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/*

 * Copyright (c) 2005 Martin Decky

 * Copyright (c) 2008 Jiri Svoboda

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup libc

 * @{

 */

/** @file

 */

#include <string.h>

#include <stdlib.h>

#include <limits.h>

#include <ctype.h>

#include <malloc.h>

/** Count the number of characters in the string, not including terminating 0.

 *

 * @param str		String.

 * @return		Number of characters in string.

 */

size_t strlen(const char *str) 

{

	size_t counter = 0;

	while (str[counter] != 0)

		counter++;

	return counter;

}

int strcmp(const char *a, const char *b)

{

	int c = 0;

	while (a[c] && b[c] && (!(a[c] - b[c])))

		c++;

	return (a[c] - b[c]);

}

int strncmp(const char *a, const char *b, size_t n)

{

	size_t c = 0;

	while (c < n && a[c] && b[c] && (!(a[c] - b[c])))

		c++;

	return ( c < n ? a[c] - b[c] : 0);

}

int stricmp(const char *a, const char *b)

{

	int c = 0;

	while (a[c] && b[c] && (!(tolower(a[c]) - tolower(b[c]))))

		c++;

	return (tolower(a[c]) - tolower(b[c]));

}

/** Return pointer to the first occurence of character c in string.

 *

 * @param str		Scanned string.

 * @param c		Searched character (taken as one byte).

 * @return		Pointer to the matched character or NULL if it is not

 * 			found in given string.

 */

char *strchr(const char *str, int c)

{

	while (*str != '\0') {

		if (*str == (char) c)

			return (char *) str;

		str++;

	}

	return NULL;

}

/** Return pointer to the last occurence of character c in string.

 *

 * @param str		Scanned string.

 * @param c		Searched character (taken as one byte).

 * @return		Pointer to the matched character or NULL if it is not

 * 			found in given string.

 */

char *strrchr(const char *str, int c)

{

	char *retval = NULL;

	while (*str != '\0') {

		if (*str == (char) c)

			retval = (char *) str;

		str++;

	}

	return (char *) retval;

}

/** Convert string to a number. 

 * Core of strtol and strtoul functions.

 *

 * @param nptr		Pointer to string.

 * @param endptr	If not NULL, function stores here pointer to the first

 * 			invalid character.

 * @param base		Zero or number between 2 and 36 inclusive.

 * @param sgn		It's set to 1 if minus found.

 * @return		Result of conversion.

 */

static unsigned long

_strtoul(const char *nptr, char **endptr, int base, char *sgn)

{

	unsigned char c;

	unsigned long result = 0;

	unsigned long a, b;

	const char *str = nptr;

	const char *tmpptr;

	while (isspace(*str))

		str++;

	if (*str == '-') {

		*sgn = 1;

		++str;

	} else if (*str == '+')

		++str;

	if (base) {

		if ((base == 1) || (base > 36)) {

			/* FIXME: set errno to EINVAL */

			return 0;

		}

		if ((base == 16) && (*str == '0') && ((str[1] == 'x') ||

		    (str[1] == 'X'))) {

			str += 2;

		}

	} else {

		base = 10;

		if (*str == '0') {

			base = 8;

			if ((str[1] == 'X') || (str[1] == 'x'))  {

				base = 16;

				str += 2;

			}

		} 

	}

	tmpptr = str;

	while (*str) {

		c = *str;

		c = (c >= 'a' ? c - 'a' + 10 : (c >= 'A' ? c - 'A' + 10 :

		    (c <= '9' ? c - '0' : 0xff)));

		if (c > base) {

			break;

		}

		a = (result & 0xff) * base + c;

		b = (result >> 8) * base + (a >> 8);

		if (b > (ULONG_MAX >> 8)) {

			/* overflow */

			/* FIXME: errno = ERANGE*/

			return ULONG_MAX;

		}

		result = (b << 8) + (a & 0xff);

		++str;

	}

	if (str == tmpptr) {

		/*

		 * No number was found => first invalid character is the first

		 * character of the string.

