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_STRCAT 106 /** 107 * strcat - Append one %NUL-terminated string to another 108 * @dest: The string to be appended to 109 * @src: The string to append to it 110 */ 111 char * strcat(char * dest, const char * src) 112 { 113 char *tmp = dest; 114 115 while (*dest) 116 dest++; 117 while ((*dest++ = *src++) != '\0') 118 ; 119 120 return tmp; 121 } 122 #endif 123 124 #ifndef __HAVE_ARCH_STRNCAT 125 /** 126 * strncat - Append a length-limited, %NUL-terminated string to another 127 * @dest: The string to be appended to 128 * @src: The string to append to it 129 * @count: The maximum numbers of bytes to copy 130 * 131 * Note that in contrast to strncpy, strncat ensures the result is 132 * terminated. 133 */ 134 char * strncat(char *dest, const char *src, size_t count) 135 { 136 char *tmp = dest; 137 138 if (count) { 139 while (*dest) 140 dest++; 141 while ((*dest++ = *src++)) { 142 if (--count == 0) { 143 *dest = '\0'; 144 break; 145 } 146 } 147 } 148 149 return tmp; 150 } 151 #endif 152 153 #ifndef __HAVE_ARCH_STRCMP 154 /** 155 * strcmp - Compare two strings 156 * @cs: One string 157 * @ct: Another string 158 */ 159 int strcmp(const char * cs,const char * ct) 160 { 161 register signed char __res; 162 163 while (1) { 164 if ((__res = *cs - *ct++) != 0 || !*cs++) 165 break; 166 } 167 168 return __res; 169 } 170 #endif 171 172 #ifndef __HAVE_ARCH_STRNCMP 173 /** 174 * strncmp - Compare two length-limited strings 175 * @cs: One string 176 * @ct: Another string 177 * @count: The maximum number of bytes to compare 178 */ 179 int strncmp(const char * cs,const char * ct,size_t count) 180 { 181 register signed char __res = 0; 182 183 while (count) { 184 if ((__res = *cs - *ct++) != 0 || !*cs++) 185 break; 186 count--; 187 } 188 189 return __res; 190 } 191 #endif 192 193 #ifndef __HAVE_ARCH_STRCHR 194 /** 195 * strchr - Find the first occurrence of a character in a string 196 * @s: The string to be searched 197 * @c: The character to search for 198 */ 199 char * strchr(const char * s, int c) 200 { 201 for(; *s != (char) c; ++s) 202 if (*s == '\0') 203 return NULL; 204 return (char *) s; 205 } 206 #endif 207 208 #ifndef __HAVE_ARCH_STRRCHR 209 /** 210 * strrchr - Find the last occurrence of a character in a string 211 * @s: The string to be searched 212 * @c: The character to search for 213 */ 214 char * strrchr(const char * s, int c) 215 { 216 const char *p = s + strlen(s); 217 do { 218 if (*p == (char)c) 219 return (char *)p; 220 } while (--p >= s); 221 return NULL; 222 } 223 #endif 224 225 #ifndef __HAVE_ARCH_STRLEN 226 /** 227 * strlen - Find the length of a string 228 * @s: The string to be sized 229 */ 230 size_t strlen(const char * s) 231 { 232 const char *sc; 233 234 for (sc = s; *sc != '\0'; ++sc) 235 /* nothing */; 236 return sc - s; 237 } 238 #endif 239 240 #ifndef __HAVE_ARCH_STRNLEN 241 /** 242 * strnlen - Find the length of a length-limited string 243 * @s: The string to be sized 244 * @count: The maximum number of bytes to search 245 */ 246 size_t strnlen(const char * s, size_t count) 247 { 248 const char *sc; 249 250 for (sc = s; count-- && *sc != '\0'; ++sc) 251 /* nothing */; 252 return sc - s; 253 } 254 #endif 255 256 #ifndef __HAVE_ARCH_STRDUP 257 char * strdup(const char *s) 258 { 259 char *new; 260 261 if ((s == NULL) || 262 ((new = malloc (strlen(s) + 1)) == NULL) ) { 263 return NULL; 264 } 265 266 strcpy (new, s); 267 return new; 268 } 269 #endif 270 271 #ifndef __HAVE_ARCH_STRSPN 272 /** 273 * strspn - Calculate the length of the initial substring of @s which only 274 * contain letters in @accept 275 * @s: The string to be searched 276 * @accept: The string to search for 277 */ 278 size_t strspn(const char *s, const char *accept) 279 { 280 const char *p; 281 const char *a; 282 size_t count = 0; 283 284 for (p = s; *p != '\0'; ++p) { 285 for (a = accept; *a != '\0'; ++a) { 286 if (*p == *a) 287 break; 288 } 289 if (*a == '\0') 290 return count; 291 ++count; 292 } 293 294 return count; 295 } 296 #endif 297 298 #ifndef __HAVE_ARCH_STRPBRK 299 /** 300 * strpbrk - Find the first occurrence of a set of characters 301 * @cs: The string to be searched 302 * @ct: The characters to search for 303 */ 304 char * strpbrk(const char * cs,const char * ct) 305 { 306 const char *sc1,*sc2; 307 308 for( sc1 = cs; *sc1 != '\0'; ++sc1) { 309 for( sc2 = ct; *sc2 != '\0'; ++sc2) { 310 if (*sc1 == *sc2) 311 return (char *) sc1; 312 } 313 } 314 return NULL; 315 } 316 #endif 317 318 #ifndef __HAVE_ARCH_STRTOK 319 /** 320 * strtok - Split a string into tokens 321 * @s: The string to be searched 322 * @ct: The characters to search for 323 * 324 * WARNING: strtok is deprecated, use strsep instead. 