scodec-core
2.2.1
API
Generated with
scodec-core/scodec.codecs/DiscriminatorCodec

DiscriminatorCodec

scodec.codecs.DiscriminatorCodec
final class DiscriminatorCodec[A, B] extends Codec[A] with KnownDiscriminatorType[B]

Codec that supports the binary structure tag ++ value where the tag identifies the encoding/decoding of the value.

To build an instance of this codec, call discriminated and specify the tag type via the by method. Then call one more more of the case combinators on this class.

The most general case combinators are caseO and caseP. In addition to a tag, the caseO combinator is defined by providing a mapping from A to Option[R], a mapping from R to A, and a Codec[R]. The case is used for encoding if the mapping from A to Option[R] returns a Some and it is used for decoding upon matching the tag value. The caseP combinators work the same but take a PartialFunction[A, R] instead of an A => Option[R].

If R is a subtype of A, then the mapping from R to A can be omitted. Hence, the subcaseO and subcaseP constrain R to being a subtype of A and do not take a R => A function.

Finally, the least generic case combinators are the typecase combinators which add further constraints to the subcase* combinators. Specifically, the typecase operators omit the A => Option[R] or PartialFunction[A, R] in favor of doing subtype checks. For example, the following codec is a Codec[AnyVal] that encodes a 0 if passed a Boolean and a 1 if passed an Int:

 discriminated[AnyVal].by(uint8).typecase(0, bool).typecase(1, int32)

Often, the values are size-delimited -- that is, there is a size field after the tag field and beforethevaluefield. To support this, use theframingmethod to provide a transformation to each value codec. For example,framing(new CodecTransformation { def apply[X](c: Codec[X]) = variableSizeBytes(uint8, c) })`.

Attributes

by

codec that encodec/decodes the tag value

cases

cases, ordered from highest priority to lowest priority, that handle subsets of A

See also:
Source:
DiscriminatorCodec.scala
Graph
Supertypes
trait Codec[A]
trait Decoder[A]
trait Encoder[A]
class Object
trait Matchable
class Any

Members list

Concise view

Type members

Inherited classlikes

case class UnknownDiscriminator(discriminator: D, context: List[String]) extends Err

Error raised when an unknown discriminator is encountered when decoding.

Error raised when an unknown discriminator is encountered when decoding.

Attributes

Inherited from:
KnownDiscriminatorType
Source:
KnownDiscriminatorType.scala
Graph
Supertypes
trait Product
trait Equals
trait Err
class Object
trait Matchable
class Any

Value members

Concrete methods

def caseO[R](tag: B)(toRep: A => Option[R])(fromRep: R => A)(cr: Codec[R]): DiscriminatorCodec[A, B]

Returns a new discriminator codec with a new case added for the specified tag.

Returns a new discriminator codec with a new case added for the specified tag.

Attributes

R

representative type that this case handles

cr

codec that encodes/decodes Rs

fromRep

function used during decoding that converts an R to an A

tag

tag value for this case

toRep

function used during encoding that converts an A to an Option[R]

Source:
DiscriminatorCodec.scala
def caseP[R](tag: B)(toRep: PartialFunction[A, R])(fromRep: R => A)(cr: Codec[R]): DiscriminatorCodec[A, B]

Returns a new discriminator codec with a new case added for the specified tag.

Returns a new discriminator codec with a new case added for the specified tag.

Attributes

R

representative type that this case handles

cr

codec that encodes/decodes Rs

fromRep

function used during decoding that converts an R to an A

tag

tag value for this case

toRep

partial function from A to R used during encoding

Source:
DiscriminatorCodec.scala
def decode(bits: BitVector): Attempt[DecodeResult[A]]

Attempts to decode a value of type A from the specified bit vector.

Attempts to decode a value of type A from the specified bit vector.

Attributes

bits

bits to decode

Returns:

error if value could not be decoded or the remaining bits and the decoded value

Source:
DiscriminatorCodec.scala
def encode(a: A): Attempt[BitVector]

Attempts to encode the specified value in to a bit vector.

Attempts to encode the specified value in to a bit vector.

Attributes

value

value to encode

Returns:

error or binary encoding of the value

Source:
DiscriminatorCodec.scala
def framing(framing: [x] => (x$1: Codec[x]) => Codec[x]): DiscriminatorCodec[A, B]

Replaces the current framing logic with the specified codec transformation.

Replaces the current framing logic with the specified codec transformation.

Every representative codec is wrapped with the framing logic when encoding/decoding.

