string.c 11.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605
/*
 *  linux/lib/string.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/*
 * stupid library routines.. The optimized versions should generally be found
 * as inline code in <asm-xx/string.h>
 *
 * These are buggy as well..
 *
 * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de>
 * -  Added strsep() which will replace strtok() soon (because strsep() is
 *    reentrant and should be faster). Use only strsep() in new code, please.
 */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <malloc.h>


#if 0 /* not used - was: #ifndef __HAVE_ARCH_STRNICMP */
/**
 * strnicmp - Case insensitive, length-limited string comparison
 * @s1: One string
 * @s2: The other string
 * @len: the maximum number of characters to compare
 */
int strnicmp(const char *s1, const char *s2, size_t len)
{
	/* Yes, Virginia, it had better be unsigned */
	unsigned char c1, c2;

	c1 = 0;	c2 = 0;
	if (len) {
		do {
			c1 = *s1; c2 = *s2;
			s1++; s2++;
			if (!c1)
				break;
			if (!c2)
				break;
			if (c1 == c2)
				continue;
			c1 = tolower(c1);
			c2 = tolower(c2);
			if (c1 != c2)
				break;
		} while (--len);
	}
	return (int)c1 - (int)c2;
}
#endif

char * ___strtok;

#ifndef __HAVE_ARCH_STRCPY
/**
 * strcpy - Copy a %NUL terminated string
 * @dest: Where to copy the string to
 * @src: Where to copy the string from
 */
char * strcpy(char * dest,const char *src)
{
	char *tmp = dest;

	while ((*dest++ = *src++) != '\0')
		/* nothing */;
	return tmp;
}
#endif

#ifndef __HAVE_ARCH_STRNCPY
/**
 * strncpy - Copy a length-limited, %NUL-terminated string
 * @dest: Where to copy the string to
 * @src: Where to copy the string from
 * @count: The maximum number of bytes to copy
 *
 * Note that unlike userspace strncpy, this does not %NUL-pad the buffer.
 * However, the result is not %NUL-terminated if the source exceeds
 * @count bytes.
 */
char * strncpy(char * dest,const char *src,size_t count)
{
	char *tmp = dest;

	while (count-- && (*dest++ = *src++) != '\0')
		/* nothing */;

	return tmp;
}
#endif

#ifndef __HAVE_ARCH_STRCAT
/**
 * strcat - Append one %NUL-terminated string to another
 * @dest: The string to be appended to
 * @src: The string to append to it
 */
char * strcat(char * dest, const char * src)
{
	char *tmp = dest;

	while (*dest)
		dest++;
	while ((*dest++ = *src++) != '\0')
		;

	return tmp;
}
#endif

#ifndef __HAVE_ARCH_STRNCAT
/**
 * strncat - Append a length-limited, %NUL-terminated string to another
 * @dest: The string to be appended to
 * @src: The string to append to it
 * @count: The maximum numbers of bytes to copy
 *
 * Note that in contrast to strncpy, strncat ensures the result is
 * terminated.
 */
char * strncat(char *dest, const char *src, size_t count)
{
	char *tmp = dest;

	if (count) {
		while (*dest)
			dest++;
		while ((*dest++ = *src++)) {
			if (--count == 0) {
				*dest = '\0';
				break;
			}
		}
	}

	return tmp;
}
#endif

#ifndef __HAVE_ARCH_STRCMP
/**
 * strcmp - Compare two strings
 * @cs: One string
 * @ct: Another string
 */
int strcmp(const char * cs,const char * ct)
{
	register signed char __res;

	while (1) {
		if ((__res = *cs - *ct++) != 0 || !*cs++)
			break;
	}

	return __res;
}
#endif

#ifndef __HAVE_ARCH_STRNCMP
/**
 * strncmp - Compare two length-limited strings
 * @cs: One string
 * @ct: Another string
 * @count: The maximum number of bytes to compare
 */
int strncmp(const char * cs,const char * ct,size_t count)
{
	register signed char __res = 0;

	while (count) {
		if ((__res = *cs - *ct++) != 0 || !*cs++)
			break;
		count--;
	}

	return __res;
}
#endif

#ifndef __HAVE_ARCH_STRCHR
/**
 * strchr - Find the first occurrence of a character in a string
 * @s: The string to be searched
 * @c: The character to search for
 */
char * strchr(const char * s, int c)
{
	for(; *s != (char) c; ++s)
		if (*s == '\0')
			return NULL;
	return (char *) s;
}
#endif

#ifndef __HAVE_ARCH_STRRCHR
/**
 * strrchr - Find the last occurrence of a character in a string
 * @s: The string to be searched
 * @c: The character to search for
 */
char * strrchr(const char * s, int c)
{
       const char *p = s + strlen(s);
       do {
	   if (*p == (char)c)
	       return (char *)p;
       } while (--p >= s);
       return NULL;
}
#endif

