Import fixedbitset 0.4.2upstream/0.4.2upstream

11 files changed, 2261 insertions, 0 deletions

diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
new file mode 100644
index 0000000..4bb5b77
--- /dev/null
+++ b/.cargo_vcs_info.json
@@ -0,0 +1,6 @@
+{
+  "git": {
+    "sha1": "da287ee91fb539dc1c12028bf820b7e2c414ed35"
+  },
+  "path_in_vcs": ""
+}
\ No newline at end of file
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
new file mode 100644
index 0000000..82b422d
--- /dev/null
+++ b/.github/workflows/rust.yml
@@ -0,0 +1,33 @@
+name: Continuous integration
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+env:
+  CARGO_TERM_COLOR: always
+  CARGO_INCREMENTAL: 0
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust: [1.39.0, stable, nightly]
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions-rs/toolchain@v1
+      with:
+        profile: minimal
+        toolchain: ${{ matrix.rust }}
+        override: true
+    - name: Tests
+      run: |
+        cargo test -v --no-default-features --tests --lib &&
+        cargo build --verbose --features "$FEATURES" &&
+        cargo test --verbose --features "$FEATURES" &&
+        cargo test --verbose --release --features "$FEATURES"
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..540d72e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+target/
+.idea/
+Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..e4773fa
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,35 @@
+# 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]
+name = "fixedbitset"
+version = "0.4.2"
+authors = ["bluss"]
+description = "FixedBitSet is a simple bitset collection"
+documentation = "https://docs.rs/fixedbitset/"
+readme = "README.md"
+keywords = ["container", "data-structure", "bitvec", "bitset", "no_std"]
+categories = ["data-structures"]
+license = "MIT/Apache-2.0"
+repository = "https://github.com/petgraph/fixedbitset"
+[package.metadata.release]
+no-dev-version = true
+tag-name = "{{version}}"
+[dependencies.serde]
+version = "1.0"
+features = ["derive"]
+optional = true
+[dev-dependencies.serde_json]
+version = "1.0"
+
+[features]
+default = ["std"]
+std = []
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
new file mode 100644
index 0000000..1c2bbce
--- /dev/null
+++ b/Cargo.toml.orig
@@ -0,0 +1,27 @@
+[package]
+name = "fixedbitset"
+version = "0.4.2"
+authors = ["bluss"]
+license = "MIT/Apache-2.0"
+readme = "README.md"
+
+description = "FixedBitSet is a simple bitset collection"
+documentation = "https://docs.rs/fixedbitset/"
+repository = "https://github.com/petgraph/fixedbitset"
+
+keywords = ["container", "data-structure", "bitvec", "bitset", "no_std"]
+categories = ["data-structures"]
+
+[features]
+std = []
+default = ["std"]
+
+[package.metadata.release]
+no-dev-version = true
+tag-name = "{{version}}"
+
+[dependencies]
+serde = { version = "1.0", features = ["derive"], optional = true }
+
+[dev-dependencies]
+serde_json = "1.0"
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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diff --git a/LICENSE-MIT b/LICENSE-MIT
new file mode 100644
index 0000000..327cc61
--- /dev/null
+++ b/LICENSE-MIT
@@ -0,0 +1,25 @@
+Copyright (c) 2015-2017
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
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+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
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+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..65ec173
--- /dev/null
+++ b/README.md
@@ -0,0 +1,86 @@
+fixedbitset
+---
+
+A simple bitset container for Rust
+
+Please read the [API documentation here](https://docs.rs/fixedbitset/)
+
+[![build\_status](https://github.com/petgraph/fixedbitset/workflows/Continuous%20integration/badge.svg?branch=master)](https://github.com/petgraph/fixedbitset/actions)
+[![crates](https://img.shields.io/crates/v/fixedbitset.svg)](https://crates.io/crates/fixedbitset)
+
+# Recent Changes
+
+-   0.4.2
+    - [#79](https://github.com/petgraph/fixedbitset/pull/79): Add `is_clear`,
+    clarify `is_empty` and `len` documentation by \@nicopap.
+-   0.4.1
+    - Documentation and formatting fixes.
+-   0.4.0
+    -   [#61](https://github.com/petgraph/fixedbitset/pull/61): Require
+        Rust 1.39.
+    -   [#60](https://github.com/petgraph/fixedbitset/pull/60): Add
+        `const` `FixedBitSet::new` consructor
+        by \@jakobhellermann.
+    -   [#59](https://github.com/petgraph/fixedbitset/pull/59): Add
+        optional `serde` support by \@keshavsn.
+-   0.3.2
+    -   [#18](https://github.com/petgraph/fixedbitset/pull/18): Optimize
+        `ones` using `trailing_zeroes` by \@vks
+-   0.3.1
+    -   Add bit assign operators for references by \@flaghacker
+    -   Improve assertion error messages by \@lovasoa
+    -   Add documentation examples for `with_capacity_and_blocks`
+-   0.3.0
+    -   Add `with_capacity_and_blocks` by \@luizirber
+    -   Add `difference_with` by \@sunshowers
+    -   Implement `Binary` and `Display` traits by \@Dolphindalt
+    -   Add `toggle_range` by \@wirelyre
+-   0.2.0
+    -   Add assign operators for the bit operations by \@jrraymond
+    -   Add `symmetric_difference`, `union_with`, `intersection_with` by
+        \@jrraymond
+    -   Add `is_subset`, `is_superset`, `is_disjoint` by \@nwn
+    -   Add `.toggle(i)` method by \@ShiroUsagi-san
+    -   Add default feature \"std\" which can be disabled to make the
+        crate not link the std library. By \@jonimake and \@bluss
+    -   Require Rust 1.31.
+-   0.1.9
+    -   Add intersection, union, difference iterators by \@jrraymond
+    -   Add intersection: `&` and union: `|` operator implementations by
+        \@jrraymond
+    -   Add Extend and FromIterator implementations (from sequences of
+        bit indices) by \@jrraymond
+-   0.1.8
+    -   Add missing `#[inline]` on the ones iterator
+    -   Fix docs for `insert_range, set_range`
+-   0.1.7
+    -   Add fast methods `.insert_range`, `.set_range` by \@kennytm
+-   0.1.6
+    -   Add iterator `.ones()` by \@mneumann
+    -   Fix bug with `.count_ones()` where it would erronously have an
+        out-of-bounds panic for even block endpoints
+-   0.1.5
+    -   Add method `.count_ones(range)`.
+-   0.1.4
+    -   Remove an assertion in `.copy_bit(from, to)` so that it is in
+        line with the documentation. The `from` bit does not need to be
+        in bounds.
+    -   Improve `.grow()` to use `Vec::resize` internally.
+-   0.1.3
+    -   Add method `.put()` to enable a bit and return previous value
+-   0.1.2
+    -   Add method `.copy_bit()` (by fuine)
+    -   impl Default
+-   0.1.1
+    -   Update documentation URL
+-   0.1.0
+    -   Add method `.grow()`
+
+# License
+
+Dual-licensed to be compatible with the Rust project.
+
+Licensed under the [Apache License, Version 2.0](https://www.apache.org/licenses/LICENSE-2.0)
+ or the [MIT license](https://opensource.org/licenses/MIT),
+ at your option. This file may not be copied, modified, or distributed except
+according to those terms.
