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999 palkovsky 1
/*
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 * Copyright (C) 2005 Martin Decky
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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#include <string.h>
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#include <unistd.h>
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#include <ctype.h>
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#include <limits.h>
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/* Dummy implementation of mem/ functions */
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void * memset(void *s, int c, size_t n)
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{
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    char *os = s;
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    while (n--)
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        *(os++) = c;
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    return s;
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}
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void * memcpy(void *dest, void *src, size_t n)
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{
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    char *os = src;
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    char *odst = dest;
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    while (n--)
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        *(odst++) = *(os++);
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    return dest;
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}
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/** Count the number of characters in the string, not including terminating 0.
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 * @param str string
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 * @return number of characters in string.
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 */
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size_t strlen(const char *str)
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{
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    size_t counter = 0;
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    while (str[counter] != 0) {
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        counter++;
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    }
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    return counter;
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}
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int strcmp(const char *a,const char *b)
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{
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    int c=0;
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    while(a[c]&&b[c]&&(!(a[c]-b[c]))) c++;
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    return a[c]-b[c];
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}
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/** Return pointer to the first occurence of character c in string
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 * @param str scanned string
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 * @param c searched character (taken as one byte)
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 * @return pointer to the matched character or NULL if it is not found in given string.
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 */
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char *strchr(const char *str, int c)
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{
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    while (*str != '\0') {
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        if (*str == (char)c)
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            return (char *)str;
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        str++;
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    }
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    return NULL;
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}
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/** Return pointer to the last occurence of character c in string
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 * @param str scanned string
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 * @param c searched character (taken as one byte)
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 * @return pointer to the matched character or NULL if it is not found in given string.
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 */
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char *strrchr(const char *str, int c)
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{
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    char *retval = NULL;
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    while (*str != '\0') {
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        if (*str == (char)c)
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            retval = (char *)str;
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        str++;
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    }
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    return (char *)retval;
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}
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/** Convert string to a number.
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 * Core of strtol and strtoul functions.
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 * @param nptr pointer to string
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 * @param endptr if not NULL, function stores here pointer to the first invalid character
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 * @param base zero or number between 2 and 36 inclusive
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 * @param sgn its set to 1 if minus found
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 * @return result of conversion.
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 */
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static unsigned long _strtoul(const char *nptr, char **endptr, int base, char *sgn)
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{
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    unsigned char c;
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    unsigned long result = 0;
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    unsigned long a, b;
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    const char *str = nptr;
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    const char *tmpptr;
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    while (isspace(*str))
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        str++;
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    if (*str == '-') {
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        *sgn = 1;
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        ++str;
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    } else if (*str == '+')
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        ++str;
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    if (base) {
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        if ((base == 1) || (base > 36)) {
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            /* FIXME: set errno to EINVAL */
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            return 0;
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        }
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        if ((base == 16) && (*str == '0') && ((str[1] == 'x') || (str[1] == 'X'))) {
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            str += 2;
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        }
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    } else {
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        base = 10;
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        if (*str == '0') {
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            base = 8;
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            if ((str[1] == 'X') || (str[1] == 'x'))  {
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                base = 16;
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                str += 2;
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            }
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        }
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    }
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    tmpptr = str;
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    while (*str) {
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        c = *str;
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        c = ( c >= 'a'? c-'a'+10:(c >= 'A'?c-'A'+10:(c <= '9'?c-'0':0xff)));
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        if (c > base) {
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            break;
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        }
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        a = (result & 0xff) * base + c;
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        b = (result >> 8) * base + (a >> 8);
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        if (b > (ULONG_MAX >> 8)) {
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            /* overflow */
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            /* FIXME: errno = ERANGE*/
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            return ULONG_MAX;
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        }
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        result = (b << 8) + (a & 0xff);
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        ++str;
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    }
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    if (str == tmpptr) {
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        /* no number was found => first invalid character is the first character of the string */
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        /* FIXME: set errno to EINVAL */
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        str = nptr;
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        result = 0;
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    }
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    if (endptr)
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        *endptr = (char *)str;
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    if (nptr == str) {
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        /*FIXME: errno = EINVAL*/
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        return 0;
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    }
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    return result;
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}
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/** Convert initial part of string to long int according to given base.
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 * The number may begin with an arbitrary number of whitespaces followed by optional sign (`+' or `-').
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 * If the base is 0 or 16, the prefix `0x' may be inserted and the number will be taken as hexadecimal one.
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 * If the base is 0 and the number begin with a zero, number will be taken as octal one (as with base 8).
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 * Otherwise the base 0 is taken as decimal.
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 * @param nptr pointer to string
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 * @param endptr if not NULL, function stores here pointer to the first invalid character
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 * @param base zero or number between 2 and 36 inclusive
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 * @return result of conversion.
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 */
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long int strtol(const char *nptr, char **endptr, int base)
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{
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    char sgn = 0;
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    unsigned long number = 0;
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    number = _strtoul(nptr, endptr, base, &sgn);
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    if (number > LONG_MAX) {
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        if ((sgn) && (number == (unsigned long)(LONG_MAX) + 1)) {
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            /* FIXME: set 0 to errno */
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            return number;     
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        }
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        /* FIXME: set ERANGE to errno */
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        return (sgn?LONG_MIN:LONG_MAX);
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    }
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    return (sgn?-number:number);
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}
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/** Convert initial part of string to unsigned long according to given base.
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 * The number may begin with an arbitrary number of whitespaces followed by optional sign (`+' or `-').
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 * If the base is 0 or 16, the prefix `0x' may be inserted and the number will be taken as hexadecimal one.
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 * If the base is 0 and the number begin with a zero, number will be taken as octal one (as with base 8).
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 * Otherwise the base 0 is taken as decimal.
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 * @param nptr pointer to string
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 * @param endptr if not NULL, function stores here pointer to the first invalid character
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 * @param base zero or number between 2 and 36 inclusive
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 * @return result of conversion.
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 */
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unsigned long strtoul(const char *nptr, char **endptr, int base)
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{
242
    char sgn = 0;
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    unsigned long number = 0;
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    number = _strtoul(nptr, endptr, base, &sgn);
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    return (sgn?-number:number);
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}