Import fastrand 1.9.0

Test: TH
Change-Id: I022b2c2b3669f8c2573d8af30bfd6feb2e37cf7e

14 files changed, 1473 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..869f314
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,86 @@
+# Version 1.9.0
+
+- Add `Rng::fill()` (#35, #43)
+- Add `#[must_use]` to `Rng::with_seed()` (#46)
+
+# Version 1.8.0
+
+- Add `get_seed()` and `Rng::get_seed()` (#33)
+
+# Version 1.7.0
+
+- Add `char()` and `Rng::char()` (#25)
+
+# Version 1.6.0
+
+- Implement `PartialEq` and `Eq` for `Rng` (#23)
+
+# Version 1.5.0
+
+- Switch to Wyrand (#14)
+
+# Version 1.4.1
+
+- Fix bug when generating a signed integer within a range (#16)
+
+# Version 1.4.0
+
+- Add wasm support.
+
+# Version 1.3.5
+
+- Reword docs.
+- Add `Rng::with_seed()`.
+
+# Version 1.3.4
+
+- Implement `Clone` for `Rng`.
+
+# Version 1.3.3
+
+- Forbid unsafe code.
+
+# Version 1.3.2
+
+- Support older Rust versions.
+
+# Version 1.3.1
+
+- Tweak Cargo keywords.
+
+# Version 1.3.0
+
+- Add `f32()` and `f64()`.
+- Add `lowercase()`, `uppercase()`, `alphabetic()`, and `digit()`.
+
+# Version 1.2.4
+
+- Switch to PCG XSH RR 64/32.
+- Fix a bug in `gen_mod_u128`.
+- Fix bias in ranges.
+
+# Version 1.2.3
+
+- Support Rust 1.32.0
+
+# Version 1.2.2
+
+- Use `std::$t::MAX` rather than `$t::MAX` to support older Rust versions.
+
+# Version 1.2.1
+
+- Inline all functions.
+
+# Version 1.2.0
+
+- Add `Rng` struct.
+
+# Version 1.1.0
+
+- Switch to PCG implementation.
+- Add `alphanumeric()`.
+- Add `seed()`.
+
+# Version 1.0.0
+
+- Initial version
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..7cc602f
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,53 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2018"
+rust-version = "1.34"
+name = "fastrand"
+version = "1.9.0"
+authors = ["Stjepan Glavina <stjepang@gmail.com>"]
+exclude = ["/.*"]
+description = "A simple and fast random number generator"
+readme = "README.md"
+keywords = [
+    "simple",
+    "fast",
+    "rand",
+    "random",
+    "wyrand",
+]
+categories = ["algorithms"]
+license = "Apache-2.0 OR MIT"
+repository = "https://github.com/smol-rs/fastrand"
+
+[dev-dependencies.getrandom]
+version = "0.2"
+
+[dev-dependencies.rand]
+version = "0.8"
+
+[dev-dependencies.wyhash]
+version = "0.5"
+
+[target."cfg(all(target_arch = \"wasm32\", not(target_os = \"wasi\")))".dependencies.instant]
+version = "0.1"
+
+[target."cfg(all(target_arch = \"wasm32\", not(target_os = \"wasi\")))".dev-dependencies.getrandom]
+version = "0.2"
+features = ["js"]
+
+[target."cfg(all(target_arch = \"wasm32\", not(target_os = \"wasi\")))".dev-dependencies.instant]
+version = "0.1"
+features = ["wasm-bindgen"]
+
+[target."cfg(all(target_arch = \"wasm32\", not(target_os = \"wasi\")))".dev-dependencies.wasm-bindgen-test]
+version = "0.3"
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
new file mode 100644
index 0000000..8c80502
--- /dev/null
+++ b/Cargo.toml.orig
@@ -0,0 +1,28 @@
+[package]
+name = "fastrand"
+# When publishing a new version:
+# - Update CHANGELOG.md
+# - Create "v1.x.y" git tag
+version = "1.9.0"
+authors = ["Stjepan Glavina <stjepang@gmail.com>"]
+edition = "2018"
+rust-version = "1.34"
+description = "A simple and fast random number generator"
+license = "Apache-2.0 OR MIT"
+repository = "https://github.com/smol-rs/fastrand"
+keywords = ["simple", "fast", "rand", "random", "wyrand"]
+categories = ["algorithms"]
+exclude = ["/.*"]
+
+[target.'cfg(all(target_arch = "wasm32", not(target_os = "wasi")))'.dependencies]
+instant = "0.1"
+
+[target.'cfg(all(target_arch = "wasm32", not(target_os = "wasi")))'.dev-dependencies]
+instant = { version = "0.1", features = ["wasm-bindgen"] }
+wasm-bindgen-test = "0.3"
+getrandom = { version = "0.2", features = ["js"] }
+
+[dev-dependencies]
+rand = "0.8"
+wyhash = "0.5"
+getrandom = "0.2"
diff --git a/LICENSE b/LICENSE
new file mode 120000
index 0000000..6b579aa
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1 @@
+LICENSE-APACHE
\ No newline at end of file
diff --git a/LICENSE-APACHE b/LICENSE-APACHE
new file mode 100644
index 0000000..16fe87b
--- /dev/null
+++ b/LICENSE-APACHE
@@ -0,0 +1,201 @@
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new file mode 100644
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--- /dev/null
+++ b/LICENSE-MIT
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+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
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diff --git a/METADATA b/METADATA
new file mode 100644
index 0000000..5ec32de
--- /dev/null
+++ b/METADATA
@@ -0,0 +1,20 @@
+name: "fastrand"
+description: "A simple and fast random number generator"
+third_party {
+  url {
+    type: HOMEPAGE
+    value: "https://crates.io/crates/fastrand"
+  }
+  url {
+    type: ARCHIVE
+    value: "https://static.crates.io/crates/fastrand/fastrand-1.9.0.crate"
+  }
+  version: "1.9.0"
+  # Dual-licensed, using the least restrictive per go/thirdpartylicenses#same.
