--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/compat/vis.c	Wed Apr 01 14:57:57 2015 +0200
@@ -0,0 +1,246 @@
+/*	$OpenBSD: vis.c,v 1.25 2015/09/13 11:32:51 guenther Exp $ */
+/*-
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <errno.h>
+#include <ctype.h>
+#include <limits.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "pws-compat.h"
+#include "vis.h"
+
+#define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
+#define	isvisible(c,flag)						\
+	(((c) == '\\' || (flag & VIS_ALL) == 0) &&			\
+	(((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) &&		\
+	(((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') ||	\
+		(flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) ||	\
+	((flag & VIS_SP) == 0 && (c) == ' ') ||				\
+	((flag & VIS_TAB) == 0 && (c) == '\t') ||			\
+	((flag & VIS_NL) == 0 && (c) == '\n') ||			\
+	((flag & VIS_SAFE) && ((c) == '\b' ||				\
+		(c) == '\007' || (c) == '\r' ||				\
+		isgraph((u_char)(c))))))
+
+typedef unsigned int u_int;
+typedef unsigned char u_char;
+
+/*
+ * vis - visually encode characters
+ */
+char *
+vis(char *dst, int c, int flag, int nextc)
+{
+	if (isvisible(c, flag)) {
+		if ((c == '"' && (flag & VIS_DQ) != 0) ||
+		    (c == '\\' && (flag & VIS_NOSLASH) == 0))
+			*dst++ = '\\';
+		*dst++ = c;
+		*dst = '\0';
+		return (dst);
+	}
+
+	if (flag & VIS_CSTYLE) {
+		switch(c) {
+		case '\n':
+			*dst++ = '\\';
+			*dst++ = 'n';
+			goto done;
+		case '\r':
+			*dst++ = '\\';
+			*dst++ = 'r';
+			goto done;
+		case '\b':
+			*dst++ = '\\';
+			*dst++ = 'b';
+			goto done;
+		case '\a':
+			*dst++ = '\\';
+			*dst++ = 'a';
+			goto done;
+		case '\v':
+			*dst++ = '\\';
+			*dst++ = 'v';
+			goto done;
+		case '\t':
+			*dst++ = '\\';
+			*dst++ = 't';
+			goto done;
+		case '\f':
+			*dst++ = '\\';
+			*dst++ = 'f';
+			goto done;
+		case ' ':
+			*dst++ = '\\';
+			*dst++ = 's';
+			goto done;
+		case '\0':
+			*dst++ = '\\';
+			*dst++ = '0';
+			if (isoctal(nextc)) {
+				*dst++ = '0';
+				*dst++ = '0';
+			}
+			goto done;
+		}
+	}
+	if (((c & 0177) == ' ') || (flag & VIS_OCTAL) ||
+	    ((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';
+		goto done;
+	}
+	if ((flag & VIS_NOSLASH) == 0)
+		*dst++ = '\\';
+	if (c & 0200) {
+		c &= 0177;
+		*dst++ = 'M';
+	}
+	if (iscntrl((u_char)c)) {
+		*dst++ = '^';
+		if (c == 0177)
+			*dst++ = '?';
+		else
+			*dst++ = c + '@';
+	} else {
+		*dst++ = '-';
+		*dst++ = c;
+	}
+done:
+	*dst = '\0';
+	return (dst);
+}
+
+/*
+ * strvis, strnvis, strvisx - visually encode characters from src into dst
+ *	
+ *	Dst must be 4 times the size of src to account for possible
+ *	expansion.  The length of dst, not including the trailing NULL,
+ *	is returned. 
+ *
+ *	Strnvis will write no more than siz-1 bytes (and will NULL terminate).
+ *	The number of bytes needed to fully encode the string is returned.
+ *
+ *	Strvisx encodes exactly len bytes from src into dst.
+ *	This is useful for encoding a block of data.
+ */
+int
+strvis(char *dst, const char *src, int flag)
+{
+	char c;
+	char *start;
+
+	for (start = dst; (c = *src);)
+		dst = vis(dst, c, flag, *++src);
+	*dst = '\0';
+	return (dst - start);
+}
+
+int
+strnvis(char *dst, const char *src, size_t siz, int flag)
+{
+	char *start, *end;
+	char tbuf[5];
+	int c, i;
+
+	i = 0;
+	for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {
+		if (isvisible(c, flag)) {
+			if ((c == '"' && (flag & VIS_DQ) != 0) ||
+			    (c == '\\' && (flag & VIS_NOSLASH) == 0)) {
+				/* need space for the extra '\\' */
+				if (dst + 1 >= end) {
+					i = 2;
+					break;
+				}
+				*dst++ = '\\';
+			}
+			i = 1;
+			*dst++ = c;
+			src++;
+		} else {
+			i = vis(tbuf, c, flag, *++src) - tbuf;
+			if (dst + i <= end) {
+				memcpy(dst, tbuf, i);
+				dst += i;
+			} else {
+				src--;
+				break;
+			}
+		}
+	}
+	if (siz > 0)
+		*dst = '\0';
+	if (dst + i > end) {
+		/* adjust return value for truncation */
+		while ((c = *src))
+			dst += vis(tbuf, c, flag, *++src) - tbuf;
+	}
+	return (dst - start);
+}
+
+int
+stravis(char **outp, const char *src, int flag)
+{
+	char *buf;
+	int len, serrno;
+
+	buf = malloc(4 * strlen(src) + 1);
+	if (buf == NULL)
+		return -1;
+	len = strvis(buf, src, flag);
+	serrno = errno;
+	*outp = realloc(buf, len + 1);
+	if (*outp == NULL) {
+		*outp = buf;
+		errno = serrno;
+	}
+	return (len);
+}
+
+int
+strvisx(char *dst, const char *src, size_t len, int flag)
+{
+	char c;
+	char *start;
+
+	for (start = dst; len > 1; len--) {
+		c = *src;
+		dst = vis(dst, c, flag, *++src);
+	}
+	if (len)
+		dst = vis(dst, *src, flag, '\0');
+	*dst = '\0';
+	return (dst - start);
+}