Attributes

framing

new framing logic

Source:
DiscriminatorCodec.scala
def singleton[R <: A](tag: B, value: R): DiscriminatorCodec[A, B]

Attributes

Source:
DiscriminatorCodec.scala
def sizeBound: SizeBound

Provides a bound on the size of successfully encoded values.

Provides a bound on the size of successfully encoded values.

Attributes

Source:
DiscriminatorCodec.scala
def subcaseO[R <: A](tag: B)(toRep: A => Option[R])(cr: Codec[R]): DiscriminatorCodec[A, B]

Returns a new discriminator codec with a new case added for the specified tag.

Returns a new discriminator codec with a new case added for the specified tag.

Attributes

R

representative type that this case handles

cr

codec that encodes/decodes Rs

tag

tag value for this case

toRep

function used during encoding that converts an A to an Option[R]

Source:
DiscriminatorCodec.scala
def subcaseP[R <: A](tag: B)(toRep: PartialFunction[A, R])(cr: Codec[R]): DiscriminatorCodec[A, B]

Returns a new discriminator codec with a new case added for the specified tag.

Returns a new discriminator codec with a new case added for the specified tag.

Attributes

R

representative type that this case handles

cr

codec that encodes/decodes Rs

tag

tag value for this case

toRep

partial function from A to R used during encoding

Source:
DiscriminatorCodec.scala
override def toString: String

Returns a string representation of the object.

Returns a string representation of the object.

The default representation is platform dependent.

Attributes

Returns:

a string representation of the object.

Definition Classes
Any
Source:
DiscriminatorCodec.scala
def typecase[R <: A](tag: B, cr: Codec[R])(using evidence$1: ClassTag[R]): DiscriminatorCodec[A, B]

Returns a new discriminator codec with a new case added for the specified tag.

Returns a new discriminator codec with a new case added for the specified tag.

Note: when encoding a value of A, this combinator compares the runtime class of that value to the runtime class of the supplied ClassTag[R]. As such, the erased type of A is used and hence, this operation is not safe to use with parameterized representation types.

Attributes

R

representative type that this case handles

cr

codec that encodes/decodes Rs

tag

tag value for this case

Source:
DiscriminatorCodec.scala

Inherited methods

final def <~[B](codecB: Codec[B])(using Unit =:= B): Codec[A]

Assuming B is Unit, creates a Codec[A] that: encodes the A followed by a unit; decodes an A followed by a unit and discards the decoded unit.

Assuming B is Unit, creates a Codec[A] that: encodes the A followed by a unit; decodes an A followed by a unit and discards the decoded unit.

Operator alias of dropRight.

Attributes

Inherited from:
Codec
Source:
Codec.scala
final def >>~[B](f: A => Codec[B]): Codec[(A, B)]

Returns a new codec that encodes/decodes a value of type (A, B) where the codec of B is dependent on A. Operator alias for flatZip.

Returns a new codec that encodes/decodes a value of type (A, B) where the codec of B is dependent on A. Operator alias for flatZip.

Attributes

Inherited from:
Codec
Source:
Codec.scala
def as[B](using iso: Iso[A, B]): Codec[B]

Transforms this codec to a Codec[B] if A is isomorphic to B.

Transforms this codec to a Codec[B] if A is isomorphic to B.

This is most commonly used to convert a tuple codec to a case class:

Attributes

Example:
case class Point(x: Int, y: Int, z: Int)
val c: Codec[(Int, Int, Int)] = int8 :: int8 :: int8
val p: Codec[Point] = c.as[Point]
Inherited from:
Codec
Source:
Codec.scala
def asDecoder: Decoder[A]

Gets this as a Decoder.

Gets this as a Decoder.

Attributes

Inherited from:
Decoder
Source:
Decoder.scala
def asEncoder: Encoder[A]

Gets this as an Encoder.

Gets this as an Encoder.

Attributes

Inherited from:
Encoder
Source:
Encoder.scala
def collect[F[_], A2 >: A](buffer: BitVector, limit: Option[Int])(using factory: Factory[A2, F[A2]]): Attempt[DecodeResult[F[A2]]]

Repeatedly decodes values of type A from the specified vector and returns a collection of the specified type. Terminates when no more bits are available in the vector or when limit is defined and that many records have been decoded. Exits upon first decoding error.

Repeatedly decodes values of type A from the specified vector and returns a collection of the specified type. Terminates when no more bits are available in the vector or when limit is defined and that many records have been decoded. Exits upon first decoding error.

