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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
105#ifndef __HAVE_ARCH_STRCAT
106/**
107 * strcat - Append one %NUL-terminated string to another
108 * @dest: The string to be appended to
109 * @src: The string to append to it
110 */
111char * strcat(char * dest, const char * src)
112{
113 char *tmp = dest;
114
115 while (*dest)
116 dest++;
117 while ((*dest++ = *src++) != '\0')
118 ;
119
120 return tmp;
121}
122#endif
123
124#ifndef __HAVE_ARCH_STRNCAT
125/**
126 * strncat - Append a length-limited, %NUL-terminated string to another
127 * @dest: The string to be appended to
128 * @src: The string to append to it
129 * @count: The maximum numbers of bytes to copy
130 *
131 * Note that in contrast to strncpy, strncat ensures the result is
132 * terminated.
133 */
134char * strncat(char *dest, const char *src, size_t count)
135{
136 char *tmp = dest;
137
138 if (count) {
139 while (*dest)
140 dest++;
141 while ((*dest++ = *src++)) {
142 if (--count == 0) {
143 *dest = '\0';
144 break;
145 }
146 }
147 }
148
149 return tmp;
150}
151#endif
152
153#ifndef __HAVE_ARCH_STRCMP
154/**
155 * strcmp - Compare two strings
156 * @cs: One string
157 * @ct: Another string
158 */
159int strcmp(const char * cs,const char * ct)
160{
161 register signed char __res;
162
163 while (1) {
164 if ((__res = *cs - *ct++) != 0 || !*cs++)
165 break;
166 }
167
168 return __res;
169}
170#endif
171
172#ifndef __HAVE_ARCH_STRNCMP
173/**
174 * strncmp - Compare two length-limited strings
175 * @cs: One string
176 * @ct: Another string
177 * @count: The maximum number of bytes to compare
178 */
179int strncmp(const char * cs,const char * ct,size_t count)
180{
181 register signed char __res = 0;
182
183 while (count) {
184 if ((__res = *cs - *ct++) != 0 || !*cs++)
185 break;
186 count--;
187 }
188
189 return __res;
190}
191#endif
192
193#ifndef __HAVE_ARCH_STRCHR
194/**
195 * strchr - Find the first occurrence of a character in a string
196 * @s: The string to be searched
197 * @c: The character to search for
198 */
199char * strchr(const char * s, int c)
200{
201 for(; *s != (char) c; ++s)
202 if (*s == '\0')
203 return NULL;
204 return (char *) s;
205}
206#endif
207
208#ifndef __HAVE_ARCH_STRRCHR
209/**
210 * strrchr - Find the last occurrence of a character in a string
211 * @s: The string to be searched
212 * @c: The character to search for
213 */
214char * strrchr(const char * s, int c)
215{
216 const char *p = s + strlen(s);
217 do {
wdenk8bde7f72003-06-27 21:31:46 +0000218 if (*p == (char)c)
219 return (char *)p;
wdenkc6097192002-11-03 00:24:07 +0000220 } while (--p >= s);
221 return NULL;
222}
223#endif
224
Christian Hitz5454ddb2011-10-12 09:32:05 +0200225
226/**
227 * skip_spaces - Removes leading whitespace from @str.
228 * @str: The string to be stripped.
229 *
230 * Returns a pointer to the first non-whitespace character in @str.
231 */
232char *skip_spaces(const char *str)
233{
234 while (isspace(*str))
235 ++str;
236 return (char *)str;
237}
238
239/**
240 * strim - Removes leading and trailing whitespace from @s.
241 * @s: The string to be stripped.
242 *
243 * Note that the first trailing whitespace is replaced with a %NUL-terminator
244 * in the given string @s. Returns a pointer to the first non-whitespace
245 * character in @s.
