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 #include <malloc.h> 22 23 24 /** 25 * strncasecmp - Case insensitive, length-limited string comparison 26 * @s1: One string 27 * @s2: The other string 28 * @len: the maximum number of characters to compare 29 */ 30 int strncasecmp(const char *s1, const char *s2, size_t len) 31 { 32 /* Yes, Virginia, it had better be unsigned */ 33 unsigned char c1, c2; 34 35 c1 = 0; c2 = 0; 36 if (len) { 37 do { 38 c1 = *s1; c2 = *s2; 39 s1++; s2++; 40 if (!c1) 41 break; 42 if (!c2) 43 break; 44 if (c1 == c2) 45 continue; 46 c1 = tolower(c1); 47 c2 = tolower(c2); 48 if (c1 != c2) 49 break; 50 } while (--len); 51 } 52 return (int)c1 - (int)c2; 53 } 54 55 /** 56 * strcasecmp - Case insensitive string comparison 57 * @s1: One string 58 * @s2: The other string 59 */ 60 int strcasecmp(const char *s1, const char *s2) 61 { 62 return strncasecmp(s1, s2, -1U); 63 } 64 65 char * ___strtok; 66 67 #ifndef __HAVE_ARCH_STRCPY 68 /** 69 * strcpy - Copy a %NUL terminated string 70 * @dest: Where to copy the string to 71 * @src: Where to copy the string from 72 */ 73 char * strcpy(char * dest,const char *src) 74 { 75 char *tmp = dest; 76 77 while ((*dest++ = *src++) != '\0') 78 /* nothing */; 79 return tmp; 80 } 81 #endif 82 83 #ifndef __HAVE_ARCH_STRNCPY 84 /** 85 * strncpy - Copy a length-limited, %NUL-terminated string 86 * @dest: Where to copy the string to 87 * @src: Where to copy the string from 88 * @count: The maximum number of bytes to copy 89 * 90 * Note that unlike userspace strncpy, this does not %NUL-pad the buffer. 91 * However, the result is not %NUL-terminated if the source exceeds 92 * @count bytes. 93 */ 94 char * strncpy(char * dest,const char *src,size_t count) 95 { 96 char *tmp = dest; 97 98 while (count-- && (*dest++ = *src++) != '\0') 99 /* nothing */; 100 101 return tmp; 102 } 103 #endif 104 105 #ifndef __HAVE_ARCH_STRLCPY 106 /** 107 * strlcpy - Copy a C-string into a sized buffer 108 * @dest: Where to copy the string to 109 * @src: Where to copy the string from 110 * @size: size of destination buffer 111 * 112 * Compatible with *BSD: the result is always a valid 113 * NUL-terminated string that fits in the buffer (unless, 114 * of course, the buffer size is zero). It does not pad 115 * out the result like strncpy() does. 116 */ 117 size_t strlcpy(char *dest, const char *src, size_t size) 118 { 119 size_t ret = strlen(src); 120 121 if (size) { 122 size_t len = (ret >= size) ? size - 1 : ret; 123 memcpy(dest, src, len); 124 dest[len] = '\0'; 125 } 126 return ret; 127 } 128 #endif 129 130 #ifndef __HAVE_ARCH_STRCAT 131 /** 132 * strcat - Append one %NUL-terminated string to another 133 * @dest: The string to be appended to 134 * @src: The string to append to it 135 */ 136 char * strcat(char * dest, const char * src) 137 { 138 char *tmp = dest; 139 140 while (*dest) 141 dest++; 142 while ((*dest++ = *src++) != '\0') 143 ; 144 145 return tmp; 146 } 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++)) { 167 if (--count == 0) { 168 *dest = '\0'; 169 break; 170 } 171 } 172 } 173 174 return tmp; 175 } 176 #endif 177 178 #ifndef __HAVE_ARCH_STRCMP 179 /** 180 * strcmp - Compare two strings 181 * @cs: One string 182 * @ct: Another string 183 */ 184 int strcmp(const char * cs,const char * ct) 185 { 186 register signed char __res; 187 188 while (1) { 189 if ((__res = *cs - *ct++) != 0 || !*cs++) 190 break; 191 } 192 193 return __res; 194 } 195 #endif 196 197 #ifndef __HAVE_ARCH_STRNCMP 198 /** 199 * strncmp - Compare two length-limited strings 200 * @cs: One string 201 * @ct: Another string 202 * @count: The maximum number of bytes to compare 203 */ 204 int strncmp(const char * cs,const char * ct,size_t count) 205 { 206 register signed char __res = 0; 207 208 while (count) { 209 if ((__res = *cs - *ct++) != 0 || !