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+#![deny(missing_docs)]
+
+//! `ThinVec` is exactly the same as `Vec`, except that it stores its `len` and `capacity` in the buffer
+//! it allocates.
+//!
+//! This makes the memory footprint of ThinVecs lower; notably in cases where space is reserved for
+//! a non-existence `ThinVec<T>`. So `Vec<ThinVec<T>>` and `Option<ThinVec<T>>::None` will waste less
+//! space. Being pointer-sized also means it can be passed/stored in registers.
+//!
+//! Of course, any actually constructed `ThinVec` will theoretically have a bigger allocation, but
+//! the fuzzy nature of allocators means that might not actually be the case.
+//!
+//! Properties of `Vec` that are preserved:
+//! * `ThinVec::new()` doesn't allocate (it points to a statically allocated singleton)
+//! * reallocation can be done in place
+//! * `size_of::<ThinVec<T>>()` == `size_of::<Option<ThinVec<T>>>()`
+//!
+//! Properties of `Vec` that aren't preserved:
+//! * `ThinVec<T>` can't ever be zero-cost roundtripped to a `Box<[T]>`, `String`, or `*mut T`
+//! * `from_raw_parts` doesn't exist
+//! * `ThinVec` currently doesn't bother to not-allocate for Zero Sized Types (e.g. `ThinVec<()>`),
+//! but it could be done if someone cared enough to implement it.
+//!
+//!
+//!
+//! # Gecko FFI
+//!
+//! If you enable the gecko-ffi feature, `ThinVec` will verbatim bridge with the nsTArray type in
+//! Gecko (Firefox). That is, `ThinVec` and nsTArray have identical layouts *but not ABIs*,
+//! so nsTArrays/ThinVecs an be natively manipulated by C++ and Rust, and ownership can be
+//! transferred across the FFI boundary (**IF YOU ARE CAREFUL, SEE BELOW!!**).
+//!
+//! While this feature is handy, it is also inherently dangerous to use because Rust and C++ do not
+//! know about each other. Specifically, this can be an issue with non-POD types (types which
+//! have destructors, move constructors, or are `!Copy`).
+//!
+//! ## Do Not Pass By Value
+//!
+//! The biggest thing to keep in mind is that **FFI functions cannot pass ThinVec/nsTArray
+//! by-value**. That is, these are busted APIs:
+//!
+//! ```rust,ignore
+//! // BAD WRONG
+//! extern fn process_data(data: ThinVec<u32>) { ... }
+//! // BAD WRONG
+//! extern fn get_data() -> ThinVec<u32> { ... }
+//! ```
+//!
+//! You must instead pass by-reference:
+//!
+//! ```rust
+//! # use thin_vec::*;
+//! # use std::mem;
+//!
+//! // Read-only access, ok!
+//! extern fn process_data(data: &ThinVec<u32>) {
+//! for val in data {
+//! println!("{}", val);
+//! }
+//! }
+//!
+//! // Replace with empty instance to take ownership, ok!
+//! extern fn consume_data(data: &mut ThinVec<u32>) {
+//! let owned = mem::replace(data, ThinVec::new());
+//! mem::drop(owned);
+//! }
+//!
+//! // Mutate input, ok!
+//! extern fn add_data(dataset: &mut ThinVec<u32>) {
+//! dataset.push(37);
+//! dataset.push(12);
+//! }
+//!
+//! // Return via out-param, usually ok!
+//! //
+//! // WARNING: output must be initialized! (Empty nsTArrays are free, so just do it!)
+//! extern fn get_data(output: &mut ThinVec<u32>) {
+//! *output = thin_vec![1, 2, 3, 4, 5];
+//! }
+//! ```
+//!
+//! Ignorable Explanation For Those Who Really Want To Know Why:
+//!
+//! > The fundamental issue is that Rust and C++ can't currently communicate about destructors, and
+//! > the semantics of C++ require destructors of function arguments to be run when the function
+//! > returns. Whether the callee or caller is responsible for this is also platform-specific, so
+//! > trying to hack around it manually would be messy.
+//! >
+//! > Also a type having a destructor changes its C++ ABI, because that type must actually exist
+//! > in memory (unlike a trivial struct, which is often passed in registers). We don't currently
+//! > have a way to communicate to Rust that this is happening, so even if we worked out the
+//! > destructor issue with say, MaybeUninit, it would still be a non-starter without some RFCs
+//! > to add explicit rustc support.
+//! >
+//! > Realistically, the best answer here is to have a "heavier" bindgen that can secretly
+//! > generate FFI glue so we can pass things "by value" and have it generate by-reference code
+//! > behind our back (like the cxx crate does). This would muddy up debugging/searchfox though.
+//!
+//! ## Types Should Be Trivially Relocatable
+//!
+//! Types in Rust are always trivially relocatable (unless suitably borrowed/[pinned][]/hidden).
+//! This means all Rust types are legal to relocate with a bitwise copy, you cannot provide
+//! copy or move constructors to execute when this happens, and the old location won't have its
+//! destructor run. This will cause problems for types which have a significant location
+//! (types that intrusively point into themselves or have their location registered with a service).
+//!
+//! While relocations are generally predictable if you're very careful, **you should avoid using
+//! types with significant locations with Rust FFI**.
+//!
+//! Specifically, `ThinVec` will trivially relocate its contents whenever it needs to reallocate its
+//! buffer to change its capacity. This is the default reallocation strategy for nsTArray, and is
+//! suitable for the vast majority of types. Just be aware of this limitation!
+//!
+//! ## Auto Arrays Are Dangerous
+//!
+//! `ThinVec` has *some* support for handling auto arrays which store their buffer on the stack,
+//! but this isn't well tested.
+//!
+//! Regardless of how much support we provide, Rust won't be aware of the buffer's limited lifetime,
+//! so standard auto array safety caveats apply about returning/storing them! `ThinVec` won't ever
+//! produce an auto array on its own, so this is only an issue for transferring an nsTArray into
+//! Rust.
+//!
+//! ## Other Issues
+//!
+//! Standard FFI caveats also apply:
+//!
+//! * Rust is more strict about POD types being initialized (use MaybeUninit if you must)
+//! * `ThinVec<T>` has no idea if the C++ version of `T` has move/copy/assign/delete overloads
+//! * `nsTArray<T>` has no idea if the Rust version of `T` has a Drop/Clone impl
+//! * C++ can do all sorts of unsound things that Rust can't catch
+//! * C++ and Rust don't agree on how zero-sized/empty types should be handled
+//!
+//! The gecko-ffi feature will not work if you aren't linking with code that has nsTArray
+//! defined. Specifically, we must share the symbol for nsTArray's empty singleton. You will get
+//! linking errors if that isn't defined.
+//!
+//! The gecko-ffi feature also limits `ThinVec` to the legacy behaviors of nsTArray. Most notably,
+//! nsTArray has a maximum capacity of i32::MAX (~2.1 billion items). Probably not an issue.
+//! Probably.
+//!
+//! [pinned]: https://doc.rust-lang.org/std/pin/index.html
+
+#![allow(clippy::comparison_chain, clippy::missing_safety_doc)]
+
+use std::alloc::*;
+use std::borrow::*;
+use std::cmp::*;
+use std::convert::TryFrom;
+use std::convert::TryInto;
+use std::hash::*;
+use std::iter::FromIterator;
+use std::marker::PhantomData;
+use std::ops::Bound;
+use std::ops::{Deref, DerefMut, RangeBounds};
+use std::ptr::NonNull;
+use std::slice::IterMut;
+use std::{fmt, io, mem, ptr, slice};
+
+use impl_details::*;
+
+// modules: a simple way to cfg a whole bunch of impl details at once
+
+#[cfg(not(feature = "gecko-ffi"))]
+mod impl_details {
+ pub type SizeType = usize;
+ pub const MAX_CAP: usize = !0;
+
+ #[inline(always)]
+ pub fn assert_size(x: usize) -> SizeType {
+ x
+ }
+}
+
+#[cfg(feature = "gecko-ffi")]
+mod impl_details {
+ // Support for briding a gecko nsTArray verbatim into a ThinVec.
