Namespace: go.std.encoding.asn1

v1.0

Contents

• Summary
• Index
• Constants
• Variables
• Functions, Macros, and Special Forms
• Types

Summary

Provides a low-level interface to the encoding/asn1 package.

Package asn1 implements parsing of DER-encoded ASN.1 data structures,
as defined in ITU-T Rec X.690.

See also ``A Layman's Guide to a Subset of ASN.1, BER, and DER,''
http://luca.ntop.org/Teaching/Appunti/asn1.html.

Index

• *BitString
• *Enumerated
• *Flag
• *ObjectIdentifier
• *RawContent
• *RawValue
• *StructuralError
• *SyntaxError
• BitString
• ClassApplication
• ClassContextSpecific
• ClassPrivate
• ClassUniversal
• Enumerated
• Flag
• Marshal
• MarshalWithParams
• NullBytes
• NullRawValue
• ObjectIdentifier
• RawContent
• RawValue
• StructuralError
• SyntaxError
• TagBMPString
• TagBitString
• TagBoolean
• TagEnum
• TagGeneralString
• TagGeneralizedTime
• TagIA5String
• TagInteger
• TagNull
• TagNumericString
• TagOID
• TagOctetString
• TagPrintableString
• TagSequence
• TagSet
• TagT61String
• TagUTCTime
• TagUTF8String
• Unmarshal
• UnmarshalWithParams
• arrayOfBitString
• arrayOfEnumerated
• arrayOfFlag
• arrayOfObjectIdentifier
• arrayOfRawContent
• arrayOfRawValue
• arrayOfStructuralError
• arrayOfSyntaxError

Legend

Constant Variable Function Macro Special form Type GoVar Receiver/Method

Constants

Constants are variables with :const true in their metadata. Joker currently does not recognize them as special; as such, it allows redefining them or their values.

• ClassApplication

  Int v1.0

  ASN.1 class types represent the namespace of the tag.
  

• ClassContextSpecific

  Int v1.0

  ASN.1 class types represent the namespace of the tag.
  

• ClassPrivate

  Int v1.0

  ASN.1 class types represent the namespace of the tag.
  

• ClassUniversal

  Int v1.0

  ASN.1 class types represent the namespace of the tag.
  

• TagBMPString

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagBitString

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagBoolean

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagEnum

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagGeneralString

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagGeneralizedTime

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagIA5String

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagInteger

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagNull

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagNumericString

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagOID

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagOctetString

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagPrintableString

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagSequence

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagSet

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagT61String

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagUTCTime

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

• TagUTF8String

  Int v1.0

  ASN.1 tags represent the type of the following object.
  

Variables

• NullBytes

  Var v1.0

  NullBytes contains bytes representing the DER-encoded ASN.1 NULL type.
  

• NullRawValue

  Var v1.0

  NullRawValue is a RawValue with its Tag set to the ASN.1 NULL type tag (5).
  

Functions, Macros, and Special Forms

• Marshal

  Function v1.0

  (Marshal val)
  

  Marshal returns the ASN.1 encoding of val.
  
  In addition to the struct tags recognised by Unmarshal, the following can be
  used:
  
  ia5: causes strings to be marshaled as ASN.1, IA5String values
  omitempty: causes empty slices to be skipped
  printable: causes strings to be marshaled as ASN.1, PrintableString values
  utf8: causes strings to be marshaled as ASN.1, UTF8String values
  utc: causes time.Time to be marshaled as ASN.1, UTCTime values
  generalized: causes time.Time to be marshaled as ASN.1, GeneralizedTime values
  
  Go input arguments: (val any)
  
  Go returns: ([]byte, error)
  
  Joker input arguments: [^GoObject val]
  
  Joker returns: [^arrayOfByte, ^Error]

• MarshalWithParams

  Function v1.0

  (MarshalWithParams val params)
  

  MarshalWithParams allows field parameters to be specified for the
  top-level element. The form of the params is the same as the field tags.
  
