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All incoming records are of the same record type, however their content varies. The first four fields are present in all records, the fifth field varies depending on the content of the field RecordOwnerTypePresent. The last three fields are optional.
A schematic representation of the example discussed in this section
external
Since the last three optional fields (including RecordOwnerType and RecordOwnerDN) consist of several fields, each one will be defined as its own type. That is, an external sequential format.
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The |
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/ Filler needed to be able to recognize on the input stream:
external FillerRecord_0x00_EXT:
identified_by(RecordIdentifier == 0x00), static_size(32)
{
int(little_endian) RecordIdentifier : static_size(1),
external_only, encode_value(0x00);
// Note that no other fields are specified.
// The UDR size (32) will be consumed and discarded (see in_map).
}; |
Alternative Syntax
An alternative to use the set construct, in the external definition for AMARecord_ext, switched_set could be used. This will impact the syntax for the Package_*_EXT types. Only the syntax differing from the original example is shown. The main reason for using switched_set instead of set is when performance must be increased.
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No |
internal
No internal is used. In this case, the target_internal is sufficient; all field names and field types are in order and there is only one type of record present in the input, and no additional fields are required.
in_map
The padding in the records is recognized by the decoder, however it is not actually mapped in to the system due to the use of the discard_output flag.
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in_map FillerRecord_0x00_Map :
external(FillerRecord_0x00_EXT),
target_internal(FillerRecord_0x00),
discard_output {
automatic;
};
in_map AMARecord_Map : external(AMARecord_EXT),
target_internal( AMARecord ) {
automatic {
RecordOwnerType_EXT : target_internal( RecordOwnerType );
RecordOwnerDN_EXT : target_internal( RecordOwnerDN );
Package_100_EXT : target_internal( Package_100 );
Package_101_EXT : target_internal( Package_101 );
Package_102_EXT : target_internal( Package_102 );
};
}; |
decoder
The padding pseudo-records and data records can arrive in any order, therefore there is no need to define a constructed decoder.
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decoder AMAFile : in_map( AMARecord_Map ),
in_map( FillerRecord_0x00_Map ); |
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