+ //
+ // `ThinVec` can't see copy/move/delete implementations
+ // from C++
+ //
+ // The actual layout of an nsTArray is:
+ //
+ // ```cpp
+ // struct {
+ // uint32_t mLength;
+ // uint32_t mCapacity: 31;
+ // uint32_t mIsAutoArray: 1;
+ // }
+ // ```
+ //
+ // Rust doesn't natively support bit-fields, so we manually mask
+ // and shift the bit. When the "auto" bit is set, the header and buffer
+ // are actually on the stack, meaning the `ThinVec` pointer-to-header
+ // is essentially an "owned borrow", and therefore dangerous to handle.
+ // There are no safety guards for this situation.
+ //
+ // On little-endian platforms, the auto bit will be the high-bit of
+ // our capacity u32. On big-endian platforms, it will be the low bit.
+ // Hence we need some platform-specific CFGs for the necessary masking/shifting.
+ //
+ // `ThinVec` won't ever construct an auto array. They only happen when
+ // bridging from C++. This means we don't need to ever set/preserve the bit.
+ // We just need to be able to read and handle it if it happens to be there.
+ //
+ // Handling the auto bit mostly just means not freeing/reallocating the buffer.
+
+ pub type SizeType = u32;
+
+ pub const MAX_CAP: usize = i32::max_value() as usize;
+
+ // Little endian: the auto bit is the high bit, and the capacity is
+ // verbatim. So we just need to mask off the high bit. Note that
+ // this masking is unnecessary when packing, because assert_size
+ // guards against the high bit being set.
+ #[cfg(target_endian = "little")]
+ pub fn pack_capacity(cap: SizeType) -> SizeType {
+ cap as SizeType
+ }
+ #[cfg(target_endian = "little")]
+ pub fn unpack_capacity(cap: SizeType) -> usize {
+ (cap as usize) & !(1 << 31)
+ }
+ #[cfg(target_endian = "little")]
+ pub fn is_auto(cap: SizeType) -> bool {
+ (cap & (1 << 31)) != 0
+ }
+
+ // Big endian: the auto bit is the low bit, and the capacity is
+ // shifted up one bit. Masking out the auto bit is unnecessary,
+ // as rust shifts always shift in 0's for unsigned integers.
+ #[cfg(target_endian = "big")]
+ pub fn pack_capacity(cap: SizeType) -> SizeType {
+ (cap as SizeType) << 1
+ }
+ #[cfg(target_endian = "big")]
+ pub fn unpack_capacity(cap: SizeType) -> usize {
+ (cap >> 1) as usize
+ }
+ #[cfg(target_endian = "big")]
+ pub fn is_auto(cap: SizeType) -> bool {
+ (cap & 1) != 0
+ }
+
+ #[inline]
+ pub fn assert_size(x: usize) -> SizeType {
+ if x > MAX_CAP as usize {
+ panic!("nsTArray size may not exceed the capacity of a 32-bit sized int");
+ }
+ x as SizeType
+ }
+}
+
+// The header of a ThinVec.
+//
+// The _cap can be a bitfield, so use accessors to avoid trouble.
+//
+// In "real" gecko-ffi mode, the empty singleton will be aligned
+// to 8 by gecko. But in tests we have to provide the singleton
+// ourselves, and Rust makes it hard to "just" align a static.
+// To avoid messing around with a wrapper type around the
+// singleton *just* for tests, we just force all headers to be
+// aligned to 8 in this weird "zombie" gecko mode.
+//
+// This shouldn't affect runtime layout (padding), but it will
+// result in us asking the allocator to needlessly overalign
+// non-empty ThinVecs containing align < 8 types in
+// zombie-mode, but not in "real" geck-ffi mode. Minor.
+#[cfg_attr(all(feature = "gecko-ffi", any(test, miri)), repr(align(8)))]
+#[repr(C)]
+struct Header {
+ _len: SizeType,
+ _cap: SizeType,
+}
+
+impl Header {
+ #[inline]
+ #[allow(clippy::unnecessary_cast)]
+ fn len(&self) -> usize {
+ self._len as usize
+ }
+
+ #[inline]
+ fn set_len(&mut self, len: usize) {
+ self._len = assert_size(len);
+ }
+}
+
+#[cfg(feature = "gecko-ffi")]
+impl Header {
+ fn cap(&self) -> usize {
+ unpack_capacity(self._cap)
+ }
+
+ fn set_cap(&mut self, cap: usize) {
+ // debug check that our packing is working
+ debug_assert_eq!(unpack_capacity(pack_capacity(cap as SizeType)), cap);
+ // FIXME: this assert is busted because it reads uninit memory
+ // debug_assert!(!self.uses_stack_allocated_buffer());
+
+ // NOTE: this always stores a cleared auto bit, because set_cap
+ // is only invoked by Rust, and Rust doesn't create auto arrays.
+ self._cap = pack_capacity(assert_size(cap));
+ }
+
+ fn uses_stack_allocated_buffer(&self) -> bool {
+ is_auto(self._cap)
+ }
+}
+
+#[cfg(not(feature = "gecko-ffi"))]
+impl Header {
+ #[allow(clippy::unnecessary_cast)]
+ fn cap(&self) -> usize {
+ self._cap as usize
+ }
+
+ fn set_cap(&mut self, cap: usize) {
+ self._cap = assert_size(cap);
+ }
+}
+
+/// Singleton that all empty collections share.
+/// Note: can't store non-zero ZSTs, we allocate in that case. We could
+/// optimize everything to not do that (basically, make ptr == len and branch
+/// on size == 0 in every method), but it's a bunch of work for something that
+/// doesn't matter much.
+#[cfg(any(not(feature = "gecko-ffi"), test, miri))]
+static EMPTY_HEADER: Header = Header { _len: 0, _cap: 0 };
+
+#[cfg(all(feature = "gecko-ffi", not(test), not(miri)))]
+extern "C" {
+ #[link_name = "sEmptyTArrayHeader"]
+ static EMPTY_HEADER: Header;
+}
+
+// Utils for computing layouts of allocations
+
+/// Gets the size necessary to allocate a `ThinVec<T>` with the give capacity.
+///
+/// # Panics
+///
+/// This will panic if isize::MAX is overflowed at any point.
+fn alloc_size<T>(cap: usize) -> usize {
+ // Compute "real" header size with pointer math
+ //
+ // We turn everything into isizes here so that we can catch isize::MAX overflow,
+ // we never want to allow allocations larger than that!
+ let header_size = mem::size_of::<Header>() as isize;
+ let padding = padding::<T>() as isize;
+
+ let data_size = if mem::size_of::<T>() == 0 {
+ // If we're allocating an array for ZSTs we need a header/padding but no actual
+ // space for items, so we don't care about the capacity that was requested!
+ 0
+ } else {
+ let cap: isize = cap.try_into().expect("capacity overflow");
+ let elem_size = mem::size_of::<T>() as isize;
+ elem_size.checked_mul(cap).expect("capacity overflow")
+ };
+
+ let final_size = data_size
+ .checked_add(header_size + padding)
+ .expect("capacity overflow");
+
+ // Ok now we can turn it back into a usize (don't need to worry about negatives)
+ final_size as usize
+}
+
+/// Gets the padding necessary for the array of a `ThinVec<T>`
+fn padding<T>() -> usize {
+ let alloc_align = alloc_align::<T>();
+ let header_size = mem::size_of::<Header>();
+
+ if alloc_align > header_size {
+ if cfg!(feature = "gecko-ffi") {
+ panic!(
+ "nsTArray does not handle alignment above > {} correctly",
+ header_size
+ );
+ }
+ alloc_align - header_size
+ } else {
+ 0
+ }
+}
+
+/// Gets the align necessary to allocate a `ThinVec<T>`
+fn alloc_align<T>() -> usize {
+ max(mem::align_of::<T>(), mem::align_of::<Header>())
+}
+
+/// Gets the layout necessary to allocate a `ThinVec<T>`
+///
+/// # Panics
+///
+/// Panics if the required size overflows `isize::MAX`.
+fn layout<T>(cap: usize) -> Layout {
+ unsafe { Layout::from_size_align_unchecked(alloc_size::<T>(cap), alloc_align::<T>()) }
+}
+
+/// Allocates a header (and array) for a `ThinVec<T>` with the given capacity.
+///
+/// # Panics
+///
+/// Panics if the required size overflows `isize::MAX`.