246 */
247char *strim(char *s)
248{
249 size_t size;
250 char *end;
251
252 s = skip_spaces(s);
253 size = strlen(s);
254 if (!size)
255 return s;
256
257 end = s + size - 1;
258 while (end >= s && isspace(*end))
259 end--;
260 *(end + 1) = '\0';
261
262 return s;
263}
wdenkc6097192002-11-03 00:24:07 +0000264#ifndef __HAVE_ARCH_STRLEN
265/**
266 * strlen - Find the length of a string
267 * @s: The string to be sized
268 */
269size_t strlen(const char * s)
270{
271 const char *sc;
272
273 for (sc = s; *sc != '\0'; ++sc)
274 /* nothing */;
275 return sc - s;
276}
277#endif
278
279#ifndef __HAVE_ARCH_STRNLEN
280/**
281 * strnlen - Find the length of a length-limited string
282 * @s: The string to be sized
283 * @count: The maximum number of bytes to search
284 */
285size_t strnlen(const char * s, size_t count)
286{
287 const char *sc;
288
289 for (sc = s; count-- && *sc != '\0'; ++sc)
290 /* nothing */;
291 return sc - s;
292}
293#endif
294
295#ifndef __HAVE_ARCH_STRDUP
296char * strdup(const char *s)
297{
298 char *new;
299
300 if ((s == NULL) ||
301 ((new = malloc (strlen(s) + 1)) == NULL) ) {
302 return NULL;
303 }
304
305 strcpy (new, s);
306 return new;
307}
308#endif
309
310#ifndef __HAVE_ARCH_STRSPN
311/**
312 * strspn - Calculate the length of the initial substring of @s which only
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200313 * contain letters in @accept
wdenkc6097192002-11-03 00:24:07 +0000314 * @s: The string to be searched
315 * @accept: The string to search for
316 */
317size_t strspn(const char *s, const char *accept)
318{
319 const char *p;
320 const char *a;
321 size_t count = 0;
322
323 for (p = s; *p != '\0'; ++p) {
324 for (a = accept; *a != '\0'; ++a) {
325 if (*p == *a)
326 break;
327 }
328 if (*a == '\0')
329 return count;
330 ++count;
331 }
332
333 return count;
334}
335#endif
336
337#ifndef __HAVE_ARCH_STRPBRK
338/**
339 * strpbrk - Find the first occurrence of a set of characters
340 * @cs: The string to be searched
341 * @ct: The characters to search for
342 */
343char * strpbrk(const char * cs,const char * ct)
344{
345 const char *sc1,*sc2;
346
347 for( sc1 = cs; *sc1 != '\0'; ++sc1) {
348 for( sc2 = ct; *sc2 != '\0'; ++sc2) {
349 if (*sc1 == *sc2)
350 return (char *) sc1;
351 }
352 }
353 return NULL;
354}
355#endif
356
357#ifndef __HAVE_ARCH_STRTOK
358/**
359 * strtok - Split a string into tokens
360 * @s: The string to be searched
361 * @ct: The characters to search for
362 *
363 * WARNING: strtok is deprecated, use strsep instead.
364 */
365char * strtok(char * s,const char * ct)
366{
367 char *sbegin, *send;
368
369 sbegin = s ? s : ___strtok;
370 if (!sbegin) {
371 return NULL;
372 }
373 sbegin += strspn(sbegin,ct);
374 if (*sbegin == '\0') {
375 ___strtok = NULL;
376 return( NULL );
377 }
378 send = strpbrk( sbegin, ct);
379 if (send && *send != '\0')
380 *send++ = '\0';
381 ___strtok = send;
382 return (sbegin);
383}
384#endif
385
386#ifndef __HAVE_ARCH_STRSEP
387/**
388 * strsep - Split a string into tokens
389 * @s: The string to be searched
390 * @ct: The characters to search for
391 *
392 * strsep() updates @s to point after the token, ready for the next call.
393 *
394 * It returns empty tokens, too, behaving exactly like the libc function
395 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
396 * Same semantics, slimmer shape. ;)
397 */
398char * strsep(char **s, const char *ct)
399{
400 char *sbegin = *s, *end;
401
402 if (sbegin == NULL)
403 return NULL;
404
405 end = strpbrk(sbegin, ct);
406 if (end)
407 *end++ = '\0';
408 *s = end;
409
410 return sbegin;
411}
412#endif
413
wdenkc3f9d492004-03-14 00:59:59 +0000414#ifndef __HAVE_ARCH_STRSWAB
415/**
416 * strswab - swap adjacent even and odd bytes in %NUL-terminated string
417 * s: address of the string
418 *
419 * returns the address of the swapped string or NULL on error. If
420 * string length is odd, last byte is untouched.