diff --git a/benches/benches.rs b/benches/benches.rs
new file mode 100644
index 0000000..ac999b0
--- /dev/null
+++ b/benches/benches.rs
@@ -0,0 +1,133 @@
+#![feature(test)]
+
+extern crate test;
+extern crate fixedbitset;
+use test::Bencher;
+use fixedbitset::{FixedBitSet};
+use std::mem::size_of;
+
+#[inline]
+fn iter_ones_using_contains<F: FnMut(usize)>(fb: &FixedBitSet, f: &mut F) {
+    for bit in 0 .. fb.len() {
+       if fb.contains(bit) {
+           f(bit);
+       }
+    }
+}
+
+#[inline]
+fn iter_ones_using_slice_directly<F: FnMut(usize)>(fb: &FixedBitSet, f: &mut F) {
+    for (block_idx, &block) in fb.as_slice().iter().enumerate() {
+        let mut bit_pos = block_idx * size_of::<u32>() * 8;
+        let mut block: u32 = block;
+
+        while block != 0 {
+            if (block & 1) == 1 {
+                f(bit_pos);
+            }
+            block = block >> 1;
+            bit_pos += 1;
+        }
+    }
+}
+
+#[bench]
+fn bench_iter_ones_using_contains_all_zeros(b: &mut Bencher) {
+    const N: usize = 1_000_000;
+    let fb = FixedBitSet::with_capacity(N);
+
+    b.iter(|| {
+        let mut count = 0;
+        iter_ones_using_contains(&fb, &mut |_bit| count += 1);
+        count
+    });
+}
+
+#[bench]
+fn bench_iter_ones_using_contains_all_ones(b: &mut Bencher) {
+    const N: usize = 1_000_000;
+    let mut fb = FixedBitSet::with_capacity(N);
+    fb.insert_range(..);
+
+    b.iter(|| {
+        let mut count = 0;
+        iter_ones_using_contains(&fb, &mut |_bit| count += 1);
+        count
+    });
+}
+
+#[bench]
+fn bench_iter_ones_using_slice_directly_all_zero(b: &mut Bencher) {
+    const N: usize = 1_000_000;
+    let fb = FixedBitSet::with_capacity(N);
+
+    b.iter(|| {
+       let mut count = 0;
+       iter_ones_using_slice_directly(&fb, &mut |_bit| count += 1);
+       count
+    });
+}
+
+#[bench]
+fn bench_iter_ones_using_slice_directly_all_ones(b: &mut Bencher) {
+    const N: usize = 1_000_000;
+    let mut fb = FixedBitSet::with_capacity(N);
+    fb.insert_range(..);
+
+    b.iter(|| {
+       let mut count = 0;
+       iter_ones_using_slice_directly(&fb, &mut |_bit| count += 1);
+       count
+    });
+}
+
+#[bench]
+fn bench_iter_ones_all_zeros(b: &mut Bencher) {
+    const N: usize = 1_000_000;
+    let fb = FixedBitSet::with_capacity(N);
+
+    b.iter(|| {
+        let mut count = 0;
+        for _ in fb.ones() {
+            count += 1;
+        }
+        count
+    });
+}
+
+#[bench]
+fn bench_iter_ones_all_ones(b: &mut Bencher) {
+    const N: usize = 1_000_000;
+    let mut fb = FixedBitSet::with_capacity(N);
+    fb.insert_range(..);
+
+    b.iter(|| {
+        let mut count = 0;
+        for _ in fb.ones() {
+            count += 1;
+        }
+        count
+    });
+}
+
+#[bench]
+fn bench_insert_range(b: &mut Bencher) {
+    const N: usize = 1_000_000;
+    let mut fb = FixedBitSet::with_capacity(N);
+
+    b.iter(|| {
+        fb.insert_range(..)
+    });
+}
+
+#[bench]
+fn bench_insert_range_using_loop(b: &mut Bencher) {
+    const N: usize = 1_000_000;
+    let mut fb = FixedBitSet::with_capacity(N);
+
+    b.iter(|| {
+        for i in 0..N {
+            fb.insert(i);
+        }
+    });
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..0af705a
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,1673 @@
+//! `FixedBitSet` is a simple fixed size set of bits.
+//!
+//!
+//! ### Crate features
+//!
+//! - `std` (default feature)  
+//!   Disabling this feature disables using std and instead uses crate alloc.
+//!   Requires Rust 1.36 to disable.
+//!
+//! ### Rust Version
+//!
+//! This version of fixedbitset requires Rust 1.39 or later.
+//!
+#![doc(html_root_url = "https://docs.rs/fixedbitset/0.4.2/")]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[cfg(not(feature = "std"))]
+extern crate alloc;
+#[cfg(not(feature = "std"))]
+use alloc::{vec, vec::Vec};
+
+#[cfg(not(feature = "std"))]
+use core as std;
+
+mod range;
+
+#[cfg(feature = "serde")]
+extern crate serde;
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
+use std::fmt::Write;
+use std::fmt::{Binary, Display, Error, Formatter};
+
+pub use range::IndexRange;
+use std::cmp::{Ord, Ordering};
+use std::iter::{Chain, FromIterator};
+use std::ops::{BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign, Index};
+
+const BITS: usize = 32;
+type Block = u32;
+
+#[inline]
+fn div_rem(x: usize, d: usize) -> (usize, usize) {
+    (x / d, x % d)
+}
+
+/// `FixedBitSet` is a simple fixed size set of bits that each can
+/// be enabled (1 / **true**) or disabled (0 / **false**).
+///
+/// The bit set has a fixed capacity in terms of enabling bits (and the
+/// capacity can grow using the `grow` method).
+///
+/// Derived traits depend on both the zeros and ones, so [0,1] is not equal to
+/// [0,1,0].
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct FixedBitSet {
+    data: Vec<Block>,
+    /// length in bits
+    length: usize,
+}
+
+impl FixedBitSet {
+    /// Create a new empty **FixedBitSet**.
+    pub const fn new() -> Self {
+        FixedBitSet {
+            data: Vec::new(),
+            length: 0,
+        }
+    }
+
+    /// Create a new **FixedBitSet** with a specific number of bits,
+    /// all initially clear.
+    pub fn with_capacity(bits: usize) -> Self {
+        let (mut blocks, rem) = div_rem(bits, BITS);
+        blocks += (rem > 0) as usize;
+        FixedBitSet {
+            data: vec![0; blocks],
+            length: bits,
+        }
+    }
+
+    /// Create a new **FixedBitSet** with a specific number of bits,
+    /// initialized from provided blocks.
+    ///
+    /// If the blocks are not the exact size needed for the capacity
+    /// they will be padded with zeros (if shorter) or truncated to
+    /// the capacity (if longer).
+    ///
+    /// For example:
+    /// ```
+    /// let data = vec![4];
+    /// let bs = fixedbitset::FixedBitSet::with_capacity_and_blocks(4, data);
+    /// assert_eq!(format!("{:b}", bs), "0010");
+    /// ```
+    pub fn with_capacity_and_blocks<I: IntoIterator<Item = Block>>(bits: usize, blocks: I) -> Self {
+        let (mut n_blocks, rem) = div_rem(bits, BITS);
+        n_blocks += (rem > 0) as usize;
+        let mut data: Vec<Block> = blocks.into_iter().collect();
+        // Pad data with zeros if smaller or truncate if larger
+        if data.len() != n_blocks {
+            data.resize(n_blocks, 0);
+        }
+        // Disable bits in blocks beyond capacity
+        let end = data.len() * 32;
+        for (block, mask) in Masks::new(bits..end, end) {
+            unsafe {
+                *data.get_unchecked_mut(block) &= !mask;
+            }
+        }
+        FixedBitSet { data, length: bits }
+    }
+
+    /// Grow capacity to **bits**, all new bits initialized to zero
+    pub fn grow(&mut self, bits: usize) {
+        let (mut blocks, rem) = div_rem(bits, BITS);
+        blocks += (rem > 0) as usize;
+        if bits > self.length {
+            self.length = bits;
+            self.data.resize(blocks, 0);
+        }
+    }
+
+    /// The length of the [`FixedBitSet`] in bits.
+    ///
+    /// Note: `len` includes both set and unset bits.
+    /// ```
+    /// # use fixedbitset::FixedBitSet;
+    /// let bitset = FixedBitSet::with_capacity(10);
+    /// // there are 0 set bits, but 10 unset bits
+    /// assert_eq!(bitset.len(), 10);
+    /// ```
+    /// `len` does not return the count of set bits. For that, use
+    /// [`bitset.count_ones(..)`](FixedBitSet::count_ones) instead.
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.length
+    }
+
+    /// `true` if the [`FixedBitSet`] is empty.
+    ///
+    /// Note that an "empty" `FixedBitSet` is a `FixedBitSet` with
+    /// no bits (meaning: it's length is zero). If you want to check
+    /// if all bits are unset, use [`FixedBitSet::is_clear`].
+    ///
+    /// ```
+    /// # use fixedbitset::FixedBitSet;
+    /// let bitset = FixedBitSet::with_capacity(10);
+    /// assert!(!bitset.is_empty());
+    ///
+    /// let bitset = FixedBitSet::with_capacity(0);
+    /// assert!(bitset.is_empty());
+    /// ```
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    /// `true` if all bits in the [`FixedBitSet`] are unset.
