package cryptobyte

Import Path
	vendor/golang.org/x/crypto/cryptobyte (on go.dev)

Dependency Relation
	imports 7 packages, and imported by 3 packages


Involved Source Files

	      asn1.go
	      builder.go
	
		Package cryptobyte contains types that help with parsing and constructing
		length-prefixed, binary messages, including ASN.1 DER. (The asn1 subpackage
		contains useful ASN.1 constants.)

		The String type is for parsing. It wraps a []byte slice and provides helper
		functions for consuming structures, value by value.

		The Builder type is for constructing messages. It providers helper functions
		for appending values and also for appending length-prefixed submessages –
		without having to worry about calculating the length prefix ahead of time.

		See the documentation and examples for the Builder and String types to get
		started.


Package-Level Type Names (total 5, all are exported)


	/* sort exporteds by:  |  */
	
		A Builder builds byte strings from fixed-length and length-prefixed values.
		Builders either allocate space as needed, or are ‘fixed’, which means that
		they write into a given buffer and produce an error if it's exhausted.

		The zero value is a usable Builder that allocates space as needed.

		Simple values are marshaled and appended to a Builder using methods on the
		Builder. Length-prefixed values are marshaled by providing a
		BuilderContinuation, which is a function that writes the inner contents of
		the value to a given Builder. See the documentation for BuilderContinuation
		for details.

		
			
		
			
				AddASN1 appends an ASN.1 object. The object is prefixed with the given tag.
				Tags greater than 30 are not supported and result in an error (i.e.
				low-tag-number form only). The child builder passed to the
				BuilderContinuation can be used to build the content of the ASN.1 object.

			
				AddASN1BigInt appends a DER-encoded ASN.1 INTEGER.

			
				AddASN1BitString appends a DER-encoded ASN.1 BIT STRING. This does not
				support BIT STRINGs that are not a whole number of bytes.

			(*T) AddASN1Boolean(v bool)
			
				AddASN1Enum appends a DER-encoded ASN.1 ENUMERATION.

			
				AddASN1GeneralizedTime appends a DER-encoded ASN.1 GENERALIZEDTIME.

			
				AddASN1Int64 appends a DER-encoded ASN.1 INTEGER.

			
				AddASN1Int64WithTag appends a DER-encoded ASN.1 INTEGER with the
				given tag.

			(*T) AddASN1NULL()
			(*T) AddASN1ObjectIdentifier(oid encoding_asn1.ObjectIdentifier)
			
				AddASN1OctetString appends a DER-encoded ASN.1 OCTET STRING.

			
				AddASN1Uint64 appends a DER-encoded ASN.1 INTEGER.

			
				AddBytes appends a sequence of bytes to the byte string.

			
				AddUint16 appends a big-endian, 16-bit value to the byte string.

			
				AddUint16LengthPrefixed adds a big-endian, 16-bit length-prefixed byte sequence.

			
				AddUint24 appends a big-endian, 24-bit value to the byte string. The highest
				byte of the 32-bit input value is silently truncated.

			
				AddUint24LengthPrefixed adds a big-endian, 24-bit length-prefixed byte sequence.

			
				AddUint32 appends a big-endian, 32-bit value to the byte string.

			
				AddUint32LengthPrefixed adds a big-endian, 32-bit length-prefixed byte sequence.

			
				AddUint8 appends an 8-bit value to the byte string.

			
				AddUint8LengthPrefixed adds a 8-bit length-prefixed byte sequence.

			
				AddValue calls Marshal on v, passing a pointer to the builder to append to.
				If Marshal returns an error, it is set on the Builder so that subsequent
				appends don't have an effect.

			
				Bytes returns the bytes written by the builder or an error if one has
				occurred during building.

			
				BytesOrPanic returns the bytes written by the builder or panics if an error
				has occurred during building.

			
				MarshalASN1 calls encoding_asn1.Marshal on its input and appends the result if
				successful or records an error if one occurred.

			
				SetError sets the value to be returned as the error from Bytes. Writes
				performed after calling SetError are ignored.

			
				Unwrite rolls back n bytes written directly to the Builder. An attempt by a
				child builder passed to a continuation to unwrite bytes from its parent will
				panic.

