Make BlockRng{64} fields private

Author: pitdicker

rand_core/src/impls.rs

@@ -191,9 +191,9 @@ pub struct BlockRng<R: BlockRngCore + ?Sized> {
     #[cfg_attr(feature="serde-1", serde(bound(
         serialize = "R::Results: Serialize",
         deserialize = "R::Results: Deserialize<'de>")))]
-    pub results: R::Results,
-    pub index: usize,
-    pub core: R,
+    results: R::Results,
+    index: usize,
+    core: R,
 }
 
 // Custom Debug implementation that does not expose the contents of `results`.
@@ -207,6 +207,35 @@ impl<R: BlockRngCore + fmt::Debug> fmt::Debug for BlockRng<R> {
     }
 }
 
+impl<R: BlockRngCore> BlockRng<R> {
+    /// Create a new `BlockRng` from an existing RNG implementing
+    /// `BlockRngCore`. Results will be generated on first use.
+    pub fn new(core: R) -> BlockRng<R>{
+        let results_empty = R::Results::default();
+        BlockRng {
+            core,
+            index: results_empty.as_ref().len(),
+            results: results_empty,
+        }
+    }
+
+    /// Return a reference the wrapped `BlockRngCore`.
+    pub fn inner(&self) -> &R {
+        &self.core
+    }
+
+    /// Return a mutable reference the wrapped `BlockRngCore`.
+    pub fn inner_mut(&mut self) -> &mut R {
+        &mut self.core
+    }
+
+    // Reset the number of available results.
+    // This will force a new set of results to be generated on next use.
+    pub fn reset(&mut self) {
+        self.index = self.results.as_ref().len();
+    }
+}
+
 impl<R: BlockRngCore<Item=u32>> RngCore for BlockRng<R>
 where <R as BlockRngCore>::Results: AsRef<[u32]>
 {
@@ -323,21 +352,11 @@ impl<R: BlockRngCore + SeedableRng> SeedableRng for BlockRng<R> {
     type Seed = R::Seed;
 
     fn from_seed(seed: Self::Seed) -> Self {
-        let results_empty = R::Results::default();
-        Self {
-            core: R::from_seed(seed),
-            index: results_empty.as_ref().len(), // generate on first use
-            results: results_empty,
-        }
+        Self::new(R::from_seed(seed))
     }
 
     fn from_rng<S: RngCore>(rng: S) -> Result<Self, Error> {
-        let results_empty = R::Results::default();
-        Ok(Self {
-            core: R::from_rng(rng)?,
-            index: results_empty.as_ref().len(), // generate on first use
-            results: results_empty,
-        })
+        Ok(Self::new(R::from_rng(rng)?))
     }
 }
 
@@ -358,10 +377,10 @@ pub struct BlockRng64<R: BlockRngCore + ?Sized> {
     #[cfg_attr(feature="serde-1", serde(bound(
         serialize = "R::Results: Serialize",
         deserialize = "R::Results: Deserialize<'de>")))]
-    pub results: R::Results,
-    pub index: usize,
-    pub half_used: bool, // true if only half of the previous result is used
-    pub core: R,
+    results: R::Results,
+    index: usize,
+    half_used: bool, // true if only half of the previous result is used
+    core: R,
 }
 
 // Custom Debug implementation that does not expose the contents of `results`.
@@ -376,6 +395,31 @@ impl<R: BlockRngCore + fmt::Debug> fmt::Debug for BlockRng64<R> {
     }
 }
 
+impl<R: BlockRngCore> BlockRng64<R> {
+    /// Create a new `BlockRng` from an existing RNG implementing
+    /// `BlockRngCore`. Results will be generated on first use.
+    pub fn new(core: R) -> BlockRng64<R>{
+        let results_empty = R::Results::default();
+        BlockRng64 {
+            core,
+            index: results_empty.as_ref().len(),
+            half_used: false,
+            results: results_empty,
+        }
+    }
+
+    /// Return a mutable reference the wrapped `BlockRngCore`.
+    pub fn inner(&mut self) -> &mut R {
+        &mut self.core
+    }
+
+    // Reset the number of available results.
+    // This will force a new set of results to be generated on next use.
+    pub fn reset(&mut self) {
+        self.index = self.results.as_ref().len();
+    }
+}
+
 impl<R: BlockRngCore<Item=u64>> RngCore for BlockRng64<R>
 where <R as BlockRngCore>::Results: AsRef<[u64]>
 {
@@ -424,6 +468,7 @@ where <R as BlockRngCore>::Results: AsRef<[u64]>
     #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     fn fill_bytes(&mut self, dest: &mut [u8]) {
         let mut filled = 0;
+        self.half_used = false;
 