325 */ 326 char * strtok(char * s,const char * ct) 327 { 328 char *sbegin, *send; 329 330 sbegin = s ? s : ___strtok; 331 if (!sbegin) { 332 return NULL; 333 } 334 sbegin += strspn(sbegin,ct); 335 if (*sbegin == '\0') { 336 ___strtok = NULL; 337 return( NULL ); 338 } 339 send = strpbrk( sbegin, ct); 340 if (send && *send != '\0') 341 *send++ = '\0'; 342 ___strtok = send; 343 return (sbegin); 344 } 345 #endif 346 347 #ifndef __HAVE_ARCH_STRSEP 348 /** 349 * strsep - Split a string into tokens 350 * @s: The string to be searched 351 * @ct: The characters to search for 352 * 353 * strsep() updates @s to point after the token, ready for the next call. 354 * 355 * It returns empty tokens, too, behaving exactly like the libc function 356 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. 357 * Same semantics, slimmer shape. ;) 358 */ 359 char * strsep(char **s, const char *ct) 360 { 361 char *sbegin = *s, *end; 362 363 if (sbegin == NULL) 364 return NULL; 365 366 end = strpbrk(sbegin, ct); 367 if (end) 368 *end++ = '\0'; 369 *s = end; 370 371 return sbegin; 372 } 373 #endif 374 375 #ifndef __HAVE_ARCH_STRSWAB 376 /** 377 * strswab - swap adjacent even and odd bytes in %NUL-terminated string 378 * s: address of the string 379 * 380 * returns the address of the swapped string or NULL on error. If 381 * string length is odd, last byte is untouched. 382 */ 383 char *strswab(const char *s) 384 { 385 char *p, *q; 386 387 if ((NULL == s) || ('\0' == *s)) { 388 return (NULL); 389 } 390 391 for (p=(char *)s, q=p+1; (*p != '\0') && (*q != '\0'); p+=2, q+=2) { 392 char tmp; 393 394 tmp = *p; 395 *p = *q; 396 *q = tmp; 397 } 398 399 return (char *) s; 400 } 401 #endif 402 403 #ifndef __HAVE_ARCH_MEMSET 404 /** 405 * memset - Fill a region of memory with the given value 406 * @s: Pointer to the start of the area. 407 * @c: The byte to fill the area with 408 * @count: The size of the area. 409 * 410 * Do not use memset() to access IO space, use memset_io() instead. 411 */ 412 void * memset(void * s,int c,size_t count) 413 { 414 unsigned long *sl = (unsigned long *) s; 415 unsigned long cl = 0; 416 char *s8; 417 int i; 418 419 /* do it one word at a time (32 bits or 64 bits) while possible */ 420 if ( ((ulong)s & (sizeof(*sl) - 1)) == 0) { 421 for (i = 0; i < sizeof(*sl); i++) { 422 cl <<= 8; 423 cl |= c & 0xff; 424 } 425 while (count >= sizeof(*sl)) { 426 *sl++ = cl; 427 count -= sizeof(*sl); 428 } 429 } 430 /* fill 8 bits at a time */ 431 s8 = (char *)sl; 432 while (count--) 433 *s8++ = c; 434 435 return s; 436 } 437 #endif 438 439 #ifndef __HAVE_ARCH_BCOPY 440 /** 441 * bcopy - Copy one area of memory to another 442 * @src: Where to copy from 443 * @dest: Where to copy to 444 * @count: The size of the area. 445 * 446 * Note that this is the same as memcpy(), with the arguments reversed. 447 * memcpy() is the standard, bcopy() is a legacy BSD function. 448 * 449 * You should not use this function to access IO space, use memcpy_toio() 450 * or memcpy_fromio() instead. 451 */ 452 char * bcopy(const char * src, char * dest, int count) 453 { 454 char *tmp = dest; 455 456 while (count--) 457 *tmp++ = *src++; 458 459 return dest; 460 } 461 #endif 462 463 #ifndef __HAVE_ARCH_MEMCPY 464 /** 465 * memcpy - Copy one area of memory to another 466 * @dest: Where to copy to 467 * @src: Where to copy from 468 * @count: The size of the area. 469 * 470 * You should not use this function to access IO space, use memcpy_toio() 471 * or memcpy_fromio() instead. 