blob: 2c4f0ec9a11f8e7219b9c5d40659616bf4bc6aaf [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
Wolfgang Denk983bebb2006-05-03 01:00:39 +020024#if 0 /* not used - was: #ifndef __HAVE_ARCH_STRNICMP */
wdenkc6097192002-11-03 00:24:07 +000025/**
26 * strnicmp - Case insensitive, length-limited string comparison
27 * @s1: One string
28 * @s2: The other string
29 * @len: the maximum number of characters to compare
30 */
31int strnicmp(const char *s1, const char *s2, size_t len)
32{
33 /* Yes, Virginia, it had better be unsigned */
34 unsigned char c1, c2;
35
36 c1 = 0; c2 = 0;
37 if (len) {
38 do {
39 c1 = *s1; c2 = *s2;
40 s1++; s2++;
41 if (!c1)
42 break;
43 if (!c2)
44 break;
45 if (c1 == c2)
46 continue;
47 c1 = tolower(c1);
48 c2 = tolower(c2);
49 if (c1 != c2)
50 break;
51 } while (--len);
52 }
53 return (int)c1 - (int)c2;
54}
55#endif
56
57char * ___strtok;
58
59#ifndef __HAVE_ARCH_STRCPY
60/**
61 * strcpy - Copy a %NUL terminated string
62 * @dest: Where to copy the string to
63 * @src: Where to copy the string from
64 */
65char * strcpy(char * dest,const char *src)
66{
67 char *tmp = dest;
68
69 while ((*dest++ = *src++) != '\0')
70 /* nothing */;
71 return tmp;
72}
73#endif
74
75#ifndef __HAVE_ARCH_STRNCPY
76/**
77 * strncpy - Copy a length-limited, %NUL-terminated string
78 * @dest: Where to copy the string to
79 * @src: Where to copy the string from
80 * @count: The maximum number of bytes to copy
81 *
82 * Note that unlike userspace strncpy, this does not %NUL-pad the buffer.
83 * However, the result is not %NUL-terminated if the source exceeds
84 * @count bytes.
85 */
86char * strncpy(char * dest,const char *src,size_t count)
87{
88 char *tmp = dest;
89
90 while (count-- && (*dest++ = *src++) != '\0')
91 /* nothing */;
92
93 return tmp;
94}
95#endif
96
97#ifndef __HAVE_ARCH_STRCAT
98/**
99 * strcat - Append one %NUL-terminated string to another
100 * @dest: The string to be appended to
101 * @src: The string to append to it
102 */
103char * strcat(char * dest, const char * src)
104{
105 char *tmp = dest;
106
107 while (*dest)
108 dest++;
109 while ((*dest++ = *src++) != '\0')
110 ;
111
112 return tmp;
113}
114#endif
115
116#ifndef __HAVE_ARCH_STRNCAT
117/**
118 * strncat - Append a length-limited, %NUL-terminated string to another
119 * @dest: The string to be appended to
120 * @src: The string to append to it
121 * @count: The maximum numbers of bytes to copy
122 *
123 * Note that in contrast to strncpy, strncat ensures the result is
124 * terminated.
