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 * $FreeBSD: src/lib/libc/gen/unvis.c,v 1.4.8.1 2000/08/17 08:25:54 jhb Exp $ 34 * $DragonFly: src/lib/libc/gen/unvis.c,v 1.3 2004/06/06 15:05:55 hmp Exp $ 35 * 36 * @(#)unvis.c 8.1 (Berkeley) 6/4/93 37 */ 38 39 #include <sys/types.h> 40 #include <vis.h> 41 42 /* 43 * decode driven by state machine 44 */ 45 #define S_GROUND 0 /* haven't seen escape char */ 46 #define S_START 1 /* start decoding special sequence */ 47 #define S_META 2 /* metachar started (M) */ 48 #define S_META1 3 /* metachar more, regular char (-) */ 49 #define S_CTRL 4 /* control char started (^) */ 50 #define S_OCTAL2 5 /* octal digit 2 */ 51 #define S_OCTAL3 6 /* octal digit 3 */ 52 #define S_HEX2 7 /* hex digit 2 */ 53 54 #define S_HTTP 0x080 /* %HEXHEX escape */ 55 56 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7') 57 #define ishex(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '9' || ((u_char)(c)) >= 'a' && ((u_char)(c)) <= 'f') 58 59 /* 60 * unvis - decode characters previously encoded by vis 61 */ 62 int 63 unvis(cp, c, astate, flag) 64 char *cp; 65 int c, *astate, 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(dst, src) 243 char *dst; 244 const char *src; 245 { 246 char c; 247 char *start = dst; 248 int state = 0; 249 250 while ( (c = *src++) ) { 251 again: 252 switch (unvis(dst, c, &state, 0)) { 253 case UNVIS_VALID: 254 dst++; 255 break; 256 case UNVIS_VALIDPUSH: 257 dst++; 258 goto again; 259 case 0: 260 case UNVIS_NOCHAR: 261 break; 262 default: 263 return (-1); 264 } 265 } 266 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID) 267 dst++; 268 *dst = '\0'; 269 return (dst - start); 270 } 271 272 int 273 strunvisx(dst, src, flag) 274 char *dst; 275 const char *src; 276 { 277 char c; 278 char *start = dst; 279 int state = 0; 280 281 while ( (c = *src++) ) { 282 again: 283 switch (unvis(dst, c, &state, flag)) { 284 case UNVIS_VALID: 285 dst++; 286 break; 287 case UNVIS_VALIDPUSH: 288 dst++; 289 goto again; 290 case 0: 291 case UNVIS_NOCHAR: 292 break; 293 default: 294 return (-1); 295 } 296 } 297 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID) 298 dst++; 299 *dst = '\0'; 300 return (dst - start); 301 } 302