usr/src/lib/libc/port/gen/unvis.c

   1 /*      $OpenBSD: unvis.c,v 1.17 2015/09/13 11:32:51 guenther Exp $ */
   2 /*-
   3  * Copyright (c) 1989, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. Neither the name of the University nor the names of its contributors
  15  *    may be used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #include <sys/types.h>
  32 #include <ctype.h>
  33 #include <vis.h>
  34
  35 /*
  36  * decode driven by state machine
  37  */
  38 #define S_GROUND        0       /* haven't seen escape char */
  39 #define S_START         1       /* start decoding special sequence */
  40 #define S_META          2       /* metachar started (M) */
  41 #define S_META1         3       /* metachar more, regular char (-) */
  42 #define S_CTRL          4       /* control char started (^) */
  43 #define S_OCTAL2        5       /* octal digit 2 */
  44 #define S_OCTAL3        6       /* octal digit 3 */
  45
  46 #define isoctal(c)      (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
  47
  48 /*
  49  * unvis - decode characters previously encoded by vis
  50  */
  51 int
  52 unvis(char *cp, char c, int *astate, int flag)
  53 {
  54
  55         if (flag & UNVIS_END) {
  56                 if (*astate == S_OCTAL2 || *astate == S_OCTAL3) {
  57                         *astate = S_GROUND;
  58                         return (UNVIS_VALID);
  59                 }
  60                 return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD);
  61         }
  62
  63         switch (*astate) {
  64
  65         case S_GROUND:
  66                 *cp = 0;
  67                 if (c == '\\') {
  68                         *astate = S_START;
  69                         return (0);
  70                 }
  71                 *cp = c;
  72                 return (UNVIS_VALID);
  73
  74         case S_START:
  75                 switch(c) {
  76                 case '-':
  77                         *cp = 0;
  78                         *astate = S_GROUND;
  79                         return (0);
  80                 case '\\':
  81                 case '"':
  82                         *cp = c;
  83                         *astate = S_GROUND;
  84                         return (UNVIS_VALID);
  85                 case '0': case '1': case '2': case '3':
  86                 case '4': case '5': case '6': case '7':
  87                         *cp = (c - '0');
  88                         *astate = S_OCTAL2;
  89                         return (0);
  90                 case 'M':
  91                         *cp = (char) 0200;
  92                         *astate = S_META;
  93                         return (0);
  94                 case '^':
  95                         *astate = S_CTRL;
  96                         return (0);
  97                 case 'n':
  98                         *cp = '\n';
  99                         *astate = S_GROUND;
 100                         return (UNVIS_VALID);
 101                 case 'r':
 102                         *cp = '\r';
 103                         *astate = S_GROUND;
 104                         return (UNVIS_VALID);
 105                 case 'b':
 106                         *cp = '\b';
 107                         *astate = S_GROUND;
 108                         return (UNVIS_VALID);
 109                 case 'a':
 110                         *cp = '\007';
 111                         *astate = S_GROUND;
 112                         return (UNVIS_VALID);
 113                 case 'v':
 114                         *cp = '\v';
 115                         *astate = S_GROUND;
 116                         return (UNVIS_VALID);
 117                 case 't':
 118                         *cp = '\t';
 119                         *astate = S_GROUND;
 120                         return (UNVIS_VALID);
 121                 case 'f':
 122                         *cp = '\f';
 123                         *astate = S_GROUND;
 124                         return (UNVIS_VALID);
 125                 case 's':
 126                         *cp = ' ';
 127                         *astate = S_GROUND;
 128                         return (UNVIS_VALID);
 129                 case 'E':
 130                         *cp = '\033';
 131                         *astate = S_GROUND;
 132                         return (UNVIS_VALID);
 133                 case '\n':
 134                         /*
 135                          * hidden newline
 136                          */
 137                         *astate = S_GROUND;
 138                         return (UNVIS_NOCHAR);
 139                 case '$':
 140                         /*
 141                          * hidden marker
 142                          */
 143                         *astate = S_GROUND;
 144                         return (UNVIS_NOCHAR);
 145                 }
 146                 *astate = S_GROUND;
 147                 return (UNVIS_SYNBAD);
 148
 149         case S_META:
 150                 if (c == '-')
 151                         *astate = S_META1;
 152                 else if (c == '^')
 153                         *astate = S_CTRL;
 154                 else {
 155                         *astate = S_GROUND;
 156                         return (UNVIS_SYNBAD);
 157                 }
 158                 return (0);
 159
 160         case S_META1:
 161                 *astate = S_GROUND;
 162                 *cp |= c;
 163                 return (UNVIS_VALID);
 164
 165         case S_CTRL:
 166                 if (c == '?')
