impl PartialEq, Eq for rngs (#979)

Implements #974. As in #975, but defining equality such that the user is not exposed to the fact that one logical state may have different representations in an implementation-specific way.
rust-random · May 29, 2020 · 4b99567 · 4b99567
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -10,6 +10,7 @@ You may also find the [Upgrade Guide](https://rust-random.github.io/book/update.
 
 ## [Unreleased]
 ### Additions
+- impl PartialEq+Eq for StdRng, SmallRng, and StepRng (#975)
 - Added a `serde1` feature and added Serialize/Deserialize to `UniformInt` and `WeightedIndex` (#974)
 
 ## [0.7.3] - 2020-01-10

diff --git a/Cargo.toml b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rand"
-version = "0.7.3"
+version = "0.7.4"
 authors = ["The Rand Project Developers", "The Rust Project Developers"]
 license = "MIT OR Apache-2.0"
 readme = "README.md"
@@ -56,7 +56,7 @@ members = [
 
 [dependencies]
 rand_core = { path = "rand_core", version = "0.5.1" }
-rand_pcg = { path = "rand_pcg", version = "0.2", optional = true }
+rand_pcg = { path = "rand_pcg", version = "0.2.1", optional = true }
 log = { version = "0.4.4", optional = true }
 serde = { version = "1.0.103", features = ["derive"], optional = true }
 
@@ -74,9 +74,9 @@ libc = { version = "0.2.22", optional = true, default-features = false }
 # Emscripten does not support 128-bit integers, which are used by ChaCha code.
 # We work around this by using a different RNG.
 [target.'cfg(not(target_os = "emscripten"))'.dependencies]
-rand_chacha = { path = "rand_chacha", version = "0.2.1", default-features = false, optional = true }
+rand_chacha = { path = "rand_chacha", version = "0.2.3", default-features = false, optional = true }
 [target.'cfg(target_os = "emscripten")'.dependencies]
-rand_hc = { path = "rand_hc", version = "0.2", optional = true }
+rand_hc = { path = "rand_hc", version = "0.2.1", optional = true }
 
 [dev-dependencies]
 rand_pcg = { path = "rand_pcg", version = "0.2" }

diff --git a/rand_chacha/CHANGELOG.md b/rand_chacha/CHANGELOG.md
@@ -5,6 +5,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+- impl PartialEq+Eq for ChaChaXRng and ChaChaXCore (#975)
 - Fix panic on block counter wrap that was occurring in debug builds
 
 ## [0.2.2] - 2020-03-09

diff --git a/rand_chacha/Cargo.toml b/rand_chacha/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rand_chacha"
-version = "0.2.2"
+version = "0.2.3"
 authors = ["The Rand Project Developers", "The Rust Project Developers", "The CryptoCorrosion Contributors"]
 license = "MIT OR Apache-2.0"
 readme = "README.md"
@@ -20,9 +20,9 @@ appveyor = { repository = "rust-random/rand" }
 
 [dependencies]
 rand_core = { path = "../rand_core", version = "0.5" }
-ppv-lite86 = { version = "0.2.6", default-features = false, features = ["simd"] }
+ppv-lite86 = { version = "0.2.8", default-features = false }
 
 [features]
-default = ["std", "simd"]
+default = ["std"]
 std = ["ppv-lite86/std"]
 simd = [] # deprecated
diff --git a/rand_chacha/src/chacha.rs b/rand_chacha/src/chacha.rs
@@ -70,7 +70,7 @@ impl<T> fmt::Debug for Array64<T> {
 macro_rules! chacha_impl {
     ($ChaChaXCore:ident, $ChaChaXRng:ident, $rounds:expr, $doc:expr) => {
         #[doc=$doc]
-        #[derive(Clone)]
+        #[derive(Clone, PartialEq, Eq)]
         pub struct $ChaChaXCore {
             state: ChaCha,
         }
@@ -255,6 +255,14 @@ macro_rules! chacha_impl {
                 }
             }
         }
+
+        impl PartialEq<$ChaChaXRng> for $ChaChaXRng {
+            fn eq(&self, rhs: &$ChaChaXRng) -> bool {
+                self.rng.core.state.stream64_eq(&rhs.rng.core.state)
+                    && self.get_word_pos() == rhs.get_word_pos()
+            }
+        }
+        impl Eq for $ChaChaXRng {}
     }
 }
 

diff --git a/rand_chacha/src/guts.rs b/rand_chacha/src/guts.rs
@@ -21,7 +21,7 @@ const BUFBLOCKS: u64 = 1 << LOG2_BUFBLOCKS;
 pub(crate) const BUFSZ64: u64 = BLOCK64 * BUFBLOCKS;
 pub(crate) const BUFSZ: usize = BUFSZ64 as usize;
 
-#[derive(Clone)]
+#[derive(Clone, PartialEq, Eq)]
 pub struct ChaCha {
     pub(crate) b: vec128_storage,
     pub(crate) c: vec128_storage,
@@ -91,6 +91,14 @@ impl ChaCha {
     pub fn get_stream_param(&self, param: u32) -> u64 {
         get_stream_param(self, param)
     }
+
+    /// Return whether rhs is equal in all parameters except current 64-bit position.
+    #[inline]
+    pub fn stream64_eq(&self, rhs: &Self) -> bool {
+        let self_d: [u32; 4] = self.d.into();
+        let rhs_d: [u32; 4] = rhs.d.into();
+        self.b == rhs.b && self.c == rhs.c && self_d[3] == rhs_d[3] && self_d[2] == rhs_d[2]
+    }
 }
 
