--- /dev/null
+/* $NetBSD: unvis.c,v 1.30 2009/02/11 13:51:59 christos 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 "config.h"
+#if defined(LIBC_SCCS) && !defined(lint)
+#if 0
+static char sccsid[] = "@(#)unvis.c 8.1 (Berkeley) 6/4/93";
+#else
+__RCSID("$NetBSD: unvis.c,v 1.30 2009/02/11 13:51:59 christos Exp $");
+#endif
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/types.h>
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <vis.h>
+
+#ifdef __weak_alias
+__weak_alias(strunvis,_strunvis)
+#endif
+
+#if !HAVE_VIS
+/*
+ * decode driven by state machine
+ */
+#define S_GROUND 0 /* haven't seen escape char */
+#define S_START 1 /* start decoding special sequence */
+#define S_META 2 /* metachar started (M) */
+#define S_META1 3 /* metachar more, regular char (-) */
+#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 /* http hex digit */
+#define S_HEX2 8 /* http hex digit 2 */
+#define S_MIME1 9 /* mime hex digit 1 */
+#define S_MIME2 10 /* mime hex digit 2 */
+#define S_EATCRNL 11 /* mime eating CRNL */
+
+#define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
+#define xtod(c) (isdigit(c) ? (c - '0') : ((tolower(c) - 'a') + 10))
+#define XTOD(c) (isdigit(c) ? (c - '0') : ((c - 'A') + 10))
+
+/*
+ * unvis - decode characters previously encoded by vis
+ */
+int
+unvis(char *cp, int c, int *astate, int flag)
+{
+ unsigned char uc = (unsigned char)c;
+
+ _DIAGASSERT(cp != NULL);
+ _DIAGASSERT(astate != NULL);
+
+ if (flag & UNVIS_END) {
+ if (*astate == S_OCTAL2 || *astate == S_OCTAL3
+ || *astate == S_HEX2) {
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ }
+ return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD);
+ }
+
+ switch (*astate) {
+
+ case S_GROUND:
+ *cp = 0;
+ if (c == '\\') {
+ *astate = S_START;
+ return UNVIS_NOCHAR;
+ }
+ if ((flag & VIS_HTTPSTYLE) && c == '%') {
+ *astate = S_HEX1;
+ return UNVIS_NOCHAR;
+ }
+ if ((flag & VIS_MIMESTYLE) && c == '=') {
+ *astate = S_MIME1;
+ return UNVIS_NOCHAR;
+ }
+ *cp = c;
+ return UNVIS_VALID;
+
+ case S_START:
+ switch(c) {
+ case '\\':
+ *cp = c;
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case '0': case '1': case '2': case '3':
+ case '4': case '5': case '6': case '7':
+ *cp = (c - '0');
+ *astate = S_OCTAL2;
+ return UNVIS_NOCHAR;
+ case 'M':
+ *cp = (char)0200;
+ *astate = S_META;
+ return UNVIS_NOCHAR;
+ case '^':
+ *astate = S_CTRL;
+ return UNVIS_NOCHAR;
+ case 'n':
+ *cp = '\n';
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case 'r':
+ *cp = '\r';
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case 'b':
+ *cp = '\b';
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case 'a':
+ *cp = '\007';
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case 'v':
+ *cp = '\v';
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case 't':
+ *cp = '\t';
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case 'f':
+ *cp = '\f';
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case 's':
+ *cp = ' ';
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case 'E':
+ *cp = '\033';
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+ case '\n':
+ /*
+ * hidden newline
+ */
+ *astate = S_GROUND;
+ return (UNVIS_NOCHAR);
+ case '$':
+ /*
+ * hidden marker
+ */
+ *astate = S_GROUND;
+ return (UNVIS_NOCHAR);
+ }
+ *astate = S_GROUND;
+ return (UNVIS_SYNBAD);
+
+ case S_META:
+ if (c == '-')
+ *astate = S_META1;
+ else if (c == '^')
+ *astate = S_CTRL;
+ else {
+ *astate = S_GROUND;
+ return (UNVIS_SYNBAD);
+ }
+ return UNVIS_NOCHAR;
+
+ case S_META1:
+ *astate = S_GROUND;
+ *cp |= c;
+ return UNVIS_VALID;
+
+ case S_CTRL:
+ if (c == '?')