			
		
			func NewBuilder(buffer []byte) *Builder
			func NewFixedBuilder(buffer []byte) *Builder
		
			func MarshalingValue.Marshal(b *Builder) error
			


	
		BuilderContinuation is a continuation-passing interface for building
		length-prefixed byte sequences. Builder methods for length-prefixed
		sequences (AddUint8LengthPrefixed etc) will invoke the BuilderContinuation
		supplied to them. The child builder passed to the continuation can be used
		to build the content of the length-prefixed sequence. For example:

		  parent := cryptobyte.NewBuilder()
		  parent.AddUint8LengthPrefixed(func (child *Builder) {
		    child.AddUint8(42)
		    child.AddUint8LengthPrefixed(func (grandchild *Builder) {
		      grandchild.AddUint8(5)
		    })
		  })

		It is an error to write more bytes to the child than allowed by the reserved
		length prefix. After the continuation returns, the child must be considered
		invalid, i.e. users must not store any copies or references of the child
		that outlive the continuation.

		If the continuation panics with a value of type BuildError then the inner
		error will be returned as the error from Bytes. If the child panics
		otherwise then Bytes will repanic with the same value.

		
			func (*Builder).AddASN1(tag asn1.Tag, f BuilderContinuation)
			func (*Builder).AddUint16LengthPrefixed(f BuilderContinuation)
			func (*Builder).AddUint24LengthPrefixed(f BuilderContinuation)
			func (*Builder).AddUint32LengthPrefixed(f BuilderContinuation)
			func (*Builder).AddUint8LengthPrefixed(f BuilderContinuation)
			


	
		BuildError wraps an error. If a BuilderContinuation panics with this value,
		the panic will be recovered and the inner error will be returned from
		Builder.Bytes.

		
			Err error


	
		A MarshalingValue marshals itself into a Builder.

		
			
				Marshal is called by Builder.AddValue. It receives a pointer to a builder
				to marshal itself into. It may return an error that occurred during
				marshaling, such as unset or invalid values.

		
			
		
			func (*Builder).AddValue(v MarshalingValue)


	
		String represents a string of bytes. It provides methods for parsing
		fixed-length and length-prefixed values from it.

		
			
				CopyBytes copies len(out) bytes into out and advances over them. It reports
				whether the copy operation was successful

			
				Empty reports whether the string does not contain any bytes.

			
				PeekASN1Tag reports whether the next ASN.1 value on the string starts with
				the given tag.

			
				ReadASN1 reads the contents of a DER-encoded ASN.1 element (not including
				tag and length bytes) into out, and advances. The element must match the
				given tag. It reports whether the read was successful.

				Tags greater than 30 are not supported (i.e. low-tag-number format only).

			
				ReadASN1BitString decodes an ASN.1 BIT STRING into out and advances.
				It reports whether the read was successful.

			
				ReadASN1BitString decodes an ASN.1 BIT STRING into out and advances. It is
				an error if the BIT STRING is not a whole number of bytes. It reports
				whether the read was successful.

			
				ReadASN1Boolean decodes an ASN.1 BOOLEAN and converts it to a boolean
				representation into out and advances. It reports whether the read
				was successful.

			
				ReadASN1Bytes reads the contents of a DER-encoded ASN.1 element (not including
				tag and length bytes) into out, and advances. The element must match the
				given tag. It reports whether the read was successful.

			
				ReadASN1Element reads the contents of a DER-encoded ASN.1 element (including
				tag and length bytes) into out, and advances. The element must match the
				given tag. It reports whether the read was successful.

				Tags greater than 30 are not supported (i.e. low-tag-number format only).

			
				ReadASN1Enum decodes an ASN.1 ENUMERATION into out and advances. It reports
				whether the read was successful.

			
				ReadASN1GeneralizedTime decodes an ASN.1 GENERALIZEDTIME into out and
				advances. It reports whether the read was successful.

			
				ReadASN1Int64WithTag decodes an ASN.1 INTEGER with the given tag into out
				and advances. It reports whether the read was successful and resulted in a
				value that can be represented in an int64.

			
				ReadASN1Integer decodes an ASN.1 INTEGER into out and advances. If out does
				not point to an integer or to a big.Int, it panics. It reports whether the
				read was successful.