+fn header_with_capacity<T>(cap: usize) -> NonNull<Header> {
+ debug_assert!(cap > 0);
+ unsafe {
+ let layout = layout::<T>(cap);
+ let header = alloc(layout) as *mut Header;
+
+ if header.is_null() {
+ handle_alloc_error(layout)
+ }
+
+ // "Infinite" capacity for zero-sized types:
+ (*header).set_cap(if mem::size_of::<T>() == 0 {
+ MAX_CAP
+ } else {
+ cap
+ });
+ (*header).set_len(0);
+
+ NonNull::new_unchecked(header)
+ }
+}
+
+/// See the crate's top level documentation for a description of this type.
+#[repr(C)]
+pub struct ThinVec<T> {
+ ptr: NonNull<Header>,
+ boo: PhantomData<T>,
+}
+
+unsafe impl<T: Sync> Sync for ThinVec<T> {}
+unsafe impl<T: Send> Send for ThinVec<T> {}
+
+/// Creates a `ThinVec` containing the arguments.
+///
+// A hack to avoid linking problems with `cargo test --features=gecko-ffi`.
+#[cfg_attr(not(feature = "gecko-ffi"), doc = "```")]
+#[cfg_attr(feature = "gecko-ffi", doc = "```ignore")]
+/// #[macro_use] extern crate thin_vec;
+///
+/// fn main() {
+/// let v = thin_vec![1, 2, 3];
+/// assert_eq!(v.len(), 3);
+/// assert_eq!(v[0], 1);
+/// assert_eq!(v[1], 2);
+/// assert_eq!(v[2], 3);
+///
+/// let v = thin_vec![1; 3];
+/// assert_eq!(v, [1, 1, 1]);
+/// }
+/// ```
+#[macro_export]
+macro_rules! thin_vec {
+ (@UNIT $($t:tt)*) => (());
+
+ ($elem:expr; $n:expr) => ({
+ let mut vec = $crate::ThinVec::new();
+ vec.resize($n, $elem);
+ vec
+ });
+ () => {$crate::ThinVec::new()};
+ ($($x:expr),*) => ({
+ let len = [$(thin_vec!(@UNIT $x)),*].len();
+ let mut vec = $crate::ThinVec::with_capacity(len);
+ $(vec.push($x);)*
+ vec
+ });
+ ($($x:expr,)*) => (thin_vec![$($x),*]);
+}
+
+impl<T> ThinVec<T> {
+ /// Creates a new empty ThinVec.
+ ///
+ /// This will not allocate.
+ pub fn new() -> ThinVec<T> {
+ ThinVec::with_capacity(0)
+ }
+
+ /// Constructs a new, empty `ThinVec<T>` with at least the specified capacity.
+ ///
+ /// The vector will be able to hold at least `capacity` elements without
+ /// reallocating. This method is allowed to allocate for more elements than
+ /// `capacity`. If `capacity` is 0, the vector will not allocate.
+ ///
+ /// It is important to note that although the returned vector has the
+ /// minimum *capacity* specified, the vector will have a zero *length*.
+ ///
+ /// If it is important to know the exact allocated capacity of a `ThinVec`,
+ /// always use the [`capacity`] method after construction.
+ ///
+ /// **NOTE**: unlike `Vec`, `ThinVec` **MUST** allocate once to keep track of non-zero
+ /// lengths. As such, we cannot provide the same guarantees about ThinVecs
+ /// of ZSTs not allocating. However the allocation never needs to be resized
+ /// to add more ZSTs, since the underlying array is still length 0.
+ ///
+ /// [Capacity and reallocation]: #capacity-and-reallocation
+ /// [`capacity`]: Vec::capacity
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::ThinVec;
+ ///
+ /// let mut vec = ThinVec::with_capacity(10);
+ ///
+ /// // The vector contains no items, even though it has capacity for more
+ /// assert_eq!(vec.len(), 0);
+ /// assert!(vec.capacity() >= 10);
+ ///
+ /// // These are all done without reallocating...
+ /// for i in 0..10 {
+ /// vec.push(i);
+ /// }
+ /// assert_eq!(vec.len(), 10);
+ /// assert!(vec.capacity() >= 10);
+ ///
+ /// // ...but this may make the vector reallocate
+ /// vec.push(11);
+ /// assert_eq!(vec.len(), 11);
+ /// assert!(vec.capacity() >= 11);
+ ///
+ /// // A vector of a zero-sized type will always over-allocate, since no
+ /// // space is needed to store the actual elements.
+ /// let vec_units = ThinVec::<()>::with_capacity(10);
+ ///
+ /// // Only true **without** the gecko-ffi feature!
+ /// // assert_eq!(vec_units.capacity(), usize::MAX);
+ /// ```
+ pub fn with_capacity(cap: usize) -> ThinVec<T> {
+ // `padding` contains ~static assertions against types that are
+ // incompatible with the current feature flags. We also call it to
+ // invoke these assertions when getting a pointer to the `ThinVec`
+ // contents, but since we also get a pointer to the contents in the
+ // `Drop` impl, trippng an assertion along that code path causes a
+ // double panic. We duplicate the assertion here so that it is
+ // testable,
+ let _ = padding::<T>();
+
+ if cap == 0 {
+ unsafe {
+ ThinVec {
+ ptr: NonNull::new_unchecked(&EMPTY_HEADER as *const Header as *mut Header),
+ boo: PhantomData,
+ }
+ }
+ } else {
+ ThinVec {
+ ptr: header_with_capacity::<T>(cap),
+ boo: PhantomData,
+ }
+ }
+ }
+
+ // Accessor conveniences
+
+ fn ptr(&self) -> *mut Header {
+ self.ptr.as_ptr()
+ }
+ fn header(&self) -> &Header {
+ unsafe { self.ptr.as_ref() }
+ }
+ fn data_raw(&self) -> *mut T {
+ // `padding` contains ~static assertions against types that are
+ // incompatible with the current feature flags. Even if we don't
+ // care about its result, we should always call it before getting
+ // a data pointer to guard against invalid types!
+ let padding = padding::<T>();
+
+ // Although we ensure the data array is aligned when we allocate,
+ // we can't do that with the empty singleton. So when it might not
+ // be properly aligned, we substitute in the NonNull::dangling
+ // which *is* aligned.
+ //
+ // To minimize dynamic branches on `cap` for all accesses
+ // to the data, we include this guard which should only involve
+ // compile-time constants. Ideally this should result in the branch
+ // only be included for types with excessive alignment.
+ let empty_header_is_aligned = if cfg!(feature = "gecko-ffi") {
+ // in gecko-ffi mode `padding` will ensure this under
+ // the assumption that the header has size 8 and the
+ // static empty singleton is aligned to 8.
+ true
+ } else {
+ // In non-gecko-ffi mode, the empty singleton is just
+ // naturally aligned to the Header. If the Header is at
+ // least as aligned as T *and* the padding would have
+ // been 0, then one-past-the-end of the empty singleton
+ // *is* a valid data pointer and we can remove the
+ // `dangling` special case.
+ mem::align_of::<Header>() >= mem::align_of::<T>() && padding == 0
+ };
+
+ unsafe {
+ if !empty_header_is_aligned && self.header().cap() == 0 {
+ NonNull::dangling().as_ptr()
+ } else {
+ // This could technically result in overflow, but padding
+ // would have to be absurdly large for this to occur.
+ let header_size = mem::size_of::<Header>();
+ let ptr = self.ptr.as_ptr() as *mut u8;
+ ptr.add(header_size + padding) as *mut T
+ }
+ }
+ }
+
+ // This is unsafe when the header is EMPTY_HEADER.
+ unsafe fn header_mut(&mut self) -> &mut Header {
+ &mut *self.ptr()
+ }
+
+ /// Returns the number of elements in the vector, also referred to
+ /// as its 'length'.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let a = thin_vec![1, 2, 3];
+ /// assert_eq!(a.len(), 3);
+ /// ```
+ pub fn len(&self) -> usize {
+ self.header().len()
+ }
+
+ /// Returns `true` if the vector contains no elements.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::ThinVec;
+ ///
+ /// let mut v = ThinVec::new();
+ /// assert!(v.is_empty());
+ ///
+ /// v.push(1);
+ /// assert!(!v.is_empty());
+ /// ```
+ pub fn is_empty(&self) -> bool {
+ self.len() == 0
+ }
+
+ /// Returns the number of elements the vector can hold without
+ /// reallocating.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::ThinVec;
+ ///
+ /// let vec: ThinVec<i32> = ThinVec::with_capacity(10);
+ /// assert_eq!(vec.capacity(), 10);
+ /// ```
+ pub fn capacity(&self) -> usize {
+ self.header().cap()
+ }
+
+ /// Forces the length of the vector to `new_len`.