+  license_type: NOTICE
+  last_upgrade_date {
+    year: 2023
+    month: 2
+    day: 17
+  }
+}
diff --git a/MODULE_LICENSE_APACHE2 b/MODULE_LICENSE_APACHE2
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/MODULE_LICENSE_APACHE2
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..45dc4dd
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1 @@
+include platform/prebuilts/rust:master:/OWNERS
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..0da0612
--- /dev/null
+++ b/README.md
@@ -0,0 +1,92 @@
+# fastrand
+
+[![Build](https://github.com/smol-rs/fastrand/workflows/Build%20and%20test/badge.svg)](
+https://github.com/smol-rs/fastrand/actions)
+[![License](https://img.shields.io/badge/license-Apache--2.0_OR_MIT-blue.svg)](
+https://github.com/smol-rs/fastrand)
+[![Cargo](https://img.shields.io/crates/v/fastrand.svg)](
+https://crates.io/crates/fastrand)
+[![Documentation](https://docs.rs/fastrand/badge.svg)](
+https://docs.rs/fastrand)
+
+A simple and fast random number generator.
+
+The implementation uses [Wyrand](https://github.com/wangyi-fudan/wyhash), a simple and fast
+generator but **not** cryptographically secure.
+
+## Examples
+
+Flip a coin:
+
+```rust
+if fastrand::bool() {
+    println!("heads");
+} else {
+    println!("tails");
+}
+```
+
+Generate a random `i32`:
+
+```rust
+let num = fastrand::i32(..);
+```
+
+Choose a random element in an array:
+
+```rust
+let v = vec![1, 2, 3, 4, 5];
+let i = fastrand::usize(..v.len());
+let elem = v[i];
+```
+
+Shuffle an array:
+
+```rust
+let mut v = vec![1, 2, 3, 4, 5];
+fastrand::shuffle(&mut v);
+```
+
+Generate a random `Vec` or `String`:
+
+```rust
+use std::iter::repeat_with;
+
+let v: Vec<i32> = repeat_with(|| fastrand::i32(..)).take(10).collect();
+let s: String = repeat_with(fastrand::alphanumeric).take(10).collect();
+```
+
+To get reproducible results on every run, initialize the generator with a seed:
+
+```rust
+// Pick an arbitrary number as seed.
+fastrand::seed(7);
+
+// Now this prints the same number on every run:
+println!("{}", fastrand::u32(..));
+```
+
+To be more efficient, create a new `Rng` instance instead of using the thread-local
+generator:
+
+```rust
+use std::iter::repeat_with;
+
+let rng = fastrand::Rng::new();
+let mut bytes: Vec<u8> = repeat_with(|| rng.u8(..)).take(10_000).collect();
+```
+
+## License
+
+Licensed under either of
+
+ * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+ * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
+
+at your option.
+
+#### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
+dual licensed as above, without any additional terms or conditions.
