Concise Binary Object Representation (CBOR) Tags for Typed Arrays
RFC 8746
Document | Type | RFC - Proposed Standard (February 2020; No errata) | |
---|---|---|---|
Author | Carsten Bormann | ||
Last updated | 2020-02-28 | ||
Replaces | draft-jroatch-cbor-tags | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html xml pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Francesca Palombini | ||
Shepherd write-up | Show (last changed 2019-08-22) | ||
IESG | IESG state | RFC 8746 (Proposed Standard) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Alexey Melnikov | ||
Send notices to | Francesca Palombini <francesca.palombini@ericsson.com> | ||
IANA | IANA review state | IANA OK - Actions Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) C. Bormann, Ed. Request for Comments: 8746 Universität Bremen TZI Category: Standards Track February 2020 ISSN: 2070-1721 Concise Binary Object Representation (CBOR) Tags for Typed Arrays Abstract The Concise Binary Object Representation (CBOR), as defined in RFC 7049, is a data format whose design goals include the possibility of extremely small code size, fairly small message size, and extensibility without the need for version negotiation. This document makes use of this extensibility to define a number of CBOR tags for typed arrays of numeric data, as well as additional tags for multi-dimensional and homogeneous arrays. It is intended as the reference document for the IANA registration of the CBOR tags defined. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8746. Copyright Notice Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction 1.1. Terminology 2. Typed Arrays 2.1. Types of Numbers 3. Additional Array Tags 3.1. Multi-dimensional Array 3.1.1. Row-Major Order 3.1.2. Column-Major Order 3.2. Homogeneous Array 4. Discussion 5. CDDL Typenames 6. IANA Considerations 7. Security Considerations 8. References 8.1. Normative References 8.2. Informative References Acknowledgements Contributors Author's Address 1. Introduction The Concise Binary Object Representation (CBOR) [RFC7049] provides for the interchange of structured data without a requirement for a pre-agreed schema. [RFC7049] defines a basic set of data types as well as a tagging mechanism that enables extending the set of data types supported via an IANA registry. Recently, a simple form of typed arrays of numeric data has received interest both in the Web graphics community [TypedArray] and in the JavaScript specification (see Section 22.2 (https://www.ecma- international.org/ecma-262/10.0/index.html#sec-typedarray-objects) of [ECMA-ES10]) as well as in corresponding implementations [ArrayBuffer]. Since these typed arrays may carry significant amounts of data, there is interest in interchanging them in CBOR without the need of lengthy conversion of each number in the array. This can also save space overhead with encoding a type for each element of an array. This document defines a number of interrelated CBOR tags that cover these typed arrays, as well as additional tags for multi-dimensional and homogeneous arrays. It is intended as the reference document for the IANA registration of the tags defined. Note that an application that generates CBOR with these tags has considerable freedom in choosing variants (e.g., with respect to endianness, embedded type (signed vs. unsigned), and number of bits per element) or whether a tag defined in this specification is used at all instead of more basic CBOR. In contrast to representation variants of single CBOR numbers, there is no representation that could be identified as "preferred". If deterministic encoding is desired in a CBOR-based protocol making use of these tags, the protocol has to define which of the encoding variants are used for each individual case. 1.1. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. The term "byte" is used in its now-customary sense as a synonym for "octet". Where bit arithmetic is explained, this document usesShow full document text