aedrix-kernel/kernel/print.c

/*
    Copyright (C) 2012, Aaron Lindsay <aaron@aclindsay.com>

    This file is part of Aedrix.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <print.h>
#include <vargs.h>

/* This function exists solely so crashes don't happen if putc() gets
 * called before it is initialized. */
void putc_initial(char c) {
	(void)c;
}
void (*putc)(char) = &putc_initial;

void print_init(void (*putcfn)(char)) {
	if (putcfn)
		putc = putcfn;
}
 
void puts(const char *s)
{
    while (*s) putc (*s++);
}

void puti(int i)
{
	unsigned int left;
	char buf[1 << (sizeof(int)*8) / 10];
	char *p = buf;
	unsigned char negative = i < 0;

	if (!i)
		putc('0');

	left = negative ? -1*i : i;

	while (left) {
		unsigned int remainder = left % 10;
		left /= 10;
		*p = ('0'-0) + remainder;
		p++;
	}

	if (negative)
		putc('-');

	while (p-- != buf)
		putc(*p);
}

void putx(unsigned int i) {
	int j;

	puts("0x");

	for (j = 0; j < 8; j++) {
		unsigned int toprint = (i >> (4*(7-j))) & 0xf;
		if (toprint < 10)
			putc(('0'-0) + toprint);
		else
			putc(('a'-10) + toprint);
	}
}

void putb(unsigned int i) {
	int j;

	puts("0b");

	for (j = 0; j < 32; j++) {
		putc((i>>(31-j)) & 1 ? '1' : '0');
	}
}

int print(char *fmt, ...) {
	char *c;
	va_list arg;

	va_start(arg, fmt);
	for (c = fmt; *c; c++) {
		if (*c == '%') {
			switch (*++c) {
			case '%':
				putc('%');
				break;
			case 's':
				puts(va_arg(arg, char *));
				break;
			case 'c':
				putc(va_arg(arg, unsigned int));
				break;
			case 'd':
				puti(va_arg(arg, int));
				break;
			case 'x':
				putx(va_arg(arg, unsigned int));
				break;
			case 'b':
				putb(va_arg(arg, unsigned int));
				break;
			default:
				puts("\nError: print(): Invalid formatting character: '");
				putc(*c);
				puts("'\n");
				return -1;
			}
		} else {
			putc(*c);
		}
	}
	va_end(arg);

	return 0;
}