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.
type BuildError struct {
Err error
}
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.
type Builder struct {
// contains filtered or unexported fields
}
func NewBuilder(buffer []byte) *Builder
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.
func NewFixedBuilder(buffer []byte) *Builder
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.
func (b *Builder) AddASN1(tag asn1.Tag, f BuilderContinuation)
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.
func (b *Builder) AddASN1BigInt(n *big.Int)
AddASN1BigInt appends a DER-encoded ASN.1 INTEGER.
func (b *Builder) AddASN1BitString(data []byte)
AddASN1BitString appends a DER-encoded ASN.1 BIT STRING. This does not support BIT STRINGs that are not a whole number of bytes.
func (b *Builder) AddASN1Boolean(v bool)
func (b *Builder) AddASN1Enum(v int64)
AddASN1Enum appends a DER-encoded ASN.1 ENUMERATION.
func (b *Builder) AddASN1GeneralizedTime(t time.Time)
AddASN1GeneralizedTime appends a DER-encoded ASN.1 GENERALIZEDTIME.
func (b *Builder) AddASN1Int64(v int64)
AddASN1Int64 appends a DER-encoded ASN.1 INTEGER.
func (b *Builder) AddASN1Int64WithTag(v int64, tag asn1.Tag)
AddASN1Int64WithTag appends a DER-encoded ASN.1 INTEGER with the given tag.
func (b *Builder) AddASN1NULL()
func (b *Builder) AddASN1ObjectIdentifier(oid encoding_asn1.ObjectIdentifier)
func (b *Builder) AddASN1OctetString(bytes []byte)
AddASN1OctetString appends a DER-encoded ASN.1 OCTET STRING.
func (b *Builder) AddASN1UTCTime(t time.Time)
AddASN1UTCTime appends a DER-encoded ASN.1 UTCTime.
func (b *Builder) AddASN1Uint64(v uint64)
AddASN1Uint64 appends a DER-encoded ASN.1 INTEGER.
func (b *Builder) AddBytes(v []byte)
AddBytes appends a sequence of bytes to the byte string.
func (b *Builder) AddUint16(v uint16)
AddUint16 appends a big-endian, 16-bit value to the byte string.
func (b *Builder) AddUint16LengthPrefixed(f BuilderContinuation)
AddUint16LengthPrefixed adds a big-endian, 16-bit length-prefixed byte sequence.
func (b *Builder) AddUint24(v uint32)
AddUint24 appends a big-endian, 24-bit value to the byte string. The highest byte of the 32-bit input value is silently truncated.
func (b *Builder) AddUint24LengthPrefixed(f BuilderContinuation)
AddUint24LengthPrefixed adds a big-endian, 24-bit length-prefixed byte sequence.
func (b *Builder) AddUint32(v uint32)
AddUint32 appends a big-endian, 32-bit value to the byte string.
func (b *Builder) AddUint32LengthPrefixed(f BuilderContinuation)
AddUint32LengthPrefixed adds a big-endian, 32-bit length-prefixed byte sequence.
func (b *Builder) AddUint48(v uint64)
AddUint48 appends a big-endian, 48-bit value to the byte string.
func (b *Builder) AddUint64(v uint64)
AddUint64 appends a big-endian, 64-bit value to the byte string.
func (b *Builder) AddUint8(v uint8)
AddUint8 appends an 8-bit value to the byte string.
func (b *Builder) AddUint8LengthPrefixed(f BuilderContinuation)
AddUint8LengthPrefixed adds a 8-bit length-prefixed byte sequence.
func (b *Builder) AddValue(v MarshalingValue)
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.
func (b *Builder) Bytes() ([]byte, error)
Bytes returns the bytes written by the builder or an error if one has occurred during building.
func (b *Builder) BytesOrPanic() []byte
BytesOrPanic returns the bytes written by the builder or panics if an error has occurred during building.
func (b *Builder) MarshalASN1(v interface{})
MarshalASN1 calls encoding_asn1.Marshal on its input and appends the result if successful or records an error if one occurred.
func (b *Builder) SetError(err error)
SetError sets the value to be returned as the error from Bytes. Writes performed after calling SetError are ignored.
func (b *Builder) Unwrite(n int)
Unwrite rolls back non-negative 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.
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.
type BuilderContinuation func(child *Builder)
A MarshalingValue marshals itself into a Builder.
type MarshalingValue interface {
// 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.
