1 /* $OpenBSD: vis.c,v 1.19 2005/09/01 17:15:49 millert Exp $ */ 2 /*- 3 * Copyright (c) 1989, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/types.h> 32 #include <limits.h> 33 #include <ctype.h> 34 #include <string.h> 35 #include <vis.h> 36 37 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7') 38 #define isvisible(c) \ 39 (((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) && \ 40 (((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') || \ 41 (flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) || \ 42 ((flag & VIS_SP) == 0 && (c) == ' ') || \ 43 ((flag & VIS_TAB) == 0 && (c) == '\t') || \ 44 ((flag & VIS_NL) == 0 && (c) == '\n') || \ 45 ((flag & VIS_SAFE) && ((c) == '\b' || \ 46 (c) == '\007' || (c) == '\r' || \ 47 isgraph((u_char)(c))))) 48 49 /* 50 * vis - visually encode characters 51 */ 52 char * 53 vis(char *dst, int c, int flag, int nextc) 54 { 55 if (isvisible(c)) { 56 *dst++ = c; 57 if (c == '\\' && (flag & VIS_NOSLASH) == 0) 58 *dst++ = '\\'; 59 *dst = '\0'; 60 return (dst); 61 } 62 63 if (flag & VIS_CSTYLE) { 64 switch(c) { 65 case '\n': 66 *dst++ = '\\'; 67 *dst++ = 'n'; 68 goto done; 69 case '\r': 70 *dst++ = '\\'; 71 *dst++ = 'r'; 72 goto done; 73 case '\b': 74 *dst++ = '\\'; 75 *dst++ = 'b'; 76 goto done; 77 case '\a': 78 *dst++ = '\\'; 79 *dst++ = 'a'; 80 goto done; 81 case '\v': 82 *dst++ = '\\'; 83 *dst++ = 'v'; 84 goto done; 85 case '\t': 86 *dst++ = '\\'; 87 *dst++ = 't'; 88 goto done; 89 case '\f': 90 *dst++ = '\\'; 91 *dst++ = 'f'; 92 goto done; 93 case ' ': 94 *dst++ = '\\'; 95 *dst++ = 's'; 96 goto done; 97 case '\0': 98 *dst++ = '\\'; 99 *dst++ = '0'; 100 if (isoctal(nextc)) { 101 *dst++ = '0'; 102 *dst++ = '0'; 103 } 104 goto done; 105 } 106 } 107 if (((c & 0177) == ' ') || (flag & VIS_OCTAL) || 108 ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) { 109 *dst++ = '\\'; 110 *dst++ = ((u_char)c >> 6 & 07) + '0'; 111 *dst++ = ((u_char)c >> 3 & 07) + '0'; 112 *dst++ = ((u_char)c & 07) + '0'; 113 goto done; 114 } 115 if ((flag & VIS_NOSLASH) == 0) 116 *dst++ = '\\'; 117 if (c & 0200) { 118 c &= 0177; 119 *dst++ = 'M'; 120 } 121 if (iscntrl((u_char)c)) { 122 *dst++ = '^'; 123 if (c == 0177) 124 *dst++ = '?'; 125 else 126 *dst++ = c + '@'; 127 } else { 128 *dst++ = '-'; 129 *dst++ = c; 130 } 131 done: 132 *dst = '\0'; 133 return (dst); 134 } 135 136 /* 137 * strvis, strnvis, strvisx - visually encode characters from src into dst 138 * 139 * Dst must be 4 times the size of src to account for possible 140 * expansion. The length of dst, not including the trailing NULL, 141 * is returned. 142 * 143 * Strnvis will write no more than siz-1 bytes (and will NULL terminate). 144 * The number of bytes needed to fully encode the string is returned. 145 * 146 * Strvisx encodes exactly len bytes from src into dst. 147 * This is useful for encoding a block of data. 148 */ 149 int 150 strvis(char *dst, const char *src, int flag) 151 { 152 char c; 153 char *start; 154 155 for (start = dst; (c = *src);) 156 dst = vis(dst, c, flag, *++src); 157 *dst = '\0'; 158 return (dst - start); 159 } 160 161 int 162 strnvis(char *dst, const char *src, size_t siz, int flag) 163 { 164 char *start, *end; 165 char tbuf[5]; 166 int c, i; 167 168 i = 0; 169 for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) { 170 if (isvisible(c)) { 171 i = 1; 172 *dst++ = c; 173 if (c == '\\' && (flag & VIS_NOSLASH) == 0) { 174 /* need space for the extra '\\' */ 175 if (dst < end) 176 *dst++ = '\\'; 177 else { 178 dst--; 179 i = 2; 180 break; 181 } 182 } 183 src++; 184 } else { 185 i = vis(tbuf, c, flag, *++src) - tbuf; 186 if (dst + i <= end) { 187 memcpy(dst, tbuf, i); 188 dst += i; 189 } else { 190 src--; 191 break; 192 } 193 } 194 } 195 if (siz > 0) 196 *dst = '\0'; 197 if (dst + i > end) { 198 /* adjust return value for truncation */ 199 while ((c = *src)) 200 dst += vis(tbuf, c, flag, *++src) - tbuf; 201 } 202 return (dst - start); 203 } 204 205 int 206 strvisx(char *dst, const char *src, size_t len, int flag) 207 { 208 char c; 209 char *start; 210 211 for (start = dst; len > 1; len--) { 212 c = *src; 213 dst = vis(dst, c, flag, *++src); 214 } 215 if (len) 216 dst = vis(dst, *src, flag, '\0'); 217 *dst = '\0'; 218 return (dst - start); 219 } 220