unvis.c revision 1.2
1 /*- 2 * Copyright (c) 1989 The Regents of the University of California. 3 * 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 34 #if defined(LIBC_SCCS) && !defined(lint) 35 /*static char sccsid[] = "from: @(#)unvis.c 1.4 (Berkeley) 2/23/91";*/ 36 static char rcsid[] = "$Id: unvis.c,v 1.2 1993/07/30 08:23:55 mycroft Exp $"; 37 #endif /* LIBC_SCCS and not lint */ 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 54 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7') 55 56 /* 57 * unvis - decode characters previously encoded by vis 58 */ 59 int 60 #if __STDC__ 61 unvis(char *cp, char c, int *astate, int flag) 62 #else 63 unvis(cp, c, astate, flag) 64 char *cp, c; 65 int *astate, flag; 66 #endif 67 { 68 69 if (flag & UNVIS_END) { 70 if (*astate == S_OCTAL2 || *astate == S_OCTAL3) { 71 *astate = S_GROUND; 72 return (UNVIS_VALID); 73 } 74 return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD); 75 } 76 77 switch (*astate) { 78 79 case S_GROUND: 80 *cp = 0; 81 if (c == '\\') { 82 *astate = S_START; 83 return (0); 84 } 85 *cp = c; 86 return (UNVIS_VALID); 87 88 case S_START: 89 switch(c) { 90 case '\\': 91 *cp = c; 92 *astate = S_GROUND; 93 return (UNVIS_VALID); 94 case '0': case '1': case '2': case '3': 95 case '4': case '5': case '6': case '7': 96 *cp = (c - '0'); 97 *astate = S_OCTAL2; 98 return (0); 99 case 'M': 100 *cp = 0200; 101 *astate = S_META; 102 return (0); 103 case '^': 104 *astate = S_CTRL; 105 return (0); 106 case 'n': 107 *cp = '\n'; 108 *astate = S_GROUND; 109 return (UNVIS_VALID); 110 case 'r': 111 *cp = '\r'; 112 *astate = S_GROUND; 113 return (UNVIS_VALID); 114 case 'b': 115 *cp = '\b'; 116 *astate = S_GROUND; 117 return (UNVIS_VALID); 118 case 'a': 119 *cp = '\007'; 120 *astate = S_GROUND; 121 return (UNVIS_VALID); 122 case 'v': 123 *cp = '\v'; 124 *astate = S_GROUND; 125 return (UNVIS_VALID); 126 case 't': 127 *cp = '\t'; 128 *astate = S_GROUND; 129 return (UNVIS_VALID); 130 case 'f': 131 *cp = '\f'; 132 *astate = S_GROUND; 133 return (UNVIS_VALID); 134 case 's': 135 *cp = ' '; 136 *astate = S_GROUND; 137 return (UNVIS_VALID); 138 case 'E': 139 *cp = '\033'; 140 *astate = S_GROUND; 141 return (UNVIS_VALID); 142 case '\n': 143 /* 144 * hidden newline 145 */ 146 *astate = S_GROUND; 147 return (UNVIS_NOCHAR); 148 case '$': 149 /* 150 * hidden marker 151 */ 152 *astate = S_GROUND; 153 return (UNVIS_NOCHAR); 154 } 155 *astate = S_GROUND; 156 return (UNVIS_SYNBAD); 157 158 case S_META: 159 if (c == '-') 160 *astate = S_META1; 161 else if (c == '^') 162 *astate = S_CTRL; 163 else { 164 *astate = S_GROUND; 165 return (UNVIS_SYNBAD); 166 } 167 return (0); 168 169 case S_META1: 170 *astate = S_GROUND; 171 *cp |= c; 172 return (UNVIS_VALID); 173 174 case S_CTRL: 175 if (c == '?') 176 *cp |= 0177; 177 else 178 *cp |= c & 037; 179 *astate = S_GROUND; 180 return (UNVIS_VALID); 181 182 case S_OCTAL2: /* second possible octal digit */ 183 if (isoctal(c)) { 184 /* 185 * yes - and maybe a third 186 */ 187 *cp = (*cp << 3) + (c - '0'); 188 *astate = S_OCTAL3; 189 return (0); 190 } 191 /* 192 * no - done with current sequence, push back passed char 193 */ 194 *astate = S_GROUND; 195 return (UNVIS_VALIDPUSH); 196 197 case S_OCTAL3: /* third possible octal digit */ 198 *astate = S_GROUND; 199 if (isoctal(c)) { 200 *cp = (*cp << 3) + (c - '0'); 201 return (UNVIS_VALID); 202 } 203 /* 204 * we were done, push back passed char 205 */ 206 return (UNVIS_VALIDPUSH); 207 208 default: 209 /* 210 * decoder in unknown state - (probably uninitialized) 211 */ 212 *astate = S_GROUND; 213 return (UNVIS_SYNBAD); 214 } 215 } 216 217 /* 218 * strunvis - decode src into dst 219 * 220 * Number of chars decoded into dst is returned, -1 on error. 221 * Dst is null terminated. 222 */ 223 224 int 225 strunvis(dst, src) 226 register char *dst; 227 register const char *src; 228 { 229 register char c; 230 char *start = dst; 231 int state = 0; 232 233 while (c = *src++) { 234 again: 235 switch (unvis(dst, c, &state, 0)) { 236 case UNVIS_VALID: 237 dst++; 238 break; 239 case UNVIS_VALIDPUSH: 240 dst++; 241 goto again; 242 case 0: 243 case UNVIS_NOCHAR: 244 break; 245 default: 246 return (-1); 247 } 248 } 249 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID) 250 dst++; 251 *dst = '\0'; 252 return (dst - start); 253 } 254
Indexes created Tue Sep 30 10:09:55 GMT 2025