imap4d: simplify auth with encodefmt (backport from 9front)

sys/src/cmd/upas/imap4d/auth.c

@@ -151,19 +151,13 @@ char*
 cramauth(void)
 {
 	char *s, *t;
-	int n;
 	AuthInfo *ai;
 	Chalstate *cs;
 
 	if((cs = auth_challenge("proto=cram role=server")) == nil)
 		return Ebadch;
 
-	n = cs->nchal;
-	s = binalloc(&parsebin, n * 2, 0);
-	n = enc64(s, n * 2, (uchar*)cs->chal, n);
-	Bprint(&bout, "+ ");
-	Bwrite(&bout, s, n);
-	Bprint(&bout, "\r\n");
+	Bprint(&bout, "+ %.*[\r\n", cs->nchal, cs->chal);
 	if(Bflush(&bout) < 0)
 		writeerr();
 
@@ -221,7 +215,6 @@ passauth(char *u, char *secret)
 {
 	char response[2*MD5dlen + 1];
 	uchar digest[MD5dlen];
-	int i;
 	AuthInfo *ai;
 	Chalstate *cs;
 
@@ -229,8 +222,7 @@ passauth(char *u, char *secret)
 		return Ebadch;
 	hmac_md5((uchar*)cs->chal, strlen(cs->chal),
 		(uchar*)secret, strlen(secret), digest, nil);
-	for(i = 0; i < MD5dlen; i++)
-		snprint(response + 2*i, sizeof response - 2*i, "%2.2ux", digest[i]);
+	snprint(response, sizeof(response), "%.*H", MD5dlen, digest);
 	cs->user = u;
 	cs->resp = response;
 	cs->nresp = strlen(response);

sys/src/cmd/upas/imap4d/imap4d.c

@@ -223,6 +223,10 @@ main(int argc, char *argv[])
 	fmtinstall('Y', Zfmt);
 	fmtinstall('Z', Zfmt);
 
+	/* for auth */
+	fmtinstall('H', encodefmt);
+	fmtinstall('[', encodefmt);
+
 	preauth = 0;
 	allowpass = 0;
 	allowcr = 0;

sys/src/cmd/upas/imap4d/msg.c

@@ -462,36 +462,6 @@ msgstruct(Msg *m, int top)
 	return 1;
 }
 
-/*
- *  stolen from upas/marshal; base64 encodes from one fd to another.
- *
- *  the size of buf is very important to enc64.  Anything other than
- *  a multiple of 3 will cause enc64 to output a termination sequence.
- *  To ensure that a full buf corresponds to a multiple of complete lines,
- *  we make buf a multiple of 3*18 since that's how many enc64 sticks on
- *  a single line.  This avoids short lines in the output which is pleasing
- *  but not necessary.
- */
-static int
-enc64x18(char *out, int lim, uchar *in, int n)
-{
-	int m, mm, nn;
-
-	nn = 0;
-	for(; n > 0; n -= m){
-		m = 18 * 3;
-		if(m > n)
-			m = n;
-		mm = enc64(out, lim - nn, in, m);
-		in += m;
-		out += mm;
-		*out++ = '\r';
-		*out++ = '\n';
-		nn += mm + 2;
-	}
-	return nn;
-}
-
 /*
  * read in the message body to count \n without a preceding \r
  */