unvis.c revision 1.1
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[] = "@(#)unvis.c 1.4 (Berkeley) 2/23/91"; 36 #endif /* LIBC_SCCS and not lint */ 37 38 #include <sys/types.h> 39 #include <ctype.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 53 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7') 54 55 /* 56 * unvis - decode characters previously encoded by vis 57 */ 58 int 59 #if __STDC__ 60 unvis(char *cp, char c, int *astate, int flag) 61 #else 62 unvis(cp, c, astate, flag) 63 char *cp, c; 64 int *astate, flag; 65 #endif 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) { 77 78 case S_GROUND: 79 *cp = 0; 80 if (c == '\\') { 81 *astate = S_START; 82 return (0); 83 } 84 *cp = c; 85 return (UNVIS_VALID); 86 87 case S_START: 88 switch(c) { 89 case '\\': 90 *cp = c; 91 *astate = S_GROUND; 92 return (UNVIS_VALID); 93 case '0': case '1': case '2': case '3': 94 case '4': case '5': case '6': case '7': 95 *cp = (c - '0'); 96 *astate = S_OCTAL2; 97 return (0); 98 case 'M': 99 *cp = 0200; 100 *astate = S_META; 101 return (0); 102 case '^': 103 *astate = S_CTRL; 104 return (0); 105 case 'n': 106 *cp = '\n'; 107 *astate = S_GROUND; 108 return (UNVIS_VALID); 109 case 'r': 110 *cp = '\r'; 111 *astate = S_GROUND; 112 return (UNVIS_VALID); 113 case 'b': 114 *cp = '\b'; 115 *astate = S_GROUND; 116 return (UNVIS_VALID); 117 case 'a': 118 *cp = '\007'; 119 *astate = S_GROUND; 120 return (UNVIS_VALID); 121 case 'v': 122 *cp = '\v'; 123 *astate = S_GROUND; 124 return (UNVIS_VALID); 125 case 't': 126 *cp = '\t'; 127 *astate = S_GROUND; 128 return (UNVIS_VALID); 129 case 'f': 130 *cp = '\f'; 131 *astate = S_GROUND; 132 return (UNVIS_VALID); 133 case 's': 134 *cp = ' '; 135 *astate = S_GROUND; 136 return (UNVIS_VALID); 137 case 'E': 138 *cp = '\033'; 139 *astate = S_GROUND; 140 return (UNVIS_VALID); 141 case '\n': 142 /* 143 * hidden newline 144 */ 145 *astate = S_GROUND; 146 return (UNVIS_NOCHAR); 147 case '$': 148 /* 149 * hidden marker 150 */ 151 *astate = S_GROUND; 152 return (UNVIS_NOCHAR); 153 } 154 *astate = S_GROUND; 155 return (UNVIS_SYNBAD); 156 157 case S_META: 158 if (c == '-') 159 *astate = S_META1; 160 else if (c == '^') 161 *astate = S_CTRL; 162 else { 163 *astate = S_GROUND; 164 return (UNVIS_SYNBAD); 165 } 166 return (0); 167 168 case S_META1: 169 *astate = S_GROUND; 170 *cp |= c; 171 return (UNVIS_VALID); 172 173 case S_CTRL: 174 if (c == '?') 175 *cp |= 0177; 176 else 177 *cp |= c & 037; 178 *astate = S_GROUND; 179 return (UNVIS_VALID); 180 181 case S_OCTAL2: /* second possible octal digit */ 182 if (isoctal(c)) { 183 /* 184 * yes - and maybe a third 185 */ 186 *cp = (*cp << 3) + (c - '0'); 187 *astate = S_OCTAL3; 188 return (0); 189 } 190 /* 191 * no - done with current sequence, push back passed char 192 */ 193 *astate = S_GROUND; 194 return (UNVIS_VALIDPUSH); 195 196 case S_OCTAL3: /* third possible octal digit */ 197 *astate = S_GROUND; 198 if (isoctal(c)) { 199 *cp = (*cp << 3) + (c - '0'); 200 return (UNVIS_VALID); 201 } 202 /* 203 * we were done, push back passed char 204 */ 205 return (UNVIS_VALIDPUSH); 206 207 default: 208 /* 209 * decoder in unknown state - (probably uninitialized) 210 */ 211 *astate = S_GROUND; 212 return (UNVIS_SYNBAD); 213 } 214 } 215 216 /* 217 * strunvis - decode src into dst 218 * 219 * Number of chars decoded into dst is returned, -1 on error. 220 * Dst is null terminated. 221 */ 222 223 int 224 strunvis(dst, src) 225 register char *dst; 226 register const char *src; 227 { 228 register char c; 229 char *start = dst; 230 int state = 0; 231 232 while (c = *src++) { 233 again: 234 switch (unvis(dst, c, &state, 0)) { 235 case UNVIS_VALID: 236 dst++; 237 break; 238 case UNVIS_VALIDPUSH: 239 dst++; 240 goto again; 241 case 0: 242 case UNVIS_NOCHAR: 243 break; 244 default: 245 return (-1); 246 } 247 } 248 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID) 249 dst++; 250 *dst = '\0'; 251 return (dst - start); 252 } 253
Indexes created Sun Sep 21 18:09:52 GMT 2025