+    ///
+    /// As opposed to [`FixedBitSet::is_empty`], which is `true` only for
+    /// sets without any bits, set or unset.
+    ///
+    /// ```
+    /// # use fixedbitset::FixedBitSet;
+    /// let mut bitset = FixedBitSet::with_capacity(10);
+    /// assert!(bitset.is_clear());
+    ///
+    /// bitset.insert(2);
+    /// assert!(!bitset.is_clear());
+    /// ```
+    ///
+    /// This is equivalent to [`bitset.count_ones(..) == 0`](FixedBitSet::count_ones).
+    #[inline]
+    pub fn is_clear(&self) -> bool {
+        self.data.iter().all(|block| *block == 0)
+    }
+
+    /// Return **true** if the bit is enabled in the **FixedBitSet**,
+    /// **false** otherwise.
+    ///
+    /// Note: bits outside the capacity are always disabled.
+    ///
+    /// Note: Also available with index syntax: `bitset[bit]`.
+    #[inline]
+    pub fn contains(&self, bit: usize) -> bool {
+        let (block, i) = div_rem(bit, BITS);
+        match self.data.get(block) {
+            None => false,
+            Some(b) => (b & (1 << i)) != 0,
+        }
+    }
+
+    /// Clear all bits.
+    #[inline]
+    pub fn clear(&mut self) {
+        for elt in &mut self.data[..] {
+            *elt = 0
+        }
+    }
+
+    /// Enable `bit`.
+    ///
+    /// **Panics** if **bit** is out of bounds.
+    #[inline]
+    pub fn insert(&mut self, bit: usize) {
+        assert!(
+            bit < self.length,
+            "insert at index {} exceeds fixbitset size {}",
+            bit,
+            self.length
+        );
+        let (block, i) = div_rem(bit, BITS);
+        unsafe {
+            *self.data.get_unchecked_mut(block) |= 1 << i;
+        }
+    }
+
+    /// Enable `bit`, and return its previous value.
+    ///
+    /// **Panics** if **bit** is out of bounds.
+    #[inline]
+    pub fn put(&mut self, bit: usize) -> bool {
+        assert!(
+            bit < self.length,
+            "put at index {} exceeds fixbitset size {}",
+            bit,
+            self.length
+        );
+        let (block, i) = div_rem(bit, BITS);
+        unsafe {
+            let word = self.data.get_unchecked_mut(block);
+            let prev = *word & (1 << i) != 0;
+            *word |= 1 << i;
+            prev
+        }
+    }
+    /// Toggle `bit` (inverting its state).
+    ///
+    /// ***Panics*** if **bit** is out of bounds
+    #[inline]
+    pub fn toggle(&mut self, bit: usize) {
+        assert!(
+            bit < self.length,
+            "toggle at index {} exceeds fixbitset size {}",
+            bit,
+            self.length
+        );
+        let (block, i) = div_rem(bit, BITS);
+        unsafe {
+            *self.data.get_unchecked_mut(block) ^= 1 << i;
+        }
+    }
+    /// **Panics** if **bit** is out of bounds.
+    #[inline]
+    pub fn set(&mut self, bit: usize, enabled: bool) {
+        assert!(
+            bit < self.length,
+            "set at index {} exceeds fixbitset size {}",
+            bit,
+            self.length
+        );
+        let (block, i) = div_rem(bit, BITS);
+        unsafe {
+            let elt = self.data.get_unchecked_mut(block);
+            if enabled {
+                *elt |= 1 << i;
+            } else {
+                *elt &= !(1 << i);
+            }
+        }
+    }
+
+    /// Copies boolean value from specified bit to the specified bit.
+    ///
+    /// **Panics** if **to** is out of bounds.
+    #[inline]
+    pub fn copy_bit(&mut self, from: usize, to: usize) {
+        assert!(
+            to < self.length,
+            "copy at index {} exceeds fixbitset size {}",
+            to,
+            self.length
+        );
+        let (to_block, t) = div_rem(to, BITS);
+        let enabled = self.contains(from);
+        unsafe {
+            let to_elt = self.data.get_unchecked_mut(to_block);
+            if enabled {
+                *to_elt |= 1 << t;
+            } else {
+                *to_elt &= !(1 << t);
+            }
+        }
+    }
+
+    /// Count the number of set bits in the given bit range.
+    ///
+    /// Use `..` to count the whole content of the bitset.
+    ///
+    /// **Panics** if the range extends past the end of the bitset.
+    #[inline]
+    pub fn count_ones<T: IndexRange>(&self, range: T) -> usize {
+        Masks::new(range, self.length)
+            .map(|(block, mask)| unsafe {
+                let value = *self.data.get_unchecked(block);
+                (value & mask).count_ones() as usize
+            })
+            .sum()
+    }
+
+    /// Sets every bit in the given range to the given state (`enabled`)
+    ///
+    /// Use `..` to set the whole bitset.
+    ///
+    /// **Panics** if the range extends past the end of the bitset.
+    #[inline]
+    pub fn set_range<T: IndexRange>(&mut self, range: T, enabled: bool) {
+        for (block, mask) in Masks::new(range, self.length) {
+            unsafe {
+                if enabled {
+                    *self.data.get_unchecked_mut(block) |= mask;
+                } else {
+                    *self.data.get_unchecked_mut(block) &= !mask;
+                }
+            }
+        }
+    }
+
+    /// Enables every bit in the given range.
+    ///
+    /// Use `..` to make the whole bitset ones.
+    ///
+    /// **Panics** if the range extends past the end of the bitset.
+    #[inline]
+    pub fn insert_range<T: IndexRange>(&mut self, range: T) {
+        self.set_range(range, true);
+    }
+
+    /// Toggles (inverts) every bit in the given range.
+    ///
+    /// Use `..` to toggle the whole bitset.
+    ///
+    /// **Panics** if the range extends past the end of the bitset.
+    #[inline]
+    pub fn toggle_range<T: IndexRange>(&mut self, range: T) {
+        for (block, mask) in Masks::new(range, self.length) {
+            unsafe {
+                *self.data.get_unchecked_mut(block) ^= mask;
+            }
+        }
+    }
+
+    /// View the bitset as a slice of `u32` blocks
+    #[inline]
+    pub fn as_slice(&self) -> &[u32] {
+        &self.data
+    }
+
+    /// View the bitset as a mutable slice of `u32` blocks. Writing past the bitlength in the last
+    /// will cause `contains` to return potentially incorrect results for bits past the bitlength.
+    #[inline]
+    pub fn as_mut_slice(&mut self) -> &mut [u32] {
+        &mut self.data
+    }
+
+    /// Iterates over all enabled bits.
+    ///
+    /// Iterator element is the index of the `1` bit, type `usize`.
+    #[inline]
+    pub fn ones(&self) -> Ones {
+        match self.as_slice().split_first() {
+            Some((&block, rem)) => Ones {
+                bitset: block,
+                block_idx: 0,
+                remaining_blocks: rem,
+            },
+            None => Ones {
+                bitset: 0,
+                block_idx: 0,
+                remaining_blocks: &[],
+            },
+        }
+    }
+
+    /// Returns a lazy iterator over the intersection of two `FixedBitSet`s
+    pub fn intersection<'a>(&'a self, other: &'a FixedBitSet) -> Intersection<'a> {
+        Intersection {
+            iter: self.ones(),
+            other,
+        }
+    }
+
+    /// Returns a lazy iterator over the union of two `FixedBitSet`s.
+    pub fn union<'a>(&'a self, other: &'a FixedBitSet) -> Union<'a> {
+        Union {
+            iter: self.ones().chain(other.difference(self)),
+        }
+    }
+
+    /// Returns a lazy iterator over the difference of two `FixedBitSet`s. The difference of `a`
+    /// and `b` is the elements of `a` which are not in `b`.
+    pub fn difference<'a>(&'a self, other: &'a FixedBitSet) -> Difference<'a> {
+        Difference {
+            iter: self.ones(),
+            other,
+        }
+    }
+
+    /// Returns a lazy iterator over the symmetric difference of two `FixedBitSet`s.
+    /// The symmetric difference of `a` and `b` is the elements of one, but not both, sets.
+    pub fn symmetric_difference<'a>(&'a self, other: &'a FixedBitSet) -> SymmetricDifference<'a> {
+        SymmetricDifference {
+            iter: self.difference(other).chain(other.difference(self)),
+        }
+    }
+
+    /// In-place union of two `FixedBitSet`s.
