src/libs/bsd/unvis.c

   1 /*-
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)unvis.c     8.1 (Berkeley) 6/4/93";
  36 #endif /* LIBC_SCCS and not lint */
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD: src/lib/libc/gen/unvis.c,v 1.9 2004/08/02 08:46:23 stefanf Exp $");
  39
  40 #include <sys/types.h>
  41 #include <ctype.h>
  42 #include <vis.h>
  43
  44 /*
  45  * decode driven by state machine
  46  */
  47 #define S_GROUND        0       /* haven't seen escape char */
  48 #define S_START         1       /* start decoding special sequence */
  49 #define S_META          2       /* metachar started (M) */
  50 #define S_META1         3       /* metachar more, regular char (-) */
  51 #define S_CTRL          4       /* control char started (^) */
  52 #define S_OCTAL2        5       /* octal digit 2 */
  53 #define S_OCTAL3        6       /* octal digit 3 */
  54 #define S_HEX2          7       /* hex digit 2 */
  55
  56 #define S_HTTP          0x080   /* %HEXHEX escape */
  57
  58 #define isoctal(c)      (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
  59 #define ishex(c)        ((((u_char)(c)) >= '0' && ((u_char)(c)) <= '9') || (((u_char)(c)) >= 'a' && ((u_char)(c)) <= 'f'))
  60
  61 /*
  62  * unvis - decode characters previously encoded by vis
  63  */
  64 int
  65 unvis(char *cp, int c, int *astate, int flag)
  66 {
  67
  68         if (flag & UNVIS_END) {
  69                 if (*astate == S_OCTAL2 || *astate == S_OCTAL3) {
  70                         *astate = S_GROUND;
  71                         return (UNVIS_VALID);
  72                 }
  73                 return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD);
  74         }
  75
  76         switch (*astate & ~S_HTTP) {
  77
  78         case S_GROUND:
  79                 *cp = 0;
  80                 if (c == '\\') {
  81                         *astate = S_START;
  82                         return (0);
  83                 }
  84                 if (flag & VIS_HTTPSTYLE && c == '%') {
  85                         *astate = S_START | S_HTTP;
  86                         return (0);
  87                 }
  88                 *cp = c;
  89                 return (UNVIS_VALID);
  90
  91         case S_START:
  92                 if (*astate & S_HTTP) {
  93                     if (ishex(tolower(c))) {
  94                         *cp = isdigit(c) ? (c - '0') : (tolower(c) - 'a');
  95                         *astate = S_HEX2;
  96                         return (0);
  97                     }
  98                 }
  99                 switch(c) {
 100                 case '\\':
 101                         *cp = c;
 102                         *astate = S_GROUND;
 103                         return (UNVIS_VALID);
 104                 case '0': case '1': case '2': case '3':
 105                 case '4': case '5': case '6': case '7':
 106                         *cp = (c - '0');
 107                         *astate = S_OCTAL2;
 108                         return (0);
 109                 case 'M':
 110                         *cp = 0200;
 111                         *astate = S_META;
 112                         return (0);
 113                 case '^':
 114                         *astate = S_CTRL;
 115                         return (0);
 116                 case 'n':
 117                         *cp = '\n';
 118                         *astate = S_GROUND;
 119                         return (UNVIS_VALID);
 120                 case 'r':
 121                         *cp = '\r';
 122                         *astate = S_GROUND;
 123                         return (UNVIS_VALID);
 124                 case 'b':
 125                         *cp = '\b';
 126                         *astate = S_GROUND;
 127                         return (UNVIS_VALID);
 128                 case 'a':
 129                         *cp = '\007';
 130                         *astate = S_GROUND;
 131                         return (UNVIS_VALID);
 132                 case 'v':
 133                         *cp = '\v';
 134                         *astate = S_GROUND;
 135                         return (UNVIS_VALID);
 136                 case 't':
 137                         *cp = '\t';
 138                         *astate = S_GROUND;
 139                         return (UNVIS_VALID);
 140                 case 'f':
 141                         *cp = '\f';
 142                         *astate = S_GROUND;
 143                         return (UNVIS_VALID);
 144                 case 's':
 145                         *cp = ' ';
 146                         *astate = S_GROUND;
 147                         return (UNVIS_VALID);
 148                 case 'E':
 149                         *cp = '\033';
 150                         *astate = S_GROUND;
 151                         return (UNVIS_VALID);
 152                 case '\n':
 153                         /*
 154                          * hidden newline
 155                          */
 156                         *astate = S_GROUND;
 157                         return (UNVIS_NOCHAR);
 158                 case '$':
 159                         /*
 160                          * hidden marker
 161                          */
 162                         *astate = S_GROUND;
 163                         return (UNVIS_NOCHAR);
 164                 }
 165                 *astate = S_GROUND;
 166                 return (UNVIS_SYNBAD);
 167
 168         case S_META:
 169                 if (c == '-')
 170                         *astate = S_META1;
 171                 else if (c == '^')
 172                         *astate = S_CTRL;
 173                 else {
 174                         *astate = S_GROUND;
 175                         return (UNVIS_SYNBAD);
 176                 }
 177                 return (0);
 178
 179         case S_META1:
 180                 *astate = S_GROUND;
 181                 *cp |= c;
 182                 return (UNVIS_VALID);
 183
 184         case S_CTRL:
 185                 if (c == '?')
