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CHAPTER 3 Syntax
TABLE 3.43 Entries in an embedded file parameter dictionary
KEY TYPE VALUE
Size integer (Optional) The size of the embedded file, in bytes.
CreationDate date (Optional) The date and time when the embedded file was created.
ModDate date (Optional) The date and time when the embedded file was last modified.
Mac dictionary (Optional) A subdictionary containing additional information specific to
Mac OS files (see Table 3.44).
CheckSum string (Optional) A 16-byte string that is the checksum of the bytes of the uncom-
pressed embedded file. The checksum is calculated by applying the standard
MD5 message-digest algorithm (described in Internet RFC 1321, The MD5
Message-Digest Algorithm; see the Bibliography) to the bytes of the embedded
file stream.
For Mac OS files, the Mac entry in the embedded file parameter dictionary holds
a further subdictionary containing Mac OS–specific file information. Table 3.44
shows the contents of this subdictionary.
TABLE 3.44 Entries in a Mac OS file information dictionary
KEY TYPE VALUE
Subtype integer (Optional) The embedded file’s file type. It is encoded as an integer according to Mac
OS conventions: a 4-character ASCII text literal, converted to a 32-bit integer, with the
high-order byte first. For example, the file type 'CARO' is represented as the hexadeci-
mal integer 4341524F, which is expressed in decimal as 1128354383.
Creator integer (Optional) The embedded file’s creator signature, encoded in the same way as Subtype.
ResFork stream (Optional) The binary contents of the embedded file’s resource fork.
Related Files Arrays
In some circumstances, a PDF file can refer to a group of related files, such as the
set of five files that make up a DCS 1.0 color-separated image. The file
specification explicitly names only one of the files; the rest are identified by some
systematic variation of that file name (such as by altering the extension). When
such a file is to be embedded in a PDF file, the related files must be embedded as
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