Root/lib/string.c

Source at commit b386be689295730688885552666ea40b2e639b14 created 8 years 11 months ago.
By Maarten ter Huurne, Revert "MIPS: JZ4740: reset: Initialize hibernate wakeup counters."
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 */
34int 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    if (!len)
40        return 0;
41
42    do {
43        c1 = *s1++;
44        c2 = *s2++;
45        if (!c1 || !c2)
46            break;
47        if (c1 == c2)
48            continue;
49        c1 = tolower(c1);
50        c2 = tolower(c2);
51        if (c1 != c2)
52            break;
53    } while (--len);
54    return (int)c1 - (int)c2;
55}
56EXPORT_SYMBOL(strnicmp);
57#endif
58
59#ifndef __HAVE_ARCH_STRCASECMP
60int strcasecmp(const char *s1, const char *s2)
61{
62    int c1, c2;
63
64    do {
65        c1 = tolower(*s1++);
66        c2 = tolower(*s2++);
67    } while (c1 == c2 && c1 != 0);
68    return c1 - c2;
69}
70EXPORT_SYMBOL(strcasecmp);
71#endif
72
73#ifndef __HAVE_ARCH_STRNCASECMP
74int strncasecmp(const char *s1, const char *s2, size_t n)
75{
76    int c1, c2;
77
78    do {
79        c1 = tolower(*s1++);
80        c2 = tolower(*s2++);
81    } while ((--n > 0) && c1 == c2 && c1 != 0);
82    return c1 - c2;
83}
84EXPORT_SYMBOL(strncasecmp);
85#endif
86
87#ifndef __HAVE_ARCH_STRCPY
88/**
89 * strcpy - Copy a %NUL terminated string
90 * @dest: Where to copy the string to
91 * @src: Where to copy the string from
92 */
93#undef strcpy
94char *strcpy(char *dest, const char *src)
95{
96    char *tmp = dest;
97
98    while ((*dest++ = *src++) != '\0')
99        /* nothing */;
100    return tmp;
101}
102EXPORT_SYMBOL(strcpy);
103#endif
104
105#ifndef __HAVE_ARCH_STRNCPY
106/**
107 * strncpy - Copy a length-limited, %NUL-terminated string
108 * @dest: Where to copy the string to
109 * @src: Where to copy the string from
110 * @count: The maximum number of bytes to copy
111 *
112 * The result is not %NUL-terminated if the source exceeds
113 * @count bytes.
114 *
115 * In the case where the length of @src is less than that of
116 * count, the remainder of @dest will be padded with %NUL.
117 *
118 */
119char *strncpy(char *dest, const char *src, size_t count)
120{
121    char *tmp = dest;
122
123    while (count) {
124        if ((*tmp = *src) != 0)
125            src++;
126        tmp++;
127        count--;
128    }
129    return dest;
130}
131EXPORT_SYMBOL(strncpy);
132#endif
133
134#ifndef __HAVE_ARCH_STRLCPY
135/**
136 * strlcpy - Copy a %NUL terminated string into a sized buffer
137 * @dest: Where to copy the string to
138 * @src: Where to copy the string from
139 * @size: size of destination buffer
140 *
141 * Compatible with *BSD: the result is always a valid
142 * NUL-terminated string that fits in the buffer (unless,
143 * of course, the buffer size is zero). It does not pad
144 * out the result like strncpy() does.
145 */
146size_t strlcpy(char *dest, const char *src, size_t size)
147{
148    size_t ret = strlen(src);
149
150    if (size) {
151        size_t len = (ret >= size) ? size - 1 : ret;
152        memcpy(dest, src, len);
153        dest[len] = '\0';
154    }
155    return ret;
156}
157EXPORT_SYMBOL(strlcpy);
158#endif
159
160#ifndef __HAVE_ARCH_STRCAT
161/**
162 * strcat - Append one %NUL-terminated string to another
163 * @dest: The string to be appended to
164 * @src: The string to append to it
165 */
166#undef strcat
167char *strcat(char *dest, const char *src)
168{
169    char *tmp = dest;
170
171    while (*dest)
172        dest++;
173    while ((*dest++ = *src++) != '\0')
174        ;
175    return tmp;
176}
177EXPORT_SYMBOL(strcat);
178#endif
179
180#ifndef __HAVE_ARCH_STRNCAT
181/**
182 * strncat - Append a length-limited, %NUL-terminated string to another
183 * @dest: The string to be appended to
184 * @src: The string to append to it
185 * @count: The maximum numbers of bytes to copy
186 *
187 * Note that in contrast to strncpy(), strncat() ensures the result is
188 * terminated.