			
				ReadASN1ObjectIdentifier decodes an ASN.1 OBJECT IDENTIFIER into out and
				advances. It reports whether the read was successful.

			
				ReadAnyASN1 reads the contents of a DER-encoded ASN.1 element (not including
				tag and length bytes) into out, sets outTag to its tag, and advances.
				It reports whether the read was successful.

				Tags greater than 30 are not supported (i.e. low-tag-number format only).

			
				ReadAnyASN1Element reads the contents of a DER-encoded ASN.1 element
				(including tag and length bytes) into out, sets outTag to is tag, and
				advances. It reports whether the read was successful.

				Tags greater than 30 are not supported (i.e. low-tag-number format only).

			
				ReadBytes reads n bytes into out and advances over them. It reports
				whether the read was successful.

			
				ReadOptionalASN1 attempts to read the contents of a DER-encoded ASN.1
				element (not including tag and length bytes) tagged with the given tag into
				out. It stores whether an element with the tag was found in outPresent,
				unless outPresent is nil. It reports whether the read was successful.

			
				ReadOptionalASN1Boolean sets *out to the value of the next ASN.1 BOOLEAN or,
				if the next bytes are not an ASN.1 BOOLEAN, to the value of defaultValue.
				It reports whether the operation was successful.

			
				ReadOptionalASN1Integer attempts to read an optional ASN.1 INTEGER
				explicitly tagged with tag into out and advances. If no element with a
				matching tag is present, it writes defaultValue into out instead. If out
				does not point to an integer or to a big.Int, it panics. It reports
				whether the read was successful.

			
				ReadOptionalASN1OctetString attempts to read an optional ASN.1 OCTET STRING
				explicitly tagged with tag into out and advances. If no element with a
				matching tag is present, it sets "out" to nil instead. It reports
				whether the read was successful.

			
				ReadUint16 decodes a big-endian, 16-bit value into out and advances over it.
				It reports whether the read was successful.

			
				ReadUint16LengthPrefixed reads the content of a big-endian, 16-bit
				length-prefixed value into out and advances over it. It reports whether the
				read was successful.

			
				ReadUint24 decodes a big-endian, 24-bit value into out and advances over it.
				It reports whether the read was successful.

			
				ReadUint24LengthPrefixed reads the content of a big-endian, 24-bit
				length-prefixed value into out and advances over it. It reports whether
				the read was successful.

			
				ReadUint32 decodes a big-endian, 32-bit value into out and advances over it.
				It reports whether the read was successful.

			
				ReadUint8 decodes an 8-bit value into out and advances over it.
				It reports whether the read was successful.

			
				ReadUint8LengthPrefixed reads the content of an 8-bit length-prefixed value
				into out and advances over it. It reports whether the read was successful.

			
				Skip advances the String by n byte and reports whether it was successful.

			
				SkipASN1 reads and discards an ASN.1 element with the given tag. It
				reports whether the operation was successful.

			
				SkipOptionalASN1 advances s over an ASN.1 element with the given tag, or
				else leaves s unchanged. It reports whether the operation was successful.

			
		
			func (*String).ReadAnyASN1(out *String, outTag *asn1.Tag) bool
			func (*String).ReadAnyASN1Element(out *String, outTag *asn1.Tag) bool
			func (*String).ReadASN1(out *String, tag asn1.Tag) bool
			func (*String).ReadASN1Element(out *String, tag asn1.Tag) bool
			func (*String).ReadOptionalASN1(out *String, outPresent *bool, tag asn1.Tag) bool
			func (*String).ReadUint16LengthPrefixed(out *String) bool
			func (*String).ReadUint24LengthPrefixed(out *String) bool
			func (*String).ReadUint8LengthPrefixed(out *String) bool
			




Package-Level Functions (total 6, in which 2 are exported)


	
		NewBuilder creates a Builder that appends its output to the given buffer.
		Like append(), the slice will be reallocated if its capacity is exceeded.
		Use Bytes to get the final buffer.


	
		NewFixedBuilder creates a Builder that appends its output into the given
		buffer. This builder does not reallocate the output buffer. Writes that
		would exceed the buffer's capacity are treated as an error.


	


Package-Level Variables (total 2, neither is exported)

	


Package-Level Constants (only one, which is unexported)