+    ///
+    /// On calling this method, `self`'s capacity may be increased to match `other`'s.
+    pub fn union_with(&mut self, other: &FixedBitSet) {
+        if other.len() >= self.len() {
+            self.grow(other.len());
+        }
+        for (x, y) in self.data.iter_mut().zip(other.data.iter()) {
+            *x |= *y;
+        }
+    }
+
+    /// In-place intersection of two `FixedBitSet`s.
+    ///
+    /// On calling this method, `self`'s capacity will remain the same as before.
+    pub fn intersect_with(&mut self, other: &FixedBitSet) {
+        for (x, y) in self.data.iter_mut().zip(other.data.iter()) {
+            *x &= *y;
+        }
+        let mn = std::cmp::min(self.data.len(), other.data.len());
+        for wd in &mut self.data[mn..] {
+            *wd = 0;
+        }
+    }
+
+    /// In-place difference of two `FixedBitSet`s.
+    ///
+    /// On calling this method, `self`'s capacity will remain the same as before.
+    pub fn difference_with(&mut self, other: &FixedBitSet) {
+        for (x, y) in self.data.iter_mut().zip(other.data.iter()) {
+            *x &= !*y;
+        }
+
+        // There's no need to grow self or do any other adjustments.
+        //
+        // * If self is longer than other, the bits at the end of self won't be affected since other
+        //   has them implicitly set to 0.
+        // * If other is longer than self, the bits at the end of other are irrelevant since self
+        //   has them set to 0 anyway.
+    }
+
+    /// In-place symmetric difference of two `FixedBitSet`s.
+    ///
+    /// On calling this method, `self`'s capacity may be increased to match `other`'s.
+    pub fn symmetric_difference_with(&mut self, other: &FixedBitSet) {
+        if other.len() >= self.len() {
+            self.grow(other.len());
+        }
+        for (x, y) in self.data.iter_mut().zip(other.data.iter()) {
+            *x ^= *y;
+        }
+    }
+
+    /// Returns `true` if `self` has no elements in common with `other`. This
+    /// is equivalent to checking for an empty intersection.
+    pub fn is_disjoint(&self, other: &FixedBitSet) -> bool {
+        self.data
+            .iter()
+            .zip(other.data.iter())
+            .all(|(x, y)| x & y == 0)
+    }
+
+    /// Returns `true` if the set is a subset of another, i.e. `other` contains
+    /// at least all the values in `self`.
+    pub fn is_subset(&self, other: &FixedBitSet) -> bool {
+        self.data
+            .iter()
+            .zip(other.data.iter())
+            .all(|(x, y)| x & !y == 0)
+            && self.data.iter().skip(other.data.len()).all(|x| *x == 0)
+    }
+
+    /// Returns `true` if the set is a superset of another, i.e. `self` contains
+    /// at least all the values in `other`.
+    pub fn is_superset(&self, other: &FixedBitSet) -> bool {
+        other.is_subset(self)
+    }
+}
+
+impl Binary for FixedBitSet {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
+        if f.alternate() {
+            f.write_str("0b")?;
+        }
+
+        for i in 0..self.length {
+            if self[i] {
+                f.write_char('1')?;
+            } else {
+                f.write_char('0')?;
+            }
+        }
+
+        Ok(())
+    }
+}
+
+impl Display for FixedBitSet {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
+        Binary::fmt(&self, f)
+    }
+}
+
+/// An iterator producing elements in the difference of two sets.
+///
+/// This struct is created by the [`FixedBitSet::difference`] method.
+pub struct Difference<'a> {
+    iter: Ones<'a>,
+    other: &'a FixedBitSet,
+}
+
+impl<'a> Iterator for Difference<'a> {
+    type Item = usize;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        while let Some(nxt) = self.iter.next() {
+            if !self.other.contains(nxt) {
+                return Some(nxt);
+            }
+        }
+        None
+    }
+}
+
+/// An iterator producing elements in the symmetric difference of two sets.
+///
+/// This struct is created by the [`FixedBitSet::symmetric_difference`] method.
+pub struct SymmetricDifference<'a> {
+    iter: Chain<Difference<'a>, Difference<'a>>,
+}
+
+impl<'a> Iterator for SymmetricDifference<'a> {
+    type Item = usize;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}
+
+/// An iterator producing elements in the intersection of two sets.
+///
+/// This struct is created by the [`FixedBitSet::intersection`] method.
+pub struct Intersection<'a> {
+    iter: Ones<'a>,
+    other: &'a FixedBitSet,
+}
+
+impl<'a> Iterator for Intersection<'a> {
+    type Item = usize; // the bit position of the '1'
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        while let Some(nxt) = self.iter.next() {
+            if self.other.contains(nxt) {
+                return Some(nxt);
+            }
+        }
+        None
+    }
+}
+
+/// An iterator producing elements in the union of two sets.
+///
+/// This struct is created by the [`FixedBitSet::union`] method.
+pub struct Union<'a> {
+    iter: Chain<Ones<'a>, Difference<'a>>,
+}
+
+impl<'a> Iterator for Union<'a> {
+    type Item = usize;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}
+
+struct Masks {
+    first_block: usize,
+    first_mask: Block,
+    last_block: usize,
+    last_mask: Block,
+}
+
+impl Masks {
+    #[inline]
+    fn new<T: IndexRange>(range: T, length: usize) -> Masks {
+        let start = range.start().unwrap_or(0);
+        let end = range.end().unwrap_or(length);
+        assert!(
+            start <= end && end <= length,
+            "invalid range {}..{} for a fixedbitset of size {}",
+            start,
+            end,
+            length
+        );
+
+        let (first_block, first_rem) = div_rem(start, BITS);
+        let (last_block, last_rem) = div_rem(end, BITS);
+
+        Masks {
+            first_block: first_block as usize,
+            first_mask: Block::max_value() << first_rem,
+            last_block: last_block as usize,
+            last_mask: (Block::max_value() >> 1) >> (BITS - last_rem - 1),
+            // this is equivalent to `MAX >> (BITS - x)` with correct semantics when x == 0.
+        }
+    }
+}
+
+impl Iterator for Masks {
+    type Item = (usize, Block);
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.first_block.cmp(&self.last_block) {
+            Ordering::Less => {
+                let res = (self.first_block, self.first_mask);
+                self.first_block += 1;
+                self.first_mask = !0;
+                Some(res)
+            }
+            Ordering::Equal => {
+                let mask = self.first_mask & self.last_mask;
+                let res = if mask == 0 {
+                    None
+                } else {
+                    Some((self.first_block, mask))
+                };
+                self.first_block += 1;
+                res
+            }
+            Ordering::Greater => None,
+        }
+    }
+}
+
+/// An  iterator producing the indices of the set bit in a set.
+///
+/// This struct is created by the [`FixedBitSet::ones`] method.
+pub struct Ones<'a> {
+    bitset: Block,
+    block_idx: usize,
+    remaining_blocks: &'a [Block],
+}
+
+impl<'a> Iterator for Ones<'a> {
+    type Item = usize; // the bit position of the '1'
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        while self.bitset == 0 {
+            if self.remaining_blocks.is_empty() {
+                return None;
+            }
+            self.bitset = self.remaining_blocks[0];
+            self.remaining_blocks = &self.remaining_blocks[1..];
+            self.block_idx += 1;
+        }
+        let t = self.bitset & (0 as Block).wrapping_sub(self.bitset);
+        let r = self.bitset.trailing_zeros() as usize;
+        self.bitset ^= t;
+        Some(self.block_idx * BITS + r)
+    }
+}
+
+impl Clone for FixedBitSet {
+    #[inline]
+    fn clone(&self) -> Self {
+        FixedBitSet {
+            data: self.data.clone(),
+            length: self.length,
+        }
+    }
+}
+
+/// Return **true** if the bit is enabled in the bitset,
+/// or **false** otherwise.
+///
+/// Note: bits outside the capacity are always disabled, and thus
+/// indexing a FixedBitSet will not panic.
+impl Index<usize> for FixedBitSet {
+    type Output = bool;
+
+    #[inline]
+    fn index(&self, bit: usize) -> &bool {
+        if self.contains(bit) {
+            &true
+        } else {
+            &false
+        }
+    }
+}
+
+/// Sets the bit at index **i** to **true** for each item **i** in the input **src**.
