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. 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 * $FreeBSD: src/lib/libc/gen/unvis.c,v 1.4.8.1 2000/08/17 08:25:54 jhb Exp $ 30 * $DragonFly: src/lib/libc/gen/unvis.c,v 1.5 2005/11/19 22:32:53 swildner Exp $ 31 * 32 * @(#)unvis.c 8.1 (Berkeley) 6/4/93 33 */ 34 35 #include <sys/types.h> 36 #include <ctype.h> 37 #include <vis.h> 38 39 /* 40 * decode driven by state machine 41 */ 42 #define S_GROUND 0 /* haven't seen escape char */ 43 #define S_START 1 /* start decoding special sequence */ 44 #define S_META 2 /* metachar started (M) */ 45 #define S_META1 3 /* metachar more, regular char (-) */ 46 #define S_CTRL 4 /* control char started (^) */ 47 #define S_OCTAL2 5 /* octal digit 2 */ 48 #define S_OCTAL3 6 /* octal digit 3 */ 49 #define S_HEX2 7 /* hex digit 2 */ 50 51 #define S_HTTP 0x080 /* %HEXHEX escape */ 52 53 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7') 54 #define ishex(c) ((((u_char)(c)) >= '0' && ((u_char)(c)) <= '9') || (((u_char)(c)) >= 'a' && ((u_char)(c)) <= 'f')) 55 56 /* 57 * unvis - decode characters previously encoded by vis 58 */ 59 int 60 unvis(char *cp, int c, int *astate, int flag) 61 { 62 63 if (flag & UNVIS_END) { 64 if (*astate == S_OCTAL2 || *astate == S_OCTAL3) { 65 *astate = S_GROUND; 66 return (UNVIS_VALID); 67 } 68 return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD); 69 } 70 71 switch (*astate & ~S_HTTP) { 72 73 case S_GROUND: 74 *cp = 0; 75 if (c == '\\') { 76 *astate = S_START; 77 return (0); 78 } 79 if (flag & VIS_HTTPSTYLE && c == '%') { 80 *astate = S_START | S_HTTP; 81 return (0); 82 } 83 *cp = c; 84 return (UNVIS_VALID); 85 86 case S_START: 87 if (*astate & S_HTTP) { 88 if (ishex(tolower(c))) { 89 *cp = isdigit(c) ? (c - '0') : (tolower(c) - 'a'); 90 *astate = S_HEX2; 91 return (0); 92 } 93 } 94 switch(c) { 95 case '\\': 96 *cp = c; 97 *astate = S_GROUND; 98 return (UNVIS_VALID); 99 case '0': case '1': case '2': case '3': 100 case '4': case '5': case '6': case '7': 101 *cp = (c - '0'); 102 *astate = S_OCTAL2; 103 return (0); 104 case 'M': 105 *cp = (char)0200; 106 *astate = S_META; 107 return (0); 108 case '^': 109 *astate = S_CTRL; 110 return (0); 111 case 'n': 112 *cp = '\n'; 113 *astate = S_GROUND; 114 return (UNVIS_VALID); 115 case 'r': 116 *cp = '\r'; 117 *astate = S_GROUND; 118 return (UNVIS_VALID); 119 case 'b': 120 *cp = '\b'; 121 *astate = S_GROUND; 122 return (UNVIS_VALID); 123 case 'a': 124 *cp = '\007'; 125 *astate = S_GROUND; 126 return (UNVIS_VALID); 127 case 'v': 128 *cp = '\v'; 129 *astate = S_GROUND; 130 return (UNVIS_VALID); 131 case 't': 132 *cp = '\t'; 133 *astate = S_GROUND; 134 return (UNVIS_VALID); 135 case 'f': 136 *cp = '\f'; 137 *astate = S_GROUND; 138 return (UNVIS_VALID); 139 case 's': 140 *cp = ' '; 141 *astate = S_GROUND; 142 return (UNVIS_VALID); 143 case 'E': 144 *cp = '\033'; 145 *astate = S_GROUND; 146 return (UNVIS_VALID); 147 case '\n': 148 /* 149 * hidden newline 150 */ 151 *astate = S_GROUND; 152 return (UNVIS_NOCHAR); 153 case '$': 154 /* 155 * hidden marker 156 */ 157 *astate = S_GROUND; 158 return (UNVIS_NOCHAR); 159 } 160 *astate = S_GROUND; 161 return (UNVIS_SYNBAD); 162 163 case S_META: 164 if (c == '-') 165 *astate = S_META1; 166 else if (c == '^') 167 *astate = S_CTRL; 168 else { 169 *astate = S_GROUND; 170 return (UNVIS_SYNBAD); 171 } 172 return (0); 173 174 case S_META1: 175 *astate = S_GROUND; 176 *cp |= c; 177 return (UNVIS_VALID); 178 179 case S_CTRL: 180 if (c == '?') 181 *cp |= 0177; 182 else 183 *cp |= c & 037; 184 *astate = S_GROUND; 185 return (UNVIS_VALID); 186 187 case S_OCTAL2: /* second possible octal digit */ 188 if (isoctal(c)) { 189 /* 190 * yes - and maybe a third 191 */ 192 *cp = (*cp << 3) + (c - '0'); 193 *astate = S_OCTAL3; 194 return (0); 195 } 196 /* 197 * no - done with current sequence, push back passed char 198 */ 199 *astate = S_GROUND; 200 return (UNVIS_VALIDPUSH); 201 202 case S_OCTAL3: /* third possible octal digit */ 203 *astate = S_GROUND; 204 if (isoctal(c)) { 205 *cp = (*cp << 3) + (c - '0'); 206 return (UNVIS_VALID); 207 } 208 /* 209 * we were done, push back passed char 210 */ 211 return (UNVIS_VALIDPUSH); 212 213 case S_HEX2: /* second mandatory hex digit */ 214 if (ishex(tolower(c))) { 215 *cp = (isdigit(c) ? (*cp << 4) + (c - '0') : (*cp << 4) + (tolower(c) - 'a' + 10)); 216 } 217 *astate = S_GROUND; 218 return (UNVIS_VALID); 219 220 default: 221 /* 222 * decoder in unknown state - (probably uninitialized) 223 */ 224 *astate = S_GROUND; 225 return (UNVIS_SYNBAD); 226 } 227 } 228 229 /* 230 * strunvis - decode src into dst 231 * 232 * Number of chars decoded into dst is returned, -1 on error. 233 * Dst is null terminated. 234 */ 235 236 int 237 strunvis(char *dst, const char *src) 238 { 239 char c; 240 char *start = dst; 241 int state = 0; 242 243 while ( (c = *src++) ) { 244 again: 245 switch (unvis(dst, c, &state, 0)) { 246 case UNVIS_VALID: 247 dst++; 248 break; 249 case UNVIS_VALIDPUSH: 250 dst++; 251 goto again; 252 case 0: 253 case UNVIS_NOCHAR: 254 break; 255 default: 256 return (-1); 257 } 258 } 259 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID) 260 dst++; 261 *dst = '\0'; 262 return (dst - start); 263 } 264 265 int 266 strunvisx(char *dst, const char *src, int flag) 267 { 268 char c; 269 char *start = dst; 270 int state = 0; 271 272 while ( (c = *src++) ) { 273 again: 274 switch (unvis(dst, c, &state, flag)) { 275 case UNVIS_VALID: 276 dst++; 277 break; 278 case UNVIS_VALIDPUSH: 279 dst++; 280 goto again; 281 case 0: 282 case UNVIS_NOCHAR: 283 break; 284 default: 285 return (-1); 286 } 287 } 288 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID) 289 dst++; 290 *dst = '\0'; 291 return (dst - start); 292 } 293