adtools/clib2

/*
 * $Id: stdlib_strtoul.c,v 1.6 2006-01-08 12:04:26 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2015 by Olaf Barthel <obarthel (at) gmx.net>
 * 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.
 *
 *   - Neither the name of Olaf Barthel nor the names of contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
 */

#ifndef _STDLIB_NULL_POINTER_CHECK_H
#include "stdlib_null_pointer_check.h"
#endif /* _STDLIB_NULL_POINTER_CHECK_H */

/****************************************************************************/

#ifndef _STDLIB_HEADERS_H
#include "stdlib_headers.h"
#endif /* _STDLIB_HEADERS_H */

/****************************************************************************/

unsigned long
strtoul(const char *str, char **ptr, int base)
{
    const char * stop = str;
    size_t num_digits_converted = 0;
    BOOL is_negative;
    unsigned long result = 0;
    unsigned long new_sum;
    unsigned long sum;
    char c;

    ENTER();

    SHOWSTRING(str);
    SHOWPOINTER(ptr);
    SHOWVALUE(base);

    assert(str != NULL && base >= 0);

    #if defined(CHECK_FOR_NULL_POINTERS)
    {
        if(str == NULL)
        {
            SHOWMSG("invalid str parameter");

            __set_errno(EFAULT);
            goto out;
        }
    }
    #endif /* CHECK_FOR_NULL_POINTERS */

    if(base < 0)
    {
        SHOWMSG("invalid base parameter");

        __set_errno(ERANGE);
        goto out;
    }

    /* Skip all leading blanks. */
    while((c = (*str)) != '\0')
    {
        if(NOT isspace(c))
            break;

        str++;
    }

    /* The first character may be a sign. */
    if(c == '-')
    {
        /* It's a negative number. */
        is_negative = TRUE;

        str++;
    }
    else
    {
        /* It's not going to be negative. */
        is_negative = FALSE;

        /* But there may be a sign we will choose to
           ignore. */
        if(c == '+')
            str++;
    }

    c = (*str);

    /* There may be a leading '0x' to indicate that what
       follows is a hexadecimal number. */
    if(base == 0 || base == 16)
    {
        if((c == '0') && (str[1] == 'x' || str[1] == 'X'))
        {
            base = 16;

            str += 2;

            c = (*str);
        }
    }

    /* If we still don't know what base to use and the
       next letter to follow is a zero then this is
       probably a number in octal notation. */
    if(base == 0)
    {
        if(c == '0')
            base = 8;
        else
            base = 10;
    }

    sum = 0;

    if(1 <= base && base <= 36)
    {
        while(c != '\0')
        {
            if('0' <= c && c <= '9')
                c -= '0';
            else if ('a' <= c)
                c -= 'a' - 10;
            else if ('A' <= c)
                c -= 'A' - 10;
            else
                break;

            /* Ignore invalid numbers. */
            if(c >= base)
                break;

            new_sum = base * sum + c;
            if(new_sum < sum) /* overflow? */
            {
                __set_errno(ERANGE);

                result = ULONG_MAX;

                goto out;
            }

            sum = new_sum;

            str++;

            c = (*str);

            num_digits_converted++;
        }
    }

    /* Did we convert anything? */
    if(num_digits_converted == 0)
        goto out;

    if(is_negative)
        result = (-sum);
    else
        result = sum;

    stop = str;

 out:

    /* If desired, remember where we stopped reading the
       number from the buffer. */
    if(ptr != NULL)
        (*ptr) = (char *)stop;

    RETURN(result);
    return(result);
}