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 * * Sat Feb 09 2002, Jason Thomas <jason@topic.com.au>, 18 * Matthew Hawkins <matt@mh.dropbear.id.au> 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 */ 34 int 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 59 EXPORT_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 char * strcpy(char * dest,const char *src) 69 { 70 char *tmp = dest; 71 72 while ((*dest++ = *src++) != '\0') 73 /* nothing */; 74 return tmp; 75 } 76 EXPORT_SYMBOL(strcpy); 77 #endif 78 79 #ifndef __HAVE_ARCH_STRNCPY 80 /** 81 * strncpy - Copy a length-limited, %NUL-terminated string 82 * @dest: Where to copy the string to 83 * @src: Where to copy the string from 84 * @count: The maximum number of bytes to copy 85 * 86 * The result is not %NUL-terminated if the source exceeds 87 * @count bytes. 88 */ 89 char * strncpy(char * dest,const char *src,size_t count) 90 { 91 char *tmp = dest; 92 93 while (count) { 94 if ((*tmp = *src) != 0) src++; 95 tmp++; 96 count--; 97 } 98 return dest; 99 } 100 EXPORT_SYMBOL(strncpy); 101 #endif 102 103 #ifndef __HAVE_ARCH_STRLCPY 104 /** 105 * strlcpy - Copy a %NUL terminated string into a sized buffer 106 * @dest: Where to copy the string to 107 * @src: Where to copy the string from 108 * @size: size of destination buffer 109 * 110 * Compatible with *BSD: the result is always a valid 111 * NUL-terminated string that fits in the buffer (unless, 112 * of course, the buffer size is zero). It does not pad 113 * out the result like strncpy() does. 114 */ 115 size_t strlcpy(char *dest, const char *src, size_t size) 116 { 117 size_t ret = strlen(src); 118 119 if (size) { 120 size_t len = (ret >= size) ? size-1 : ret; 121 memcpy(dest, src, len); 122 dest[len] = '\0'; 123 } 124 return ret; 125 } 126 EXPORT_SYMBOL(strlcpy); 127 #endif 128 129 #ifndef __HAVE_ARCH_STRCAT 130 /** 131 * strcat - Append one %NUL-terminated string to another 132 * @dest: The string to be appended to 133 * @src: The string to append to it 134 */ 135 char * strcat(char * dest, const char * src) 136 { 137 char *tmp = dest; 138 139 while (*dest) 140 dest++; 141 while ((*dest++ = *src++) != '\0') 142 ; 143 144 return tmp; 145 } 146 EXPORT_SYMBOL(strcat); 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 */ 159 char * 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++) != 0) { 167 if (--count == 0) { 168 *dest = '\0'; 169 break; 170 } 171 } 172 } 173 174 return tmp; 175 } 176 EXPORT_SYMBOL(strncat); 177 #endif 178 179 #ifndef __HAVE_ARCH_STRLCAT 180 /** 181 * strlcat - Append a length-limited, %NUL-terminated string to another 182 * @dest: The string to be appended to 183 * @src: The string to append to it 184 * @count: The size of the destination buffer. 185 */ 186 size_t strlcat(char *dest, const char *src, size_t count) 187 { 188 size_t dsize = strlen(dest); 189 size_t len = strlen(src); 190 size_t res = dsize + len; 191 192 /* This would be a bug */ 193 BUG_ON(dsize >= count); 194 195 dest += dsize; 196 count -= dsize; 197 if (len >= count) 198 len = count-1; 199 memcpy(dest, src, len); 200 dest[len] = 0; 201 return res; 202 } 203 EXPORT_SYMBOL(strlcat); 204 #endif 205 206 #ifndef __HAVE_ARCH_STRCMP 207 /** 208 * strcmp - Compare two strings 209 * @cs: One string 210 * @ct: Another string 211 */ 212 int strcmp(const char * cs,const char * ct) 213 { 214 register signed char __res; 215 216 while (1) { 217 if ((__res = *cs - *ct++) != 0 || !*cs++) 218 break; 219 } 220 221 return __res; 222 } 223 EXPORT_SYMBOL(strcmp); 224 #endif 225 226 #ifndef __HAVE_ARCH_STRNCMP 227 /** 228 * strncmp - Compare two length-limited strings 229 * @cs: One string 230 * @ct: Another string 231 * @count: The maximum number of bytes to compare 232 */ 233 int strncmp(const char * cs,const char * ct,size_t count) 234 { 235 register signed char __res = 0; 236 237 while (count) { 238 if ((__res = *cs - *ct++) != 0 || !