Enable a few rustfmt options:

* `imports_granularity = "Crate"`
* `comment_width = 100`
* `wrap_comments = true`

https://github.com/rust-lang/rustfmt/blob/master/Configurations.md#imports_granularity
https://github.com/rust-lang/rustfmt/blob/master/Configurations.md#comment_width
https://github.com/rust-lang/rustfmt/blob/master/Configurations.md#wrap_comments

Author: zeenix

.rustfmt.toml

@@ -0,0 +1,3 @@
+imports_granularity = "Crate"
+comment_width = 100
+wrap_comments = true

README.md

@@ -21,6 +21,15 @@ $ # run only for example histbuf tests
 $ cargo test histbuf --features serde
 ```
 
+# Formatting
+
+Like most Rust projects, we use `rustfmt` to keep the formatting of code consistent. However, we
+make use of cecertain options that are currently only available in the nightly version:
+
+```console
+$ cargo +nightly fmt --all
+```
+
 ## License
 
 Licensed under either of

src/c_string.rs

@@ -106,11 +106,12 @@ impl<const N: usize, LenT: LenType> CString<N, LenT> {
     ///
     /// # Safety
     ///
-    /// - The memory pointed to by `ptr` must contain a valid nul terminator at the
-    ///   end of the string.
-    /// - `ptr` must be valid for reads of bytes up to and including the nul terminator.
-    ///   This means in particular:
-    ///     - The entire memory range of this `CStr` must be contained within a single allocated object!
+    /// - The memory pointed to by `ptr` must contain a valid nul terminator at the end of the
+    ///   string.
+    /// - `ptr` must be valid for reads of bytes up to and including the nul terminator. This means
+    ///   in particular:
+    ///     - The entire memory range of this `CStr` must be contained within a single allocated
+    ///       object!
     ///     - `ptr` must be non-nul even for a zero-length `CStr`.
     ///
     /// # Example
@@ -190,7 +191,8 @@ impl<const N: usize, LenT: LenType> CString<N, LenT> {
 
         match CStr::from_bytes_with_nul(bytes) {
             Ok(_) => {
-                // SAFETY: A string is left in a valid state because appended bytes are nul-terminated.
+                // SAFETY: A string is left in a valid state because appended bytes are
+                // nul-terminated.
                 unsafe { self.extend_from_bytes_unchecked(bytes) }?;
 
                 Ok(())

src/deque.rs

@@ -33,14 +33,18 @@
 //! }
 //! ```
 
-use crate::vec::{OwnedVecStorage, VecStorage, VecStorageInner, ViewVecStorage};
-use crate::CapacityError;
-use core::cmp::Ordering;
-use core::fmt;
-use core::iter::FusedIterator;
-use core::marker::PhantomData;
-use core::mem::{ManuallyDrop, MaybeUninit};
-use core::{ptr, slice};
+use crate::{
+    vec::{OwnedVecStorage, VecStorage, VecStorageInner, ViewVecStorage},
+    CapacityError,
+};
+use core::{
+    cmp::Ordering,
+    fmt,
+    iter::FusedIterator,
+    marker::PhantomData,
+    mem::{ManuallyDrop, MaybeUninit},
+    ptr, slice,
+};
 
 #[cfg(feature = "zeroize")]
 use zeroize::Zeroize;
@@ -173,14 +177,16 @@ impl<T, const N: usize> Deque<T, N> {
 
     /// Returns the maximum number of elements the deque can hold.
     ///
-    /// This method is not available on a `DequeView`, use [`storage_capacity`](DequeInner::storage_capacity) instead.
+    /// This method is not available on a `DequeView`, use
+    /// [`storage_capacity`](DequeInner::storage_capacity) instead.
     pub const fn capacity(&self) -> usize {
         N
     }
 
     /// Returns the number of elements currently in the deque.
     ///
-    /// This method is not available on a `DequeView`, use [`storage_len`](DequeInner::storage_len) instead.
+    /// This method is not available on a `DequeView`, use [`storage_len`](DequeInner::storage_len)
+    /// instead.
     pub const fn len(&self) -> usize {
         if self.full {
             N
@@ -452,8 +458,8 @@ impl<T, S: VecStorage<T> + ?Sized> DequeInner<T, S> {
                         self.storage_capacity() - free,
                     );
 
-                    // because the deque wasn't contiguous, we know that `tail_len < self.len == slice.len()`,
-                    // so this will never panic.
