blob: 1cd9757291b1f94907575be1526fe09e927aa68f
1 | /* |
2 | * linux/lib/string.c |
3 | * |
4 | * Copyright (C) 1991, 1992 Linus Torvalds |
5 | */ |
6 | |
7 | /* |
8 | * stupid library routines.. The optimized versions should generally be found |
9 | * as inline code in <asm-xx/string.h> |
10 | * |
11 | * These are buggy as well.. |
12 | * |
13 | * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de> |
14 | * - Added strsep() which will replace strtok() soon (because strsep() is |
15 | * reentrant and should be faster). Use only strsep() in new code, please. |
16 | * |
17 | * * Sat Feb 09 2002, Jason Thomas <jason@topic.com.au>, |
18 | * Matthew Hawkins <matt@mh.dropbear.id.au> |
19 | * - Kissed strtok() goodbye |
20 | */ |
21 | |
22 | #include <linux/types.h> |
23 | #include <linux/string.h> |
24 | #include <linux/ctype.h> |
25 | #include <linux/kernel.h> |
26 | #include <linux/export.h> |
27 | #include <linux/bug.h> |
28 | #include <linux/errno.h> |
29 | |
30 | #include <asm/byteorder.h> |
31 | #include <asm/word-at-a-time.h> |
32 | #include <asm/page.h> |
33 | |
34 | #ifndef __HAVE_ARCH_STRNCASECMP |
35 | /** |
36 | * strncasecmp - Case insensitive, length-limited string comparison |
37 | * @s1: One string |
38 | * @s2: The other string |
39 | * @len: the maximum number of characters to compare |
40 | */ |
41 | int strncasecmp(const char *s1, const char *s2, size_t len) |
42 | { |
43 | /* Yes, Virginia, it had better be unsigned */ |
44 | unsigned char c1, c2; |
45 | |
46 | if (!len) |
47 | return 0; |
48 | |
49 | do { |
50 | c1 = *s1++; |
51 | c2 = *s2++; |
52 | if (!c1 || !c2) |
53 | break; |
54 | if (c1 == c2) |
55 | continue; |
56 | c1 = tolower(c1); |
57 | c2 = tolower(c2); |
58 | if (c1 != c2) |
59 | break; |
60 | } while (--len); |
61 | return (int)c1 - (int)c2; |
62 | } |
63 | EXPORT_SYMBOL(strncasecmp); |
64 | #endif |
65 | |
66 | #ifndef __HAVE_ARCH_STRCASECMP |
67 | int strcasecmp(const char *s1, const char *s2) |
68 | { |
69 | int c1, c2; |
70 | |
71 | do { |
72 | c1 = tolower(*s1++); |
73 | c2 = tolower(*s2++); |
74 | } while (c1 == c2 && c1 != 0); |
75 | return c1 - c2; |
76 | } |
77 | EXPORT_SYMBOL(strcasecmp); |
78 | #endif |
79 | |
80 | #ifndef __HAVE_ARCH_STRCPY |
81 | /** |
82 | * strcpy - Copy a %NUL terminated string |
83 | * @dest: Where to copy the string to |
84 | * @src: Where to copy the string from |
85 | */ |
86 | #undef strcpy |
87 | char *strcpy(char *dest, const char *src) |
88 | { |
89 | char *tmp = dest; |
90 | |
91 | while ((*dest++ = *src++) != '\0') |
92 | /* nothing */; |
93 | return tmp; |
94 | } |
95 | EXPORT_SYMBOL(strcpy); |
96 | #endif |
97 | |
98 | #ifndef __HAVE_ARCH_STRNCPY |
99 | /** |
100 | * strncpy - Copy a length-limited, C-string |
101 | * @dest: Where to copy the string to |
102 | * @src: Where to copy the string from |
103 | * @count: The maximum number of bytes to copy |
104 | * |
105 | * The result is not %NUL-terminated if the source exceeds |
106 | * @count bytes. |
107 | * |
108 | * In the case where the length of @src is less than that of |
109 | * count, the remainder of @dest will be padded with %NUL. |
110 | * |
111 | */ |
112 | char *strncpy(char *dest, const char *src, size_t count) |
113 | { |
114 | char *tmp = dest; |
115 | |
116 | while (count) { |
117 | if ((*tmp = *src) != 0) |
118 | src++; |
119 | tmp++; |
120 | count--; |
121 | } |
122 | return dest; |
123 | } |
124 | EXPORT_SYMBOL(strncpy); |
125 | #endif |
126 | |
