gen/FreeBSD/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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)unvis.c     8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/gen/unvis.c,v 1.10 2007/01/09 00:27:56 imp Exp $");
  35
  36 #include <sys/types.h>
  37 #include <ctype.h>
  38 #include <vis.h>
  39
  40 /*
  41  * decode driven by state machine
  42  */
  43 #define S_GROUND        0       /* haven't seen escape char */
  44 #define S_START         1       /* start decoding special sequence */
  45 #define S_META          2       /* metachar started (M) */
  46 #define S_META1         3       /* metachar more, regular char (-) */
  47 #define S_CTRL          4       /* control char started (^) */
  48 #define S_OCTAL2        5       /* octal digit 2 */
  49 #define S_OCTAL3        6       /* octal digit 3 */
  50 #define S_HEX2          7       /* hex digit 2 */
  51
  52 #define S_HTTP          0x080   /* %HEXHEX escape */
  53
  54 #define isoctal(c)      (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
  55 #define ishex(c)        ((((u_char)(c)) >= '0' && ((u_char)(c)) <= '9') || (((u_char)(c)) >= 'a' && ((u_char)(c)) <= 'f'))
  56
  57 /*
  58  * unvis - decode characters previously encoded by vis
  59  */
  60 int
  61 unvis(char *cp, int c, int *astate, int flag)
  62 {
  63
  64         if (flag & UNVIS_END) {
  65                 if (*astate == S_OCTAL2 || *astate == S_OCTAL3) {
  66                         *astate = S_GROUND;
  67                         return (UNVIS_VALID);
  68                 }
  69                 return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD);
  70         }
  71
  72         switch (*astate & ~S_HTTP) {
  73
  74         case S_GROUND:
  75                 *cp = 0;
  76                 if (c == '\\') {
  77                         *astate = S_START;
  78                         return (0);
  79                 }
  80                 if (flag & VIS_HTTPSTYLE && c == '%') {
  81                         *astate = S_START | S_HTTP;
  82                         return (0);
  83                 }
  84                 *cp = c;
  85                 return (UNVIS_VALID);
  86
  87         case S_START:
  88                 if (*astate & S_HTTP) {
  89                     if (ishex(tolower(c))) {
  90                         *cp = isdigit(c) ? (c - '0') : (tolower(c) - 'a');
  91                         *astate = S_HEX2;
  92                         return (0);
  93                     }
  94                 }
  95                 switch(c) {
  96                 case '\\':
  97                         *cp = c;
  98                         *astate = S_GROUND;
  99                         return (UNVIS_VALID);
 100                 case '0': case '1': case '2': case '3':
 101                 case '4': case '5': case '6': case '7':
 102                         *cp = (c - '0');
 103                         *astate = S_OCTAL2;
 104                         return (0);
 105                 case 'M':
 106                         *cp = 0200;
 107                         *astate = S_META;
 108                         return (0);
 109                 case '^':
 110                         *astate = S_CTRL;
 111                         return (0);
 112                 case 'n':
 113                         *cp = '\n';
 114                         *astate = S_GROUND;
 115                         return (UNVIS_VALID);
 116                 case 'r':
 117                         *cp = '\r';
 118                         *astate = S_GROUND;
 119                         return (UNVIS_VALID);
 120                 case 'b':
 121                         *cp = '\b';
 122                         *astate = S_GROUND;
 123                         return (UNVIS_VALID);
 124                 case 'a':
 125                         *cp = '\007';
 126                         *astate = S_GROUND;
 127                         return (UNVIS_VALID);
 128                 case 'v':
 129                         *cp = '\v';
 130                         *astate = S_GROUND;
 131                         return (UNVIS_VALID);
 132                 case 't':
 133                         *cp = '\t';
 134                         *astate = S_GROUND;
 135                         return (UNVIS_VALID);
 136                 case 'f':
 137                         *cp = '\f';
 138                         *astate = S_GROUND;
 139                         return (UNVIS_VALID);
 140                 case 's':
 141                         *cp = ' ';
 142                         *astate = S_GROUND;
 143                         return (UNVIS_VALID);
 144                 case 'E':
 145                         *cp = '\033';
 146                         *astate = S_GROUND;
 147                         return (UNVIS_VALID);
 148                 case '\n':
 149                         /*
 150                          * hidden newline
 151                          */
 152                         *astate = S_GROUND;
 153                         return (UNVIS_NOCHAR);
 154                 case '$':
 155                         /*
 156                          * hidden marker
 157                          */
 158                         *astate = S_GROUND;
 159                         return (UNVIS_NOCHAR);
 160                 }
 161                 *astate = S_GROUND;
 162                 return (UNVIS_SYNBAD);
 163
 164         case S_META:
 165                 if (c == '-')
 166                         *astate = S_META1;
 167                 else if (c == '^')
 168                         *astate = S_CTRL;
 169                 else {
 170                         *astate = S_GROUND;
 171                         return (UNVIS_SYNBAD);
 172                 }
 173                 return (0);
 174
 175         case S_META1:
 176                 *astate = S_GROUND;
 177                 *cp |= c;
 178                 return (UNVIS_VALID);
 179
 180         case S_CTRL:
 181                 if (c == '?')
