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 <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
22 #ifndef __HAVE_ARCH_STRNICMP
23 /**
24 * strnicmp - Case insensitive, length-limited string comparison
25 * @s1: One string
26 * @s2: The other string
27 * @len: the maximum number of characters to compare
28 */
strnicmp(const char * s1,const char * s2,size_t len)29 int strnicmp(const char *s1, const char *s2, size_t len)
30 {
31 /* Yes, Virginia, it had better be unsigned */
32 unsigned char c1, c2;
33
34 c1 = 0; c2 = 0;
35 if (len) {
36 do {
37 c1 = *s1; c2 = *s2;
38 s1++; s2++;
39 if (!c1)
40 break;
41 if (!c2)
42 break;
43 if (c1 == c2)
44 continue;
45 c1 = tolower(c1);
46 c2 = tolower(c2);
47 if (c1 != c2)
48 break;
49 } while (--len);
50 }
51 return (int)c1 - (int)c2;
52 }
53 #endif
54
55 char * ___strtok;
56
57 #ifndef __HAVE_ARCH_STRCPY
58 /**
59 * strcpy - Copy a %NUL terminated string
60 * @dest: Where to copy the string to
61 * @src: Where to copy the string from
62 */
strcpy(char * dest,const char * src)63 char * strcpy(char * dest,const char *src)
64 {
65 char *tmp = dest;
66
67 while ((*dest++ = *src++) != '\0')
68 /* nothing */;
69 return tmp;
70 }
71 #endif
72
73 #ifndef __HAVE_ARCH_STRNCPY
74 /**
75 * strncpy - Copy a length-limited, %NUL-terminated string
76 * @dest: Where to copy the string to
77 * @src: Where to copy the string from
78 * @count: The maximum number of bytes to copy
79 *
80 * Note that unlike userspace strncpy, this does not %NUL-pad the buffer.
81 * However, the result is not %NUL-terminated if the source exceeds
82 * @count bytes.
83 */
strncpy(char * dest,const char * src,size_t count)84 char * strncpy(char * dest,const char *src,size_t count)
85 {
86 char *tmp = dest;
87
88 while (count-- && (*dest++ = *src++) != '\0')
89 /* nothing */;
90
91 return tmp;
92 }
93 #endif
94
95 #ifndef __HAVE_ARCH_STRCAT
96 /**
97 * strcat - Append one %NUL-terminated string to another
98 * @dest: The string to be appended to
99 * @src: The string to append to it
100 */
strcat(char * dest,const char * src)101 char * strcat(char * dest, const char * src)
102 {
103 char *tmp = dest;
104
105 while (*dest)
106 dest++;
107 while ((*dest++ = *src++) != '\0')
108 ;
109
110 return tmp;
111 }
112 #endif
113
114 #ifndef __HAVE_ARCH_STRNCAT
115 /**
116 * strncat - Append a length-limited, %NUL-terminated string to another
117 * @dest: The string to be appended to
118 * @src: The string to append to it
119 * @count: The maximum numbers of bytes to copy
120 *
121 * Note that in contrast to strncpy, strncat ensures the result is
122 * terminated.
123 */
strncat(char * dest,const char * src,size_t count)124 char * strncat(char *dest, const char *src, size_t count)
125 {
126 char *tmp = dest;
127
128 if (count) {
129 while (*dest)
130 dest++;
131 while ((*dest++ = *src++)) {
132 if (--count == 0) {
133 *dest = '\0';
134 break;
135 }
136 }
137 }
138
139 return tmp;
140 }
141 #endif
142
143 #ifndef __HAVE_ARCH_STRCMP
144 /**
145 * strcmp - Compare two strings
146 * @cs: One string
147 * @ct: Another string
148 */
strcmp(const char * cs,const char * ct)149 int strcmp(const char * cs,const char * ct)
150 {
151 register signed char __res;
152
153 while (1) {
154 if ((__res = *cs - *ct++) != 0 || !*cs++)
155 break;
156 }
157
158 return __res;
159 }
160 #endif
161
162 #ifndef __HAVE_ARCH_STRNCMP
163 /**
164 * strncmp - Compare two length-limited strings
165 * @cs: One string
166 * @ct: Another string
167 * @count: The maximum number of bytes to compare
168 */
strncmp(const char * cs,const char * ct,size_t count)169 int strncmp(const char * cs,const char * ct,size_t count)
170 {
171 register signed char __res = 0;
172
173 while (count) {
174 if ((__res = *cs - *ct++) != 0 || !*cs++)
175 break;
176 count--;
177 }
178
179 return __res;
180 }
181 #endif
182
183 #ifndef __HAVE_ARCH_STRCHR
184 /**
185 * strchr - Find the first occurrence of a character in a string
186 * @s: The string to be searched
187 * @c: The character to search for
188 */
strchr(const char * s,int c)189 char * strchr(const char * s, int c)
