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 224 225 226 /** 227 * skip_spaces - Removes leading whitespace from @str. 228 * @str: The string to be stripped. 229 * 230 * Returns a pointer to the first non-whitespace character in @str. 231 */ 232 char *skip_spaces(const char *str) 233 { 234 while (isspace(*str)) 235 ++str; 236 return (char *)str; 237 } 238 239 /** 240 * strim - Removes leading and trailing whitespace from @s. 241 * @s: The string to be stripped. 242 * 243 * Note that the first trailing whitespace is replaced with a %NUL-terminator 244 * in the given string @s. Returns a pointer to the first non-whitespace 245 * character in @s. 246 */ 247 char *strim(char *s) 248 { 249 size_t size; 250 char *end; 251 252 s = skip_spaces(s); 253 size = strlen(s); 254 if (!size) 255 return s; 256 257 end = s + size - 1; 258 while (end >= s && isspace(*end)) 259 end--; 260 *(end + 1) = '\0'; 261 262 return s; 263 } 264 #ifndef __HAVE_ARCH_STRLEN 265 /** 266 * strlen - Find the length of a string 267 * @s: The string to be sized 268 */ 269 size_t strlen(const char * s) 270 { 271 const char *sc; 272 273 for (sc = s; *sc != '\0'; ++sc) 274 /* nothing */; 275 return sc - s; 276 } 277 #endif 278 279 #ifndef __HAVE_ARCH_STRNLEN 280 /** 281 * strnlen - Find the length of a length-limited string 282 * @s: The string to be sized 283 * @count: The maximum number of bytes to search 284 */ 285 size_t strnlen(const char * s, size_t count) 286 { 287 const char *sc; 288 289 for (sc = s; count-- && *sc != '\0'; ++sc) 290 /* nothing */; 291 return sc - s; 292 } 293 #endif 294 295 #ifndef __HAVE_ARCH_STRDUP 296 char * strdup(const char *s) 297 { 298 char *new; 299 300 if ((s == NULL) || 301 ((new = malloc (strlen(s) + 1)) == NULL) ) { 302 return NULL; 303 } 304 305 strcpy (new, s); 306 return new; 307 } 308 #endif 309 310 #ifndef __HAVE_ARCH_STRSPN 311 /** 312 * strspn - Calculate the length of the initial substring of @s which only 313 * contain letters in @accept 314 * @s: The string to be searched 315 * @accept: The string to search for 316 */ 317 size_t strspn(const char *s, const char *accept) 318 { 319 const char *p; 320 const char *a; 321 size_t count = 0; 322 323 for (p = s; *p != '\0'; ++p) { 324 for (a = accept; *a != '\0'; ++a) { 325 if (*p == *a) 326 break; 327 } 328 if (*a == '\0') 329 return count; 330 ++count; 331 } 332 333 return count; 334 } 335 #endif 336 337 #ifndef __HAVE_ARCH_STRPBRK 338 /** 339 * strpbrk - Find the first occurrence of a set of characters 340 * @cs: The string to be searched 341 * @ct: The characters to search for 342 */ 343 char * strpbrk(const char * cs,const char * ct) 344 { 345 const char *sc1,*sc2; 346 347 for( sc1 = cs; *sc1 != '\0'; ++sc1) { 348 for( sc2 = ct; *sc2 != '\0'; ++sc2) { 349 if (*sc1 == *sc2) 350 return (char *) sc1; 351 } 352 } 353 return NULL; 354 } 355 #endif 356 357 #ifndef __HAVE_ARCH_STRTOK 358 /** 359 * strtok - Split a string into tokens 360 * @s: The string to be searched 361 * @ct: The characters to search for 362 * 363 * WARNING: strtok is deprecated, use strsep instead. 364 */ 365 char * strtok(char * s,const char * ct) 366 { 367 char *sbegin, *send; 368 369 sbegin = s ? s : ___strtok; 370 if (!sbegin) { 371 return NULL; 372 } 373 sbegin += strspn(sbegin,ct); 374 if (*sbegin == '\0') { 375 ___strtok = NULL; 376 return( NULL ); 377 } 378 send = strpbrk( sbegin, ct); 379 if (send && *send != '\0') 380 *send++ = '\0'; 381 ___strtok = send; 382 return (sbegin); 383 } 384 #endif 385 386 #ifndef __HAVE_ARCH_STRSEP 387 /** 388 * strsep - Split a string into tokens 389 * @s: The string to be searched 390 * @ct: The characters to search for 391 * 392 * strsep() updates @s to point after the token, ready for the next call. 393 * 394 * It returns empty tokens, too, behaving exactly like the libc function 395 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. 396 * Same semantics, slimmer shape. ;) 397 */ 398 char * strsep(char **s, const char *ct) 399 { 400 char *sbegin = *s, *end; 401 402 if (sbegin == NULL) 403 return NULL; 404 405 end = strpbrk(sbegin, ct); 406 if (end) 407 *end++ = '\0'; 408 *s = end; 409 410 return sbegin; 411 } 412 #endif 413 414 #ifndef __HAVE_ARCH_STRSWAB 415 /** 416 * strswab - swap adjacent even and odd bytes in %NUL-terminated string 417 * s: address of the string 418 * 419 * returns the address of the swapped string or NULL on error. If 420 * string length is odd, last byte is untouched. 421 */ 422 char *strswab(const char *s) 423 { 424 char *p, *q; 425 426 if ((NULL == s) || ('\0' == *s)) { 427 return (NULL); 428 } 429 430 for (p=(char *)s, q=p+1; (*p != '\0') && (*q != '\0'); p+=2, q+=2) { 431 char tmp; 432 433 tmp = *p; 434 *p = *q; 435 *q = tmp; 436 } 437 438 return (char *) s; 439 } 440 #endif 441 442 #ifndef __HAVE_ARCH_MEMSET 443 /** 444 * memset - Fill a region of memory with the given value 445 * @s: Pointer to the start of the area. 446 * @c: The byte to fill the area with 447 * @count: The size of the area. 448 * 449 * Do not use memset() to access IO space, use memset_io() instead. 