src/core/string.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 2004 Tobias Lorenz
   4  *
   5  *  string handling functions
   6  *  based on linux/lib/string.c
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 /*
  14  * stupid library routines.. The optimized versions should generally be found
  15  * as inline code in <asm-xx/string.h>
  16  *
  17  * These are buggy as well..
  18  *
  19  * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de>
  20  * -  Added strsep() which will replace strtok() soon (because strsep() is
  21  *    reentrant and should be faster). Use only strsep() in new code, please.
  22  */
  23
  24 #include <stdint.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28
  29 /* *** FROM string.c *** */
  30
  31 #ifndef __HAVE_ARCH_STRNICMP
  32 /**
  33  * strnicmp - Case insensitive, length-limited string comparison
  34  * @s1: One string
  35  * @s2: The other string
  36  * @len: the maximum number of characters to compare
  37  */
  38 int strnicmp(const char *s1, const char *s2, size_t len)
  39 {
  40         /* Yes, Virginia, it had better be unsigned */
  41         unsigned char c1, c2;
  42
  43         c1 = 0; c2 = 0;
  44         if (len) {
  45                 do {
  46                         c1 = *s1; c2 = *s2;
  47                         s1++; s2++;
  48                         if (!c1)
  49                                 break;
  50                         if (!c2)
  51                                 break;
  52                         if (c1 == c2)
  53                                 continue;
  54                         c1 = tolower(c1);
  55                         c2 = tolower(c2);
  56                         if (c1 != c2)
  57                                 break;
  58                 } while (--len);
  59         }
  60         return (int)c1 - (int)c2;
  61 }
  62 #endif
  63
  64 char * ___strtok;
  65
  66 #ifndef __HAVE_ARCH_STRCPY
  67 /**
  68  * strcpy - Copy a %NUL terminated string
  69  * @dest: Where to copy the string to
  70  * @src: Where to copy the string from
  71  */
  72 char * strcpy(char * dest,const char *src)
  73 {
  74         char *tmp = dest;
  75
  76         while ((*dest++ = *src++) != '\0')
  77                 /* nothing */;
  78         return tmp;
  79 }
  80 #endif
  81
  82 #ifndef __HAVE_ARCH_STRNCPY
  83 /**
  84  * strncpy - Copy a length-limited, %NUL-terminated string
  85  * @dest: Where to copy the string to
  86  * @src: Where to copy the string from
  87  * @count: The maximum number of bytes to copy
  88  *
  89  * Note that unlike userspace strncpy, this does not %NUL-pad the buffer.
  90  * However, the result is not %NUL-terminated if the source exceeds
  91  * @count bytes.
  92  */
  93 char * strncpy(char * dest,const char *src,size_t count)
  94 {
  95         char *tmp = dest;
  96
  97         while (count-- && (*dest++ = *src++) != '\0')
  98                 /* nothing */;
  99
 100         return tmp;
 101 }
 102 #endif
 103
 104 #ifndef __HAVE_ARCH_STRCAT
 105 /**
 106  * strcat - Append one %NUL-terminated string to another
 107  * @dest: The string to be appended to
 108  * @src: The string to append to it
 109  */
 110 char * strcat(char * dest, const char * src)
 111 {
 112         char *tmp = dest;
 113
 114         while (*dest)
 115                 dest++;
 116         while ((*dest++ = *src++) != '\0')
 117                 ;
 118
 119         return tmp;
 120 }
 121 #endif
 122
 123 #ifndef __HAVE_ARCH_STRNCAT
 124 /**
 125  * strncat - Append a length-limited, %NUL-terminated string to another
 126  * @dest: The string to be appended to
 127  * @src: The string to append to it
 128  * @count: The maximum numbers of bytes to copy
 129  *
 130  * Note that in contrast to strncpy, strncat ensures the result is
 131  * terminated.
