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 unsigned char c1, c2; 250 251 while (1) { 252 c1 = *cs++; 253 c2 = *ct++; 254 if (c1 != c2) 255 return c1 < c2 ? -1 : 1; 256 if (!c1) 257 break; 258 } 259 return 0; 260 } 261 EXPORT_SYMBOL(strcmp); 262 #endif 263 264 #ifndef __HAVE_ARCH_STRNCMP 265 /** 266 * strncmp - Compare two length-limited strings 267 * @cs: One string 268 * @ct: Another string 269 * @count: The maximum number of bytes to compare 270 */ 271 int strncmp(const char *cs, const char *ct, size_t count) 272 { 273 unsigned char c1, c2; 274 275 while (count) { 276 c1 = *cs++; 277 c2 = *ct++; 278 if (c1 != c2) 279 return c1 < c2 ? -1 : 1; 280 if (!c1) 281 break; 282 count--; 283 } 284 return 0; 285 } 286 EXPORT_SYMBOL(strncmp); 287 #endif 288 289 #ifndef __HAVE_ARCH_STRCHR 290 /** 291 * strchr - Find the first occurrence of a character in a string 292 * @s: The string to be searched 293 * @c: The character to search for 294 */ 295 char *strchr(const char *s, int c) 296 { 297 for (; *s != (char)c; ++s) 298 if (*s == '\0') 299 return NULL; 300 return (char *)s; 301 } 302 EXPORT_SYMBOL(strchr); 303 #endif 304 305 #ifndef __HAVE_ARCH_STRRCHR 306 /** 307 * strrchr - Find the last occurrence of a character in a string 308 * @s: The string to be searched 309 * @c: The character to search for 310 */ 311 char *strrchr(const char *s, int c) 312 { 313 const char *p = s + strlen(s); 314 do { 315 if (*p == (char)c) 316 return (char *)p; 317 } while (--p >= s); 318 return NULL; 319 } 320 EXPORT_SYMBOL(strrchr); 321 #endif 322 323 #ifndef __HAVE_ARCH_STRNCHR 324 /** 325 * strnchr - Find a character in a length limited string 326 * @s: The string to be searched 327 * @count: The number of characters to be searched 328 * @c: The character to search for 329 */ 330 char *strnchr(const char *s, size_t count, int c) 331 { 332 for (; count-- && *s != '\0'; ++s) 333 if (*s == (char)c) 334 return (char *)s; 335 return NULL; 336 } 337 EXPORT_SYMBOL(strnchr); 338 #endif 339 340 /** 341 * skip_spaces - Removes leading whitespace from @str. 342 * @str: The string to be stripped. 343 * 344 * Returns a pointer to the first non-whitespace character in @str. 345 */ 346 char *skip_spaces(const char *str) 347 { 348 while (isspace(*str)) 349 ++str; 350 return (char *)str; 351 } 352 EXPORT_SYMBOL(skip_spaces); 353 354 /** 355 * strim - Removes leading and trailing whitespace from @s. 356 * @s: The string to be stripped. 357 * 358 * Note that the first trailing whitespace is replaced with a %NUL-terminator 359 * in the given string @s. Returns a pointer to the first non-whitespace 360 * character in @s. 361 */ 362 char *strim(char *s) 363 { 364 size_t size; 365 char *end; 366 367 s = skip_spaces(s); 368 size = strlen(s); 369 if (!size) 370 return s; 371 372 end = s + size - 1; 373 while (end >= s && isspace(*end)) 374 end--; 375 *(end + 1) = '\0'; 376 377 return s; 378 } 379 EXPORT_SYMBOL(strim); 380 381 #ifndef __HAVE_ARCH_STRLEN 382 /** 383 * strlen - Find the length of a string 384 * @s: The string to be sized 385 */ 386 size_t strlen(const char *s) 387 { 388 const char *sc; 389 390 for (sc = s; *sc != '\0'; ++sc) 391 /* nothing */; 392 return sc - s; 393 } 394 EXPORT_SYMBOL(strlen); 395 #endif 396 397 #ifndef __HAVE_ARCH_STRNLEN 398 /** 399 * strnlen - Find the length of a length-limited string 400 * @s: The string to be sized 401 * @count: The maximum number of bytes to search 402 */ 403 size_t strnlen(const char *s, size_t