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 1.5 2005/11/19 22:32:53 swildner Exp $ 35 * 36 * @(#)unvis.c 8.1 (Berkeley) 6/4/93 37 */ 38 39 #include <sys/types.h> 40 #include <ctype.h> 41 #include <vis.h> 42 43 /* 44 * decode driven by state machine 45 */ 46 #define S_GROUND 0 /* haven't seen escape char */ 47 #define S_START 1 /* start decoding special sequence */ 48 #define S_META 2 /* metachar started (M) */ 49 #define S_META1 3 /* metachar more, regular char (-) */ 50 #define S_CTRL 4 /* control char started (^) */ 51 #define S_OCTAL2 5 /* octal digit 2 */ 52 #define S_OCTAL3 6 /* octal digit 3 */ 53 #define S_HEX2 7 /* hex digit 2 */ 54 55 #define S_HTTP 0x080 /* %HEXHEX escape */ 56 57 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7') 58 #define ishex(c) ((((u_char)(c)) >= '0' && ((u_char)(c)) <= '9') || (((u_char)(c)) >= 'a' && ((u_char)(c)) <= 'f')) 59 60 /* 61 * unvis - decode characters previously encoded by vis 62 */ 63 int 64 unvis(char *cp, int c, int *astate, int flag) 65 { 66 67 if (flag & UNVIS_END) { 68 if (*astate == S_OCTAL2 || *astate == S_OCTAL3) { 69 *astate = S_GROUND; 70 return (UNVIS_VALID); 71 } 72 return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD); 73 } 74 75 switch (*astate & ~S_HTTP) { 76 77 case S_GROUND: 78 *cp = 0; 79 if (c == '\\') { 80 *astate = S_START; 81 return (0); 82 } 83 if (flag & VIS_HTTPSTYLE && c == '%') { 84 *astate = S_START | S_HTTP; 85 return (0); 86 } 87 *cp = c; 88 return (UNVIS_VALID); 89 90 case S_START: 91 if (*astate & S_HTTP) { 92 if (ishex(tolower(c))) { 93 *cp = isdigit(c) ? (c - '0') : (tolower(c) - 'a'); 94 *astate = S_HEX2; 95 return (0); 96 } 97 } 98 switch(c) { 99 case '\\': 100 *cp = c; 101 *astate = S_GROUND; 102 return (UNVIS_VALID); 103 case '0': case '1': case '2': case '3': 104 case '4': case '5': case '6': case '7': 105 *cp = (c - '0'); 106 *astate = S_OCTAL2; 107 return (0); 108 case 'M': 109 *cp = (char)0200; 110 *astate = S_META; 111 return (0); 112 case '^': 113 *astate = S_CTRL; 114 return (0); 115 case 'n': 116 *cp = '\n'; 117 *astate = S_GROUND; 118 return (UNVIS_VALID); 119 case 'r': 120 *cp = '\r'; 121 *astate = S_GROUND; 122 return (UNVIS_VALID); 123 case 'b': 124 *cp = '\b'; 125 *astate = S_GROUND; 126 return (UNVIS_VALID); 127 case 'a': 128 *cp = '\007'; 129 *astate = S_GROUND; 130 return (UNVIS_VALID); 131 case 'v': 132 *cp = '\v'; 133 *astate = S_GROUND; 134 return (UNVIS_VALID); 135 case 't': 136 *cp = '\t'; 137 *astate = S_GROUND; 138 return (UNVIS_VALID); 139 case 'f': 140 *cp = '\f'; 141 *astate = S_GROUND; 142 return (UNVIS_VALID); 143 case 's': 144 *cp = ' '; 145 *astate = S_GROUND; 146 return (UNVIS_VALID); 147 case 'E': 148 *cp = '\033'; 149 *astate = S_GROUND; 150 return (UNVIS_VALID); 151 case '\n': 152 /* 153 * hidden newline 154 */ 155 *astate = S_GROUND; 156 return (UNVIS_NOCHAR); 157 case '$': 158 /* 159 * hidden marker 160 */ 161 *astate = S_GROUND; 162 return (UNVIS_NOCHAR); 163 } 164 *astate = S_GROUND; 165 return (UNVIS_SYNBAD); 166 167 case S_META: 168 if (c == '-') 169 *astate = S_META1; 170 else if (c == '^') 171 *astate = S_CTRL; 172 else { 173 *astate = S_GROUND; 174 return (UNVIS_SYNBAD); 175 } 176 return (0); 177 178 case S_META1: 179 *astate = S_GROUND; 180 *cp |= c; 181 return (UNVIS_VALID); 182 183 case S_CTRL: 184 if (c == '?') 185 *cp |= 0177; 186 else 187 *cp |= c & 037; 188 *astate = S_GROUND; 189 return (UNVIS_VALID); 190 191 case S_OCTAL2: /* second possible octal digit */ 192 if (isoctal(c)) { 193 /* 194 * yes - and maybe a third 195 */ 196 *cp = (*cp << 3) + (c - '0'); 197 *astate = S_OCTAL3; 198 return (0); 199 } 200 /* 201 * no - done with current sequence, push back passed char 202 */ 203 *astate = S_GROUND; 204 return (UNVIS_VALIDPUSH); 205 206 case S_OCTAL3: /* third possible octal digit */ 207 *astate = S_GROUND; 208 if (isoctal(c)) { 209 *cp = (*cp << 3) + (c - '0'); 210 return (UNVIS_VALID); 211 } 212 /* 213 * we were done, push back passed char 214 */ 215 return (UNVIS_VALIDPUSH); 216 217 case S_HEX2: /* second mandatory hex digit */ 218 if (ishex(tolower(c))) { 219 *cp = (isdigit(c) ? (*cp << 4) + (c - '0') : (*cp << 4) + (tolower(c) - 'a' + 10)); 220 } 221 *astate = S_GROUND; 222 return (UNVIS_VALID); 223 224 default: 225 /* 226 * decoder in unknown state - (probably uninitialized) 227 */ 228 *astate = S_GROUND; 229 return (UNVIS_SYNBAD); 230 } 231 } 232 233 /* 234 * strunvis - decode src into dst 235 * 236 * Number of chars decoded into dst is returned, -1 on error. 237 * Dst is null terminated. 238 */ 239 240 int 241 strunvis(char *dst, const char *src) 242 { 243 char c; 244 char *start = dst; 245 int state = 0; 246 247 while ( (c = *src++) ) { 248 again: 249 switch (unvis(dst, c, &state, 0)) { 250 case UNVIS_VALID: 251 dst++; 252 break; 253 case UNVIS_VALIDPUSH: 254 dst++; 255 goto again; 256 case 0: 257 case UNVIS_NOCHAR: 258 break; 259 default: 260 return (-1); 261 } 262 } 263 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID) 264 dst++; 265 *dst = '\0'; 266 return (dst - start); 267 } 268 269 int 270 strunvisx(char *dst, const char *src, int flag) 271 { 272 char c; 273 char *start = dst; 274 int state = 0; 275 276 while ( (c = *src++) ) { 277 again: 278 switch (unvis(dst, c, &state, flag)) { 279 case UNVIS_VALID: 280 dst++; 281 break; 282 case UNVIS_VALIDPUSH: 283 dst++; 284 goto again; 285 case 0: 286 case UNVIS_NOCHAR: 287 break; 288 default: 289 return (-1); 290 } 291 } 292 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID) 293 dst++; 294 *dst = '\0'; 295 return (dst - start); 296 } 297