diff --git a/benches/bench.rs b/benches/bench.rs
new file mode 100644
index 0000000..4b882b7
--- /dev/null
+++ b/benches/bench.rs
@@ -0,0 +1,98 @@
+#![feature(test)]
+
+extern crate test;
+
+use rand::prelude::*;
+use test::Bencher;
+use wyhash::WyRng;
+
+#[bench]
+fn shuffle_wyhash(b: &mut Bencher) {
+    let mut rng = WyRng::from_rng(thread_rng()).unwrap();
+    let mut x = (0..100).collect::<Vec<usize>>();
+    b.iter(|| {
+        x.shuffle(&mut rng);
+        x[0]
+    })
+}
+
+#[bench]
+fn shuffle_fastrand(b: &mut Bencher) {
+    let rng = fastrand::Rng::new();
+    let mut x = (0..100).collect::<Vec<usize>>();
+    b.iter(|| {
+        rng.shuffle(&mut x);
+        x[0]
+    })
+}
+
+#[bench]
+fn u8_wyhash(b: &mut Bencher) {
+    let mut rng = WyRng::from_rng(thread_rng()).unwrap();
+    b.iter(|| {
+        let mut sum = 0u8;
+        for _ in 0..10_000 {
+            sum = sum.wrapping_add(rng.gen::<u8>());
+        }
+        sum
+    })
+}
+
+#[bench]
+fn u8_fastrand(b: &mut Bencher) {
+    let rng = fastrand::Rng::new();
+    b.iter(|| {
+        let mut sum = 0u8;
+        for _ in 0..10_000 {
+            sum = sum.wrapping_add(rng.u8(..));
+        }
+        sum
+    })
+}
+
+#[bench]
+fn u32_wyhash(b: &mut Bencher) {
+    let mut rng = WyRng::from_rng(thread_rng()).unwrap();
+    b.iter(|| {
+        let mut sum = 0u32;
+        for _ in 0..10_000 {
+            sum = sum.wrapping_add(rng.gen::<u32>());
+        }
+        sum
+    })
+}
+
+#[bench]
+fn u32_fastrand(b: &mut Bencher) {
+    let rng = fastrand::Rng::new();
+    b.iter(|| {
+        let mut sum = 0u32;
+        for _ in 0..10_000 {
+            sum = sum.wrapping_add(rng.u32(..));
+        }
+        sum
+    })
+}
+
+#[bench]
+fn fill(b: &mut Bencher) {
+    let rng = fastrand::Rng::new();
+    b.iter(|| {
+        // Pick a size that isn't divisble by 8.
+        let mut bytes = [0u8; 367];
+        rng.fill(&mut bytes);
+        bytes
+    })
+}
+
+#[bench]
+fn fill_naive(b: &mut Bencher) {
+    let rng = fastrand::Rng::new();
+    b.iter(|| {
+        let mut bytes = [0u8; 367];
+        for item in &mut bytes {
+            *item = rng.u8(..);
+        }
+        bytes
+    })
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..3f3ec3d
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,706 @@
+//! A simple and fast random number generator.
+//!
+//! The implementation uses [Wyrand](https://github.com/wangyi-fudan/wyhash), a simple and fast
+//! generator but **not** cryptographically secure.
+//!
+//! # Examples
+//!
+//! Flip a coin:
+//!
+//! ```
+//! if fastrand::bool() {
+//!     println!("heads");
+//! } else {
+//!     println!("tails");
+//! }
+//! ```
+//!
+//! Generate a random `i32`:
+//!
+//! ```
+//! let num = fastrand::i32(..);
+//! ```
+//!
+//! Choose a random element in an array:
+//!
+//! ```
+//! let v = vec![1, 2, 3, 4, 5];
+//! let i = fastrand::usize(..v.len());
+//! let elem = v[i];
+//! ```
+//!
+//! Shuffle an array:
+//!
+//! ```
+//! let mut v = vec![1, 2, 3, 4, 5];
+//! fastrand::shuffle(&mut v);
+//! ```
+//!
+//! Generate a random [`Vec`] or [`String`]:
+//!
+//! ```
+//! use std::iter::repeat_with;
+//!
+//! let v: Vec<i32> = repeat_with(|| fastrand::i32(..)).take(10).collect();
+//! let s: String = repeat_with(fastrand::alphanumeric).take(10).collect();
+//! ```
+//!
+//! To get reproducible results on every run, initialize the generator with a seed:
+//!
+//! ```
+//! // Pick an arbitrary number as seed.
+//! fastrand::seed(7);
+//!
+//! // Now this prints the same number on every run:
+//! println!("{}", fastrand::u32(..));
+//! ```
+//!
+//! To be more efficient, create a new [`Rng`] instance instead of using the thread-local
+//! generator:
+//!
+//! ```
+//! use std::iter::repeat_with;
+//!
+//! let rng = fastrand::Rng::new();
+//! let mut bytes: Vec<u8> = repeat_with(|| rng.u8(..)).take(10_000).collect();
+//! ```
+
+#![forbid(unsafe_code)]
+#![warn(missing_docs, missing_debug_implementations, rust_2018_idioms)]
+
+use std::cell::Cell;
+use std::collections::hash_map::DefaultHasher;
+use std::convert::TryInto;
+use std::hash::{Hash, Hasher};
+use std::ops::{Bound, RangeBounds};
+use std::thread;
+
+#[cfg(all(target_arch = "wasm32", not(target_os = "wasi")))]
+use instant::Instant;
+#[cfg(not(all(target_arch = "wasm32", not(target_os = "wasi"))))]
+use std::time::Instant;
+
+/// A random number generator.
