Add Item to RngCore

rand_core/src/impls.rs

@@ -239,6 +239,8 @@ impl<R: BlockRngCore> BlockRng<R> {
 impl<R: BlockRngCore<Item=u32>> RngCore for BlockRng<R>
 where <R as BlockRngCore>::Results: AsRef<[u32]>
 {
+    type Item = R::Results;
+
     #[inline(always)]
     fn next_u32(&mut self) -> u32 {
         if self.index >= self.results.as_ref().len() {
@@ -346,6 +348,12 @@ where <R as BlockRngCore>::Results: AsRef<[u32]>
         self.fill_bytes(dest);
         Ok(())
     }
+
+    fn next(&mut self) -> Self::Item {
+        let mut results = R::Results::default();
+        self.core.generate(&mut results);
+        results
+    }
 }
 
 impl<R: BlockRngCore + SeedableRng> SeedableRng for BlockRng<R> {
@@ -423,6 +431,8 @@ impl<R: BlockRngCore> BlockRng64<R> {
 impl<R: BlockRngCore<Item=u64>> RngCore for BlockRng64<R>
 where <R as BlockRngCore>::Results: AsRef<[u64]>
 {
+    type Item = R::Results;
+
     #[inline(always)]
     fn next_u32(&mut self) -> u32 {
         let mut index = self.index * 2 - self.half_used as usize;
@@ -525,6 +535,12 @@ where <R as BlockRngCore>::Results: AsRef<[u64]>
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
         Ok(self.fill_bytes(dest))
     }
+
+    fn next(&mut self) -> Self::Item {
+        let mut results = R::Results::default();
+        self.core.generate(&mut results);
+        results
+    }
 }
 
 impl<R: BlockRngCore + SeedableRng> SeedableRng for BlockRng64<R> {

rand_core/src/lib.rs

@@ -140,6 +140,9 @@ pub mod le;
 /// [`next_u64`]: trait.RngCore.html#tymethod.next_u64
 /// [`CryptoRng`]: trait.CryptoRng.html
 pub trait RngCore {
+    // Type of the values natively generated by this RNG.
+    type Item;
+
     /// Return the next random `u32`.
     ///
     /// RNGs must implement at least one method from this trait directly. In
@@ -186,6 +189,9 @@ pub trait RngCore {
     /// 
     /// [`fill_bytes`]: trait.RngCore.html#method.fill_bytes
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error>;
+
+    /// Return a native value
+    fn next(&mut self) -> Self::Item;
 }
 
 /// A trait for RNGs which do not generate random numbers individually, but in
@@ -349,6 +355,8 @@ pub trait SeedableRng: Sized {
 
 
 impl<'a, R: RngCore + ?Sized> RngCore for &'a mut R {
+    type Item = R::Item;
+
     #[inline(always)]
     fn next_u32(&mut self) -> u32 {
         (**self).next_u32()
@@ -366,10 +374,16 @@ impl<'a, R: RngCore + ?Sized> RngCore for &'a mut R {
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
         (**self).try_fill_bytes(dest)
     }
+
+    fn next(&mut self) -> Self::Item {
+        (**self).next()
+    }
 }
 
 #[cfg(feature="alloc")]
 impl<R: RngCore + ?Sized> RngCore for Box<R> {
+    type Item = R::Item;
+
     #[inline(always)]
     fn next_u32(&mut self) -> u32 {
         (**self).next_u32()
@@ -387,4 +401,8 @@ impl<R: RngCore + ?Sized> RngCore for Box<R> {
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
         (**self).try_fill_bytes(dest)
     }
+
+    fn next(&mut self) -> Self::Item {
+        (**self).next()
+    }
 }

src/jitter.rs

@@ -781,6 +781,8 @@ fn black_box<T>(dummy: T) -> T {
 }
 
 impl RngCore for JitterRng {
+    type Item = u64;
+
     fn next_u32(&mut self) -> u32 {
         // We want to use both parts of the generated entropy
         if self.data_half_used {
@@ -810,6 +812,10 @@ impl RngCore for JitterRng {
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
         Ok(self.fill_bytes(dest))
     }
+
+    fn next(&mut self) -> Self::Item {
+       self.gen_entropy()
+    }
 }
 
 impl CryptoRng for JitterRng {}

src/prng/chacha.rs

@@ -68,6 +68,8 @@ const STATE_WORDS: usize = 16;
 pub struct ChaChaRng(BlockRng<ChaChaCore>);
 
 impl RngCore for ChaChaRng {
+    type Item = <ChaChaCore as BlockRngCore>::Results;
+
     #[inline]
     fn next_u32(&mut self) -> u32 {
         self.0.next_u32()
@@ -87,6 +89,10 @@ impl RngCore for ChaChaRng {
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
         self.0.try_fill_bytes(dest)
     }
+
+    fn next(&mut self) -> Self::Item {
+       self.0.next()
+    }
 }
 
 impl SeedableRng for ChaChaRng {

src/prng/hc128.rs

@@ -65,6 +65,8 @@ const SEED_WORDS: usize = 8; // 128 bit key followed by 128 bit iv
 pub struct Hc128Rng(BlockRng<Hc128Core>);
 
 impl RngCore for Hc128Rng {
+    type Item = <Hc128Core as BlockRngCore>::Results;
+
     #[inline(always)]
     fn next_u32(&mut self) -> u32 {
         self.0.next_u32()
@@ -82,6 +84,10 @@ impl RngCore for Hc128Rng {
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
         self.0.try_fill_bytes(dest)
     }
+
+    fn next(&mut self) -> Self::Item {
+       self.0.next()
+    }
 }
 
 impl SeedableRng for Hc128Rng {

src/prng/isaac.rs

@@ -91,6 +91,8 @@ const RAND_SIZE: usize = 1 << RAND_SIZE_LEN;
 pub struct IsaacRng(BlockRng<IsaacCore>);
 
 impl RngCore for IsaacRng {
+    type Item = <IsaacCore as BlockRngCore>::Results;
+
     #[inline(always)]
     fn next_u32(&mut self) -> u32 {
         self.0.next_u32()
@@ -108,6 +110,10 @@ impl RngCore for IsaacRng {
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
         self.0.try_fill_bytes(dest)
     }
+
+    fn next(&mut self) -> Self::Item {
+       self.0.next()
+    }
 }
 
 impl SeedableRng for IsaacRng {

src/prng/isaac64.rs

@@ -81,6 +81,8 @@ const RAND_SIZE: usize = 1 << RAND_SIZE_LEN;
 pub struct Isaac64Rng(BlockRng64<Isaac64Core>);
 
 impl RngCore for Isaac64Rng {
+    type Item = <Isaac64Core as BlockRngCore>::Results;
+
     #[inline(always)]
     fn next_u32(&mut self) -> u32 {
         self.0.next_u32()
@@ -98,6 +100,10 @@ impl RngCore for Isaac64Rng {
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
         self.0.try_fill_bytes(dest)
     }
+
+    fn next(&mut self) -> Self::Item {
+       self.0.next()
+    }
 }
 
 impl SeedableRng for Isaac64Rng {

src/prng/xorshift.rs

@@ -59,6 +59,8 @@ impl XorShiftRng {
 }
 
 impl RngCore for XorShiftRng {
+    type Item = u32;
+
     #[inline]
     fn next_u32(&mut self) -> u32 {
         let x = self.x;
@@ -82,6 +84,10 @@ impl RngCore for XorShiftRng {
     fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
         Ok(self.fill_bytes(dest))
     }
+
+    fn next(&mut self) -> Self::Item {
+       self.next_u32()
+    }
 }
 
 impl SeedableRng for XorShiftRng {