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