125 */
126char * strncat(char *dest, const char *src, size_t count)
127{
128 char *tmp = dest;
129
130 if (count) {
131 while (*dest)
132 dest++;
133 while ((*dest++ = *src++)) {
134 if (--count == 0) {
135 *dest = '\0';
136 break;
137 }
138 }
139 }
140
141 return tmp;
142}
143#endif
144
145#ifndef __HAVE_ARCH_STRCMP
146/**
147 * strcmp - Compare two strings
148 * @cs: One string
149 * @ct: Another string
150 */
151int strcmp(const char * cs,const char * ct)
152{
153 register signed char __res;
154
155 while (1) {
156 if ((__res = *cs - *ct++) != 0 || !*cs++)
157 break;
158 }
159
160 return __res;
161}
162#endif
163
164#ifndef __HAVE_ARCH_STRNCMP
165/**
166 * strncmp - Compare two length-limited strings
167 * @cs: One string
168 * @ct: Another string
169 * @count: The maximum number of bytes to compare
170 */
171int strncmp(const char * cs,const char * ct,size_t count)
172{
173 register signed char __res = 0;
174
175 while (count) {
176 if ((__res = *cs - *ct++) != 0 || !*cs++)
177 break;
178 count--;
179 }
180
181 return __res;
182}
183#endif
184
185#ifndef __HAVE_ARCH_STRCHR
186/**
187 * strchr - Find the first occurrence of a character in a string
188 * @s: The string to be searched
189 * @c: The character to search for
190 */
191char * strchr(const char * s, int c)
192{
193 for(; *s != (char) c; ++s)
194 if (*s == '\0')
195 return NULL;
196 return (char *) s;
197}
198#endif
199
200#ifndef __HAVE_ARCH_STRRCHR
201/**
202 * strrchr - Find the last occurrence of a character in a string
203 * @s: The string to be searched
204 * @c: The character to search for
205 */
206char * strrchr(const char * s, int c)
207{
208 const char *p = s + strlen(s);
209 do {
wdenk8bde7f72003-06-27 21:31:46 +0000210 if (*p == (char)c)
211 return (char *)p;
wdenkc6097192002-11-03 00:24:07 +0000212 } while (--p >= s);
213 return NULL;
214}
215#endif
216
217#ifndef __HAVE_ARCH_STRLEN
218/**
219 * strlen - Find the length of a string
220 * @s: The string to be sized
221 */
222size_t strlen(const char * s)
223{
224 const char *sc;
225
226 for (sc = s; *sc != '\0'; ++sc)
227 /* nothing */;
228 return sc - s;
229}
230#endif
231
232#ifndef __HAVE_ARCH_STRNLEN
233/**
234 * strnlen - Find the length of a length-limited string
235 * @s: The string to be sized
236 * @count: The maximum number of bytes to search
237 */
238size_t strnlen(const char * s, size_t count)
239{
240 const char *sc;
241
242 for (sc = s; count-- && *sc != '\0'; ++sc)
243 /* nothing */;
244 return sc - s;
245}
246#endif
247
248#ifndef __HAVE_ARCH_STRDUP
249char * strdup(const char *s)
250{
251 char *new;
252
253 if ((s == NULL) ||
254 ((new = malloc (strlen(s) + 1)) == NULL) ) {
255 return NULL;
256 }
257
258 strcpy (new, s);
259 return new;
260}
261#endif
262
263#ifndef __HAVE_ARCH_STRSPN
264/**
265 * strspn - Calculate the length of the initial substring of @s which only
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200266 * contain letters in @accept
wdenkc6097192002-11-03 00:24:07 +0000267 * @s: The string to be searched
268 * @accept: The string to search for
269 */
270size_t strspn(const char *s, const char *accept)
271{
272 const char *p;
273 const char *a;
274 size_t count = 0;
275
276 for (p = s; *p != '\0'; ++p) {
277 for (a = accept; *a != '\0'; ++a) {
278 if (*p == *a)
279 break;
280 }
281 if (*a == '\0')
282 return count;
283 ++count;
284 }
285
286 return count;
287}
288#endif
289
290#ifndef __HAVE_ARCH_STRPBRK
291/**
292 * strpbrk - Find the first occurrence of a set of characters
293 * @cs: The string to be searched
294 * @ct: The characters to search for
295 */
296char * strpbrk(const char * cs,const char * ct)
297{
298 const char *sc1,*sc2;
299
300 for( sc1 = cs; *sc1 != '\0'; ++sc1) {
301 for( sc2 = ct; *sc2 != '\0'; ++sc2) {
302 if (*sc1 == *sc2)
303 return (char *) sc1;
304 }
305 }
306 return NULL;
307}
308#endif
309
310#ifndef __HAVE_ARCH_STRTOK
311/**
312 * strtok - Split a string into tokens
313 * @s: The string to be searched
314 * @ct: The characters to search for
315 *
316 * WARNING: strtok is deprecated, use strsep instead.
317 */
318char * strtok(char * s,const char * ct)
319{
320 char *sbegin, *send;
321
322 sbegin = s ? s : ___strtok;
323 if (!sbegin) {
324 return NULL;
325 }
326 sbegin += strspn(sbegin,ct);
327 if (*sbegin == '\0') {
328 ___strtok = NULL;
329 return( NULL );
330 }
331 send = strpbrk( sbegin, ct);
332 if (send && *send != '\0')
333 *send++ = '\0';
334 ___strtok = send;
335 return (sbegin);
336}
337#endif
338
339#ifndef __HAVE_ARCH_STRSEP
340/**
341 * strsep - Split a string into tokens
342 * @s: The string to be searched
343 * @ct: The characters to search for
344 *
345 * strsep() updates @s to point after the token, ready for the next call.
