Index Element (IEL) structured field

The IEL structured field associates indexing tags with a specific page or group of pages in the output document file.

It also contains the byte and structured field offset to the page or page group and the size of the page or page group in both bytes and structured field count. The following is a list of the triplets that compose this structured field:
  • FQN Type X'8D'

    This triplet contains the name of the active medium map associated with the page or page group. In the case of page groups, this is the medium map that is active for the first page in the group, because other medium maps can be referenced after subsequent pages in the group. If no medium map is explicitly invoked with an Invoke Medium Map (IMM) structured field, ACIF uses a null name (8 bytes of X'FF') to identify the default medium map; that is, the first medium map in the form definition.

  • Object Byte Extent (X'57')

    This triplet contains the size, in bytes, of the page or group this IEL structured field references. The value begins at 1.

  • Object Structured Field Extent (X'59')

    This triplet contains the number of structured fields that compose the page or group referenced by this IEL structured field. In the host environment, each record contains only one structured field, so this value also represents the number of records in the page or group. The value begins at 1.

  • Direct Byte Offset (X'2D')

    This triplet contains the offset, in bytes, from the start of the output print file to the particular page or group this IEL structured field references. The value begins at 0.

  • Object Structured Field Offset (X'58')

    This triplet contains the offset, in number of structured fields, from the start of the output print file to the start of the particular page or group this IEL structured field references. The value begins at 0.

  • FQN Type X'87'

    This triplet contains the name of the page with which this IEL structured field is associated. The name is the same as the FQN type X'01' on the BPG structured field. This triplet applies only to page-level IEL structured fields.

  • FQN Type X'0D'

    This triplet contains the name of the page group with which this IEL structured field is associated. The name is the same as the FQN type X'01' on the BNG structured field. This triplet applies only to group-level IEL structured fields.

  • Medium Map Page Number (X'56')

    This triplet defines the relative page count since the last Invoke Medium Map (IMM) structured field was processed or from the logical invocation of the default medium map. In the case of page groups, this value applies to the first page in the group. The value begins at 1 and is incremented for each page.