127 | #ifndef __HAVE_ARCH_STRLCPY |
128 | /** |
129 | * strlcpy - Copy a C-string into a sized buffer |
130 | * @dest: Where to copy the string to |
131 | * @src: Where to copy the string from |
132 | * @size: size of destination buffer |
133 | * |
134 | * Compatible with *BSD: the result is always a valid |
135 | * NUL-terminated string that fits in the buffer (unless, |
136 | * of course, the buffer size is zero). It does not pad |
137 | * out the result like strncpy() does. |
138 | */ |
139 | size_t strlcpy(char *dest, const char *src, size_t size) |
140 | { |
141 | size_t ret = strlen(src); |
142 | |
143 | if (size) { |
144 | size_t len = (ret >= size) ? size - 1 : ret; |
145 | memcpy(dest, src, len); |
146 | dest[len] = '\0'; |
147 | } |
148 | return ret; |
149 | } |
150 | EXPORT_SYMBOL(strlcpy); |
151 | #endif |
152 | |
153 | #ifndef __HAVE_ARCH_STRSCPY |
154 | /** |
155 | * strscpy - Copy a C-string into a sized buffer |
156 | * @dest: Where to copy the string to |
157 | * @src: Where to copy the string from |
158 | * @count: Size of destination buffer |
159 | * |
160 | * Copy the string, or as much of it as fits, into the dest buffer. |
161 | * The routine returns the number of characters copied (not including |
162 | * the trailing NUL) or -E2BIG if the destination buffer wasn't big enough. |
163 | * The behavior is undefined if the string buffers overlap. |
164 | * The destination buffer is always NUL terminated, unless it's zero-sized. |
165 | * |
166 | * Preferred to strlcpy() since the API doesn't require reading memory |
167 | * from the src string beyond the specified "count" bytes, and since |
168 | * the return value is easier to error-check than strlcpy()'s. |
169 | * In addition, the implementation is robust to the string changing out |
170 | * from underneath it, unlike the current strlcpy() implementation. |
171 | * |
172 | * Preferred to strncpy() since it always returns a valid string, and |
173 | * doesn't unnecessarily force the tail of the destination buffer to be |
174 | * zeroed. If the zeroing is desired, it's likely cleaner to use strscpy() |
175 | * with an overflow test, then just memset() the tail of the dest buffer. |
176 | */ |
177 | ssize_t strscpy(char *dest, const char *src, size_t count) |
178 | { |
179 | const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; |
180 | size_t max = count; |
181 | long res = 0; |
182 | |
183 | if (count == 0) |
184 | return -E2BIG; |
185 | |
186 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS |
187 | /* |
188 | * If src is unaligned, don't cross a page boundary, |
189 | * since we don't know if the next page is mapped. |
190 | */ |
191 | if ((long)src & (sizeof(long) - 1)) { |
192 | size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1)); |
193 | if (limit < max) |
194 | max = limit; |
195 | } |
196 | #else |
197 | /* If src or dest is unaligned, don't do word-at-a-time. */ |
198 | if (((long) dest | (long) src) & (sizeof(long) - 1)) |
199 | max = 0; |
200 | #endif |
201 | |
202 | while (max >= sizeof(unsigned long)) { |
203 | unsigned long c, data; |
204 | |
205 | c = *(unsigned long *)(src+res); |
206 | if (has_zero(c, &data, &constants)) { |
207 | data = prep_zero_mask(c, data, &constants); |
208 | data = create_zero_mask(data); |
209 | *(unsigned long *)(dest+res) = c & zero_bytemask(data); |
210 | return res + find_zero(data); |
211 | } |
212 | *(unsigned long *)(dest+res) = c; |
213 | res += sizeof(unsigned long); |
