1 /*- 2 * Redistribution and use in source and binary forms, with or without 3 * modification, are permitted provided that the following conditions 4 * are met: 5 * 1. Redistributions of source code must retain the above copyright 6 * notice, this list of conditions and the following disclaimer. 7 * 2. Redistributions in binary form must reproduce the above copyright 8 * notice, this list of conditions and the following disclaimer in the 9 * documentation and/or other materials provided with the distribution. 10 * 11 * Jordan K. Hubbard 12 * 29 August 1998 13 * 14 * Routine for doing backslash elimination. 15 */ 16 17 #include <sys/cdefs.h> 18 #include <stand.h> 19 #include <string.h> 20 #include "bootstrap.h" 21 22 #define DIGIT(x) (isdigit(x) ? (x) - '0' : islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A') 23 24 /* 25 * backslash: Return malloc'd copy of str with all standard "backslash 26 * processing" done on it. Original can be free'd if desired. 27 */ 28 char * 29 backslash(const char *str) 30 { 31 /* 32 * Remove backslashes from the strings. Turn \040 etc. into a single 33 * character (we allow eight bit values). Currently NUL is not 34 * allowed. 35 * 36 * Turn "\n" and "\t" into '\n' and '\t' characters. Etc. 37 * 38 */ 39 char *new_str; 40 int seenbs = 0; 41 int i = 0; 42 43 if ((new_str = strdup(str)) == NULL) 44 return NULL; 45 46 while (*str) { 47 if (seenbs) { 48 seenbs = 0; 49 switch (*str) { 50 case '\\': 51 new_str[i++] = '\\'; 52 str++; 53 break; 54 55 /* preserve backslashed quotes, dollar signs */ 56 case '\'': 57 case '"': 58 case '$': 59 new_str[i++] = '\\'; 60 new_str[i++] = *str++; 61 break; 62 63 case 'b': 64 new_str[i++] = '\b'; 65 str++; 66 break; 67 68 case 'f': 69 new_str[i++] = '\f'; 70 str++; 71 break; 72 73 case 'r': 74 new_str[i++] = '\r'; 75 str++; 76 break; 77 78 case 'n': 79 new_str[i++] = '\n'; 80 str++; 81 break; 82 83 case 's': 84 new_str[i++] = ' '; 85 str++; 86 break; 87 88 case 't': 89 new_str[i++] = '\t'; 90 str++; 91 break; 92 93 case 'v': 94 new_str[i++] = '\13'; 95 str++; 96 break; 97 98 case 'z': 99 str++; 100 break; 101 102 case '0': case '1': case '2': case '3': case '4': 103 case '5': case '6': case '7': case '8': case '9': { 104 char val; 105 106 /* Three digit octal constant? */ 107 if (*str >= '0' && *str <= '3' && 108 *(str + 1) >= '0' && *(str + 1) <= '7' && 109 *(str + 2) >= '0' && *(str + 2) <= '7') { 110 111 val = (DIGIT(*str) << 6) + (DIGIT(*(str + 1)) << 3) + 112 DIGIT(*(str + 2)); 113 114 /* Allow null value if user really wants to shoot 115 at feet, but beware! */ 116 new_str[i++] = val; 117 str += 3; 118 break; 119 } 120 121 /* One or two digit hex constant? 122 * If two are there they will both be taken. 123 * Use \z to split them up if this is not wanted. 124 */ 125 if (*str == '0' && 126 (*(str + 1) == 'x' || *(str + 1) == 'X') && 127 isxdigit(*(str + 2))) { 128 val = DIGIT(*(str + 2)); 129 if (isxdigit(*(str + 3))) { 130 val = (val << 4) + DIGIT(*(str + 3)); 131 str += 4; 132 } 133 else 134 str += 3; 135 /* Yep, allow null value here too */ 136 new_str[i++] = val; 137 break; 138 } 139 } 140 break; 141 142 default: 143 new_str[i++] = *str++; 144 break; 145 } 146 } 147 else { 148 if (*str == '\\') { 149 seenbs = 1; 150 str++; 151 } 152 else 153 new_str[i++] = *str++; 154 } 155 } 156 157 if (seenbs) { 158 /* 159 * The final character was a '\'. Put it in as a single backslash. 160 */ 161 new_str[i++] = '\\'; 162 } 163 new_str[i] = '\0'; 164 return new_str; 165 } 166