190 {
191 for(; *s != (char) c; ++s)
192 if (*s == '\0')
193 return NULL;
194 return (char *) s;
195 }
196 #endif
197
198 #ifndef __HAVE_ARCH_STRRCHR
199 /**
200 * strrchr - Find the last occurrence of a character in a string
201 * @s: The string to be searched
202 * @c: The character to search for
203 */
strrchr(const char * s,int c)204 char * strrchr(const char * s, int c)
205 {
206 const char *p = s + strlen(s);
207 do {
208 if (*p == (char)c)
209 return (char *)p;
210 } while (--p >= s);
211 return NULL;
212 }
213 #endif
214
215 #ifndef __HAVE_ARCH_STRLEN
216 /**
217 * strlen - Find the length of a string
218 * @s: The string to be sized
219 */
strlen(const char * s)220 size_t strlen(const char * s)
221 {
222 const char *sc;
223
224 for (sc = s; *sc != '\0'; ++sc)
225 /* nothing */;
226 return sc - s;
227 }
228 #endif
229
230 #ifndef __HAVE_ARCH_STRNLEN
231 /**
232 * strnlen - Find the length of a length-limited string
233 * @s: The string to be sized
234 * @count: The maximum number of bytes to search
235 */
strnlen(const char * s,size_t count)236 size_t strnlen(const char * s, size_t count)
237 {
238 const char *sc;
239
240 for (sc = s; count-- && *sc != '\0'; ++sc)
241 /* nothing */;
242 return sc - s;
243 }
244 #endif
245
246 #ifndef __HAVE_ARCH_STRSPN
247 /**
248 * strspn - Calculate the length of the initial substring of @s which only
249 * contain letters in @accept
250 * @s: The string to be searched
251 * @accept: The string to search for
252 */
strspn(const char * s,const char * accept)253 size_t strspn(const char *s, const char *accept)
254 {
255 const char *p;
256 const char *a;
257 size_t count = 0;
258
259 for (p = s; *p != '\0'; ++p) {
260 for (a = accept; *a != '\0'; ++a) {
261 if (*p == *a)
262 break;
263 }
264 if (*a == '\0')
265 return count;
266 ++count;
267 }
268
269 return count;
270 }
271 #endif
272
273 #ifndef __HAVE_ARCH_STRPBRK
274 /**
275 * strpbrk - Find the first occurrence of a set of characters
276 * @cs: The string to be searched
277 * @ct: The characters to search for
278 */
strpbrk(const char * cs,const char * ct)279 char * strpbrk(const char * cs,const char * ct)
280 {
281 const char *sc1,*sc2;
282
283 for( sc1 = cs; *sc1 != '\0'; ++sc1) {
284 for( sc2 = ct; *sc2 != '\0'; ++sc2) {
285 if (*sc1 == *sc2)
286 return (char *) sc1;
287 }
288 }
289 return NULL;
290 }
291 #endif
292
293 #ifndef __HAVE_ARCH_STRTOK
294 /**
295 * strtok - Split a string into tokens
296 * @s: The string to be searched
297 * @ct: The characters to search for
298 *
299 * WARNING: strtok is deprecated, use strsep instead.
300 */
strtok(char * s,const char * ct)301 char * strtok(char * s,const char * ct)
302 {
303 char *sbegin, *send;
304
305 sbegin = s ? s : ___strtok;
306 if (!sbegin) {
307 return NULL;
308 }
309 sbegin += strspn(sbegin,ct);
310 if (*sbegin == '\0') {
311 ___strtok = NULL;
312 return( NULL );
313 }
314 send = strpbrk( sbegin, ct);
315 if (send && *send != '\0')
316 *send++ = '\0';
317 ___strtok = send;
318 return (sbegin);
319 }
320 #endif
321
322 #ifndef __HAVE_ARCH_STRSEP
323 /**
324 * strsep - Split a string into tokens
325 * @s: The string to be searched
326 * @ct: The characters to search for
327 *
328 * strsep() updates @s to point after the token, ready for the next call.
329 *
330 * It returns empty tokens, too, behaving exactly like the libc function
331 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
332 * Same semantics, slimmer shape. ;)
333 */
strsep(char ** s,const char * ct)334 char * strsep(char **s, const char *ct)
335 {
336 char *sbegin = *s, *end;
337
338 if (sbegin == NULL)
339 return NULL;
340
341 end = strpbrk(sbegin, ct);
342 if (end)
343 *end++ = '\0';
344 *s = end;
345
346 return sbegin;
347 }
348 #endif
349
350 #ifndef __HAVE_ARCH_MEMSET
351 /**
352 * memset - Fill a region of memory with the given value
353 * @s: Pointer to the start of the area.
354 * @c: The byte to fill the area with
355 * @count: The size of the area.
356 *
357 * Do not use memset() to access IO space, use memset_io() instead.