+#[derive(Debug, PartialEq, Eq)]
+pub struct Rng(Cell<u64>);
+
+impl Default for Rng {
+    #[inline]
+    fn default() -> Rng {
+        Rng::new()
+    }
+}
+
+impl Clone for Rng {
+    /// Clones the generator by deterministically deriving a new generator based on the initial
+    /// seed.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// // Seed two generators equally, and clone both of them.
+    /// let base1 = fastrand::Rng::new();
+    /// base1.seed(0x4d595df4d0f33173);
+    /// base1.bool(); // Use the generator once.
+    ///
+    /// let base2 = fastrand::Rng::new();
+    /// base2.seed(0x4d595df4d0f33173);
+    /// base2.bool(); // Use the generator once.
+    ///
+    /// let rng1 = base1.clone();
+    /// let rng2 = base2.clone();
+    ///
+    /// assert_eq!(rng1.u64(..), rng2.u64(..), "the cloned generators are identical");
+    /// ```
+    fn clone(&self) -> Rng {
+        Rng::with_seed(self.gen_u64())
+    }
+}
+
+impl Rng {
+    /// Generates a random `u32`.
+    #[inline]
+    fn gen_u32(&self) -> u32 {
+        self.gen_u64() as u32
+    }
+
+    /// Generates a random `u64`.
+    #[inline]
+    fn gen_u64(&self) -> u64 {
+        let s = self.0.get().wrapping_add(0xA0761D6478BD642F);
+        self.0.set(s);
+        let t = u128::from(s) * u128::from(s ^ 0xE7037ED1A0B428DB);
+        (t as u64) ^ (t >> 64) as u64
+    }
+
+    /// Generates a random `u128`.
+    #[inline]
+    fn gen_u128(&self) -> u128 {
+        (u128::from(self.gen_u64()) << 64) | u128::from(self.gen_u64())
+    }
+
+    /// Generates a random `u32` in `0..n`.
+    #[inline]
+    fn gen_mod_u32(&self, n: u32) -> u32 {
+        // Adapted from: https://lemire.me/blog/2016/06/30/fast-random-shuffling/
+        let mut r = self.gen_u32();
+        let mut hi = mul_high_u32(r, n);
+        let mut lo = r.wrapping_mul(n);
+        if lo < n {
+            let t = n.wrapping_neg() % n;
+            while lo < t {
+                r = self.gen_u32();
+                hi = mul_high_u32(r, n);
+                lo = r.wrapping_mul(n);
+            }
+        }
+        hi
+    }
+
+    /// Generates a random `u64` in `0..n`.
+    #[inline]
+    fn gen_mod_u64(&self, n: u64) -> u64 {
+        // Adapted from: https://lemire.me/blog/2016/06/30/fast-random-shuffling/
+        let mut r = self.gen_u64();
+        let mut hi = mul_high_u64(r, n);
+        let mut lo = r.wrapping_mul(n);
+        if lo < n {
+            let t = n.wrapping_neg() % n;
+            while lo < t {
+                r = self.gen_u64();
+                hi = mul_high_u64(r, n);
+                lo = r.wrapping_mul(n);
+            }
+        }
+        hi
+    }
+
+    /// Generates a random `u128` in `0..n`.
+    #[inline]
+    fn gen_mod_u128(&self, n: u128) -> u128 {
+        // Adapted from: https://lemire.me/blog/2016/06/30/fast-random-shuffling/
+        let mut r = self.gen_u128();
+        let mut hi = mul_high_u128(r, n);
+        let mut lo = r.wrapping_mul(n);
+        if lo < n {
+            let t = n.wrapping_neg() % n;
+            while lo < t {
+                r = self.gen_u128();
+                hi = mul_high_u128(r, n);
+                lo = r.wrapping_mul(n);
+            }
+        }
+        hi
+    }
+}
+
+thread_local! {
+    static RNG: Rng = Rng(Cell::new({
+        let mut hasher = DefaultHasher::new();
+        Instant::now().hash(&mut hasher);
+        thread::current().id().hash(&mut hasher);
+        let hash = hasher.finish();
+        (hash << 1) | 1
+    }));
+}
+
+/// Computes `(a * b) >> 32`.
+#[inline]
+fn mul_high_u32(a: u32, b: u32) -> u32 {
+    (((a as u64) * (b as u64)) >> 32) as u32
+}
+
+/// Computes `(a * b) >> 64`.
+#[inline]
+fn mul_high_u64(a: u64, b: u64) -> u64 {
+    (((a as u128) * (b as u128)) >> 64) as u64
+}
+
+/// Computes `(a * b) >> 128`.
