Minix1.5/lib/other/prints.c

#include <lib.h>
/* prints() is like printf(), except that it can only handle %s and %c.  It
 * cannot print any of the numeric types such as %d, %o, etc.  It has the
 * advantage of not requiring the runtime code for converting binary numbers
 * to ASCII, which saves 1K bytes in the object program.  Since many of the
 * small utilities do not need numeric printing, they all use prints.
 */

#include <sys/types.h>
#include <unistd.h>

PRIVATE _PROTOTYPE( void put, (int ch));

#define TRUNC_SIZE 128
char Buf[TRUNC_SIZE], *Bufp;

#define OUT 1

void prints(s, arglist)
_CONST register char *s;
int *arglist;
{
  register w;
  int k, *valp;
  char *p, *p1, c;

  Bufp = Buf;
  valp = (int *) &arglist;
  while (*s != '\0') {
	if (*s != '%') {
		put(*s++);
		continue;
	}
	w = 0;
	s++;
	while (*s >= '0' && *s <= '9') {
		w = 10 * w + (*s - '0');
		s++;
	}

	switch (*s) {
	    case 'c':
		k = *valp++;
		put(k);
		s++;
		continue;
	    case 's':
		p = *((char **) valp);
		valp += sizeof(char *) / sizeof(int);
		p1 = p;
		while (c = *p++) put(c);
		s++;
		if ((k = w - ((int) (p - p1) - 1)) > 0) while (k--)
				put(' ');
		continue;
	    default:
		put('%');
		put(*s++);
		continue;
	}

  }
  write(OUT, Buf, (int) (Bufp - Buf));	/* write everything in one blow. */
}

PRIVATE void put(c)
char c;
{
  if (Bufp < &Buf[TRUNC_SIZE]) *Bufp++ = c;
}