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                                                    1030
          APPENDIX F                                                                 Linearized PDF



PARAMETER        TYPE            VALUE

T                integer         (Required) In documents that use standard main cross-reference tables (in-
                                 cluding hybrid-reference files; see “Compatibility with Applications That Do
                                 Not Support PDF 1.5” on page 109), this entry represents the offset of the
                                 white-space character preceding the first entry of the main cross-reference
                                 table (the entry for object number 0), relative to the beginning of the file.
                                 Note that this differs from the Prev entry in the first-page trailer, which gives
                                 the location of the xref line that precedes the table.
                                 In PDF 1.5 and later documents that use cross-reference streams exclusively
                                 (see Section 3.4.7, “Cross-Reference Streams”), this entry represents the off-
                                 set of the main cross-reference stream object.

P                integer         (Optional) The page number of the first page (see Section F.2.6, “First-Page
                                 Section (Part 6)”). Default value: 0.


    F.2.3 First-Page Cross-Reference Table and Trailer (Part 3)

          Part 3 contains the cross-reference table for objects belonging to the first page
          (discussed in Section F.2.6, “First-Page Section (Part 6)”) as well as for the docu-
          ment catalog and document-level objects appearing before the first page (dis-
          cussed in Section F.2.4, “Document Catalog and Document-Level Objects (Part
          4)”). Additionally, this cross-reference table contains entries for the linearization
          parameter dictionary (at the beginning) and the primary hint stream (at the end).
          This table is a valid cross-reference table as defined in Section 3.4.3, “Cross-
          Reference Table,” although its position in the file is unconventional. It consists of
          a single cross-reference subsection that has no free entries.

          Note: In PDF 1.5 and later, cross-reference streams (see Section 3.4.7, “Cross-Refer-
          ence Streams”) may be used in linearized files in place of traditional cross-reference
          tables. The logic described in this section, along with the appropriate syntactic
          changes for cross-reference streams, still applies.

          Below the table is the first-page trailer. The trailer’s Prev entry gives the offset of
          the main cross-reference table near the end of the file. This is valid PDF syntax,
          although the trailers are linked in an unusual order. A PDF viewer application
          that is unaware of linearization interprets the first-page cross-reference table as
          an update to an original document that is indexed by the main cross-reference ta-
          ble.

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