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1045
SECTION F.3 Hint Tables
ITEM SIZE (BITS) DESCRIPTION
4 32 The number of shared object entries for the shared objects section, including
the number of shared object entries for the first page (that is, the value of
item 3).
5 16 The number of bits needed to represent the greatest number of objects in a
shared object group. (See also implementation note 185 in Appendix H.)
6 32 The least length of a shared object group in bytes.
7 16 The number of bits needed to represent the difference between the greatest
and least length of a shared object group, in bytes.
TABLE F.6 Shared object hint table, shared object group entry
ITEM SIZE (BITS) DESCRIPTION
1 See Table F.5, item 7 A number that, when added to the least shared object group length (Table F.5,
item 6), gives the length of the object group in bytes. The location of the first
object of the first page is given in the page offset hint table, header section
(Table F.3, item 4). The locations of subsequent object groups can be deter-
mined by accumulating the lengths of all previous object groups until all
shared objects in the first page have been enumerated. Following that, the
location of the first object in the shared objects section can be obtained from
the header section of the shared object hint table (Table F.5, item 2).
2 1 A flag indicating whether the shared object signature (item 3) is present; its
value is 1 if the signature is present and 0 if it is absent. (See also implementa-
tion note 186 in Appendix H.)
3 128 (Only if item 2 is 1) The shared object signature, a 16-byte MD5 hash that
uniquely identifies the resource that the group of objects represents. It is in-
tended to enable the client to substitute a locally cached copy of the resource
instead of reading it from the PDF file. Note that this signature is unrelated to
signature fields in interactive forms, as defined in the section “Signature
Fields” on page 695.
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