Windows内核STRING转UNICODE

VOID
ConvertToUnicodeString(
    IN CHAR * Buffer,
    IN ULONG ResultBufferLength,
    IN ULONG ResultBufferOffset,
    OUT LPWSTR ResultBuffer,
    OUT PULONG NewResultBufferOffset)
{
    UNICODE_STRING DeviceString;
    ANSI_STRING AnsiString;
    NTSTATUS Status;

    ASSERT(ResultBufferLength);
    ASSERT(ResultBufferLength > ResultBufferOffset);

    DPRINT("ResultBufferOffset %lu ResultBufferLength %lu Buffer %s Length %lu\n", ResultBufferOffset, ResultBufferLength, Buffer, strlen(Buffer));

    //
    // construct destination string
    //
    DeviceString.Buffer = &ResultBuffer[ResultBufferOffset];
    DeviceString.Length = 0;
    DeviceString.MaximumLength = (ResultBufferLength - ResultBufferOffset) * sizeof(WCHAR);

    //
    // initialize source string
    //
    RtlInitAnsiString(&AnsiString, Buffer);

    //
    // convert to unicode
    //
    Status = RtlAnsiStringToUnicodeString(&DeviceString, &AnsiString, FALSE);
    ASSERT(Status == STATUS_SUCCESS);

    //
    // subtract consumed bytes
    //
    ResultBufferLength -= (DeviceString.Length + sizeof(WCHAR)) / sizeof(WCHAR);
    ResultBufferOffset += (DeviceString.Length + sizeof(WCHAR)) / sizeof(WCHAR);

    //
    // store new offset
    //
    *NewResultBufferOffset = ResultBufferOffset;
}