+impl Extend<usize> for FixedBitSet {
+    fn extend<I: IntoIterator<Item = usize>>(&mut self, src: I) {
+        let iter = src.into_iter();
+        for i in iter {
+            if i >= self.len() {
+                self.grow(i + 1);
+            }
+            self.put(i);
+        }
+    }
+}
+
+/// Return a FixedBitSet containing bits set to **true** for every bit index in
+/// the iterator, other bits are set to **false**.
+impl FromIterator<usize> for FixedBitSet {
+    fn from_iter<I: IntoIterator<Item = usize>>(src: I) -> Self {
+        let mut fbs = FixedBitSet::with_capacity(0);
+        fbs.extend(src);
+        fbs
+    }
+}
+
+impl<'a> BitAnd for &'a FixedBitSet {
+    type Output = FixedBitSet;
+    fn bitand(self, other: &FixedBitSet) -> FixedBitSet {
+        let (short, long) = {
+            if self.len() <= other.len() {
+                (&self.data, &other.data)
+            } else {
+                (&other.data, &self.data)
+            }
+        };
+        let mut data = short.clone();
+        for (data, block) in data.iter_mut().zip(long.iter()) {
+            *data &= *block;
+        }
+        let len = std::cmp::min(self.len(), other.len());
+        FixedBitSet { data, length: len }
+    }
+}
+
+impl<'a> BitAndAssign for FixedBitSet {
+    fn bitand_assign(&mut self, other: Self) {
+        self.intersect_with(&other);
+    }
+}
+
+impl<'a> BitAndAssign<&Self> for FixedBitSet {
+    fn bitand_assign(&mut self, other: &Self) {
+        self.intersect_with(other);
+    }
+}
+
+impl<'a> BitOr for &'a FixedBitSet {
+    type Output = FixedBitSet;
+    fn bitor(self, other: &FixedBitSet) -> FixedBitSet {
+        let (short, long) = {
+            if self.len() <= other.len() {
+                (&self.data, &other.data)
+            } else {
+                (&other.data, &self.data)
+            }
+        };
+        let mut data = long.clone();
+        for (data, block) in data.iter_mut().zip(short.iter()) {
+            *data |= *block;
+        }
+        let len = std::cmp::max(self.len(), other.len());
+        FixedBitSet { data, length: len }
+    }
+}
+
+impl<'a> BitOrAssign for FixedBitSet {
+    fn bitor_assign(&mut self, other: Self) {
+        self.union_with(&other);
+    }
+}
+
+impl<'a> BitOrAssign<&Self> for FixedBitSet {
+    fn bitor_assign(&mut self, other: &Self) {
+        self.union_with(other);
+    }
+}
+
+impl<'a> BitXor for &'a FixedBitSet {
+    type Output = FixedBitSet;
+    fn bitxor(self, other: &FixedBitSet) -> FixedBitSet {
+        let (short, long) = {
+            if self.len() <= other.len() {
+                (&self.data, &other.data)
+            } else {
+                (&other.data, &self.data)
+            }
+        };
+        let mut data = long.clone();
+        for (data, block) in data.iter_mut().zip(short.iter()) {
+            *data ^= *block;
+        }
+        let len = std::cmp::max(self.len(), other.len());
+        FixedBitSet { data, length: len }
+    }
+}
+
+impl<'a> BitXorAssign for FixedBitSet {
+    fn bitxor_assign(&mut self, other: Self) {
+        self.symmetric_difference_with(&other);
+    }
+}
+
+impl<'a> BitXorAssign<&Self> for FixedBitSet {
+    fn bitxor_assign(&mut self, other: &Self) {
+        self.symmetric_difference_with(other);
+    }
+}
+
+#[test]
+fn it_works() {
+    const N: usize = 50;
+    let mut fb = FixedBitSet::with_capacity(N);
+
+    for i in 0..(N + 10) {
+        assert_eq!(fb.contains(i), false);
+    }
+
+    fb.insert(10);
+    fb.set(11, false);
+    fb.set(12, false);
+    fb.set(12, true);
+    fb.set(N - 1, true);
+
+    assert!(fb.contains(10));
+    assert!(!fb.contains(11));
+    assert!(fb.contains(12));
+    assert!(fb.contains(N - 1));
+    for i in 0..N {
+        let contain = i == 10 || i == 12 || i == N - 1;
+        assert_eq!(contain, fb[i]);
+    }
+
+    fb.clear();
+}
+
+#[test]
+fn with_blocks() {
+    let fb = FixedBitSet::with_capacity_and_blocks(50, vec![8u32, 0u32]);
+    assert!(fb.contains(3));
+
+    let ones: Vec<_> = fb.ones().collect();
+    assert_eq!(ones.len(), 1);
+}
+
+#[test]
+fn with_blocks_too_small() {
+    let mut fb = FixedBitSet::with_capacity_and_blocks(500, vec![8u32, 0u32]);
+    fb.insert(400);
+    assert!(fb.contains(400));
+}
+
+#[test]
+fn with_blocks_too_big() {
+    let fb = FixedBitSet::with_capacity_and_blocks(1, vec![8u32]);
+
+    // since capacity is 1, 3 shouldn't be set here
+    assert!(!fb.contains(3));
+}
+
+#[test]
+fn with_blocks_too_big_range_check() {
+    let fb = FixedBitSet::with_capacity_and_blocks(1, vec![0xff]);
+
+    // since capacity is 1, only 0 should be set
+    assert!(fb.contains(0));
+    for i in 1..0xff {
+        assert!(!fb.contains(i));
+    }
+}
+
+#[test]
+fn grow() {
+    let mut fb = FixedBitSet::with_capacity(48);
+    for i in 0..fb.len() {
+        fb.set(i, true);
+    }
+
+    let old_len = fb.len();
+    fb.grow(72);
+    for j in 0..fb.len() {
+        assert_eq!(fb.contains(j), j < old_len);
+    }
+    fb.set(64, true);
+    assert!(fb.contains(64));
+}
+
+#[test]
+fn test_toggle() {
+    let mut fb = FixedBitSet::with_capacity(16);
+    fb.toggle(1);
+    fb.put(2);
+    fb.toggle(2);
+    fb.put(3);
+    assert!(fb.contains(1));
+    assert!(!fb.contains(2));
+    assert!(fb.contains(3));
+}
+
+#[test]
+fn copy_bit() {
+    let mut fb = FixedBitSet::with_capacity(48);
+    for i in 0..fb.len() {
+        fb.set(i, true);
+    }
+    fb.set(42, false);
+    fb.copy_bit(42, 2);
+    assert!(!fb.contains(42));
+    assert!(!fb.contains(2));
+    assert!(fb.contains(1));
+    fb.copy_bit(1, 42);
+    assert!(fb.contains(42));
+    fb.copy_bit(1024, 42);
+    assert!(!fb[42]);
+}
+
+#[test]
+fn count_ones() {
+    let mut fb = FixedBitSet::with_capacity(100);
+    fb.set(11, true);
+    fb.set(12, true);
+    fb.set(7, true);
+    fb.set(35, true);
+    fb.set(40, true);
+    fb.set(77, true);
+    fb.set(95, true);
+    fb.set(50, true);
+    fb.set(99, true);
+    assert_eq!(fb.count_ones(..7), 0);
+    assert_eq!(fb.count_ones(..8), 1);
+    assert_eq!(fb.count_ones(..11), 1);
+    assert_eq!(fb.count_ones(..12), 2);
+    assert_eq!(fb.count_ones(..13), 3);
+    assert_eq!(fb.count_ones(..35), 3);
+    assert_eq!(fb.count_ones(..36), 4);
+    assert_eq!(fb.count_ones(..40), 4);
+    assert_eq!(fb.count_ones(..41), 5);
+    assert_eq!(fb.count_ones(50..), 4);
+    assert_eq!(fb.count_ones(70..95), 1);
+    assert_eq!(fb.count_ones(70..96), 2);
+    assert_eq!(fb.count_ones(70..99), 2);
+    assert_eq!(fb.count_ones(..), 9);
+    assert_eq!(fb.count_ones(0..100), 9);
