/* $NetBSD: unvis.c,v 1.45 2022/04/19 20:32:15 rillig 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/cdefs.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 1.45 2022/04/19 20:32:15 rillig Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <assert.h>
#include <ctype.h>
#include <stdint.h>
#include <stdio.h>
#include <errno.h>
#include <vis.h>
#ifdef __weak_alias
__weak_alias(strnunvisx,_strnunvisx)
#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_HEX 7 /* mandatory hex digit */
#define S_HEX1 8 /* http hex digit */
#define S_HEX2 9 /* http hex digit 2 */
#define S_MIME1 10 /* mime hex digit 1 */
#define S_MIME2 11 /* mime hex digit 2 */
#define S_EATCRNL 12 /* mime eating CRNL */
#define S_AMP 13 /* seen & */
#define S_NUMBER 14 /* collecting number */
#define S_STRING 15 /* collecting string */
#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))
/*
* RFC 1866
*/
static const struct nv {
char name[7];
uint8_t value;
} nv[] = {
{ "AElig", 198 }, /* capital AE diphthong (ligature) */
{ "Aacute", 193 }, /* capital A, acute accent */
{ "Acirc", 194 }, /* capital A, circumflex accent */
{ "Agrave", 192 }, /* capital A, grave accent */
{ "Aring", 197 }, /* capital A, ring */
{ "Atilde", 195 }, /* capital A, tilde */
{ "Auml", 196 }, /* capital A, dieresis or umlaut mark */
{ "Ccedil", 199 }, /* capital C, cedilla */
{ "ETH", 208 }, /* capital Eth, Icelandic */
{ "Eacute", 201 }, /* capital E, acute accent */
{ "Ecirc", 202 }, /* capital E, circumflex accent */
{ "Egrave", 200 }, /* capital E, grave accent */
{ "Euml", 203 }, /* capital E, dieresis or umlaut mark */
{ "Iacute", 205 }, /* capital I, acute accent */
{ "Icirc", 206 }, /* capital I, circumflex accent */
{ "Igrave", 204 }, /* capital I, grave accent */
{ "Iuml", 207 }, /* capital I, dieresis or umlaut mark */
{ "Ntilde", 209 }, /* capital N, tilde */
{ "Oacute", 211 }, /* capital O, acute accent */
{ "Ocirc", 212 }, /* capital O, circumflex accent */
{ "Ograve", 210 }, /* capital O, grave accent */
{ "Oslash", 216 }, /* capital O, slash */
{ "Otilde", 213 }, /* capital O, tilde */
{ "Ouml", 214 }, /* capital O, dieresis or umlaut mark */
{ "THORN", 222 }, /* capital THORN, Icelandic */
{ "Uacute", 218 }, /* capital U, acute accent */
{ "Ucirc", 219 }, /* capital U, circumflex accent */
{ "Ugrave", 217 }, /* capital U, grave accent */
{ "Uuml", 220 }, /* capital U, dieresis or umlaut mark */
{ "Yacute", 221 }, /* capital Y, acute accent */
{ "aacute", 225 }, /* small a, acute accent */
{ "acirc", 226 }, /* small a, circumflex accent */
{ "acute", 180 }, /* acute accent */
{ "aelig", 230 }, /* small ae diphthong (ligature) */
{ "agrave", 224 }, /* small a, grave accent */
{ "amp", 38 }, /* ampersand */
{ "aring", 229 }, /* small a, ring */
{ "atilde", 227 }, /* small a, tilde */
{ "auml", 228 }, /* small a, dieresis or umlaut mark */
{ "brvbar", 166 }, /* broken (vertical) bar */
{ "ccedil", 231 }, /* small c, cedilla */
{ "cedil", 184 }, /* cedilla */
{ "cent", 162 }, /* cent sign */
{ "copy", 169 }, /* copyright sign */
{ "curren", 164 }, /* general currency sign */
{ "deg", 176 }, /* degree sign */
{ "divide", 247 }, /* divide sign */
{ "eacute", 233 }, /* small e, acute accent */
{ "ecirc", 234 }, /* small e, circumflex accent */
{ "egrave", 232 }, /* small e, grave accent */
{ "eth", 240 }, /* small eth, Icelandic */
{ "euml", 235 }, /* small e, dieresis or umlaut mark */
{ "frac12", 189 }, /* fraction one-half */
{ "frac14", 188 }, /* fraction one-quarter */
{ "frac34", 190 }, /* fraction three-quarters */
{ "gt", 62 }, /* greater than */
{ "iacute", 237 }, /* small i, acute accent */
{ "icirc", 238 }, /* small i, circumflex accent */
{ "iexcl", 161 }, /* inverted exclamation mark */
{ "igrave", 236 }, /* small i, grave accent */
{ "iquest", 191 }, /* inverted question mark */
{ "iuml", 239 }, /* small i, dieresis or umlaut mark */
{ "laquo", 171 }, /* angle quotation mark, left */
{ "lt", 60 }, /* less than */
{ "macr", 175 }, /* macron */
{ "micro", 181 }, /* micro sign */
{ "middot", 183 }, /* middle dot */
{ "nbsp", 160 }, /* no-break space */
