projects/linux·blob v2.6.14-rc3 · refs

609 lines · 12.0 KiB

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 <[email protected]>
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 <[email protected]>,
18 * Matthew Hawkins <[email protected]>
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
39 c1 = 0; c2 = 0;
40 if (len) {
41 do {
42 c1 = *s1; c2 = *s2;
43 s1++; s2++;
44 if (!c1)
45 break;
46 if (!c2)
47 break;
48 if (c1 == c2)
49 continue;
50 c1 = tolower(c1);
51 c2 = tolower(c2);
52 if (c1 != c2)
53 break;
54 } while (--len);
55 }
56 return (int)c1 - (int)c2;
57}
58
59EXPORT_SYMBOL(strnicmp);
60#endif
61
62#ifndef __HAVE_ARCH_STRCPY
63/**
64 * strcpy - Copy a %NUL terminated string
65 * @dest: Where to copy the string to
66 * @src: Where to copy the string from
67 */
68#undef strcpy
69char * strcpy(char * dest,const char *src)
70{
71 char *tmp = dest;
72
73 while ((*dest++ = *src++) != '\0')
74 /* nothing */;
75 return tmp;
76}
77EXPORT_SYMBOL(strcpy);
78#endif
79
80#ifndef __HAVE_ARCH_STRNCPY
81/**
82 * strncpy - Copy a length-limited, %NUL-terminated string
83 * @dest: Where to copy the string to
84 * @src: Where to copy the string from
85 * @count: The maximum number of bytes to copy
86 *
87 * The result is not %NUL-terminated if the source exceeds
88 * @count bytes.
89 *
90 * In the case where the length of @src is less than that of
91 * count, the remainder of @dest will be padded with %NUL.
92 *
93 */
94char * strncpy(char * dest,const char *src,size_t count)
95{
96 char *tmp = dest;
97
98 while (count) {
99 if ((*tmp = *src) != 0) src++;
100 tmp++;
101 count--;
102 }
103 return dest;
104}
105EXPORT_SYMBOL(strncpy);
106#endif
107
108#ifndef __HAVE_ARCH_STRLCPY
109/**
110 * strlcpy - Copy a %NUL terminated string into a sized buffer
111 * @dest: Where to copy the string to
112 * @src: Where to copy the string from
113 * @size: size of destination buffer
114 *
115 * Compatible with *BSD: the result is always a valid
116 * NUL-terminated string that fits in the buffer (unless,
117 * of course, the buffer size is zero). It does not pad
118 * out the result like strncpy() does.
119 */
120size_t strlcpy(char *dest, const char *src, size_t size)
121{
122 size_t ret = strlen(src);
123
124 if (size) {
125 size_t len = (ret >= size) ? size-1 : ret;
126 memcpy(dest, src, len);
127 dest[len] = '\0';
128 }
129 return ret;
130}
131EXPORT_SYMBOL(strlcpy);
132#endif
133
134#ifndef __HAVE_ARCH_STRCAT
135/**
136 * strcat - Append one %NUL-terminated string to another
137 * @dest: The string to be appended to
138 * @src: The string to append to it
139 */
140#undef strcat
141char * strcat(char * dest, const char * src)
142{
143 char *tmp = dest;
144
145 while (*dest)
146 dest++;
147 while ((*dest++ = *src++) != '\0')
148 ;
149
150 return tmp;
151}
152EXPORT_SYMBOL(strcat);
153#endif
154
155#ifndef __HAVE_ARCH_STRNCAT
156/**
157 * strncat - Append a length-limited, %NUL-terminated string to another
158 * @dest: The string to be appended to
159 * @src: The string to append to it
160 * @count: The maximum numbers of bytes to copy
161 *
162 * Note that in contrast to strncpy, strncat ensures the result is
163 * terminated.