189 */
190char *strncat(char *dest, const char *src, size_t count)
191{
192    char *tmp = dest;
193
194    if (count) {
195        while (*dest)
196            dest++;
197        while ((*dest++ = *src++) != 0) {
198            if (--count == 0) {
199                *dest = '\0';
200                break;
201            }
202        }
203    }
204    return tmp;
205}
206EXPORT_SYMBOL(strncat);
207#endif
208
209#ifndef __HAVE_ARCH_STRLCAT
210/**
211 * strlcat - Append a length-limited, %NUL-terminated string to another
212 * @dest: The string to be appended to
213 * @src: The string to append to it
214 * @count: The size of the destination buffer.
215 */
216size_t strlcat(char *dest, const char *src, size_t count)
217{
218    size_t dsize = strlen(dest);
219    size_t len = strlen(src);
220    size_t res = dsize + len;
221
222    /* This would be a bug */
223    BUG_ON(dsize >= count);
224
225    dest += dsize;
226    count -= dsize;
227    if (len >= count)
228        len = count-1;
229    memcpy(dest, src, len);
230    dest[len] = 0;
231    return res;
232}
233EXPORT_SYMBOL(strlcat);
234#endif
235
236#ifndef __HAVE_ARCH_STRCMP
237/**
238 * strcmp - Compare two strings
239 * @cs: One string
240 * @ct: Another string
241 */
242#undef strcmp
243int strcmp(const char *cs, const char *ct)
244{
245    unsigned char c1, c2;
246
247    while (1) {
248        c1 = *cs++;
249        c2 = *ct++;
250        if (c1 != c2)
251            return c1 < c2 ? -1 : 1;
252        if (!c1)
253            break;
254    }
255    return 0;
256}
257EXPORT_SYMBOL(strcmp);
258#endif
259
260#ifndef __HAVE_ARCH_STRNCMP
261/**
262 * strncmp - Compare two length-limited strings
263 * @cs: One string
264 * @ct: Another string
265 * @count: The maximum number of bytes to compare
266 */
267int strncmp(const char *cs, const char *ct, size_t count)
268{
269    unsigned char c1, c2;
270
271    while (count) {
272        c1 = *cs++;
273        c2 = *ct++;
274        if (c1 != c2)
275            return c1 < c2 ? -1 : 1;
276        if (!c1)
277            break;
278        count--;
279    }
280    return 0;
281}
282EXPORT_SYMBOL(strncmp);
283#endif
284
285#ifndef __HAVE_ARCH_STRCHR
286/**
287 * strchr - Find the first occurrence of a character in a string
288 * @s: The string to be searched
289 * @c: The character to search for
290 */
291char *strchr(const char *s, int c)
292{
293    for (; *s != (char)c; ++s)
294        if (*s == '\0')
295            return NULL;
296    return (char *)s;
297}
298EXPORT_SYMBOL(strchr);
299#endif
300
301#ifndef __HAVE_ARCH_STRRCHR
302/**
303 * strrchr - Find the last occurrence of a character in a string
304 * @s: The string to be searched
305 * @c: The character to search for
306 */
307char *strrchr(const char *s, int c)
308{
309       const char *p = s + strlen(s);
310       do {
311           if (*p == (char)c)
312               return (char *)p;
313       } while (--p >= s);
314       return NULL;
315}
316EXPORT_SYMBOL(strrchr);
317#endif
318
319#ifndef __HAVE_ARCH_STRNCHR
320/**
321 * strnchr - Find a character in a length limited string
322 * @s: The string to be searched
323 * @count: The number of characters to be searched
324 * @c: The character to search for
325 */
326char *strnchr(const char *s, size_t count, int c)
327{
328    for (; count-- && *s != '\0'; ++s)
329        if (*s == (char)c)
330            return (char *)s;
331    return NULL;
332}
333EXPORT_SYMBOL(strnchr);
334#endif
335
336/**
337 * skip_spaces - Removes leading whitespace from @str.
