minix/lib/syslib/kprintf.c
2005-04-21 14:53:53 +00:00

189 lines
3.5 KiB
C
Executable file

/* printf() - kernel printf() Author: Kees J. Bot
* 15 Jan 1994
*/
#define nil 0
#include <stdarg.h>
#include <stddef.h>
#include <limits.h>
#define isdigit(c) ((unsigned) ((c) - '0') < (unsigned) 10)
#if !__STDC__
/* Classic C stuff, ignore. */
void kputc();
int printf(fmt) char *fmt;
#else
/* Printf() uses kputc() to print characters. */
void kputc(int c);
int printf(const char *fmt, ...)
#endif
{
int c;
enum { LEFT, RIGHT } adjust;
enum { LONG, INT } intsize;
int fill;
int width, max, len, base;
static char X2C_tab[]= "0123456789ABCDEF";
static char x2c_tab[]= "0123456789abcdef";
char *x2c;
char *p;
long i;
unsigned long u;
char temp[8 * sizeof(long) / 3 + 2];
va_list argp;
va_start(argp, fmt);
while ((c= *fmt++) != 0) {
if (c != '%') {
/* Ordinary character. */
kputc(c);
continue;
}
/* Format specifier of the form:
* %[adjust][fill][width][.max]keys
*/
c= *fmt++;
adjust= RIGHT;
if (c == '-') {
adjust= LEFT;
c= *fmt++;
}
fill= ' ';
if (c == '0') {
fill= '0';
c= *fmt++;
}
width= 0;
if (c == '*') {
/* Width is specified as an argument, e.g. %*d. */
width= va_arg(argp, int);
c= *fmt++;
} else
if (isdigit(c)) {
/* A number tells the width, e.g. %10d. */
do {
width= width * 10 + (c - '0');
} while (isdigit(c= *fmt++));
}
max= INT_MAX;
if (c == '.') {
/* Max field length coming up. */
if ((c= *fmt++) == '*') {
max= va_arg(argp, int);
c= *fmt++;
} else
if (isdigit(c)) {
max= 0;
do {
max= max * 10 + (c - '0');
} while (isdigit(c= *fmt++));
}
}
/* Set a few flags to the default. */
x2c= x2c_tab;
i= 0;
base= 10;
intsize= INT;
if (c == 'l' || c == 'L') {
/* "Long" key, e.g. %ld. */
intsize= LONG;
c= *fmt++;
}
if (c == 0) break;
switch (c) {
/* Decimal. */
case 'd':
i= intsize == LONG ? va_arg(argp, long)
: va_arg(argp, int);
u= i < 0 ? -i : i;
goto int2ascii;
/* Octal. */
case 'o':
base= 010;
goto getint;
/* Pointer, interpret as %X or %lX. */
case 'p':
if (sizeof(char *) > sizeof(int)) intsize= LONG;
/* Hexadecimal. %X prints upper case A-F, not %lx. */
case 'X':
x2c= X2C_tab;
case 'x':
base= 0x10;
goto getint;
/* Unsigned decimal. */
case 'u':
getint:
u= intsize == LONG ? va_arg(argp, unsigned long)
: va_arg(argp, unsigned int);
int2ascii:
p= temp + sizeof(temp)-1;
*p= 0;
do {
*--p= x2c[(ptrdiff_t) (u % base)];
} while ((u /= base) > 0);
goto string_length;
/* A character. */
case 'c':
p= temp;
*p= va_arg(argp, int);
len= 1;
goto string_print;
/* Simply a percent. */
case '%':
p= temp;
*p= '%';
len= 1;
goto string_print;
/* A string. The other cases will join in here. */
case 's':
p= va_arg(argp, char *);
string_length:
for (len= 0; p[len] != 0 && len < max; len++) {}
string_print:
width -= len;
if (i < 0) width--;
if (fill == '0' && i < 0) kputc('-');
if (adjust == RIGHT) {
while (width > 0) { kputc(fill); width--; }
}
if (fill == ' ' && i < 0) kputc('-');
while (len > 0) { kputc((unsigned char) *p++); len--; }
while (width > 0) { kputc(fill); width--; }
break;
/* Unrecognized format key, echo it back. */
default:
kputc('%');
kputc(c);
}
}
/* Mark the end with a null (should be something else, like -1). */
kputc(0);
va_end(argp);
return 0;
}
/*
* $PchId: kprintf.c,v 1.5 1996/04/11 06:59:05 philip Exp $
*/