421 */
422char *strswab(const char *s)
423{
Wolfgang Denk389db1f2005-09-25 16:15:17 +0200424 char *p, *q;
wdenkc3f9d492004-03-14 00:59:59 +0000425
426 if ((NULL == s) || ('\0' == *s)) {
427 return (NULL);
428 }
429
Wolfgang Denke5e98ed2005-10-04 23:38:07 +0200430 for (p=(char *)s, q=p+1; (*p != '\0') && (*q != '\0'); p+=2, q+=2) {
wdenkc3f9d492004-03-14 00:59:59 +0000431 char tmp;
Wolfgang Denk389db1f2005-09-25 16:15:17 +0200432
433 tmp = *p;
434 *p = *q;
435 *q = tmp;
wdenkc3f9d492004-03-14 00:59:59 +0000436 }
437
438 return (char *) s;
439}
440#endif
441
wdenkc6097192002-11-03 00:24:07 +0000442#ifndef __HAVE_ARCH_MEMSET
443/**
444 * memset - Fill a region of memory with the given value
445 * @s: Pointer to the start of the area.
446 * @c: The byte to fill the area with
447 * @count: The size of the area.
448 *
449 * Do not use memset() to access IO space, use memset_io() instead.
450 */
451void * memset(void * s,int c,size_t count)
452{
Alessandro Rubinie3ea9482009-10-10 11:51:16 +0200453 unsigned long *sl = (unsigned long *) s;
454 unsigned long cl = 0;
455 char *s8;
456 int i;
wdenkc6097192002-11-03 00:24:07 +0000457
Alessandro Rubinie3ea9482009-10-10 11:51:16 +0200458 /* do it one word at a time (32 bits or 64 bits) while possible */
459 if ( ((ulong)s & (sizeof(*sl) - 1)) == 0) {
460 for (i = 0; i < sizeof(*sl); i++) {
461 cl <<= 8;
462 cl |= c & 0xff;
463 }
464 while (count >= sizeof(*sl)) {
465 *sl++ = cl;
466 count -= sizeof(*sl);
467 }
468 }
469 /* fill 8 bits at a time */
470 s8 = (char *)sl;
wdenkc6097192002-11-03 00:24:07 +0000471 while (count--)
Alessandro Rubinie3ea9482009-10-10 11:51:16 +0200472 *s8++ = c;
wdenkc6097192002-11-03 00:24:07 +0000473
474 return s;
475}
476#endif
477
478#ifndef __HAVE_ARCH_BCOPY
479/**
480 * bcopy - Copy one area of memory to another
481 * @src: Where to copy from
482 * @dest: Where to copy to
483 * @count: The size of the area.
484 *
485 * Note that this is the same as memcpy(), with the arguments reversed.
486 * memcpy() is the standard, bcopy() is a legacy BSD function.
487 *
488 * You should not use this function to access IO space, use memcpy_toio()
489 * or memcpy_fromio() instead.
490 */
491char * bcopy(const char * src, char * dest, int count)
492{
493 char *tmp = dest;
494
495 while (count--)
496 *tmp++ = *src++;
497
498 return dest;
499}
500#endif
501
502#ifndef __HAVE_ARCH_MEMCPY
503/**
504 * memcpy - Copy one area of memory to another
505 * @dest: Where to copy to
506 * @src: Where to copy from
507 * @count: The size of the area.
508 *
509 * You should not use this function to access IO space, use memcpy_toio()
510 * or memcpy_fromio() instead.