count) 404 { 405 const char *sc; 406 407 for (sc = s; count-- && *sc != '\0'; ++sc) 408 /* nothing */; 409 return sc - s; 410 } 411 EXPORT_SYMBOL(strnlen); 412 #endif 413 414 #ifndef __HAVE_ARCH_STRSPN 415 /** 416 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept 417 * @s: The string to be searched 418 * @accept: The string to search for 419 */ 420 size_t strspn(const char *s, const char *accept) 421 { 422 const char *p; 423 const char *a; 424 size_t count = 0; 425 426 for (p = s; *p != '\0'; ++p) { 427 for (a = accept; *a != '\0'; ++a) { 428 if (*p == *a) 429 break; 430 } 431 if (*a == '\0') 432 return count; 433 ++count; 434 } 435 return count; 436 } 437 438 EXPORT_SYMBOL(strspn); 439 #endif 440 441 #ifndef __HAVE_ARCH_STRCSPN 442 /** 443 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject 444 * @s: The string to be searched 445 * @reject: The string to avoid 446 */ 447 size_t strcspn(const char *s, const char *reject) 448 { 449 const char *p; 450 const char *r; 451 size_t count = 0; 452 453 for (p = s; *p != '\0'; ++p) { 454 for (r = reject; *r != '\0'; ++r) { 455 if (*p == *r) 456 return count; 457 } 458 ++count; 459 } 460 return count; 461 } 462 EXPORT_SYMBOL(strcspn); 463 #endif 464 465 #ifndef __HAVE_ARCH_STRPBRK 466 /** 467 * strpbrk - Find the first occurrence of a set of characters 468 * @cs: The string to be searched 469 * @ct: The characters to search for 470 */ 471 char *strpbrk(const char *cs, const char *ct) 472 { 473 const char *sc1, *sc2; 474 475 for (sc1 = cs; *sc1 != '\0'; ++sc1) { 476 for (sc2 = ct; *sc2 != '\0'; ++sc2) { 477 if (*sc1 == *sc2) 478 return (char *)sc1; 479 } 480 } 481 return NULL; 482 } 483 EXPORT_SYMBOL(strpbrk); 484 #endif 485 486 #ifndef __HAVE_ARCH_STRSEP 487 /** 488 * strsep - Split a string into tokens 489 * @s: The string to be searched 490 * @ct: The characters to search for 491 * 492 * strsep() updates @s to point after the token, ready for the next call. 493 * 494 * It returns empty tokens, too, behaving exactly like the libc function 495 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. 496 * Same semantics, slimmer shape. ;) 497 */ 498 char *strsep(char **s, const char *ct) 499 { 500 char *sbegin = *s; 501 char *end; 502 503 if (sbegin == NULL) 504 return NULL; 505 506 end = strpbrk(sbegin, ct); 507 if (end) 508 *end++ = '\0'; 509 *s = end; 510 return sbegin; 511 } 512 EXPORT_SYMBOL(strsep); 513 #endif 514 515 /** 516 * sysfs_streq - return true if strings are equal, modulo trailing newline 517 * @s1: one string 518 * @s2: another string 519 * 520 * This routine returns true iff two strings are equal, treating both 521 * NUL and newline-then-NUL as equivalent string terminations. It's 522 * geared for use with sysfs input strings, which generally terminate 523 * with newlines but are compared against values without newlines. 524 */ 525 bool sysfs_streq(const char *s1, const char *s2) 526 { 527 while (*s1 && *s1 == *s2) { 528 s1++; 529 s2++; 530 } 531 532 if (*s1 == *s2) 533 return true; 534 if (!*s1 && *s2 == '\n' && !s2[1]) 535 return true; 536 if (*s1 == '\n' && !s1[1] && !*s2) 537 return true; 538 return false; 539 } 540 EXPORT_SYMBOL(sysfs_streq); 541 542 #ifndef __HAVE_ARCH_MEMSET 543 /** 544 * memset - Fill a region of memory with the given value 545 * @s: Pointer to the start of the area. 546 * @c: The byte to fill the area with 547 * @count: The size of the area. 548 * 549 * Do not use memset() to access IO space, use memset_io() instead. 