blob: 67d5f6a4213a4c9e3dcdfe067724e4a7885baad6 [file] [log] [blame]
wdenkc6097192002-11-03 00:24:07 +00001/*
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
18#include <linux/types.h>
19#include <linux/string.h>
20#include <linux/ctype.h>
21#include <malloc.h>
22
wdenkc6097192002-11-03 00:24:07 +000023
wdenkc6097192002-11-03 00:24:07 +000024/**
Simon Glassb1f17bf2012-12-05 14:46:35 +000025 * strncasecmp - Case insensitive, length-limited string comparison
wdenkc6097192002-11-03 00:24:07 +000026 * @s1: One string
27 * @s2: The other string
28 * @len: the maximum number of characters to compare
29 */
Simon Glassb1f17bf2012-12-05 14:46:35 +000030int strncasecmp(const char *s1, const char *s2, size_t len)
wdenkc6097192002-11-03 00:24:07 +000031{
32 /* Yes, Virginia, it had better be unsigned */
33 unsigned char c1, c2;
34
35 c1 = 0; c2 = 0;
36 if (len) {
37 do {
38 c1 = *s1; c2 = *s2;
39 s1++; s2++;
40 if (!c1)
41 break;
42 if (!c2)
43 break;
44 if (c1 == c2)
45 continue;
46 c1 = tolower(c1);
47 c2 = tolower(c2);
48 if (c1 != c2)
49 break;
50 } while (--len);
51 }
52 return (int)c1 - (int)c2;
53}
Simon Glassb1f17bf2012-12-05 14:46:35 +000054
55/**
56 * strcasecmp - Case insensitive string comparison
57 * @s1: One string
58 * @s2: The other string
59 */
60int strcasecmp(const char *s1, const char *s2)
61{
62 return strncasecmp(s1, s2, -1U);
63}
wdenkc6097192002-11-03 00:24:07 +000064
65char * ___strtok;
66
67#ifndef __HAVE_ARCH_STRCPY
68/**
69 * strcpy - Copy a %NUL terminated string
70 * @dest: Where to copy the string to
71 * @src: Where to copy the string from
72 */
73char * strcpy(char * dest,const char *src)
74{
75 char *tmp = dest;
76
77 while ((*dest++ = *src++) != '\0')
78 /* nothing */;
79 return tmp;
80}
81#endif
82
83#ifndef __HAVE_ARCH_STRNCPY
84/**
85 * strncpy - Copy a length-limited, %NUL-terminated string
86 * @dest: Where to copy the string to
87 * @src: Where to copy the string from
88 * @count: The maximum number of bytes to copy
89 *
90 * Note that unlike userspace strncpy, this does not %NUL-pad the buffer.
91 * However, the result is not %NUL-terminated if the source exceeds
92 * @count bytes.
93 */
94char * strncpy(char * dest,const char *src,size_t count)
95{
96 char *tmp = dest;
97
98 while (count-- && (*dest++ = *src++) != '\0')
99 /* nothing */;
100
101 return tmp;
102}
103#endif
104
Masahiro Yamada80d9ef82014-11-20 21:20:32 +0900105#ifndef __HAVE_ARCH_STRLCPY
106/**
107 * strlcpy - Copy a C-string into a sized buffer
108 * @dest: Where to copy the string to
109 * @src: Where to copy the string from
110 * @size: size of destination buffer
111 *
112 * Compatible with *BSD: the result is always a valid
113 * NUL-terminated string that fits in the buffer (unless,
114 * of course, the buffer size is zero). It does not pad
115 * out the result like strncpy() does.
