CHAPTER 3
160
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
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