+    assert_eq!(fb.count_ones(0..0), 0);
+    assert_eq!(fb.count_ones(100..100), 0);
+    assert_eq!(fb.count_ones(7..), 9);
+    assert_eq!(fb.count_ones(8..), 8);
+}
+
+#[test]
+fn ones() {
+    let mut fb = FixedBitSet::with_capacity(100);
+    fb.set(11, true);
+    fb.set(12, true);
+    fb.set(7, true);
+    fb.set(35, true);
+    fb.set(40, true);
+    fb.set(77, true);
+    fb.set(95, true);
+    fb.set(50, true);
+    fb.set(99, true);
+
+    let ones: Vec<_> = fb.ones().collect();
+
+    assert_eq!(vec![7, 11, 12, 35, 40, 50, 77, 95, 99], ones);
+}
+
+#[test]
+fn iter_ones_range() {
+    fn test_range(from: usize, to: usize, capa: usize) {
+        assert!(to <= capa);
+        let mut fb = FixedBitSet::with_capacity(capa);
+        for i in from..to {
+            fb.insert(i);
+        }
+        let ones: Vec<_> = fb.ones().collect();
+        let expected: Vec<_> = (from..to).collect();
+        assert_eq!(expected, ones);
+    }
+
+    for i in 0..100 {
+        test_range(i, 100, 100);
+        test_range(0, i, 100);
+    }
+}
+
+#[should_panic]
+#[test]
+fn count_ones_oob() {
+    let fb = FixedBitSet::with_capacity(100);
+    fb.count_ones(90..101);
+}
+
+#[should_panic]
+#[test]
+fn count_ones_negative_range() {
+    let fb = FixedBitSet::with_capacity(100);
+    fb.count_ones(90..80);
+}
+
+#[test]
+fn count_ones_panic() {
+    for i in 1..128 {
+        let fb = FixedBitSet::with_capacity(i);
+        for j in 0..fb.len() + 1 {
+            for k in j..fb.len() + 1 {
+                assert_eq!(fb.count_ones(j..k), 0);
+            }
+        }
+    }
+}
+
+#[test]
+fn default() {
+    let fb = FixedBitSet::default();
+    assert_eq!(fb.len(), 0);
+}
+
+#[test]
+fn insert_range() {
+    let mut fb = FixedBitSet::with_capacity(97);
+    fb.insert_range(..3);
+    fb.insert_range(9..32);
+    fb.insert_range(37..81);
+    fb.insert_range(90..);
+    for i in 0..97 {
+        assert_eq!(
+            fb.contains(i),
+            i < 3 || 9 <= i && i < 32 || 37 <= i && i < 81 || 90 <= i
+        );
+    }
+    assert!(!fb.contains(97));
+    assert!(!fb.contains(127));
+    assert!(!fb.contains(128));
+}
+
+#[test]
+fn set_range() {
+    let mut fb = FixedBitSet::with_capacity(48);
+    fb.insert_range(..);
+
+    fb.set_range(..32, false);
+    fb.set_range(37.., false);
+    fb.set_range(5..9, true);
+    fb.set_range(40..40, true);
+
+    for i in 0..48 {
+        assert_eq!(fb.contains(i), 5 <= i && i < 9 || 32 <= i && i < 37);
+    }
+    assert!(!fb.contains(48));
+    assert!(!fb.contains(64));
+}
+
+#[test]
+fn toggle_range() {
+    let mut fb = FixedBitSet::with_capacity(40);
+    fb.insert_range(..10);
+    fb.insert_range(34..38);
+
+    fb.toggle_range(5..12);
+    fb.toggle_range(30..);
+
+    for i in 0..40 {
+        assert_eq!(
+            fb.contains(i),
+            i < 5 || 10 <= i && i < 12 || 30 <= i && i < 34 || 38 <= i
+        );
+    }
+    assert!(!fb.contains(40));
+    assert!(!fb.contains(64));
+}
+
+#[test]
+fn bitand_equal_lengths() {
+    let len = 109;
+    let a_end = 59;
+    let b_start = 23;
+    let mut a = FixedBitSet::with_capacity(len);
+    let mut b = FixedBitSet::with_capacity(len);
+    a.set_range(..a_end, true);
+    b.set_range(b_start.., true);
+    let ab = &a & &b;
+    for i in 0..b_start {
+        assert!(!ab.contains(i));
+    }
+    for i in b_start..a_end {
+        assert!(ab.contains(i));
+    }
+    for i in a_end..len {
+        assert!(!ab.contains(i));
+    }
+    assert_eq!(a.len(), ab.len());
+}
+
+#[test]
+fn bitand_first_smaller() {
+    let a_len = 113;
+    let b_len = 137;
+    let len = std::cmp::min(a_len, b_len);
+    let a_end = 97;
+    let b_start = 89;
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.set_range(..a_end, true);
+    b.set_range(b_start.., true);
+    let ab = &a & &b;
+    for i in 0..b_start {
+        assert!(!ab.contains(i));
+    }
+    for i in b_start..a_end {
+        assert!(ab.contains(i));
+    }
+    for i in a_end..len {
+        assert!(!ab.contains(i));
+    }
+    assert_eq!(a.len(), ab.len());
+}
+
+#[test]
+fn bitand_first_larger() {
+    let a_len = 173;
+    let b_len = 137;
+    let len = std::cmp::min(a_len, b_len);
+    let a_end = 107;
+    let b_start = 43;
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.set_range(..a_end, true);
+    b.set_range(b_start.., true);
+    let ab = &a & &b;
+    for i in 0..b_start {
+        assert!(!ab.contains(i));
+    }
+    for i in b_start..a_end {
+        assert!(ab.contains(i));
+    }
+    for i in a_end..len {
+        assert!(!ab.contains(i));
+    }
+    assert_eq!(b.len(), ab.len());
+}
+
+#[test]
+fn intersection() {
+    let len = 109;
+    let a_end = 59;
+    let b_start = 23;
+    let mut a = FixedBitSet::with_capacity(len);
+    let mut b = FixedBitSet::with_capacity(len);
+    a.set_range(..a_end, true);
+    b.set_range(b_start.., true);
+
+    let mut ab = a.intersection(&b).collect::<FixedBitSet>();
+
+    for i in 0..b_start {
+        assert!(!ab.contains(i));
+    }
+    for i in b_start..a_end {
+        assert!(ab.contains(i));
+    }
+    for i in a_end..len {
+        assert!(!ab.contains(i));
+    }
+
+    a.intersect_with(&b);
+    // intersection + collect produces the same results but with a shorter length.
+    ab.grow(a.len());
+    assert_eq!(
+        ab, a,
+        "intersection and intersect_with produce the same results"
+    );
+}
+
+#[test]
+fn union() {
+    let a_len = 173;
+    let b_len = 137;
+    let a_start = 139;
+    let b_end = 107;
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.set_range(a_start.., true);
+    b.set_range(..b_end, true);
+    let ab = a.union(&b).collect::<FixedBitSet>();
+    for i in a_start..a_len {
+        assert!(ab.contains(i));
+    }
+    for i in 0..b_end {
+        assert!(ab.contains(i));
+    }
+    for i in b_end..a_start {
+        assert!(!ab.contains(i));
+    }
+
+    a.union_with(&b);
+    assert_eq!(ab, a, "union and union_with produce the same results");
+}
+
+#[test]
+fn difference() {
+    let a_len = 83;
+    let b_len = 151;
+    let a_start = 0;
+    let a_end = 79;
+    let b_start = 53;
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.set_range(a_start..a_end, true);
+    b.set_range(b_start..b_len, true);
+    let mut a_diff_b = a.difference(&b).collect::<FixedBitSet>();
+    for i in a_start..b_start {
+        assert!(a_diff_b.contains(i));
+    }
+    for i in b_start..b_len {
+        assert!(!a_diff_b.contains(i));
+    }
+
+    a.difference_with(&b);
+    // difference + collect produces the same results but with a shorter length.