+                    // because the deque wasn't contiguous, we know that `tail_len < self.len ==
+                    // slice.len()`, so this will never panic.
                     slice.rotate_left(back_len);
 
                     // the used part of the buffer now is `free..self.capacity()`, so set
@@ -465,7 +471,8 @@ impl<T, S: VecStorage<T> + ?Sized> DequeInner<T, S> {
                 // head is shorter so:
                 //  1. copy head backwards
                 //  2. rotate used part of the buffer
-                //  3. update head to point to the new beginning (which is the beginning of the buffer)
+                //  3. update head to point to the new beginning (which is the beginning of the
+                //     buffer)
 
                 unsafe {
                     // if there is no free space in the buffer, then the slices are already
@@ -483,8 +490,8 @@ impl<T, S: VecStorage<T> + ?Sized> DequeInner<T, S> {
                     // next to each other, all the elements in the range are initialized.
                     let slice: &mut [T] = slice::from_raw_parts_mut(buffer_ptr, len);
 
-                    // because the deque wasn't contiguous, we know that `head_len < self.len == slice.len()`
-                    // so this will never panic.
+                    // because the deque wasn't contiguous, we know that `head_len < self.len ==
+                    // slice.len()` so this will never panic.
                     slice.rotate_right(front_len);
 
                     // the used part of the buffer now is `0..self.len`, so set
@@ -844,11 +851,11 @@ impl<T, S: VecStorage<T> + ?Sized> DequeInner<T, S> {
         }
 
         // Safety:
-        // * Any slice passed to `drop_in_place` is valid; the second case has
-        //   `len <= front.len()` and returning on `len > self.storage_len()` ensures
-        //   `begin <= back.len()` in the first case
-        // * Deque front/back cursors are moved before calling `drop_in_place`,
-        //   so no value is dropped twice if `drop_in_place` panics
+        // * Any slice passed to `drop_in_place` is valid; the second case has `len <= front.len()`
+        //   and returning on `len > self.storage_len()` ensures `begin <= back.len()` in the first
+        //   case
+        // * Deque front/back cursors are moved before calling `drop_in_place`, so no value is
+        //   dropped twice if `drop_in_place` panics
         unsafe {
             // If new desired length is greater or equal, we don't need to act.
             if len >= self.storage_len() {
@@ -865,8 +872,9 @@ impl<T, S: VecStorage<T> + ?Sized> DequeInner<T, S> {
                 let drop_back = back.get_unchecked_mut(begin..) as *mut _;
 
                 // Self::to_physical_index returns the index `len` units _after_ the front cursor,
-                // meaning we can use it to find the decremented index for `back` for non-contiguous deques,
-                // as well as determine where the new "cap" for front needs to be placed for contiguous deques.
+                // meaning we can use it to find the decremented index for `back` for non-contiguous
+                // deques, as well as determine where the new "cap" for front needs
+                // to be placed for contiguous deques.
                 self.back = self.to_physical_index(len);
                 self.full = false;
 
@@ -880,8 +888,9 @@ impl<T, S: VecStorage<T> + ?Sized> DequeInner<T, S> {
                 self.back = self.to_physical_index(len);
                 self.full = false;
 
-                // If `drop_front` causes a panic, the Dropper will still be called to drop it's slice during unwinding.
-                // In either case, front will always be dropped before back.
+                // If `drop_front` causes a panic, the Dropper will still be called to drop it's
+                // slice during unwinding. In either case, front will always be
+                // dropped before back.
                 let _back_dropper = Dropper(&mut *drop_back);
                 ptr::drop_in_place(drop_front);
             }
@@ -970,7 +979,8 @@ impl<T, S: VecStorage<T> + ?Sized> DequeInner<T, S> {
             cur += 1;
             idx += 1;
         }
-        // Stage 2: Swap retained values into current idx, building a contiguous chunk from 0 to idx.