214 | count -= sizeof(unsigned long); |
215 | max -= sizeof(unsigned long); |
216 | } |
217 | |
218 | while (count) { |
219 | char c; |
220 | |
221 | c = src[res]; |
222 | dest[res] = c; |
223 | if (!c) |
224 | return res; |
225 | res++; |
226 | count--; |
227 | } |
228 | |
229 | /* Hit buffer length without finding a NUL; force NUL-termination. */ |
230 | if (res) |
231 | dest[res-1] = '\0'; |
232 | |
233 | return -E2BIG; |
234 | } |
235 | EXPORT_SYMBOL(strscpy); |
236 | #endif |
237 | |
238 | #ifndef __HAVE_ARCH_STRCAT |
239 | /** |
240 | * strcat - Append one %NUL-terminated string to another |
241 | * @dest: The string to be appended to |
242 | * @src: The string to append to it |
243 | */ |
244 | #undef strcat |
245 | char *strcat(char *dest, const char *src) |
246 | { |
247 | char *tmp = dest; |
248 | |
249 | while (*dest) |
250 | dest++; |
251 | while ((*dest++ = *src++) != '\0') |
252 | ; |
253 | return tmp; |
254 | } |
255 | EXPORT_SYMBOL(strcat); |
256 | #endif |
257 | |
258 | #ifndef __HAVE_ARCH_STRNCAT |
259 | /** |
260 | * strncat - Append a length-limited, C-string to another |
261 | * @dest: The string to be appended to |
262 | * @src: The string to append to it |
263 | * @count: The maximum numbers of bytes to copy |
264 | * |
265 | * Note that in contrast to strncpy(), strncat() ensures the result is |
266 | * terminated. |
267 | */ |
268 | char *strncat(char *dest, const char *src, size_t count) |
269 | { |
270 | char *tmp = dest; |
271 | |
272 | if (count) { |
273 | while (*dest) |
274 | dest++; |
275 | while ((*dest++ = *src++) != 0) { |
276 | if (--count == 0) { |
277 | *dest = '\0'; |
278 | break; |
279 | } |
280 | } |
281 | } |
282 | return tmp; |
283 | } |
284 | EXPORT_SYMBOL(strncat); |
285 | #endif |
286 | |
287 | #ifndef __HAVE_ARCH_STRLCAT |
288 | /** |
289 | * strlcat - Append a length-limited, C-string to another |
290 | * @dest: The string to be appended to |
291 | * @src: The string to append to it |
292 | * @count: The size of the destination buffer. |
293 | */ |
294 | size_t strlcat(char *dest, const char *src, size_t count) |
295 | { |
296 | size_t dsize = strlen(dest); |
297 | size_t len = strlen(src); |
298 | size_t res = dsize + len; |
299 | |
300 | /* This would be a bug */ |
301 | BUG_ON(dsize >= count); |
302 | |
303 | dest += dsize; |
304 | count -= dsize; |
305 | if (len >= count) |
306 | len = count-1; |
307 | memcpy(dest, src, len); |
308 | dest[len] = 0; |
309 | return res; |
310 | } |
311 | EXPORT_SYMBOL(strlcat); |
312 | #endif |
313 | |
314 | #ifndef __HAVE_ARCH_STRCMP |
315 | /** |
316 | * strcmp - Compare two strings |
317 | * @cs: One string |
318 | * @ct: Another string |
319 | */ |
320 | #undef strcmp |
321 | int strcmp(const char *cs, const char *ct) |
322 | { |
323 | unsigned char c1, c2; |
324 | |
325 | while (1) { |
326 | c1 = *cs++; |
327 | c2 = *ct++; |
328 | if (c1 != c2) |
329 | return c1 < c2 ? -1 : 1; |
330 | if (!c1) |
331 | break; |
332 | } |
333 | return 0; |
334 | } |
335 | EXPORT_SYMBOL(strcmp); |
336 | #endif |
337 | |
338 | #ifndef __HAVE_ARCH_STRNCMP |
339 | /** |
340 | * strncmp - Compare two length-limited strings |
341 | * @cs: One string |
342 | * @ct: Another string |
343 | * @count: The maximum number of bytes to compare |
344 | */ |
345 | int strncmp(const char *cs, const char *ct, size_t count) |
346 | { |
347 | unsigned char c1, c2; |
348 | |
349 | while (count) { |
350 | c1 = *cs++; |
351 | c2 = *ct++; |
352 | if (c1 != c2) |
