    107 		case 'd':
    108 			ul = lflag ?
    109 			    va_arg(ap, long) : va_arg(ap, int);
    110 			if ((long)ul < 0) {
    111 				put('-');
    112 				ul = -(long)ul;
    113 			}
    114 			kprintn(put, ul, 10);
    115 			break;
    116 		case 'o':
    117 			ul = lflag ?
    118 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    119 			kprintn(put, ul, 8);
    120 			break;
    121 		case 'u':
    122 			ul = lflag ?
    123 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    124 			kprintn(put, ul, 10);
    125 			break;
    126 		case 'p':
    127 			put('0');
    128 			put('x');
    129 			lflag = 1;
    130 			/* fall through */
    131 		case 'x':
    132 			ul = lflag ?
    133 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    134 			kprintn(put, ul, 16);
    135 			break;
    136 		default:
    137 			put('%');
    138 			if (lflag)
    139 				put('l');
    140 			if (ch == '\0')
    141 				return;
    142 			put(ch);
    143 		}
    144 	}
    145 }
    146 
    147 static void
    148 kprintn(void (*put)(int), unsigned long ul, int base)
    149 {
    150 					/* hold a long in base 8 */
    151 	char *p, buf[(sizeof(long) * NBBY / 3) + 1];
    152 
    153 	p = buf;
    154 	do {
    155 		*p++ = hexdigits[ul % base];
    156 	} while (ul /= base);
    157 	do {
    158 		put(*--p);
    159 	} while (p > buf);
    160 }
    161