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 = c2 = 0; 40 if (len) { 41 do { 42 c1 = *s1; 43 c2 = *s2; 44 s1++; 45 s2++; 46 if (!c1) 47 break; 48 if (!c2) 49 break; 50 if (c1 == c2) 51 continue; 52 c1 = tolower(c1); 53 c2 = tolower(c2); 54 if (c1 != c2) 55 break; 56 } while (--len); 57 } 58 return (int)c1 - (int)c2; 59 } 60 EXPORT_SYMBOL(strnicmp); 61 #endif 62 63 #ifndef __HAVE_ARCH_STRCASECMP 64 int strcasecmp(const char *s1, const char *s2) 65 { 66 int c1, c2; 67 68 do { 69 c1 = tolower(*s1++); 70 c2 = tolower(*s2++); 71 } while (c1 == c2 && c1 != 0); 72 return c1 - c2; 73 } 74 EXPORT_SYMBOL(strcasecmp); 75 #endif 76 77 #ifndef __HAVE_ARCH_STRNCASECMP 78 int strncasecmp(const char *s1, const char *s2, size_t n) 79 { 80 int c1, c2; 81 82 do { 83 c1 = tolower(*s1++); 84 c2 = tolower(*s2++); 85 } while ((--n > 0) && c1 == c2 && c1 != 0); 86 return c1 - c2; 87 } 88 EXPORT_SYMBOL(strncasecmp); 89 #endif 90 91 #ifndef __HAVE_ARCH_STRCPY 92 /** 93 * strcpy - Copy a %NUL terminated string 94 * @dest: Where to copy the string to 95 * @src: Where to copy the string from 96 */ 97 #undef strcpy 98 char *strcpy(char *dest, const char *src) 99 { 100 char *tmp = dest; 101 102 while ((*dest++ = *src++) != '\0') 103 /* nothing */; 104 return tmp; 105 } 106 EXPORT_SYMBOL(strcpy); 107 #endif 108 109 #ifndef __HAVE_ARCH_STRNCPY 110 /** 111 * strncpy - Copy a length-limited, %NUL-terminated string 112 * @dest: Where to copy the string to 113 * @src: Where to copy the string from 114 * @count: The maximum number of bytes to copy 115 * 116 * The result is not %NUL-terminated if the source exceeds 117 * @count bytes. 118 * 119 * In the case where the length of @src is less than that of 120 * count, the remainder of @dest will be padded with %NUL. 121 * 122 */ 123 char *strncpy(char *dest, const char *src, size_t count) 124 { 125 char *tmp = dest; 126 127 while (count) { 128 if ((*tmp = *src) != 0) 129 src++; 130 tmp++; 131 count--; 132 } 133 return dest; 134 } 135 EXPORT_SYMBOL(strncpy); 136 #endif 137 138 #ifndef __HAVE_ARCH_STRLCPY 139 /** 140 * strlcpy - Copy a %NUL terminated string into a sized buffer 141 * @dest: Where to copy the string to 142 * @src: Where to copy the string from 143 * @size: size of destination buffer 144 * 145 * Compatible with *BSD: the result is always a valid 146 * NUL-terminated string that fits in the buffer (unless, 147 * of course, the buffer size is zero). It does not pad 148 * out the result like strncpy() does. 149 */ 150 size_t strlcpy(char *dest, const char *src, size_t size) 151 { 152 size_t ret = strlen(src); 153 154 if (size) { 155 size_t len = (ret >= size) ? size - 1 : ret; 156 memcpy(dest, src, len); 157 dest[len] = '\0'; 158 } 159 return ret; 160 } 161 EXPORT_SYMBOL(strlcpy); 162 #endif 163 164 #ifndef __HAVE_ARCH_STRCAT 165 /** 166 * strcat - Append one %NUL-terminated string to another 167 * @dest: The string to be appended to 168 * @src: The string to append to it 169 */ 170 #undef strcat 171 char *strcat(char *dest, const char *src) 172 { 173 char *tmp = dest; 174 175 while (*dest) 176 dest++; 177 while ((*dest++ = *src++) != '\0') 178 ; 179 return tmp; 180 } 181 EXPORT_SYMBOL(strcat); 182 #endif 183 184 #ifndef __HAVE_ARCH_STRNCAT 185 /** 186 * strncat - Append a length-limited, %NUL-terminated string to another 187 * @dest: The string to be appended to 188 * @src: The string to append to it 189 * @count: The maximum numbers of bytes to copy 190 * 191 * Note that in contrast to strncpy(), strncat() ensures the result is 192 * terminated. 