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