Attributes

Inherited from:
Decoder
Source:
Decoder.scala
final override def compact: Codec[A]

Converts this encoder to a new encoder that compacts the generated bit vector before returning it

Converts this encoder to a new encoder that compacts the generated bit vector before returning it

Attributes

Definition Classes
Inherited from:
Codec
Source:
Codec.scala
final override def complete: Codec[A]

Converts this decoder to a new decoder that fails decoding if there are remaining bits.

Converts this decoder to a new decoder that fails decoding if there are remaining bits.

Attributes

Definition Classes
Inherited from:
Codec
Source:
Codec.scala
final def consume[B](f: A => Codec[B])(g: B => A): Codec[B]

Similar to flatZip except the A type is not visible in the resulting type -- the binary effects of the Codec[A] still occur though.

Similar to flatZip except the A type is not visible in the resulting type -- the binary effects of the Codec[A] still occur though.

Example usage:

   case class Flags(x: Boolean, y: Boolean, z: Boolean)
   (bool :: bool :: bool :: ignore(5)).consume { flgs =>
     conditional(flgs.x, uint8) :: conditional(flgs.y, uint8) :: conditional(flgs.z, uint8)
   } {
     case (x, y, z) => Flags(x.isDefined, y.isDefined, z.isDefined) }
   }

Attributes

Inherited from:
Codec
Source:
Codec.scala
def contramap[B](f: B => A): Encoder[B]

Converts this encoder to an Encoder[B] using the supplied B => A.

Converts this encoder to an Encoder[B] using the supplied B => A.

Attributes

Inherited from:
Encoder
Source:
Encoder.scala
final def decodeAll[B](f: A => B)(zero: B, append: (B, B) => B)(buffer: BitVector): (Option[Err], B)

Repeatedly decodes values of type A from the specified vector, converts each value to a B and appends it to an accumulator of type B using the supplied zero value and append function. Terminates when no more bits are available in the vector. Exits upon first decoding error.

Repeatedly decodes values of type A from the specified vector, converts each value to a B and appends it to an accumulator of type B using the supplied zero value and append function. Terminates when no more bits are available in the vector. Exits upon first decoding error.

Attributes

Returns:

tuple consisting of the terminating error if any and the accumulated value

Inherited from:
Decoder
Source:
Decoder.scala
override def decodeOnly[AA >: A]: Codec[AA]

Converts this to a codec that fails encoding with an error.

Converts this to a codec that fails encoding with an error.

Attributes

Definition Classes
Inherited from:
Codec
Source:
Codec.scala
final def decodeValue(bits: BitVector): Attempt[A]

Attempts to decode a value of type A from the specified bit vector and discards the remaining bits.

Attempts to decode a value of type A from the specified bit vector and discards the remaining bits.

Attributes

bits

bits to decode

Returns:

error if value could not be decoded or the decoded value

Inherited from:
Decoder
Source:
Decoder.scala
final def downcast[B <: A](using TypeTest[A, B]): Codec[B]

Safely lifts this codec to a codec of a subtype.

Safely lifts this codec to a codec of a subtype.

When a supertype of B that is not a supertype of A is decoded, an decoding error is returned.

Attributes

Inherited from:
Codec
Source:
Codec.scala
final def dropLeft[B](codecB: Codec[B])(using ev: Unit =:= A): Codec[B]

Assuming A is Unit, creates a Codec[B] that: encodes the unit followed by a B; decodes a unit followed by a B and discards the decoded unit.

Assuming A is Unit, creates a Codec[B] that: encodes the unit followed by a B; decodes a unit followed by a B and discards the decoded unit.

Attributes

Inherited from:
Codec
Source:
Codec.scala
final def dropRight[B](codecB: Codec[B])(using ev: Unit =:= B): Codec[A]

Assuming B is Unit, creates a Codec[A] that: encodes the A followed by a unit; decodes an A followed by a unit and discards the decoded unit.

Assuming B is Unit, creates a Codec[A] that: encodes the A followed by a unit; decodes an A followed by a unit and discards the decoded unit.

Attributes

Inherited from:
Codec
Source:
Codec.scala
def econtramap[B](f: B => Attempt[A]): Encoder[B]

Converts this encoder to an Encoder[B] using the supplied B => Attempt[A].

Converts this encoder to an Encoder[B] using the supplied B => Attempt[A].

Attributes

Inherited from:
Encoder
Source:
Encoder.scala
def emap[B](f: A => Attempt[B]): Decoder[B]

Converts this decoder to a Decoder[B] using the supplied A => Attempt[B].

Converts this decoder to a Decoder[B] using the supplied A => Attempt[B].

