RtlUnicodeStringInitWorker - NtDoc

#ifndef _NTSTRSAFE_H_INCLUDED_
#ifndef NTSTRSAFE_NO_UNICODE_STRING_FUNCTIONS

_At_(DestinationString->Buffer, _Post_equal_to_(pszSrc))
_At_(DestinationString->Length, _Post_equal_to_(_String_length_(pszSrc) * sizeof(WCHAR)))
_At_(DestinationString->MaximumLength, _Post_equal_to_((_String_length_(pszSrc)+1) * sizeof(WCHAR)))
NTSTRSAFEWORKERDDI
RtlUnicodeStringInitWorker(
        _Out_ PUNICODE_STRING DestinationString,
        _In_opt_ NTSTRSAFE_PCWSTR pszSrc,
        _In_ const size_t cchMax,
        _In_ DWORD dwFlags);

#endif
#endif
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#ifndef _NTSTRSAFE_H_INCLUDED_
// Below here are the worker functions that actually do the work
#if defined(NTSTRSAFE_LIB_IMPL) || !defined(NTSTRSAFE_LIB)
#ifndef NTSTRSAFE_NO_UNICODE_STRING_FUNCTIONS

_Use_decl_annotations_
NTSTRSAFEWORKERDDI
RtlUnicodeStringInitWorker(
        PUNICODE_STRING DestinationString,
        NTSTRSAFE_PCWSTR pszSrc,
        const size_t cchMax,
        DWORD dwFlags)
{
    NTSTATUS status = STATUS_SUCCESS;

    if (DestinationString || !(dwFlags & STRSAFE_IGNORE_NULLS))
    {
        memset(DestinationString, 0, sizeof(*DestinationString));
    }

    if (pszSrc)
    {
        size_t cchSrcLength;

        status = RtlStringLengthWorkerW(pszSrc, cchMax, &cchSrcLength);

        if (NT_SUCCESS(status))
        {
            if (DestinationString)
            {
                size_t cbLength;

                // safe to multiply cchSrcLength * sizeof(wchar_t) since cchSrcLength < NTSTRSAFE_UNICODE_STRING_MAX_CCH and sizeof(wchar_t) is 2
                cbLength = cchSrcLength * sizeof(wchar_t);

                DestinationString->Length = (USHORT)cbLength;
                // safe to add cbLength + sizeof(wchar_t) since cchSrcLength < NTSTRSAFE_UNICODE_STRING_MAX_CCH
                DestinationString->MaximumLength = (USHORT)(cbLength + sizeof(wchar_t));
                DestinationString->Buffer = (PWSTR)pszSrc;
            }
            else
            {
                status = STATUS_INVALID_PARAMETER;
            }
        }
    }

    return status;
}

#endif
#endif
#endif
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#ifndef _NTSTRSAFE_H_INCLUDED_
// Do not call these functions, they are worker functions for internal use within this file
#ifdef DEPRECATE_SUPPORTED
// ...
#else

#define RtlUnicodeStringInitWorker          RtlUnicodeStringInitWorker_instead_use_RtlUnicodeStringInit_or_RtlUnicodeStringInitEx

#endif
#endif
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