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                                              104
CHAPTER 3                                                                       Syntax



      >>
   endobj

   ...


   xref
   0 32
   0000000000 65535 f
   ...
   0000001434 00000 n         % Cross-reference entry for object 11
   0000001735 00000 n         % Cross-reference entry for object 12
   0000002155 00000 n         % Cross-reference entry for object 13
   ...
   trailer
       << /Size 32
           /Root ...
       >>

In Example 3.9, the cross-reference stream (see Section 3.4.7, “Cross-Reference
Streams”) contains entries for the fonts (objects 11 and 13) and the descriptor
(object 12), which are compressed objects in an object stream. The first field of
these entries is the entry type (2), the second field is the number of the object
stream (15), and the third field is the position within the sequence of objects in
the object stream (0, 1, and 2). The cross-reference stream also contains a type 1
entry for the object stream itself.

Note: For readability, the object stream has been shown unencoded. In a real PDF
1.5 file, Flate encoding would typically be used to gain the benefits of compression.

Example 3.9

   15 0 obj                % The object stream
       << /Type /ObjStm
          /Length 1856
          /N 3             % The number of objects in the stream
          /First 24        % The byte offset of the first object
       >>
   stream
       % The object numbers and offsets of the objects, relative to the first
       11 0 12 547 13 665
       << /Type /Font
          /Subtype /TrueType
          ...other keys...

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