Create SeedableFromSequence protocol

Sources/RandomKit/Types/RandomGenerator/ChaCha.swift

@@ -32,7 +32,13 @@
 /// [1]: http://cr.yp.to/chacha.html
 /// [2]: https://en.wikipedia.org/wiki/Salsa20#ChaCha_variant
 /// [3]: https://doc.rust-lang.org/rand/rand/chacha/struct.ChaChaRng.html
-public struct ChaCha: RandomBytesGenerator, Seedable, SeedableFromRandomGenerator {
+public struct ChaCha: RandomBytesGenerator, Seedable, SeedableFromSequence, SeedableFromRandomGenerator {
+
+    /// The seed type.
+    public typealias Seed = UnsafeBufferPointer<UInt32>
+
+    /// The seed sequence's element type.
+    public typealias SeedSequenceElement = UInt32
 
     private typealias _State = _Array16<UInt32>
 
@@ -79,12 +85,6 @@ public struct ChaCha: RandomBytesGenerator, Seedable, SeedableFromRandomGenerato
         self._index = _index
     }
 
-    /// Creates an instance from `seed`.
-    public init(seed: UnsafeBufferPointer<UInt32>) {
-        self = ._empty
-        reseed(with: seed)
-    }
-
     /// Creates an instance from `seed`.
     public init<S: Sequence>(seed: S) where S.Iterator.Element == UInt32 {
         self = ._empty
@@ -128,10 +128,6 @@ public struct ChaCha: RandomBytesGenerator, Seedable, SeedableFromRandomGenerato
         }
     }
 
-    private mutating func _reseed<S: Sequence>(with seed: S) where S.Iterator.Element == UInt32 {
-        reseed(with: seed)
-    }
-
     /// Sets the internal 128-bit counter.
     public mutating func setCounter(low: UInt64, high: UInt64) {
         _state.12 = UInt32(truncatingBitPattern: low)
@@ -141,12 +137,6 @@ public struct ChaCha: RandomBytesGenerator, Seedable, SeedableFromRandomGenerato
         _index = ChaCha._stateCount
     }
 
-    /// Reseeds `self` with `seed`.
-    public mutating func reseed(with seed: UnsafeBufferPointer<UInt32>) {
-        // Required to specify method with same name.
-        _reseed(with: seed)
-    }
-
     /// Reseeds `self` with `seed`.
     public mutating func reseed<S: Sequence>(with seed: S) where S.Iterator.Element == UInt32 {
         _reset()

Sources/RandomKit/Types/RandomGenerator/Seedable.swift

@@ -40,14 +40,34 @@ public protocol Seedable {
 }
 
 extension Seedable {
-
     /// Reseeds `self` with `seed`.
     public mutating func reseed(with seed: Seed) {
         self = Self(seed: seed)
     }
+}
+
+/// A type that can be seeded by a sequence.
+public protocol SeedableFromSequence {
+
+    /// The seed sequence's element type.
+    associatedtype SeedSequenceElement
+
+    /// Creates an instance from `seed`.
+    init<S: Sequence>(seed: S) where S.Iterator.Element == SeedSequenceElement
+
+    /// Reseeds `self` with `seed`.
+    mutating func reseed<S: Sequence>(with seed: S) where S.Iterator.Element == SeedSequenceElement
 
 }
 
+
+extension SeedableFromSequence {
+    /// Reseeds `self` with `seed`.
+    public mutating func reseed<S: Sequence>(with sequence: S) where S.Iterator.Element == SeedSequenceElement {
+        self = Self(seed: sequence)
+    }
+}
+
 /// A type that can be seeded by another `randomGenerator`.
 public protocol SeedableFromRandomGenerator: Random {
 
@@ -113,3 +133,29 @@ extension Seedable where Self: SeedableFromRandomGenerator, Seed: Random {
     }
 
 }
+
+extension Seedable where Self: SeedableFromSequence, Seed: Sequence, Seed.Iterator.Element == Self.SeedSequenceElement {
+
+    @inline(__always)
+    private init<S: Sequence>(_seed: S) where S.Iterator.Element == SeedSequenceElement {
+        self.init(seed: _seed)
+    }
+
+    /// Creates an instance from `seed`.
+    public init(seed: Seed) {
+        // Required to specify initializer with same argument.
+        self.init(_seed: seed)
+    }
+
+    @inline(__always)
+    private mutating func _reseed<S: Sequence>(with _seed: S) where S.Iterator.Element == SeedSequenceElement {
+        reseed(with: _seed)
+    }
+
+    /// Reseeds `self` with `seed`.
+    public mutating func reseed(with seed: Seed) {
+        // Required to specify method with same name.
+        _reseed(with: seed)
+    }
+
+}