/*	$NetBSD: subr_prf.c,v 1.16 2007/11/24 13:20:57 isaki Exp $	*/

/*-
 * Copyright (c) 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * 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. 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.
 *
 *	@(#)printf.c	8.1 (Berkeley) 6/11/93
 */

/*
 * Scaled down version of printf(3).
 */

#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/stdint.h>		/* XXX: for intptr_t */
#include <machine/stdarg.h>

#include "stand.h"

static void kprintn(void (*)(int), u_long, int);
static void sputchar(int);
static void kdoprnt(void (*)(int), const char *, va_list);

static char *sbuf, *ebuf;

const char HEXDIGITS[] = "0123456789ABCDEF";
const char hexdigits[] = "0123456789abcdef";

static void
sputchar(int c)
{

	if (sbuf < ebuf)
		*sbuf++ = c;
}

void
vprintf(const char *fmt, va_list ap)
{

	kdoprnt(putchar, fmt, ap);
}

int
vsnprintf(char *buf, size_t size, const char *fmt, va_list ap)
{

	sbuf = buf;
	ebuf = buf + size - 1;
	kdoprnt(sputchar, fmt, ap);
	*sbuf = '\0';
	return sbuf - buf;
}

static void
kdoprnt(void (*put)(int), const char *fmt, va_list ap)
{
	char *p;
	int ch;
	unsigned long ul;
	int lflag;

	for (;;) {
		while ((ch = *fmt++) != '%') {
			if (ch == '\0')
				return;
			put(ch);
		}
		lflag = 0;
reswitch:
		switch (ch = *fmt++) {
		case 'l':
			lflag = 1;
			goto reswitch;
		case 't':
#if 0 /* XXX: abuse intptr_t until the situation with ptrdiff_t is clear */
			lflag = (sizeof(ptrdiff_t) == sizeof(long));
#else
			lflag = (sizeof(intptr_t) == sizeof(long));
#endif
			goto reswitch;
		case 'z':
			lflag = (sizeof(size_t) == sizeof(unsigned long));
			goto reswitch;
		case 'c':
			ch = va_arg(ap, int);
				put(ch & 0x7f);
			break;
		case 's':
			p = va_arg(ap, char *);
			while ((ch = *p++))
				put(ch);
			break;
		case 'd':
			ul = lflag ?
			    va_arg(ap, long) : va_arg(ap, int);
			if ((long)ul < 0) {
				put('-');
				ul = -(long)ul;
			}
			kprintn(put, ul, 10);
			break;
		case 'o':
			ul = lflag ?
			    va_arg(ap, u_long) : va_arg(ap, u_int);
			kprintn(put, ul, 8);
			break;
		case 'u':
			ul = lflag ?
			    va_arg(ap, u_long) : va_arg(ap, u_int);
			kprintn(put, ul, 10);
			break;
		case 'p':
			put('0');
			put('x');
			lflag = 1;
			/* FALLTHROUGH */
		case 'x':
			ul = lflag ?
			    va_arg(ap, u_long) : va_arg(ap, u_int);
			kprintn(put, ul, 16);
			break;
		default:
			put('%');
			if (lflag)
				put('l');
			if (ch == '\0')
				return;
			put(ch);
			break;
		}
	}
}

static void
kprintn(void (*put)(int), unsigned long ul, int base)
{
					/* hold a long in base 8 */
	char *p, buf[(sizeof(long) * NBBY / 3) + 1];

	p = buf;
	do {
		*p++ = hexdigits[ul % base];
	} while (ul /= base);
	do {
		put(*--p);
	} while (p > buf);
}