+ ///
+ /// This is a low-level operation that maintains none of the normal
+ /// invariants of the type. Normally changing the length of a vector
+ /// is done using one of the safe operations instead, such as
+ /// [`truncate`], [`resize`], [`extend`], or [`clear`].
+ ///
+ /// [`truncate`]: ThinVec::truncate
+ /// [`resize`]: ThinVec::resize
+ /// [`extend`]: ThinVec::extend
+ /// [`clear`]: ThinVec::clear
+ ///
+ /// # Safety
+ ///
+ /// - `new_len` must be less than or equal to [`capacity()`].
+ /// - The elements at `old_len..new_len` must be initialized.
+ ///
+ /// [`capacity()`]: ThinVec::capacity
+ ///
+ /// # Examples
+ ///
+ /// This method can be useful for situations in which the vector
+ /// is serving as a buffer for other code, particularly over FFI:
+ ///
+ /// ```no_run
+ /// use thin_vec::ThinVec;
+ ///
+ /// # // This is just a minimal skeleton for the doc example;
+ /// # // don't use this as a starting point for a real library.
+ /// # pub struct StreamWrapper { strm: *mut std::ffi::c_void }
+ /// # const Z_OK: i32 = 0;
+ /// # extern "C" {
+ /// # fn deflateGetDictionary(
+ /// # strm: *mut std::ffi::c_void,
+ /// # dictionary: *mut u8,
+ /// # dictLength: *mut usize,
+ /// # ) -> i32;
+ /// # }
+ /// # impl StreamWrapper {
+ /// pub fn get_dictionary(&self) -> Option<ThinVec<u8>> {
+ /// // Per the FFI method's docs, "32768 bytes is always enough".
+ /// let mut dict = ThinVec::with_capacity(32_768);
+ /// let mut dict_length = 0;
+ /// // SAFETY: When `deflateGetDictionary` returns `Z_OK`, it holds that:
+ /// // 1. `dict_length` elements were initialized.
+ /// // 2. `dict_length` <= the capacity (32_768)
+ /// // which makes `set_len` safe to call.
+ /// unsafe {
+ /// // Make the FFI call...
+ /// let r = deflateGetDictionary(self.strm, dict.as_mut_ptr(), &mut dict_length);
+ /// if r == Z_OK {
+ /// // ...and update the length to what was initialized.
+ /// dict.set_len(dict_length);
+ /// Some(dict)
+ /// } else {
+ /// None
+ /// }
+ /// }
+ /// }
+ /// # }
+ /// ```
+ ///
+ /// While the following example is sound, there is a memory leak since
+ /// the inner vectors were not freed prior to the `set_len` call:
+ ///
+ /// ```no_run
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![thin_vec![1, 0, 0],
+ /// thin_vec![0, 1, 0],
+ /// thin_vec![0, 0, 1]];
+ /// // SAFETY:
+ /// // 1. `old_len..0` is empty so no elements need to be initialized.
+ /// // 2. `0 <= capacity` always holds whatever `capacity` is.
+ /// unsafe {
+ /// vec.set_len(0);
+ /// }
+ /// ```
+ ///
+ /// Normally, here, one would use [`clear`] instead to correctly drop
+ /// the contents and thus not leak memory.
+ pub unsafe fn set_len(&mut self, len: usize) {
+ if self.is_singleton() {
+ // A prerequisite of `Vec::set_len` is that `new_len` must be
+ // less than or equal to capacity(). The same applies here.
+ assert!(len == 0, "invalid set_len({}) on empty ThinVec", len);
+ } else {
+ self.header_mut().set_len(len)
+ }
+ }
+
+ // For internal use only, when setting the length and it's known to be the non-singleton.
+ unsafe fn set_len_non_singleton(&mut self, len: usize) {
+ self.header_mut().set_len(len)
+ }
+
+ /// Appends an element to the back of a collection.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![1, 2];
+ /// vec.push(3);
+ /// assert_eq!(vec, [1, 2, 3]);
+ /// ```
+ pub fn push(&mut self, val: T) {
+ let old_len = self.len();
+ if old_len == self.capacity() {
+ self.reserve(1);
+ }
+ unsafe {
+ ptr::write(self.data_raw().add(old_len), val);
+ self.set_len_non_singleton(old_len + 1);
+ }
+ }
+
+ /// Removes the last element from a vector and returns it, or [`None`] if it
+ /// is empty.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![1, 2, 3];
+ /// assert_eq!(vec.pop(), Some(3));
+ /// assert_eq!(vec, [1, 2]);
+ /// ```
+ pub fn pop(&mut self) -> Option<T> {
+ let old_len = self.len();
+ if old_len == 0 {
+ return None;
+ }
+
+ unsafe {
+ self.set_len_non_singleton(old_len - 1);
+ Some(ptr::read(self.data_raw().add(old_len - 1)))
+ }
+ }
+
+ /// Inserts an element at position `index` within the vector, shifting all
+ /// elements after it to the right.
+ ///
+ /// # Panics
+ ///
+ /// Panics if `index > len`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![1, 2, 3];
+ /// vec.insert(1, 4);
+ /// assert_eq!(vec, [1, 4, 2, 3]);
+ /// vec.insert(4, 5);
+ /// assert_eq!(vec, [1, 4, 2, 3, 5]);
+ /// ```
+ pub fn insert(&mut self, idx: usize, elem: T) {
+ let old_len = self.len();
+
+ assert!(idx <= old_len, "Index out of bounds");
+ if old_len == self.capacity() {
+ self.reserve(1);
+ }
+ unsafe {
+ let ptr = self.data_raw();
+ ptr::copy(ptr.add(idx), ptr.add(idx + 1), old_len - idx);
+ ptr::write(ptr.add(idx), elem);
+ self.set_len_non_singleton(old_len + 1);
+ }
+ }
+
+ /// Removes and returns the element at position `index` within the vector,
+ /// shifting all elements after it to the left.
+ ///
+ /// Note: Because this shifts over the remaining elements, it has a
+ /// worst-case performance of *O*(*n*). If you don't need the order of elements
+ /// to be preserved, use [`swap_remove`] instead. If you'd like to remove
+ /// elements from the beginning of the `ThinVec`, consider using `std::collections::VecDeque`.
+ ///
+ /// [`swap_remove`]: ThinVec::swap_remove
+ ///
+ /// # Panics
+ ///
+ /// Panics if `index` is out of bounds.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut v = thin_vec![1, 2, 3];
+ /// assert_eq!(v.remove(1), 2);
+ /// assert_eq!(v, [1, 3]);
+ /// ```
+ pub fn remove(&mut self, idx: usize) -> T {
+ let old_len = self.len();
+
+ assert!(idx < old_len, "Index out of bounds");
+
+ unsafe {
+ self.set_len_non_singleton(old_len - 1);
+ let ptr = self.data_raw();
+ let val = ptr::read(self.data_raw().add(idx));
+ ptr::copy(ptr.add(idx + 1), ptr.add(idx), old_len - idx - 1);
+ val
+ }
+ }
+
+ /// Removes an element from the vector and returns it.
+ ///
+ /// The removed element is replaced by the last element of the vector.
+ ///
+ /// This does not preserve ordering, but is *O*(1).
+ /// If you need to preserve the element order, use [`remove`] instead.
+ ///
+ /// [`remove`]: ThinVec::remove
+ ///
+ /// # Panics
+ ///
+ /// Panics if `index` is out of bounds.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut v = thin_vec!["foo", "bar", "baz", "qux"];
+ ///
+ /// assert_eq!(v.swap_remove(1), "bar");
+ /// assert_eq!(v, ["foo", "qux", "baz"]);
+ ///
+ /// assert_eq!(v.swap_remove(0), "foo");
+ /// assert_eq!(v, ["baz", "qux"]);
+ /// ```
+ pub fn swap_remove(&mut self, idx: usize) -> T {
+ let old_len = self.len();
+
+ assert!(idx < old_len, "Index out of bounds");
+
+ unsafe {
+ let ptr = self.data_raw();
+ ptr::swap(ptr.add(idx), ptr.add(old_len - 1));
+ self.set_len_non_singleton(old_len - 1);
+ ptr::read(ptr.add(old_len - 1))
+ }
+ }
+
+ /// Shortens the vector, keeping the first `len` elements and dropping
+ /// the rest.
