Source file src/pkg/vendor/golang.org/x/crypto/cryptobyte/asn1/asn1.go

     1	// Copyright 2017 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	// Package asn1 contains supporting types for parsing and building ASN.1
     6	// messages with the cryptobyte package.
     7	package asn1 // import "golang.org/x/crypto/cryptobyte/asn1"
     8	
     9	// Tag represents an ASN.1 identifier octet, consisting of a tag number
    10	// (indicating a type) and class (such as context-specific or constructed).
    11	//
    12	// Methods in the cryptobyte package only support the low-tag-number form, i.e.
    13	// a single identifier octet with bits 7-8 encoding the class and bits 1-6
    14	// encoding the tag number.
    15	type Tag uint8
    16	
    17	const (
    18		classConstructed     = 0x20
    19		classContextSpecific = 0x80
    20	)
    21	
    22	// Constructed returns t with the constructed class bit set.
    23	func (t Tag) Constructed() Tag { return t | classConstructed }
    24	
    25	// ContextSpecific returns t with the context-specific class bit set.
    26	func (t Tag) ContextSpecific() Tag { return t | classContextSpecific }
    27	
    28	// The following is a list of standard tag and class combinations.
    29	const (
    30		BOOLEAN           = Tag(1)
    31		INTEGER           = Tag(2)
    32		BIT_STRING        = Tag(3)
    33		OCTET_STRING      = Tag(4)
    34		NULL              = Tag(5)
    35		OBJECT_IDENTIFIER = Tag(6)
    36		ENUM              = Tag(10)
    37		UTF8String        = Tag(12)
    38		SEQUENCE          = Tag(16 | classConstructed)
    39		SET               = Tag(17 | classConstructed)
    40		PrintableString   = Tag(19)
    41		T61String         = Tag(20)
    42		IA5String         = Tag(22)
    43		UTCTime           = Tag(23)
    44		GeneralizedTime   = Tag(24)
    45		GeneralString     = Tag(27)
    46	)
    47	

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