Add vis and unvis

1 files changed, 199 insertions, 0 deletions

diff --git a/src/vis.c b/src/vis.c
new file mode 100644
index 0000000..bd3f6f9
--- /dev/null
+++ b/src/vis.c
@@ -0,0 +1,199 @@
+/*-
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. 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 <limits.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <vis.h>
+
+#define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
+
+/*
+ * vis - visually encode characters
+ */
+char *
+vis(dst, c, flag, nextc)
+	char *dst;
+	int c, nextc;
+	int flag;
+{
+	c = (unsigned char)c;
+
+	if (flag & VIS_HTTPSTYLE) {
+		/* Described in RFC 1808 */
+		if (!(isalnum(c) /* alpha-numeric */
+		    /* safe */
+		    || c == '$' || c == '-' || c == '_' || c == '.' || c == '+'
+		    /* extra */
+		    || c == '!' || c == '*' || c == '\'' || c == '('
+		    || c == ')' || c == ',')) {
+			*dst++ = '%';
+			snprintf(dst, 4, (c < 16 ? "0%X" : "%X"), c);
+			dst += 2;
+			goto done;
+		}
+	}
+
+	if ((flag & VIS_GLOB) &&
+	    (c == '*' || c == '?' || c == '[' || c == '#'))
+		;
+	else if (isgraph(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'))) {
+		*dst++ = c;
+		if (c == '\\' && (flag & VIS_NOSLASH) == 0)
+			*dst++ = '\\';
+		*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) == ' ') || isgraph(c) || (flag & VIS_OCTAL)) {
+		*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(c)) {
+		*dst++ = '^';
+		if (c == 0177)
+			*dst++ = '?';
+		else
+			*dst++ = c + '@';
+	} else {
+		*dst++ = '-';
+		*dst++ = c;
+	}
+done:
+	*dst = '\0';
+	return (dst);
+}
+
+/*
+ * strvis, 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 NUL,
+ *	is returned.
+ *
+ *	Strvisx encodes exactly len bytes from src into dst.
+ *	This is useful for encoding a block of data.
+ */
+int
+strvis(dst, src, flag)
+	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
+strvisx(dst, src, len, flag)
+	char *dst;
+	const char *src;
+	size_t len;
+	int flag;
+{
+	int 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);
+}