/*
 *  linux/lib/string.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */


#include <linux/types.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/bug.h>
#include <linux/errno.h>

#ifndef __HAVE_ARCH_STRNICMP
int strnicmp(const char *s1, const char *s2, size_t len)
{
	
	unsigned char c1, c2;

	if (!len)
		return 0;

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

#ifndef __HAVE_ARCH_STRCASECMP
int strcasecmp(const char *s1, const char *s2)
{
	int c1, c2;

	do {
		c1 = tolower(*s1++);
		c2 = tolower(*s2++);
	} while (c1 == c2 && c1 != 0);
	return c1 - c2;
}
EXPORT_SYMBOL(strcasecmp);
#endif

#ifndef __HAVE_ARCH_STRNCASECMP
int strncasecmp(const char *s1, const char *s2, size_t n)
{
	int c1, c2;

	do {
		c1 = tolower(*s1++);
		c2 = tolower(*s2++);
	} while ((--n > 0) && c1 == c2 && c1 != 0);
	return c1 - c2;
}
EXPORT_SYMBOL(strncasecmp);
#endif

#ifndef __HAVE_ARCH_STRCPY
#undef strcpy
char *strcpy(char *dest, const char *src)
{
	char *tmp = dest;

	while ((*dest++ = *src++) != '\0')
		;
	return tmp;
}
EXPORT_SYMBOL(strcpy);
#endif

#ifndef __HAVE_ARCH_STRNCPY
char *strncpy(char *dest, const char *src, size_t count)
{
	char *tmp = dest;

	while (count) {
		if ((*tmp = *src) != 0)
			src++;
		tmp++;
		count--;
	}
	return dest;
}
EXPORT_SYMBOL(strncpy);
#endif

#ifndef __HAVE_ARCH_STRLCPY
size_t strlcpy(char *dest, const char *src, size_t size)
{
	size_t ret = strlen(src);

	if (size) {
		size_t len = (ret >= size) ? size - 1 : ret;
		memcpy(dest, src, len);
		dest[len] = '\0';
	}
	return ret;
}
EXPORT_SYMBOL(strlcpy);
#endif

#ifndef __HAVE_ARCH_STRCAT
#undef strcat
char *strcat(char *dest, const char *src)
{
	char *tmp = dest;

	while (*dest)
		dest++;
	while ((*dest++ = *src++) != '\0')
		;
	return tmp;
}
EXPORT_SYMBOL(strcat);
#endif

#ifndef __HAVE_ARCH_STRNCAT
char *strncat(char *dest, const char *src, size_t count)
{
	char *tmp = dest;

	if (count) {
		while (*dest)
			dest++;
		while ((*dest++ = *src++) != 0) {
			if (--count == 0) {
				*dest = '\0';
				break;
			}
		}
	}
	return tmp;
}
EXPORT_SYMBOL(strncat);
#endif

#ifndef __HAVE_ARCH_STRLCAT
size_t strlcat(char *dest, const char *src, size_t count)
{
	size_t dsize = strlen(dest);
	size_t len = strlen(src);
	size_t res = dsize + len;

	
	BUG_ON(dsize >= count);

	dest += dsize;
	count -= dsize;
	if (len >= count)
		len = count-1;
	memcpy(dest, src, len);
	dest[len] = 0;
	return res;
}
EXPORT_SYMBOL(strlcat);
#endif

#ifndef __HAVE_ARCH_STRCMP
#undef strcmp
int strcmp(const char *cs, const char *ct)
{
	unsigned char c1, c2;

	while (1) {
		c1 = *cs++;
		c2 = *ct++;
		if (c1 != c2)
			return c1 < c2 ? -1 : 1;
		if (!c1)
			break;
	}
	return 0;
}
EXPORT_SYMBOL(strcmp);
#endif

#ifndef __HAVE_ARCH_STRNCMP
int strncmp(const char *cs, const char *ct, size_t count)
{
	unsigned char c1, c2;

	while (count) {
		c1 = *cs++;
		c2 = *ct++;
		if (c1 != c2)
			return c1 < c2 ? -1 : 1;
		if (!c1)
			break;
		count--;
	}
	return 0;
}
EXPORT_SYMBOL(strncmp);
#endif

#ifndef __HAVE_ARCH_STRCHR
char *strchr(const char *s, int c)
{
	for (; *s != (char)c; ++s)
		if (*s == '\0')
			return NULL;
	return (char *)s;
}
EXPORT_SYMBOL(strchr);
#endif

#ifndef __HAVE_ARCH_STRRCHR
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;
}
EXPORT_SYMBOL(strrchr);
#endif

#ifndef __HAVE_ARCH_STRNCHR
char *strnchr(const char *s, size_t count, int c)
{
	for (; count-- && *s != '\0'; ++s)
		if (*s == (char)c)
			return (char *)s;
	return NULL;
}
EXPORT_SYMBOL(strnchr);
#endif

char *skip_spaces(const char *str)
{
	while (isspace(*str))
		++str;
	return (char *)str;
}
EXPORT_SYMBOL(skip_spaces);

char *strim(char *s)
{
	size_t size;
	char *end;

	size = strlen(s);
	if (!size)
		return s;

	end = s + size - 1;
	while (end >= s && isspace(*end))
		end--;
	*(end + 1) = '\0';

	return skip_spaces(s);
}
EXPORT_SYMBOL(strim);

