1 /*-
2 * Copyright (c) 2001-2014 Devin Teske <[email protected]>
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29
30 #include <sys/types.h>
31
32 #include <ctype.h>
33 #include <errno.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37
38 #include "string_m.h"
39
40 /*
41 * Counts the number of occurrences of one string that appear in the source
42 * string. Return value is the total count.
43 *
44 * An example use would be if you need to know how large a block of memory
45 * needs to be for a replaceall() series.
46 */
47 unsigned int
strcount(const char * source,const char * find)48 strcount(const char *source, const char *find)
49 {
50 const char *p = source;
51 size_t flen;
52 unsigned int n = 0;
53
54 /* Both parameters are required */
55 if (source == NULL || find == NULL)
56 return (0);
57
58 /* Cache the length of find element */
59 flen = strlen(find);
60 if (strlen(source) == 0 || flen == 0)
61 return (0);
62
63 /* Loop until the end of the string */
64 while (*p != '\0') {
65 if (strncmp(p, find, flen) == 0) { /* found an instance */
66 p += flen;
67 n++;
68 } else
69 p++;
70 }
71
72 return (n);
73 }
74
75 /*
76 * Replaces all occurrences of `find' in `source' with `replace'.
77 *
78 * You should not pass a string constant as the first parameter, it needs to be
79 * a pointer to an allocated block of memory. The block of memory that source
80 * points to should be large enough to hold the result. If the length of the
81 * replacement string is greater than the length of the find string, the result
82 * will be larger than the original source string. To allocate enough space for
83 * the result, use the function strcount() declared above to determine the
84 * number of occurrences and how much larger the block size needs to be.
85 *
86 * If source is not large enough, the application will crash. The return value
87 * is the length (in bytes) of the result.
88 *
89 * When an error occurs, -1 is returned and the global variable errno is set
90 * accordingly. Returns zero on success.
91 */
92 int
replaceall(char * source,const char * find,const char * replace)93 replaceall(char *source, const char *find, const char *replace)
94 {
95 char *p;
96 char *t;
97 char *temp;
98 size_t flen;
99 size_t rlen;
100 size_t slen;
101 uint32_t n = 0;
102
103 errno = 0; /* reset global error number */
104
105 /* Check that we have non-null parameters */
106 if (source == NULL)
107 return (0);
108 if (find == NULL)
109 return (strlen(source));
110
111 /* Cache the length of the strings */
112 slen = strlen(source);
113 flen = strlen(find);
114 rlen = replace ? strlen(replace) : 0;
115
116 /* Cases where no replacements need to be made */
117 if (slen == 0 || flen == 0 || slen < flen)
118 return (slen);
119
120 /* If replace is longer than find, we'll need to create a temp copy */
121 if (rlen > flen) {
122 temp = malloc(slen + 1);
123 if (temp == NULL) /* could not allocate memory */
124 return (-1);
125 memcpy(temp, source, slen + 1);
126 } else
127 temp = source;
128
129 /* Reconstruct the string with the replacements */
130 p = source; t = temp; /* position elements */
131
132 while (*t != '\0') {
133 if (strncmp(t, find, flen) == 0) {
134 /* found an occurrence */
135 for (n = 0; replace && replace[n]; n++)
136 *p++ = replace[n];
137 t += flen;
138 } else
139 *p++ = *t++; /* copy character and increment */
140 }
141
142 /* Terminate the string */
143 *p = '\0';
144
145 /* Free the temporary allocated memory */
146 if (temp != source)
147 free(temp);
148
149 /* Return the length of the completed string */
150 return (strlen(source));
151 }
152
153 /*
154 * Expands escape sequences in a buffer pointed to by `source'. This function
155 * steps through each character, and converts escape sequences such as "\n",
156 * "\r", "\t" and others into their respective meanings.
157 *
158 * You should not pass a string constant or literal to this function or the
159 * program will likely segmentation fault when it tries to modify the data.
160 *
161 * The string length will either shorten or stay the same depending on whether
162 * any escape sequences were converted but the amount of memory allocated does
163 * not change.
164 *
165 * Interpreted sequences are:
166 *
167 * \0NNN character with octal value NNN (0 to 3 digits)
168 * \N character with octal value N (0 thru 7)
169 * \a alert (BEL)
170 * \b backslash
171 * \f form feed
172 * \n new line
173 * \r carriage return
174 * \t horizontal tab
175 * \v vertical tab
176 * \xNN byte with hexadecimal value NN (1 to 2 digits)
177 *
178 * All other sequences are unescaped (ie. '\"' and '\#').