+        // Stage 2: Swap retained values into current idx, building a contiguous chunk from 0 to
+        // idx.
         while cur < len {
             let val = self
                 .get_mut(cur)

src/history_buf.rs

@@ -31,12 +31,7 @@
 //! assert_eq!(avg, 4);
 //! ```
 
-use core::fmt;
-use core::marker::PhantomData;
-use core::mem::MaybeUninit;
-use core::ops::Deref;
-use core::ptr;
-use core::slice;
+use core::{fmt, marker::PhantomData, mem::MaybeUninit, ops::Deref, ptr, slice};
 
 #[cfg(feature = "zeroize")]
 use zeroize::Zeroize;
@@ -51,18 +46,23 @@ mod storage {
     ///
     /// There's two implementations available:
     ///
-    /// - [`OwnedHistoryBufStorage`]: stores the data in an array `[T; N]` whose size is known at compile time.
+    /// - [`OwnedHistoryBufStorage`]: stores the data in an array `[T; N]` whose size is known at
+    ///   compile time.
     /// - [`ViewHistoryBufStorage`]: stores the data in an unsized `[T]`.
     ///
-    /// This allows [`HistoryBuf`] to be generic over either sized or unsized storage. The [`histbuf`]
-    /// module contains a [`HistoryBufInner`] struct that's generic on [`HistoryBufStorage`],
-    /// and two type aliases for convenience:
+    /// This allows [`HistoryBuf`] to be generic over either sized or unsized storage. The
+    /// [`histbuf`] module contains a [`HistoryBufInner`] struct that's generic on
+    /// [`HistoryBufStorage`], and two type aliases for convenience:
     ///
-    /// - [`HistoryBuf<T, N>`](super::HistoryBuf) = `HistoryBufInner<T, OwnedHistoryBufStorage<T, N>>`
-    /// - [`HistoryBufView<T>`](super::HistoryBufView) = `HistoryBufInner<T, ViewHistoryBufStorage<T>>`
+    /// - [`HistoryBuf<T, N>`](super::HistoryBuf) = `HistoryBufInner<T, OwnedHistoryBufStorage<T,
+    ///   N>>`
+    /// - [`HistoryBufView<T>`](super::HistoryBufView) = `HistoryBufInner<T,
+    ///   ViewHistoryBufStorage<T>>`
     ///
-    /// `HistoryBuf` can be unsized into `HistoryBufView`, either by unsizing coercions such as `&mut HistoryBuf -> &mut HistoryBufView` or
-    /// `Box<HistoryBuf> -> Box<HistoryBufView>`, or explicitly with [`.as_view()`](super::HistoryBuf::as_view) or [`.as_mut_view()`](super::HistoryBuf::as_mut_view).
+    /// `HistoryBuf` can be unsized into `HistoryBufView`, either by unsizing coercions such as
+    /// `&mut HistoryBuf -> &mut HistoryBufView` or `Box<HistoryBuf> -> Box<HistoryBufView>`, or
+    /// explicitly with [`.as_view()`](super::HistoryBuf::as_view) or
+    /// [`.as_mut_view()`](super::HistoryBuf::as_mut_view).
     ///
     /// This trait is sealed, so you cannot implement it for your own types. You can only use
     /// the implementations provided by this crate.
@@ -75,7 +75,8 @@ mod storage {
     pub trait HistoryBufStorage<T>: HistoryBufSealedStorage<T> {}
 
     pub trait HistoryBufSealedStorage<T> {
-        // part of the sealed trait so that no trait is publicly implemented by `OwnedHistoryBufStorage` besides `Storage`
+        // part of the sealed trait so that no trait is publicly implemented by
+        // `OwnedHistoryBufStorage` besides `Storage`
         fn borrow(&self) -> &[MaybeUninit<T>];
         fn borrow_mut(&mut self) -> &mut [MaybeUninit<T>];
         fn as_hist_buf_view(this: &HistoryBufInner<T, Self>) -> &HistoryBufView<T>
@@ -92,7 +93,8 @@ mod storage {
         pub(crate) buffer: T,
     }
 
-    /// Implementation of [`HistoryBufStorage`] that stores the data in an array `[T; N]` whose size is known at compile time.
+    /// Implementation of [`HistoryBufStorage`] that stores the data in an array `[T; N]` whose size
+    /// is known at compile time.
     pub type OwnedHistoryBufStorage<T, const N: usize> =
         HistoryBufStorageInner<[MaybeUninit<T>; N]>;
     /// Implementation of [`HistoryBufStorage`] that stores the data in an unsized `[T]`.