193 */ 194 char *strncat(char *dest, const char *src, size_t count) 195 { 196 char *tmp = dest; 197 198 if (count) { 199 while (*dest) 200 dest++; 201 while ((*dest++ = *src++) != 0) { 202 if (--count == 0) { 203 *dest = '\0'; 204 break; 205 } 206 } 207 } 208 return tmp; 209 } 210 EXPORT_SYMBOL(strncat); 211 #endif 212 213 #ifndef __HAVE_ARCH_STRLCAT 214 /** 215 * strlcat - Append a length-limited, %NUL-terminated string to another 216 * @dest: The string to be appended to 217 * @src: The string to append to it 218 * @count: The size of the destination buffer. 219 */ 220 size_t strlcat(char *dest, const char *src, size_t count) 221 { 222 size_t dsize = strlen(dest); 223 size_t len = strlen(src); 224 size_t res = dsize + len; 225 226 /* This would be a bug */ 227 BUG_ON(dsize >= count); 228 229 dest += dsize; 230 count -= dsize; 231 if (len >= count) 232 len = count-1; 233 memcpy(dest, src, len); 234 dest[len] = 0; 235 return res; 236 } 237 EXPORT_SYMBOL(strlcat); 238 #endif 239 240 #ifndef __HAVE_ARCH_STRCMP 241 /** 242 * strcmp - Compare two strings 243 * @cs: One string 244 * @ct: Another string 245 */ 246 #undef strcmp 247 int strcmp(const char *cs, const char *ct) 248 { 249 signed char __res; 250 251 while (1) { 252 if ((__res = *cs - *ct++) != 0 || !*cs++) 253 break; 254 } 255 return __res; 256 } 257 EXPORT_SYMBOL(strcmp); 258 #endif 259 260 #ifndef __HAVE_ARCH_STRNCMP 261 /** 262 * strncmp - Compare two length-limited strings 263 * @cs: One string 264 * @ct: Another string 265 * @count: The maximum number of bytes to compare 266 */ 267 int strncmp(const char *cs, const char *ct, size_t count) 268 { 269 signed char __res = 0; 270 271 while (count) { 272 if ((__res = *cs - *ct++) != 0 || !*cs++) 273 break; 274 count--; 275 } 276 return __res; 277 } 278 EXPORT_SYMBOL(strncmp); 279 #endif 280 281 #ifndef __HAVE_ARCH_STRCHR 282 /** 283 * strchr - Find the first occurrence of a character in a string 284 * @s: The string to be searched 285 * @c: The character to search for 286 */ 287 char *strchr(const char *s, int c) 288 { 289 for (; *s != (char)c; ++s) 290 if (*s == '\0') 291 return NULL; 292 return (char *)s; 293 } 294 EXPORT_SYMBOL(strchr); 295 #endif 296 297 #ifndef __HAVE_ARCH_STRRCHR 298 /** 299 * strrchr - Find the last occurrence of a character in a string 300 * @s: The string to be searched 301 * @c: The character to search for 302 */ 303 char *strrchr(const char *s, int c) 304 { 305 const char *p = s + strlen(s); 306 do { 307 if (*p == (char)c) 308 return (char *)p; 309 } while (--p >= s); 310 return NULL; 311 } 312 EXPORT_SYMBOL(strrchr); 313 #endif 314 315 #ifndef __HAVE_ARCH_STRNCHR 316 /** 317 * strnchr - Find a character in a length limited string 318 * @s: The string to be searched 319 * @count: The number of characters to be searched 320 * @c: The character to search for 321 */ 322 char *strnchr(const char *s, size_t count, int c) 323 { 324 for (; count-- && *s != '\0'; ++s) 325 if (*s == (char)c) 326 return (char *)s; 327 return NULL; 328 } 329 EXPORT_SYMBOL(strnchr); 330 #endif 331 332 /** 333 * strstrip - Removes leading and trailing whitespace from @s. 334 * @s: The string to be stripped. 