         // Continue filling from the current set of results
         if self.index < self.results.as_ref().len() {
@@ -461,11 +506,11 @@ where <R as BlockRngCore>::Results: AsRef<[u64]>
     #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
     fn fill_bytes(&mut self, dest: &mut [u8]) {
         let mut read_len = 0;
+        self.half_used = false;
         while read_len < dest.len() {
             if self.index as usize >= self.results.as_ref().len() {
                 self.core.generate(&mut self.results);
                 self.index = 0;
-                self.half_used = false;
             }
 
             let (consumed_u64, filled_u8) =
@@ -486,23 +531,11 @@ impl<R: BlockRngCore + SeedableRng> SeedableRng for BlockRng64<R> {
     type Seed = R::Seed;
 
     fn from_seed(seed: Self::Seed) -> Self {
-        let results_empty = R::Results::default();
-        Self {
-            core: R::from_seed(seed),
-            index: results_empty.as_ref().len(), // generate on first use
-            half_used: false,
-            results: results_empty,
-        }
+        Self::new(R::from_seed(seed))
     }
 
     fn from_rng<S: RngCore>(rng: S) -> Result<Self, Error> {
-        let results_empty = R::Results::default();
-        Ok(Self {
-            core: R::from_rng(rng)?,
-            index: results_empty.as_ref().len(), // generate on first use
-            half_used: false,
-            results: results_empty,
-        })
+        Ok(Self::new(R::from_rng(rng)?))
     }
 }
 

src/prng/chacha.rs

@@ -156,8 +156,8 @@ impl ChaChaRng {
     /// assert_eq!(rng1.next_u32(), rng2.next_u32());
     /// ```
     pub fn set_counter(&mut self, counter_low: u64, counter_high: u64) {
-        self.0.core.set_counter(counter_low, counter_high);
-        self.0.index = STATE_WORDS; // force recomputation on next use
+        self.0.inner_mut().set_counter(counter_low, counter_high);
+        self.0.reset(); // force recomputation on next use
     }
 
     /// Sets the number of rounds to run the ChaCha core algorithm per block to
@@ -179,8 +179,8 @@ impl ChaChaRng {
     /// assert_eq!(rng.next_u32(), 0x2fef003e);
     /// ```
     pub fn set_rounds(&mut self, rounds: usize) {
-        self.0.core.set_rounds(rounds);
-        self.0.index = STATE_WORDS; // force recomputation on next use
+        self.0.inner_mut().set_rounds(rounds);
+        self.0.reset(); // force recomputation on next use
     }
 }
 

src/prng/isaac.rs

@@ -128,28 +128,15 @@ impl IsaacRng {
     ///
     /// DEPRECATED. `IsaacRng::new_from_u64(0)` will produce identical results.
     #[deprecated(since="0.5.0", note="use the NewRng or SeedableRng trait")]
-    pub fn new_unseeded() -> IsaacRng {
+    pub fn new_unseeded() -> Self {
         Self::new_from_u64(0)
     }
 
-    /// Create an ISAAC random number generator using an u64 as seed.
+    /// Create an ISAAC random number generator using an `u64` as seed.
     /// If `seed == 0` this will produce the same stream of random numbers as
     /// the reference implementation when used unseeded.
-    pub fn new_from_u64(seed: u64) -> IsaacRng {
-        let mut key = [w(0); RAND_SIZE];
-        key[0] = w(seed as u32);
-        key[1] = w((seed >> 32) as u32);
-        IsaacRng(BlockRng {
-            // Initialize with only one pass.
-            // A second pass does not improve the quality here, because all of
-            // the seed was already available in the first round.
-            // Not doing the second pass has the small advantage that if
-            // `seed == 0` this method produces exactly the same state as the
-            // reference implementation when used unseeded.
-            core: IsaacCore::init(key, 1),
-            results: IsaacArray::default(),
-            index: RAND_SIZE, // generate on first use
-        })
+    pub fn new_from_u64(seed: u64) -> Self {
+        IsaacRng(BlockRng::new(IsaacCore::new_from_u64(seed)))
     }
 }
 
@@ -318,6 +305,22 @@ impl IsaacCore {
 
         Self { mem, a: w(0), b: w(0), c: w(0) }
     }
+
+    /// Create an ISAAC random number generator using an `u64` as seed.
+    /// If `seed == 0` this will produce the same stream of random numbers as
+    /// the reference implementation when used unseeded.
+    fn new_from_u64(seed: u64) -> Self {
+        let mut key = [w(0); RAND_SIZE];
+        key[0] = w(seed as u32);
+        key[1] = w((seed >> 32) as u32);
+        // Initialize with only one pass.
+        // A second pass does not improve the quality here, because all of the
+        // seed was already available in the first round.
+        // Not doing the second pass has the small advantage that if
+        // `seed == 0` this method produces exactly the same state as the
+        // reference implementation when used unseeded.
+        Self::init(key, 1)
+    }
 }
 
 impl SeedableRng for IsaacCore {
@@ -470,20 +473,8 @@ mod test {
         let mut read = BufReader::new(&buf[..]);
         let mut deserialized: IsaacRng = bincode::deserialize_from(&mut read).expect("Could not deserialize");
 