+ ///
+ /// If `len` is greater than the vector's current length, this has no
+ /// effect.
+ ///
+ /// The [`drain`] method can emulate `truncate`, but causes the excess
+ /// elements to be returned instead of dropped.
+ ///
+ /// Note that this method has no effect on the allocated capacity
+ /// of the vector.
+ ///
+ /// # Examples
+ ///
+ /// Truncating a five element vector to two elements:
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![1, 2, 3, 4, 5];
+ /// vec.truncate(2);
+ /// assert_eq!(vec, [1, 2]);
+ /// ```
+ ///
+ /// No truncation occurs when `len` is greater than the vector's current
+ /// length:
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![1, 2, 3];
+ /// vec.truncate(8);
+ /// assert_eq!(vec, [1, 2, 3]);
+ /// ```
+ ///
+ /// Truncating when `len == 0` is equivalent to calling the [`clear`]
+ /// method.
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![1, 2, 3];
+ /// vec.truncate(0);
+ /// assert_eq!(vec, []);
+ /// ```
+ ///
+ /// [`clear`]: ThinVec::clear
+ /// [`drain`]: ThinVec::drain
+ pub fn truncate(&mut self, len: usize) {
+ unsafe {
+ // drop any extra elements
+ while len < self.len() {
+ // decrement len before the drop_in_place(), so a panic on Drop
+ // doesn't re-drop the just-failed value.
+ let new_len = self.len() - 1;
+ self.set_len_non_singleton(new_len);
+ ptr::drop_in_place(self.data_raw().add(new_len));
+ }
+ }
+ }
+
+ /// Clears the vector, removing all values.
+ ///
+ /// Note that this method has no effect on the allocated capacity
+ /// of the vector.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut v = thin_vec![1, 2, 3];
+ /// v.clear();
+ /// assert!(v.is_empty());
+ /// ```
+ pub fn clear(&mut self) {
+ unsafe {
+ ptr::drop_in_place(&mut self[..]);
+ self.set_len(0); // could be the singleton
+ }
+ }
+
+ /// Extracts a slice containing the entire vector.
+ ///
+ /// Equivalent to `&s[..]`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ /// use std::io::{self, Write};
+ /// let buffer = thin_vec![1, 2, 3, 5, 8];
+ /// io::sink().write(buffer.as_slice()).unwrap();
+ /// ```
+ pub fn as_slice(&self) -> &[T] {
+ unsafe { slice::from_raw_parts(self.data_raw(), self.len()) }
+ }
+
+ /// Extracts a mutable slice of the entire vector.
+ ///
+ /// Equivalent to `&mut s[..]`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ /// use std::io::{self, Read};
+ /// let mut buffer = vec![0; 3];
+ /// io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap();
+ /// ```
+ pub fn as_mut_slice(&mut self) -> &mut [T] {
+ unsafe { slice::from_raw_parts_mut(self.data_raw(), self.len()) }
+ }
+
+ /// Reserve capacity for at least `additional` more elements to be inserted.
+ ///
+ /// May reserve more space than requested, to avoid frequent reallocations.
+ ///
+ /// Panics if the new capacity overflows `usize`.
+ ///
+ /// Re-allocates only if `self.capacity() < self.len() + additional`.
+ #[cfg(not(feature = "gecko-ffi"))]
+ pub fn reserve(&mut self, additional: usize) {
+ let len = self.len();
+ let old_cap = self.capacity();
+ let min_cap = len.checked_add(additional).expect("capacity overflow");
+ if min_cap <= old_cap {
+ return;
+ }
+ // Ensure the new capacity is at least double, to guarantee exponential growth.
+ let double_cap = if old_cap == 0 {
+ // skip to 4 because tiny ThinVecs are dumb; but not if that would cause overflow
+ if mem::size_of::<T>() > (!0) / 8 {
+ 1
+ } else {
+ 4
+ }
+ } else {
+ old_cap.saturating_mul(2)
+ };
+ let new_cap = max(min_cap, double_cap);
+ unsafe {
+ self.reallocate(new_cap);
+ }
+ }
+
+ /// Reserve capacity for at least `additional` more elements to be inserted.
+ ///
+ /// This method mimics the growth algorithm used by the C++ implementation
+ /// of nsTArray.
+ #[cfg(feature = "gecko-ffi")]
+ pub fn reserve(&mut self, additional: usize) {
+ let elem_size = mem::size_of::<T>();
+
+ let len = self.len();
+ let old_cap = self.capacity();
+ let min_cap = len.checked_add(additional).expect("capacity overflow");
+ if min_cap <= old_cap {
+ return;
+ }
+
+ // The growth logic can't handle zero-sized types, so we have to exit
+ // early here.
+ if elem_size == 0 {
+ unsafe {
+ self.reallocate(min_cap);
+ }
+ return;
+ }
+
+ let min_cap_bytes = assert_size(min_cap)
+ .checked_mul(assert_size(elem_size))
+ .and_then(|x| x.checked_add(assert_size(mem::size_of::<Header>())))
+ .unwrap();
+
+ // Perform some checked arithmetic to ensure all of the numbers we
+ // compute will end up in range.
+ let will_fit = min_cap_bytes.checked_mul(2).is_some();
+ if !will_fit {
+ panic!("Exceeded maximum nsTArray size");
+ }
+
+ const SLOW_GROWTH_THRESHOLD: usize = 8 * 1024 * 1024;
+
+ let bytes = if min_cap > SLOW_GROWTH_THRESHOLD {
+ // Grow by a minimum of 1.125x
+ let old_cap_bytes = old_cap * elem_size + mem::size_of::<Header>();
+ let min_growth = old_cap_bytes + (old_cap_bytes >> 3);
+ let growth = max(min_growth, min_cap_bytes as usize);
+
+ // Round up to the next megabyte.
+ const MB: usize = 1 << 20;
+ MB * ((growth + MB - 1) / MB)
+ } else {
+ // Try to allocate backing buffers in powers of two.
+ min_cap_bytes.next_power_of_two() as usize
+ };
+
+ let cap = (bytes - std::mem::size_of::<Header>()) / elem_size;
+ unsafe {
+ self.reallocate(cap);
+ }
+ }
+
+ /// Reserves the minimum capacity for `additional` more elements to be inserted.
+ ///
+ /// Panics if the new capacity overflows `usize`.
+ ///
+ /// Re-allocates only if `self.capacity() < self.len() + additional`.
+ pub fn reserve_exact(&mut self, additional: usize) {
+ let new_cap = self
+ .len()
+ .checked_add(additional)
+ .expect("capacity overflow");
+ let old_cap = self.capacity();
+ if new_cap > old_cap {
+ unsafe {
+ self.reallocate(new_cap);
+ }
+ }
+ }
+
+ /// Shrinks the capacity of the vector as much as possible.
+ ///
+ /// It will drop down as close as possible to the length but the allocator
+ /// may still inform the vector that there is space for a few more elements.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::ThinVec;
+ ///
+ /// let mut vec = ThinVec::with_capacity(10);
+ /// vec.extend([1, 2, 3]);
+ /// assert_eq!(vec.capacity(), 10);
+ /// vec.shrink_to_fit();
+ /// assert!(vec.capacity() >= 3);
+ /// ```
+ pub fn shrink_to_fit(&mut self) {
+ let old_cap = self.capacity();
+ let new_cap = self.len();
+ if new_cap < old_cap {
+ if new_cap == 0 {
+ *self = ThinVec::new();
+ } else {
+ unsafe {
+ self.reallocate(new_cap);
+ }
+ }
+ }
+ }
+
+ /// Retains only the elements specified by the predicate.
+ ///
+ /// In other words, remove all elements `e` such that `f(&e)` returns `false`.
+ /// This method operates in place and preserves the order of the retained
+ /// elements.
+ ///
+ /// # Examples
+ ///
+ // A hack to avoid linking problems with `cargo test --features=gecko-ffi`.
+ #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")]
+ #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")]
+ /// # #[macro_use] extern crate thin_vec;
+ /// # fn main() {
+ /// let mut vec = thin_vec![1, 2, 3, 4];
+ /// vec.retain(|&x| x%2 == 0);
+ /// assert_eq!(vec, [2, 4]);
+ /// # }
+ /// ```
+ pub fn retain<F>(&mut self, mut f: F)
+ where
+ F: FnMut(&T) -> bool,
+ {
+ self.retain_mut(|x| f(&*x));
+ }
+
+ /// Retains only the elements specified by the predicate, passing a mutable reference to it.
