1 /* $OpenBSD: vis.c,v 1.22 2011/03/13 22:21:32 guenther 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,flag) \ 39 (((c) == '\\' || (flag & VIS_ALL) == 0) && \ 40 (((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) && \ 41 (((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') || \ 42 (flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) || \ 43 ((flag & VIS_SP) == 0 && (c) == ' ') || \ 44 ((flag & VIS_TAB) == 0 && (c) == '\t') || \ 45 ((flag & VIS_NL) == 0 && (c) == '\n') || \ 46 ((flag & VIS_SAFE) && ((c) == '\b' || \ 47 (c) == '\007' || (c) == '\r' || \ 48 isgraph((u_char)(c)))))) 49 50 /* 51 * vis - visually encode characters 52 */ 53 char * 54 vis(char *dst, int c, int flag, int nextc) 55 { 56 if (isvisible(c, flag)) { 57 *dst++ = c; 58 if (c == '\\' && (flag & VIS_NOSLASH) == 0) 59 *dst++ = '\\'; 60 *dst = '\0'; 61 return (dst); 62 } 63 64 if (flag & VIS_CSTYLE) { 65 switch(c) { 66 case '\n': 67 *dst++ = '\\'; 68 *dst++ = 'n'; 69 goto done; 70 case '\r': 71 *dst++ = '\\'; 72 *dst++ = 'r'; 73 goto done; 74 case '\b': 75 *dst++ = '\\'; 76 *dst++ = 'b'; 77 goto done; 78 case '\a': 79 *dst++ = '\\'; 80 *dst++ = 'a'; 81 goto done; 82 case '\v': 83 *dst++ = '\\'; 84 *dst++ = 'v'; 85 goto done; 86 case '\t': 87 *dst++ = '\\'; 88 *dst++ = 't'; 89 goto done; 90 case '\f': 91 *dst++ = '\\'; 92 *dst++ = 'f'; 93 goto done; 94 case ' ': 95 *dst++ = '\\'; 96 *dst++ = 's'; 97 goto done; 98 case '\0': 99 *dst++ = '\\'; 100 *dst++ = '0'; 101 if (isoctal(nextc)) { 102 *dst++ = '0'; 103 *dst++ = '0'; 104 } 105 goto done; 106 } 107 } 108 if (((c & 0177) == ' ') || (flag & VIS_OCTAL) || 109 ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) { 110 *dst++ = '\\'; 111 *dst++ = ((u_char)c >> 6 & 07) + '0'; 112 *dst++ = ((u_char)c >> 3 & 07) + '0'; 113 *dst++ = ((u_char)c & 07) + '0'; 114 goto done; 115 } 116 if ((flag & VIS_NOSLASH) == 0) 117 *dst++ = '\\'; 118 if (c & 0200) { 119 c &= 0177; 120 *dst++ = 'M'; 121 } 122 if (iscntrl((u_char)c)) { 123 *dst++ = '^'; 124 if (c == 0177) 125 *dst++ = '?'; 126 else 127 *dst++ = c + '@'; 128 } else { 129 *dst++ = '-'; 130 *dst++ = c; 131 } 132 done: 133 *dst = '\0'; 134 return (dst); 135 } 136 137 /* 138 * strvis, strnvis, strvisx - visually encode characters from src into dst 139 * 140 * Dst must be 4 times the size of src to account for possible 141 * expansion. The length of dst, not including the trailing NULL, 142 * is returned. 143 * 144 * Strnvis will write no more than siz-1 bytes (and will NULL terminate). 145 * The number of bytes needed to fully encode the string is returned. 146 * 147 * Strvisx encodes exactly len bytes from src into dst. 148 * This is useful for encoding a block of data. 149 */ 150 int 151 strvis(char *dst, const char *src, int flag) 152 { 153 char c; 154 char *start; 155 156 for (start = dst; (c = *src);) 157 dst = vis(dst, c, flag, *++src); 158 *dst = '\0'; 159 return (dst - start); 160 } 161 162 int 163 strnvis(char *dst, const char *src, size_t siz, int flag) 164 { 165 char *start, *end; 166 char tbuf[5]; 167 int c, i; 168 169 i = 0; 170 for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) { 171 if (isvisible(c, flag)) { 172 i = 1; 173 *dst++ = c; 174 if (c == '\\' && (flag & VIS_NOSLASH) == 0) { 175 /* need space for the extra '\\' */ 176 if (dst < end) 177 *dst++ = '\\'; 178 else { 179 dst--; 180 i = 2; 181 break; 182 } 183 } 184 src++; 185 } else { 186 i = vis(tbuf, c, flag, *++src) - tbuf; 187 if (dst + i <= end) { 188 memcpy(dst, tbuf, i); 189 dst += i; 190 } else { 191 src--; 192 break; 193 } 194 } 195 } 196 if (siz > 0) 197 *dst = '\0'; 198 if (dst + i > end) { 199 /* adjust return value for truncation */ 200 while ((c = *src)) 201 dst += vis(tbuf, c, flag, *++src) - tbuf; 202 } 203 return (dst - start); 204 } 205 206 int 207 strvisx(char *dst, const char *src, size_t len, int flag) 208 { 209 char c; 210 char *start; 211 212 for (start = dst; len > 1; len--) { 213 c = *src; 214 dst = vis(dst, c, flag, *++src); 215 } 216 if (len) 217 dst = vis(dst, *src, flag, '\0'); 218 *dst = '\0'; 219 return (dst - start); 220 } 221