116 */
117size_t strlcpy(char *dest, const char *src, size_t size)
118{
119 size_t ret = strlen(src);
120
121 if (size) {
122 size_t len = (ret >= size) ? size - 1 : ret;
123 memcpy(dest, src, len);
124 dest[len] = '\0';
125 }
126 return ret;
127}
128#endif
129
wdenkc6097192002-11-03 00:24:07 +0000130#ifndef __HAVE_ARCH_STRCAT
131/**
132 * strcat - Append one %NUL-terminated string to another
133 * @dest: The string to be appended to
134 * @src: The string to append to it
135 */
136char * strcat(char * dest, const char * src)
137{
138 char *tmp = dest;
139
140 while (*dest)
141 dest++;
142 while ((*dest++ = *src++) != '\0')
143 ;
144
145 return tmp;
146}
147#endif
148
149#ifndef __HAVE_ARCH_STRNCAT
150/**
151 * strncat - Append a length-limited, %NUL-terminated string to another
152 * @dest: The string to be appended to
153 * @src: The string to append to it
154 * @count: The maximum numbers of bytes to copy
155 *
156 * Note that in contrast to strncpy, strncat ensures the result is
157 * terminated.
158 */
159char * strncat(char *dest, const char *src, size_t count)
160{
161 char *tmp = dest;
162
163 if (count) {
164 while (*dest)
165 dest++;
166 while ((*dest++ = *src++)) {
167 if (--count == 0) {
168 *dest = '\0';
169 break;
170 }
171 }
172 }
173
174 return tmp;
175}
176#endif
177
178#ifndef __HAVE_ARCH_STRCMP
179/**
180 * strcmp - Compare two strings
181 * @cs: One string
182 * @ct: Another string
183 */
184int strcmp(const char * cs,const char * ct)
185{
186 register signed char __res;
187
188 while (1) {
189 if ((__res = *cs - *ct++) != 0 || !*cs++)
190 break;
191 }
192
193 return __res;
194}
195#endif
196
197#ifndef __HAVE_ARCH_STRNCMP
198/**
199 * strncmp - Compare two length-limited strings
200 * @cs: One string
201 * @ct: Another string
202 * @count: The maximum number of bytes to compare
203 */
204int strncmp(const char * cs,const char * ct,size_t count)
205{
206 register signed char __res = 0;
207
208 while (count) {
209 if ((__res = *cs - *ct++) != 0 || !*cs++)
210 break;
211 count--;
212 }
213
214 return __res;
215}
216#endif
217
218#ifndef __HAVE_ARCH_STRCHR
219/**
220 * strchr - Find the first occurrence of a character in a string
221 * @s: The string to be searched
222 * @c: The character to search for
223 */
224char * strchr(const char * s, int c)
225{
226 for(; *s != (char) c; ++s)
227 if (*s == '\0')
228 return NULL;
229 return (char *) s;
230}
231#endif
232
233#ifndef __HAVE_ARCH_STRRCHR
234/**
235 * strrchr - Find the last occurrence of a character in a string
236 * @s: The string to be searched
237 * @c: The character to search for
238 */
239char * strrchr(const char * s, int c)
240{
241 const char *p = s + strlen(s);
242 do {
wdenk8bde7f72003-06-27 21:31:46 +0000243 if (*p == (char)c)
244 return (char *)p;
wdenkc6097192002-11-03 00:24:07 +0000245 } while (--p >= s);
246 return NULL;
247}
248#endif
249
250#ifndef __HAVE_ARCH_STRLEN
251/**
252 * strlen - Find the length of a string
253 * @s: The string to be sized
254 */
255size_t strlen(const char * s)
256{
257 const char *sc;
258
259 for (sc = s; *sc != '\0'; ++sc)
260 /* nothing */;
261 return sc - s;
262}
263#endif
264
265#ifndef __HAVE_ARCH_STRNLEN
266/**
267 * strnlen - Find the length of a length-limited string
268 * @s: The string to be sized
269 * @count: The maximum number of bytes to search
270 */
271size_t strnlen(const char * s, size_t count)
272{
273 const char *sc;
274
275 for (sc = s; count-- && *sc != '\0'; ++sc)
276 /* nothing */;
277 return sc - s;
278}
279#endif
280
281#ifndef __HAVE_ARCH_STRDUP
282char * strdup(const char *s)
283{
284 char *new;
285
