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 = 0; c2 = 0; 40 if (len) { 41 do { 42 c1 = *s1; c2 = *s2; 43 s1++; s2++; 44 if (!c1) 45 break; 46 if (!c2) 47 break; 48 if (c1 == c2) 49 continue; 50 c1 = tolower(c1); 51 c2 = tolower(c2); 52 if (c1 != c2) 53 break; 54 } while (--len); 55 } 56 return (int)c1 - (int)c2; 57 } 58 59 EXPORT_SYMBOL(strnicmp); 60 #endif 61 62 #ifndef __HAVE_ARCH_STRCPY 63 /** 64 * strcpy - Copy a %NUL terminated string 65 * @dest: Where to copy the string to 66 * @src: Where to copy the string from 67 */ 68 #undef strcpy 69 char * strcpy(char * dest,const char *src) 70 { 71 char *tmp = dest; 72 73 while ((*dest++ = *src++) != '\0') 74 /* nothing */; 75 return tmp; 76 } 77 EXPORT_SYMBOL(strcpy); 78 #endif 79 80 #ifndef __HAVE_ARCH_STRNCPY 81 /** 82 * strncpy - Copy a length-limited, %NUL-terminated string 83 * @dest: Where to copy the string to 84 * @src: Where to copy the string from 85 * @count: The maximum number of bytes to copy 86 * 87 * The result is not %NUL-terminated if the source exceeds 88 * @count bytes. 89 */ 90 char * strncpy(char * dest,const char *src,size_t count) 91 { 92 char *tmp = dest; 93 94 while (count) { 95 if ((*tmp = *src) != 0) src++; 96 tmp++; 97 count--; 98 } 99 return dest; 100 } 101 EXPORT_SYMBOL(strncpy); 102 #endif 103 104 #ifndef __HAVE_ARCH_STRLCPY 105 /** 106 * strlcpy - Copy a %NUL terminated string into a sized buffer 107 * @dest: Where to copy the string to 108 * @src: Where to copy the string from 109 * @size: size of destination buffer 110 * 111 * Compatible with *BSD: the result is always a valid 112 * NUL-terminated string that fits in the buffer (unless, 113 * of course, the buffer size is zero). It does not pad 114 * out the result like strncpy() does. 115 */ 116 size_t strlcpy(char *dest, const char *src, size_t size) 117 { 118 size_t ret = strlen(src); 119 120 if (size) { 121 size_t len = (ret >= size) ? size-1 : ret; 122 memcpy(dest, src, len); 123 dest[len] = '\0'; 124 } 125 return ret; 126 } 127 EXPORT_SYMBOL(strlcpy); 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 #undef strcat 137 char * strcat(char * dest, const char * src) 138 { 139 char *tmp = dest; 140 141 while (*dest) 142 dest++; 143 while ((*dest++ = *src++) != '\0') 144 ; 145 146 return tmp; 147 } 148 EXPORT_SYMBOL(strcat); 149 #endif 150 151 #ifndef __HAVE_ARCH_STRNCAT 152 /** 153 * strncat - Append a length-limited, %NUL-terminated string to another 154 * @dest: The string to be appended to 155 * @src: The string to append to it 156 * @count: The maximum numbers of bytes to copy 157 * 158 * Note that in contrast to strncpy, strncat ensures the result is 159 * terminated. 160 */ 161 char * strncat(char *dest, const char *src, size_t count) 162 { 163 char *tmp = dest; 164 165 if (count) { 166 while (*dest) 167 dest++; 168 while ((*dest++ = *src++) != 0) { 169 if (--count == 0) { 170 *dest = '\0'; 171 break; 172 } 173 } 174 } 175 176 return tmp; 177 } 178 EXPORT_SYMBOL(strncat); 179 #endif 180 181 #ifndef __HAVE_ARCH_STRLCAT 182 /** 183 * strlcat - Append a length-limited, %NUL-terminated string to another 184 * @dest: The string to be appended to 185 * @src: The string to append to it 186 * @count: The size of the destination buffer. 