/*
 * uuencode [input] output
 *
 * Encode a file so it can be mailed to a remote system.
 */
#include <u.h>
#include <libc.h>
#include <bio.h>

/* ENC is the basic 1 character encoding function to make a char printing */
#define ENC(c) (((c) & 077) + ' ')

static	void	encode(int, Biobuf*);
static	void	chunk(char*, int, Biobuf*);
static	void	outdec(char*, Biobuf*);

void
main(int argc, char **argv)
{
	Dir *d;
	int fd;
	Biobuf bout;

	/* optional 1st argument */
	if (argc > 2) {
		if ((fd = open(argv[1], OREAD)) < 0) {
			fprint(2, "uuencode: can't open %s: %r\n", argv[1]);
			exits("open");
		}
		argv++; argc--; USED(argv);
	} else
		fd = 0;

	if (argc != 2) {
		fprint(2, "Usage: uuencode [infile] remotefile\n");
		exits("usage");
	}
	Binit(&bout, 1, OWRITE);

	d = dirfstat(fd);
	Bprint(&bout, "begin %ulo %s\n", (d)? d->mode & 0777: 0666, argv[1]);
	free(d);
	encode(fd, &bout);
	Bprint(&bout, "end\n");
	if (Bflush(&bout)) {
		fprint(2, "uuencode: error writing output: %r\n");
		exits("output");
	}
	exits(0);
}

/*
 * copy from in to out, encoding as you go along.
 */
static void
encode(int in, Biobuf *out)
{
	char buf[(Bsize/45)*45];	/* chunks of up to 45 characters */
	char *p;
	int n, r;

	r = 0;
	p = buf;
	while((n = read(in, buf, sizeof(buf))) > 0)
		for(p = buf, r = n; r >= 45; r -= 45, p += 45)
			chunk(p, 45, out);
	if(n < 0) {
		fprint(2, "uuencode: read error: %r\n");
		exits("read");
	}
	if(r)
		chunk(p, r, out);
	chunk(buf, 0, out);
}

static void
chunk(char *p, int n, Biobuf *out)
{
	int i;

	BPUTC(out, ENC(n));
	for(i = 0; i < n; i += 3)
		outdec(p+i, out);
	BPUTC(out, '\n');
}

/*
 * output one group of 3 bytes, pointed at by p, on file f.
 */
static void
outdec(char *p, Biobuf *f)
{
	int c1, c2, c3, c4;

	c1 = *p >> 2;
	c2 = (*p << 4) & 060 | (p[1] >> 4) & 017;
	c3 = (p[1] << 2) & 074 | (p[2] >> 6) & 03;
	c4 = p[2] & 077;
	BPUTC(f, ENC(c1));
	BPUTC(f, ENC(c2));
	BPUTC(f, ENC(c3));
	BPUTC(f, ENC(c4));
}