353 | return c1 < c2 ? -1 : 1; |
354 | if (!c1) |
355 | break; |
356 | count--; |
357 | } |
358 | return 0; |
359 | } |
360 | EXPORT_SYMBOL(strncmp); |
361 | #endif |
362 | |
363 | #ifndef __HAVE_ARCH_STRCHR |
364 | /** |
365 | * strchr - Find the first occurrence of a character in a string |
366 | * @s: The string to be searched |
367 | * @c: The character to search for |
368 | */ |
369 | char *strchr(const char *s, int c) |
370 | { |
371 | for (; *s != (char)c; ++s) |
372 | if (*s == '\0') |
373 | return NULL; |
374 | return (char *)s; |
375 | } |
376 | EXPORT_SYMBOL(strchr); |
377 | #endif |
378 | |
379 | #ifndef __HAVE_ARCH_STRCHRNUL |
380 | /** |
381 | * strchrnul - Find and return a character in a string, or end of string |
382 | * @s: The string to be searched |
383 | * @c: The character to search for |
384 | * |
385 | * Returns pointer to first occurrence of 'c' in s. If c is not found, then |
386 | * return a pointer to the null byte at the end of s. |
387 | */ |
388 | char *strchrnul(const char *s, int c) |
389 | { |
390 | while (*s && *s != (char)c) |
391 | s++; |
392 | return (char *)s; |
393 | } |
394 | EXPORT_SYMBOL(strchrnul); |
395 | #endif |
396 | |
397 | #ifndef __HAVE_ARCH_STRRCHR |
398 | /** |
399 | * strrchr - Find the last occurrence of a character in a string |
400 | * @s: The string to be searched |
401 | * @c: The character to search for |
402 | */ |
403 | char *strrchr(const char *s, int c) |
404 | { |
405 | const char *last = NULL; |
406 | do { |
407 | if (*s == (char)c) |
408 | last = s; |
409 | } while (*s++); |
410 | return (char *)last; |
411 | } |
412 | EXPORT_SYMBOL(strrchr); |
413 | #endif |
414 | |
415 | #ifndef __HAVE_ARCH_STRNCHR |
416 | /** |
417 | * strnchr - Find a character in a length limited string |
418 | * @s: The string to be searched |
419 | * @count: The number of characters to be searched |
420 | * @c: The character to search for |
421 | */ |
422 | char *strnchr(const char *s, size_t count, int c) |
423 | { |
424 | for (; count-- && *s != '\0'; ++s) |
425 | if (*s == (char)c) |
426 | return (char *)s; |
427 | return NULL; |
428 | } |
429 | EXPORT_SYMBOL(strnchr); |
430 | #endif |
431 | |
432 | /** |
433 | * skip_spaces - Removes leading whitespace from @str. |
434 | * @str: The string to be stripped. |
435 | * |
436 | * Returns a pointer to the first non-whitespace character in @str. |
437 | */ |
438 | char *skip_spaces(const char *str) |
439 | { |
440 | while (isspace(*str)) |
441 | ++str; |
442 | return (char *)str; |
443 | } |
444 | EXPORT_SYMBOL(skip_spaces); |
445 | |
446 | /** |
447 | * strim - Removes leading and trailing whitespace from @s. |
448 | * @s: The string to be stripped. |
449 | * |
450 | * Note that the first trailing whitespace is replaced with a %NUL-terminator |
451 | * in the given string @s. Returns a pointer to the first non-whitespace |
452 | * character in @s. |
453 | */ |
454 | char *strim(char *s) |
455 | { |
456 | size_t size; |
457 | char *end; |
458 | |
459 | size = strlen(s); |
460 | if (!size) |
461 | return s; |
462 | |
463 | end = s + size - 1; |
464 | while (end >= s && isspace(*end)) |
465 | end--; |
466 | *(end + 1) = '\0'; |
467 | |
468 | return skip_spaces(s); |
469 | } |
470 | EXPORT_SYMBOL(strim); |
471 | |
472 | #ifndef __HAVE_ARCH_STRLEN |
473 | /** |
474 | * strlen - Find the length of a string |
475 | * @s: The string to be sized |
476 | */ |
477 | size_t strlen(const char *s) |
478 | { |
479 | const char *sc; |
480 | |
