Hi Steve,
The EXE specification is silent on the number of occurrences of the
Import_Lookup_Table. All I know is that once we see the first Hint_Name_Table
entry (a 2-byte address, followed by a null-terminated name, followed by an
optional null) then we know that there are no more Import_Lookup_Tables. Is
there a way to express (for Import_Lookup_Table):
There are no more occurrences
once we encounter a 2-byte
address, followed by a null-terminated
string, followed by an optional
null.
Is it possible to express that?
/Roger
-----Original Message-----
From: Steve Lawrence <[email protected]>
Sent: Sunday, March 3, 2019 11:25 AM
To: [email protected]; Costello, Roger L. <[email protected]>
Subject: [EXT] Re: Need help informing Daffodil that we're finished with this
field and it's time to build the next field
I think we need more information, specifically how do you know what is the last
Import_Lookup_Table?
Within an Import_Lookup_Table you say that the Lookup_Table_Entry ends with the
last entry is all nulls, but that doesn't tell us where the last
Import_Lookup_Table is. Is it when there's a special value of a
Lookup_Table_Entry? Or maybe when the Import_Lookup_table has a no
Lookup_Table_Entires and just has the terminating Null? Something else?
You'll likely need to add a discriminator somewhere, but we'd need more
information to know what that discriminator should be.
- Steve
On 3/3/19 7:55 AM, Costello, Roger L. wrote:
> Hello DFDL community,
>
> In the Windows EXE file format there is one or more
> Import_Lookup_Tables followed by a Hint_Name_Table. I am struggling
> with how to inform Daffodil, "Hey Daffodil, the input is finished with
> the Import_Lookup_Tables, now it's time to build the Hint_Name_Table."
> I am hoping you can show me how to inform Daffodil of this.
>
> Each Import_Lookup_Table consists of one of more 32-bit fields,
> terminated by a 32-bit field containing all nulls.
>
> The Hint_Name_Table consists of one of more entries; each entry
> consists of a 2-byte address, followed by a null-terminated name,
> followed by an optional null (to align to a 2-byte boundary).
>
> Here is a graphic that illustrates the Import_Lookup_Tables followed
> by the
> Hint_Name_Table:
>
> Here is the relevant portion of my DFDL schema:
>
> <xs:elementname="idata_Section">
> <xs:complexType>
> <xs:sequence>>
> <xs:elementref="Import_Lookup_Table"
> maxOccurs="unbounded"/>
> <xs:elementref="Hint_Name_Table"/>
> </xs:sequence>
> </xs:complexType>
> </xs:element>
>
> <xs:elementname="Import_Lookup_Table">
> <xs:complexType>
> <xs:sequence>
> <xs:elementref="Lookup_Table_Entry"
> maxOccurs="unbounded"/>
> <xs:elementname="Null_Lookup_Table_Entry"
> type="xs:hexBinary"
> dfdl:lengthKind="explicit"
> dfdl:length="4"
> dfdl:lengthUnits="bytes"> <xs:annotation>
> <xs:appinfosource="http://www.ogf.org/dfdl/";>
> <dfdl:assert>
> { . eq xs:hexBinary("00000000") }
> </dfdl:assert> </xs:appinfo> </xs:annotation> </xs:element>
> </xs:sequence> </xs:complexType> </xs:element>
>
> How do I inform Daffodil that the input has finished with the
> Import_Lookup_Tables?
>
> /Roger
>