+ ///
+ /// In other words, remove all elements `e` such that `f(&mut e)` returns `false`.
+ /// This method operates in place and preserves the order of the retained
+ /// elements.
+ ///
+ /// # Examples
+ ///
+ // A hack to avoid linking problems with `cargo test --features=gecko-ffi`.
+ #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")]
+ #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")]
+ /// # #[macro_use] extern crate thin_vec;
+ /// # fn main() {
+ /// let mut vec = thin_vec![1, 2, 3, 4, 5];
+ /// vec.retain_mut(|x| {
+ /// *x += 1;
+ /// (*x)%2 == 0
+ /// });
+ /// assert_eq!(vec, [2, 4, 6]);
+ /// # }
+ /// ```
+ pub fn retain_mut<F>(&mut self, mut f: F)
+ where
+ F: FnMut(&mut T) -> bool,
+ {
+ let len = self.len();
+ let mut del = 0;
+ {
+ let v = &mut self[..];
+
+ for i in 0..len {
+ if !f(&mut v[i]) {
+ del += 1;
+ } else if del > 0 {
+ v.swap(i - del, i);
+ }
+ }
+ }
+ if del > 0 {
+ self.truncate(len - del);
+ }
+ }
+
+ /// Removes consecutive elements in the vector that resolve to the same key.
+ ///
+ /// If the vector is sorted, this removes all duplicates.
+ ///
+ /// # Examples
+ ///
+ // A hack to avoid linking problems with `cargo test --features=gecko-ffi`.
+ #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")]
+ #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")]
+ /// # #[macro_use] extern crate thin_vec;
+ /// # fn main() {
+ /// let mut vec = thin_vec![10, 20, 21, 30, 20];
+ ///
+ /// vec.dedup_by_key(|i| *i / 10);
+ ///
+ /// assert_eq!(vec, [10, 20, 30, 20]);
+ /// # }
+ /// ```
+ pub fn dedup_by_key<F, K>(&mut self, mut key: F)
+ where
+ F: FnMut(&mut T) -> K,
+ K: PartialEq<K>,
+ {
+ self.dedup_by(|a, b| key(a) == key(b))
+ }
+
+ /// Removes consecutive elements in the vector according to a predicate.
+ ///
+ /// The `same_bucket` function is passed references to two elements from the vector, and
+ /// returns `true` if the elements compare equal, or `false` if they do not. Only the first
+ /// of adjacent equal items is kept.
+ ///
+ /// If the vector is sorted, this removes all duplicates.
+ ///
+ /// # Examples
+ ///
+ // A hack to avoid linking problems with `cargo test --features=gecko-ffi`.
+ #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")]
+ #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")]
+ /// # #[macro_use] extern crate thin_vec;
+ /// # fn main() {
+ /// let mut vec = thin_vec!["foo", "bar", "Bar", "baz", "bar"];
+ ///
+ /// vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b));
+ ///
+ /// assert_eq!(vec, ["foo", "bar", "baz", "bar"]);
+ /// # }
+ /// ```
+ #[allow(clippy::swap_ptr_to_ref)]
+ pub fn dedup_by<F>(&mut self, mut same_bucket: F)
+ where
+ F: FnMut(&mut T, &mut T) -> bool,
+ {
+ // See the comments in `Vec::dedup` for a detailed explanation of this code.
+ unsafe {
+ let ln = self.len();
+ if ln <= 1 {
+ return;
+ }
+
+ // Avoid bounds checks by using raw pointers.
+ let p = self.as_mut_ptr();
+ let mut r: usize = 1;
+ let mut w: usize = 1;
+
+ while r < ln {
+ let p_r = p.add(r);
+ let p_wm1 = p.add(w - 1);
+ if !same_bucket(&mut *p_r, &mut *p_wm1) {
+ if r != w {
+ let p_w = p_wm1.add(1);
+ mem::swap(&mut *p_r, &mut *p_w);
+ }
+ w += 1;
+ }
+ r += 1;
+ }
+
+ self.truncate(w);
+ }
+ }
+
+ /// Splits the collection into two at the given index.
+ ///
+ /// Returns a newly allocated vector containing the elements in the range
+ /// `[at, len)`. After the call, the original vector will be left containing
+ /// the elements `[0, at)` with its previous capacity unchanged.
+ ///
+ /// # Panics
+ ///
+ /// Panics if `at > len`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![1, 2, 3];
+ /// let vec2 = vec.split_off(1);
+ /// assert_eq!(vec, [1]);
+ /// assert_eq!(vec2, [2, 3]);
+ /// ```
+ pub fn split_off(&mut self, at: usize) -> ThinVec<T> {
+ let old_len = self.len();
+ let new_vec_len = old_len - at;
+
+ assert!(at <= old_len, "Index out of bounds");
+
+ unsafe {
+ let mut new_vec = ThinVec::with_capacity(new_vec_len);
+
+ ptr::copy_nonoverlapping(self.data_raw().add(at), new_vec.data_raw(), new_vec_len);
+
+ new_vec.set_len(new_vec_len); // could be the singleton
+ self.set_len(at); // could be the singleton
+
+ new_vec
+ }
+ }
+
+ /// Moves all the elements of `other` into `self`, leaving `other` empty.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![1, 2, 3];
+ /// let mut vec2 = thin_vec![4, 5, 6];
+ /// vec.append(&mut vec2);
+ /// assert_eq!(vec, [1, 2, 3, 4, 5, 6]);
+ /// assert_eq!(vec2, []);
+ /// ```
+ pub fn append(&mut self, other: &mut ThinVec<T>) {
+ self.extend(other.drain(..))
+ }
+
+ /// Removes the specified range from the vector in bulk, returning all
+ /// removed elements as an iterator. If the iterator is dropped before
+ /// being fully consumed, it drops the remaining removed elements.
+ ///
+ /// The returned iterator keeps a mutable borrow on the vector to optimize
+ /// its implementation.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the starting point is greater than the end point or if
+ /// the end point is greater than the length of the vector.
+ ///
+ /// # Leaking
+ ///
+ /// If the returned iterator goes out of scope without being dropped (due to
+ /// [`mem::forget`], for example), the vector may have lost and leaked
+ /// elements arbitrarily, including elements outside the range.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ ///
+ /// let mut v = thin_vec![1, 2, 3];
+ /// let u: ThinVec<_> = v.drain(1..).collect();
+ /// assert_eq!(v, &[1]);
+ /// assert_eq!(u, &[2, 3]);
+ ///
+ /// // A full range clears the vector, like `clear()` does
+ /// v.drain(..);
+ /// assert_eq!(v, &[]);
+ /// ```
+ pub fn drain<R>(&mut self, range: R) -> Drain<'_, T>
+ where
+ R: RangeBounds<usize>,
+ {
+ // See comments in the Drain struct itself for details on this
+ let len = self.len();
+ let start = match range.start_bound() {
+ Bound::Included(&n) => n,
+ Bound::Excluded(&n) => n + 1,
+ Bound::Unbounded => 0,
+ };
+ let end = match range.end_bound() {
+ Bound::Included(&n) => n + 1,
+ Bound::Excluded(&n) => n,
+ Bound::Unbounded => len,
+ };
+ assert!(start <= end);
+ assert!(end <= len);
+
+ unsafe {
+ // Set our length to the start bound
+ self.set_len(start); // could be the singleton
+
+ let iter =
+ slice::from_raw_parts_mut(self.data_raw().add(start), end - start).iter_mut();
+
+ Drain {
+ iter,
+ vec: self,
+ end,
+ tail: len - end,
+ }
+ }
+ }
+
+ /// Creates a splicing iterator that replaces the specified range in the vector
+ /// with the given `replace_with` iterator and yields the removed items.
+ /// `replace_with` does not need to be the same length as `range`.
+ ///
+ /// `range` is removed even if the iterator is not consumed until the end.
+ ///
+ /// It is unspecified how many elements are removed from the vector
+ /// if the `Splice` value is leaked.
+ ///
+ /// The input iterator `replace_with` is only consumed when the `Splice` value is dropped.
+ ///
+ /// This is optimal if:
+ ///
+ /// * The tail (elements in the vector after `range`) is empty,
+ /// * or `replace_with` yields fewer or equal elements than `range`’s length
+ /// * or the lower bound of its `size_hint()` is exact.