*cs++) 239 break; 240 count--; 241 } 242 243 return __res; 244 } 245 EXPORT_SYMBOL(strncmp); 246 #endif 247 248 #ifndef __HAVE_ARCH_STRCHR 249 /** 250 * strchr - Find the first occurrence of a character in a string 251 * @s: The string to be searched 252 * @c: The character to search for 253 */ 254 char * strchr(const char * s, int c) 255 { 256 for(; *s != (char) c; ++s) 257 if (*s == '\0') 258 return NULL; 259 return (char *) s; 260 } 261 EXPORT_SYMBOL(strchr); 262 #endif 263 264 #ifndef __HAVE_ARCH_STRRCHR 265 /** 266 * strrchr - Find the last occurrence of a character in a string 267 * @s: The string to be searched 268 * @c: The character to search for 269 */ 270 char * strrchr(const char * s, int c) 271 { 272 const char *p = s + strlen(s); 273 do { 274 if (*p == (char)c) 275 return (char *)p; 276 } while (--p >= s); 277 return NULL; 278 } 279 EXPORT_SYMBOL(strrchr); 280 #endif 281 282 #ifndef __HAVE_ARCH_STRNCHR 283 /** 284 * strnchr - Find a character in a length limited string 285 * @s: The string to be searched 286 * @count: The number of characters to be searched 287 * @c: The character to search for 288 */ 289 char *strnchr(const char *s, size_t count, int c) 290 { 291 for (; count-- && *s != '\0'; ++s) 292 if (*s == (char) c) 293 return (char *) s; 294 return NULL; 295 } 296 EXPORT_SYMBOL(strnchr); 297 #endif 298 299 #ifndef __HAVE_ARCH_STRLEN 300 /** 301 * strlen - Find the length of a string 302 * @s: The string to be sized 303 */ 304 size_t strlen(const char * s) 305 { 306 const char *sc; 307 308 for (sc = s; *sc != '\0'; ++sc) 309 /* nothing */; 310 return sc - s; 311 } 312 EXPORT_SYMBOL(strlen); 313 #endif 314 315 #ifndef __HAVE_ARCH_STRNLEN 316 /** 317 * strnlen - Find the length of a length-limited string 318 * @s: The string to be sized 319 * @count: The maximum number of bytes to search 320 */ 321 size_t strnlen(const char * s, size_t count) 322 { 323 const char *sc; 324 325 for (sc = s; count-- && *sc != '\0'; ++sc) 326 /* nothing */; 327 return sc - s; 328 } 329 EXPORT_SYMBOL(strnlen); 330 #endif 331 332 #ifndef __HAVE_ARCH_STRSPN 333 /** 334 * strspn - Calculate the length of the initial substring of @s which only 335 * contain letters in @accept 336 * @s: The string to be searched 337 * @accept: The string to search for 338 */ 339 size_t strspn(const char *s, const char *accept) 340 { 341 const char *p; 342 const char *a; 343 size_t count = 0; 344 345 for (p = s; *p != '\0'; ++p) { 346 for (a = accept; *a != '\0'; ++a) { 347 if (*p == *a) 348 break; 349 } 350 if (*a == '\0') 351 return count; 352 ++count; 353 } 354 355 return count; 356 } 357 358 EXPORT_SYMBOL(strspn); 359 #endif 360 361 /** 362 * strcspn - Calculate the length of the initial substring of @s which does 363 * not contain letters in @reject 364 * @s: The string to be searched 365 * @reject: The string to avoid 366 */ 367 size_t strcspn(const char *s, const char *reject) 368 { 369 const char *p; 370 const char *r; 371 size_t count = 0; 372 373 for (p = s; *p != '\0'; ++p) { 374 for (r = reject; *r != '\0'; ++r) { 375 if (*p == *r) 376 return count; 377 } 378 ++count; 379 } 380 381 return count; 382 } 383 EXPORT_SYMBOL(strcspn); 384 385 #ifndef __HAVE_ARCH_STRPBRK 386 /** 387 * strpbrk - Find the first occurrence of a set of characters 388 * @cs: The string to be searched 389 * @ct: The characters to search for 390 */ 391 char * strpbrk(const char * cs,const char * ct) 392 { 393 const char *sc1,*sc2; 394 395 for( sc1 = cs; *sc1 != '\0'; ++sc1) { 396 for( sc2 = ct; *sc2 != '\0'; ++sc2) { 397 if (*sc1 == *sc2) 398 return (char *) sc1; 399 } 400 } 401 return NULL; 402 } 403 EXPORT_SYMBOL(strpbrk); 404 #endif 405 406 #ifndef __HAVE_ARCH_STRSEP 407 /** 408 * strsep - Split a string into tokens 409 * @s: The string to be searched 410 * @ct: The characters to search for 411 * 412 * strsep() updates @s to point after the token, ready for the next call. 413 * 414 * It returns empty tokens, too, behaving exactly like the libc function 415 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. 