+#[inline]
+fn mul_high_u128(a: u128, b: u128) -> u128 {
+    // Adapted from: https://stackoverflow.com/a/28904636
+    let a_lo = a as u64 as u128;
+    let a_hi = (a >> 64) as u64 as u128;
+    let b_lo = b as u64 as u128;
+    let b_hi = (b >> 64) as u64 as u128;
+    let carry = (a_lo * b_lo) >> 64;
+    let carry = ((a_hi * b_lo) as u64 as u128 + (a_lo * b_hi) as u64 as u128 + carry) >> 64;
+    a_hi * b_hi + ((a_hi * b_lo) >> 64) + ((a_lo * b_hi) >> 64) + carry
+}
+
+macro_rules! rng_integer {
+    ($t:tt, $unsigned_t:tt, $gen:tt, $mod:tt, $doc:tt) => {
+        #[doc = $doc]
+        ///
+        /// Panics if the range is empty.
+        #[inline]
+        pub fn $t(&self, range: impl RangeBounds<$t>) -> $t {
+            let panic_empty_range = || {
+                panic!(
+                    "empty range: {:?}..{:?}",
+                    range.start_bound(),
+                    range.end_bound()
+                )
+            };
+
+            let low = match range.start_bound() {
+                Bound::Unbounded => std::$t::MIN,
+                Bound::Included(&x) => x,
+                Bound::Excluded(&x) => x.checked_add(1).unwrap_or_else(panic_empty_range),
+            };
+
+            let high = match range.end_bound() {
+                Bound::Unbounded => std::$t::MAX,
+                Bound::Included(&x) => x,
+                Bound::Excluded(&x) => x.checked_sub(1).unwrap_or_else(panic_empty_range),
+            };
+
+            if low > high {
+                panic_empty_range();
+            }
+
+            if low == std::$t::MIN && high == std::$t::MAX {
+                self.$gen() as $t
+            } else {
+                let len = high.wrapping_sub(low).wrapping_add(1);
+                low.wrapping_add(self.$mod(len as $unsigned_t as _) as $t)
+            }
+        }
+    };
+}
+
+impl Rng {
+    /// Creates a new random number generator.
+    #[inline]
+    pub fn new() -> Rng {
+        Rng::with_seed(
+            RNG.try_with(|rng| rng.u64(..))
+                .unwrap_or(0x4d595df4d0f33173),
+        )
+    }
+
+    /// Creates a new random number generator with the initial seed.
+    #[inline]
+    #[must_use = "this creates a new instance of `Rng`; if you want to initialize the thread-local generator, use `fastrand::seed()` instead"]
+    pub fn with_seed(seed: u64) -> Self {
+        let rng = Rng(Cell::new(0));
+
+        rng.seed(seed);
+        rng
+    }
+
+    /// Generates a random `char` in ranges a-z and A-Z.
+    #[inline]
+    pub fn alphabetic(&self) -> char {
+        const CHARS: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+        let len = CHARS.len() as u8;
+        let i = self.u8(..len);
+        CHARS[i as usize] as char
+    }
+
+    /// Generates a random `char` in ranges a-z, A-Z and 0-9.
+    #[inline]
+    pub fn alphanumeric(&self) -> char {
+        const CHARS: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+        let len = CHARS.len() as u8;
+        let i = self.u8(..len);
+        CHARS[i as usize] as char
+    }
+
+    /// Generates a random `bool`.
+    #[inline]
+    pub fn bool(&self) -> bool {
+        self.u8(..) % 2 == 0
+    }
+
+    /// Generates a random digit in the given `base`.
+    ///
+    /// Digits are represented by `char`s in ranges 0-9 and a-z.
+    ///
+    /// Panics if the base is zero or greater than 36.
+    #[inline]
+    pub fn digit(&self, base: u32) -> char {
+        if base == 0 {
+            panic!("base cannot be zero");
+        }
+        if base > 36 {
+            panic!("base cannot be larger than 36");
+        }
+        let num = self.u8(..base as u8);
+        if num < 10 {
+            (b'0' + num) as char
+        } else {
+            (b'a' + num - 10) as char
+        }
+    }
+
+    /// Generates a random `f32` in range `0..1`.
+    pub fn f32(&self) -> f32 {
+        let b = 32;
+        let f = std::f32::MANTISSA_DIGITS - 1;
+        f32::from_bits((1 << (b - 2)) - (1 << f) + (self.u32(..) >> (b - f))) - 1.0
+    }
+
+    /// Generates a random `f64` in range `0..1`.
+    pub fn f64(&self) -> f64 {
+        let b = 64;
+        let f = std::f64::MANTISSA_DIGITS - 1;
+        f64::from_bits((1 << (b - 2)) - (1 << f) + (self.u64(..) >> (b - f))) - 1.0
+    }
+
+    rng_integer!(
+        i8,
+        u8,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `i8` in the given range."
+    );
+
+    rng_integer!(
+        i16,
+        u16,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `i16` in the given range."
+    );
+
+    rng_integer!(
+        i32,
+        u32,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `i32` in the given range."
+    );
+
+    rng_integer!(
+        i64,
+        u64,
+        gen_u64,
+        gen_mod_u64,
+        "Generates a random `i64` in the given range."