#ifndef __HAVE_ARCH_STRLEN
/**
 * strlen - Find the length of a string
 * @s: The string to be sized
 */
size_t strlen(const char * s)
{
	const char *sc;

	for (sc = s; *sc != '\0'; ++sc)
		/* nothing */;
	return sc - s;
}
#endif

#ifndef __HAVE_ARCH_STRNLEN
/**
 * strnlen - Find the length of a length-limited string
 * @s: The string to be sized
 * @count: The maximum number of bytes to search
 */
size_t strnlen(const char * s, size_t count)
{
	const char *sc;

	for (sc = s; count-- && *sc != '\0'; ++sc)
		/* nothing */;
	return sc - s;
}
#endif

#ifndef __HAVE_ARCH_STRDUP
char * strdup(const char *s)
{
	char *new;

	if ((s == NULL)	||
	    ((new = malloc (strlen(s) + 1)) == NULL) ) {
		return NULL;
	}

	strcpy (new, s);
	return new;
}
#endif

#ifndef __HAVE_ARCH_STRSPN
/**
 * strspn - Calculate the length of the initial substring of @s which only
 *	contain letters in @accept
 * @s: The string to be searched
 * @accept: The string to search for
 */
size_t strspn(const char *s, const char *accept)
{
	const char *p;
	const char *a;
	size_t count = 0;

	for (p = s; *p != '\0'; ++p) {
		for (a = accept; *a != '\0'; ++a) {
			if (*p == *a)
				break;
		}
		if (*a == '\0')
			return count;
		++count;
	}

	return count;
}
#endif

#ifndef __HAVE_ARCH_STRPBRK
/**
 * strpbrk - Find the first occurrence of a set of characters
 * @cs: The string to be searched
 * @ct: The characters to search for
 */
char * strpbrk(const char * cs,const char * ct)
{
	const char *sc1,*sc2;

	for( sc1 = cs; *sc1 != '\0'; ++sc1) {
		for( sc2 = ct; *sc2 != '\0'; ++sc2) {
			if (*sc1 == *sc2)
				return (char *) sc1;
		}
	}
	return NULL;
}
#endif

#ifndef __HAVE_ARCH_STRTOK
/**
 * strtok - Split a string into tokens
 * @s: The string to be searched
 * @ct: The characters to search for
 *
 * WARNING: strtok is deprecated, use strsep instead.
 */
char * strtok(char * s,const char * ct)
{
	char *sbegin, *send;

	sbegin  = s ? s : ___strtok;
	if (!sbegin) {
		return NULL;
	}
	sbegin += strspn(sbegin,ct);
	if (*sbegin == '\0') {
		___strtok = NULL;
		return( NULL );
	}
	send = strpbrk( sbegin, ct);
	if (send && *send != '\0')
		*send++ = '\0';
	___strtok = send;
	return (sbegin);
}
#endif

#ifndef __HAVE_ARCH_STRSEP
/**
 * strsep - Split a string into tokens
 * @s: The string to be searched
 * @ct: The characters to search for
 *
 * strsep() updates @s to point after the token, ready for the next call.
 *
 * It returns empty tokens, too, behaving exactly like the libc function
 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
 * Same semantics, slimmer shape. ;)
 */
char * strsep(char **s, const char *ct)
{
	char *sbegin = *s, *end;

	if (sbegin == NULL)
		return NULL;

	end = strpbrk(sbegin, ct);
	if (end)
		*end++ = '\0';
	*s = end;

	return sbegin;
}
#endif

#ifndef __HAVE_ARCH_STRSWAB
/**
 * strswab - swap adjacent even and odd bytes in %NUL-terminated string
 * s: address of the string
 *
 * returns the address of the swapped string or NULL on error. If
 * string length is odd, last byte is untouched.
 */
char *strswab(const char *s)
{
	char *p, *q;

	if ((NULL == s) || ('\0' == *s)) {
		return (NULL);
	}

	for (p=(char *)s, q=p+1; (*p != '\0') && (*q != '\0'); p+=2, q+=2) {
		char  tmp;

		tmp = *p;
		*p  = *q;
		*q  = tmp;
	}

	return (char *) s;
}
#endif

#ifndef __HAVE_ARCH_MEMSET
/**
 * memset - Fill a region of memory with the given value
 * @s: Pointer to the start of the area.
 * @c: The byte to fill the area with
 * @count: The size of the area.
 *
 * Do not use memset() to access IO space, use memset_io() instead.
 */
void * memset(void * s,int c,size_t count)
{
	unsigned long *sl = (unsigned long *) s;
	unsigned long cl = 0;
	char *s8;
	int i;