481 | for (sc = s; *sc != '\0'; ++sc) |
482 | /* nothing */; |
483 | return sc - s; |
484 | } |
485 | EXPORT_SYMBOL(strlen); |
486 | #endif |
487 | |
488 | #ifndef __HAVE_ARCH_STRNLEN |
489 | /** |
490 | * strnlen - Find the length of a length-limited string |
491 | * @s: The string to be sized |
492 | * @count: The maximum number of bytes to search |
493 | */ |
494 | size_t strnlen(const char *s, size_t count) |
495 | { |
496 | const char *sc; |
497 | |
498 | for (sc = s; count-- && *sc != '\0'; ++sc) |
499 | /* nothing */; |
500 | return sc - s; |
501 | } |
502 | EXPORT_SYMBOL(strnlen); |
503 | #endif |
504 | |
505 | #ifndef __HAVE_ARCH_STRSPN |
506 | /** |
507 | * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept |
508 | * @s: The string to be searched |
509 | * @accept: The string to search for |
510 | */ |
511 | size_t strspn(const char *s, const char *accept) |
512 | { |
513 | const char *p; |
514 | const char *a; |
515 | size_t count = 0; |
516 | |
517 | for (p = s; *p != '\0'; ++p) { |
518 | for (a = accept; *a != '\0'; ++a) { |
519 | if (*p == *a) |
520 | break; |
521 | } |
522 | if (*a == '\0') |
523 | return count; |
524 | ++count; |
525 | } |
526 | return count; |
527 | } |
528 | |
529 | EXPORT_SYMBOL(strspn); |
530 | #endif |
531 | |
532 | #ifndef __HAVE_ARCH_STRCSPN |
533 | /** |
534 | * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject |
535 | * @s: The string to be searched |
536 | * @reject: The string to avoid |
537 | */ |
538 | size_t strcspn(const char *s, const char *reject) |
539 | { |
540 | const char *p; |
541 | const char *r; |
542 | size_t count = 0; |
543 | |
544 | for (p = s; *p != '\0'; ++p) { |
545 | for (r = reject; *r != '\0'; ++r) { |
546 | if (*p == *r) |
547 | return count; |
548 | } |
549 | ++count; |
550 | } |
551 | return count; |
552 | } |
553 | EXPORT_SYMBOL(strcspn); |
554 | #endif |
555 | |
556 | #ifndef __HAVE_ARCH_STRPBRK |
557 | /** |
558 | * strpbrk - Find the first occurrence of a set of characters |
559 | * @cs: The string to be searched |
560 | * @ct: The characters to search for |
561 | */ |
562 | char *strpbrk(const char *cs, const char *ct) |
563 | { |
564 | const char *sc1, *sc2; |
565 | |
566 | for (sc1 = cs; *sc1 != '\0'; ++sc1) { |
567 | for (sc2 = ct; *sc2 != '\0'; ++sc2) { |
568 | if (*sc1 == *sc2) |
569 | return (char *)sc1; |
570 | } |
571 | } |
572 | return NULL; |
573 | } |
574 | EXPORT_SYMBOL(strpbrk); |
575 | #endif |
576 | |
577 | #ifndef __HAVE_ARCH_STRSEP |
578 | /** |
579 | * strsep - Split a string into tokens |
580 | * @s: The string to be searched |
581 | * @ct: The characters to search for |
582 | * |
583 | * strsep() updates @s to point after the token, ready for the next call. |
584 | * |
585 | * It returns empty tokens, too, behaving exactly like the libc function |
586 | * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. |
587 | * Same semantics, slimmer shape. ;) |
588 | */ |
589 | char *strsep(char **s, const char *ct) |
590 | { |
591 | char *sbegin = *s; |
592 | char *end; |
593 | |
594 | if (sbegin == NULL) |
595 | return NULL; |
596 | |
597 | end = strpbrk(sbegin, ct); |
598 | if (end) |
599 | *end++ = '\0'; |
600 | *s = end; |
601 | return sbegin; |
602 | } |
603 | EXPORT_SYMBOL(strsep); |
604 | #endif |
605 | |
606 | /** |
607 | * sysfs_streq - return true if strings are equal, modulo trailing newline |
608 | * @s1: one string |
609 | * @s2: another string |
610 | * |
611 | * This routine returns true iff two strings are equal, treating both |