+    a_diff_b.grow(a.len());
+    assert_eq!(
+        a_diff_b, a,
+        "difference and difference_with produce the same results"
+    );
+}
+
+#[test]
+fn symmetric_difference() {
+    let a_len = 83;
+    let b_len = 151;
+    let a_start = 47;
+    let a_end = 79;
+    let b_start = 53;
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.set_range(a_start..a_end, true);
+    b.set_range(b_start..b_len, true);
+    let a_sym_diff_b = a.symmetric_difference(&b).collect::<FixedBitSet>();
+    for i in 0..a_start {
+        assert!(!a_sym_diff_b.contains(i));
+    }
+    for i in a_start..b_start {
+        assert!(a_sym_diff_b.contains(i));
+    }
+    for i in b_start..a_end {
+        assert!(!a_sym_diff_b.contains(i));
+    }
+    for i in a_end..b_len {
+        assert!(a_sym_diff_b.contains(i));
+    }
+
+    a.symmetric_difference_with(&b);
+    assert_eq!(
+        a_sym_diff_b, a,
+        "symmetric_difference and _with produce the same results"
+    );
+}
+
+#[test]
+fn bitor_equal_lengths() {
+    let len = 109;
+    let a_start = 17;
+    let a_end = 23;
+    let b_start = 19;
+    let b_end = 59;
+    let mut a = FixedBitSet::with_capacity(len);
+    let mut b = FixedBitSet::with_capacity(len);
+    a.set_range(a_start..a_end, true);
+    b.set_range(b_start..b_end, true);
+    let ab = &a | &b;
+    for i in 0..a_start {
+        assert!(!ab.contains(i));
+    }
+    for i in a_start..b_end {
+        assert!(ab.contains(i));
+    }
+    for i in b_end..len {
+        assert!(!ab.contains(i));
+    }
+    assert_eq!(ab.len(), len);
+}
+
+#[test]
+fn bitor_first_smaller() {
+    let a_len = 113;
+    let b_len = 137;
+    let a_end = 89;
+    let b_start = 97;
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.set_range(..a_end, true);
+    b.set_range(b_start.., true);
+    let ab = &a | &b;
+    for i in 0..a_end {
+        assert!(ab.contains(i));
+    }
+    for i in a_end..b_start {
+        assert!(!ab.contains(i));
+    }
+    for i in b_start..b_len {
+        assert!(ab.contains(i));
+    }
+    assert_eq!(b_len, ab.len());
+}
+
+#[test]
+fn bitor_first_larger() {
+    let a_len = 173;
+    let b_len = 137;
+    let a_start = 139;
+    let b_end = 107;
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.set_range(a_start.., true);
+    b.set_range(..b_end, true);
+    let ab = &a | &b;
+    for i in a_start..a_len {
+        assert!(ab.contains(i));
+    }
+    for i in 0..b_end {
+        assert!(ab.contains(i));
+    }
+    for i in b_end..a_start {
+        assert!(!ab.contains(i));
+    }
+    assert_eq!(a_len, ab.len());
+}
+
+#[test]
+fn bitxor_equal_lengths() {
+    let len = 109;
+    let a_end = 59;
+    let b_start = 23;
+    let mut a = FixedBitSet::with_capacity(len);
+    let mut b = FixedBitSet::with_capacity(len);
+    a.set_range(..a_end, true);
+    b.set_range(b_start.., true);
+    let ab = &a ^ &b;
+    for i in 0..b_start {
+        assert!(ab.contains(i));
+    }
+    for i in b_start..a_end {
+        assert!(!ab.contains(i));
+    }
+    for i in a_end..len {
+        assert!(ab.contains(i));
+    }
+    assert_eq!(a.len(), ab.len());
+}
+
+#[test]
+fn bitxor_first_smaller() {
+    let a_len = 113;
+    let b_len = 137;
+    let len = std::cmp::max(a_len, b_len);
+    let a_end = 97;
+    let b_start = 89;
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.set_range(..a_end, true);
+    b.set_range(b_start.., true);
+    let ab = &a ^ &b;
+    for i in 0..b_start {
+        assert!(ab.contains(i));
+    }
+    for i in b_start..a_end {
+        assert!(!ab.contains(i));
+    }
+    for i in a_end..len {
+        assert!(ab.contains(i));
+    }
+    assert_eq!(b.len(), ab.len());
+}
+
+#[test]
+fn bitxor_first_larger() {
+    let a_len = 173;
+    let b_len = 137;
+    let len = std::cmp::max(a_len, b_len);
+    let a_end = 107;
+    let b_start = 43;
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.set_range(..a_end, true);
+    b.set_range(b_start.., true);
+    let ab = &a ^ &b;
+    for i in 0..b_start {
+        assert!(ab.contains(i));
+    }
+    for i in b_start..a_end {
+        assert!(!ab.contains(i));
+    }
+    for i in a_end..b_len {
+        assert!(ab.contains(i));
+    }
+    for i in b_len..len {
+        assert!(!ab.contains(i));
+    }
+    assert_eq!(a.len(), ab.len());
+}
+
+#[test]
+fn bitand_assign_shorter() {
+    let a_ones: Vec<usize> = vec![2, 3, 7, 19, 31, 32, 37, 41, 43, 47, 71, 73, 101];
+    let b_ones: Vec<usize> = vec![2, 7, 8, 11, 23, 31, 32];
+    let a_and_b: Vec<usize> = vec![2, 7, 31, 32];
+    let mut a = a_ones.iter().cloned().collect::<FixedBitSet>();
+    let b = b_ones.iter().cloned().collect::<FixedBitSet>();
+    a &= b;
+    let res = a.ones().collect::<Vec<usize>>();
+
+    assert!(res == a_and_b);
+}
+
+#[test]
+fn bitand_assign_longer() {
+    let a_ones: Vec<usize> = vec![2, 7, 8, 11, 23, 31, 32];
+    let b_ones: Vec<usize> = vec![2, 3, 7, 19, 31, 32, 37, 41, 43, 47, 71, 73, 101];
+    let a_and_b: Vec<usize> = vec![2, 7, 31, 32];
+    let mut a = a_ones.iter().cloned().collect::<FixedBitSet>();
+    let b = b_ones.iter().cloned().collect::<FixedBitSet>();
+    a &= b;
+    let res = a.ones().collect::<Vec<usize>>();
+    assert!(res == a_and_b);
+}
+
+#[test]
+fn bitor_assign_shorter() {
+    let a_ones: Vec<usize> = vec![2, 3, 7, 19, 31, 32, 37, 41, 43, 47, 71, 73, 101];
+    let b_ones: Vec<usize> = vec![2, 7, 8, 11, 23, 31, 32];
+    let a_or_b: Vec<usize> = vec![2, 3, 7, 8, 11, 19, 23, 31, 32, 37, 41, 43, 47, 71, 73, 101];
+    let mut a = a_ones.iter().cloned().collect::<FixedBitSet>();
+    let b = b_ones.iter().cloned().collect::<FixedBitSet>();
+    a |= b;
+    let res = a.ones().collect::<Vec<usize>>();
+    assert!(res == a_or_b);
+}
+
+#[test]
+fn bitor_assign_longer() {
+    let a_ones: Vec<usize> = vec![2, 7, 8, 11, 23, 31, 32];
+    let b_ones: Vec<usize> = vec![2, 3, 7, 19, 31, 32, 37, 41, 43, 47, 71, 73, 101];
+    let a_or_b: Vec<usize> = vec![2, 3, 7, 8, 11, 19, 23, 31, 32, 37, 41, 43, 47, 71, 73, 101];
+    let mut a = a_ones.iter().cloned().collect::<FixedBitSet>();
+    let b = b_ones.iter().cloned().collect::<FixedBitSet>();
+    a |= b;
+    let res = a.ones().collect::<Vec<usize>>();
+    assert!(res == a_or_b);
+}
+
+#[test]
+fn bitxor_assign_shorter() {
+    let a_ones: Vec<usize> = vec![2, 3, 7, 19, 31, 32, 37, 41, 43, 47, 71, 73, 101];
+    let b_ones: Vec<usize> = vec![2, 7, 8, 11, 23, 31, 32];
+    let a_xor_b: Vec<usize> = vec![3, 8, 11, 19, 23, 37, 41, 43, 47, 71, 73, 101];
+    let mut a = a_ones.iter().cloned().collect::<FixedBitSet>();