	/* do it one word at a time (32 bits or 64 bits) while possible */
	if ( ((ulong)s & (sizeof(*sl) - 1)) == 0) {
		for (i = 0; i < sizeof(*sl); i++) {
			cl <<= 8;
			cl |= c & 0xff;
		}
		while (count >= sizeof(*sl)) {
			*sl++ = cl;
			count -= sizeof(*sl);
		}
	}
	/* fill 8 bits at a time */
	s8 = (char *)sl;
	while (count--)
		*s8++ = c;

	return s;
}
#endif

#ifndef __HAVE_ARCH_BCOPY
/**
 * bcopy - Copy one area of memory to another
 * @src: Where to copy from
 * @dest: Where to copy to
 * @count: The size of the area.
 *
 * Note that this is the same as memcpy(), with the arguments reversed.
 * memcpy() is the standard, bcopy() is a legacy BSD function.
 *
 * You should not use this function to access IO space, use memcpy_toio()
 * or memcpy_fromio() instead.
 */
char * bcopy(const char * src, char * dest, int count)
{
	char *tmp = dest;

	while (count--)
		*tmp++ = *src++;

	return dest;
}
#endif

#ifndef __HAVE_ARCH_MEMCPY
/**
 * memcpy - Copy one area of memory to another
 * @dest: Where to copy to
 * @src: Where to copy from
 * @count: The size of the area.
 *
 * You should not use this function to access IO space, use memcpy_toio()
 * or memcpy_fromio() instead.
 */
void * memcpy(void *dest, const void *src, size_t count)
{
	unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src;
	char *d8, *s8;

	/* while all data is aligned (common case), copy a word at a time */
	if ( (((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) {
		while (count >= sizeof(*dl)) {
			*dl++ = *sl++;
			count -= sizeof(*dl);
		}
	}
	/* copy the reset one byte at a time */
	d8 = (char *)dl;
	s8 = (char *)sl;
	while (count--)
		*d8++ = *s8++;

	return dest;
}
#endif

#ifndef __HAVE_ARCH_MEMMOVE
/**
 * memmove - Copy one area of memory to another
 * @dest: Where to copy to
 * @src: Where to copy from
 * @count: The size of the area.
 *
 * Unlike memcpy(), memmove() copes with overlapping areas.
 */
void * memmove(void * dest,const void *src,size_t count)
{
	char *tmp, *s;

	if (dest <= src) {
		tmp = (char *) dest;
		s = (char *) src;
		while (count--)
			*tmp++ = *s++;
		}
	else {
		tmp = (char *) dest + count;
		s = (char *) src + count;
		while (count--)
			*--tmp = *--s;
		}

	return dest;
}
#endif

#ifndef __HAVE_ARCH_MEMCMP
/**
 * memcmp - Compare two areas of memory
 * @cs: One area of memory
 * @ct: Another area of memory
 * @count: The size of the area.
 */
int memcmp(const void * cs,const void * ct,size_t count)
{
	const unsigned char *su1, *su2;
	int res = 0;

	for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
		if ((res = *su1 - *su2) != 0)
			break;
	return res;
}
#endif

#ifndef __HAVE_ARCH_MEMSCAN
/**
 * memscan - Find a character in an area of memory.
 * @addr: The memory area
 * @c: The byte to search for
 * @size: The size of the area.
 *
 * returns the address of the first occurrence of @c, or 1 byte past
 * the area if @c is not found
 */
void * memscan(void * addr, int c, size_t size)
{
	unsigned char * p = (unsigned char *) addr;

	while (size) {
		if (*p == c)
			return (void *) p;
		p++;
		size--;
	}
	return (void *) p;
}
#endif

#ifndef __HAVE_ARCH_STRSTR
/**
 * strstr - Find the first substring in a %NUL terminated string
 * @s1: The string to be searched
 * @s2: The string to search for
 */
char * strstr(const char * s1,const char * s2)
{
	int l1, l2;

	l2 = strlen(s2);
	if (!l2)
		return (char *) s1;
	l1 = strlen(s1);
	while (l1 >= l2) {
		l1--;
		if (!memcmp(s1,s2,l2))
			return (char *) s1;
		s1++;
	}
	return NULL;
}
#endif

#ifndef __HAVE_ARCH_MEMCHR
/**
 * memchr - Find a character in an area of memory.
 * @s: The memory area
 * @c: The byte to search for
 * @n: The size of the area.
 *
 * returns the address of the first occurrence of @c, or %NULL
 * if @c is not found
 */
void *memchr(const void *s, int c, size_t n)
{
	const unsigned char *p = s;
	while (n-- != 0) {
		if ((unsigned char)c == *p++) {
			return (void *)(p-1);
		}
	}
	return NULL;
}

#endif