 182                         *cp |= 0177;
 183                 else
 184                         *cp |= c & 037;
 185                 *astate = S_GROUND;
 186                 return (UNVIS_VALID);
 187
 188         case S_OCTAL2:  /* second possible octal digit */
 189                 if (isoctal(c)) {
 190                         /*
 191                          * yes - and maybe a third
 192                          */
 193                         *cp = (*cp << 3) + (c - '0');
 194                         *astate = S_OCTAL3;
 195                         return (0);
 196                 }
 197                 /*
 198                  * no - done with current sequence, push back passed char
 199                  */
 200                 *astate = S_GROUND;
 201                 return (UNVIS_VALIDPUSH);
 202
 203         case S_OCTAL3:  /* third possible octal digit */
 204                 *astate = S_GROUND;
 205                 if (isoctal(c)) {
 206                         *cp = (*cp << 3) + (c - '0');
 207                         return (UNVIS_VALID);
 208                 }
 209                 /*
 210                  * we were done, push back passed char
 211                  */
 212                 return (UNVIS_VALIDPUSH);
 213
 214         case S_HEX2:    /* second mandatory hex digit */
 215                 if (ishex(tolower(c))) {
 216                         *cp = (isdigit(c) ? (*cp << 4) + (c - '0') : (*cp << 4) + (tolower(c) - 'a' + 10));
 217                 }
 218                 *astate = S_GROUND;
 219                 return (UNVIS_VALID);
 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(char *dst, const char *src)
 239 {
 240         char c;
 241         char *start = dst;
 242         int state = 0;
 243
 244         while ( (c = *src++) ) {
 245         again:
 246                 switch (unvis(dst, c, &state, 0)) {
 247                 case UNVIS_VALID:
 248                         dst++;
 249                         break;
 250                 case UNVIS_VALIDPUSH:
 251                         dst++;
 252                         goto again;
 253                 case 0:
 254                 case UNVIS_NOCHAR:
 255                         break;
 256                 default:
 257                         return (-1);
 258                 }
 259         }
 260         if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID)
 261                 dst++;
 262         *dst = '\0';
 263         return (dst - start);
 264 }
 265
 266 int
 267 strunvisx(char *dst, const char *src, int flag)
 268 {
 269         char c;
 270         char *start = dst;
 271         int state = 0;
 272
 273         while ( (c = *src++) ) {
 274         again:
 275                 switch (unvis(dst, c, &state, flag)) {
 276                 case UNVIS_VALID:
 277                         dst++;
 278                         break;
 279                 case UNVIS_VALIDPUSH:
 280                         dst++;
 281                         goto again;
 282                 case 0:
 283                 case UNVIS_NOCHAR:
 284                         break;
 285                 default:
 286                         return (-1);
 287                 }
 288         }
 289         if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID)
 290                 dst++;
 291         *dst = '\0';
 292         return (dst - start);
 293 }