  Go input arguments: (val any, params string)
  
  Go returns: ([]byte, error)
  
  Joker input arguments: [^GoObject val, ^String params]
  
  Joker returns: [^arrayOfByte, ^Error]

• Unmarshal

  Function v1.0

  (Unmarshal b val)
  

  Unmarshal parses the DER-encoded ASN.1 data structure b
  and uses the reflect package to fill in an arbitrary value pointed at by val.
  Because Unmarshal uses the reflect package, the structs
  being written to must use upper case field names. If val
  is nil or not a pointer, Unmarshal returns an error.
  
  After parsing b, any bytes that were leftover and not used to fill
  val will be returned in rest. When parsing a SEQUENCE into a struct,
  any trailing elements of the SEQUENCE that do not have matching
  fields in val will not be included in rest, as these are considered
  valid elements of the SEQUENCE and not trailing data.
  
  An ASN.1 INTEGER can be written to an int, int32, int64,
  or *big.Int (from the math/big package).
  If the encoded value does not fit in the Go type,
  Unmarshal returns a parse error.
  
  An ASN.1 BIT STRING can be written to a BitString.
  
  An ASN.1 OCTET STRING can be written to a []byte.
  
  An ASN.1 OBJECT IDENTIFIER can be written to an
  ObjectIdentifier.
  
  An ASN.1 ENUMERATED can be written to an Enumerated.
  
  An ASN.1 UTCTIME or GENERALIZEDTIME can be written to a time.Time.
  
  An ASN.1 PrintableString, IA5String, or NumericString can be written to a string.
  
  Any of the above ASN.1 values can be written to an interface{}.
  The value stored in the interface has the corresponding Go type.
  For integers, that type is int64.
  
  An ASN.1 SEQUENCE OF x or SET OF x can be written
  to a slice if an x can be written to the slice's element type.
  
  An ASN.1 SEQUENCE or SET can be written to a struct
  if each of the elements in the sequence can be
  written to the corresponding element in the struct.
  
  The following tags on struct fields have special meaning to Unmarshal:
  
  application specifies that an APPLICATION tag is used
  private specifies that a PRIVATE tag is used
  default:x sets the default value for optional integer fields (only used if optional is also present)
  explicit specifies that an additional, explicit tag wraps the implicit one
  optional marks the field as ASN.1 OPTIONAL
  set causes a SET, rather than a SEQUENCE type to be expected
  tag:x specifies the ASN.1 tag number; implies ASN.1 CONTEXT SPECIFIC
  
  When decoding an ASN.1 value with an IMPLICIT tag into a string field,
  Unmarshal will default to a PrintableString, which doesn't support
  characters such as '@' and '&'. To force other encodings, use the following
  tags:
  
  ia5 causes strings to be unmarshaled as ASN.1 IA5String values
  numeric causes strings to be unmarshaled as ASN.1 NumericString values
  utf8 causes strings to be unmarshaled as ASN.1 UTF8String values
  
  If the type of the first field of a structure is RawContent then the raw
  ASN1 contents of the struct will be stored in it.
  
  If the name of a slice type ends with "SET" then it's treated as if
  the "set" tag was set on it. This results in interpreting the type as a
  SET OF x rather than a SEQUENCE OF x. This can be used with nested slices
  where a struct tag cannot be given.
  
  Other ASN.1 types are not supported; if it encounters them,
  Unmarshal returns a parse error.
  
  Go input arguments: (b []byte, val any)
  
  Go returns: (rest []byte, err error)
  
  Joker input arguments: [^arrayOfByte b, ^GoObject val]
  
  Joker returns: [^arrayOfByte rest, ^Error err]

• UnmarshalWithParams

  Function v1.0

  (UnmarshalWithParams b val params)
  

  UnmarshalWithParams allows field parameters to be specified for the
  top-level element. The form of the params is the same as the field tags.
  
  Go input arguments: (b []byte, val any, params string)
  
  Go returns: (rest []byte, err error)
  
  Joker input arguments: [^arrayOfByte b, ^GoObject val, ^String params]
  
  Joker returns: [^arrayOfByte rest, ^Error err]

Types

• *BitString

  Concrete Type v1.0

  BitString is the structure to use when you want an ASN.1 BIT STRING type. A
  bit string is padded up to the nearest byte in memory and the number of
  valid bits is recorded. Padding bits will be zero.
  

