gen/unvis.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1989, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  * 3. All advertising materials mentioning features or use of this software
  35  *    must display the following acknowledgement:
  36  *      This product includes software developed by the University of
  37  *      California, Berkeley and its contributors.
  38  * 4. Neither the name of the University nor the names of its contributors
  39  *    may be used to endorse or promote products derived from this software
  40  *    without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  */
  54
  55
  56 #include <sys/types.h>
  57 #include <ctype.h>
  58 #include <vis.h>
  59
  60 /*
  61  * decode driven by state machine
  62  */
  63 #define S_GROUND        0       /* haven't seen escape char */
  64 #define S_START         1       /* start decoding special sequence */
  65 #define S_META          2       /* metachar started (M) */
  66 #define S_META1         3       /* metachar more, regular char (-) */
  67 #define S_CTRL          4       /* control char started (^) */
  68 #define S_OCTAL2        5       /* octal digit 2 */
  69 #define S_OCTAL3        6       /* octal digit 3 */
  70
  71 #define isoctal(c)      (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
  72
  73 /*
  74  * unvis - decode characters previously encoded by vis
  75  */
  76 int
  77 unvis(cp, c, astate, flag)
  78         char *cp;
  79         int c, *astate, flag;
  80 {
  81
  82         if (flag & UNVIS_END) {
  83                 if (*astate == S_OCTAL2 || *astate == S_OCTAL3) {
  84                         *astate = S_GROUND;
  85                         return (UNVIS_VALID);
  86                 }
  87                 return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD);
  88         }
  89
  90         switch (*astate) {
  91
  92         case S_GROUND:
  93                 *cp = 0;
  94                 if (c == '\\') {
  95                         *astate = S_START;
  96                         return (0);
  97                 }
  98                 *cp = c;
  99                 return (UNVIS_VALID);
 100
 101         case S_START:
 102                 switch(c) {
 103                 case '\\':
 104                         *cp = c;
 105                         *astate = S_GROUND;
 106                         return (UNVIS_VALID);
 107                 case '0': case '1': case '2': case '3':
 108                 case '4': case '5': case '6': case '7':
 109                         *cp = (c - '0');
 110                         *astate = S_OCTAL2;
 111                         return (0);
 112                 case 'M':
 113                         *cp = 0200;
 114                         *astate = S_META;
 115                         return (0);
 116                 case '^':
 117                         *astate = S_CTRL;
 118                         return (0);
 119                 case 'n':
 120                         *cp = '\n';
 121                         *astate = S_GROUND;
 122                         return (UNVIS_VALID);
 123                 case 'r':
 124                         *cp = '\r';
 125                         *astate = S_GROUND;
 126                         return (UNVIS_VALID);
 127                 case 'b':
 128                         *cp = '\b';
 129                         *astate = S_GROUND;
 130                         return (UNVIS_VALID);
 131                 case 'a':
 132                         *cp = '\007';
 133                         *astate = S_GROUND;
 134                         return (UNVIS_VALID);
 135                 case 'v':
 136                         *cp = '\v';
 137                         *astate = S_GROUND;
 138                         return (UNVIS_VALID);
 139                 case 't':
 140                         *cp = '\t';
 141                         *astate = S_GROUND;
 142                         return (UNVIS_VALID);
 143                 case 'f':
 144                         *cp = '\f';
 145                         *astate = S_GROUND;
 146                         return (UNVIS_VALID);
 147                 case 's':
 148                         *cp = ' ';
 149                         *astate = S_GROUND;
 150                         return (UNVIS_VALID);
 151                 case 'E':
 152                         *cp = '\033';
 153                         *astate = S_GROUND;
 154                         return (UNVIS_VALID);
 155                 case '\n':
 156                         /*
 157                          * hidden newline
 158                          */
 159                         *astate = S_GROUND;
 160                         return (UNVIS_NOCHAR);
 161                 case '$':
 162                         /*
 163                          * hidden marker
 164                          */
 165                         *astate = S_GROUND;
 166                         return (UNVIS_NOCHAR);
 167                 }
 168                 *astate = S_GROUND;
 169                 return (UNVIS_SYNBAD);
 170
 171         case S_META:
 172                 if (c == '-')
 173                         *astate = S_META1;
 174                 else if (c == '^')
 175                         *astate = S_CTRL;
 176                 else {
 177                         *astate = S_GROUND;
 178                         return (UNVIS_SYNBAD);
 179                 }
 180                 return (0);
 181
 182         case S_META1:
 183                 *astate = S_GROUND;
 184                 *cp |= c;
 185                 return (UNVIS_VALID);
 186
 187         case S_CTRL:
 188                 if (c == '?')
 189                         *cp |= 0177;
 190                 else
 191                         *cp |= c & 037;
 192                 *astate = S_GROUND;
 193                 return (UNVIS_VALID);
 194
 195         case S_OCTAL2:  /* second possible octal digit */
 196                 if (isoctal(c)) {
 197                         /*
 198                          * yes - and maybe a third
 199                          */
 200                         *cp = (*cp << 3) + (c - '0');
 201                         *astate = S_OCTAL3;
 202                         return (0);
 203                 }
 204                 /*
 205                  * no - done with current sequence, push back passed char
 206                  */
 207                 *astate = S_GROUND;
 208                 return (UNVIS_VALIDPUSH);
 209
 210         case S_OCTAL3:  /* third possible octal digit */
 211                 *astate = S_GROUND;
 212                 if (isoctal(c)) {
 213                         *cp = (*cp << 3) + (c - '0');
 214                         return (UNVIS_VALID);
 215                 }
 216                 /*
 217                  * we were done, push back passed char
 218                  */
 219                 return (UNVIS_VALIDPUSH);
 220
 221         default:
 222                 /*
 223                  * decoder in unknown state - (probably uninitialized)
 224                  */
 225                 *astate = S_GROUND;
 226                 return (UNVIS_SYNBAD);
 227         }
 228 }
 229
 230 /*
 231  * strunvis - decode src into dst
 232  *
 233  *      Number of chars decoded into dst is returned, -1 on error.
 234  *      Dst is null terminated.
 235  */
 236
 237 int
 238 strunvis(dst, src)
 239         register char *dst;
 240         register const char *src;
 241 {
 242         register char c;
 243         char *start = dst;
 244         int state = 0;
 245
 246         while (c = *src++) {
 247         again:
 248                 switch (unvis(dst, c, &state, 0)) {
 249                 case UNVIS_VALID:
 250                         dst++;
 251                         break;
 252                 case UNVIS_VALIDPUSH:
 253                         dst++;
 254                         goto again;
 255                 case 0:
 256                 case UNVIS_NOCHAR:
 257                         break;
 258                 default:
 259                         return (-1);
 260                 }
 261         }
 262         if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID)
 263                 dst++;
 264         *dst = '\0';
 265         return (dst - start);
 266 }