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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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/module.h>
26
27#ifndef __HAVE_ARCH_STRNICMP
28/**
29 * strnicmp - Case insensitive, length-limited string comparison
30 * @s1: One string
31 * @s2: The other string
32 * @len: the maximum number of characters to compare
33 */
34int strnicmp(const char *s1, const char *s2, size_t len)
35{
36 /* Yes, Virginia, it had better be unsigned */
37 unsigned char c1, c2;
38
Jesper Juhl850b9242005-10-30 15:02:13 -080039 c1 = c2 = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 if (len) {
41 do {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -080042 c1 = *s1;
43 c2 = *s2;
44 s1++;
45 s2++;
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 if (!c1)
47 break;
48 if (!c2)
49 break;
50 if (c1 == c2)
51 continue;
52 c1 = tolower(c1);
53 c2 = tolower(c2);
54 if (c1 != c2)
55 break;
56 } while (--len);
57 }
58 return (int)c1 - (int)c2;
59}
Linus Torvalds1da177e2005-04-16 15:20:36 -070060EXPORT_SYMBOL(strnicmp);
61#endif
62
63#ifndef __HAVE_ARCH_STRCPY
64/**
65 * strcpy - Copy a %NUL terminated string
66 * @dest: Where to copy the string to
67 * @src: Where to copy the string from
68 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -070069#undef strcpy
Jesper Juhl51a0f0f2005-10-30 15:02:11 -080070char *strcpy(char *dest, const char *src)
Linus Torvalds1da177e2005-04-16 15:20:36 -070071{
72 char *tmp = dest;
73
74 while ((*dest++ = *src++) != '\0')
75 /* nothing */;
76 return tmp;
77}
78EXPORT_SYMBOL(strcpy);
79#endif
80
81#ifndef __HAVE_ARCH_STRNCPY
82/**
83 * strncpy - Copy a length-limited, %NUL-terminated string
84 * @dest: Where to copy the string to
85 * @src: Where to copy the string from
86 * @count: The maximum number of bytes to copy
87 *
88 * The result is not %NUL-terminated if the source exceeds
89 * @count bytes.
walter harms25279522005-05-05 16:16:20 -070090 *
91 * In the case where the length of @src is less than that of
92 * count, the remainder of @dest will be padded with %NUL.
93 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -080095char *strncpy(char *dest, const char *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -070096{
97 char *tmp = dest;
98
99 while (count) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800100 if ((*tmp = *src) != 0)
101 src++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 tmp++;
103 count--;
104 }
105 return dest;
106}
107EXPORT_SYMBOL(strncpy);
108#endif
109
110#ifndef __HAVE_ARCH_STRLCPY
111/**
112 * strlcpy - Copy a %NUL terminated string into a sized buffer
113 * @dest: Where to copy the string to
114 * @src: Where to copy the string from
115 * @size: size of destination buffer
116 *
117 * Compatible with *BSD: the result is always a valid
118 * NUL-terminated string that fits in the buffer (unless,
119 * of course, the buffer size is zero). It does not pad
120 * out the result like strncpy() does.
121 */
122size_t strlcpy(char *dest, const char *src, size_t size)
123{
124 size_t ret = strlen(src);
125
126 if (size) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800127 size_t len = (ret >= size) ? size - 1 : ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 memcpy(dest, src, len);
129 dest[len] = '\0';
130 }
131 return ret;
132}
133EXPORT_SYMBOL(strlcpy);
134#endif
135
136#ifndef __HAVE_ARCH_STRCAT
137/**
138 * strcat - Append one %NUL-terminated string to another
139 * @dest: The string to be appended to
140 * @src: The string to append to it
141 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700142#undef strcat
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800143char *strcat(char *dest, const char *src)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144{
145 char *tmp = dest;
146
147 while (*dest)
148 dest++;
149 while ((*dest++ = *src++) != '\0')
150 ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 return tmp;
152}
153EXPORT_SYMBOL(strcat);
154#endif
155
156#ifndef __HAVE_ARCH_STRNCAT
157/**
158 * strncat - Append a length-limited, %NUL-terminated string to another
159 * @dest: The string to be appended to
160 * @src: The string to append to it
161 * @count: The maximum numbers of bytes to copy
162 *
163 * Note that in contrast to strncpy, strncat ensures the result is
164 * terminated.
