UDF 2.00 - OSTA - Optical Storage Technology Association

The value of the OSTA Compressed Unicode d-character interpreted as a Uint16
defines the value of the corresponding d-character in the Unicode 2.0 standard.
Refer to appendix on OSTA Compressed Unicode for sample C source code to
convert between OSTA Compressed Unicode and standard Unicode 2.0.
The Unicode byte-order marks, #FEFF and #FFFE, shall not be used.
A Compression ID of 254 or 255 shall indicate that the following 4 or 8 bytes
respectively contain a binary value unique to the context. E.g. File Identifiers may
use a Compression ID of 254 or 255 and a byte offset of the FID within the
directory to create unique directory entries when the Deleted bit is set.
2.1.2 OSTA CS0 Charspec
struct charspec { /* ECMA 167 1/7.2.1 */
Uint8
CharacterSetType;
byte
CharacterSetInfo[63];
}
The CharacterSetType field shall have the value of 0 to indicate the CS0 coded
character set.
The CharacterSetInfo field shall contain the following byte values with the
remainder of the field set to a value of 0.
#4F, #53, #54, #41, #20, #43, #6F, #6D, #70, #72, #65, #73, #73, #65,
#64, #20, #55, #6E, #69, #63, #6F, #64, #65
The above byte values represent the following ASCII string:
“OSTA Compressed Unicode”
2.1.3 Dstrings
The ECMA 167 standard, as well as this document, has normally defined byte positions
relative to 0. In section 7.2.12 of ECMA 167, dstrings are defined in terms of being
relative to 1. Since this offers an opportunity for confusion, the following shows what the
definition would be if described relative to 0.
7.2.12 Fixed-length character fields
A dstring of length n is a field of n bytes where d-characters (1/7.2) are recorded. The number of
bytes used to record the characters shall be recorded as a Uint8 (1/7.1.1) in byte n-1, where n is
the length of the field. The characters shall be recorded starting with the first byte of the field,
and any remaining byte positions after the characters up until byte n-2 inclusive shall be set to
#00.
UDF 2.00 April 3, 1998
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