511 */
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200512void * memcpy(void *dest, const void *src, size_t count)
wdenkc6097192002-11-03 00:24:07 +0000513{
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200514 unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src;
515 char *d8, *s8;
wdenkc6097192002-11-03 00:24:07 +0000516
Matthias Weisserb038db82011-05-22 23:03:55 +0000517 if (src == dest)
518 return dest;
519
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200520 /* while all data is aligned (common case), copy a word at a time */
521 if ( (((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) {
522 while (count >= sizeof(*dl)) {
523 *dl++ = *sl++;
524 count -= sizeof(*dl);
525 }
526 }
527 /* copy the reset one byte at a time */
528 d8 = (char *)dl;
529 s8 = (char *)sl;
wdenkc6097192002-11-03 00:24:07 +0000530 while (count--)
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200531 *d8++ = *s8++;
wdenkc6097192002-11-03 00:24:07 +0000532
533 return dest;
534}
535#endif
536
537#ifndef __HAVE_ARCH_MEMMOVE
538/**
539 * memmove - Copy one area of memory to another
540 * @dest: Where to copy to
541 * @src: Where to copy from
542 * @count: The size of the area.
543 *
544 * Unlike memcpy(), memmove() copes with overlapping areas.
545 */
546void * memmove(void * dest,const void *src,size_t count)
547{
548 char *tmp, *s;
549
Matthias Weisserb038db82011-05-22 23:03:55 +0000550 if (src == dest)
551 return dest;
552
wdenkc6097192002-11-03 00:24:07 +0000553 if (dest <= src) {
554 tmp = (char *) dest;
555 s = (char *) src;
556 while (count--)
557 *tmp++ = *s++;
558 }
559 else {
560 tmp = (char *) dest + count;
561 s = (char *) src + count;
562 while (count--)
563 *--tmp = *--s;
564 }
565
566 return dest;
567}
568#endif
569
570#ifndef __HAVE_ARCH_MEMCMP
571/**
572 * memcmp - Compare two areas of memory
573 * @cs: One area of memory
574 * @ct: Another area of memory
575 * @count: The size of the area.
576 */
577int memcmp(const void * cs,const void * ct,size_t count)
578{
579 const unsigned char *su1, *su2;
580 int res = 0;
581
582 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
583 if ((res = *su1 - *su2) != 0)
584 break;
585 return res;
586}
587#endif
588
589#ifndef __HAVE_ARCH_MEMSCAN
590/**
591 * memscan - Find a character in an area of memory.
592 * @addr: The memory area
593 * @c: The byte to search for
594 * @size: The size of the area.
595 *
596 * returns the address of the first occurrence of @c, or 1 byte past
597 * the area if @c is not found
598 */
599void * memscan(void * addr, int c, size_t size)
600{
601 unsigned char * p = (unsigned char *) addr;
602
603 while (size) {
604 if (*p == c)
605 return (void *) p;
606 p++;
607 size--;
608 }
wdenk8bde7f72003-06-27 21:31:46 +0000609 return (void *) p;
wdenkc6097192002-11-03 00:24:07 +0000610}
611#endif
612
613#ifndef __HAVE_ARCH_STRSTR
614/**
615 * strstr - Find the first substring in a %NUL terminated string
616 * @s1: The string to be searched
617 * @s2: The string to search for
618 */
619char * strstr(const char * s1,const char * s2)
620{
621 int l1, l2;
622
623 l2 = strlen(s2);
624 if (!l2)
625 return (char *) s1;
626 l1 = strlen(s1);
627 while (l1 >= l2) {
628 l1--;
629 if (!memcmp(s1,s2,l2))
630 return (char *) s1;
631 s1++;
632 }
633 return NULL;
634}
635#endif
636
637#ifndef __HAVE_ARCH_MEMCHR
638/**
639 * memchr - Find a character in an area of memory.
640 * @s: The memory area
641 * @c: The byte to search for
642 * @n: The size of the area.
643 *
644 * returns the address of the first occurrence of @c, or %NULL
645 * if @c is not found
646 */
647void *memchr(const void *s, int c, size_t n)
648{
649 const unsigned char *p = s;
650 while (n-- != 0) {
wdenk8bde7f72003-06-27 21:31:46 +0000651 if ((unsigned char)c == *p++) {
wdenkc6097192002-11-03 00:24:07 +0000652 return (void *)(p-1);
653 }
654 }
655 return NULL;
656}
657
658#endif