612 | * NUL and newline-then-NUL as equivalent string terminations. It's |
613 | * geared for use with sysfs input strings, which generally terminate |
614 | * with newlines but are compared against values without newlines. |
615 | */ |
616 | bool sysfs_streq(const char *s1, const char *s2) |
617 | { |
618 | while (*s1 && *s1 == *s2) { |
619 | s1++; |
620 | s2++; |
621 | } |
622 | |
623 | if (*s1 == *s2) |
624 | return true; |
625 | if (!*s1 && *s2 == '\n' && !s2[1]) |
626 | return true; |
627 | if (*s1 == '\n' && !s1[1] && !*s2) |
628 | return true; |
629 | return false; |
630 | } |
631 | EXPORT_SYMBOL(sysfs_streq); |
632 | |
633 | /** |
634 | * match_string - matches given string in an array |
635 | * @array: array of strings |
636 | * @n: number of strings in the array or -1 for NULL terminated arrays |
637 | * @string: string to match with |
638 | * |
639 | * Return: |
640 | * index of a @string in the @array if matches, or %-EINVAL otherwise. |
641 | */ |
642 | int match_string(const char * const *array, size_t n, const char *string) |
643 | { |
644 | int index; |
645 | const char *item; |
646 | |
647 | for (index = 0; index < n; index++) { |
648 | item = array[index]; |
649 | if (!item) |
650 | break; |
651 | if (!strcmp(item, string)) |
652 | return index; |
653 | } |
654 | |
655 | return -EINVAL; |
656 | } |
657 | EXPORT_SYMBOL(match_string); |
658 | |
659 | #ifndef __HAVE_ARCH_MEMSET |
660 | /** |
661 | * memset - Fill a region of memory with the given value |
662 | * @s: Pointer to the start of the area. |
663 | * @c: The byte to fill the area with |
664 | * @count: The size of the area. |
665 | * |
666 | * Do not use memset() to access IO space, use memset_io() instead. |
667 | */ |
668 | void *memset(void *s, int c, size_t count) |
669 | { |
670 | char *xs = s; |
671 | |
672 | while (count--) |
673 | *xs++ = c; |
674 | return s; |
675 | } |
676 | EXPORT_SYMBOL(memset); |
677 | #endif |
678 | |
679 | /** |
680 | * memzero_explicit - Fill a region of memory (e.g. sensitive |
681 | * keying data) with 0s. |
682 | * @s: Pointer to the start of the area. |
683 | * @count: The size of the area. |
684 | * |
685 | * Note: usually using memset() is just fine (!), but in cases |
686 | * where clearing out _local_ data at the end of a scope is |
687 | * necessary, memzero_explicit() should be used instead in |
688 | * order to prevent the compiler from optimising away zeroing. |
689 | * |
690 | * memzero_explicit() doesn't need an arch-specific version as |
691 | * it just invokes the one of memset() implicitly. |
692 | */ |
693 | void memzero_explicit(void *s, size_t count) |
694 | { |
695 | memset(s, 0, count); |
696 | barrier_data(s); |
697 | } |
698 | EXPORT_SYMBOL(memzero_explicit); |
699 | |
700 | #ifndef __HAVE_ARCH_MEMCPY |
701 | /** |
702 | * memcpy - Copy one area of memory to another |
703 | * @dest: Where to copy to |
704 | * @src: Where to copy from |
705 | * @count: The size of the area. |
706 | * |
707 | * You should not use this function to access IO space, use memcpy_toio() |
708 | * or memcpy_fromio() instead. |
709 | */ |
710 | void *memcpy(void *dest, const void *src, size_t count) |
711 | { |
712 | char *tmp = dest; |
713 | const char *s = src; |
714 | |
715 | while (count--) |
716 | *tmp++ = *s++; |
717 | return dest; |
718 | } |
719 | EXPORT_SYMBOL(memcpy); |
720 | #endif |
721 | |
722 | #ifndef __HAVE_ARCH_MEMMOVE |
723 | /** |