335 * 336 * Note that the first trailing whitespace is replaced with a %NUL-terminator 337 * in the given string @s. Returns a pointer to the first non-whitespace 338 * character in @s. 339 */ 340 char *strstrip(char *s) 341 { 342 size_t size; 343 char *end; 344 345 size = strlen(s); 346 347 if (!size) 348 return s; 349 350 end = s + size - 1; 351 while (end >= s && isspace(*end)) 352 end--; 353 *(end + 1) = '\0'; 354 355 while (*s && isspace(*s)) 356 s++; 357 358 return s; 359 } 360 EXPORT_SYMBOL(strstrip); 361 362 #ifndef __HAVE_ARCH_STRLEN 363 /** 364 * strlen - Find the length of a string 365 * @s: The string to be sized 366 */ 367 size_t strlen(const char *s) 368 { 369 const char *sc; 370 371 for (sc = s; *sc != '\0'; ++sc) 372 /* nothing */; 373 return sc - s; 374 } 375 EXPORT_SYMBOL(strlen); 376 #endif 377 378 #ifndef __HAVE_ARCH_STRNLEN 379 /** 380 * strnlen - Find the length of a length-limited string 381 * @s: The string to be sized 382 * @count: The maximum number of bytes to search 383 */ 384 size_t strnlen(const char *s, size_t count) 385 { 386 const char *sc; 387 388 for (sc = s; count-- && *sc != '\0'; ++sc) 389 /* nothing */; 390 return sc - s; 391 } 392 EXPORT_SYMBOL(strnlen); 393 #endif 394 395 #ifndef __HAVE_ARCH_STRSPN 396 /** 397 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept 398 * @s: The string to be searched 399 * @accept: The string to search for 400 */ 401 size_t strspn(const char *s, const char *accept) 402 { 403 const char *p; 404 const char *a; 405 size_t count = 0; 406 407 for (p = s; *p != '\0'; ++p) { 408 for (a = accept; *a != '\0'; ++a) { 409 if (*p == *a) 410 break; 411 } 412 if (*a == '\0') 413 return count; 414 ++count; 415 } 416 return count; 417 } 418 419 EXPORT_SYMBOL(strspn); 420 #endif 421 422 #ifndef __HAVE_ARCH_STRCSPN 423 /** 424 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject 425 * @s: The string to be searched 426 * @reject: The string to avoid 427 */ 428 size_t strcspn(const char *s, const char *reject) 429 { 430 const char *p; 431 const char *r; 432 size_t count = 0; 433 434 for (p = s; *p != '\0'; ++p) { 435 for (r = reject; *r != '\0'; ++r) { 436 if (*p == *r) 437 return count; 438 } 439 ++count; 440 } 441 return count; 442 } 443 EXPORT_SYMBOL(strcspn); 444 #endif 445 446 #ifndef __HAVE_ARCH_STRPBRK 447 /** 448 * strpbrk - Find the first occurrence of a set of characters 449 * @cs: The string to be searched 450 * @ct: The characters to search for 451 */ 452 char *strpbrk(const char *cs, const char *ct) 453 { 454 const char *sc1, *sc2; 455 456 for (sc1 = cs; *sc1 != '\0'; ++sc1) { 457 for (sc2 = ct; *sc2 != '\0'; ++sc2) { 458 if (*sc1 == *sc2) 459 return (char *)sc1; 460 } 461 } 462 return NULL; 463 } 464 EXPORT_SYMBOL(strpbrk); 465 #endif 466 467 #ifndef __HAVE_ARCH_STRSEP 468 /** 469 * strsep - Split a string into tokens 470 * @s: The string to be searched 471 * @ct: The characters to search for 472 * 473 * strsep() updates @s to point after the token, ready for the next call. 474 * 475 * It returns empty tokens, too, behaving exactly like the libc function 476 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. 477 * Same semantics, slimmer shape. ;) 478 */ 479 char *strsep(char **s, const char *ct) 480 { 481 char *sbegin = *s; 482 char *end; 483 484 if (sbegin == NULL) 485 return NULL; 486 487 end = strpbrk(sbegin, ct); 488 if (end) 489 *end++ = '\0'; 490 *s = end; 491 return sbegin; 492 } 493 EXPORT_SYMBOL(strsep); 494 #endif 495 496 #ifndef __HAVE_ARCH_MEMSET 497 /** 498 * memset - Fill a region of memory with the given value 499 * @s: Pointer to the start of the area. 500 * @c: The byte to fill the area with 501 * @count: The size of the area. 502 * 503 * Do not use memset() to access IO space, use memset_io() instead. 