472 */ 473 void * memcpy(void *dest, const void *src, size_t count) 474 { 475 unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src; 476 char *d8, *s8; 477 478 if (src == dest) 479 return dest; 480 481 /* while all data is aligned (common case), copy a word at a time */ 482 if ( (((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) { 483 while (count >= sizeof(*dl)) { 484 *dl++ = *sl++; 485 count -= sizeof(*dl); 486 } 487 } 488 /* copy the reset one byte at a time */ 489 d8 = (char *)dl; 490 s8 = (char *)sl; 491 while (count--) 492 *d8++ = *s8++; 493 494 return dest; 495 } 496 #endif 497 498 #ifndef __HAVE_ARCH_MEMMOVE 499 /** 500 * memmove - 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 * Unlike memcpy(), memmove() copes with overlapping areas. 506 */ 507 void * memmove(void * dest,const void *src,size_t count) 508 { 509 char *tmp, *s; 510 511 if (src == dest) 512 return dest; 513 514 if (dest <= src) { 515 tmp = (char *) dest; 516 s = (char *) src; 517 while (count--) 518 *tmp++ = *s++; 519 } 520 else { 521 tmp = (char *) dest + count; 522 s = (char *) src + count; 523 while (count--) 524 *--tmp = *--s; 525 } 526 527 return dest; 528 } 529 #endif 530 531 #ifndef __HAVE_ARCH_MEMCMP 532 /** 533 * memcmp - Compare two areas of memory 534 * @cs: One area of memory 535 * @ct: Another area of memory 536 * @count: The size of the area. 537 */ 538 int memcmp(const void * cs,const void * ct,size_t count) 539 { 540 const unsigned char *su1, *su2; 541 int res = 0; 542 543 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) 544 if ((res = *su1 - *su2) != 0) 545 break; 546 return res; 547 } 548 #endif 549 550 #ifndef __HAVE_ARCH_MEMSCAN 551 /** 552 * memscan - Find a character in an area of memory. 553 * @addr: The memory area 554 * @c: The byte to search for 555 * @size: The size of the area. 556 * 557 * returns the address of the first occurrence of @c, or 1 byte past 558 * the area if @c is not found 559 */ 560 void * memscan(void * addr, int c, size_t size) 561 { 562 unsigned char * p = (unsigned char *) addr; 563 564 while (size) { 565 if (*p == c) 566 return (void *) p; 567 p++; 568 size--; 569 } 570 return (void *) p; 571 } 572 #endif 573 574 #ifndef __HAVE_ARCH_STRSTR 575 /** 576 * strstr - Find the first substring in a %NUL terminated string 577 * @s1: The string to be searched 578 * @s2: The string to search for 579 */ 580 char * strstr(const char * s1,const char * s2) 581 { 582 int l1, l2; 583 584 l2 = strlen(s2); 585 if (!l2) 586 return (char *) s1; 587 l1 = strlen(s1); 588 while (l1 >= l2) { 589 l1--; 590 if (!memcmp(s1,s2,l2)) 591 return (char *) s1; 592 s1++; 593 } 594 return NULL; 595 } 596 #endif 597 598 #ifndef __HAVE_ARCH_MEMCHR 599 /** 600 * memchr - Find a character in an area of memory. 601 * @s: The memory area 602 * @c: The byte to search for 603 * @n: The size of the area. 604 * 605 * returns the address of the first occurrence of @c, or %NULL 606 * if @c is not found 607 */ 608 void *memchr(const void *s, int c, size_t n) 609 { 610 const unsigned char *p = s; 611 while (n-- != 0) { 612 if ((unsigned char)c == *p++) { 613 return (void *)(p-1); 614 } 615 } 616 return NULL; 617 } 618 619 #endif 620 #ifndef __HAVE_ARCH_MEMCHR_INV 621 static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) 622 { 623 while (bytes) { 624 if (*start != value) 625 return (void *)start; 626 start++; 627 bytes--; 628 } 629 return NULL; 630 } 631 /** 632 * memchr_inv - Find an unmatching character in an area of memory. 633 * @start: The memory area 634 * @c: Find a character other than c 635 * @bytes: The size of the area. 636 * 637 * returns the address of the first character other than @c, or %NULL 638 * if the whole buffer contains just @c. 639 */ 640 void *memchr_inv(const void *start, int c, size_t bytes) 641 { 642 u8 value = c; 643 u64 value64; 644 unsigned int words, prefix; 645 646 if (bytes <= 16) 647 return check_bytes8(start, value, bytes); 648 649 value64 = value; 650 value64 |= value64 << 8; 651 value64 |= value64 << 16; 652 value64 |= value64 << 32; 653 654 prefix = (unsigned long)start % 8; 655 if (prefix) { 656 u8 *r; 657 658 prefix = 8 - prefix; 659 r = check_bytes8(start, value, prefix); 660 if (r) 661 return r; 662 start += prefix; 663 bytes -= prefix; 664 } 665 666 words = bytes / 8; 667 668 while (words) { 669 if (*(u64 *)start != value64) 670 return check_bytes8(start, value, 8); 671 start += 8; 672 words--; 673 } 674 675 return check_bytes8(start, value, bytes % 8); 676 } 677 #endif 678