550 */ 551 void *memset(void *s, int c, size_t count) 552 { 553 char *xs = s; 554 555 while (count--) 556 *xs++ = c; 557 return s; 558 } 559 EXPORT_SYMBOL(memset); 560 #endif 561 562 #ifndef __HAVE_ARCH_MEMCPY 563 /** 564 * memcpy - Copy one area of memory to another 565 * @dest: Where to copy to 566 * @src: Where to copy from 567 * @count: The size of the area. 568 * 569 * You should not use this function to access IO space, use memcpy_toio() 570 * or memcpy_fromio() instead. 571 */ 572 void *memcpy(void *dest, const void *src, size_t count) 573 { 574 char *tmp = dest; 575 const char *s = src; 576 577 while (count--) 578 *tmp++ = *s++; 579 return dest; 580 } 581 EXPORT_SYMBOL(memcpy); 582 #endif 583 584 #ifndef __HAVE_ARCH_MEMMOVE 585 /** 586 * memmove - Copy one area of memory to another 587 * @dest: Where to copy to 588 * @src: Where to copy from 589 * @count: The size of the area. 590 * 591 * Unlike memcpy(), memmove() copes with overlapping areas. 592 */ 593 void *memmove(void *dest, const void *src, size_t count) 594 { 595 char *tmp; 596 const char *s; 597 598 if (dest <= src) { 599 tmp = dest; 600 s = src; 601 while (count--) 602 *tmp++ = *s++; 603 } else { 604 tmp = dest; 605 tmp += count; 606 s = src; 607 s += count; 608 while (count--) 609 *--tmp = *--s; 610 } 611 return dest; 612 } 613 EXPORT_SYMBOL(memmove); 614 #endif 615 616 #ifndef __HAVE_ARCH_MEMCMP 617 /** 618 * memcmp - Compare two areas of memory 619 * @cs: One area of memory 620 * @ct: Another area of memory 621 * @count: The size of the area. 622 */ 623 #undef memcmp 624 int memcmp(const void *cs, const void *ct, size_t count) 625 { 626 const unsigned char *su1, *su2; 627 int res = 0; 628 629 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) 630 if ((res = *su1 - *su2) != 0) 631 break; 632 return res; 633 } 634 EXPORT_SYMBOL(memcmp); 635 #endif 636 637 #ifndef __HAVE_ARCH_MEMSCAN 638 /** 639 * memscan - Find a character in an area of memory. 640 * @addr: The memory area 641 * @c: The byte to search for 642 * @size: The size of the area. 643 * 644 * returns the address of the first occurrence of @c, or 1 byte past 645 * the area if @c is not found 646 */ 647 void *memscan(void *addr, int c, size_t size) 648 { 649 unsigned char *p = addr; 650 651 while (size) { 652 if (*p == c) 653 return (void *)p; 654 p++; 655 size--; 656 } 657 return (void *)p; 658 } 659 EXPORT_SYMBOL(memscan); 660 #endif 661 662 #ifndef __HAVE_ARCH_STRSTR 663 /** 664 * strstr - Find the first substring in a %NUL terminated string 665 * @s1: The string to be searched 666 * @s2: The string to search for 667 */ 668 char *strstr(const char *s1, const char *s2) 669 { 670 int l1, l2; 671 672 l2 = strlen(s2); 673 if (!l2) 674 return (char *)s1; 675 l1 = strlen(s1); 676 while (l1 >= l2) { 677 l1--; 678 if (!memcmp(s1, s2, l2)) 679 return (char *)s1; 680 s1++; 681 } 682 return NULL; 683 } 684 EXPORT_SYMBOL(strstr); 685 #endif 686 687 #ifndef __HAVE_ARCH_MEMCHR 688 /** 689 * memchr - Find a character in an area of memory. 690 * @s: The memory area 691 * @c: The byte to search for 692 * @n: The size of the area. 693 * 694 * returns the address of the first occurrence of @c, or %NULL 695 * if @c is not found 696 */ 697 void *memchr(const void *s, int c, size_t n) 698 { 699 const unsigned char *p = s; 700 while (n-- != 0) { 701 if ((unsigned char)c == *p++) { 702 return (void *)(p - 1); 703 } 704 } 705 return NULL; 706 } 707 EXPORT_SYMBOL(memchr); 708 #endif 709