286 if ((s == NULL) ||
287 ((new = malloc (strlen(s) + 1)) == NULL) ) {
288 return NULL;
289 }
290
291 strcpy (new, s);
292 return new;
293}
294#endif
295
296#ifndef __HAVE_ARCH_STRSPN
297/**
298 * strspn - Calculate the length of the initial substring of @s which only
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200299 * contain letters in @accept
wdenkc6097192002-11-03 00:24:07 +0000300 * @s: The string to be searched
301 * @accept: The string to search for
302 */
303size_t strspn(const char *s, const char *accept)
304{
305 const char *p;
306 const char *a;
307 size_t count = 0;
308
309 for (p = s; *p != '\0'; ++p) {
310 for (a = accept; *a != '\0'; ++a) {
311 if (*p == *a)
312 break;
313 }
314 if (*a == '\0')
315 return count;
316 ++count;
317 }
318
319 return count;
320}
321#endif
322
323#ifndef __HAVE_ARCH_STRPBRK
324/**
325 * strpbrk - Find the first occurrence of a set of characters
326 * @cs: The string to be searched
327 * @ct: The characters to search for
328 */
329char * strpbrk(const char * cs,const char * ct)
330{
331 const char *sc1,*sc2;
332
333 for( sc1 = cs; *sc1 != '\0'; ++sc1) {
334 for( sc2 = ct; *sc2 != '\0'; ++sc2) {
335 if (*sc1 == *sc2)
336 return (char *) sc1;
337 }
338 }
339 return NULL;
340}
341#endif
342
343#ifndef __HAVE_ARCH_STRTOK
344/**
345 * strtok - Split a string into tokens
346 * @s: The string to be searched
347 * @ct: The characters to search for
348 *
349 * WARNING: strtok is deprecated, use strsep instead.
350 */
351char * strtok(char * s,const char * ct)
352{
353 char *sbegin, *send;
354
355 sbegin = s ? s : ___strtok;
356 if (!sbegin) {
357 return NULL;
358 }
359 sbegin += strspn(sbegin,ct);
360 if (*sbegin == '\0') {
361 ___strtok = NULL;
362 return( NULL );
363 }
364 send = strpbrk( sbegin, ct);
365 if (send && *send != '\0')
366 *send++ = '\0';
367 ___strtok = send;
368 return (sbegin);
369}
370#endif
371
372#ifndef __HAVE_ARCH_STRSEP
373/**
374 * strsep - Split a string into tokens
375 * @s: The string to be searched
376 * @ct: The characters to search for
377 *
378 * strsep() updates @s to point after the token, ready for the next call.
379 *
380 * It returns empty tokens, too, behaving exactly like the libc function
381 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
382 * Same semantics, slimmer shape. ;)
383 */
384char * strsep(char **s, const char *ct)
385{
386 char *sbegin = *s, *end;
387
388 if (sbegin == NULL)
389 return NULL;
390
391 end = strpbrk(sbegin, ct);
392 if (end)
393 *end++ = '\0';
394 *s = end;
395
396 return sbegin;
397}
398#endif
399
wdenkc3f9d492004-03-14 00:59:59 +0000400#ifndef __HAVE_ARCH_STRSWAB
401/**
402 * strswab - swap adjacent even and odd bytes in %NUL-terminated string
403 * s: address of the string
404 *
405 * returns the address of the swapped string or NULL on error. If
406 * string length is odd, last byte is untouched.
407 */
408char *strswab(const char *s)
409{
Wolfgang Denk389db1f2005-09-25 16:15:17 +0200410 char *p, *q;
wdenkc3f9d492004-03-14 00:59:59 +0000411
412 if ((NULL == s) || ('\0' == *s)) {
413 return (NULL);
414 }
415
Wolfgang Denke5e98ed2005-10-04 23:38:07 +0200416 for (p=(char *)s, q=p+1; (*p != '\0') && (*q != '\0'); p+=2, q+=2) {
wdenkc3f9d492004-03-14 00:59:59 +0000417 char tmp;
Wolfgang Denk389db1f2005-09-25 16:15:17 +0200418
419 tmp = *p;
420 *p = *q;
421 *q = tmp;
wdenkc3f9d492004-03-14 00:59:59 +0000422 }
423
424 return (char *) s;
425}
426#endif
427
wdenkc6097192002-11-03 00:24:07 +0000428#ifndef __HAVE_ARCH_MEMSET
429/**
430 * memset - Fill a region of memory with the given value
431 * @s: Pointer to the start of the area.
