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 <stand.h> 18 #include <string.h> 19 #include "bootstrap.h" 20 21 #define DIGIT(x) (isdigit(x) ? (x) - '0' : islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A') 22 23 /* 24 * backslash: Return malloc'd copy of str with all standard "backslash 25 * processing" done on it. Original can be free'd if desired. 26 */ 27 char * 28 backslash(const char *str) 29 { 30 /* 31 * Remove backslashes from the strings. Turn \040 etc. into a single 32 * character (we allow eight bit values). Currently NUL is not 33 * allowed. 34 * 35 * Turn "\n" and "\t" into '\n' and '\t' characters. Etc. 36 * 37 */ 38 char *new_str; 39 int seenbs = 0; 40 int i = 0; 41 42 if ((new_str = strdup(str)) == NULL) 43 return NULL; 44 45 while (*str) { 46 if (seenbs) { 47 seenbs = 0; 48 switch (*str) { 49 case '\\': 50 new_str[i++] = '\\'; 51 str++; 52 break; 53 54 /* preserve backslashed quotes, dollar signs */ 55 case '\'': 56 case '"': 57 case '$': 58 new_str[i++] = '\\'; 59 new_str[i++] = *str++; 60 break; 61 62 case 'b': 63 new_str[i++] = '\b'; 64 str++; 65 break; 66 67 case 'f': 68 new_str[i++] = '\f'; 69 str++; 70 break; 71 72 case 'r': 73 new_str[i++] = '\r'; 74 str++; 75 break; 76 77 case 'n': 78 new_str[i++] = '\n'; 79 str++; 80 break; 81 82 case 's': 83 new_str[i++] = ' '; 84 str++; 85 break; 86 87 case 't': 88 new_str[i++] = '\t'; 89 str++; 90 break; 91 92 case 'v': 93 new_str[i++] = '\13'; 94 str++; 95 break; 96 97 case 'z': 98 str++; 99 break; 100 101 case '0': case '1': case '2': case '3': case '4': 102 case '5': case '6': case '7': case '8': case '9': { 103 char val; 104 105 /* Three digit octal constant? */ 106 if (*str >= '0' && *str <= '3' && 107 *(str + 1) >= '0' && *(str + 1) <= '7' && 108 *(str + 2) >= '0' && *(str + 2) <= '7') { 109 110 val = (DIGIT(*str) << 6) + (DIGIT(*(str + 1)) << 3) + 111 DIGIT(*(str + 2)); 112 113 /* Allow null value if user really wants to shoot 114 at feet, but beware! */ 115 new_str[i++] = val; 116 str += 3; 117 break; 118 } 119 120 /* One or two digit hex constant? 121 * If two are there they will both be taken. 122 * Use \z to split them up if this is not wanted. 123 */ 124 if (*str == '0' && 125 (*(str + 1) == 'x' || *(str + 1) == 'X') && 126 isxdigit(*(str + 2))) { 127 val = DIGIT(*(str + 2)); 128 if (isxdigit(*(str + 3))) { 129 val = (val << 4) + DIGIT(*(str + 3)); 130 str += 4; 131 } 132 else 133 str += 3; 134 /* Yep, allow null value here too */ 135 new_str[i++] = val; 136 break; 137 } 138 } 139 break; 140 141 default: 142 new_str[i++] = *str++; 143 break; 144 } 145 } 146 else { 147 if (*str == '\\') { 148 seenbs = 1; 149 str++; 150 } 151 else 152 new_str[i++] = *str++; 153 } 154 } 155 156 if (seenbs) { 157 /* 158 * The final character was a '\'. Put it in as a single backslash. 159 */ 160 new_str[i++] = '\\'; 161 } 162 new_str[i] = '\0'; 163 return new_str; 164 } 165