SECTION 3.10
191
File Specifications
specification dictionary. In Example 3.21 on page 187, for instance, the
EF
dictionary has a
DOS
entry identifying object number 21 as an embedded file
stream. The name of the embedded DOS file,
SUNSET. EPS
, is given by the
DOS
entry in the file specification dictionary.
A given external file may be referenced from more than one file specification.
Therefore, when embedding a file with a given name, it is necessary to check for
other occurrences of the same name as the value associated with the
corresponding key in other file specification dictionaries. This requires finding
all embeddable file specifications and, for each matching key, checking for both
of the following conditions:
•
The string value associated with the key matches the name of the file being em-
bedded.
•
A value has not already been embedded for the file specification. (If there is
already a corresponding key in the
EF
dictionary, a file has already been em-
bedded for that use of the file name.)
Note that there is no requirement that the files associated with a given file name
be unique. The same file name, such as
readme . txt
, may be associated with
different embedded files in distinct file specifications.