#ifndef __HAVE_ARCH_STRLEN
size_t strlen(const char *s)
{
	const char *sc;

	for (sc = s; *sc != '\0'; ++sc)
		;
	return sc - s;
}
EXPORT_SYMBOL(strlen);
#endif

#ifndef __HAVE_ARCH_STRNLEN
size_t strnlen(const char *s, size_t count)
{
	const char *sc;

	for (sc = s; count-- && *sc != '\0'; ++sc)
		;
	return sc - s;
}
EXPORT_SYMBOL(strnlen);
#endif

#ifndef __HAVE_ARCH_STRSPN
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;
}

EXPORT_SYMBOL(strspn);
#endif

#ifndef __HAVE_ARCH_STRCSPN
size_t strcspn(const char *s, const char *reject)
{
	const char *p;
	const char *r;
	size_t count = 0;

	for (p = s; *p != '\0'; ++p) {
		for (r = reject; *r != '\0'; ++r) {
			if (*p == *r)
				return count;
		}
		++count;
	}
	return count;
}
EXPORT_SYMBOL(strcspn);
#endif

#ifndef __HAVE_ARCH_STRPBRK
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;
}
EXPORT_SYMBOL(strpbrk);
#endif

#ifndef __HAVE_ARCH_STRSEP
char *strsep(char **s, const char *ct)
{
	char *sbegin = *s;
	char *end;

	if (sbegin == NULL)
		return NULL;

	end = strpbrk(sbegin, ct);
	if (end)
		*end++ = '\0';
	*s = end;
	return sbegin;
}
EXPORT_SYMBOL(strsep);
#endif

bool sysfs_streq(const char *s1, const char *s2)
{
	while (*s1 && *s1 == *s2) {
		s1++;
		s2++;
	}

	if (*s1 == *s2)
		return true;
	if (!*s1 && *s2 == '\n' && !s2[1])
		return true;
	if (*s1 == '\n' && !s1[1] && !*s2)
		return true;
	return false;
}
EXPORT_SYMBOL(sysfs_streq);

int strtobool(const char *s, bool *res)
{
	switch (s[0]) {
	case 'y':
	case 'Y':
	case '1':
		*res = true;
		break;
	case 'n':
	case 'N':
	case '0':
		*res = false;
		break;
	default:
		return -EINVAL;
	}
	return 0;
}
EXPORT_SYMBOL(strtobool);

#ifndef __HAVE_ARCH_MEMSET
void *memset(void *s, int c, size_t count)
{
	char *xs = s;

	while (count--)
		*xs++ = c;
	return s;
}
EXPORT_SYMBOL(memset);
#endif

#ifndef __HAVE_ARCH_MEMCPY
void *memcpy(void *dest, const void *src, size_t count)
{
	char *tmp = dest;
	const char *s = src;

	while (count--)
		*tmp++ = *s++;
	return dest;
}
EXPORT_SYMBOL(memcpy);
#endif

#ifndef __HAVE_ARCH_MEMMOVE
void *memmove(void *dest, const void *src, size_t count)
{
	char *tmp;
	const char *s;

	if (dest <= src) {
		tmp = dest;
		s = src;
		while (count--)
			*tmp++ = *s++;
	} else {
		tmp = dest;
		tmp += count;
		s = src;
		s += count;
		while (count--)
			*--tmp = *--s;
	}
	return dest;
}
EXPORT_SYMBOL(memmove);
#endif

#ifndef __HAVE_ARCH_MEMCMP
#undef memcmp
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;
}
EXPORT_SYMBOL(memcmp);
#endif

#ifndef __HAVE_ARCH_MEMSCAN
void *memscan(void *addr, int c, size_t size)
{
	unsigned char *p = addr;

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

#ifndef __HAVE_ARCH_STRSTR
char *strstr(const char *s1, const char *s2)
{
	size_t 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;
}
EXPORT_SYMBOL(strstr);
#endif

#ifndef __HAVE_ARCH_STRNSTR
char *strnstr(const char *s1, const char *s2, size_t len)
{
	size_t l2;

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

#ifndef __HAVE_ARCH_MEMCHR
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;
}
EXPORT_SYMBOL(memchr);
#endif

static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
{
	while (bytes) {
		if (*start != value)
			return (void *)start;
		start++;
		bytes--;
	}
	return NULL;
}

void *memchr_inv(const void *start, int c, size_t bytes)
{
	u8 value = c;
	u64 value64;
	unsigned int words, prefix;

	if (bytes <= 16)
		return check_bytes8(start, value, bytes);

	value64 = value;
#if defined(ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64
	value64 *= 0x0101010101010101;
#elif defined(ARCH_HAS_FAST_MULTIPLIER)
	value64 *= 0x01010101;
	value64 |= value64 << 32;
#else
	value64 |= value64 << 8;
	value64 |= value64 << 16;
	value64 |= value64 << 32;
#endif

	prefix = (unsigned long)start % 8;
	if (prefix) {
		u8 *r;

		prefix = 8 - prefix;
		r = check_bytes8(start, value, prefix);
		if (r)
			return r;
		start += prefix;
		bytes -= prefix;
	}

	words = bytes / 8;

	while (words) {
		if (*(u64 *)start != value64)
			return check_bytes8(start, value, 8);
		start += 8;
		words--;
	}

	return check_bytes8(start, value, bytes % 8);
}
EXPORT_SYMBOL(memchr_inv);