432 * @c: The byte to fill the area with
433 * @count: The size of the area.
434 *
435 * Do not use memset() to access IO space, use memset_io() instead.
436 */
437void * memset(void * s,int c,size_t count)
438{
Alessandro Rubinie3ea9482009-10-10 11:51:16 +0200439 unsigned long *sl = (unsigned long *) s;
440 unsigned long cl = 0;
441 char *s8;
442 int i;
wdenkc6097192002-11-03 00:24:07 +0000443
Alessandro Rubinie3ea9482009-10-10 11:51:16 +0200444 /* do it one word at a time (32 bits or 64 bits) while possible */
445 if ( ((ulong)s & (sizeof(*sl) - 1)) == 0) {
446 for (i = 0; i < sizeof(*sl); i++) {
447 cl <<= 8;
448 cl |= c & 0xff;
449 }
450 while (count >= sizeof(*sl)) {
451 *sl++ = cl;
452 count -= sizeof(*sl);
453 }
454 }
455 /* fill 8 bits at a time */
456 s8 = (char *)sl;
wdenkc6097192002-11-03 00:24:07 +0000457 while (count--)
Alessandro Rubinie3ea9482009-10-10 11:51:16 +0200458 *s8++ = c;
wdenkc6097192002-11-03 00:24:07 +0000459
460 return s;
461}
462#endif
463
wdenkc6097192002-11-03 00:24:07 +0000464#ifndef __HAVE_ARCH_MEMCPY
465/**
466 * memcpy - Copy one area of memory to another
467 * @dest: Where to copy to
468 * @src: Where to copy from
469 * @count: The size of the area.
470 *
471 * You should not use this function to access IO space, use memcpy_toio()
472 * or memcpy_fromio() instead.
473 */
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200474void * memcpy(void *dest, const void *src, size_t count)
wdenkc6097192002-11-03 00:24:07 +0000475{
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200476 unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src;
477 char *d8, *s8;
wdenkc6097192002-11-03 00:24:07 +0000478
Matthias Weisserb038db82011-05-22 23:03:55 +0000479 if (src == dest)
480 return dest;
481
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200482 /* while all data is aligned (common case), copy a word at a time */
483 if ( (((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) {
484 while (count >= sizeof(*dl)) {
485 *dl++ = *sl++;
486 count -= sizeof(*dl);
487 }
488 }
489 /* copy the reset one byte at a time */
490 d8 = (char *)dl;
491 s8 = (char *)sl;
wdenkc6097192002-11-03 00:24:07 +0000492 while (count--)
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200493 *d8++ = *s8++;
wdenkc6097192002-11-03 00:24:07 +0000494
495 return dest;
496}
497#endif
498
499#ifndef __HAVE_ARCH_MEMMOVE
500/**
501 * memmove - Copy one area of memory to another
502 * @dest: Where to copy to
503 * @src: Where to copy from
504 * @count: The size of the area.
505 *
506 * Unlike memcpy(), memmove() copes with overlapping areas.
507 */
508void * memmove(void * dest,const void *src,size_t count)
509{
510 char *tmp, *s;
511
Matthias Weisserb038db82011-05-22 23:03:55 +0000512 if (src == dest)
513 return dest;
514
wdenkc6097192002-11-03 00:24:07 +0000515 if (dest <= src) {
516 tmp = (char *) dest;
517 s = (char *) src;
518 while (count--)
519 *tmp++ = *s++;
520 }
521 else {
522 tmp = (char *) dest + count;
523 s = (char *) src + count;
524 while (count--)
525 *--tmp = *--s;
526 }
527
528 return dest;
529}
530#endif
531
532#ifndef __HAVE_ARCH_MEMCMP
533/**
534 * memcmp - Compare two areas of memory
535 * @cs: One area of memory
536 * @ct: Another area of memory
537 * @count: The size of the area.