187 */ 188 size_t strlcat(char *dest, const char *src, size_t count) 189 { 190 size_t dsize = strlen(dest); 191 size_t len = strlen(src); 192 size_t res = dsize + len; 193 194 /* This would be a bug */ 195 BUG_ON(dsize >= count); 196 197 dest += dsize; 198 count -= dsize; 199 if (len >= count) 200 len = count-1; 201 memcpy(dest, src, len); 202 dest[len] = 0; 203 return res; 204 } 205 EXPORT_SYMBOL(strlcat); 206 #endif 207 208 #ifndef __HAVE_ARCH_STRCMP 209 /** 210 * strcmp - Compare two strings 211 * @cs: One string 212 * @ct: Another string 213 */ 214 #undef strcmp 215 int strcmp(const char * cs,const char * ct) 216 { 217 register signed char __res; 218 219 while (1) { 220 if ((__res = *cs - *ct++) != 0 || !*cs++) 221 break; 222 } 223 224 return __res; 225 } 226 EXPORT_SYMBOL(strcmp); 227 #endif 228 229 #ifndef __HAVE_ARCH_STRNCMP 230 /** 231 * strncmp - Compare two length-limited strings 232 * @cs: One string 233 * @ct: Another string 234 * @count: The maximum number of bytes to compare 235 */ 236 int strncmp(const char * cs,const char * ct,size_t count) 237 { 238 register signed char __res = 0; 239 240 while (count) { 241 if ((__res = *cs - *ct++) != 0 || !*cs++) 242 break; 243 count--; 244 } 245 246 return __res; 247 } 248 EXPORT_SYMBOL(strncmp); 249 #endif 250 251 #ifndef __HAVE_ARCH_STRCHR 252 /** 253 * strchr - Find the first occurrence of a character in a string 254 * @s: The string to be searched 255 * @c: The character to search for 256 */ 257 char * strchr(const char * s, int c) 258 { 259 for(; *s != (char) c; ++s) 260 if (*s == '\0') 261 return NULL; 262 return (char *) s; 263 } 264 EXPORT_SYMBOL(strchr); 265 #endif 266 267 #ifndef __HAVE_ARCH_STRRCHR 268 /** 269 * strrchr - Find the last occurrence of a character in a string 270 * @s: The string to be searched 271 * @c: The character to search for 272 */ 273 char * strrchr(const char * s, int c) 274 { 275 const char *p = s + strlen(s); 276 do { 277 if (*p == (char)c) 278 return (char *)p; 279 } while (--p >= s); 280 return NULL; 281 } 282 EXPORT_SYMBOL(strrchr); 283 #endif 284 285 #ifndef __HAVE_ARCH_STRNCHR 286 /** 287 * strnchr - Find a character in a length limited string 288 * @s: The string to be searched 289 * @count: The number of characters to be searched 290 * @c: The character to search for 291 */ 292 char *strnchr(const char *s, size_t count, int c) 293 { 294 for (; count-- && *s != '\0'; ++s) 295 if (*s == (char) c) 296 return (char *) s; 297 return NULL; 298 } 299 EXPORT_SYMBOL(strnchr); 300 #endif 301 302 #ifndef __HAVE_ARCH_STRLEN 303 /** 304 * strlen - Find the length of a string 305 * @s: The string to be sized 306 */ 307 size_t strlen(const char * s) 308 { 309 const char *sc; 310 311 for (sc = s; *sc != '\0'; ++sc) 312 /* nothing */; 313 return sc - s; 314 } 315 EXPORT_SYMBOL(strlen); 316 #endif 317 318 #ifndef __HAVE_ARCH_STRNLEN 319 /** 320 * strnlen - Find the length of a length-limited string 321 * @s: The string to be sized 322 * @count: The maximum number of bytes to search 323 */ 324 size_t strnlen(const char * s, size_t