165 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800166char *strncat(char *dest, const char *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167{
168 char *tmp = dest;
169
170 if (count) {
171 while (*dest)
172 dest++;
173 while ((*dest++ = *src++) != 0) {
174 if (--count == 0) {
175 *dest = '\0';
176 break;
177 }
178 }
179 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 return tmp;
181}
182EXPORT_SYMBOL(strncat);
183#endif
184
185#ifndef __HAVE_ARCH_STRLCAT
186/**
187 * strlcat - Append a length-limited, %NUL-terminated string to another
188 * @dest: The string to be appended to
189 * @src: The string to append to it
190 * @count: The size of the destination buffer.
191 */
192size_t strlcat(char *dest, const char *src, size_t count)
193{
194 size_t dsize = strlen(dest);
195 size_t len = strlen(src);
196 size_t res = dsize + len;
197
198 /* This would be a bug */
199 BUG_ON(dsize >= count);
200
201 dest += dsize;
202 count -= dsize;
203 if (len >= count)
204 len = count-1;
205 memcpy(dest, src, len);
206 dest[len] = 0;
207 return res;
208}
209EXPORT_SYMBOL(strlcat);
210#endif
211
212#ifndef __HAVE_ARCH_STRCMP
213/**
214 * strcmp - Compare two strings
215 * @cs: One string
216 * @ct: Another string
217 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700218#undef strcmp
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800219int strcmp(const char *cs, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220{
Jesper Juhlcc75fb72005-10-30 15:02:12 -0800221 signed char __res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
223 while (1) {
224 if ((__res = *cs - *ct++) != 0 || !*cs++)
225 break;
226 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 return __res;
228}
229EXPORT_SYMBOL(strcmp);
230#endif
231
232#ifndef __HAVE_ARCH_STRNCMP
233/**
234 * strncmp - Compare two length-limited strings
235 * @cs: One string
236 * @ct: Another string
237 * @count: The maximum number of bytes to compare
238 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800239int strncmp(const char *cs, const char *ct, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240{
Jesper Juhlcc75fb72005-10-30 15:02:12 -0800241 signed char __res = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242
243 while (count) {
244 if ((__res = *cs - *ct++) != 0 || !*cs++)
245 break;
246 count--;
247 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 return __res;
249}
250EXPORT_SYMBOL(strncmp);
251#endif
252
253#ifndef __HAVE_ARCH_STRCHR
254/**
255 * strchr - Find the first occurrence of a character in a string
256 * @s: The string to be searched
257 * @c: The character to search for
258 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800259char *strchr(const char *s, int c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800261 for (; *s != (char)c; ++s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 if (*s == '\0')
263 return NULL;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800264 return (char *)s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265}
266EXPORT_SYMBOL(strchr);
267#endif
268
269#ifndef __HAVE_ARCH_STRRCHR
270/**
271 * strrchr - Find the last occurrence of a character in a string
272 * @s: The string to be searched
273 * @c: The character to search for
274 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800275char *strrchr(const char *s, int c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276{
277 const char *p = s + strlen(s);
278 do {
279 if (*p == (char)c)
280 return (char *)p;
281 } while (--p >= s);
282 return NULL;
283}
284EXPORT_SYMBOL(strrchr);
285#endif
286
287#ifndef __HAVE_ARCH_STRNCHR
288/**
289 * strnchr - Find a character in a length limited string
290 * @s: The string to be searched
291 * @count: The number of characters to be searched
292 * @c: The character to search for
293 */
294char *strnchr(const char *s, size_t count, int c)
295{
296 for (; count-- && *s != '\0'; ++s)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800297 if (*s == (char)c)
298 return (char *)s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 return NULL;
300}
301EXPORT_SYMBOL(strnchr);
302#endif
303
304#ifndef __HAVE_ARCH_STRLEN
305/**
306 * strlen - Find the length of a string
307 * @s: The string to be sized
308 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800309size_t strlen(const char *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310{
311 const char *sc;
312
313 for (sc = s; *sc != '\0'; ++sc)
314 /* nothing */;
315 return sc - s;
316}
317EXPORT_SYMBOL(strlen);
318#endif
319
320#ifndef __HAVE_ARCH_STRNLEN
321/**
322 * strnlen - Find the length of a length-limited string