164 */
165char * strncat(char *dest, const char *src, size_t count)
166{
167 char *tmp = dest;
168
169 if (count) {
170 while (*dest)
171 dest++;
172 while ((*dest++ = *src++) != 0) {
173 if (--count == 0) {
174 *dest = '\0';
175 break;
176 }
177 }
178 }
179
180 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 */
218#undef strcmp
219int strcmp(const char * cs,const char * ct)
220{
221 register signed char __res;
222
223 while (1) {
224 if ((__res = *cs - *ct++) != 0 || !*cs++)
225 break;
226 }
227
228 return __res;
229}
230EXPORT_SYMBOL(strcmp);
231#endif
232
233#ifndef __HAVE_ARCH_STRNCMP
234/**
235 * strncmp - Compare two length-limited strings
236 * @cs: One string
237 * @ct: Another string
238 * @count: The maximum number of bytes to compare
239 */
240int strncmp(const char * cs,const char * ct,size_t count)
241{
242 register signed char __res = 0;
243
244 while (count) {
245 if ((__res = *cs - *ct++) != 0 || !*cs++)
246 break;
247 count--;
248 }
249
250 return __res;
251}
252EXPORT_SYMBOL(strncmp);
253#endif
254
255#ifndef __HAVE_ARCH_STRCHR
256/**
257 * strchr - Find the first occurrence of a character in a string
258 * @s: The string to be searched
259 * @c: The character to search for
260 */
261char * strchr(const char * s, int c)
262{
263 for(; *s != (char) c; ++s)
264 if (*s == '\0')
265 return NULL;
266 return (char *) s;
267}
268EXPORT_SYMBOL(strchr);
269#endif
270
271#ifndef __HAVE_ARCH_STRRCHR
272/**
273 * strrchr - Find the last occurrence of a character in a string
274 * @s: The string to be searched
275 * @c: The character to search for
276 */
277char * strrchr(const char * s, int c)
278{
279 const char *p = s + strlen(s);
280 do {
281 if (*p == (char)c)
282 return (char *)p;
283 } while (--p >= s);
284 return NULL;
285}
286EXPORT_SYMBOL(strrchr);
287#endif
288
289#ifndef __HAVE_ARCH_STRNCHR
290/**
291 * strnchr - Find a character in a length limited string
292 * @s: The string to be searched
293 * @count: The number of characters to be searched
294 * @c: The character to search for
295 */
296char *strnchr(const char *s, size_t count, int c)
297{
298 for (; count-- && *s != '\0'; ++s)
299 if (*s == (char) c)
300 return (char *) s;
301 return NULL;
302}
303EXPORT_SYMBOL(strnchr);
304#endif
305
306#ifndef __HAVE_ARCH_STRLEN
307/**
308 * strlen - Find the length of a string
309 * @s: The string to be sized
310 */
311size_t strlen(const char * s)
312{
313 const char *sc;
314
315 for (sc = s; *sc != '\0'; ++sc)
316 /* nothing */;
317 return sc - s;
318}
319EXPORT_SYMBOL(strlen);
320#endif
321
322#ifndef __HAVE_ARCH_STRNLEN
323/**
324 * strnlen - Find the length of a length-limited string
325 * @s: The string to be sized
326 * @count: The maximum number of bytes to search
327 */
328size_t strnlen(const char * s, size_t count)
329{
330 const char *sc;
331
332 for (sc = s; count-- && *sc != '\0'; ++sc)
333 /* nothing */;
334 return sc - s;
335}
336EXPORT_SYMBOL(strnlen);
337#endif
338
339#ifndef __HAVE_ARCH_STRSPN
340/**
341 * strspn - Calculate the length of the initial substring of @s which only
342 * contain letters in @accept
343 * @s: The string to be searched
344 * @accept: The string to search for
345 */
346size_t strspn(const char *s, const char *accept)
347{
348 const char *p;
349 const char *a;
350 size_t count = 0;
351
352 for (p = s; *p != '\0'; ++p) {
353 for (a = accept; *a != '\0'; ++a) {
354 if (*p == *a)
355 break;
356 }
357 if (*a == '\0')
358 return count;
359 ++count;
360 }
361
362 return count;
363}
364
365EXPORT_SYMBOL(strspn);
366#endif
367
368/**
369 * strcspn - Calculate the length of the initial substring of @s which does
370 * not contain letters in @reject
371 * @s: The string to be searched
372 * @reject: The string to avoid
373 */
374size_t strcspn(const char *s, const char *reject)
375{
376 const char *p;
377 const char *r;
378 size_t count = 0;
379
380 for (p = s; *p != '\0'; ++p) {
381 for (r = reject; *r != '\0'; ++r) {
382 if (*p == *r)
383 return count;
384 }
385 ++count;
386 }
387
388 return count;
389}
390EXPORT_SYMBOL(strcspn);
391
392#ifndef __HAVE_ARCH_STRPBRK
393/**
394 * strpbrk - Find the first occurrence of a set of characters
395 * @cs: The string to be searched
396 * @ct: The characters to search for
397 */
398char * strpbrk(const char * cs,const char * ct)
399{
400 const char *sc1,*sc2;
401
402 for( sc1 = cs; *sc1 != '\0'; ++sc1) {
403 for( sc2 = ct; *sc2 != '\0'; ++sc2) {
404 if (*sc1 == *sc2)
405 return (char *) sc1;
406 }
407 }
408 return NULL;
409}
410EXPORT_SYMBOL(strpbrk);
411#endif
412
413#ifndef __HAVE_ARCH_STRSEP
414/**
415 * strsep - Split a string into tokens
416 * @s: The string to be searched
417 * @ct: The characters to search for
418 *
419 * strsep() updates @s to point after the token, ready for the next call.