@@ -651,8 +653,10 @@ impl<T> DoubleEndedIterator for OldestOrdered<'_, T> {
 
 #[cfg(test)]
 mod tests {
-    use core::fmt::Debug;
-    use core::sync::atomic::{AtomicUsize, Ordering};
+    use core::{
+        fmt::Debug,
+        sync::atomic::{AtomicUsize, Ordering},
+    };
 
     use static_assertions::assert_not_impl_any;
 

src/index_map.rs

@@ -665,8 +665,8 @@ where
             match self.core.insert(self.hash_val, self.key, value) {
                 Insert::Success(inserted) => {
                     unsafe {
-                        // SAFETY: Already checked existence at instantiation and the only mutable reference
-                        // to the map is internally held.
+                        // SAFETY: Already checked existence at instantiation and the only mutable
+                        // reference to the map is internally held.
                         Ok(&mut (*self.core.entries.as_mut_ptr().add(inserted.index)).value)
                     }
                 }
@@ -1592,8 +1592,8 @@ impl<'a, K, V> Iterator for Values<'a, K, V> {
 
 /// A mutable iterator over the values of a [`IndexMap`].
 ///
-/// This `struct` is created by the [`values_mut`](IndexMap::values_mut) method on [`IndexMap`]. See its
-/// documentation for more.
+/// This `struct` is created by the [`values_mut`](IndexMap::values_mut) method on [`IndexMap`]. See
+/// its documentation for more.
 pub struct ValuesMut<'a, K, V> {
     iter: slice::IterMut<'a, Bucket<K, V>>,
 }

src/linear_map.rs

@@ -21,15 +21,17 @@ mod storage {
     /// - [`OwnedStorage`]: stores the data in an array whose size is known at compile time.
     /// - [`ViewStorage`]: stores the data in an unsized slice
     ///
-    /// This allows [`LinearMap`] to be generic over either sized or unsized storage. The [`linear_map`](super)
-    /// module contains a [`LinearMapInner`] struct that's generic on [`LinearMapStorage`],
-    /// and two type aliases for convenience:
+    /// This allows [`LinearMap`] to be generic over either sized or unsized storage. The
+    /// [`linear_map`](super) module contains a [`LinearMapInner`] struct that's generic on
+    /// [`LinearMapStorage`], and two type aliases for convenience:
     ///
     /// - [`LinearMap<N>`](crate::linear_map::LinearMap) = `LinearMapInner<OwnedStorage<u8, N>>`
     /// - [`LinearMapView<T>`](crate::linear_map::LinearMapView) = `LinearMapInner<ViewStorage<u8>>`
     ///
-    /// `LinearMap` can be unsized into `StrinsgView`, either by unsizing coercions such as `&mut LinearMap -> &mut LinearMapView` or
-    /// `Box<LinearMap> -> Box<LinearMapView>`, or explicitly with [`.as_view()`](crate::linear_map::LinearMap::as_view) or [`.as_mut_view()`](crate::linear_map::LinearMap::as_mut_view).
+    /// `LinearMap` can be unsized into `StrinsgView`, either by unsizing coercions such as `&mut
+    /// LinearMap -> &mut LinearMapView` or `Box<LinearMap> -> Box<LinearMapView>`, or
+    /// explicitly with [`.as_view()`](crate::linear_map::LinearMap::as_view) or
+    /// [`.as_mut_view()`](crate::linear_map::LinearMap::as_mut_view).
     ///
     /// This trait is sealed, so you cannot implement it for your own types. You can only use
     /// the implementations provided by this crate.
@@ -85,7 +87,8 @@ mod storage {
 }
 
 pub use storage::LinearMapStorage;
-/// Implementation of [`LinearMapStorage`] that stores the data in an array whose size is known at compile time.
+/// Implementation of [`LinearMapStorage`] that stores the data in an array whose size is known at
+/// compile time.
 pub type OwnedStorage<K, V, const N: usize> = OwnedVecStorage<(K, V), N>;
 /// Implementation of [`LinearMapStorage`] that stores the data in an unsized slice.
 pub type ViewStorage<K, V> = ViewVecStorage<(K, V)>;
@@ -590,7 +593,8 @@ where
 
 /// An iterator that moves out of a [`LinearMap`].
 ///
-/// This struct is created by calling the [`into_iter`](LinearMap::into_iter) method on [`LinearMap`].
