Wcstoul.c

/*++

    toro C Library
    https://github.com/KilianKegel/toro-C-Library#toro-c-library-formerly-known-as-torito-c-library

    Copyright (c) 2017-2024, Kilian Kegel. All rights reserved.
    SPDX-License-Identifier: GNU General Public License v3.0

Module Name:

    wcstoul.c

Abstract:

    Implementation of the Standard C function.
    Convert a wide string to an unsigned long-integer value.


Author:

    Kilian Kegel

--*/
#include <limits.h>

extern int _cdeSwscanf(const wchar_t* pwcsBuffer, wchar_t** endptr, const wchar_t* pwcsFormat, ...);

/**

Synopsis
    #include <wchar.h>
    unsigned long wcstoul(const wchar_t *strSource,wchar_t **endptr,int base);
Description
    https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/strtoul-strtoul-l-wcstoul-wcstoul-l?view=msvc-160
    https://www.open-std.org/JTC1/SC22/WG14/www/docs/n1256.pdf#page=387
Paramaters
    https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/strtoul-strtoul-l-wcstoul-wcstoul-l?view=msvc-160#parameters
Returns
    https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/strtoul-strtoul-l-wcstoul-wcstoul-l?view=msvc-160#return-value

**/
unsigned long wcstoul(const wchar_t* s, wchar_t** endptr, int base) {
    unsigned long long l = 0;           // NOTE: initialize to 0 because in error case 0 is returned
    long long* pl = (long long *)&l;
    wchar_t Format[] = { L"%ll`00b" };

    Format[5] = (base /= 1) % 10 + '0';
    Format[4] = (base /= 10) % 10 + '0';

    _cdeSwscanf(s, endptr, Format, &l);

    return (unsigned long)(*pl <= -4294967296LL || *pl >= +4294967296LL ? ULONG_MAX : l);
}