420 *
421 * It returns empty tokens, too, behaving exactly like the libc function
422 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
423 * Same semantics, slimmer shape. ;)
424 */
425char * strsep(char **s, const char *ct)
426{
427 char *sbegin = *s, *end;
428
429 if (sbegin == NULL)
430 return NULL;
431
432 end = strpbrk(sbegin, ct);
433 if (end)
434 *end++ = '\0';
435 *s = end;
436
437 return sbegin;
438}
439
440EXPORT_SYMBOL(strsep);
441#endif
442
443#ifndef __HAVE_ARCH_MEMSET
444/**
445 * memset - Fill a region of memory with the given value
446 * @s: Pointer to the start of the area.
447 * @c: The byte to fill the area with
448 * @count: The size of the area.
449 *
450 * Do not use memset() to access IO space, use memset_io() instead.
451 */
452void * memset(void * s,int c,size_t count)
453{
454 char *xs = (char *) s;
455
456 while (count--)
457 *xs++ = c;
458
459 return s;
460}
461EXPORT_SYMBOL(memset);
462#endif
463
464#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 */
474void * memcpy(void * dest,const void *src,size_t count)
475{
476 char *tmp = (char *) dest, *s = (char *) src;
477
478 while (count--)
479 *tmp++ = *s++;
480
481 return dest;
482}
483EXPORT_SYMBOL(memcpy);
484#endif
485
486#ifndef __HAVE_ARCH_MEMMOVE
487/**
488 * memmove - Copy one area of memory to another
489 * @dest: Where to copy to
490 * @src: Where to copy from
491 * @count: The size of the area.
492 *
493 * Unlike memcpy(), memmove() copes with overlapping areas.
494 */
495void * memmove(void * dest,const void *src,size_t count)
496{
497 char *tmp, *s;
498
499 if (dest <= src) {
500 tmp = (char *) dest;
501 s = (char *) src;
502 while (count--)
503 *tmp++ = *s++;
504 }
505 else {
506 tmp = (char *) dest + count;
507 s = (char *) src + count;
508 while (count--)
509 *--tmp = *--s;
510 }
511
512 return dest;
513}
514EXPORT_SYMBOL(memmove);
515#endif
516
517#ifndef __HAVE_ARCH_MEMCMP
518/**
519 * memcmp - Compare two areas of memory
520 * @cs: One area of memory
521 * @ct: Another area of memory
522 * @count: The size of the area.
523 */
524#undef memcmp
525int memcmp(const void * cs,const void * ct,size_t count)
526{
527 const unsigned char *su1, *su2;
528 int res = 0;
529
530 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
531 if ((res = *su1 - *su2) != 0)
532 break;
533 return res;
534}
535EXPORT_SYMBOL(memcmp);
536#endif
537
538#ifndef __HAVE_ARCH_MEMSCAN
539/**
540 * memscan - Find a character in an area of memory.
541 * @addr: The memory area
542 * @c: The byte to search for
543 * @size: The size of the area.
544 *
545 * returns the address of the first occurrence of @c, or 1 byte past
546 * the area if @c is not found
547 */
548void * memscan(void * addr, int c, size_t size)
549{
550 unsigned char * p = (unsigned char *) addr;
551
552 while (size) {
553 if (*p == c)
554 return (void *) p;
555 p++;
556 size--;
557 }
558 return (void *) p;
559}
560EXPORT_SYMBOL(memscan);
561#endif
562
563#ifndef __HAVE_ARCH_STRSTR
564/**
565 * strstr - Find the first substring in a %NUL terminated string
566 * @s1: The string to be searched
567 * @s2: The string to search for
568 */
569char * strstr(const char * s1,const char * s2)
570{
571 int l1, l2;
572
573 l2 = strlen(s2);
574 if (!l2)
575 return (char *) s1;
576 l1 = strlen(s1);
577 while (l1 >= l2) {
578 l1--;
579 if (!memcmp(s1,s2,l2))
580 return (char *) s1;
581 s1++;
582 }
583 return NULL;
584}
585EXPORT_SYMBOL(strstr);
586#endif
587
588#ifndef __HAVE_ARCH_MEMCHR
589/**
590 * memchr - Find a character in an area of memory.
591 * @s: The memory area
592 * @c: The byte to search for
593 * @n: The size of the area.
594 *
595 * returns the address of the first occurrence of @c, or %NULL
596 * if @c is not found
597 */
598void *memchr(const void *s, int c, size_t n)
599{
600 const unsigned char *p = s;
601 while (n-- != 0) {
602 if ((unsigned char)c == *p++) {
603 return (void *)(p-1);
604 }
605 }
606 return NULL;
607}
608EXPORT_SYMBOL(memchr);
609#endif