#include <u.h>
#include <libc.h>
#include <bio.h>

#define	STDIN	0
#define	TABSTOP	5
#define	MAXLINE	1000

int getline(Biobuf *buffer, char line[], int maxline);

/* replace tabs in the input with the proper number of blanks to space to the next tab stop */
void
main()
{
	char line[MAXLINE];
	int len, i, j, k;
	Biobuf *bstdin;
	bstdin = Bfdopen(STDIN, OREAD);

	while((len = getline(bstdin, line, MAXLINE)) > 0){
		for(i = 0, j = 0; i <= len; ++i){
			if(line[i] != '\t'){
				print("%c", line[i]);
				++j;
			}
			else{
				int l = TABSTOP - (j % TABSTOP);
				for(k = 0; k < l; ++k){
					print(" ");
					++j;
				}
			}
		}
	}
}

int getline(Biobuf *b, char s[], int lim)
{
	int c, i;

	for(i = 0; i<lim-1 && (c=Bgetc(b))>= 0 && c!='\n'; ++i)
		s[i] = c;
	if(c == '\n'){
		s[i] = c;
		++i;
	}
	s[i] = '\0';
	return i;
}