Marshal(b *Builder) error
}
String represents a string of bytes. It provides methods for parsing fixed-length and length-prefixed values from it.
type String []byte
func (s *String) CopyBytes(out []byte) bool
CopyBytes copies len(out) bytes into out and advances over them. It reports whether the copy operation was successful
func (s String) Empty() bool
Empty reports whether the string does not contain any bytes.
func (s String) PeekASN1Tag(tag asn1.Tag) bool
PeekASN1Tag reports whether the next ASN.1 value on the string starts with the given tag.
func (s *String) ReadASN1(out *String, tag asn1.Tag) bool
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).
func (s *String) ReadASN1BitString(out *encoding_asn1.BitString) bool
ReadASN1BitString decodes an ASN.1 BIT STRING into out and advances. It reports whether the read was successful.
func (s *String) ReadASN1BitStringAsBytes(out *[]byte) bool
ReadASN1BitStringAsBytes 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.
func (s *String) ReadASN1Boolean(out *bool) bool
ReadASN1Boolean decodes an ASN.1 BOOLEAN and converts it to a boolean representation into out and advances. It reports whether the read was successful.
func (s *String) ReadASN1Bytes(out *[]byte, tag asn1.Tag) bool
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.
func (s *String) ReadASN1Element(out *String, tag asn1.Tag) bool
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).
func (s *String) ReadASN1Enum(out *int) bool
ReadASN1Enum decodes an ASN.1 ENUMERATION into out and advances. It reports whether the read was successful.
func (s *String) ReadASN1GeneralizedTime(out *time.Time) bool
ReadASN1GeneralizedTime decodes an ASN.1 GENERALIZEDTIME into out and advances. It reports whether the read was successful.
func (s *String) ReadASN1Int64WithTag(out *int64, tag asn1.Tag) bool
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.
func (s *String) ReadASN1Integer(out interface{}) bool
ReadASN1Integer decodes an ASN.1 INTEGER into out and advances. If out does not point to an integer, to a big.Int, or to a []byte it panics. Only positive and zero values can be decoded into []byte, and they are returned as big-endian binary values that share memory with s. Positive values will have no leading zeroes, and zero will be returned as a single zero byte. ReadASN1Integer reports whether the read was successful.
func (s *String) ReadASN1ObjectIdentifier(out *encoding_asn1.ObjectIdentifier) bool
ReadASN1ObjectIdentifier decodes an ASN.1 OBJECT IDENTIFIER into out and advances. It reports whether the read was successful.
func (s *String) ReadASN1UTCTime(out *time.Time) bool
ReadASN1UTCTime decodes an ASN.1 UTCTime into out and advances. It reports whether the read was successful.
func (s *String) ReadAnyASN1(out *String, outTag *asn1.Tag) bool
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).
func (s *String) ReadAnyASN1Element(out *String, outTag *asn1.Tag) bool
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).
func (s *String) ReadBytes(out *[]byte, n int) bool
ReadBytes reads n bytes into out and advances over them. It reports whether the read was successful.
func (s *String) ReadOptionalASN1(out *String, outPresent *bool, tag asn1.Tag) bool
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.
func (s *String) ReadOptionalASN1Boolean(out *bool, tag asn1.Tag, defaultValue bool) bool
ReadOptionalASN1Boolean attempts to read an optional ASN.1 BOOLEAN explicitly tagged with tag into out and advances. If no element with a matching tag is present, it sets "out" to defaultValue instead. It reports whether the read was successful.
func (s *String) ReadOptionalASN1Integer(out interface{}, tag asn1.Tag, defaultValue interface{}) bool
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. Otherwise, it behaves like ReadASN1Integer.
func (s *String) ReadOptionalASN1OctetString(out *[]byte, outPresent *bool, tag asn1.Tag) bool
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.
func (s *String) ReadUint16(out *uint16) bool
ReadUint16 decodes a big-endian, 16-bit value into out and advances over it. It reports whether the read was successful.
func (s *String) ReadUint16LengthPrefixed(out *String) bool
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.
func (s *String) ReadUint24(out *uint32) bool
ReadUint24 decodes a big-endian, 24-bit value into out and advances over it. It reports whether the read was successful.
func (s *String) ReadUint24LengthPrefixed(out *String) bool
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.
func (s *String) ReadUint32(out *uint32) bool
ReadUint32 decodes a big-endian, 32-bit value into out and advances over it. It reports whether the read was successful.
func (s *String) ReadUint48(out *uint64) bool
ReadUint48 decodes a big-endian, 48-bit value into out and advances over it. It reports whether the read was successful.
func (s *String) ReadUint64(out *uint64) bool
ReadUint64 decodes a big-endian, 64-bit value into out and advances over it. It reports whether the read was successful.
func (s *String) ReadUint8(out *uint8) bool
ReadUint8 decodes an 8-bit value into out and advances over it. It reports whether the read was successful.
func (s *String) ReadUint8LengthPrefixed(out *String) bool
ReadUint8LengthPrefixed reads the content of an 8-bit length-prefixed value into out and advances over it. It reports whether the read was successful.
func (s *String) Skip(n int) bool
Skip advances the String by n byte and reports whether it was successful.
func (s *String) SkipASN1(tag asn1.Tag) bool
SkipASN1 reads and discards an ASN.1 element with the given tag. It reports whether the operation was successful.
func (s *String) SkipOptionalASN1(tag asn1.Tag) bool
SkipOptionalASN1 advances s over an ASN.1 element with the given tag, or else leaves s unchanged. It reports whether the operation was successful.
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