323 * @s: The string to be sized
324 * @count: The maximum number of bytes to search
325 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800326size_t strnlen(const char *s, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327{
328 const char *sc;
329
330 for (sc = s; count-- && *sc != '\0'; ++sc)
331 /* nothing */;
332 return sc - s;
333}
334EXPORT_SYMBOL(strnlen);
335#endif
336
337#ifndef __HAVE_ARCH_STRSPN
338/**
339 * strspn - Calculate the length of the initial substring of @s which only
340 * contain letters in @accept
341 * @s: The string to be searched
342 * @accept: The string to search for
343 */
344size_t strspn(const char *s, const char *accept)
345{
346 const char *p;
347 const char *a;
348 size_t count = 0;
349
350 for (p = s; *p != '\0'; ++p) {
351 for (a = accept; *a != '\0'; ++a) {
352 if (*p == *a)
353 break;
354 }
355 if (*a == '\0')
356 return count;
357 ++count;
358 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 return count;
360}
361
362EXPORT_SYMBOL(strspn);
363#endif
364
Kyle McMartin8833d322006-04-10 22:53:57 -0700365#ifndef __HAVE_ARCH_STRCSPN
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366/**
367 * strcspn - Calculate the length of the initial substring of @s which does
368 * not contain letters in @reject
369 * @s: The string to be searched
370 * @reject: The string to avoid
371 */
372size_t strcspn(const char *s, const char *reject)
373{
374 const char *p;
375 const char *r;
376 size_t count = 0;
377
378 for (p = s; *p != '\0'; ++p) {
379 for (r = reject; *r != '\0'; ++r) {
380 if (*p == *r)
381 return count;
382 }
383 ++count;
384 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 return count;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800386}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387EXPORT_SYMBOL(strcspn);
Kyle McMartin8833d322006-04-10 22:53:57 -0700388#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389
390#ifndef __HAVE_ARCH_STRPBRK
391/**
392 * strpbrk - Find the first occurrence of a set of characters
393 * @cs: The string to be searched
394 * @ct: The characters to search for
395 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800396char *strpbrk(const char *cs, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800398 const char *sc1, *sc2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800400 for (sc1 = cs; *sc1 != '\0'; ++sc1) {
401 for (sc2 = ct; *sc2 != '\0'; ++sc2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 if (*sc1 == *sc2)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800403 return (char *)sc1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 }
405 }
406 return NULL;
407}
Kyle McMartin894b5772006-04-10 22:53:56 -0700408EXPORT_SYMBOL(strpbrk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409#endif
410
411#ifndef __HAVE_ARCH_STRSEP
412/**
413 * strsep - Split a string into tokens
414 * @s: The string to be searched
415 * @ct: The characters to search for
416 *
417 * strsep() updates @s to point after the token, ready for the next call.
418 *
419 * It returns empty tokens, too, behaving exactly like the libc function
420 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
421 * Same semantics, slimmer shape. ;)
422 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800423char *strsep(char **s, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800425 char *sbegin = *s;
426 char *end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427
428 if (sbegin == NULL)
429 return NULL;
430
431 end = strpbrk(sbegin, ct);
432 if (end)
433 *end++ = '\0';
434 *s = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 return sbegin;
436}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437EXPORT_SYMBOL(strsep);
438#endif
439
440#ifndef __HAVE_ARCH_MEMSET
441/**
442 * memset - Fill a region of memory with the given value
443 * @s: Pointer to the start of the area.
444 * @c: The byte to fill the area with
445 * @count: The size of the area.
446 *
447 * Do not use memset() to access IO space, use memset_io() instead.
448 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800449void *memset(void *s, int c, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450{
Jesper Juhl850b9242005-10-30 15:02:13 -0800451 char *xs = s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452
453 while (count--)
454 *xs++ = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 return s;
456}
457EXPORT_SYMBOL(memset);
458#endif
459
460#ifndef __HAVE_ARCH_MEMCPY
461/**
462 * memcpy - Copy one area of memory to another
463 * @dest: Where to copy to
464 * @src: Where to copy from
465 * @count: The size of the area.