+/// This struct is created by calling the [`into_iter`](LinearMap::into_iter) method on
+/// [`LinearMap`].
 pub struct IntoIter<K, V, const N: usize>
 where
     K: Eq,

src/mpmc.rs

@@ -69,7 +69,8 @@
 //!
 //! # Benchmark
 //!
-//! Measured on an ARM Cortex-M3 core running at 8 MHz and with zero flash wait cycles, compiled with `-C opt-level=z`:
+//! Measured on an ARM Cortex-M3 core running at 8 MHz and with zero flash wait cycles, compiled
+//! with `-C opt-level=z`:
 //!
 //! | Method                      | Time | N  |
 //! |:----------------------------|-----:|---:|
@@ -80,15 +81,14 @@
 //! | `Queue::<u8, 8>::dequeue()` |   53 |  1 |
 //! | `Queue::<u8, 8>::dequeue()` |   71 |  2 |
 //!
-//! - N denotes the number of interruptions. On Cortex-M, an interruption consists of an
-//!   interrupt handler preempting the would-be atomic section of the `enqueue`/`dequeue`
-//!   operation. Note that it does *not* matter if the higher priority handler uses the queue or
-//!   not.
+//! - N denotes the number of interruptions. On Cortex-M, an interruption consists of an interrupt
+//!   handler preempting the would-be atomic section of the `enqueue`/`dequeue` operation. Note that
+//!   it does *not* matter if the higher priority handler uses the queue or not.
 //! - All execution times are in clock cycles (1 clock cycle = 125 ns).
 //! - Execution time is *dependent* on `mem::size_of::<T>()`, as both operations include
 //!   `ptr::read::<T>()` or `ptr::write::<T>()` in their successful path.
-//! - The numbers reported correspond to the successful path, i.e. `dequeue` returning `Some`
-//!   and `enqueue` returning `Ok`.
+//! - The numbers reported correspond to the successful path, i.e. `dequeue` returning `Some` and
+//!   `enqueue` returning `Ok`.
 //!
 //! # References
 //!
@@ -146,7 +146,8 @@ pub type Queue<T, const N: usize> = QueueInner<T, OwnedStorage<N>>;
 
 /// A [`Queue`] with dynamic capacity.
 ///
-/// [`Queue`] coerces to `QueueView`. `QueueView` is `!Sized`, meaning it can only ever be used by reference.
+/// [`Queue`] coerces to `QueueView`. `QueueView` is `!Sized`, meaning it can only ever be used by
+/// reference.
 pub type QueueView<T> = QueueInner<T, ViewStorage>;
 
 impl<T, const N: usize> Queue<T, N> {
@@ -158,8 +159,8 @@ impl<T, const N: usize> Queue<T, N> {
     /// # Deprecation
     ///
     /// <div class="warning">
-    /// The current implementation of `mpmc` is marked as deprecated due to not being truly lock-free
-    /// </div>
+    /// The current implementation of `mpmc` is marked as deprecated due to not being truly
+    /// lock-free </div>
     ///
     /// If a thread is parked, or pre-empted for a long time by an higher-priority task
     /// during an `enqueue` or `dequeue` operation, it is possible that the queue ends-up
@@ -230,7 +231,8 @@ impl<T, S: Storage> QueueInner<T, S> {
     /// let view: &QueueView<u8> = queue.as_view();
     /// ```
     ///
-    /// It is often preferable to do the same through type coerction, since `Queue<T, N>` implements `Unsize<QueueView<T>>`:
+    /// It is often preferable to do the same through type coerction, since `Queue<T, N>` implements
+    /// `Unsize<QueueView<T>>`:
     ///
     /// ```rust
     /// # use heapless::mpmc::{Queue, QueueView};
@@ -251,7 +253,8 @@ impl<T, S: Storage> QueueInner<T, S> {
     /// let view: &mut QueueView<u8> = queue.as_mut_view();
     /// ```
     ///
-    /// It is often preferable to do the same through type coerction, since `Queue<T, N>` implements `Unsize<QueueView<T>>`:
+    /// It is often preferable to do the same through type coerction, since `Queue<T, N>` implements
+    /// `Unsize<QueueView<T>>`:
     ///
     /// ```rust
     /// # use heapless::mpmc::{Queue, QueueView};