+    );
+
+    rng_integer!(
+        i128,
+        u128,
+        gen_u128,
+        gen_mod_u128,
+        "Generates a random `i128` in the given range."
+    );
+
+    #[cfg(target_pointer_width = "16")]
+    rng_integer!(
+        isize,
+        usize,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `isize` in the given range."
+    );
+    #[cfg(target_pointer_width = "32")]
+    rng_integer!(
+        isize,
+        usize,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `isize` in the given range."
+    );
+    #[cfg(target_pointer_width = "64")]
+    rng_integer!(
+        isize,
+        usize,
+        gen_u64,
+        gen_mod_u64,
+        "Generates a random `isize` in the given range."
+    );
+
+    /// Generates a random `char` in range a-z.
+    #[inline]
+    pub fn lowercase(&self) -> char {
+        const CHARS: &[u8] = b"abcdefghijklmnopqrstuvwxyz";
+        let len = CHARS.len() as u8;
+        let i = self.u8(..len);
+        CHARS[i as usize] as char
+    }
+
+    /// Initializes this generator with the given seed.
+    #[inline]
+    pub fn seed(&self, seed: u64) {
+        self.0.set(seed);
+    }
+
+    /// Gives back **current** seed that is being held by this generator.
+    #[inline]
+    pub fn get_seed(&self) -> u64 {
+        self.0.get()
+    }
+
+    /// Shuffles a slice randomly.
+    #[inline]
+    pub fn shuffle<T>(&self, slice: &mut [T]) {
+        for i in 1..slice.len() {
+            slice.swap(i, self.usize(..=i));
+        }
+    }
+
+    /// Fill a byte slice with random data.
+    #[inline]
+    pub fn fill(&self, slice: &mut [u8]) {
+        // We fill the slice by chunks of 8 bytes, or one block of
+        // WyRand output per new state.
+        let mut chunks = slice.chunks_exact_mut(core::mem::size_of::<u64>());
+        for chunk in chunks.by_ref() {
+            let n = self.gen_u64().to_ne_bytes();
+            // Safe because the chunks are always 8 bytes exactly.
+            chunk.copy_from_slice(&n);
+        }
+
+        let remainder = chunks.into_remainder();
+
+        // Any remainder will always be less than 8 bytes.
+        if !remainder.is_empty() {
+            // Generate one last block of 8 bytes of entropy
+            let n = self.gen_u64().to_ne_bytes();
+
+            // Use the remaining length to copy from block
+            remainder.copy_from_slice(&n[..remainder.len()]);
+        }
+    }
+
+    rng_integer!(
+        u8,
+        u8,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `u8` in the given range."
+    );
+
+    rng_integer!(
+        u16,
+        u16,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `u16` in the given range."
+    );
+
+    rng_integer!(
+        u32,
+        u32,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `u32` in the given range."
+    );
+
+    rng_integer!(
+        u64,
+        u64,
+        gen_u64,
+        gen_mod_u64,
+        "Generates a random `u64` in the given range."
+    );
+
+    rng_integer!(
+        u128,
+        u128,
+        gen_u128,
+        gen_mod_u128,
+        "Generates a random `u128` in the given range."
+    );
+
+    #[cfg(target_pointer_width = "16")]
+    rng_integer!(
+        usize,
+        usize,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `usize` in the given range."
+    );
+    #[cfg(target_pointer_width = "32")]
+    rng_integer!(
+        usize,
+        usize,
+        gen_u32,
+        gen_mod_u32,
+        "Generates a random `usize` in the given range."
+    );
+    #[cfg(target_pointer_width = "64")]
+    rng_integer!(
+        usize,
+        usize,
+        gen_u64,
+        gen_mod_u64,
+        "Generates a random `usize` in the given range."
+    );
+    #[cfg(target_pointer_width = "128")]
+    rng_integer!(
+        usize,
+        usize,
+        gen_u128,
+        gen_mod_u128,
+        "Generates a random `usize` in the given range."
+    );
+
+    /// Generates a random `char` in range A-Z.
+    #[inline]
+    pub fn uppercase(&self) -> char {
+        const CHARS: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+        let len = CHARS.len() as u8;
+        let i = self.u8(..len);
+        CHARS[i as usize] as char
+    }
+
+    /// Generates a random `char` in the given range.
+    ///
+    /// Panics if the range is empty.
