Viewing file:  strtoul.c (2.33 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/* ========================================================================
* Copyright 1988-2006 University of Washington
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
*
* ========================================================================
*/
/*
* Program: String to unsigned long
*
* Author: Mark Crispin
* Networks and Distributed Computing
* Computing & Communications
* University of Washington
* Administration Building, AG-44
* Seattle, WA 98195
*
* Date: 14 February 1995
* Last Edited: 30 August 2006
*/
/*
* Turn a string unsigned long into the real thing
* Accepts: source string
* pointer to place to return end pointer
* base
* Returns: parsed unsigned long integer, end pointer is updated
*/
unsigned long strtoul (char *t,char **endp,int base)
{
unsigned long value = 0; /* the accumulated value */
int negative = 0; /* this a negative number? */
unsigned char c,*s = t;
if (base && (base < 2 || base > 36)) {
errno = EINVAL; /* insist upon valid base */
return value;
}
while (isspace (*s)) s++; /* skip leading whitespace */
switch (*s) { /* check for leading sign char */
case '-':
negative = 1; /* yes, negative #. fall into '+' */
case '+':
s++; /* skip the sign character */
}
if (!base) { /* base not specified? */
if (*s != '0') base = 10; /* must be decimal if doesn't start with 0 */
/* starts with 0x? */
else if (tolower (*++s) == 'x') {
base = 16; /* yes, is hex */
s++; /* skip the x */
}
else base = 8; /* ...or octal */
}
do { /* convert to numeric form if digit */
if (isdigit (*s)) c = *s - '0';
/* alphabetic conversion */
else if (isalpha (*s)) c = *s - (isupper (*s) ? 'A' : 'a') + 10;
else break; /* else no way it's valid */
if (c >= base) break; /* digit out of range for base? */
value = value * base + c; /* accumulate the digit */
} while (*++s); /* loop until non-numeric character */
if (tolower (*s) == 'l') s++; /* ignore 'l' or 'L' marker */
if (endp) *endp = s; /* save users endp to after number */
/* negate number if needed */
return negative ? -value : value;
}
|