346 *
347 * It returns empty tokens, too, behaving exactly like the libc function
348 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
349 * Same semantics, slimmer shape. ;)
350 */
351char * strsep(char **s, const char *ct)
352{
353 char *sbegin = *s, *end;
354
355 if (sbegin == NULL)
356 return NULL;
357
358 end = strpbrk(sbegin, ct);
359 if (end)
360 *end++ = '\0';
361 *s = end;
362
363 return sbegin;
364}
365#endif
366
wdenkc3f9d492004-03-14 00:59:59 +0000367#ifndef __HAVE_ARCH_STRSWAB
368/**
369 * strswab - swap adjacent even and odd bytes in %NUL-terminated string
370 * s: address of the string
371 *
372 * returns the address of the swapped string or NULL on error. If
373 * string length is odd, last byte is untouched.
374 */
375char *strswab(const char *s)
376{
Wolfgang Denk389db1f2005-09-25 16:15:17 +0200377 char *p, *q;
wdenkc3f9d492004-03-14 00:59:59 +0000378
379 if ((NULL == s) || ('\0' == *s)) {
380 return (NULL);
381 }
382
Wolfgang Denke5e98ed2005-10-04 23:38:07 +0200383 for (p=(char *)s, q=p+1; (*p != '\0') && (*q != '\0'); p+=2, q+=2) {
wdenkc3f9d492004-03-14 00:59:59 +0000384 char tmp;
Wolfgang Denk389db1f2005-09-25 16:15:17 +0200385
386 tmp = *p;
387 *p = *q;
388 *q = tmp;
wdenkc3f9d492004-03-14 00:59:59 +0000389 }
390
391 return (char *) s;
392}
393#endif
394
wdenkc6097192002-11-03 00:24:07 +0000395#ifndef __HAVE_ARCH_MEMSET
396/**
397 * memset - Fill a region of memory with the given value
398 * @s: Pointer to the start of the area.
399 * @c: The byte to fill the area with
400 * @count: The size of the area.
401 *
402 * Do not use memset() to access IO space, use memset_io() instead.
403 */
404void * memset(void * s,int c,size_t count)
405{
Alessandro Rubinie3ea9482009-10-10 11:51:16 +0200406 unsigned long *sl = (unsigned long *) s;
407 unsigned long cl = 0;
408 char *s8;
409 int i;
wdenkc6097192002-11-03 00:24:07 +0000410
Alessandro Rubinie3ea9482009-10-10 11:51:16 +0200411 /* do it one word at a time (32 bits or 64 bits) while possible */
412 if ( ((ulong)s & (sizeof(*sl) - 1)) == 0) {
413 for (i = 0; i < sizeof(*sl); i++) {
414 cl <<= 8;
415 cl |= c & 0xff;
416 }
417 while (count >= sizeof(*sl)) {
418 *sl++ = cl;
419 count -= sizeof(*sl);
420 }
421 }
422 /* fill 8 bits at a time */
423 s8 = (char *)sl;
wdenkc6097192002-11-03 00:24:07 +0000424 while (count--)
Alessandro Rubinie3ea9482009-10-10 11:51:16 +0200425 *s8++ = c;
wdenkc6097192002-11-03 00:24:07 +0000426
427 return s;
428}
429#endif
430
431#ifndef __HAVE_ARCH_BCOPY
432/**
433 * bcopy - Copy one area of memory to another
434 * @src: Where to copy from
435 * @dest: Where to copy to
436 * @count: The size of the area.
437 *
438 * Note that this is the same as memcpy(), with the arguments reversed.
439 * memcpy() is the standard, bcopy() is a legacy BSD function.
440 *
441 * You should not use this function to access IO space, use memcpy_toio()
442 * or memcpy_fromio() instead.
443 */
444char * bcopy(const char * src, char * dest, int count)
445{
446 char *tmp = dest;
447
448 while (count--)
449 *tmp++ = *src++;
450
451 return dest;
452}
453#endif
454
455#ifndef __HAVE_ARCH_MEMCPY
456/**
457 * memcpy - Copy one area of memory to another
458 * @dest: Where to copy to
459 * @src: Where to copy from
460 * @count: The size of the area.
461 *
462 * You should not use this function to access IO space, use memcpy_toio()
463 * or memcpy_fromio() instead.
