Add fn BlockRng::clear

Author: dhardy

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `BlockRng::reconstruct` and `BlockRng::remaining_results` methods ([#36])
 - Re-export of `core::convert::Infallible` ([#56])
 - `BlockRng::word_offset` method ([#44])
+- `BlockRng::clear` method ([#69])
 
 ### Changed
 - Edition changed to 2024 and MSRV bumped to 1.85 ([rand#1668])

src/block.rs

@@ -120,7 +120,7 @@ where
     }
 }
 
-impl<W: Word + Default, const N: usize, G: Generator<Output = [W; N]>> BlockRng<G> {
+impl<W: Word, const N: usize, G: Generator<Output = [W; N]>> BlockRng<G> {
     /// Create a new `BlockRng` from an existing RNG implementing
     /// `Generator`. Results will be generated on first use.
     #[inline]
@@ -147,9 +147,7 @@ impl<W: Word + Default, const N: usize, G: Generator<Output = [W; N]>> BlockRng<
             None
         }
     }
-}
 
-impl<W: Word, const N: usize, G: Generator<Output = [W; N]>> BlockRng<G> {
     /// Get the index into the result buffer.
     ///
     /// If this is equal to or larger than the size of the result buffer then
@@ -166,6 +164,16 @@ impl<W: Word, const N: usize, G: Generator<Output = [W; N]>> BlockRng<G> {
         self.results[0] = W::from_usize(index);
     }
 
+    /// Clear the results buffer
+    ///
+    /// This overwrites all bits of the results buffer, and thus may be useful
+    /// in conjunction with [`zeroize`](https://docs.rs/zeroize/).
+    #[inline]
+    pub fn clear(&mut self) {
+        self.results = [W::default(); N];
+        self.results[0] = W::from_usize(N);
+    }
+
     /// Re-generate buffer contents, skipping the first `n` words
     ///
     /// Existing buffer contents are discarded. A new set of results is