*cs++) 210 break; 211 count--; 212 } 213 214 return __res; 215 } 216 #endif 217 218 #ifndef __HAVE_ARCH_STRCHR 219 /** 220 * strchr - Find the first occurrence of a character in a string 221 * @s: The string to be searched 222 * @c: The character to search for 223 */ 224 char * strchr(const char * s, int c) 225 { 226 for(; *s != (char) c; ++s) 227 if (*s == '\0') 228 return NULL; 229 return (char *) s; 230 } 231 #endif 232 233 const char *strchrnul(const char *s, int c) 234 { 235 for (; *s != (char)c; ++s) 236 if (*s == '\0') 237 break; 238 return s; 239 } 240 241 #ifndef __HAVE_ARCH_STRRCHR 242 /** 243 * strrchr - Find the last occurrence of a character in a string 244 * @s: The string to be searched 245 * @c: The character to search for 246 */ 247 char * strrchr(const char * s, int c) 248 { 249 const char *p = s + strlen(s); 250 do { 251 if (*p == (char)c) 252 return (char *)p; 253 } while (--p >= s); 254 return NULL; 255 } 256 #endif 257 258 #ifndef __HAVE_ARCH_STRLEN 259 /** 260 * strlen - Find the length of a string 261 * @s: The string to be sized 262 */ 263 size_t strlen(const char * s) 264 { 265 const char *sc; 266 267 for (sc = s; *sc != '\0'; ++sc) 268 /* nothing */; 269 return sc - s; 270 } 271 #endif 272 273 #ifndef __HAVE_ARCH_STRNLEN 274 /** 275 * strnlen - Find the length of a length-limited string 276 * @s: The string to be sized 277 * @count: The maximum number of bytes to search 278 */ 279 size_t strnlen(const char * s, size_t count) 280 { 281 const char *sc; 282 283 for (sc = s; count-- && *sc != '\0'; ++sc) 284 /* nothing */; 285 return sc - s; 286 } 287 #endif 288 289 #ifndef __HAVE_ARCH_STRCSPN 290 /** 291 * strcspn - Calculate the length of the initial substring of @s which does 292 * not contain letters in @reject 293 * @s: The string to be searched 294 * @reject: The string to avoid 295 */ 296 size_t strcspn(const char *s, const char *reject) 297 { 298 const char *p; 299 const char *r; 300 size_t count = 0; 301 302 for (p = s; *p != '\0'; ++p) { 303 for (r = reject; *r != '\0'; ++r) { 304 if (*p == *r) 305 return count; 306 } 307 ++count; 308 } 309 return count; 310 } 311 #endif 312 313 #ifndef __HAVE_ARCH_STRDUP 314 char * strdup(const char *s) 315 { 316 char *new; 317 318 if ((s == NULL) || 319 ((new = malloc (strlen(s) + 1)) == NULL) ) { 320 return NULL; 321 } 322 323 strcpy (new, s); 324 return new; 325 } 326 #endif 327 328 #ifndef __HAVE_ARCH_STRSPN 329 /** 330 * strspn - Calculate the length of the initial substring of @s which only 331 * contain letters in @accept 332 * @s: The string to be searched 333 * @accept: The string to search for 334 */ 335 size_t strspn(const char *s, const char *accept) 336 { 337 const char *p; 338 const char *a; 339 size_t count = 0; 340 341 for (p = s; *p != '\0'; ++p) { 342 for (a = accept; *a != '\0'; ++a) { 343 if (*p == *a) 344 break; 345 } 346 if (*a == '\0') 347 return count; 348 ++count; 349 } 350 351 return count; 352 } 353 #endif 354 355 #ifndef __HAVE_ARCH_STRPBRK 356 /** 357 * strpbrk - Find the first occurrence of a set of characters 358 * @cs: The string to be searched 359 * @ct: The characters to search for 360 */ 361 char * strpbrk(const char * cs,const char * ct) 362 { 363 const char *sc1,*sc2; 364 365 for( sc1 = cs; *sc1 != '\0'; ++sc1) { 366 for( sc2 = ct; *sc2 != '\0'; ++sc2) { 367 if (*sc1 == *sc2) 368 return (char *) sc1; 369 } 370 } 371 return NULL; 372 } 373 #endif 374 375 #ifndef __HAVE_ARCH_STRTOK 376 /** 377 * strtok - Split a string into tokens 378 * @s: The string to be searched 379 * @ct: The characters to search for 380 * 381 * WARNING: strtok is deprecated, use strsep instead. 