+ ///
+ /// Otherwise, a temporary vector is allocated and the tail is moved twice.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the starting point is greater than the end point or if
+ /// the end point is greater than the length of the vector.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ ///
+ /// let mut v = thin_vec![1, 2, 3, 4];
+ /// let new = [7, 8, 9];
+ /// let u: ThinVec<_> = v.splice(1..3, new).collect();
+ /// assert_eq!(v, &[1, 7, 8, 9, 4]);
+ /// assert_eq!(u, &[2, 3]);
+ /// ```
+ #[inline]
+ pub fn splice<R, I>(&mut self, range: R, replace_with: I) -> Splice<'_, I::IntoIter>
+ where
+ R: RangeBounds<usize>,
+ I: IntoIterator<Item = T>,
+ {
+ Splice {
+ drain: self.drain(range),
+ replace_with: replace_with.into_iter(),
+ }
+ }
+
+ /// Resize the buffer and update its capacity, without changing the length.
+ /// Unsafe because it can cause length to be greater than capacity.
+ unsafe fn reallocate(&mut self, new_cap: usize) {
+ debug_assert!(new_cap > 0);
+ if self.has_allocation() {
+ let old_cap = self.capacity();
+ let ptr = realloc(
+ self.ptr() as *mut u8,
+ layout::<T>(old_cap),
+ alloc_size::<T>(new_cap),
+ ) as *mut Header;
+
+ if ptr.is_null() {
+ handle_alloc_error(layout::<T>(new_cap))
+ }
+ (*ptr).set_cap(new_cap);
+ self.ptr = NonNull::new_unchecked(ptr);
+ } else {
+ let new_header = header_with_capacity::<T>(new_cap);
+
+ // If we get here and have a non-zero len, then we must be handling
+ // a gecko auto array, and we have items in a stack buffer. We shouldn't
+ // free it, but we should memcopy the contents out of it and mark it as empty.
+ //
+ // T is assumed to be trivially relocatable, as this is ~required
+ // for Rust compatibility anyway. Furthermore, we assume C++ won't try
+ // to unconditionally destroy the contents of the stack allocated buffer
+ // (i.e. it's obfuscated behind a union).
+ //
+ // In effect, we are partially reimplementing the auto array move constructor
+ // by leaving behind a valid empty instance.
+ let len = self.len();
+ if cfg!(feature = "gecko-ffi") && len > 0 {
+ new_header
+ .as_ptr()
+ .add(1)
+ .cast::<T>()
+ .copy_from_nonoverlapping(self.data_raw(), len);
+ self.set_len_non_singleton(0);
+ }
+
+ self.ptr = new_header;
+ }
+ }
+
+ #[cfg(feature = "gecko-ffi")]
+ #[inline]
+ #[allow(unused_unsafe)]
+ fn is_singleton(&self) -> bool {
+ // NOTE: the tests will complain that this "unsafe" isn't needed, but it *IS*!
+ // In production this refers to an *extern static* which *is* unsafe to reference.
+ // In tests this refers to a local static because we don't have Firefox's codebase
+ // providing the symbol!
+ unsafe { self.ptr.as_ptr() as *const Header == &EMPTY_HEADER }
+ }
+
+ #[cfg(not(feature = "gecko-ffi"))]
+ #[inline]
+ fn is_singleton(&self) -> bool {
+ self.ptr.as_ptr() as *const Header == &EMPTY_HEADER
+ }
+
+ #[cfg(feature = "gecko-ffi")]
+ #[inline]
+ fn has_allocation(&self) -> bool {
+ unsafe { !self.is_singleton() && !self.ptr.as_ref().uses_stack_allocated_buffer() }
+ }
+
+ #[cfg(not(feature = "gecko-ffi"))]
+ #[inline]
+ fn has_allocation(&self) -> bool {
+ !self.is_singleton()
+ }
+}
+
+impl<T: Clone> ThinVec<T> {
+ /// Resizes the `Vec` in-place so that `len()` is equal to `new_len`.
+ ///
+ /// If `new_len` is greater than `len()`, the `Vec` is extended by the
+ /// difference, with each additional slot filled with `value`.
+ /// If `new_len` is less than `len()`, the `Vec` is simply truncated.
+ ///
+ /// # Examples
+ ///
+ // A hack to avoid linking problems with `cargo test --features=gecko-ffi`.
+ #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")]
+ #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")]
+ /// # #[macro_use] extern crate thin_vec;
+ /// # fn main() {
+ /// let mut vec = thin_vec!["hello"];
+ /// vec.resize(3, "world");
+ /// assert_eq!(vec, ["hello", "world", "world"]);
+ ///
+ /// let mut vec = thin_vec![1, 2, 3, 4];
+ /// vec.resize(2, 0);
+ /// assert_eq!(vec, [1, 2]);
+ /// # }
+ /// ```
+ pub fn resize(&mut self, new_len: usize, value: T) {
+ let old_len = self.len();
+
+ if new_len > old_len {
+ let additional = new_len - old_len;
+ self.reserve(additional);
+ for _ in 1..additional {
+ self.push(value.clone());
+ }
+ // We can write the last element directly without cloning needlessly
+ if additional > 0 {
+ self.push(value);
+ }
+ } else if new_len < old_len {
+ self.truncate(new_len);
+ }
+ }
+
+ /// Clones and appends all elements in a slice to the `ThinVec`.
+ ///
+ /// Iterates over the slice `other`, clones each element, and then appends
+ /// it to this `ThinVec`. The `other` slice is traversed in-order.
+ ///
+ /// Note that this function is same as [`extend`] except that it is
+ /// specialized to work with slices instead. If and when Rust gets
+ /// specialization this function will likely be deprecated (but still
+ /// available).
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec![1];
+ /// vec.extend_from_slice(&[2, 3, 4]);
+ /// assert_eq!(vec, [1, 2, 3, 4]);
+ /// ```
+ ///
+ /// [`extend`]: ThinVec::extend
+ pub fn extend_from_slice(&mut self, other: &[T]) {
+ self.extend(other.iter().cloned())
+ }
+}
+
+impl<T: PartialEq> ThinVec<T> {
+ /// Removes consecutive repeated elements in the vector.
+ ///
+ /// If the vector is sorted, this removes all duplicates.
+ ///
+ /// # Examples
+ ///
+ // A hack to avoid linking problems with `cargo test --features=gecko-ffi`.
+ #[cfg_attr(not(feature = "gecko-ffi"), doc = "```")]
+ #[cfg_attr(feature = "gecko-ffi", doc = "```ignore")]
+ /// # #[macro_use] extern crate thin_vec;
+ /// # fn main() {
+ /// let mut vec = thin_vec![1, 2, 2, 3, 2];
+ ///
+ /// vec.dedup();
+ ///
+ /// assert_eq!(vec, [1, 2, 3, 2]);
+ /// # }
+ /// ```
+ pub fn dedup(&mut self) {
+ self.dedup_by(|a, b| a == b)
+ }
+}
+
+impl<T> Drop for ThinVec<T> {
+ #[inline]
+ fn drop(&mut self) {
+ #[cold]
+ #[inline(never)]
+ fn drop_non_singleton<T>(this: &mut ThinVec<T>) {
+ unsafe {
+ ptr::drop_in_place(&mut this[..]);
+
+ #[cfg(feature = "gecko-ffi")]
+ if this.ptr.as_ref().uses_stack_allocated_buffer() {
+ return;
+ }
+
+ dealloc(this.ptr() as *mut u8, layout::<T>(this.capacity()))
+ }
+ }
+
+ if !self.is_singleton() {
+ drop_non_singleton(self);
+ }
+ }
+}
+
+impl<T> Deref for ThinVec<T> {
+ type Target = [T];
+
+ fn deref(&self) -> &[T] {
+ self.as_slice()
+ }
+}
+
+impl<T> DerefMut for ThinVec<T> {
+ fn deref_mut(&mut self) -> &mut [T] {
+ self.as_mut_slice()
+ }
+}
+
+impl<T> Borrow<[T]> for ThinVec<T> {
+ fn borrow(&self) -> &[T] {
+ self.as_slice()
+ }
+}
+
+impl<T> BorrowMut<[T]> for ThinVec<T> {
+ fn borrow_mut(&mut self) -> &mut [T] {
+ self.as_mut_slice()
+ }
+}
+
+impl<T> AsRef<[T]> for ThinVec<T> {
+ fn as_ref(&self) -> &[T] {
+ self.as_slice()
+ }
+}
+
+impl<T> Extend<T> for ThinVec<T> {
+ #[inline]
+ fn extend<I>(&mut self, iter: I)
+ where
+ I: IntoIterator<Item = T>,
+ {
+ let iter = iter.into_iter();
+ let hint = iter.size_hint().0;
+ if hint > 0 {
+ self.reserve(hint);
+ }
+ for x in iter {
+ self.push(x);
+ }
+ }
+}
+
+impl<T: fmt::Debug> fmt::Debug for ThinVec<T> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Debug::fmt(&**self, f)
+ }
+}
+
+impl<T> Hash for ThinVec<T>
+where
+ T: Hash,
+{
+ fn hash<H>(&self, state: &mut H)
+ where
+ H: Hasher,
+ {
+ self[..].hash(state);
+ }
+}
+
+impl<T> PartialOrd for ThinVec<T>
+where
+ T: PartialOrd,
+{
+ #[inline]
+ fn partial_cmp(&self, other: &ThinVec<T>) -> Option<Ordering> {
+ self[..].partial_cmp(&other[..])