 132  */
 133 char * strncat(char *dest, const char *src, size_t count)
 134 {
 135         char *tmp = dest;
 136
 137         if (count) {
 138                 while (*dest)
 139                         dest++;
 140                 while ((*dest++ = *src++)) {
 141                         if (--count == 0) {
 142                                 *dest = '\0';
 143                                 break;
 144                         }
 145                 }
 146         }
 147
 148         return tmp;
 149 }
 150 #endif
 151
 152 #ifndef __HAVE_ARCH_STRCMP
 153 /**
 154  * strcmp - Compare two strings
 155  * @cs: One string
 156  * @ct: Another string
 157  */
 158 int strcmp(const char * cs,const char * ct)
 159 {
 160         register signed char __res;
 161
 162         while (1) {
 163                 if ((__res = *cs - *ct++) != 0 || !*cs++)
 164                         break;
 165         }
 166
 167         return __res;
 168 }
 169 #endif
 170
 171 #ifndef __HAVE_ARCH_STRNCMP
 172 /**
 173  * strncmp - Compare two length-limited strings
 174  * @cs: One string
 175  * @ct: Another string
 176  * @count: The maximum number of bytes to compare
 177  */
 178 int strncmp(const char * cs,const char * ct,size_t count)
 179 {
 180         register signed char __res = 0;
 181
 182         while (count) {
 183                 if ((__res = *cs - *ct++) != 0 || !*cs++)
 184                         break;
 185                 count--;
 186         }
 187
 188         return __res;
 189 }
 190 #endif
 191
 192 #ifndef __HAVE_ARCH_STRCHR
 193 /**
 194  * strchr - Find the first occurrence of a character in a string
 195  * @s: The string to be searched
 196  * @c: The character to search for
 197  */
 198 char * strchr(const char * s, int c)
 199 {
 200         for(; *s != (char) c; ++s)
 201                 if (*s == '\0')
 202                         return NULL;
 203         return (char *) s;
 204 }
 205 #endif
 206
 207 #ifndef __HAVE_ARCH_STRRCHR
 208 /**
 209  * strrchr - Find the last occurrence of a character in a string
 210  * @s: The string to be searched
 211  * @c: The character to search for
 212  */
 213 char * strrchr(const char * s, int c)
 214 {
 215        const char *p = s + strlen(s);
 216        do {
 217            if (*p == (char)c)
 218                return (char *)p;
 219        } while (--p >= s);
 220        return NULL;
 221 }
 222 #endif
 223
 224 #ifndef __HAVE_ARCH_STRLEN
 225 /**
 226  * strlen - Find the length of a string
 227  * @s: The string to be sized
 228  */
 229 size_t strlen(const char * s)
 230 {
 231         const char *sc;
 232
 233         for (sc = s; *sc != '\0'; ++sc)
 234                 /* nothing */;
 235         return sc - s;
 236 }
 237 #endif
 238
 239 #ifndef __HAVE_ARCH_STRNLEN
 240 /**
 241  * strnlen - Find the length of a length-limited string
 242  * @s: The string to be sized
 243  * @count: The maximum number of bytes to search
 244  */
 245 size_t strnlen(const char * s, size_t count)
 246 {
 247         const char *sc;
 248
 249         for (sc = s; count-- && *sc != '\0'; ++sc)
 250                 /* nothing */;
 251         return sc - s;
 252 }
 253 #endif
 254
 255 #ifndef __HAVE_ARCH_STRSPN
 256 /**
 257  * strspn - Calculate the length of the initial substring of @s which only
 258  *      contain letters in @accept
 259  * @s: The string to be searched
 260  * @accept: The string to search for
 261  */
 262 size_t strspn(const char *s, const char *accept)
 263 {
 264         const char *p;
 265         const char *a;
 266         size_t count = 0;
 267
 268         for (p = s; *p != '\0'; ++p) {
 269                 for (a = accept; *a != '\0'; ++a) {
 270                         if (*p == *a)
 271                                 break;
 272                 }
 273                 if (*a == '\0')
 274                         return count;
 275                 ++count;
 276         }
 277
 278         return count;
 279 }
 280 #endif
 281
 282 #ifndef __HAVE_ARCH_STRPBRK
 283 /**
 284  * strpbrk - Find the first occurrence of a set of characters
 285  * @cs: The string to be searched
 286  * @ct: The characters to search for
 287  */
 288 char * strpbrk(const char * cs,const char * ct)
 289 {
 290         const char *sc1,*sc2;
 291
 292         for( sc1 = cs; *sc1 != '\0'; ++sc1) {
 293                 for( sc2 = ct; *sc2 != '\0'; ++sc2) {
 294                         if (*sc1 == *sc2)
 295                                 return (char *) sc1;
 296                 }
 297         }
 298         return NULL;
 299 }
 300 #endif
 301
 302 #ifndef __HAVE_ARCH_STRTOK
 303 /**
 304  * strtok - Split a string into tokens
 305  * @s: The string to be searched
 306  * @ct: The characters to search for
 307  *
 308  * WARNING: strtok is deprecated, use strsep instead.
