Bug with hidden group containing an element with a 1-bit value?

[Costello, Roger L.]

Hello DFDL community,

I am creating a DFDL schema for .exe files (Portable Executable file format).

At one point in the file are 2-bytes that represent sixteen 1-bit flags.

For each bit, if the bit = 1, then I want to output a message; otherwise output 
0 (for now).

To test that I am correctly reading the 2 bytes I did this:

<xs:element name="Characteristics" type="xs:hexBinary" dfdl:length="2" 
dfdl:lengthKind="explicit" dfdl:lengthUnits="bytes" />

The output contained the correct hex bytes:

        07 01

To test that I am correctly consuming each individual bit I did this:

<xs:element name="Characteristic" type="unsignedint1" minOccurs="16" 
maxOccurs="16" />

Here is the output:

    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>1</Characteristic>
    <Characteristic>1</Characteristic>
    <Characteristic>1</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>0</Characteristic>
    <Characteristic>1</Characteristic>

You can see that those bits correspond to hex 07 01.

I want the value of each <Characteristic> element to be a message, not 0/1. So, 
I used the dfdl:hiddenGroupRef approach to translate 0/1 to a message.

<xs:element name="Characteristics">
    <xs:complexType>
        <xs:sequence>
            <xs:sequence 
dfdl:hiddenGroupRef="hidden_characteristic_bit16_Group" />
            <xs:element name="Characteristic-16" type="xs:string" 
dfdl:inputValueCalc="{
                    if 
(fn:lower-case(xs:string(../Hidden_characteristic_bit16)) eq "1") then "The 
bytes of the word are reversed(obsolete)"  
                    else xs:string(../Hidden_characteristic_bit16)}" />
            <xs:sequence 
dfdl:hiddenGroupRef="hidden_characteristic_bit15_Group" />
            <xs:element name="Characteristic-15" type="xs:string" 
dfdl:inputValueCalc="{
                    if 
(fn:lower-case(xs:string(../Hidden_characteristic_bit15)) eq "1") then "The 
image should only be run on a single processor computer"  
                    else xs:string(../Hidden_characteristic_bit15)}" />
            ...
        </xs:sequence>
    </xs:complexType>
</xs:element>

<xs:group name="hidden_characteristic_bit16_Group"> 
    <xs:sequence>
        <xs:element name="Hidden_characteristic_bit16" type="unsignedint1" 
dfdl:outputValueCalc="{ . }" />
    </xs:sequence>
</xs:group>
...
<xs:group name="hidden_characteristic_bit1_Group"> 
    <xs:sequence>
        <xs:element name="Hidden_characteristic_bit1" type="unsignedint1" 
dfdl:outputValueCalc="{ . }" />
    </xs:sequence>
</xs:group>

That produced this incorrect output:

<Characteristic-16>0</Characteristic-16>
<Characteristic-15>0</Characteristic-15>
<Characteristic-14>0</Characteristic-14>
<Characteristic-13>0</Characteristic-13>
<Characteristic-12>0</Characteristic-12>
<Characteristic-11>0</Characteristic-11>
<Characteristic-10>0</Characteristic-10>
<Characteristic-9>0</Characteristic-9>
<Characteristic-8>0</Characteristic-8>
<Characteristic-7>0</Characteristic-7>
<Characteristic-6>0</Characteristic-6>
<Characteristic-5>Aggressively trim the working set(obsolete)</Characteristic-5>
<Characteristic-4>0</Characteristic-4>
<Characteristic-3>0</Characteristic-3>
<Characteristic-2>0</Characteristic-2>
<Characteristic-1>0</Characteristic-1>

Is there a bug with hidden groups containing an element with a 1-bit value?

Note: here is how unsigned1 is defined:

<xs:simpleType name="unsignedint1" dfdl:length="1" dfdl:lengthKind="explicit" 
dfdl:alignmentUnits="bits">
        <xs:restriction base="xs:unsignedInt"/>
</xs:simpleType>

/Roger