+ *cp |= 0177;
+ else
+ *cp |= c & 037;
+ *astate = S_GROUND;
+ return UNVIS_VALID;
+
+ case S_OCTAL2: /* second possible octal digit */
+ if (isoctal(uc)) {
+ /*
+ * yes - and maybe a third
+ */
+ *cp = (*cp << 3) + (c - '0');
+ *astate = S_OCTAL3;
+ return UNVIS_NOCHAR;
+ }
+ /*
+ * no - done with current sequence, push back passed char
+ */
+ *astate = S_GROUND;
+ return UNVIS_VALIDPUSH;
+
+ case S_OCTAL3: /* third possible octal digit */
+ *astate = S_GROUND;
+ if (isoctal(uc)) {
+ *cp = (*cp << 3) + (c - '0');
+ return UNVIS_VALID;
+ }
+ /*
+ * we were done, push back passed char
+ */
+ return UNVIS_VALIDPUSH;
+
+ case S_HEX1:
+ if (isxdigit(uc)) {
+ *cp = xtod(uc);
+ *astate = S_HEX2;
+ return UNVIS_NOCHAR;
+ }
+ /*
+ * no - done with current sequence, push back passed char
+ */
+ *astate = S_GROUND;
+ return UNVIS_VALIDPUSH;
+
+ case S_HEX2:
+ *astate = S_GROUND;
+ if (isxdigit(uc)) {
+ *cp = xtod(uc) | (*cp << 4);
+ return UNVIS_VALID;
+ }
+ return UNVIS_VALIDPUSH;
+
+ case S_MIME1:
+ if (uc == '\n' || uc == '\r') {
+ *astate = S_EATCRNL;
+ return UNVIS_NOCHAR;
+ }
+ if (isxdigit(uc) && (isdigit(uc) || isupper(uc))) {
+ *cp = XTOD(uc);
+ *astate = S_MIME2;
+ return UNVIS_NOCHAR;
+ }
+ *astate = S_GROUND;
+ return UNVIS_SYNBAD;
+
+ case S_MIME2:
+ if (isxdigit(uc) && (isdigit(uc) || isupper(uc))) {
+ *astate = S_GROUND;
+ *cp = XTOD(uc) | (*cp << 4);
+ return UNVIS_VALID;
+ }
+ *astate = S_GROUND;
+ return UNVIS_SYNBAD;
+
+ case S_EATCRNL:
+ switch (uc) {
+ case '\r':
+ case '\n':
+ return UNVIS_NOCHAR;
+ case '=':
+ *astate = S_MIME1;
+ return UNVIS_NOCHAR;
+ default:
+ *cp = uc;
+ return UNVIS_VALID;
+ }
+
+ default:
+ /*
+ * decoder in unknown state - (probably uninitialized)
+ */
+ *astate = S_GROUND;
+ return UNVIS_SYNBAD;
+ }
+}
+
+/*
+ * strunvis - decode src into dst
+ *
+ * Number of chars decoded into dst is returned, -1 on error.
+ * Dst is null terminated.
+ */
+
+int
+strunvisx(dst, src, flag)
+ char *dst;
+ const char *src;
+ int flag;
+{
+ char c;
+ char *start = dst;
+ int state = 0;
+
+ _DIAGASSERT(src != NULL);
+ _DIAGASSERT(dst != NULL);
+
+ while ((c = *src++) != '\0') {
+ again:
+ switch (unvis(dst, c, &state, flag)) {
+ case UNVIS_VALID:
+ dst++;
+ break;
+ case UNVIS_VALIDPUSH:
+ dst++;
+ goto again;
+ case 0:
+ case UNVIS_NOCHAR:
+ break;
+ default:
+ return (-1);
+ }
+ }
+ if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID)
+ dst++;
+ *dst = '\0';
+ return (int)(dst - start);
+}
+
+int
+strunvis(dst, src)
+ char *dst;
+ const char *src;
+{
+ return strunvisx(dst, src, 0);
+}
+#endif