724 | * memmove - Copy one area of memory to another |
725 | * @dest: Where to copy to |
726 | * @src: Where to copy from |
727 | * @count: The size of the area. |
728 | * |
729 | * Unlike memcpy(), memmove() copes with overlapping areas. |
730 | */ |
731 | void *memmove(void *dest, const void *src, size_t count) |
732 | { |
733 | char *tmp; |
734 | const char *s; |
735 | |
736 | if (dest <= src) { |
737 | tmp = dest; |
738 | s = src; |
739 | while (count--) |
740 | *tmp++ = *s++; |
741 | } else { |
742 | tmp = dest; |
743 | tmp += count; |
744 | s = src; |
745 | s += count; |
746 | while (count--) |
747 | *--tmp = *--s; |
748 | } |
749 | return dest; |
750 | } |
751 | EXPORT_SYMBOL(memmove); |
752 | #endif |
753 | |
754 | #ifndef __HAVE_ARCH_MEMCMP |
755 | /** |
756 | * memcmp - Compare two areas of memory |
757 | * @cs: One area of memory |
758 | * @ct: Another area of memory |
759 | * @count: The size of the area. |
760 | */ |
761 | #undef memcmp |
762 | __visible int memcmp(const void *cs, const void *ct, size_t count) |
763 | { |
764 | const unsigned char *su1, *su2; |
765 | int res = 0; |
766 | |
767 | for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) |
768 | if ((res = *su1 - *su2) != 0) |
769 | break; |
770 | return res; |
771 | } |
772 | EXPORT_SYMBOL(memcmp); |
773 | #endif |
774 | |
775 | #ifndef __HAVE_ARCH_BCMP |
776 | /** |
777 | * bcmp - returns 0 if and only if the buffers have identical contents. |
778 | * @a: pointer to first buffer. |
779 | * @b: pointer to second buffer. |
780 | * @len: size of buffers. |
781 | * |
782 | * The sign or magnitude of a non-zero return value has no particular |
783 | * meaning, and architectures may implement their own more efficient bcmp(). So |
784 | * while this particular implementation is a simple (tail) call to memcmp, do |
785 | * not rely on anything but whether the return value is zero or non-zero. |
786 | */ |
787 | #undef bcmp |
788 | int bcmp(const void *a, const void *b, size_t len) |
789 | { |
790 | return memcmp(a, b, len); |
791 | } |
792 | EXPORT_SYMBOL(bcmp); |
793 | #endif |
794 | |
795 | #ifndef __HAVE_ARCH_MEMSCAN |
796 | /** |
797 | * memscan - Find a character in an area of memory. |
798 | * @addr: The memory area |
799 | * @c: The byte to search for |
800 | * @size: The size of the area. |
801 | * |
802 | * returns the address of the first occurrence of @c, or 1 byte past |
803 | * the area if @c is not found |
804 | */ |
805 | void *memscan(void *addr, int c, size_t size) |
806 | { |
807 | unsigned char *p = addr; |
808 | |
809 | while (size) { |
810 | if (*p == c) |
811 | return (void *)p; |
812 | p++; |
813 | size--; |
814 | } |
815 | return (void *)p; |
816 | } |
817 | EXPORT_SYMBOL(memscan); |
818 | #endif |
819 | |
820 | #ifndef __HAVE_ARCH_STRSTR |
821 | /** |
822 | * strstr - Find the first substring in a %NUL terminated string |
823 | * @s1: The string to be searched |
824 | * @s2: The string to search for |
825 | */ |
826 | char *strstr(const char *s1, const char *s2) |
827 | { |
828 | size_t l1, l2; |
829 | |
830 | l2 = strlen(s2); |
831 | if (!l2) |
832 | return (char *)s1; |
833 | l1 = strlen(s1); |
834 | while (l1 >= l2) { |
835 | l1--; |
836 | if (!memcmp(s1, s2, l2)) |
837 | return (char *)s1; |
838 | s1++; |
839 | } |
840 | return NULL; |
841 | } |
842 | EXPORT_SYMBOL(strstr); |
843 | #endif |
844 | |
845 | #ifndef __HAVE_ARCH_STRNSTR |
846 | /** |
847 | * strnstr - Find the first substring in a length-limited string |