 167                         *cp |= 0177;
 168                 else
 169                         *cp |= c & 037;
 170                 *astate = S_GROUND;
 171                 return (UNVIS_VALID);
 172
 173         case S_OCTAL2:  /* second possible octal digit */
 174                 if (isoctal(c)) {
 175                         /*
 176                          * yes - and maybe a third
 177                          */
 178                         *cp = (*cp << 3) + (c - '0');
 179                         *astate = S_OCTAL3;
 180                         return (0);
 181                 }
 182                 /*
 183                  * no - done with current sequence, push back passed char
 184                  */
 185                 *astate = S_GROUND;
 186                 return (UNVIS_VALIDPUSH);
 187
 188         case S_OCTAL3:  /* third possible octal digit */
 189                 *astate = S_GROUND;
 190                 if (isoctal(c)) {
 191                         *cp = (*cp << 3) + (c - '0');
 192                         return (UNVIS_VALID);
 193                 }
 194                 /*
 195                  * we were done, push back passed char
 196                  */
 197                 return (UNVIS_VALIDPUSH);
 198
 199         default:
 200                 /*
 201                  * decoder in unknown state - (probably uninitialized)
 202                  */
 203                 *astate = S_GROUND;
 204                 return (UNVIS_SYNBAD);
 205         }
 206 }
 207
 208 /*
 209  * strunvis - decode src into dst
 210  *
 211  *      Number of chars decoded into dst is returned, -1 on error.
 212  *      Dst is null terminated.
 213  */
 214
 215 int
 216 strunvis(char *dst, const char *src)
 217 {
 218         char c;
 219         char *start = dst;
 220         int state = 0;
 221
 222         while ((c = *src++)) {
 223         again:
 224                 switch (unvis(dst, c, &state, 0)) {
 225                 case UNVIS_VALID:
 226                         dst++;
 227                         break;
 228                 case UNVIS_VALIDPUSH:
 229                         dst++;
 230                         goto again;
 231                 case 0:
 232                 case UNVIS_NOCHAR:
 233                         break;
 234                 default:
 235                         *dst = '\0';
 236                         return (-1);
 237                 }
 238         }
 239         if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID)
 240                 dst++;
 241         *dst = '\0';
 242         return (dst - start);
 243 }
 244
 245 ssize_t
 246 strnunvis(char *dst, const char *src, size_t sz)
 247 {
 248         char c, p;
 249         char *start = dst, *end = dst + sz - 1;
 250         int state = 0;
 251
 252         if (sz > 0)
 253                 *end = '\0';
 254         while ((c = *src++)) {
 255         again:
 256                 switch (unvis(&p, c, &state, 0)) {
 257                 case UNVIS_VALID:
 258                         if (dst < end)
 259                                 *dst = p;
 260                         dst++;
 261                         break;
 262                 case UNVIS_VALIDPUSH:
 263                         if (dst < end)
 264                                 *dst = p;
 265                         dst++;
 266                         goto again;
 267                 case 0:
 268                 case UNVIS_NOCHAR:
 269                         break;
 270                 default:
 271                         if (dst <= end)
 272                                 *dst = '\0';
 273                         return (-1);
 274                 }
 275         }
 276         if (unvis(&p, c, &state, UNVIS_END) == UNVIS_VALID) {
 277                 if (dst < end)
 278                         *dst = p;
 279                 dst++;
 280         }
 281         if (dst <= end)
 282                 *dst = '\0';
 283         return (dst - start);
 284 }
 285