450 */ 451 void * memset(void * s,int c,size_t count) 452 { 453 unsigned long *sl = (unsigned long *) s; 454 unsigned long cl = 0; 455 char *s8; 456 int i; 457 458 /* do it one word at a time (32 bits or 64 bits) while possible */ 459 if ( ((ulong)s & (sizeof(*sl) - 1)) == 0) { 460 for (i = 0; i < sizeof(*sl); i++) { 461 cl <<= 8; 462 cl |= c & 0xff; 463 } 464 while (count >= sizeof(*sl)) { 465 *sl++ = cl; 466 count -= sizeof(*sl); 467 } 468 } 469 /* fill 8 bits at a time */ 470 s8 = (char *)sl; 471 while (count--) 472 *s8++ = c; 473 474 return s; 475 } 476 #endif 477 478 #ifndef __HAVE_ARCH_BCOPY 479 /** 480 * bcopy - Copy one area of memory to another 481 * @src: Where to copy from 482 * @dest: Where to copy to 483 * @count: The size of the area. 484 * 485 * Note that this is the same as memcpy(), with the arguments reversed. 486 * memcpy() is the standard, bcopy() is a legacy BSD function. 487 * 488 * You should not use this function to access IO space, use memcpy_toio() 489 * or memcpy_fromio() instead. 490 */ 491 char * bcopy(const char * src, char * dest, int count) 492 { 493 char *tmp = dest; 494 495 while (count--) 496 *tmp++ = *src++; 497 498 return dest; 499 } 500 #endif 501 502 #ifndef __HAVE_ARCH_MEMCPY 503 /** 504 * memcpy - Copy one area of memory to another 505 * @dest: Where to copy to 506 * @src: Where to copy from 507 * @count: The size of the area. 508 * 509 * You should not use this function to access IO space, use memcpy_toio() 510 * or memcpy_fromio() instead. 511 */ 512 void * memcpy(void *dest, const void *src, size_t count) 513 { 514 unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src; 515 char *d8, *s8; 516 517 if (src == dest) 518 return dest; 519 520 /* while all data is aligned (common case), copy a word at a time */ 521 if ( (((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) { 522 while (count >= sizeof(*dl)) { 523 *dl++ = *sl++; 524 count -= sizeof(*dl); 525 } 526 } 527 /* copy the reset one byte at a time */ 528 d8 = (char *)dl; 529 s8 = (char *)sl; 530 while (count--) 531 *d8++ = *s8++; 532 533 return dest; 534 } 535 #endif 536 537 #ifndef __HAVE_ARCH_MEMMOVE 538 /** 539 * memmove - Copy one area of memory to another 540 * @dest: Where to copy to 541 * @src: Where to copy from 542 * @count: The size of the area. 543 * 544 * Unlike memcpy(), memmove() copes with overlapping areas. 545 */ 546 void * memmove(void * dest,const void *src,size_t count) 547 { 548 char *tmp, *s; 549 550 if (src == dest) 551 return dest; 552 553 if (dest <= src) { 554 tmp = (char *) dest; 555 s = (char *) src; 556 while (count--) 557 *tmp++ = *s++; 558 } 559 else { 560 tmp = (char *) dest + count; 561 s = (char *) src + count; 562 while (count--) 563 *--tmp = *--s; 564 } 565 566 return dest; 567 } 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 int memcmp(const void * cs,const void * ct,size_t count) 578 { 579 const unsigned char *su1, *su2; 580 int res = 0; 581 582 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) 583 if ((res = *su1 - *su2) != 0) 584 break; 585 return res; 586 } 587 #endif 588 589 #ifndef __HAVE_ARCH_MEMSCAN 590 /** 591 * memscan - Find a character in an area of memory. 592 * @addr: The memory area 593 * @c: The byte to search for 594 * @size: The size of the area. 595 * 596 * returns the address of the first occurrence of @c, or 1 byte past 597 * the area if @c is not found 598 */ 599 void * memscan(void * addr, int c, size_t size) 600 { 601 unsigned char * p = (unsigned char *) addr; 602 603 while (size) { 604 if (*p == c) 605 return (void *) p; 606 p++; 607 size--; 608 } 609 return (void *) p; 610 } 611 #endif 612 613 #ifndef __HAVE_ARCH_STRSTR 614 /** 615 * strstr - Find the first substring in a %NUL terminated string 616 * @s1: The string to be searched 617 * @s2: The string to search for 618 */ 619 char * strstr(const char * s1,const char * s2) 620 { 621 int l1, l2; 622 623 l2 = strlen(s2); 624 if (!l2) 625 return (char *) s1; 626 l1 = strlen(s1); 627 while (l1 >= l2) { 628 l1--; 629 if (!memcmp(s1,s2,l2)) 630 return (char *) s1; 631 s1++; 632 } 633 return NULL; 634 } 635 #endif 636 637 #ifndef __HAVE_ARCH_MEMCHR 638 /** 639 * memchr - Find a character in an area of memory. 640 * @s: The memory area 641 * @c: The byte to search for 642 * @n: The size of the area. 643 * 644 * returns the address of the first occurrence of @c, or %NULL 645 * if @c is not found 646 */ 647 void *memchr(const void *s, int c, size_t n) 648 { 649 const unsigned char *p = s; 650 while (n-- != 0) { 651 if ((unsigned char)c == *p++) { 652 return (void *)(p-1); 653 } 654 } 655 return NULL; 656 } 657 658 #endif 659