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subr_prf.c revision 1.16 
      1 /*	$NetBSD: subr_prf.c,v 1.16 2007/11/24 13:20:57 isaki 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 <sys/stdint.h>		/* XXX: for intptr_t */
     41 #include <machine/stdarg.h>
     42 
     43 #include "stand.h"
     44 
     45 static void kprintn(void (*)(int), u_long, int);
     46 static void sputchar(int);
     47 static void kdoprnt(void (*)(int), const char *, va_list);
     48 
     49 static char *sbuf, *ebuf;
     50 
     51 const char HEXDIGITS[] = "0123456789ABCDEF";
     52 const char hexdigits[] = "0123456789abcdef";
     53 
     54 static void
     55 sputchar(int c)
     56 {
     57 
     58 	if (sbuf < ebuf)
     59 		*sbuf++ = c;
     60 }
     61 
     62 void
     63 vprintf(const char *fmt, va_list ap)
     64 {
     65 
     66 	kdoprnt(putchar, fmt, ap);
     67 }
     68 
     69 int
     70 vsnprintf(char *buf, size_t size, const char *fmt, va_list ap)
     71 {
     72 
     73 	sbuf = buf;
     74 	ebuf = buf + size - 1;
     75 	kdoprnt(sputchar, fmt, ap);
     76 	*sbuf = '\0';
     77 	return sbuf - buf;
     78 }
     79 
     80 static void
     81 kdoprnt(void (*put)(int), const char *fmt, va_list ap)
     82 {
     83 	char *p;
     84 	int ch;
     85 	unsigned long ul;
     86 	int lflag;
     87 
     88 	for (;;) {
     89 		while ((ch = *fmt++) != '%') {
     90 			if (ch == '\0')
     91 				return;
     92 			put(ch);
     93 		}
     94 		lflag = 0;
     95 reswitch:
     96 		switch (ch = *fmt++) {
     97 		case 'l':
     98 			lflag = 1;
     99 			goto reswitch;
    100 		case 't':
    101 #if 0 /* XXX: abuse intptr_t until the situation with ptrdiff_t is clear */
    102 			lflag = (sizeof(ptrdiff_t) == sizeof(long));
    103 #else
    104 			lflag = (sizeof(intptr_t) == sizeof(long));
    105 #endif
    106 			goto reswitch;
    107 		case 'z':
    108 			lflag = (sizeof(size_t) == sizeof(unsigned long));
    109 			goto reswitch;
    110 		case 'c':
    111 			ch = va_arg(ap, int);
    112 				put(ch & 0x7f);
    113 			break;
    114 		case 's':
    115 			p = va_arg(ap, char *);
    116 			while ((ch = *p++))
    117 				put(ch);
    118 			break;
    119 		case 'd':
    120 			ul = lflag ?
    121 			    va_arg(ap, long) : va_arg(ap, int);
    122 			if ((long)ul < 0) {
    123 				put('-');
    124 				ul = -(long)ul;
    125 			}
    126 			kprintn(put, ul, 10);
    127 			break;
    128 		case 'o':
    129 			ul = lflag ?
    130 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    131 			kprintn(put, ul, 8);
    132 			break;
    133 		case 'u':
    134 			ul = lflag ?
    135 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    136 			kprintn(put, ul, 10);
    137 			break;
    138 		case 'p':
    139 			put('0');
    140 			put('x');
    141 			lflag = 1;
    142 			/* FALLTHROUGH */
    143 		case 'x':
    144 			ul = lflag ?
    145 			    va_arg(ap, u_long) : va_arg(ap, u_int);
    146 			kprintn(put, ul, 16);
    147 			break;
    148 		default:
    149 			put('%');
    150 			if (lflag)
    151 				put('l');
    152 			if (ch == '\0')
    153 				return;
    154 			put(ch);
    155 			break;
    156 		}
    157 	}
    158 }
    159 
    160 static void
    161 kprintn(void (*put)(int), unsigned long ul, int base)
    162 {
    163 					/* hold a long in base 8 */
    164 	char *p, buf[(sizeof(long) * NBBY / 3) + 1];
    165 
    166 	p = buf;
    167 	do {
    168 		*p++ = hexdigits[ul % base];
    169 	} while (ul /= base);
    170 	do {
    171 		put(*--p);
    172 	} while (p > buf);
    173 }
    174