504 */ 505 void *memset(void *s, int c, size_t count) 506 { 507 char *xs = s; 508 509 while (count--) 510 *xs++ = c; 511 return s; 512 } 513 EXPORT_SYMBOL(memset); 514 #endif 515 516 #ifndef __HAVE_ARCH_MEMCPY 517 /** 518 * memcpy - Copy one area of memory to another 519 * @dest: Where to copy to 520 * @src: Where to copy from 521 * @count: The size of the area. 522 * 523 * You should not use this function to access IO space, use memcpy_toio() 524 * or memcpy_fromio() instead. 525 */ 526 void *memcpy(void *dest, const void *src, size_t count) 527 { 528 char *tmp = dest; 529 const char *s = src; 530 531 while (count--) 532 *tmp++ = *s++; 533 return dest; 534 } 535 EXPORT_SYMBOL(memcpy); 536 #endif 537 538 #ifndef __HAVE_ARCH_MEMMOVE 539 /** 540 * memmove - Copy one area of memory to another 541 * @dest: Where to copy to 542 * @src: Where to copy from 543 * @count: The size of the area. 544 * 545 * Unlike memcpy(), memmove() copes with overlapping areas. 546 */ 547 void *memmove(void *dest, const void *src, size_t count) 548 { 549 char *tmp; 550 const char *s; 551 552 if (dest <= src) { 553 tmp = dest; 554 s = src; 555 while (count--) 556 *tmp++ = *s++; 557 } else { 558 tmp = dest; 559 tmp += count; 560 s = src; 561 s += count; 562 while (count--) 563 *--tmp = *--s; 564 } 565 return dest; 566 } 567 EXPORT_SYMBOL(memmove); 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 */ 577 #undef memcmp 578 int memcmp(const void *cs, const void *ct, size_t count) 579 { 580 const unsigned char *su1, *su2; 581 int res = 0; 582 583 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) 584 if ((res = *su1 - *su2) != 0) 585 break; 586 return res; 587 } 588 EXPORT_SYMBOL(memcmp); 589 #endif 590 591 #ifndef __HAVE_ARCH_MEMSCAN 592 /** 593 * memscan - Find a character in an area of memory. 594 * @addr: The memory area 595 * @c: The byte to search for 596 * @size: The size of the area. 597 * 598 * returns the address of the first occurrence of @c, or 1 byte past 599 * the area if @c is not found 600 */ 601 void *memscan(void *addr, int c, size_t size) 602 { 603 unsigned char *p = addr; 604 605 while (size) { 606 if (*p == c) 607 return (void *)p; 608 p++; 609 size--; 610 } 611 return (void *)p; 612 } 613 EXPORT_SYMBOL(memscan); 614 #endif 615 616 #ifndef __HAVE_ARCH_STRSTR 617 /** 618 * strstr - Find the first substring in a %NUL terminated string 619 * @s1: The string to be searched 620 * @s2: The string to search for 621 */ 622 char *strstr(const char *s1, const char *s2) 623 { 624 int l1, l2; 625 626 l2 = strlen(s2); 627 if (!l2) 628 return (char *)s1; 629 l1 = strlen(s1); 630 while (l1 >= l2) { 631 l1--; 632 if (!memcmp(s1, s2, l2)) 633 return (char *)s1; 634 s1++; 635 } 636 return NULL; 637 } 638 EXPORT_SYMBOL(strstr); 639 #endif 640 641 #ifndef __HAVE_ARCH_MEMCHR 642 /** 643 * memchr - Find a character in an area of memory. 644 * @s: The memory area 645 * @c: The byte to search for 646 * @n: The size of the area. 647 * 648 * returns the address of the first occurrence of @c, or %NULL 649 * if @c is not found 650 */ 651 void *memchr(const void *s, int c, size_t n) 652 { 653 const unsigned char *p = s; 654 while (n-- != 0) { 655 if ((unsigned char)c == *p++) { 656 return (void *)(p - 1); 657 } 658 } 659 return NULL; 660 } 661 EXPORT_SYMBOL(memchr); 662 #endif 663