{ "not", 172 }, /* not sign */
{ "ntilde", 241 }, /* small n, tilde */
{ "oacute", 243 }, /* small o, acute accent */
{ "ocirc", 244 }, /* small o, circumflex accent */
{ "ograve", 242 }, /* small o, grave accent */
{ "ordf", 170 }, /* ordinal indicator, feminine */
{ "ordm", 186 }, /* ordinal indicator, masculine */
{ "oslash", 248 }, /* small o, slash */
{ "otilde", 245 }, /* small o, tilde */
{ "ouml", 246 }, /* small o, dieresis or umlaut mark */
{ "para", 182 }, /* pilcrow (paragraph sign) */
{ "plusmn", 177 }, /* plus-or-minus sign */
{ "pound", 163 }, /* pound sterling sign */
{ "quot", 34 }, /* double quote */
{ "raquo", 187 }, /* angle quotation mark, right */
{ "reg", 174 }, /* registered sign */
{ "sect", 167 }, /* section sign */
{ "shy", 173 }, /* soft hyphen */
{ "sup1", 185 }, /* superscript one */
{ "sup2", 178 }, /* superscript two */
{ "sup3", 179 }, /* superscript three */
{ "szlig", 223 }, /* small sharp s, German (sz ligature) */
{ "thorn", 254 }, /* small thorn, Icelandic */
{ "times", 215 }, /* multiply sign */
{ "uacute", 250 }, /* small u, acute accent */
{ "ucirc", 251 }, /* small u, circumflex accent */
{ "ugrave", 249 }, /* small u, grave accent */
{ "uml", 168 }, /* umlaut (dieresis) */
{ "uuml", 252 }, /* small u, dieresis or umlaut mark */
{ "yacute", 253 }, /* small y, acute accent */
{ "yen", 165 }, /* yen sign */
{ "yuml", 255 }, /* small y, dieresis or umlaut mark */
};
/*
* unvis - decode characters previously encoded by vis
*/
int
unvis(char *cp, int c, int *astate, int flag)
{
unsigned char uc = (unsigned char)c;
unsigned char st, ia, is, lc;
/*
* Bottom 8 bits of astate hold the state machine state.
* Top 8 bits hold the current character in the http 1866 nv string decoding
*/
#define GS(a) ((a) & 0xff)
#define SS(a, b) (((uint32_t)(a) << 24) | (b))
#define GI(a) ((uint32_t)(a) >> 24)
_DIAGASSERT(cp != NULL);
_DIAGASSERT(astate != NULL);
st = GS(*astate);
if (flag & UNVIS_END) {
switch (st) {
case S_OCTAL2:
case S_OCTAL3:
case S_HEX2:
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case S_GROUND:
return UNVIS_NOCHAR;
default:
return UNVIS_SYNBAD;
}
}
switch (st) {
case S_GROUND:
*cp = 0;
if ((flag & VIS_NOESCAPE) == 0 && c == '\\') {
*astate = SS(0, S_START);
return UNVIS_NOCHAR;
}
if ((flag & VIS_HTTP1808) && c == '%') {
*astate = SS(0, S_HEX1);
return UNVIS_NOCHAR;
}
if ((flag & VIS_HTTP1866) && c == '&') {
*astate = SS(0, S_AMP);
return UNVIS_NOCHAR;
}
if ((flag & VIS_MIMESTYLE) && c == '=') {
*astate = SS(0, S_MIME1);
return UNVIS_NOCHAR;
}
*cp = c;
return UNVIS_VALID;
case S_START:
switch(c) {
case '\\':
*cp = c;
*astate = SS(0, 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 = SS(0, S_OCTAL2);
return UNVIS_NOCHAR;
case 'M':
*cp = (char)0200;
*astate = SS(0, S_META);
return UNVIS_NOCHAR;
case '^':
*astate = SS(0, S_CTRL);
return UNVIS_NOCHAR;
case 'n':
*cp = '\n';
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case 'r':
*cp = '\r';
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case 'b':
*cp = '\b';
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case 'a':
*cp = '\007';
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case 'v':
*cp = '\v';
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case 't':
*cp = '\t';
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case 'f':
*cp = '\f';
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case 's':
*cp = ' ';
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case 'E':
*cp = '\033';
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case 'x':
*astate = SS(0, S_HEX);
return UNVIS_NOCHAR;
case '\n':
/*
* hidden newline
*/
*astate = SS(0, S_GROUND);
return UNVIS_NOCHAR;
case '$':
/*
* hidden marker
*/
*astate = SS(0, S_GROUND);
return UNVIS_NOCHAR;
default:
if (isgraph(c)) {
*cp = c;
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
}
}
goto bad;
case S_META:
if (c == '-')
*astate = SS(0, S_META1);
else if (c == '^')
*astate = SS(0, S_CTRL);
else
goto bad;
return UNVIS_NOCHAR;
case S_META1:
*astate = SS(0, S_GROUND);
*cp |= c;
return UNVIS_VALID;
case S_CTRL:
if (c == '?')
