Class Iso8211DataDescriptiveRecordReader

Namespace

EncDotNet.Iso8211

Assembly

EncDotNet.Iso8211.dll

Parses the Data Descriptive Record (DDR) of an ISO 8211 document and produces a strongly-typed Iso8211DataDescriptiveRecord.

public static class Iso8211DataDescriptiveRecordReader

Inheritance

object

Iso8211DataDescriptiveRecordReader

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

The DDR is the first record in an ISO 8211 file and has a leader identifier of 'L'. Each field in the DDR (except the reserved tag "0000") describes the structure and format of a corresponding field in data records.

Each DDR field's data contains:

1. Field controls — The first bytes (length specified by the record leader's FieldControlLength) contain the data structure code and data type code.
2. Field name and subfield descriptors — Following the field controls, a unit-terminator-delimited section contains the field name and subfield names (separated by ! for vectors or * for repeating groups).
3. Format controls — After the subfield descriptors, a format string (e.g., (A,I(10),b11)) describes the encoding of each subfield.

Methods

GetDdrFieldDefinition(int)

Gets (or creates and caches) an Iso8211FieldDefinition that describes the internal structure of any DDR field entry for the given field control length.

public static Iso8211FieldDefinition GetDdrFieldDefinition(int fieldControlLength)

Parameters

fieldControlLength int

The field control length from the DDR leader.

Returns

Iso8211FieldDefinition

An Iso8211FieldDefinition describing the DDR's own field structure.

Remarks

Since the DDR is itself a standard ISO 8211 record, its fields follow a known structure defined by the ISO 8211 standard. This method returns a meta-DDR field definition — a single definition that describes the layout shared by all DDR fields — enabling the use of Iso8211FieldReader to parse DDR field data.

Every DDR field has the same internal layout, determined solely by fieldControlLength:

• Field controls (fixed-width, size determined by fieldControlLength): data structure code (1 byte) and data type code (1 byte), plus any additional control bytes.
• Field name / descriptors (variable-length, unit-terminated).
• Subfield labels or array descriptor (variable-length, unit-terminated).
• Format controls (variable-length, terminated by end of field).

The returned definition is cached by fieldControlLength, so repeated calls with the same value return the same instance without additional allocations.

Read(Iso8211Record)

Parses an Iso8211Record that represents a DDR and returns a strongly-typed Iso8211DataDescriptiveRecord.

public static Iso8211DataDescriptiveRecord Read(Iso8211Record record)

Parameters

record Iso8211Record

The ISO 8211 record to parse. Must be a DDR (leader identifier 'L').

Returns

Iso8211DataDescriptiveRecord

The parsed DDR containing all field definitions.

Exceptions

ArgumentException

Thrown when the record is not a DDR.