 186                         *cp |= 0177;
 187                 else
 188                         *cp |= c & 037;
 189                 *astate = S_GROUND;
 190                 return (UNVIS_VALID);
 191
 192         case S_OCTAL2:  /* second possible octal digit */
 193                 if (isoctal(c)) {
 194                         /*
 195                          * yes - and maybe a third
 196                          */
 197                         *cp = (*cp << 3) + (c - '0');
 198                         *astate = S_OCTAL3;
 199                         return (0);
 200                 }
 201                 /*
 202                  * no - done with current sequence, push back passed char
 203                  */
 204                 *astate = S_GROUND;
 205                 return (UNVIS_VALIDPUSH);
 206
 207         case S_OCTAL3:  /* third possible octal digit */
 208                 *astate = S_GROUND;
 209                 if (isoctal(c)) {
 210                         *cp = (*cp << 3) + (c - '0');
 211                         return (UNVIS_VALID);
 212                 }
 213                 /*
 214                  * we were done, push back passed char
 215                  */
 216                 return (UNVIS_VALIDPUSH);
 217
 218         case S_HEX2:    /* second mandatory hex digit */
 219                 if (ishex(tolower(c))) {
 220                         *cp = (isdigit(c) ? (*cp << 4) + (c - '0') : (*cp << 4) + (tolower(c) - 'a' + 10));
 221                 }
 222                 *astate = S_GROUND;
 223                 return (UNVIS_VALID);
 224
 225         default:
 226                 /*
 227                  * decoder in unknown state - (probably uninitialized)
 228                  */
 229                 *astate = S_GROUND;
 230                 return (UNVIS_SYNBAD);
 231         }
 232 }
 233
 234 /*
 235  * strunvis - decode src into dst
 236  *
 237  *      Number of chars decoded into dst is returned, -1 on error.
 238  *      Dst is null terminated.
 239  */
 240
 241 int
 242 strunvis(char *dst, const char *src)
 243 {
 244         char c;
 245         char *start = dst;
 246         int state = 0;
 247
 248         while ( (c = *src++) ) {
 249         again:
 250                 switch (unvis(dst, c, &state, 0)) {
 251                 case UNVIS_VALID:
 252                         dst++;
 253                         break;
 254                 case UNVIS_VALIDPUSH:
 255                         dst++;
 256                         goto again;
 257                 case 0:
 258                 case UNVIS_NOCHAR:
 259                         break;
 260                 default:
 261                         return (-1);
 262                 }
 263         }
 264         if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID)
 265                 dst++;
 266         *dst = '\0';
 267         return (dst - start);
 268 }
 269
 270 int
 271 strunvisx(char *dst, const char *src, int flag)
 272 {
 273         char c;
 274         char *start = dst;
 275         int state = 0;
 276
 277         while ( (c = *src++) ) {
 278         again:
 279                 switch (unvis(dst, c, &state, flag)) {
 280                 case UNVIS_VALID:
 281                         dst++;
 282                         break;
 283                 case UNVIS_VALIDPUSH:
 284                         dst++;
 285                         goto again;
 286                 case 0:
 287                 case UNVIS_NOCHAR:
 288                         break;
 289                 default:
 290                         return (-1);
 291                 }
 292         }
 293         if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID)
 294                 dst++;
 295         *dst = '\0';
 296         return (dst - start);
 297 }