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/******************************************************************************
* Copyright (c) 2004, 2008 IBM Corporation
* All rights reserved.
* This program and the accompanying materials
* are made available under the terms of the BSD License
* which accompanies this distribution, and is available at
* http://www.opensource.org/licenses/bsd-license.php
*
* Contributors:
* IBM Corporation - initial implementation
*****************************************************************************/
#include <stdlib.h>
unsigned long int strtoul(const char *S, char **PTR,int BASE)
{
unsigned long rval = 0;
short int digit;
// *PTR is S, unless PTR is NULL, in which case i override it with my own ptr
char* ptr;
if (PTR == 0)
{
//override
PTR = &ptr;
}
// i use PTR to advance through the string
*PTR = (char *) S;
//check if BASE is ok
if ((BASE < 0) || BASE > 36)
{
return 0;
}
// ignore white space at beginning of S
while ((**PTR == ' ')
|| (**PTR == '\t')
|| (**PTR == '\n')
|| (**PTR == '\r')
)
{
(*PTR)++;
}
// if BASE is 0... determine the base from the first chars...
if (BASE == 0)
{
// if S starts with "0x", BASE = 16, else 10
if ((**PTR == '0') && (*((*PTR)+1) == 'x'))
{
BASE = 16;
(*PTR)++;
(*PTR)++;
}
else
{
BASE = 10;
}
}
if (BASE == 16)
{
// S may start with "0x"
if ((**PTR == '0') && (*((*PTR)+1) == 'x'))
{
(*PTR)++;
(*PTR)++;
}
}
//until end of string
while (**PTR)
{
if (((**PTR) >= '0') && ((**PTR) <='9'))
{
//digit (0..9)
digit = **PTR - '0';
}
else if (((**PTR) >= 'a') && ((**PTR) <='z'))
{
//alphanumeric digit lowercase(a (10) .. z (35) )
digit = (**PTR - 'a') + 10;
}
else if (((**PTR) >= 'A') && ((**PTR) <='Z'))
{
//alphanumeric digit uppercase(a (10) .. z (35) )
digit = (**PTR - 'A') + 10;
}
else
{
//end of parseable number reached...
break;
}
if (digit < BASE)
{
rval = (rval * BASE) + digit;
}
else
{
//digit found, but its too big for current base
//end of parseable number reached...
break;
}
//next...
(*PTR)++;
}
//done
return rval;
}
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