382 */ 383 char * strtok(char * s,const char * ct) 384 { 385 char *sbegin, *send; 386 387 sbegin = s ? s : ___strtok; 388 if (!sbegin) { 389 return NULL; 390 } 391 sbegin += strspn(sbegin,ct); 392 if (*sbegin == '\0') { 393 ___strtok = NULL; 394 return( NULL ); 395 } 396 send = strpbrk( sbegin, ct); 397 if (send && *send != '\0') 398 *send++ = '\0'; 399 ___strtok = send; 400 return (sbegin); 401 } 402 #endif 403 404 #ifndef __HAVE_ARCH_STRSEP 405 /** 406 * strsep - Split a string into tokens 407 * @s: The string to be searched 408 * @ct: The characters to search for 409 * 410 * strsep() updates @s to point after the token, ready for the next call. 411 * 412 * It returns empty tokens, too, behaving exactly like the libc function 413 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. 414 * Same semantics, slimmer shape. ;) 415 */ 416 char * strsep(char **s, const char *ct) 417 { 418 char *sbegin = *s, *end; 419 420 if (sbegin == NULL) 421 return NULL; 422 423 end = strpbrk(sbegin, ct); 424 if (end) 425 *end++ = '\0'; 426 *s = end; 427 428 return sbegin; 429 } 430 #endif 431 432 #ifndef __HAVE_ARCH_STRSWAB 433 /** 434 * strswab - swap adjacent even and odd bytes in %NUL-terminated string 435 * s: address of the string 436 * 437 * returns the address of the swapped string or NULL on error. If 438 * string length is odd, last byte is untouched. 439 */ 440 char *strswab(const char *s) 441 { 442 char *p, *q; 443 444 if ((NULL == s) || ('\0' == *s)) { 445 return (NULL); 446 } 447 448 for (p=(char *)s, q=p+1; (*p != '\0') && (*q != '\0'); p+=2, q+=2) { 449 char tmp; 450 451 tmp = *p; 452 *p = *q; 453 *q = tmp; 454 } 455 456 return (char *) s; 457 } 458 #endif 459 460 #ifndef __HAVE_ARCH_MEMSET 461 /** 462 * memset - Fill a region of memory with the given value 463 * @s: Pointer to the start of the area. 464 * @c: The byte to fill the area with 465 * @count: The size of the area. 466 * 467 * Do not use memset() to access IO space, use memset_io() instead. 468 */ 469 void * memset(void * s,int c,size_t count) 470 { 471 unsigned long *sl = (unsigned long *) s; 472 char *s8; 473 474 #if !CONFIG_IS_ENABLED(TINY_MEMSET) 475 unsigned long cl = 0; 476 int i; 477 478 /* do it one word at a time (32 bits or 64 bits) while possible */ 479 if ( ((ulong)s & (sizeof(*sl) - 1)) == 0) { 480 for (i = 0; i < sizeof(*sl); i++) { 481 cl <<= 8; 482 cl |= c & 0xff; 483 } 484 while (count >= sizeof(*sl)) { 485 *sl++ = cl; 486 count -= sizeof(*sl); 487 } 488 } 489 #endif /* fill 8 bits at a time */ 490 s8 = (char *)sl; 491 while (count--) 492 *s8++ = c; 493 494 return s; 495 } 496 #endif 497 498 #ifndef __HAVE_ARCH_MEMCPY 499 /** 500 * memcpy - Copy one area of memory to another 501 * @dest: Where to copy to 502 * @src: Where to copy from 503 * @count: The size of the area. 504 * 505 * You should not use this function to access IO space, use memcpy_toio() 506 * or memcpy_fromio() instead. 507 */ 508 void * memcpy(void *dest, const void *src, size_t count) 509 { 510 unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src; 511 char *d8, *s8; 512 513 if (src == dest) 514 return dest; 515 516 /* while all data is aligned (common case), copy a word at a time */ 517 if ( (((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) { 518 while (count >= sizeof(*dl)) { 519 *dl++ = *sl++; 520 count -= sizeof(*dl); 521 } 522 } 523 /* copy the reset one byte at a time */ 524 d8 = (char *)dl; 525 s8 = (char *)sl; 526 while (count--) 527 *d8++ = *s8++; 528 529 return dest; 530 } 531 #endif 532 533 #ifndef __HAVE_ARCH_MEMMOVE 534 /** 535 * memmove - Copy one area of memory to another 536 * @dest: Where to copy to 537 * @src: Where to copy from 538 * @count: The size of the area. 539 * 540 * Unlike memcpy(), memmove() copes with overlapping areas. 