+    #[inline]
+    pub fn char(&self, range: impl RangeBounds<char>) -> char {
+        use std::convert::TryFrom;
+
+        let panic_empty_range = || {
+            panic!(
+                "empty range: {:?}..{:?}",
+                range.start_bound(),
+                range.end_bound()
+            )
+        };
+
+        let surrogate_start = 0xd800u32;
+        let surrogate_len = 0x800u32;
+
+        let low = match range.start_bound() {
+            Bound::Unbounded => 0u8 as char,
+            Bound::Included(&x) => x,
+            Bound::Excluded(&x) => {
+                let scalar = if x as u32 == surrogate_start - 1 {
+                    surrogate_start + surrogate_len
+                } else {
+                    x as u32 + 1
+                };
+                char::try_from(scalar).unwrap_or_else(|_| panic_empty_range())
+            }
+        };
+
+        let high = match range.end_bound() {
+            Bound::Unbounded => std::char::MAX,
+            Bound::Included(&x) => x,
+            Bound::Excluded(&x) => {
+                let scalar = if x as u32 == surrogate_start + surrogate_len {
+                    surrogate_start - 1
+                } else {
+                    (x as u32).wrapping_sub(1)
+                };
+                char::try_from(scalar).unwrap_or_else(|_| panic_empty_range())
+            }
+        };
+
+        if low > high {
+            panic_empty_range();
+        }
+
+        let gap = if (low as u32) < surrogate_start && (high as u32) >= surrogate_start {
+            surrogate_len
+        } else {
+            0
+        };
+        let range = high as u32 - low as u32 - gap;
+        let mut val = self.u32(0..=range) + low as u32;
+        if val >= surrogate_start {
+            val += gap;
+        }
+        val.try_into().unwrap()
+    }
+}
+
+/// Initializes the thread-local generator with the given seed.
+#[inline]
+pub fn seed(seed: u64) {
+    RNG.with(|rng| rng.seed(seed))
+}
+
+/// Gives back **current** seed that is being held by the thread-local generator.
+#[inline]
+pub fn get_seed() -> u64 {
+    RNG.with(|rng| rng.get_seed())
+}
+
+/// Generates a random `bool`.
+#[inline]
+pub fn bool() -> bool {
+    RNG.with(|rng| rng.bool())
+}
+
+/// Generates a random `char` in ranges a-z and A-Z.
+#[inline]
+pub fn alphabetic() -> char {
+    RNG.with(|rng| rng.alphabetic())
+}
+
+/// Generates a random `char` in ranges a-z, A-Z and 0-9.
+#[inline]
+pub fn alphanumeric() -> char {
+    RNG.with(|rng| rng.alphanumeric())
+}
+
+/// Generates a random `char` in range a-z.
+#[inline]
+pub fn lowercase() -> char {
+    RNG.with(|rng| rng.lowercase())
+}
+
+/// Generates a random `char` in range A-Z.
+#[inline]
+pub fn uppercase() -> char {
+    RNG.with(|rng| rng.uppercase())
+}
+
+/// Generates a random digit in the given `base`.
+///
+/// Digits are represented by `char`s in ranges 0-9 and a-z.
+///
+/// Panics if the base is zero or greater than 36.
+#[inline]
+pub fn digit(base: u32) -> char {
+    RNG.with(|rng| rng.digit(base))
+}
+
+/// Shuffles a slice randomly.
+#[inline]
+pub fn shuffle<T>(slice: &mut [T]) {
+    RNG.with(|rng| rng.shuffle(slice))
+}
+
+macro_rules! integer {
+    ($t:tt, $doc:tt) => {
+        #[doc = $doc]
+        ///
+        /// Panics if the range is empty.
+        #[inline]
+        pub fn $t(range: impl RangeBounds<$t>) -> $t {
+            RNG.with(|rng| rng.$t(range))
+        }
+    };
+}
+
+integer!(u8, "Generates a random `u8` in the given range.");
+integer!(i8, "Generates a random `i8` in the given range.");
+integer!(u16, "Generates a random `u16` in the given range.");
+integer!(i16, "Generates a random `i16` in the given range.");
+integer!(u32, "Generates a random `u32` in the given range.");
+integer!(i32, "Generates a random `i32` in the given range.");
+integer!(u64, "Generates a random `u64` in the given range.");
+integer!(i64, "Generates a random `i64` in the given range.");
+integer!(u128, "Generates a random `u128` in the given range.");
+integer!(i128, "Generates a random `i128` in the given range.");
+integer!(usize, "Generates a random `usize` in the given range.");
+integer!(isize, "Generates a random `isize` in the given range.");
+integer!(char, "Generates a random `char` in the given range.");
+
+/// Generates a random `f32` in range `0..1`.
+pub fn f32() -> f32 {
+    RNG.with(|rng| rng.f32())
+}
+
+/// Generates a random `f64` in range `0..1`.
+pub fn f64() -> f64 {
+    RNG.with(|rng| rng.f64())
+}
diff --git a/tests/char.rs b/tests/char.rs
new file mode 100644
index 0000000..0f48c57
--- /dev/null
+++ b/tests/char.rs
@@ -0,0 +1,44 @@
+use std::convert::TryFrom;
+use std::ops::RangeBounds;
+
+fn test_char_coverage<R>(n: usize, range: R)
+where
+    R: Iterator<Item = char> + RangeBounds<char> + Clone,
+{
+    use std::collections::HashSet;
+
+    let all: HashSet<char> = range.clone().collect();
+    let mut covered = HashSet::new();
+    for _ in 0..n {
+        let c = fastrand::char(range.clone());
+        assert!(all.contains(&c));
+        covered.insert(c);
+    }
+    assert_eq!(covered, all);
+}
+
+#[test]
+fn test_char() {
+    // ASCII control chars.
