shithub: align

ref: 4c0d4746f96e57e216b731662e1641da14c8137a
dir: /align.c/

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

enum {
    Center,
    Right,
};

static void usage(void);
int getwidth(void);

void
main(int argc, char **argv)
{
    int termsize, linelen, align;
    char *iline;
    Biobuf in, out;
    
    int pos = 0; /* silence warnings */    
    
    align = Center;
    ARGBEGIN{
        case 'r': align = Right; break;
        default: usage();
    }ARGEND
    
    termsize = getwidth();
    if(termsize == -1)
        sysfatal("term length: %r");
    
    Binit(&in, 0, OREAD);
    Binit(&out, 1, OWRITE);
    
    while((iline = Brdline(&in, '\n')) != 0){
        linelen = Blinelen(&in);
        if(linelen < termsize) {
            switch(align){
                case Center: pos = (termsize / 2) - (linelen / 2); break;
                case Right:  pos = termsize - linelen; break;
            }
            for(int i = 0; i < pos; i++){
                Bwrite(&out, " ", 1);
            }
        } /* give up and just echo the string if it's longer than the term size */
        Bwrite(&out, iline, linelen);
    }
    
    Bterm(&in);
    Bterm(&out);
}

static void
usage(void)
{
	fprint(2, "usage: %s [-r]\n", argv0);
	exits("usage");
}

/* adapted from mc.c */ 
int
getwidth(void)
{
	int n, fd, linewidth;
	char buf[128], *f[10], *p;

	if(access("/dev/acme", OREAD) >= 0){
		if((fd = open("/dev/acme/ctl", OREAD)) < 0)
			return -1;
		n = read(fd, buf, sizeof buf-1);
		close(fd);
		if(n <= 0)
			return -1;
		buf[n] = 0;
		n = tokenize(buf, f, nelem(f));
		if(n < 7)
			return -1;
		if((font = openfont(nil, f[6])) == nil)
			return -1;
		linewidth = atoi(f[5]) / stringwidth(font, "0");
		return linewidth;
	}

	if((p = getenv("font")) == nil)
		return -1;
	if((font = openfont(nil, p)) == nil)
		return -1;
	if((fd = open("/dev/window", OREAD)) < 0){
		font = nil;
		return -1;
	}
	n = read(fd, buf, 5*12);
	close(fd);
	if(n < 5*12){
		font = nil;
		return -1;
	}
	buf[n] = 0;
	
	/* window stucture:
		4 bit left edge
		1 bit gap
		12 bit scrollbar
		4 bit gap
		text
		4 bit right edge
	*/
	linewidth = atoi(buf+3*12) - atoi(buf+1*12) - (4+1+12+4+4);
	return linewidth / stringwidth(font, "0");
}