count) 325 { 326 const char *sc; 327 328 for (sc = s; count-- && *sc != '\0'; ++sc) 329 /* nothing */; 330 return sc - s; 331 } 332 EXPORT_SYMBOL(strnlen); 333 #endif 334 335 #ifndef __HAVE_ARCH_STRSPN 336 /** 337 * strspn - Calculate the length of the initial substring of @s which only 338 * contain letters in @accept 339 * @s: The string to be searched 340 * @accept: The string to search for 341 */ 342 size_t strspn(const char *s, const char *accept) 343 { 344 const char *p; 345 const char *a; 346 size_t count = 0; 347 348 for (p = s; *p != '\0'; ++p) { 349 for (a = accept; *a != '\0'; ++a) { 350 if (*p == *a) 351 break; 352 } 353 if (*a == '\0') 354 return count; 355 ++count; 356 } 357 358 return count; 359 } 360 361 EXPORT_SYMBOL(strspn); 362 #endif 363 364 /** 365 * strcspn - Calculate the length of the initial substring of @s which does 366 * not contain letters in @reject 367 * @s: The string to be searched 368 * @reject: The string to avoid 369 */ 370 size_t strcspn(const char *s, const char *reject) 371 { 372 const char *p; 373 const char *r; 374 size_t count = 0; 375 376 for (p = s; *p != '\0'; ++p) { 377 for (r = reject; *r != '\0'; ++r) { 378 if (*p == *r) 379 return count; 380 } 381 ++count; 382 } 383 384 return count; 385 } 386 EXPORT_SYMBOL(strcspn); 387 388 #ifndef __HAVE_ARCH_STRPBRK 389 /** 390 * strpbrk - Find the first occurrence of a set of characters 391 * @cs: The string to be searched 392 * @ct: The characters to search for 393 */ 394 char * strpbrk(const char * cs,const char * ct) 395 { 396 const char *sc1,*sc2; 397 398 for( sc1 = cs; *sc1 != '\0'; ++sc1) { 399 for( sc2 = ct; *sc2 != '\0'; ++sc2) { 400 if (*sc1 == *sc2) 401 return (char *) sc1; 402 } 403 } 404 return NULL; 405 } 406 EXPORT_SYMBOL(strpbrk); 407 #endif 408 409 #ifndef __HAVE_ARCH_STRSEP 410 /** 411 * strsep - Split a string into tokens 412 * @s: The string to be searched 413 * @ct: The characters to search for 414 * 415 * strsep() updates @s to point after the token, ready for the next call. 416 * 417 * It returns empty tokens, too, behaving exactly like the libc function 418 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. 419 * Same semantics, slimmer shape. ;) 420 */ 421 char * strsep(char **s, const char *ct) 422 { 423 char *sbegin = *s, *end; 424 425 if (sbegin == NULL) 426 return NULL; 427 428 end = strpbrk(sbegin, ct); 429 if (end) 430 *end++ = '\0'; 431 *s = end; 432 433 return sbegin; 434 } 435 436 EXPORT_SYMBOL(strsep); 437 #endif 438 439 #ifndef __HAVE_ARCH_MEMSET 440 /** 441 * memset - Fill a region of memory with the given value 442 * @s: Pointer to the start of the area. 443 * @c: The byte to fill the area with 444 * @count: The size of the area. 445 * 446 * Do not use memset() to access IO space, use memset_io() instead. 447 */ 448 void * memset(void * s,int c,size_t count) 449 { 450 char *xs = (char *) s; 451 452 while (count--) 453 *xs++ = c; 454 455 return s; 456 } 457 EXPORT_SYMBOL(memset); 458 #endif 459 460 #ifndef __HAVE_ARCH_MEMCPY 461 /** 462 * memcpy - Copy one area of memory to another 463 * @dest: Where to copy to 464 * @src: Where to copy from 465 * @count: The size of the area. 466 * 467 * You should not use this function to access IO space, use memcpy_toio() 468 * or memcpy_fromio() instead. 