+    let nul = 0u8 as char;
+    let soh = 1u8 as char;
+    let stx = 2u8 as char;
+    // Some undefined Hangul Jamo codepoints just before
+    // the surrogate area.
+    let last_jamo = char::try_from(0xd7ffu32).unwrap();
+    let penultimate_jamo = char::try_from(last_jamo as u32 - 1).unwrap();
+    // Private-use codepoints just after the surrogate area.
+    let first_private = char::try_from(0xe000u32).unwrap();
+    let second_private = char::try_from(first_private as u32 + 1).unwrap();
+    // Private-use codepoints at the end of Unicode space.
+    let last_private = std::char::MAX;
+    let penultimate_private = char::try_from(last_private as u32 - 1).unwrap();
+
+    test_char_coverage(100, nul..stx);
+    test_char_coverage(100, nul..=soh);
+
+    test_char_coverage(400, penultimate_jamo..second_private);
+    test_char_coverage(400, penultimate_jamo..=second_private);
+
+    test_char_coverage(100, penultimate_private..=last_private);
+}
diff --git a/tests/smoke.rs b/tests/smoke.rs
new file mode 100644
index 0000000..ff3cea6
--- /dev/null
+++ b/tests/smoke.rs
@@ -0,0 +1,120 @@
+#[cfg(all(target_family = "wasm", not(target_os = "wasi")))]
+use wasm_bindgen_test::wasm_bindgen_test as test;
+
+#[cfg(all(target_family = "wasm", not(target_os = "wasi")))]
+wasm_bindgen_test::wasm_bindgen_test_configure!(run_in_browser);
+
+#[test]
+fn bool() {
+    for x in &[false, true] {
+        while fastrand::bool() != *x {}
+    }
+}
+
+#[test]
+fn u8() {
+    for x in 0..10 {
+        while fastrand::u8(..10) != x {}
+    }
+
+    for x in 200..=u8::MAX {
+        while fastrand::u8(200..) != x {}
+    }
+}
+
+#[test]
+fn i8() {
+    for x in -128..-120 {
+        while fastrand::i8(..-120) != x {}
+    }
+
+    for x in 120..=127 {
+        while fastrand::i8(120..) != x {}
+    }
+}
+
+#[test]
+fn u32() {
+    for n in 1u32..10_000 {
+        let n = n.wrapping_mul(n);
+        let n = n.wrapping_mul(n);
+        if n != 0 {
+            for _ in 0..1000 {
+                assert!(fastrand::u32(..n) < n);
+            }
+        }
+    }
+}
+
+#[test]
+fn u64() {
+    for n in 1u64..10_000 {
+        let n = n.wrapping_mul(n);
+        let n = n.wrapping_mul(n);
+        let n = n.wrapping_mul(n);
+        if n != 0 {
+            for _ in 0..1000 {
+                assert!(fastrand::u64(..n) < n);
+            }
+        }
+    }
+}
+
+#[test]
+fn u128() {
+    for n in 1u128..10_000 {
+        let n = n.wrapping_mul(n);
+        let n = n.wrapping_mul(n);
+        let n = n.wrapping_mul(n);
+        let n = n.wrapping_mul(n);
+        if n != 0 {
+            for _ in 0..1000 {
+                assert!(fastrand::u128(..n) < n);
+            }
+        }
+    }
+}
+
+#[test]
+fn fill() {
+    let r = fastrand::Rng::new();
+    let mut a = [0u8; 64];
+    let mut b = [0u8; 64];
+
+    r.fill(&mut a);
+    r.fill(&mut b);
+
+    assert_ne!(a, b);
+}
+
+#[test]
+fn rng() {
+    let r = fastrand::Rng::new();
+
+    assert_ne!(r.u64(..), r.u64(..));
+
+    r.seed(7);
+    let a = r.u64(..);
+    r.seed(7);
+    let b = r.u64(..);
+    assert_eq!(a, b);
+}
+
+#[test]
+fn rng_init() {
+    let a = fastrand::Rng::new();
+    let b = fastrand::Rng::new();
+    assert_ne!(a.u64(..), b.u64(..));
+
+    a.seed(7);
+    b.seed(7);
+    assert_eq!(a.u64(..), b.u64(..));
+}
+
+#[test]
+fn with_seed() {
+    let a = fastrand::Rng::with_seed(7);
+    let b = fastrand::Rng::new();
+    b.seed(7);
+    assert_eq!(a.u64(..), b.u64(..));
+}