| // Copyright 2015 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| //go:generate go run gen.go |
| |
| // Package identifier defines the contract between implementations of Encoding |
| // and Index by defining identifiers that uniquely identify standardized coded |
| // character sets (CCS) and character encoding schemes (CES), which we will |
| // together refer to as encodings, for which Encoding implementations provide |
| // converters to and from UTF-8. This package is typically only of concern to |
| // implementers of Indexes and Encodings. |
| // |
| // One part of the identifier is the MIB code, which is defined by IANA and |
| // uniquely identifies a CCS or CES. Each code is associated with data that |
| // references authorities, official documentation as well as aliases and MIME |
| // names. |
| // |
| // Not all CESs are covered by the IANA registry. The "other" string that is |
| // returned by ID can be used to identify other character sets or versions of |
| // existing ones. |
| // |
| // It is recommended that each package that provides a set of Encodings provide |
| // the All and Common variables to reference all supported encodings and |
| // commonly used subset. This allows Index implementations to include all |
| // available encodings without explicitly referencing or knowing about them. |
| package identifier |
| |
| // Note: this package is internal, but could be made public if there is a need |
| // for writing third-party Indexes and Encodings. |
| |
| // References: |
| // - http://source.icu-project.org/repos/icu/icu/trunk/source/data/mappings/convrtrs.txt |
| // - http://www.iana.org/assignments/character-sets/character-sets.xhtml |
| // - http://www.iana.org/assignments/ianacharset-mib/ianacharset-mib |
| // - http://www.ietf.org/rfc/rfc2978.txt |
| // - https://www.unicode.org/reports/tr22/ |
| // - http://www.w3.org/TR/encoding/ |
| // - https://encoding.spec.whatwg.org/ |
| // - https://encoding.spec.whatwg.org/encodings.json |
| // - https://tools.ietf.org/html/rfc6657#section-5 |
| |
| // Interface can be implemented by Encodings to define the CCS or CES for which |
| // it implements conversions. |
| type Interface interface { |
| // ID returns an encoding identifier. Exactly one of the mib and other |
| // values should be non-zero. |
| // |
| // In the usual case it is only necessary to indicate the MIB code. The |
| // other string can be used to specify encodings for which there is no MIB, |
| // such as "x-mac-dingbat". |
| // |
| // The other string may only contain the characters a-z, A-Z, 0-9, - and _. |
| ID() (mib MIB, other string) |
| |
| // NOTE: the restrictions on the encoding are to allow extending the syntax |
| // with additional information such as versions, vendors and other variants. |
| } |
| |
| // A MIB identifies an encoding. It is derived from the IANA MIB codes and adds |
| // some identifiers for some encodings that are not covered by the IANA |
| // standard. |
| // |
| // See http://www.iana.org/assignments/ianacharset-mib. |
| type MIB uint16 |
| |
| // These additional MIB types are not defined in IANA. They are added because |
| // they are common and defined within the text repo. |
| const ( |
| // Unofficial marks the start of encodings not registered by IANA. |
| Unofficial MIB = 10000 + iota |
| |
| // Replacement is the WhatWG replacement encoding. |
| Replacement |
| |
| // XUserDefined is the code for x-user-defined. |
| XUserDefined |
| |
| // MacintoshCyrillic is the code for x-mac-cyrillic. |
| MacintoshCyrillic |
| ) |