358 */
memset(void * s,int c,size_t count)359 void * memset(void * s,int c,size_t count)
360 {
361 char *xs = (char *) s;
362
363 while (count--)
364 *xs++ = c;
365
366 return s;
367 }
368 #endif
369
370 #ifndef __HAVE_ARCH_BCOPY
371 /**
372 * bcopy - Copy one area of memory to another
373 * @src: Where to copy from
374 * @dest: Where to copy to
375 * @count: The size of the area.
376 *
377 * Note that this is the same as memcpy(), with the arguments reversed.
378 * memcpy() is the standard, bcopy() is a legacy BSD function.
379 *
380 * You should not use this function to access IO space, use memcpy_toio()
381 * or memcpy_fromio() instead.
382 */
bcopy(const void * srcp,void * destp,size_t count)383 void bcopy(const void * srcp, void * destp, size_t count)
384 {
385 const char *src = srcp;
386 char *dest = destp;
387
388 while (count--)
389 *dest++ = *src++;
390 }
391 #endif
392
393 #ifndef __HAVE_ARCH_MEMCPY
394 /**
395 * memcpy - Copy one area of memory to another
396 * @dest: Where to copy to
397 * @src: Where to copy from
398 * @count: The size of the area.
399 *
400 * You should not use this function to access IO space, use memcpy_toio()
401 * or memcpy_fromio() instead.
402 */
memcpy(void * dest,const void * src,size_t count)403 void * memcpy(void * dest,const void *src,size_t count)
404 {
405 char *tmp = (char *) dest, *s = (char *) src;
406
407 while (count--)
408 *tmp++ = *s++;
409
410 return dest;
411 }
412 #endif
413
414 #ifndef __HAVE_ARCH_MEMMOVE
415 /**
416 * memmove - Copy one area of memory to another
417 * @dest: Where to copy to
418 * @src: Where to copy from
419 * @count: The size of the area.
420 *
421 * Unlike memcpy(), memmove() copes with overlapping areas.
422 */
memmove(void * dest,const void * src,size_t count)423 void * memmove(void * dest,const void *src,size_t count)
424 {
425 char *tmp, *s;
426
427 if (dest <= src) {
428 tmp = (char *) dest;
429 s = (char *) src;
430 while (count--)
431 *tmp++ = *s++;
432 }
433 else {
434 tmp = (char *) dest + count;
435 s = (char *) src + count;
436 while (count--)
437 *--tmp = *--s;
438 }
439
440 return dest;
441 }
442 #endif
443
444 #ifndef __HAVE_ARCH_MEMCMP
445 /**
446 * memcmp - Compare two areas of memory
447 * @cs: One area of memory
448 * @ct: Another area of memory
449 * @count: The size of the area.
450 */
451 #undef memcmp
memcmp(const void * cs,const void * ct,size_t count)452 int memcmp(const void * cs,const void * ct,size_t count)
453 {
454 const unsigned char *su1, *su2;
455 int res = 0;
456
457 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
458 if ((res = *su1 - *su2) != 0)
459 break;
460 return res;
461 }
462 #endif
463
464 #ifndef __HAVE_ARCH_MEMSCAN
465 /**
466 * memscan - Find a character in an area of memory.
467 * @addr: The memory area
468 * @c: The byte to search for
469 * @size: The size of the area.
470 *
471 * returns the address of the first occurrence of @c, or 1 byte past
472 * the area if @c is not found
473 */
memscan(void * addr,int c,size_t size)474 void * memscan(void * addr, int c, size_t size)
475 {
476 unsigned char * p = (unsigned char *) addr;
477
478 while (size) {
479 if (*p == c)
480 return (void *) p;
481 p++;
482 size--;
483 }
484 return (void *) p;
485 }
486 #endif
487
488 #ifndef __HAVE_ARCH_STRSTR
489 /**
490 * strstr - Find the first substring in a %NUL terminated string
491 * @s1: The string to be searched
492 * @s2: The string to search for
493 */
strstr(const char * s1,const char * s2)494 char * strstr(const char * s1,const char * s2)
495 {
496 int l1, l2;
497
498 l2 = strlen(s2);
499 if (!l2)
500 return (char *) s1;
501 l1 = strlen(s1);
502 while (l1 >= l2) {
503 l1--;
504 if (!memcmp(s1,s2,l2))
505 return (char *) s1;
506 s1++;
507 }
508 return NULL;
509 }
510 #endif
511
512 #ifndef __HAVE_ARCH_MEMCHR
513 /**
514 * memchr - Find a character in an area of memory.
515 * @s: The memory area
516 * @c: The byte to search for
517 * @n: The size of the area.
518 *
519 * returns the address of the first occurrence of @c, or %NULL
520 * if @c is not found
521 */
memchr(const void * s,int c,size_t n)522 void *memchr(const void *s, int c, size_t n)
523 {
524 const unsigned char *p = s;
525 while (n-- != 0) {
526 if ((unsigned char)c == *p++) {
527 return (void *)(p-1);
528 }
529 }
530 return NULL;
531 }
532
533 #endif
534