Internet Draft J. Eberle FastnLight Category: Informational Expires: June 2007 December 2006 Standard Data Types Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Copyright Notice Copyright (C) The Internet Society, December 2006. Eberle Expires June 2007 [Page 1] Internet Draft Standard Data Types December 2006 Abstract This document assigns 25 common data types clear, unambiguous names, and numerical identifiers. It also defines context dependencies, such as byte-order and charset, to the data types, where necessary. 1. Introduction This document attempts to codify a set of common data types, giving each a clear, unambiguous name, and a fixed identifier. The names and identifiers are designed to serve as the basis for higher-level data typing constructs. On their own, the data type names serve to streamline and sharpen technical writing. Eberle Expires June 2007 [Page 2] Internet Draft Standard Data Types December 2006 2. Type Catalog ID Name Coding Bits Domain Context -- ------- --------------- ---- --------------- ------------------- 1 uint1 unsigned integer 1 0 .. 1 2 uint2 unsigned integer 2 0 .. 3 3 uint3 unsigned integer 3 0 .. 7 4 uint4 unsigned integer 4 0 .. 15 5 uint5 unsigned integer 5 0 .. 31 6 uint6 unsigned integer 6 0 .. 63 7 uint7 unsigned integer 7 0 .. 127 -- ------- --------------- ---- --------------- ------------------- 8 uint8 unsigned integer 8 0 .. 255 9 uint16 unsigned integer 16 0 .. 65535 byte-order 10 uint32 unsigned integer 32 0 .. 2^32-1 byte-order 11 uint64 unsigned integer 64 0 .. 2^64-1 byte-order -- ------- --------------- ---- --------------- ------------------- 12 sint8 signed integer 8 -128 .. 127 13 sint16 signed integer 16 -32768 .. 32767 byte-order 14 sint32 signed integer 32 -2^31 .. 2^31-1 byte-order 15 sint64 signed integer 64 -2^63 .. 2^63-1 byte-order -- ------- --------------- ---- --------------- ------------------- 16 float32 floating point 32 +-10^ +-38 byte-order 17 float64 floating point 64 +-10^+-308 byte-order -- ------- --------------- ---- --------------- ------------------- 18 char8 character 8 256 codepoints charset 19 char16 character 16 65536 codepoints charset, byte-order 20 char32 character 32 2^32 codepoints charset, byte-order -- ------- --------------- ---- --------------- ------------------- 21 mb8 multi-byte char 8-32 2^30 codepoints charset 22 mb16 multi-byte char 16-32 2^31 codepoints charset, byte-order -- ------- --------------- ---- --------------- ------------------- 23 bcd4 binary-coded dec 4 0 .. 9, +, - 24 bcd8 binary-coded dec 8 0 .. 9, +, - charset -- ------- --------------- ---- --------------- ------------------- 25 void 0 {} -- ------- --------------- ---- --------------- ------------------- Eberle Expires June 2007 [Page 3] Internet Draft Standard Data Types December 2006 3. Type Details 3.1. Unsigned Integer (uint1, uint2, uint3, uint4, uint5, uint6, uint7, uint8, uint16, uint32, uint64) Representation: Base-2 positional, unsigned. 3.2. Signed Integer (sint8, sint16, sint32, sint64) Representation: Base-2 positional, two's complement. 3.3. Floating Point (float32, float64) Representation: [IEEE754]. 3.4. Character (char8, char16, char32) Representation: Base-2 positional, unsigned. Reference to codepoint within charset selected by context. 3.5. Multi-Byte Character (mb8, mb16) Representation: Depends on selected charset. Type mb8 can be used with UTF-7 and UTF-8. Type mb16 can be used with UTF-16. Other multi-byte charsets are handled in a similar manner. 3.6. Binary-Coded Decimal (bcd4, bcd8) Representation bcd4: {0000..1001, 1100, 1101} => {0..9, +, -} All others undefined Representation bcd8: Depends on selected charset (ASCII family or EBCDIC family) {'0'..'9', '+', '-'} => {0..9, +, -} All others undefined 3.7. Void (void) Representation: N/A. Eberle Expires June 2007 [Page 4] Internet Draft Standard Data Types December 2006 4. Context Details A data type is not valid until all of its references to the context have been established. For example, uint32 requires the byte-order from the context. Likewise, char8 requires the charset from the context. There are many ways to establish context values. They can be written to a file header, negotiated at runtime, specified in an architecture document, etc. This document does not specify the mechanism. It only defines the various dependencies. 4.1. Byte-Order Byte-order is the order in which to store a series of bytes. It can either be most-to-least significant, or least-to-most significant. The former is called big-endian, the latter is called little-endian. 4.2. Charset The charset defines the set of codepoints that a given character value can point to. The set of valid charsets is defined in the IANA Charset MIB file [RFC3808]. Note, not all charsets can be used with all character data types. For example, charset ISO-10646-UCS-2 cannot be used with type char8. Therefore, the user of these types must make informed charset/data type pairings. Eberle Expires June 2007 [Page 5] Internet Draft Standard Data Types December 2006 5. Security Considerations This document contains no security considerations. 6. IANA Considerations The author recommends that the IANA create a registry to record the data type names and identifiers described in this document. 7. References 7.1. Normative References [IEEE754] IEEE Std 754-1985, IEEE Standard for Binary Floating-Point Arithmetic. [RFC3808] McDonald, I., "IANA Charset MIB", Informational, RFC 3808, June 2004. 7.2. Informative References [CHARSET] IANA Charset Registry (archived at): http://www.iana.org/assignments/character-sets Author's Address Jim Eberle 1450 Lincoln Ave, Unit 9 Burlingame, CA 94010 EMail: jim.eberle@fastnlight.com Eberle Expires June 2007 [Page 6] Internet Draft Standard Data Types December 2006 Full Copyright Statement Copyright (C) The IETF Trust (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Eberle Expires June 2007 [Page 7]