-        assert_eq!(rng.0.index, deserialized.0.index);
-        /* Can't assert directly because of the array size */
-        for (orig,deser) in rng.0.results.iter().zip(deserialized.0.results.iter()) {
-            assert_eq!(orig, deser);
-        }
-        for (orig,deser) in rng.0.core.mem.iter().zip(deserialized.0.core.mem.iter()) {
-            assert_eq!(orig, deser);
-        }
-        assert_eq!(rng.0.core.a, deserialized.0.core.a);
-        assert_eq!(rng.0.core.b, deserialized.0.core.b);
-        assert_eq!(rng.0.core.c, deserialized.0.core.c);
-
-        for _ in 0..16 {
-            assert_eq!(rng.next_u64(), deserialized.next_u64());
+        for _ in 0..300 { // more than the 256 buffered results
+            assert_eq!(rng.next_u32(), deserialized.next_u32());
         }
     }
 }

src/prng/isaac64.rs

@@ -118,28 +118,15 @@ impl Isaac64Rng {
     ///
     /// DEPRECATED. `Isaac64Rng::new_from_u64(0)` will produce identical results.
     #[deprecated(since="0.5.0", note="use the NewRng or SeedableRng trait")]
-    pub fn new_unseeded() -> Isaac64Rng {
+    pub fn new_unseeded() -> Self {
         Self::new_from_u64(0)
     }
 
-    /// Create an ISAAC-64 random number generator using an u64 as seed.
+    /// Create an ISAAC-64 random number generator using an `u64` as seed.
     /// If `seed == 0` this will produce the same stream of random numbers as
     /// the reference implementation when used unseeded.
-    pub fn new_from_u64(seed: u64) -> Isaac64Rng {
-        let mut key = [w(0); RAND_SIZE];
-        key[0] = w(seed);
-        Isaac64Rng(BlockRng64 {
-            // Initialize with only one pass.
-            // A second pass does not improve the quality here, because all of
-            // the seed was already available in the first round.
-            // Not doing the second pass has the small advantage that if
-            // `seed == 0` this method produces exactly the same state as the
-            // reference implementation when used unseeded.
-            core: Isaac64Core::init(key, 1),
-            results: IsaacArray::default(),
-            index: RAND_SIZE, // generate on first use
-            half_used: false,
-        })
+    pub fn new_from_u64(seed: u64) -> Self {
+        Isaac64Rng(BlockRng64::new(Isaac64Core::new_from_u64(seed)))
     }
 }
 
@@ -283,6 +270,21 @@ impl Isaac64Core {
 
         Self { mem, a: w(0), b: w(0), c: w(0) }
     }
+
+    /// Create an ISAAC-64 random number generator using an `u64` as seed.
+    /// If `seed == 0` this will produce the same stream of random numbers as
+    /// the reference implementation when used unseeded.
+    pub fn new_from_u64(seed: u64) -> Self {
+        let mut key = [w(0); RAND_SIZE];
+        key[0] = w(seed);
+        // Initialize with only one pass.
+        // A second pass does not improve the quality here, because all of the
+        // seed was already available in the first round.
+        // Not doing the second pass has the small advantage that if
+        // `seed == 0` this method produces exactly the same state as the
+        // reference implementation when used unseeded.
+        Self::init(key, 1)
+    }
 }
 
 impl SeedableRng for Isaac64Core {
@@ -463,20 +465,7 @@ mod test {
         let mut read = BufReader::new(&buf[..]);
         let mut deserialized: Isaac64Rng = bincode::deserialize_from(&mut read).expect("Could not deserialize");
 
-        assert_eq!(rng.0.index, deserialized.0.index);
-        assert_eq!(rng.0.half_used, deserialized.0.half_used);
-        /* Can't assert directly because of the array size */
-        for (orig,deser) in rng.0.results.iter().zip(deserialized.0.results.iter()) {
-            assert_eq!(orig, deser);
-        }
-        for (orig,deser) in rng.0.core.mem.iter().zip(deserialized.0.core.mem.iter()) {
-            assert_eq!(orig, deser);
-        }
-        assert_eq!(rng.0.core.a, deserialized.0.core.a);
-        assert_eq!(rng.0.core.b, deserialized.0.core.b);
-        assert_eq!(rng.0.core.c, deserialized.0.core.c);
-
-        for _ in 0..16 {
+        for _ in 0..300 { // more than the 256 buffered results
             assert_eq!(rng.next_u64(), deserialized.next_u64());
         }
     }