• *Enumerated

  Concrete Type v1.0

  An Enumerated is represented as a plain int.
  

• *Flag

  Concrete Type v1.0

  A Flag accepts any data and is set to true if present.
  

• *ObjectIdentifier

  Concrete Type v1.0

  An ObjectIdentifier represents an ASN.1 OBJECT IDENTIFIER.
  

• *RawContent

  Concrete Type v1.0

  RawContent is used to signal that the undecoded, DER data needs to be
  preserved for a struct. To use it, the first field of the struct must have
  this type. It's an error for any of the other fields to have this type.
  

• *RawValue

  Concrete Type v1.0

  A RawValue represents an undecoded ASN.1 object.
  

• *StructuralError

  Concrete Type v1.0

  A StructuralError suggests that the ASN.1 data is valid, but the Go type
  which is receiving it doesn't match.
  

• *SyntaxError

  Concrete Type v1.0

  A SyntaxError suggests that the ASN.1 data is invalid.
  

• BitString

  Concrete Type v1.0

  BitString is the structure to use when you want an ASN.1 BIT STRING type. A
  bit string is padded up to the nearest byte in memory and the number of
  valid bits is recorded. Padding bits will be zero.
  

• At

  Receiver for BitString v1.0

  ([i])
  

  At returns the bit at the given index. If the index is out of range it
  returns false.
  

• RightAlign

  Receiver for BitString v1.0

  ([])
  

  RightAlign returns a slice where the padding bits are at the beginning. The
  slice may share memory with the BitString.
  

• Enumerated

  Concrete Type v1.0

  An Enumerated is represented as a plain int.
  

• Flag

  Concrete Type v1.0

  A Flag accepts any data and is set to true if present.
  

• ObjectIdentifier

  Concrete Type v1.0

  An ObjectIdentifier represents an ASN.1 OBJECT IDENTIFIER.
  

• Equal

  Receiver for ObjectIdentifier v1.0

  ([other])
  

  Equal reports whether oi and other represent the same identifier.
  

• String

  Receiver for ObjectIdentifier v1.0

  ([])
  

• RawContent

  Concrete Type v1.0

  RawContent is used to signal that the undecoded, DER data needs to be
  preserved for a struct. To use it, the first field of the struct must have
  this type. It's an error for any of the other fields to have this type.
  

• RawValue

  Concrete Type v1.0

  A RawValue represents an undecoded ASN.1 object.
  

• StructuralError

  Concrete Type v1.0

  A StructuralError suggests that the ASN.1 data is valid, but the Go type
  which is receiving it doesn't match.
  

• Error

  Receiver for StructuralError v1.0

  ([])
  

• SyntaxError

  Concrete Type v1.0

  A SyntaxError suggests that the ASN.1 data is invalid.
  

• Error

  Receiver for SyntaxError v1.0

  ([])
  

• arrayOfBitString

  Concrete Type v1.0

  BitString is the structure to use when you want an ASN.1 BIT STRING type. A
  bit string is padded up to the nearest byte in memory and the number of
  valid bits is recorded. Padding bits will be zero.
  

• arrayOfEnumerated

  Concrete Type v1.0

  An Enumerated is represented as a plain int.
  

• arrayOfFlag

  Concrete Type v1.0

  A Flag accepts any data and is set to true if present.
  

• arrayOfObjectIdentifier

  Concrete Type v1.0

  An ObjectIdentifier represents an ASN.1 OBJECT IDENTIFIER.
  

• arrayOfRawContent

  Concrete Type v1.0

  RawContent is used to signal that the undecoded, DER data needs to be
  preserved for a struct. To use it, the first field of the struct must have
  this type. It's an error for any of the other fields to have this type.
  

• arrayOfRawValue

  Concrete Type v1.0

  A RawValue represents an undecoded ASN.1 object.
  

• arrayOfStructuralError

  Concrete Type v1.0

  A StructuralError suggests that the ASN.1 data is valid, but the Go type
  which is receiving it doesn't match.
  

• arrayOfSyntaxError

  Concrete Type v1.0

  A SyntaxError suggests that the ASN.1 data is invalid.