338 * @str: The string to be stripped.
339 *
340 * Returns a pointer to the first non-whitespace character in @str.
341 */
342char *skip_spaces(const char *str)
343{
344    while (isspace(*str))
345        ++str;
346    return (char *)str;
347}
348EXPORT_SYMBOL(skip_spaces);
349
350/**
351 * strim - Removes leading and trailing whitespace from @s.
352 * @s: The string to be stripped.
353 *
354 * Note that the first trailing whitespace is replaced with a %NUL-terminator
355 * in the given string @s. Returns a pointer to the first non-whitespace
356 * character in @s.
357 */
358char *strim(char *s)
359{
360    size_t size;
361    char *end;
362
363    size = strlen(s);
364    if (!size)
365        return s;
366
367    end = s + size - 1;
368    while (end >= s && isspace(*end))
369        end--;
370    *(end + 1) = '\0';
371
372    return skip_spaces(s);
373}
374EXPORT_SYMBOL(strim);
375
376#ifndef __HAVE_ARCH_STRLEN
377/**
378 * strlen - Find the length of a string
379 * @s: The string to be sized
380 */
381size_t strlen(const char *s)
382{
383    const char *sc;
384
385    for (sc = s; *sc != '\0'; ++sc)
386        /* nothing */;
387    return sc - s;
388}
389EXPORT_SYMBOL(strlen);
390#endif
391
392#ifndef __HAVE_ARCH_STRNLEN
393/**
394 * strnlen - Find the length of a length-limited string
395 * @s: The string to be sized
396 * @count: The maximum number of bytes to search
397 */
398size_t strnlen(const char *s, size_t count)
399{
400    const char *sc;
401
402    for (sc = s; count-- && *sc != '\0'; ++sc)
403        /* nothing */;
404    return sc - s;
405}
406EXPORT_SYMBOL(strnlen);
407#endif
408
409#ifndef __HAVE_ARCH_STRSPN
410/**
411 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
412 * @s: The string to be searched
413 * @accept: The string to search for
414 */
415size_t strspn(const char *s, const char *accept)
416{
417    const char *p;
418    const char *a;
419    size_t count = 0;
420
421    for (p = s; *p != '\0'; ++p) {
422        for (a = accept; *a != '\0'; ++a) {
423            if (*p == *a)
424                break;
425        }
426        if (*a == '\0')
427            return count;
428        ++count;
429    }
430    return count;
431}
432
433EXPORT_SYMBOL(strspn);
434#endif
435
436#ifndef __HAVE_ARCH_STRCSPN
437/**
438 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
439 * @s: The string to be searched
440 * @reject: The string to avoid
441 */
442size_t strcspn(const char *s, const char *reject)
443{
444    const char *p;
445    const char *r;
446    size_t count = 0;
447
448    for (p = s; *p != '\0'; ++p) {
449        for (r = reject; *r != '\0'; ++r) {
450            if (*p == *r)
451                return count;
452        }
453        ++count;
454    }
455    return count;
456}
457EXPORT_SYMBOL(strcspn);
458#endif
459
460#ifndef __HAVE_ARCH_STRPBRK
461/**
462 * strpbrk - Find the first occurrence of a set of characters
463 * @cs: The string to be searched
464 * @ct: The characters to search for
465 */
466char *strpbrk(const char *cs, const char *ct)
467{
468    const char *sc1, *sc2;
469
470    for (sc1 = cs; *sc1 != '\0'; ++sc1) {
471        for (sc2 = ct; *sc2 != '\0'; ++sc2) {
472            if (*sc1 == *sc2)
473                return (char *)sc1;
474        }
475    }
476    return NULL;
477}
478EXPORT_SYMBOL(strpbrk);
479#endif
480
481#ifndef __HAVE_ARCH_STRSEP
482/**
483 * strsep - Split a string into tokens
484 * @s: The string to be searched
485 * @ct: The characters to search for
486 *
487 * strsep() updates @s to point after the token, ready for the next call.