*cp |= 0177;
else
*cp |= c & 037;
*astate = SS(0, 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 = SS(0, S_OCTAL3);
return UNVIS_NOCHAR;
}
/*
* no - done with current sequence, push back passed char
*/
*astate = SS(0, S_GROUND);
return UNVIS_VALIDPUSH;
case S_OCTAL3: /* third possible octal digit */
*astate = SS(0, 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_HEX:
if (!isxdigit(uc))
goto bad;
/*FALLTHROUGH*/
case S_HEX1:
if (isxdigit(uc)) {
*cp = xtod(uc);
*astate = SS(0, S_HEX2);
return UNVIS_NOCHAR;
}
/*
* no - done with current sequence, push back passed char
*/
*astate = SS(0, 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 = SS(0, S_EATCRNL);
return UNVIS_NOCHAR;
}
if (isxdigit(uc) && (isdigit(uc) || isupper(uc))) {
*cp = XTOD(uc);
*astate = SS(0, S_MIME2);
return UNVIS_NOCHAR;
}
goto bad;
case S_MIME2:
if (isxdigit(uc) && (isdigit(uc) || isupper(uc))) {
*astate = SS(0, S_GROUND);
*cp = XTOD(uc) | (*cp << 4);
return UNVIS_VALID;
}
goto bad;
case S_EATCRNL:
switch (uc) {
case '\r':
case '\n':
return UNVIS_NOCHAR;
case '=':
*astate = SS(0, S_MIME1);
return UNVIS_NOCHAR;
default:
*cp = uc;
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
}
case S_AMP:
*cp = 0;
if (uc == '#') {
*astate = SS(0, S_NUMBER);
return UNVIS_NOCHAR;
}
*astate = SS(0, S_STRING);
/*FALLTHROUGH*/
case S_STRING:
ia = *cp; /* index in the array */
is = GI(*astate); /* index in the string */
lc = is == 0 ? 0 : nv[ia].name[is - 1]; /* last character */
if (uc == ';')
uc = '\0';
for (; ia < __arraycount(nv); ia++) {
if (is != 0 && nv[ia].name[is - 1] != lc)
goto bad;
if (nv[ia].name[is] == uc)
break;
}
if (ia == __arraycount(nv))
goto bad;
if (uc != 0) {
*cp = ia;
*astate = SS(is + 1, S_STRING);
return UNVIS_NOCHAR;
}
*cp = nv[ia].value;
*astate = SS(0, S_GROUND);
return UNVIS_VALID;
case S_NUMBER:
if (uc == ';')
return UNVIS_VALID;
if (!isdigit(uc))
goto bad;
*cp += (*cp * 10) + uc - '0';
return UNVIS_NOCHAR;
default:
bad:
/*
* decoder in unknown state - (probably uninitialized)
*/
*astate = SS(0, S_GROUND);
return UNVIS_SYNBAD;
}
}
/*
* strnunvisx - decode src into dst
*
* Number of chars decoded into dst is returned, -1 on error.
* Dst is null terminated.
*/
int
strnunvisx(char *dst, size_t dlen, const char *src, int flag)
{
char c;
char t = '\0', *start = dst;
int state = 0;
_DIAGASSERT(src != NULL);
_DIAGASSERT(dst != NULL);
#define CHECKSPACE() \
do { \
if (dlen-- == 0) { \
errno = ENOSPC; \
return -1; \
} \
} while (0)
while ((c = *src++) != '\0') {
again:
switch (unvis(&t, c, &state, flag)) {
case UNVIS_VALID:
CHECKSPACE();
*dst++ = t;
break;
case UNVIS_VALIDPUSH:
CHECKSPACE();
*dst++ = t;
goto again;
case 0:
case UNVIS_NOCHAR:
break;
case UNVIS_SYNBAD:
errno = EINVAL;
return -1;
default:
_DIAGASSERT(/*CONSTCOND*/0);
errno = EINVAL;
return -1;
}
}
if (unvis(&t, c, &state, UNVIS_END) == UNVIS_VALID) {
CHECKSPACE();
*dst++ = t;
}
CHECKSPACE();
*dst = '\0';
return (int)(dst - start);
}
int
strunvisx(char *dst, const char *src, int flag)
{
return strnunvisx(dst, (size_t)~0, src, flag);
}
int
strunvis(char *dst, const char *src)
{
return strnunvisx(dst, (size_t)~0, src, 0);
}
int
strnunvis(char *dst, size_t dlen, const char *src)
{
return strnunvisx(dst, dlen, src, 0);
}
#endif