+    let b = b_ones.iter().cloned().collect::<FixedBitSet>();
+    a ^= b;
+    let res = a.ones().collect::<Vec<usize>>();
+    assert!(res == a_xor_b);
+}
+
+#[test]
+fn bitxor_assign_longer() {
+    let a_ones: Vec<usize> = vec![2, 7, 8, 11, 23, 31, 32];
+    let b_ones: Vec<usize> = vec![2, 3, 7, 19, 31, 32, 37, 41, 43, 47, 71, 73, 101];
+    let a_xor_b: Vec<usize> = vec![3, 8, 11, 19, 23, 37, 41, 43, 47, 71, 73, 101];
+    let mut a = a_ones.iter().cloned().collect::<FixedBitSet>();
+    let b = b_ones.iter().cloned().collect::<FixedBitSet>();
+    a ^= b;
+    let res = a.ones().collect::<Vec<usize>>();
+    assert!(res == a_xor_b);
+}
+
+#[test]
+fn op_assign_ref() {
+    let mut a = FixedBitSet::with_capacity(8);
+    let b = FixedBitSet::with_capacity(8);
+
+    //check that all assign type operators work on references
+    a &= &b;
+    a |= &b;
+    a ^= &b;
+}
+
+#[test]
+fn subset_superset_shorter() {
+    let a_ones: Vec<usize> = vec![7, 31, 32, 63];
+    let b_ones: Vec<usize> = vec![2, 7, 19, 31, 32, 37, 41, 43, 47, 63, 73, 101];
+    let mut a = a_ones.iter().cloned().collect::<FixedBitSet>();
+    let b = b_ones.iter().cloned().collect::<FixedBitSet>();
+    assert!(a.is_subset(&b) && b.is_superset(&a));
+    a.insert(14);
+    assert!(!a.is_subset(&b) && !b.is_superset(&a));
+}
+
+#[test]
+fn subset_superset_longer() {
+    let a_len = 153;
+    let b_len = 75;
+    let a_ones: Vec<usize> = vec![7, 31, 32, 63];
+    let b_ones: Vec<usize> = vec![2, 7, 19, 31, 32, 37, 41, 43, 47, 63, 73];
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.extend(a_ones.iter().cloned());
+    b.extend(b_ones.iter().cloned());
+    assert!(a.is_subset(&b) && b.is_superset(&a));
+    a.insert(100);
+    assert!(!a.is_subset(&b) && !b.is_superset(&a));
+}
+
+#[test]
+fn is_disjoint_first_shorter() {
+    let a_len = 75;
+    let b_len = 153;
+    let a_ones: Vec<usize> = vec![2, 19, 32, 37, 41, 43, 47, 73];
+    let b_ones: Vec<usize> = vec![7, 23, 31, 63, 124];
+    let mut a = FixedBitSet::with_capacity(a_len);
+    let mut b = FixedBitSet::with_capacity(b_len);
+    a.extend(a_ones.iter().cloned());
+    b.extend(b_ones.iter().cloned());
+    assert!(a.is_disjoint(&b));
+    a.insert(63);
+    assert!(!a.is_disjoint(&b));
+}
+
+#[test]
+fn is_disjoint_first_longer() {
+    let a_ones: Vec<usize> = vec![2, 19, 32, 37, 41, 43, 47, 73, 101];
+    let b_ones: Vec<usize> = vec![7, 23, 31, 63];
+    let a = a_ones.iter().cloned().collect::<FixedBitSet>();
+    let mut b = b_ones.iter().cloned().collect::<FixedBitSet>();
+    assert!(a.is_disjoint(&b));
+    b.insert(2);
+    assert!(!a.is_disjoint(&b));
+}
+
+#[test]
+fn extend_on_empty() {
+    let items: Vec<usize> = vec![2, 3, 5, 7, 11, 13, 17, 19, 23, 27, 29, 31, 37, 167];
+    let mut fbs = FixedBitSet::with_capacity(0);
+    fbs.extend(items.iter().cloned());
+    let ones = fbs.ones().collect::<Vec<usize>>();
+    assert!(ones == items);
+}
+
+#[test]
+fn extend() {
+    let items: Vec<usize> = vec![2, 3, 5, 7, 11, 13, 17, 19, 23, 27, 29, 31, 37, 167];
+    let mut fbs = FixedBitSet::with_capacity(168);
+    let new: Vec<usize> = vec![7, 37, 67, 137];
+    for i in &new {
+        fbs.put(*i);
+    }
+
+    fbs.extend(items.iter().cloned());
+
+    let ones = fbs.ones().collect::<Vec<usize>>();
+    let expected = {
+        let mut tmp = items.clone();
+        tmp.extend(new);
+        tmp.sort();
+        tmp.dedup();
+        tmp
+    };
+
+    assert!(ones == expected);
+}
+
+#[test]
+fn from_iterator() {
+    let items: Vec<usize> = vec![0, 2, 4, 6, 8];
+    let fb = items.iter().cloned().collect::<FixedBitSet>();
+    for i in items {
+        assert!(fb.contains(i));
+    }
+    for i in vec![1, 3, 5, 7] {
+        assert!(!fb.contains(i));
+    }
+    assert_eq!(fb.len(), 9);
+}
+
+#[test]
+fn from_iterator_ones() {
+    let len = 257;
+    let mut fb = FixedBitSet::with_capacity(len);
+    for i in (0..len).filter(|i| i % 7 == 0) {
+        fb.put(i);
+    }
+    fb.put(len - 1);
+    let dup = fb.ones().collect::<FixedBitSet>();
+
+    assert_eq!(fb.len(), dup.len());
+    assert_eq!(
+        fb.ones().collect::<Vec<usize>>(),
+        dup.ones().collect::<Vec<usize>>()
+    );
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn binary_trait() {
+    let items: Vec<usize> = vec![1, 5, 7, 10, 14, 15];
+    let fb = items.iter().cloned().collect::<FixedBitSet>();
+
+    assert_eq!(format!("{:b}", fb), "0100010100100011");
+    assert_eq!(format!("{:#b}", fb), "0b0100010100100011");
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn display_trait() {
+    let len = 8;
+    let mut fb = FixedBitSet::with_capacity(len);
+
+    fb.put(4);
+    fb.put(2);
+
+    assert_eq!(format!("{}", fb), "00101000");
+    assert_eq!(format!("{:#}", fb), "0b00101000");
+}
+
+#[test]
+#[cfg(feature = "serde")]
+fn test_serialize() {
+    let mut fb = FixedBitSet::with_capacity(10);
+    fb.put(2);
+    fb.put(3);
+    fb.put(6);
+    fb.put(8);
+    let serialized = serde_json::to_string(&fb).unwrap();
+    assert_eq!(r#"{"data":[332],"length":10}"#, serialized);
+}
+
+#[test]
+fn test_is_clear() {
+    let mut fb = FixedBitSet::with_capacity(0);
+    assert!(fb.is_clear());
+
+    fb.grow(1);
+    assert!(fb.is_clear());
+
+    fb.put(0);
+    assert!(!fb.is_clear());
+
+    fb.grow(42);
+    fb.clear();
+    assert!(fb.is_clear());
+
+    fb.put(17);
+    fb.put(19);
+    assert!(!fb.is_clear());
+}
\ No newline at end of file
diff --git a/src/range.rs b/src/range.rs
new file mode 100644
index 0000000..aaa4896
--- /dev/null
+++ b/src/range.rs
@@ -0,0 +1,39 @@
+use std::ops::{
+    RangeFull,
+    RangeFrom,
+    RangeTo,
+    Range,
+};
+
+// Taken from https://github.com/bluss/odds/blob/master/src/range.rs.
+
+/// **IndexRange** is implemented by Rust's built-in range types, produced
+/// by range syntax like `..`, `a..`, `..b` or `c..d`.
+pub trait IndexRange<T=usize> {
+    #[inline]
+    /// Start index (inclusive)
+    fn start(&self) -> Option<T> { None }
+    #[inline]
+    /// End index (exclusive)
+    fn end(&self) -> Option<T> { None }
+}
+
+
+impl<T> IndexRange<T> for RangeFull {}
+
+impl<T: Copy> IndexRange<T> for RangeFrom<T> {
+    #[inline]
+    fn start(&self) -> Option<T> { Some(self.start) }
+}
+
+impl<T: Copy> IndexRange<T> for RangeTo<T> {
+    #[inline]
+    fn end(&self) -> Option<T> { Some(self.end) }
+}
+
+impl<T: Copy> IndexRange<T> for Range<T> {
+    #[inline]
+    fn start(&self) -> Option<T> { Some(self.start) }
+    #[inline]
+    fn end(&self) -> Option<T> { Some(self.end) }
+}