416 * Same semantics, slimmer shape. ;) 417 */ 418 char * strsep(char **s, const char *ct) 419 { 420 char *sbegin = *s, *end; 421 422 if (sbegin == NULL) 423 return NULL; 424 425 end = strpbrk(sbegin, ct); 426 if (end) 427 *end++ = '\0'; 428 *s = end; 429 430 return sbegin; 431 } 432 433 EXPORT_SYMBOL(strsep); 434 #endif 435 436 #ifndef __HAVE_ARCH_MEMSET 437 /** 438 * memset - Fill a region of memory with the given value 439 * @s: Pointer to the start of the area. 440 * @c: The byte to fill the area with 441 * @count: The size of the area. 442 * 443 * Do not use memset() to access IO space, use memset_io() instead. 444 */ 445 void * memset(void * s,int c,size_t count) 446 { 447 char *xs = (char *) s; 448 449 while (count--) 450 *xs++ = c; 451 452 return s; 453 } 454 EXPORT_SYMBOL(memset); 455 #endif 456 457 #ifndef __HAVE_ARCH_MEMCPY 458 /** 459 * memcpy - Copy one area of memory to another 460 * @dest: Where to copy to 461 * @src: Where to copy from 462 * @count: The size of the area. 463 * 464 * You should not use this function to access IO space, use memcpy_toio() 465 * or memcpy_fromio() instead. 466 */ 467 void * memcpy(void * dest,const void *src,size_t count) 468 { 469 char *tmp = (char *) dest, *s = (char *) src; 470 471 while (count--) 472 *tmp++ = *s++; 473 474 return dest; 475 } 476 EXPORT_SYMBOL(memcpy); 477 #endif 478 479 #ifndef __HAVE_ARCH_MEMMOVE 480 /** 481 * memmove - Copy one area of memory to another 482 * @dest: Where to copy to 483 * @src: Where to copy from 484 * @count: The size of the area. 485 * 486 * Unlike memcpy(), memmove() copes with overlapping areas. 487 */ 488 void * memmove(void * dest,const void *src,size_t count) 489 { 490 char *tmp, *s; 491 492 if (dest <= src) { 493 tmp = (char *) dest; 494 s = (char *) src; 495 while (count--) 496 *tmp++ = *s++; 497 } 498 else { 499 tmp = (char *) dest + count; 500 s = (char *) src + count; 501 while (count--) 502 *--tmp = *--s; 503 } 504 505 return dest; 506 } 507 EXPORT_SYMBOL(memmove); 508 #endif 509 510 #ifndef __HAVE_ARCH_MEMCMP 511 /** 512 * memcmp - Compare two areas of memory 513 * @cs: One area of memory 514 * @ct: Another area of memory 515 * @count: The size of the area. 516 */ 517 int memcmp(const void * cs,const void * ct,size_t count) 518 { 519 const unsigned char *su1, *su2; 520 int res = 0; 521 522 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) 523 if ((res = *su1 - *su2) != 0) 524 break; 525 return res; 526 } 527 EXPORT_SYMBOL(memcmp); 528 #endif 529 530 #ifndef __HAVE_ARCH_MEMSCAN 531 /** 532 * memscan - Find a character in an area of memory. 533 * @addr: The memory area 534 * @c: The byte to search for 535 * @size: The size of the area. 536 * 537 * returns the address of the first occurrence of @c, or 1 byte past 538 * the area if @c is not found 539 */ 540 void * memscan(void * addr, int c, size_t size) 541 { 542 unsigned char * p = (unsigned char *) addr; 543 544 while (size) { 545 if (*p == c) 546 return (void *) p; 547 p++; 548 size--; 549 } 550 return (void *) p; 551 } 552 EXPORT_SYMBOL(memscan); 553 #endif 554 555 #ifndef __HAVE_ARCH_STRSTR 556 /** 557 * strstr - Find the first substring in a %NUL terminated string 558 * @s1: The string to be searched 559 * @s2: The string to search for 560 */ 561 char * strstr(const char * s1,const char * s2) 562 { 563 int l1, l2; 564 565 l2 = strlen(s2); 566 if (!l2) 567 return (char *) s1; 568 l1 = strlen(s1); 569 while (l1 >= l2) { 570 l1--; 571 if (!memcmp(s1,s2,l2)) 572 return (char *) s1; 573 s1++; 574 } 575 return NULL; 576 } 577 EXPORT_SYMBOL(strstr); 578 #endif 579 580 #ifndef __HAVE_ARCH_MEMCHR 581 /** 582 * memchr - Find a character in an area of memory. 583 * @s: The memory area 584 * @c: The byte to search for 585 * @n: The size of the area. 586 * 587 * returns the address of the first occurrence of @c, or %NULL 588 * if @c is not found 589 */ 590 void *memchr(const void *s, int c, size_t n) 591 { 592 const unsigned char *p = s; 593 while (n-- != 0) { 594 if ((unsigned char)c == *p++) { 595 return (void *)(p-1); 596 } 597 } 598 return NULL; 599 } 600 EXPORT_SYMBOL(memchr); 601 #endif 602