541 */ 542 void * memmove(void * dest,const void *src,size_t count) 543 { 544 char *tmp, *s; 545 546 if (dest <= src) { 547 memcpy(dest, src, count); 548 } else { 549 tmp = (char *) dest + count; 550 s = (char *) src + count; 551 while (count--) 552 *--tmp = *--s; 553 } 554 555 return dest; 556 } 557 #endif 558 559 #ifndef __HAVE_ARCH_MEMCMP 560 /** 561 * memcmp - Compare two areas of memory 562 * @cs: One area of memory 563 * @ct: Another area of memory 564 * @count: The size of the area. 565 */ 566 int memcmp(const void * cs,const void * ct,size_t count) 567 { 568 const unsigned char *su1, *su2; 569 int res = 0; 570 571 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) 572 if ((res = *su1 - *su2) != 0) 573 break; 574 return res; 575 } 576 #endif 577 578 #ifndef __HAVE_ARCH_MEMSCAN 579 /** 580 * memscan - Find a character in an area of memory. 581 * @addr: The memory area 582 * @c: The byte to search for 583 * @size: The size of the area. 584 * 585 * returns the address of the first occurrence of @c, or 1 byte past 586 * the area if @c is not found 587 */ 588 void * memscan(void * addr, int c, size_t size) 589 { 590 unsigned char * p = (unsigned char *) addr; 591 592 while (size) { 593 if (*p == c) 594 return (void *) p; 595 p++; 596 size--; 597 } 598 return (void *) p; 599 } 600 #endif 601 602 #ifndef __HAVE_ARCH_STRSTR 603 /** 604 * strstr - Find the first substring in a %NUL terminated string 605 * @s1: The string to be searched 606 * @s2: The string to search for 607 */ 608 char * strstr(const char * s1,const char * s2) 609 { 610 int l1, l2; 611 612 l2 = strlen(s2); 613 if (!l2) 614 return (char *) s1; 615 l1 = strlen(s1); 616 while (l1 >= l2) { 617 l1--; 618 if (!memcmp(s1,s2,l2)) 619 return (char *) s1; 620 s1++; 621 } 622 return NULL; 623 } 624 #endif 625 626 #ifndef __HAVE_ARCH_MEMCHR 627 /** 628 * memchr - Find a character in an area of memory. 629 * @s: The memory area 630 * @c: The byte to search for 631 * @n: The size of the area. 632 * 633 * returns the address of the first occurrence of @c, or %NULL 634 * if @c is not found 635 */ 636 void *memchr(const void *s, int c, size_t n) 637 { 638 const unsigned char *p = s; 639 while (n-- != 0) { 640 if ((unsigned char)c == *p++) { 641 return (void *)(p-1); 642 } 643 } 644 return NULL; 645 } 646 647 #endif 648 #ifndef __HAVE_ARCH_MEMCHR_INV 649 static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) 650 { 651 while (bytes) { 652 if (*start != value) 653 return (void *)start; 654 start++; 655 bytes--; 656 } 657 return NULL; 658 } 659 /** 660 * memchr_inv - Find an unmatching character in an area of memory. 661 * @start: The memory area 662 * @c: Find a character other than c 663 * @bytes: The size of the area. 664 * 665 * returns the address of the first character other than @c, or %NULL 666 * if the whole buffer contains just @c. 667 */ 668 void *memchr_inv(const void *start, int c, size_t bytes) 669 { 670 u8 value = c; 671 u64 value64; 672 unsigned int words, prefix; 673 674 if (bytes <= 16) 675 return check_bytes8(start, value, bytes); 676 677 value64 = value; 678 value64 |= value64 << 8; 679 value64 |= value64 << 16; 680 value64 |= value64 << 32; 681 682 prefix = (unsigned long)start % 8; 683 if (prefix) { 684 u8 *r; 685 686 prefix = 8 - prefix; 687 r = check_bytes8(start, value, prefix); 688 if (r) 689 return r; 690 start += prefix; 691 bytes -= prefix; 692 } 693 694 words = bytes / 8; 695 696 while (words) { 697 if (*(u64 *)start != value64) 698 return check_bytes8(start, value, 8); 699 start += 8; 700 words--; 701 } 702 703 return check_bytes8(start, value, bytes % 8); 704 } 705 #endif 706