538 */
539int memcmp(const void * cs,const void * ct,size_t count)
540{
541 const unsigned char *su1, *su2;
542 int res = 0;
543
544 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
545 if ((res = *su1 - *su2) != 0)
546 break;
547 return res;
548}
549#endif
550
551#ifndef __HAVE_ARCH_MEMSCAN
552/**
553 * memscan - Find a character in an area of memory.
554 * @addr: The memory area
555 * @c: The byte to search for
556 * @size: The size of the area.
557 *
558 * returns the address of the first occurrence of @c, or 1 byte past
559 * the area if @c is not found
560 */
561void * memscan(void * addr, int c, size_t size)
562{
563 unsigned char * p = (unsigned char *) addr;
564
565 while (size) {
566 if (*p == c)
567 return (void *) p;
568 p++;
569 size--;
570 }
wdenk8bde7f72003-06-27 21:31:46 +0000571 return (void *) p;
wdenkc6097192002-11-03 00:24:07 +0000572}
573#endif
574
575#ifndef __HAVE_ARCH_STRSTR
576/**
577 * strstr - Find the first substring in a %NUL terminated string
578 * @s1: The string to be searched
579 * @s2: The string to search for
580 */
581char * strstr(const char * s1,const char * s2)
582{
583 int l1, l2;
584
585 l2 = strlen(s2);
586 if (!l2)
587 return (char *) s1;
588 l1 = strlen(s1);
589 while (l1 >= l2) {
590 l1--;
591 if (!memcmp(s1,s2,l2))
592 return (char *) s1;
593 s1++;
594 }
595 return NULL;
596}
597#endif
598
599#ifndef __HAVE_ARCH_MEMCHR
600/**
601 * memchr - Find a character in an area of memory.
602 * @s: The memory area
603 * @c: The byte to search for
604 * @n: The size of the area.
605 *
606 * returns the address of the first occurrence of @c, or %NULL
607 * if @c is not found
608 */
609void *memchr(const void *s, int c, size_t n)
610{
611 const unsigned char *p = s;
612 while (n-- != 0) {
wdenk8bde7f72003-06-27 21:31:46 +0000613 if ((unsigned char)c == *p++) {
wdenkc6097192002-11-03 00:24:07 +0000614 return (void *)(p-1);
615 }
616 }
617 return NULL;
618}
619
620#endif
Sergey Lapindfe64e22013-01-14 03:46:50 +0000621#ifndef __HAVE_ARCH_MEMCHR_INV
622static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
623{
624 while (bytes) {
625 if (*start != value)
626 return (void *)start;
627 start++;
628 bytes--;
629 }
630 return NULL;
631}
632/**
633 * memchr_inv - Find an unmatching character in an area of memory.
634 * @start: The memory area
635 * @c: Find a character other than c
636 * @bytes: The size of the area.
637 *
638 * returns the address of the first character other than @c, or %NULL
639 * if the whole buffer contains just @c.
640 */
641void *memchr_inv(const void *start, int c, size_t bytes)
642{
643 u8 value = c;
644 u64 value64;
645 unsigned int words, prefix;
646
647 if (bytes <= 16)
648 return check_bytes8(start, value, bytes);
649
650 value64 = value;
651 value64 |= value64 << 8;
652 value64 |= value64 << 16;
653 value64 |= value64 << 32;
654
655 prefix = (unsigned long)start % 8;
656 if (prefix) {
657 u8 *r;
658
659 prefix = 8 - prefix;
660 r = check_bytes8(start, value, prefix);
661 if (r)
662 return r;
663 start += prefix;
664 bytes -= prefix;
665 }
666
667 words = bytes / 8;
668
669 while (words) {
670 if (*(u64 *)start != value64)
671 return check_bytes8(start, value, 8);
672 start += 8;
673 words--;
674 }
675
676 return check_bytes8(start, value, bytes % 8);
677}
678#endif