469 */ 470 void * memcpy(void * dest,const void *src,size_t count) 471 { 472 char *tmp = (char *) dest, *s = (char *) src; 473 474 while (count--) 475 *tmp++ = *s++; 476 477 return dest; 478 } 479 EXPORT_SYMBOL(memcpy); 480 #endif 481 482 #ifndef __HAVE_ARCH_MEMMOVE 483 /** 484 * memmove - Copy one area of memory to another 485 * @dest: Where to copy to 486 * @src: Where to copy from 487 * @count: The size of the area. 488 * 489 * Unlike memcpy(), memmove() copes with overlapping areas. 490 */ 491 void * memmove(void * dest,const void *src,size_t count) 492 { 493 char *tmp, *s; 494 495 if (dest <= src) { 496 tmp = (char *) dest; 497 s = (char *) src; 498 while (count--) 499 *tmp++ = *s++; 500 } 501 else { 502 tmp = (char *) dest + count; 503 s = (char *) src + count; 504 while (count--) 505 *--tmp = *--s; 506 } 507 508 return dest; 509 } 510 EXPORT_SYMBOL(memmove); 511 #endif 512 513 #ifndef __HAVE_ARCH_MEMCMP 514 /** 515 * memcmp - Compare two areas of memory 516 * @cs: One area of memory 517 * @ct: Another area of memory 518 * @count: The size of the area. 519 */ 520 #undef memcmp 521 int memcmp(const void * cs,const void * ct,size_t count) 522 { 523 const unsigned char *su1, *su2; 524 int res = 0; 525 526 for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) 527 if ((res = *su1 - *su2) != 0) 528 break; 529 return res; 530 } 531 EXPORT_SYMBOL(memcmp); 532 #endif 533 534 #ifndef __HAVE_ARCH_MEMSCAN 535 /** 536 * memscan - Find a character in an area of memory. 537 * @addr: The memory area 538 * @c: The byte to search for 539 * @size: The size of the area. 540 * 541 * returns the address of the first occurrence of @c, or 1 byte past 542 * the area if @c is not found 543 */ 544 void * memscan(void * addr, int c, size_t size) 545 { 546 unsigned char * p = (unsigned char *) addr; 547 548 while (size) { 549 if (*p == c) 550 return (void *) p; 551 p++; 552 size--; 553 } 554 return (void *) p; 555 } 556 EXPORT_SYMBOL(memscan); 557 #endif 558 559 #ifndef __HAVE_ARCH_STRSTR 560 /** 561 * strstr - Find the first substring in a %NUL terminated string 562 * @s1: The string to be searched 563 * @s2: The string to search for 564 */ 565 char * strstr(const char * s1,const char * s2) 566 { 567 int l1, l2; 568 569 l2 = strlen(s2); 570 if (!l2) 571 return (char *) s1; 572 l1 = strlen(s1); 573 while (l1 >= l2) { 574 l1--; 575 if (!memcmp(s1,s2,l2)) 576 return (char *) s1; 577 s1++; 578 } 579 return NULL; 580 } 581 EXPORT_SYMBOL(strstr); 582 #endif 583 584 #ifndef __HAVE_ARCH_MEMCHR 585 /** 586 * memchr - Find a character in an area of memory. 587 * @s: The memory area 588 * @c: The byte to search for 589 * @n: The size of the area. 590 * 591 * returns the address of the first occurrence of @c, or %NULL 592 * if @c is not found 593 */ 594 void *memchr(const void *s, int c, size_t n) 595 { 596 const unsigned char *p = s; 597 while (n-- != 0) { 598 if ((unsigned char)c == *p++) { 599 return (void *)(p-1); 600 } 601 } 602 return NULL; 603 } 604 EXPORT_SYMBOL(memchr); 605 #endif 606