[jira] [Assigned] (DAFFODIL-1741) Performance - validation of Enum and Ranges for simple type unions

["Michael Beckerle (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DAFFODIL-1741?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Michael Beckerle reassigned DAFFODIL-1741:
------------------------------------------

    Assignee:     (was: Elizabeth Fahl)

> Performance - validation of Enum and Ranges for simple type unions
> ------------------------------------------------------------------
>
>                 Key: DAFFODIL-1741
>                 URL: https://issues.apache.org/jira/browse/DAFFODIL-1741
>             Project: Daffodil
>          Issue Type: Improvement
>          Components: Back End, Middle "End"
>    Affects Versions: 2.0.0
>            Reporter: Michael Beckerle
>             Fix For: deferred
>
>
> DFDL-1634 provides support for simpleType uinons in Daffodil.
> However, a union is still validated (in "limited" validation mode, or when dfdl:checkConstraints is called) by sequentially walking through the union members one by one.
> When the union consists of enumerations, or ranges, or mixtures of only those two, then a faster mechanism is needed. 
> E.g., for a union that is just enumerations, the validation should take constant time, by using a hash/table lookup. 
> For a union of min/max ranges, some sort of decision tree that rapidly determines validity is required. 
> combinations of these are also possible. A common situation would be for the integer 0 to mean "No Statement", 1-25 are valid values that have some mathematical meaning, and 26-31 are illegal.
> We want to express this like
> {code}
> <simpleType>
>    <union memberTypes="ex:noStatement ex:allowed ex:illegal"/>
> </simpleType>
> <simpleType name="noStatement">
>   <restriction base="xs:int">
>      <enumeration value="0"/>
>  </restriction>
> </simpleType>
> <simpleType name="valid">
>    <union memberTypes="ex:car ex:train ex:plane.... ex:bicycle"/
> </simpleType>
> <simpleType name="car"><restriction base="xs:int"><enumeration value="1"/></restriction></simpleType>
> <simpleType name="train"><restriction base="xs:int"><enumeration value="2"/></restriction></simpleType>
> <simpleType name="plane"><restriction base="xs:int"><enumeration value="3"/></restriction></simpleType>
> ... 21 more ...
> <simpleType name="bicycle"><restriction base="xs:int"><enumeration value="25"/></restriction></simpleType>
> <simpleType name="illegal">
>    <restriction base="xs:int">
>        <minInclusive value="26"/>
>       <maxInclusive value="31"/>
>    </restriction>
> </simpleType>
> {code}
>      
> In the above, the union containing the 25 enumeration simple types will be iterated with a loop that will go through all 25 possibles one by one. This needs to be improved to be a constant time dispatch.



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