APPENDIX F
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Linearized PDF
A single entry in the shared object hint table can actually describe a group of ad-
jacent objects under the following condition: Only the first object in the group is
referenced from outside the group; the remaining objects in the group are refer-
enced only from other objects in the same group. The objects in a group must
have adjacent object numbers.
The page offset hint table, interactive form hint table, and logical structure hint
table refer to an entry in the shared object hint table by a simple index that is its
sequential position in the table, counting from 0.
The shared object hint table consists of a header section (Table F.5) followed by
one or more shared object group entries (Table F.6). There are two sequences of
shared object group entries: the ones for objects located in the first page, followed
by the ones for objects located in the shared objects section. The entries have the
same format in both cases. Note that the items making up each shared object
group entry are not contiguous; they are broken up with items from entries for
other shared object groups. The order of items in each sequence is as follows:
1. Item 1 for the first group, item 1 for the second group, and so on
2. Item 2 for the first group, item 2 for the second group, and so on
3. Item 3 for the first group, item 3 for the second group, and so on
4. Item 4 for the first group, item 4 for the second group, and so on
All objects associated with the first page (part 6) have entries in the shared object
hint table, regardless of whether they are actually shared. The first entry refers to
the beginning of the first page and has an object count and length that span all
the initial nonshared objects. The next entry refers to a group of shared objects.
Subsequent entries span additional groups of either shared or nonshared objects
consecutively until all shared objects in the first page have been enumerated.
(The entries that refer to nonshared objects are never used.)
TABLE F.5 Shared object hint table, header section
ITEM
SIZE (BITS)
DESCRIPTION
1
2
3
32
32
32
The object number of the first object in the shared objects section (part 8).
The location of the first object in the shared objects section.
The number of shared object entries for the first page (including nonshared
objects, as noted above).