 309  */
 310 char * strtok(char * s,const char * ct)
 311 {
 312         char *sbegin, *send;
 313
 314         sbegin  = s ? s : ___strtok;
 315         if (!sbegin) {
 316                 return NULL;
 317         }
 318         sbegin += strspn(sbegin,ct);
 319         if (*sbegin == '\0') {
 320                 ___strtok = NULL;
 321                 return( NULL );
 322         }
 323         send = strpbrk( sbegin, ct);
 324         if (send && *send != '\0')
 325                 *send++ = '\0';
 326         ___strtok = send;
 327         return (sbegin);
 328 }
 329 #endif
 330
 331 #ifndef __HAVE_ARCH_STRSEP
 332 /**
 333  * strsep - Split a string into tokens
 334  * @s: The string to be searched
 335  * @ct: The characters to search for
 336  *
 337  * strsep() updates @s to point after the token, ready for the next call.
 338  *
 339  * It returns empty tokens, too, behaving exactly like the libc function
 340  * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
 341  * Same semantics, slimmer shape. ;)
 342  */
 343 char * strsep(char **s, const char *ct)
 344 {
 345         char *sbegin = *s, *end;
 346
 347         if (sbegin == NULL)
 348                 return NULL;
 349
 350         end = strpbrk(sbegin, ct);
 351         if (end)
 352                 *end++ = '\0';
 353         *s = end;
 354
 355         return sbegin;
 356 }
 357 #endif
 358
 359 #ifndef __HAVE_ARCH_MEMSET
 360 /**
 361  * memset - Fill a region of memory with the given value
 362  * @s: Pointer to the start of the area.
 363  * @c: The byte to fill the area with
 364  * @count: The size of the area.
 365  *
 366  * Do not use memset() to access IO space, use memset_io() instead.
 367  */
 368 void * memset(void * s,int c,size_t count)
 369 {
 370         char *xs = (char *) s;
 371
 372         while (count--)
 373                 *xs++ = c;
 374
 375         return s;
 376 }
 377 #endif
 378
 379 #ifndef __HAVE_ARCH_BCOPY
 380 /**
 381  * bcopy - Copy one area of memory to another
 382  * @src: Where to copy from
 383  * @dest: Where to copy to
 384  * @count: The size of the area.
 385  *
 386  * Note that this is the same as memcpy(), with the arguments reversed.
 387  * memcpy() is the standard, bcopy() is a legacy BSD function.
 388  *
 389  * You should not use this function to access IO space, use memcpy_toio()
 390  * or memcpy_fromio() instead.
 391  */
 392 char * bcopy(const char * src, char * dest, int count)
 393 {
 394         char *tmp = dest;
 395
 396         while (count--)
 397                 *tmp++ = *src++;
 398
 399         return dest;
 400 }
 401 #endif
 402
 403 #ifndef __HAVE_ARCH_MEMCPY
 404 /**
 405  * memcpy - Copy one area of memory to another
 406  * @dest: Where to copy to
 407  * @src: Where to copy from
 408  * @count: The size of the area.
 409  *
 410  * You should not use this function to access IO space, use memcpy_toio()
 411  * or memcpy_fromio() instead.