488 *
489 * It returns empty tokens, too, behaving exactly like the libc function
490 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
491 * Same semantics, slimmer shape. ;)
492 */
493char *strsep(char **s, const char *ct)
494{
495    char *sbegin = *s;
496    char *end;
497
498    if (sbegin == NULL)
499        return NULL;
500
501    end = strpbrk(sbegin, ct);
502    if (end)
503        *end++ = '\0';
504    *s = end;
505    return sbegin;
506}
507EXPORT_SYMBOL(strsep);
508#endif
509
510/**
511 * sysfs_streq - return true if strings are equal, modulo trailing newline
512 * @s1: one string
513 * @s2: another string
514 *
515 * This routine returns true iff two strings are equal, treating both
516 * NUL and newline-then-NUL as equivalent string terminations. It's
517 * geared for use with sysfs input strings, which generally terminate
518 * with newlines but are compared against values without newlines.
519 */
520bool sysfs_streq(const char *s1, const char *s2)
521{
522    while (*s1 && *s1 == *s2) {
523        s1++;
524        s2++;
525    }
526
527    if (*s1 == *s2)
528        return true;
529    if (!*s1 && *s2 == '\n' && !s2[1])
530        return true;
531    if (*s1 == '\n' && !s1[1] && !*s2)
532        return true;
533    return false;
534}
535EXPORT_SYMBOL(sysfs_streq);
536
537/**
538 * strtobool - convert common user inputs into boolean values
539 * @s: input string
540 * @res: result
541 *
542 * This routine returns 0 iff the first character is one of 'Yy1Nn0'.
543 * Otherwise it will return -EINVAL. Value pointed to by res is
544 * updated upon finding a match.
545 */
546int strtobool(const char *s, bool *res)
547{
548    switch (s[0]) {
549    case 'y':
550    case 'Y':
551    case '1':
552        *res = true;
553        break;
554    case 'n':
555    case 'N':
556    case '0':
557        *res = false;
558        break;
559    default:
560        return -EINVAL;
561    }
562    return 0;
563}
564EXPORT_SYMBOL(strtobool);
565
566#ifndef __HAVE_ARCH_MEMSET
567/**
568 * memset - Fill a region of memory with the given value
569 * @s: Pointer to the start of the area.
570 * @c: The byte to fill the area with
571 * @count: The size of the area.
572 *
573 * Do not use memset() to access IO space, use memset_io() instead.
574 */
575void *memset(void *s, int c, size_t count)
576{
577    char *xs = s;
578
579    while (count--)
580        *xs++ = c;
581    return s;
582}
583EXPORT_SYMBOL(memset);
584#endif
585
586#ifndef __HAVE_ARCH_MEMCPY
587/**
588 * memcpy - Copy one area of memory to another
589 * @dest: Where to copy to
590 * @src: Where to copy from
591 * @count: The size of the area.
592 *
593 * You should not use this function to access IO space, use memcpy_toio()
594 * or memcpy_fromio() instead.
595 */
596void *memcpy(void *dest, const void *src, size_t count)
597{
598    char *tmp = dest;
599    const char *s = src;
600
601    while (count--)
602        *tmp++ = *s++;
603    return dest;
604}
605EXPORT_SYMBOL(memcpy);
606#endif
607
608#ifndef __HAVE_ARCH_MEMMOVE
609/**
610 * memmove - Copy one area of memory to another
611 * @dest: Where to copy to
612 * @src: Where to copy from
613 * @count: The size of the area.
614 *
615 * Unlike memcpy(), memmove() copes with overlapping areas.
616 */
617void *memmove(void *dest, const void *src, size_t count)
618{
619    char *tmp;
620    const char *s;
621
622    if (dest <= src) {
623        tmp = dest;
624        s = src;
625        while (count--)
626            *tmp++ = *s++;
627    } else {
628        tmp = dest;
629        tmp += count;
630        s = src;
631        s += count;
632        while (count--)
633            *--tmp = *--s;
634    }
635    return dest;
636}
637EXPORT_SYMBOL(memmove);
638#endif
639
640#ifndef __HAVE_ARCH_MEMCMP
641/**
642 * memcmp - Compare two areas of memory
643 * @cs: One area of memory
644 * @ct: Another area of memory
645 * @count: The size of the area.
