XTCE13 — Another Potential Usability Issue in Draft 1.3 Specification

In the SequenceContainer (also CommandContainer) elements, there is a BinaryEncoding element that contains a SizeInBits element. The SizeInBits element is now optional, but it is not an IntegerValueType. It appears there was a user of a non-fixed sizing value in this field. In the draft, this can only be a fixed numeric value.

Propose to correct the SizeInBits change in 1.3 draft

For backwards compatibility, we propose to restore the previous options within the SizeInBits element, but retain the case of the element being optional when using the BinaryEncoding element.

The post-ballot 16 content of the ContainerBinaryDataEncodingType is:

<complexType name="ContainerBinaryDataEncodingType">
<annotation>
<documentation xml:lang="en">Describe container binary data that is unmolested in the decoding/encoding or cannot be represented in any of the other data encoding formats. Optionally use the FromBinaryTransformAlgorithm and ToBinaryTransformAlgorithm element to describe the transformation process. See InputAlgorithmType for the transformation structure.</documentation>
</annotation>
<sequence>
<element name="ErrorDetectCorrect" type="xtce:ErrorDetectCorrectType" minOccurs="0">
<annotation>
<documentation xml:lang="en">Describes the optional inclusion of an error detection and/or correction algorithm used with this container.</documentation>
</annotation>
</element>
<element name="SizeInBits" type="xtce:PositiveLongType" minOccurs="0">
<annotation>
<documentation xml:lang="en">Number of bits this container occupies on the stream being encoded/decoded. This is only needed to "force" the bit length of the container to be a fixed value. In most cases, the entry list would define the size of the container.</documentation>
</annotation>
</element>
<element name="FromBinaryTransformAlgorithm" type="xtce:InputAlgorithmType" minOccurs="0">
<annotation>
<documentation xml:lang="en">Used to convert binary data to an application data type.</documentation>
</annotation>
</element>
<element name="ToBinaryTransformAlgorithm" type="xtce:InputAlgorithmType" minOccurs="0">
<annotation>
<documentation xml:lang="en">Used to convert binary data from an application data type to binary data.</documentation>
</annotation>
</element>
</sequence>
</complexType>

Change just the SizeInBits element type of PositiveLongType (above) to IntegerValueType:

<complexType name="ContainerBinaryDataEncodingType">
<annotation>
<documentation xml:lang="en">Describe container binary data that is unmolested in the decoding/encoding or cannot be represented in any of the other data encoding formats. Optionally use the FromBinaryTransformAlgorithm and ToBinaryTransformAlgorithm element to describe the transformation process. See InputAlgorithmType for the transformation structure.</documentation>
</annotation>
<sequence>
<element name="ErrorDetectCorrect" type="xtce:ErrorDetectCorrectType" minOccurs="0">
<annotation>
<documentation xml:lang="en">Describes the optional inclusion of an error detection and/or correction algorithm used with this container.</documentation>
</annotation>
</element>
<element name="SizeInBits" type="xtce:IntegerValueType" minOccurs="0">
<annotation>
<documentation xml:lang="en">Number of bits this container occupies on the stream being encoded/decoded. This is only needed to "force" the bit length of the container to be a fixed value. In most cases, the entry list would define the size of the container.</documentation>
</annotation>
</element>
<element name="FromBinaryTransformAlgorithm" type="xtce:InputAlgorithmType" minOccurs="0">
<annotation>
<documentation xml:lang="en">Used to convert binary data to an application data type.</documentation>
</annotation>
</element>
<element name="ToBinaryTransformAlgorithm" type="xtce:InputAlgorithmType" minOccurs="0">
<annotation>
<documentation xml:lang="en">Used to convert binary data from an application data type to binary data.</documentation>
</annotation>
</element>
</sequence>
</complexType>