 #[inline(always)]

diff --git a/rand_hc/CHANGELOG.md b/rand_hc/CHANGELOG.md
@@ -4,6 +4,9 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+- impl PartialEq+Eq for Hc128Rng and Hc128Core (#975)
+
 ## [0.2.0] - 2019-06-12
 - Bump minor crate version since rand_core bump is a breaking change
 - Switch to Edition 2018

diff --git a/rand_hc/Cargo.toml b/rand_hc/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rand_hc"
-version = "0.2.0"
+version = "0.2.1"
 authors = ["The Rand Project Developers"]
 license = "MIT OR Apache-2.0"
 readme = "README.md"

diff --git a/rand_hc/src/hc128.rs b/rand_hc/src/hc128.rs
@@ -104,6 +104,13 @@ impl SeedableRng for Hc128Rng {
 
 impl CryptoRng for Hc128Rng {}
 
+impl PartialEq for Hc128Rng {
+    fn eq(&self, rhs: &Self) -> bool {
+        self.0.core == rhs.0.core && self.0.index() == rhs.0.index()
+    }
+}
+impl Eq for Hc128Rng {}
+
 /// The core of `Hc128Rng`, used with `BlockRng`.
 #[derive(Clone)]
 pub struct Hc128Core {
@@ -344,6 +351,14 @@ impl SeedableRng for Hc128Core {
 
 impl CryptoRng for Hc128Core {}
 
+// Custom PartialEq implementation as it can't currently be derived from an array of size 1024
+impl PartialEq for Hc128Core {
+    fn eq(&self, rhs: &Self) -> bool {
+        &self.t[..] == &rhs.t[..] && self.counter1024 == rhs.counter1024
+    }
+}
+impl Eq for Hc128Core {}
+
 #[cfg(test)]
 mod test {
     use super::Hc128Rng;

diff --git a/rand_pcg/CHANGELOG.md b/rand_pcg/CHANGELOG.md
@@ -4,6 +4,9 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+- Derive PartialEq+Eq for Lcg64Xsh32, Lcg128Xsl64, and Mcg128Xsl64 (#975)
+
 ## [0.2.1] - 2019-10-22
 - Bump `bincode` version to 1.1.4 to fix minimal-dependency builds
 - Removed unused `autocfg` build dependency.

diff --git a/rand_pcg/Cargo.toml b/rand_pcg/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rand_pcg"
-version = "0.2.1"
+version = "0.2.2"
 authors = ["The Rand Project Developers"]
 license = "MIT OR Apache-2.0"
 readme = "README.md"

diff --git a/rand_pcg/src/pcg128.rs b/rand_pcg/src/pcg128.rs
@@ -29,7 +29,7 @@ use rand_core::{le, Error, RngCore, SeedableRng};
 /// Despite the name, this implementation uses 32 bytes (256 bit) space
 /// comprising 128 bits of state and 128 bits stream selector. These are both
 /// set by `SeedableRng`, using a 256-bit seed.
-#[derive(Clone)]
+#[derive(Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
 pub struct Lcg128Xsl64 {
     state: u128,
@@ -130,7 +130,7 @@ impl RngCore for Lcg128Xsl64 {
 /// Note that compared to the standard `pcg64` (128-bit LCG with PCG-XSL-RR
 /// output function), this RNG is faster, also has a long cycle, and still has
 /// good performance on statistical tests.
-#[derive(Clone)]
+#[derive(Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
 pub struct Mcg128Xsl64 {
     state: u128,

diff --git a/rand_pcg/src/pcg64.rs b/rand_pcg/src/pcg64.rs
@@ -29,7 +29,7 @@ const MULTIPLIER: u64 = 6364136223846793005;
 /// Despite the name, this implementation uses 16 bytes (128 bit) space
 /// comprising 64 bits of state and 64 bits stream selector. These are both set
 /// by `SeedableRng`, using a 128-bit seed.
-#[derive(Clone)]
+#[derive(Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
 pub struct Lcg64Xsh32 {
     state: u64,

diff --git a/src/rngs/mock.rs b/src/rngs/mock.rs
@@ -27,7 +27,7 @@ use serde::{Serialize, Deserialize};
 /// let sample: [u64; 3] = my_rng.gen();
 /// assert_eq!(sample, [2, 3, 4]);
 /// ```
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
 pub struct StepRng {
     v: u64,

diff --git a/src/rngs/small.rs b/src/rngs/small.rs
@@ -73,7 +73,7 @@ type Rng = rand_pcg::Pcg32;
 /// [`thread_rng`]: crate::thread_rng
 /// [rand_chacha]: https://crates.io/crates/rand_chacha
 /// [rand_pcg]: https://crates.io/crates/rand_pcg
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct SmallRng(Rng);
 
 impl RngCore for SmallRng {

diff --git a/src/rngs/std.rs b/src/rngs/std.rs
@@ -32,7 +32,7 @@ pub(crate) use rand_hc::Hc128Core as Core;
 /// the [rand_chacha] crate directly.
 ///
 /// [rand_chacha]: https://crates.io/crates/rand_chacha
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct StdRng(Rng);
 
 impl RngCore for StdRng {