mbeckerle commented on a change in pull request #643: URL: https://github.com/apache/daffodil/pull/643#discussion_r716861378
########## File path: daffodil-test/src/test/resources/org/apache/daffodil/layers/xsd/IPv4ChecksumLayer.dfdl.xsd ########## @@ -0,0 +1,51 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!-- + Licensed to the Apache Software Foundation (ASF) under one or more + contributor license agreements. See the NOTICE file distributed with + this work for additional information regarding copyright ownership. + The ASF licenses this file to You under the Apache License, Version 2.0 + (the "License"); you may not use this file except in compliance with + the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +--> +<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"; + xmlns:dfdl="http://www.ogf.org/dfdl/dfdl-1.0/"; + xmlns:dfdlx="http://www.ogf.org/dfdl/dfdl-1.0/extensions"; + xmlns:fn="http://www.w3.org/2005/xpath-functions"; + xmlns:daf="urn:ogf:dfdl:2013:imp:daffodil.apache.org:2018:ext" + xmlns:tns="urn:org.apache.daffodil.layers.IPv4Checksum" + targetNamespace="urn:org.apache.daffodil.layers.IPv4Checksum"> + + <xs:annotation> + <xs:documentation> + Variable for the layer transform used for IPv4 checksum calculation. + + Per the checksum algorithm described in IETF RFC791. + + The data has a well-known fixed layer length. Hence, layerLengthKind is 'implicit'. + + If the data doesn't match this expected fixed length, issue PE/UE. + + This checksum is written into the result variable. + </xs:documentation> + <xs:appinfo source="http://www.ogf.org/dfdl/";> + <dfdl:defineVariable name="IPv4Checksum" type="xs:unsignedShort"/> + <dfdl:defineFormat name="IPv4ChecksumLayer"> + <dfdl:format dfdlx:layerTransform='{ "IPv4Checksum" }' dfdlx:layerLengthKind="implicit"/> + </dfdl:defineFormat> + </xs:appinfo> + </xs:annotation> + + <xs:simpleType name="IPv4Checksum" + dfdl:lengthKind="explicit" dfdl:length="16" dfdl:lengthUnits="bits"> + <xs:restriction base="xs:unsignedShort"/> Review comment: I think you will get a text integer, and if the charset is say, ascii, you'll get a 2-byte long (2 ascii chars) integer since that's what would fit in 16 bits. Seems weird, but there are data specs where they tell you how long every field is, in bits, even for the text strings, purely for uniformity reasons in the spec. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