		 */

		/* FIXME: set errno to EINVAL */

		str = nptr;

		result = 0;

	}

	if (endptr)

		*endptr = (char *) str;

	if (nptr == str) { 

		/*FIXME: errno = EINVAL*/

		return 0;

	}

	return result;

}

/** Convert initial part of string to long int according to given base.

 * The number may begin with an arbitrary number of whitespaces followed by

 * optional sign (`+' or `-'). If the base is 0 or 16, the prefix `0x' may be

 * inserted and the number will be taken as hexadecimal one. If the base is 0

 * and the number begin with a zero, number will be taken as octal one (as with

 * base 8). Otherwise the base 0 is taken as decimal.

 *

 * @param nptr		Pointer to string.

 * @param endptr	If not NULL, function stores here pointer to the first

 * 			invalid character.

 * @param base		Zero or number between 2 and 36 inclusive.

 * @return		Result of conversion.

 */

long int strtol(const char *nptr, char **endptr, int base)

{

	char sgn = 0;

	unsigned long number = 0;

	number = _strtoul(nptr, endptr, base, &sgn);

	if (number > LONG_MAX) {

		if ((sgn) && (number == (unsigned long) (LONG_MAX) + 1)) {

			/* FIXME: set 0 to errno */

			return number;		

		}

		/* FIXME: set ERANGE to errno */

		return (sgn ? LONG_MIN : LONG_MAX);	

	}

	return (sgn ? -number : number);

}

/** Convert initial part of string to unsigned long according to given base.

 * The number may begin with an arbitrary number of whitespaces followed by

 * optional sign (`+' or `-'). If the base is 0 or 16, the prefix `0x' may be

 * inserted and the number will be taken as hexadecimal one. If the base is 0

 * and the number begin with a zero, number will be taken as octal one (as with

 * base 8). Otherwise the base 0 is taken as decimal.

 *

 * @param nptr		Pointer to string.

 * @param endptr	If not NULL, function stores here pointer to the first

 * 			invalid character

 * @param base		Zero or number between 2 and 36 inclusive.

 * @return		Result of conversion.

 */

unsigned long strtoul(const char *nptr, char **endptr, int base)

{

	char sgn = 0;

	unsigned long number = 0;

	number = _strtoul(nptr, endptr, base, &sgn);

	return (sgn ? -number : number);

}

char *strcpy(char *dest, const char *src)

{

	char *orig = dest;

	while ((*(dest++) = *(src++)))

		;

	return orig;

}

char *strncpy(char *dest, const char *src, size_t n)

{

	char *orig = dest;

	while ((*(dest++) = *(src++)) && --n)

		;

	return orig;

}

char *strcat(char *dest, const char *src)

{

	char *orig = dest;

	while (*dest++)

		;

	--dest;

	while ((*dest++ = *src++))

		;

	return orig;

}

char * strdup(const char *s1)

{

	size_t len = strlen(s1) + 1;

	void *ret = malloc(len);

	if (ret == NULL)

		return (char *) NULL;

	return (char *) memcpy(ret, s1, len);

}

char *strtok(char *s, const char *delim)

{

	static char *next;

	return strtok_r(s, delim, &next);

}

char *strtok_r(char *s, const char *delim, char **next)

{

	char *start, *end;

	if (s == NULL)

		s = *next;

	/* Skip over leading delimiters. */

	while (*s && (strchr(delim, *s) != NULL)) ++s;

	start = s;

	/* Skip over token characters. */

	while (*s && (strchr(delim, *s) == NULL)) ++s;

	end = s;

	*next = (*s ? s + 1 : s);

	if (start == end) {

		return NULL;	/* No more tokens. */

	}

	/* Overwrite delimiter with NULL terminator. */

	*end = '\0';

	return start;

}

/** @}

 */