848 | * @s1: The string to be searched |
849 | * @s2: The string to search for |
850 | * @len: the maximum number of characters to search |
851 | */ |
852 | char *strnstr(const char *s1, const char *s2, size_t len) |
853 | { |
854 | size_t l2; |
855 | |
856 | l2 = strlen(s2); |
857 | if (!l2) |
858 | return (char *)s1; |
859 | while (len >= l2) { |
860 | len--; |
861 | if (!memcmp(s1, s2, l2)) |
862 | return (char *)s1; |
863 | s1++; |
864 | } |
865 | return NULL; |
866 | } |
867 | EXPORT_SYMBOL(strnstr); |
868 | #endif |
869 | |
870 | #ifndef __HAVE_ARCH_MEMCHR |
871 | /** |
872 | * memchr - Find a character in an area of memory. |
873 | * @s: The memory area |
874 | * @c: The byte to search for |
875 | * @n: The size of the area. |
876 | * |
877 | * returns the address of the first occurrence of @c, or %NULL |
878 | * if @c is not found |
879 | */ |
880 | void *memchr(const void *s, int c, size_t n) |
881 | { |
882 | const unsigned char *p = s; |
883 | while (n-- != 0) { |
884 | if ((unsigned char)c == *p++) { |
885 | return (void *)(p - 1); |
886 | } |
887 | } |
888 | return NULL; |
889 | } |
890 | EXPORT_SYMBOL(memchr); |
891 | #endif |
892 | |
893 | static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) |
894 | { |
895 | while (bytes) { |
896 | if (*start != value) |
897 | return (void *)start; |
898 | start++; |
899 | bytes--; |
900 | } |
901 | return NULL; |
902 | } |
903 | |
904 | /** |
905 | * memchr_inv - Find an unmatching character in an area of memory. |
906 | * @start: The memory area |
907 | * @c: Find a character other than c |
908 | * @bytes: The size of the area. |
909 | * |
910 | * returns the address of the first character other than @c, or %NULL |
911 | * if the whole buffer contains just @c. |
912 | */ |
913 | void *memchr_inv(const void *start, int c, size_t bytes) |
914 | { |
915 | u8 value = c; |
916 | u64 value64; |
917 | unsigned int words, prefix; |
918 | |
919 | if (bytes <= 16) |
920 | return check_bytes8(start, value, bytes); |
921 | |
922 | value64 = value; |
923 | #if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 |
924 | value64 *= 0x0101010101010101ULL; |
925 | #elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) |
926 | value64 *= 0x01010101; |
927 | value64 |= value64 << 32; |
928 | #else |
929 | value64 |= value64 << 8; |
930 | value64 |= value64 << 16; |
931 | value64 |= value64 << 32; |
932 | #endif |
933 | |
934 | prefix = (unsigned long)start % 8; |
935 | if (prefix) { |
936 | u8 *r; |
937 | |
938 | prefix = 8 - prefix; |
939 | r = check_bytes8(start, value, prefix); |
940 | if (r) |
941 | return r; |
942 | start += prefix; |
943 | bytes -= prefix; |
944 | } |
945 | |
946 | words = bytes / 8; |
947 | |
948 | while (words) { |
949 | if (*(u64 *)start != value64) |
950 | return check_bytes8(start, value, 8); |
951 | start += 8; |
952 | words--; |
953 | } |
954 | |
955 | return check_bytes8(start, value, bytes % 8); |
956 | } |
957 | EXPORT_SYMBOL(memchr_inv); |
958 | |
959 | /** |
960 | * strreplace - Replace all occurrences of character in string. |
961 | * @s: The string to operate on. |
962 | * @old: The character being replaced. |
963 | * @new: The character @old is replaced with. |
964 | * |
965 | * Returns pointer to the nul byte at the end of @s. |
966 | */ |
967 | char *strreplace(char *s, char old, char new) |
968 | { |
969 | for (; *s; ++s) |
970 | if (*s == old) |
971 | *s = new; |
972 | return s; |
973 | } |
974 | EXPORT_SYMBOL(strreplace); |
975 |