179 */
strexpand(char * source)180 void strexpand(char *source)
181 {
182 uint8_t c;
183 char *chr;
184 char *pos;
185 char d[4];
186
187 /* Initialize position elements */
188 pos = chr = source;
189
190 /* Loop until we hit the end of the string */
191 while (*pos != '\0') {
192 if (*chr != '\\') {
193 *pos = *chr; /* copy character to current offset */
194 pos++;
195 chr++;
196 continue;
197 }
198
199 /* Replace the backslash with the correct character */
200 switch (*++chr) {
201 case 'a': *pos = '\a'; break; /* bell/alert (BEL) */
202 case 'b': *pos = '\b'; break; /* backspace */
203 case 'f': *pos = '\f'; break; /* form feed */
204 case 'n': *pos = '\n'; break; /* new line */
205 case 'r': *pos = '\r'; break; /* carriage return */
206 case 't': *pos = '\t'; break; /* horizontal tab */
207 case 'v': *pos = '\v'; break; /* vertical tab */
208 case 'x': /* hex value (1 to 2 digits)(\xNN) */
209 d[2] = '\0'; /* pre-terminate the string */
210
211 /* verify next two characters are hex */
212 d[0] = isxdigit(*(chr+1)) ? *++chr : '\0';
213 if (d[0] != '\0')
214 d[1] = isxdigit(*(chr+1)) ? *++chr : '\0';
215
216 /* convert the characters to decimal */
217 c = (uint8_t)strtoul(d, 0, 16);
218
219 /* assign the converted value */
220 *pos = (c != 0 || d[0] == '0') ? c : *++chr;
221 break;
222 case '0': /* octal value (0 to 3 digits)(\0NNN) */
223 d[3] = '\0'; /* pre-terminate the string */
224
225 /* verify next three characters are octal */
226 d[0] = (isdigit(*(chr+1)) && *(chr+1) < '8') ?
227 *++chr : '\0';
228 if (d[0] != '\0')
229 d[1] = (isdigit(*(chr+1)) && *(chr+1) < '8') ?
230 *++chr : '\0';
231 if (d[1] != '\0')
232 d[2] = (isdigit(*(chr+1)) && *(chr+1) < '8') ?
233 *++chr : '\0';
234
235 /* convert the characters to decimal */
236 c = (uint8_t)strtoul(d, 0, 8);
237
238 /* assign the converted value */
239 *pos = c;
240 break;
241 default: /* single octal (\0..7) or unknown sequence */
242 if (isdigit(*chr) && *chr < '8') {
243 d[0] = *chr;
244 d[1] = '\0';
245 *pos = (uint8_t)strtoul(d, 0, 8);
246 } else
247 *pos = *chr;
248 }
249
250 /* Increment to next offset, possible next escape sequence */
251 pos++;
252 chr++;
253 }
254 }
255
256 /*
257 * Expand only the escaped newlines in a buffer pointed to by `source'. This
258 * function steps through each character, and converts the "\n" sequence into
259 * a literal newline and the "\\n" sequence into "\n".
260 *
261 * You should not pass a string constant or literal to this function or the
262 * program will likely segmentation fault when it tries to modify the data.
263 *
264 * The string length will either shorten or stay the same depending on whether
265 * any escaped newlines were converted but the amount of memory allocated does
266 * not change.
267 */
strexpandnl(char * source)268 void strexpandnl(char *source)
269 {
270 uint8_t backslash = 0;
271 char *cp1;
272 char *cp2;
273
274 /* Replace '\n' with literal in dprompt */
275 cp1 = cp2 = source;
276 while (*cp2 != '\0') {
277 *cp1 = *cp2;
278 if (*cp2 == '\\')
279 backslash++;
280 else if (*cp2 != 'n')
281 backslash = 0;
282 else if (backslash > 0) {
283 *(--cp1) = (backslash & 1) == 1 ? '\n' : 'n';
284 backslash = 0;
285 }
286 cp1++;
287 cp2++;
288 }
289 *cp1 = *cp2;
290 }
291
292 /*
293 * Convert a string to lower case. You should not pass a string constant to
294 * this function. Only pass pointers to allocated memory with null terminated
295 * string data.
296 */
297 void
strtolower(char * source)298 strtolower(char *source)
299 {
300 char *p = source;
301
302 if (source == NULL)
303 return;
304
305 while (*p != '\0') {
306 *p = tolower(*p);
307 p++; /* would have just used `*p++' but gcc 3.x warns */
308 }
309 }
310