646 */
647#undef memcmp
648int memcmp(const void *cs, const void *ct, size_t count)
649{
650    const unsigned char *su1, *su2;
651    int res = 0;
652
653    for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
654        if ((res = *su1 - *su2) != 0)
655            break;
656    return res;
657}
658EXPORT_SYMBOL(memcmp);
659#endif
660
661#ifndef __HAVE_ARCH_MEMSCAN
662/**
663 * memscan - Find a character in an area of memory.
664 * @addr: The memory area
665 * @c: The byte to search for
666 * @size: The size of the area.
667 *
668 * returns the address of the first occurrence of @c, or 1 byte past
669 * the area if @c is not found
670 */
671void *memscan(void *addr, int c, size_t size)
672{
673    unsigned char *p = addr;
674
675    while (size) {
676        if (*p == c)
677            return (void *)p;
678        p++;
679        size--;
680    }
681      return (void *)p;
682}
683EXPORT_SYMBOL(memscan);
684#endif
685
686#ifndef __HAVE_ARCH_STRSTR
687/**
688 * strstr - Find the first substring in a %NUL terminated string
689 * @s1: The string to be searched
690 * @s2: The string to search for
691 */
692char *strstr(const char *s1, const char *s2)
693{
694    size_t l1, l2;
695
696    l2 = strlen(s2);
697    if (!l2)
698        return (char *)s1;
699    l1 = strlen(s1);
700    while (l1 >= l2) {
701        l1--;
702        if (!memcmp(s1, s2, l2))
703            return (char *)s1;
704        s1++;
705    }
706    return NULL;
707}
708EXPORT_SYMBOL(strstr);
709#endif
710
711#ifndef __HAVE_ARCH_STRNSTR
712/**
713 * strnstr - Find the first substring in a length-limited string
714 * @s1: The string to be searched
715 * @s2: The string to search for
716 * @len: the maximum number of characters to search
717 */
718char *strnstr(const char *s1, const char *s2, size_t len)
719{
720    size_t l2;
721
722    l2 = strlen(s2);
723    if (!l2)
724        return (char *)s1;
725    while (len >= l2) {
726        len--;
727        if (!memcmp(s1, s2, l2))
728            return (char *)s1;
729        s1++;
730    }
731    return NULL;
732}
733EXPORT_SYMBOL(strnstr);
734#endif
735
736#ifndef __HAVE_ARCH_MEMCHR
737/**
738 * memchr - Find a character in an area of memory.
739 * @s: The memory area
740 * @c: The byte to search for
741 * @n: The size of the area.
742 *
743 * returns the address of the first occurrence of @c, or %NULL
744 * if @c is not found
745 */
746void *memchr(const void *s, int c, size_t n)
747{
748    const unsigned char *p = s;
749    while (n-- != 0) {
750            if ((unsigned char)c == *p++) {
751            return (void *)(p - 1);
752        }
753    }
754    return NULL;
755}
756EXPORT_SYMBOL(memchr);
757#endif
758
759static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
760{
761    while (bytes) {
762        if (*start != value)
763            return (void *)start;
764        start++;
765        bytes--;
766    }
767    return NULL;
768}
769
770/**
771 * memchr_inv - Find an unmatching character in an area of memory.
772 * @start: The memory area
773 * @c: Find a character other than c
774 * @bytes: The size of the area.
775 *
776 * returns the address of the first character other than @c, or %NULL
777 * if the whole buffer contains just @c.
778 */
779void *memchr_inv(const void *start, int c, size_t bytes)
780{
781    u8 value = c;
782    u64 value64;
783    unsigned int words, prefix;
784
785    if (bytes <= 16)
786        return check_bytes8(start, value, bytes);
787
788    value64 = value | value << 8 | value << 16 | value << 24;
789    value64 = (value64 & 0xffffffff) | value64 << 32;
790    prefix = 8 - ((unsigned long)start) % 8;
791
792    if (prefix) {
793        u8 *r = check_bytes8(start, value, prefix);
794        if (r)
795            return r;
796        start += prefix;
797        bytes -= prefix;
798    }
799
800    words = bytes / 8;
801
802    while (words) {
803        if (*(u64 *)start != value64)
804            return check_bytes8(start, value, 8);
805        start += 8;
806        words--;
807    }
808
809    return check_bytes8(start, value, bytes % 8);
810}
811EXPORT_SYMBOL(memchr_inv);
812

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