466 *
467 * You should not use this function to access IO space, use memcpy_toio()
468 * or memcpy_fromio() instead.
469 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800470void *memcpy(void *dest, const void *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471{
Jesper Juhl850b9242005-10-30 15:02:13 -0800472 char *tmp = dest;
473 char *s = src;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474
475 while (count--)
476 *tmp++ = *s++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 return dest;
478}
479EXPORT_SYMBOL(memcpy);
480#endif
481
482#ifndef __HAVE_ARCH_MEMMOVE
483/**
484 * memmove - Copy one area of memory to another
485 * @dest: Where to copy to
486 * @src: Where to copy from
487 * @count: The size of the area.
488 *
489 * Unlike memcpy(), memmove() copes with overlapping areas.
490 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800491void *memmove(void *dest, const void *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492{
Paul Jackson82da2c32005-10-30 15:03:19 -0800493 char *tmp;
494 const char *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495
496 if (dest <= src) {
Jesper Juhl850b9242005-10-30 15:02:13 -0800497 tmp = dest;
498 s = src;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 while (count--)
500 *tmp++ = *s++;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800501 } else {
Jesper Juhl850b9242005-10-30 15:02:13 -0800502 tmp = dest;
503 tmp += count;
504 s = src;
505 s += count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 while (count--)
507 *--tmp = *--s;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800508 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 return dest;
510}
511EXPORT_SYMBOL(memmove);
512#endif
513
514#ifndef __HAVE_ARCH_MEMCMP
515/**
516 * memcmp - Compare two areas of memory
517 * @cs: One area of memory
518 * @ct: Another area of memory
519 * @count: The size of the area.
520 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700521#undef memcmp
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800522int memcmp(const void *cs, const void *ct, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523{
524 const unsigned char *su1, *su2;
525 int res = 0;
526
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800527 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 if ((res = *su1 - *su2) != 0)
529 break;
530 return res;
531}
532EXPORT_SYMBOL(memcmp);
533#endif
534
535#ifndef __HAVE_ARCH_MEMSCAN
536/**
537 * memscan - Find a character in an area of memory.
538 * @addr: The memory area
539 * @c: The byte to search for
540 * @size: The size of the area.
541 *
542 * returns the address of the first occurrence of @c, or 1 byte past
543 * the area if @c is not found
544 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800545void *memscan(void *addr, int c, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546{
Jesper Juhl850b9242005-10-30 15:02:13 -0800547 unsigned char *p = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548
549 while (size) {
550 if (*p == c)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800551 return (void *)p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 p++;
553 size--;
554 }
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800555 return (void *)p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556}
557EXPORT_SYMBOL(memscan);
558#endif
559
560#ifndef __HAVE_ARCH_STRSTR
561/**
562 * strstr - Find the first substring in a %NUL terminated string
563 * @s1: The string to be searched
564 * @s2: The string to search for
565 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800566char *strstr(const char *s1, const char *s2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567{
568 int l1, l2;
569
570 l2 = strlen(s2);
571 if (!l2)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800572 return (char *)s1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 l1 = strlen(s1);
574 while (l1 >= l2) {
575 l1--;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800576 if (!memcmp(s1, s2, l2))
577 return (char *)s1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 s1++;
579 }
580 return NULL;
581}
582EXPORT_SYMBOL(strstr);
583#endif
584
585#ifndef __HAVE_ARCH_MEMCHR
586/**
587 * memchr - Find a character in an area of memory.
588 * @s: The memory area
589 * @c: The byte to search for
590 * @n: The size of the area.
591 *
592 * returns the address of the first occurrence of @c, or %NULL
593 * if @c is not found
594 */
595void *memchr(const void *s, int c, size_t n)
596{
597 const unsigned char *p = s;
598 while (n-- != 0) {
599 if ((unsigned char)c == *p++) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800600 return (void *)(p - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 }
602 }
603 return NULL;
604}
605EXPORT_SYMBOL(memchr);
606#endif