Attributes

Inherited from:
Decoder
Source:
Decoder.scala
def encodeAll(as: Iterable[A]): Attempt[BitVector]

Encodes all elements of the specified sequence and concatenates the results, or returns the first encountered error.

Encodes all elements of the specified sequence and concatenates the results, or returns the first encountered error.

Attributes

Inherited from:
Encoder
Source:
Encoder.scala
def encodeOnly: Codec[A]

Converts this to a codec that fails decoding with an error.

Converts this to a codec that fails decoding with an error.

Attributes

Inherited from:
Encoder
Source:
Encoder.scala
final def exmap[B](f: A => Attempt[B], g: B => Attempt[A]): Codec[B]

Transforms using two functions, A => Attempt[B] and B => Attempt[A].

Transforms using two functions, A => Attempt[B] and B => Attempt[A].

Attributes

Inherited from:
Codec
Source:
Codec.scala
def flatMap[B](f: A => Decoder[B]): Decoder[B]

Converts this decoder to a Decoder[B] using the supplied A => Decoder[B].

Converts this decoder to a Decoder[B] using the supplied A => Decoder[B].

Attributes

Inherited from:
Decoder
Source:
Decoder.scala
final def flatZip[B](f: A => Codec[B]): Codec[(A, B)]

Returns a new codec that encodes/decodes a value of type (A, B) where the codec of B is dependent on A.

Returns a new codec that encodes/decodes a value of type (A, B) where the codec of B is dependent on A.

Attributes

Inherited from:
Codec
Source:
Codec.scala
def map[B](f: A => B): Decoder[B]

Converts this decoder to a Decoder[B] using the supplied A => B.

Converts this decoder to a Decoder[B] using the supplied A => B.

Attributes

Inherited from:
Decoder
Source:
Decoder.scala
def pcontramap[B](f: B => Option[A]): Encoder[B]

Converts this encoder to an Encoder[B] using the supplied partial function from B to A. The encoding will fail for any B that f maps to None.

Converts this encoder to an Encoder[B] using the supplied partial function from B to A. The encoding will fail for any B that f maps to None.

Attributes

Inherited from:
Encoder
Source:
Encoder.scala
final def tuple: Codec[A *: EmptyTuple]

Lifts this codec in to a codec of a singleton tuple.

Lifts this codec in to a codec of a singleton tuple.

Attributes

Inherited from:
Codec
Source:
Codec.scala
final def unit(zero: A): Codec[Unit]

Converts this to a Codec[Unit] that encodes using the specified zero value and decodes a unit value when this codec decodes an A successfully.

Converts this to a Codec[Unit] that encodes using the specified zero value and decodes a unit value when this codec decodes an A successfully.

Attributes

Inherited from:
Codec
Source:
Codec.scala
final def upcast[B >: A](using TypeTest[B, A]): Codec[B]

Safely lifts this codec to a codec of a supertype.

Safely lifts this codec to a codec of a supertype.

When a subtype of B that is not a subtype of A is passed to encode, an encoding error is returned.

Attributes

Inherited from:
Codec
Source:
Codec.scala
final def withContext(context: String): Codec[A]

Creates a new codec that is functionally equivalent to this codec but pushes the specified context string in to any errors returned from encode or decode.

Creates a new codec that is functionally equivalent to this codec but pushes the specified context string in to any errors returned from encode or decode.

Attributes

Inherited from:
Codec
Source:
Codec.scala
final def withToString(str: => String): Codec[A]

Creates a new codec that is functionally equivalent to this codec but returns the specified string from toString.

Creates a new codec that is functionally equivalent to this codec but returns the specified string from toString.

Attributes

Inherited from:
Codec
Source:
Codec.scala
final def xmap[B](f: A => B, g: B => A): Codec[B]

Transforms using the isomorphism described by two functions, A => B and B => A.

Transforms using the isomorphism described by two functions, A => B and B => A.

Attributes

Inherited from:
Codec
Source:
Codec.scala
final def ~>[B](codecB: Codec[B])(using Unit =:= A): Codec[B]

Assuming A is Unit, creates a Codec[B] that: encodes the unit followed by a B; decodes a unit followed by a B and discards the decoded unit.

Assuming A is Unit, creates a Codec[B] that: encodes the unit followed by a B; decodes a unit followed by a B and discards the decoded unit.

Operator alias of dropLeft.

Attributes

Inherited from:
Codec
Source:
Codec.scala

Deprecated and Inherited methods

final def hlist: Codec[A *: EmptyTuple]

Attributes

Deprecated
true
Inherited from:
Codec
Source:
Codec.scala
Generated with