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                                               160
      CHAPTER 3                                                                      Syntax



      represent characters but the encoding is not known. The bytes of the string may
      not represent characters.

      Note: This type is not a true type. Rather, it is a string type that represents data
      whose encoding is unknown.


3.8.2 Text Streams

      A text stream (PDF 1.5) is a PDF stream object (Section 3.2.7) whose unencoded
      bytes meet the same requirements as a text string (“Text String Type” on page
      158) with respect to encoding, byte order, and lead bytes.


3.8.3 Dates

      PDF defines a standard date format, which closely follows that of the
      international standard ASN.1 (Abstract Syntax Notation One), defined in ISO/
      IEC 8824 (see the Bibliography). A date is an ASCII string of the form

         ( D : YYYYMMDDHHmmSSOHH ' mm ' )

      where
        YYYY is the year
        MM is the month
        DD is the day (01–31)
        HH is the hour (00–23)
        mm is the minute (00–59)
        SS is the second (00–59)
        O is the relationship of local time to Universal Time (UT), denoted by one of
        the characters +, −, or Z (see below)
        HH followed by ' is the absolute value of the offset from UT in hours (00–23)
        mm followed by ' is the absolute value of the offset from UT in minutes (00–59)

      The apostrophe character ( ' ) after HH and mm is part of the syntax. All fields after
      the year are optional. (The prefix D : , although also optional, is strongly
      recommended.) The default values for MM and DD are both 01; all other

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