Two new flags: VIS_ALL - encode all characters, not just invisible ones

and VIS_HEX - use C89 \xff style hexadecimal encoding.

Teach unvis(3) how to deal with the hex encoding.

feedback and ok millert@ chl@

3 files changed, 77 insertions, 12 deletions

diff --git a/lib/libc/gen/unvis.c b/lib/libc/gen/unvis.c
index 258c2d51996..29c3d0a7913 100644
--- a/lib/libc/gen/unvis.c
+++ b/lib/libc/gen/unvis.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: unvis.c,v 1.12 2005/08/08 08:05:34 espie Exp $ */
+/*	$OpenBSD: unvis.c,v 1.13 2010/08/21 18:59:15 djm Exp $ */
 /*-
  * Copyright (c) 1989, 1993
  *	The Regents of the University of California.  All rights reserved.
@@ -42,8 +42,25 @@
 #define	S_CTRL		4	/* control char started (^) */
 #define	S_OCTAL2	5	/* octal digit 2 */
 #define	S_OCTAL3	6	/* octal digit 3 */
+#define	S_HEX1		7	/* hex digit 1 */
+#define	S_HEX2		8	/* hex digit 2 */
 
 #define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
+#define	ishex(c)	((((u_char)(c)) >= '0' && ((u_char)(c)) <= '9') || \
+			 (((u_char)(c)) >= 'a' && ((u_char)(c)) <= 'f') || \
+			 (((u_char)(c)) >= 'A' && ((u_char)(c)) <= 'F'))
+
+static u_int
+dehex(u_int c)
+{
+	if (c >= '0' && c <= '9')
+		return c - '0';
+	if (c >= 'a' && c <= 'f')
+		return 10 + c - 'a';
+	if (c >= 'A' && c <= 'F')
+		return 10 + c - 'A';
+	return 0;
+}
 
 /*
  * unvis - decode characters previously encoded by vis
@@ -53,7 +70,8 @@ unvis(char *cp, char c, int *astate, int flag)
 {
 
 	if (flag & UNVIS_END) {
-		if (*astate == S_OCTAL2 || *astate == S_OCTAL3) {
+		if (*astate == S_OCTAL2 || *astate == S_OCTAL3 ||
+		    *astate == S_HEX1 || *astate == S_HEX2) {
 			*astate = S_GROUND;
 			return (UNVIS_VALID);
 		} 
@@ -77,6 +95,9 @@ unvis(char *cp, char c, int *astate, int flag)
 			*cp = c;
 			*astate = S_GROUND;
 			return (UNVIS_VALID);
+		case 'x':
+			*astate = S_HEX1;
+			return (0);
 		case '0': case '1': case '2': case '3':
 		case '4': case '5': case '6': case '7':
 			*cp = (c - '0');
@@ -190,7 +211,33 @@ unvis(char *cp, char c, int *astate, int flag)
 		 * we were done, push back passed char
 		 */
 		return (UNVIS_VALIDPUSH);
-			
+
+	case S_HEX1:	/* first possible hex digit */
+		if (ishex(c)) {
+			/* 
+			 * yes - and maybe a second
+			 */
+			*cp = dehex(c);
+			*astate = S_HEX2;	
+			return (0);
+		} 
+		/* 
+		 * no - done with current sequence, push back passed char 
+		 */
+		*astate = S_GROUND;
+		return (UNVIS_VALIDPUSH);
+
+	case S_HEX2:	/* second possible hex digit */
+		*astate = S_GROUND;
+		if (ishex(c)) {
+			*cp = ((u_int)*cp << 4) + dehex(c);
+			return (UNVIS_VALID);
+		}
+		/*
+		 * we were done, push back passed char
+		 */
+		return (UNVIS_VALIDPUSH);
+
 	default:	
 		/* 
 		 * decoder in unknown state - (probably uninitialized) 
diff --git a/lib/libc/gen/vis.3 b/lib/libc/gen/vis.3
index 1fae60697db..ce63c2c49f7 100644
--- a/lib/libc/gen/vis.3
+++ b/lib/libc/gen/vis.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: vis.3,v 1.24 2007/05/31 19:19:29 jmc Exp $
+.\"	$OpenBSD: vis.3,v 1.25 2010/08/21 18:59:15 djm Exp $
 .\"
 .\" Copyright (c) 1989, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -27,7 +27,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: May 31 2007 $
+.Dd $Mdocdate: August 21 2010 $
 .Dt VIS 3
 .Os
 .Sh NAME
@@ -163,6 +163,8 @@ except space, tab, and newline are encoded
 The following flags
 alter this:
 .Bl -tag -width VIS_WHITEX
+.It Dv VIS_ALL
+Encode all characters, whether visible or not.
 .It Dv VIS_GLOB
 Also encode magic characters recognized by
 .Xr glob 3
@@ -278,6 +280,13 @@ If
 .Fa nextc
 is an octal digit, the latter representation is used to
 avoid ambiguity.
+.It Dv VIS_HEX
+Use a two digit hexadecimal sequence.
+The form is
+.Ql \exdd
+where
+.Ar d
+represents a hexadecimal digit.
 .It Dv VIS_OCTAL
 Use a three digit octal sequence.
 The form is
diff --git a/lib/libc/gen/vis.c b/lib/libc/gen/vis.c
index 8e44ad733c7..51407e6a7da 100644
--- a/lib/libc/gen/vis.c
+++ b/lib/libc/gen/vis.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vis.c,v 1.19 2005/09/01 17:15:49 millert Exp $ */
+/*	$OpenBSD: vis.c,v 1.20 2010/08/21 18:59:15 djm Exp $ */
 /*-
  * Copyright (c) 1989, 1993
  *	The Regents of the University of California.  All rights reserved.
@@ -46,13 +46,15 @@
 		(c) == '\007' || (c) == '\r' ||				\
 		isgraph((u_char)(c)))))
 
+static const char hexdigits[] = "0123456789abcdef";
+
 /*
  * vis - visually encode characters
  */
 char *
 vis(char *dst, int c, int flag, int nextc)
 {
-	if (isvisible(c)) {
+	if (isvisible(c) && (flag & VIS_ALL) == 0) {
 		*dst++ = c;
 		if (c == '\\' && (flag & VIS_NOSLASH) == 0)
 			*dst++ = '\\';
@@ -104,12 +106,19 @@ vis(char *dst, int c, int flag, int nextc)
 			goto done;
 		}
 	}
-	if (((c & 0177) == ' ') || (flag & VIS_OCTAL) ||
+	if (((c & 0177) == ' ') || (flag & (VIS_OCTAL|VIS_HEX)) ||
 	    ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) {
-		*dst++ = '\\';
-		*dst++ = ((u_char)c >> 6 & 07) + '0';
-		*dst++ = ((u_char)c >> 3 & 07) + '0';
-		*dst++ = ((u_char)c & 07) + '0';
+		if ((flag & VIS_HEX) != 0) {
+			*dst++ = '\\';
+			*dst++ = 'x';
+			*dst++ = hexdigits[((u_char)c >> 4 & 0xf)];
+			*dst++ = hexdigits[((u_char)c & 0xf)];
+		} else {
+			*dst++ = '\\';
+			*dst++ = ((u_char)c >> 6 & 07) + '0';
+			*dst++ = ((u_char)c >> 3 & 07) + '0';
+			*dst++ = ((u_char)c & 07) + '0';
+		}
 		goto done;
 	}
 	if ((flag & VIS_NOSLASH) == 0)