464 */
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200465void * memcpy(void *dest, const void *src, size_t count)
wdenkc6097192002-11-03 00:24:07 +0000466{
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200467 unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src;
468 char *d8, *s8;
wdenkc6097192002-11-03 00:24:07 +0000469
Matthias Weisserb038db82011-05-22 23:03:55 +0000470 if (src == dest)
471 return dest;
472
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200473 /* while all data is aligned (common case), copy a word at a time */
474 if ( (((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) {
475 while (count >= sizeof(*dl)) {
476 *dl++ = *sl++;
477 count -= sizeof(*dl);
478 }
479 }
480 /* copy the reset one byte at a time */
481 d8 = (char *)dl;
482 s8 = (char *)sl;
wdenkc6097192002-11-03 00:24:07 +0000483 while (count--)
Alessandro Rubiniecd830b2009-10-10 11:51:05 +0200484 *d8++ = *s8++;
wdenkc6097192002-11-03 00:24:07 +0000485
486 return dest;
487}
488#endif
489
490#ifndef __HAVE_ARCH_MEMMOVE
491/**
492 * memmove - Copy one area of memory to another
493 * @dest: Where to copy to
494 * @src: Where to copy from
495 * @count: The size of the area.
496 *
497 * Unlike memcpy(), memmove() copes with overlapping areas.
498 */
499void * memmove(void * dest,const void *src,size_t count)
500{
501 char *tmp, *s;
502
Matthias Weisserb038db82011-05-22 23:03:55 +0000503 if (src == dest)
504 return dest;
505
wdenkc6097192002-11-03 00:24:07 +0000506 if (dest <= src) {
507 tmp = (char *) dest;
508 s = (char *) src;
509 while (count--)
510 *tmp++ = *s++;
511 }
512 else {
513 tmp = (char *) dest + count;
514 s = (char *) src + count;
515 while (count--)
516 *--tmp = *--s;
517 }
518
519 return dest;
520}
521#endif
522
523#ifndef __HAVE_ARCH_MEMCMP
524/**
525 * memcmp - Compare two areas of memory
526 * @cs: One area of memory
527 * @ct: Another area of memory
528 * @count: The size of the area.
529 */
530int memcmp(const void * cs,const void * ct,size_t count)
531{
532 const unsigned char *su1, *su2;
533 int res = 0;
534
535 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
536 if ((res = *su1 - *su2) != 0)
537 break;
538 return res;
539}
540#endif
541
542#ifndef __HAVE_ARCH_MEMSCAN
543/**
544 * memscan - Find a character in an area of memory.
545 * @addr: The memory area
546 * @c: The byte to search for
547 * @size: The size of the area.
548 *
549 * returns the address of the first occurrence of @c, or 1 byte past
550 * the area if @c is not found
551 */
552void * memscan(void * addr, int c, size_t size)
553{
554 unsigned char * p = (unsigned char *) addr;
555
556 while (size) {
557 if (*p == c)
558 return (void *) p;
559 p++;
560 size--;
561 }
wdenk8bde7f72003-06-27 21:31:46 +0000562 return (void *) p;
wdenkc6097192002-11-03 00:24:07 +0000563}
564#endif
565
566#ifndef __HAVE_ARCH_STRSTR
567/**
568 * strstr - Find the first substring in a %NUL terminated string
569 * @s1: The string to be searched
570 * @s2: The string to search for
571 */
572char * strstr(const char * s1,const char * s2)
573{
574 int l1, l2;
575
576 l2 = strlen(s2);
577 if (!l2)
578 return (char *) s1;
579 l1 = strlen(s1);
580 while (l1 >= l2) {
581 l1--;
582 if (!memcmp(s1,s2,l2))
583 return (char *) s1;
584 s1++;
585 }
586 return NULL;
587}
588#endif
589
590#ifndef __HAVE_ARCH_MEMCHR
591/**
592 * memchr - Find a character in an area of memory.
593 * @s: The memory area
594 * @c: The byte to search for
595 * @n: The size of the area.
596 *
597 * returns the address of the first occurrence of @c, or %NULL
598 * if @c is not found
599 */
600void *memchr(const void *s, int c, size_t n)
601{
602 const unsigned char *p = s;
603 while (n-- != 0) {
wdenk8bde7f72003-06-27 21:31:46 +0000604 if ((unsigned char)c == *p++) {
wdenkc6097192002-11-03 00:24:07 +0000605 return (void *)(p-1);
606 }
607 }
608 return NULL;
609}
610
611#endif