 412  */
 413 void * memcpy(void * dest,const void *src,size_t count)
 414 {
 415         char *tmp = (char *) dest, *s = (char *) src;
 416
 417         while (count--)
 418                 *tmp++ = *s++;
 419
 420         return dest;
 421 }
 422 #endif
 423
 424 #ifndef __HAVE_ARCH_MEMMOVE
 425 /**
 426  * memmove - Copy one area of memory to another
 427  * @dest: Where to copy to
 428  * @src: Where to copy from
 429  * @count: The size of the area.
 430  *
 431  * Unlike memcpy(), memmove() copes with overlapping areas.
 432  */
 433 void * memmove(void * dest,const void *src,size_t count)
 434 {
 435         char *tmp, *s;
 436
 437         if (dest <= src) {
 438                 tmp = (char *) dest;
 439                 s = (char *) src;
 440                 while (count--)
 441                         *tmp++ = *s++;
 442                 }
 443         else {
 444                 tmp = (char *) dest + count;
 445                 s = (char *) src + count;
 446                 while (count--)
 447                         *--tmp = *--s;
 448                 }
 449
 450         return dest;
 451 }
 452 #endif
 453
 454 #ifndef __HAVE_ARCH_MEMCMP
 455 /**
 456  * memcmp - Compare two areas of memory
 457  * @cs: One area of memory
 458  * @ct: Another area of memory
 459  * @count: The size of the area.
 460  */
 461 int memcmp(const void * cs,const void * ct,size_t count)
 462 {
 463         const unsigned char *su1, *su2;
 464         int res = 0;
 465
 466         for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
 467                 if ((res = *su1 - *su2) != 0)
 468                         break;
 469         return res;
 470 }
 471 #endif
 472
 473 #ifndef __HAVE_ARCH_MEMSCAN
 474 /**
 475  * memscan - Find a character in an area of memory.
 476  * @addr: The memory area
 477  * @c: The byte to search for
 478  * @size: The size of the area.
 479  *
 480  * returns the address of the first occurrence of @c, or 1 byte past
 481  * the area if @c is not found
 482  */
 483 void * memscan(void * addr, int c, size_t size)
 484 {
 485         unsigned char * p = (unsigned char *) addr;
 486
 487         while (size) {
 488                 if (*p == c)
 489                         return (void *) p;
 490                 p++;
 491                 size--;
 492         }
 493         return (void *) p;
 494 }
 495 #endif
 496
 497 #ifndef __HAVE_ARCH_STRSTR
 498 /**
 499  * strstr - Find the first substring in a %NUL terminated string
 500  * @s1: The string to be searched
 501  * @s2: The string to search for
 502  */
 503 char * strstr(const char * s1,const char * s2)
 504 {
 505         int l1, l2;
 506
 507         l2 = strlen(s2);
 508         if (!l2)
 509                 return (char *) s1;
 510         l1 = strlen(s1);
 511         while (l1 >= l2) {
 512                 l1--;
 513                 if (!memcmp(s1,s2,l2))
 514                         return (char *) s1;
 515                 s1++;
 516         }
 517         return NULL;
 518 }
 519 #endif
 520
 521 #ifndef __HAVE_ARCH_MEMCHR
 522 /**
 523  * memchr - Find a character in an area of memory.
 524  * @s: The memory area
 525  * @c: The byte to search for
 526  * @n: The size of the area.
 527  *
 528  * returns the address of the first occurrence of @c, or %NULL
 529  * if @c is not found
 530  */
 531 void * memchr(const void *s, int c, size_t n)
 532 {
 533         const unsigned char *p = s;
 534         while (n-- != 0) {
 535                 if ((unsigned char)c == *p++) {
 536                         return (void *)(p-1);
 537                 }
 538         }
 539         return NULL;
 540 }
 541
 542 #endif
 543
 544 char * strdup(const char *s) {
 545         char *new = malloc(strlen(s)+1);
 546         if (new)
 547                 strcpy(new,s);
 548         return new;
 549 }