+ }
+}
+
+impl<T> Ord for ThinVec<T>
+where
+ T: Ord,
+{
+ #[inline]
+ fn cmp(&self, other: &ThinVec<T>) -> Ordering {
+ self[..].cmp(&other[..])
+ }
+}
+
+impl<A, B> PartialEq<ThinVec<B>> for ThinVec<A>
+where
+ A: PartialEq<B>,
+{
+ #[inline]
+ fn eq(&self, other: &ThinVec<B>) -> bool {
+ self[..] == other[..]
+ }
+}
+
+impl<A, B> PartialEq<Vec<B>> for ThinVec<A>
+where
+ A: PartialEq<B>,
+{
+ #[inline]
+ fn eq(&self, other: &Vec<B>) -> bool {
+ self[..] == other[..]
+ }
+}
+
+impl<A, B> PartialEq<[B]> for ThinVec<A>
+where
+ A: PartialEq<B>,
+{
+ #[inline]
+ fn eq(&self, other: &[B]) -> bool {
+ self[..] == other[..]
+ }
+}
+
+impl<'a, A, B> PartialEq<&'a [B]> for ThinVec<A>
+where
+ A: PartialEq<B>,
+{
+ #[inline]
+ fn eq(&self, other: &&'a [B]) -> bool {
+ self[..] == other[..]
+ }
+}
+
+// Serde impls based on
+// https://github.com/bluss/arrayvec/blob/67ec907a98c0f40c4b76066fed3c1af59d35cf6a/src/arrayvec.rs#L1222-L1267
+#[cfg(feature = "serde")]
+impl<T: serde::Serialize> serde::Serialize for ThinVec<T> {
+ fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+ where
+ S: serde::Serializer,
+ {
+ serializer.collect_seq(self.as_slice())
+ }
+}
+
+#[cfg(feature = "serde")]
+impl<'de, T: serde::Deserialize<'de>> serde::Deserialize<'de> for ThinVec<T> {
+ fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+ where
+ D: serde::Deserializer<'de>,
+ {
+ use serde::de::{SeqAccess, Visitor};
+ use serde::Deserialize;
+
+ struct ThinVecVisitor<T>(PhantomData<T>);
+
+ impl<'de, T: Deserialize<'de>> Visitor<'de> for ThinVecVisitor<T> {
+ type Value = ThinVec<T>;
+
+ fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+ write!(formatter, "a sequence")
+ }
+
+ fn visit_seq<SA>(self, mut seq: SA) -> Result<Self::Value, SA::Error>
+ where
+ SA: SeqAccess<'de>,
+ {
+ // Same policy as
+ // https://github.com/serde-rs/serde/blob/ce0844b9ecc32377b5e4545d759d385a8c46bc6a/serde/src/private/size_hint.rs#L13
+ let initial_capacity = seq.size_hint().unwrap_or_default().min(4096);
+ let mut values = ThinVec::<T>::with_capacity(initial_capacity);
+
+ while let Some(value) = seq.next_element()? {
+ values.push(value);
+ }
+
+ Ok(values)
+ }
+ }
+
+ deserializer.deserialize_seq(ThinVecVisitor::<T>(PhantomData))
+ }
+}
+
+macro_rules! array_impls {
+ ($($N:expr)*) => {$(
+ impl<A, B> PartialEq<[B; $N]> for ThinVec<A> where A: PartialEq<B> {
+ #[inline]
+ fn eq(&self, other: &[B; $N]) -> bool { self[..] == other[..] }
+ }
+
+ impl<'a, A, B> PartialEq<&'a [B; $N]> for ThinVec<A> where A: PartialEq<B> {
+ #[inline]
+ fn eq(&self, other: &&'a [B; $N]) -> bool { self[..] == other[..] }
+ }
+ )*}
+}
+
+array_impls! {
+ 0 1 2 3 4 5 6 7 8 9
+ 10 11 12 13 14 15 16 17 18 19
+ 20 21 22 23 24 25 26 27 28 29
+ 30 31 32
+}
+
+impl<T> Eq for ThinVec<T> where T: Eq {}
+
+impl<T> IntoIterator for ThinVec<T> {
+ type Item = T;
+ type IntoIter = IntoIter<T>;
+
+ fn into_iter(self) -> IntoIter<T> {
+ IntoIter {
+ vec: self,
+ start: 0,
+ }
+ }
+}
+
+impl<'a, T> IntoIterator for &'a ThinVec<T> {
+ type Item = &'a T;
+ type IntoIter = slice::Iter<'a, T>;
+
+ fn into_iter(self) -> slice::Iter<'a, T> {
+ self.iter()
+ }
+}
+
+impl<'a, T> IntoIterator for &'a mut ThinVec<T> {
+ type Item = &'a mut T;
+ type IntoIter = slice::IterMut<'a, T>;
+
+ fn into_iter(self) -> slice::IterMut<'a, T> {
+ self.iter_mut()
+ }
+}
+
+impl<T> Clone for ThinVec<T>
+where
+ T: Clone,
+{
+ #[inline]
+ fn clone(&self) -> ThinVec<T> {
+ #[cold]
+ #[inline(never)]
+ fn clone_non_singleton<T: Clone>(this: &ThinVec<T>) -> ThinVec<T> {
+ let len = this.len();
+ let mut new_vec = ThinVec::<T>::with_capacity(len);
+ let mut data_raw = new_vec.data_raw();
+ for x in this.iter() {
+ unsafe {
+ ptr::write(data_raw, x.clone());
+ data_raw = data_raw.add(1);
+ }
+ }
+ unsafe {
+ // `this` is not the singleton, but `new_vec` will be if
+ // `this` is empty.
+ new_vec.set_len(len); // could be the singleton
+ }
+ new_vec
+ }
+
+ if self.is_singleton() {
+ ThinVec::new()
+ } else {
+ clone_non_singleton(self)
+ }
+ }
+}
+
+impl<T> Default for ThinVec<T> {
+ fn default() -> ThinVec<T> {
+ ThinVec::new()
+ }
+}
+
+impl<T> FromIterator<T> for ThinVec<T> {
+ #[inline]
+ fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> ThinVec<T> {
+ let mut vec = ThinVec::new();
+ vec.extend(iter.into_iter());
+ vec
+ }
+}
+
+impl<T: Clone> From<&[T]> for ThinVec<T> {
+ /// Allocate a `ThinVec<T>` and fill it by cloning `s`'s items.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ ///
+ /// assert_eq!(ThinVec::from(&[1, 2, 3][..]), thin_vec![1, 2, 3]);
+ /// ```
+ fn from(s: &[T]) -> ThinVec<T> {
+ s.iter().cloned().collect()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T: Clone> From<&mut [T]> for ThinVec<T> {
+ /// Allocate a `ThinVec<T>` and fill it by cloning `s`'s items.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ ///
+ /// assert_eq!(ThinVec::from(&mut [1, 2, 3][..]), thin_vec![1, 2, 3]);
+ /// ```
+ fn from(s: &mut [T]) -> ThinVec<T> {
+ s.iter().cloned().collect()
+ }
+}
+
+impl<T, const N: usize> From<[T; N]> for ThinVec<T> {
+ /// Allocate a `ThinVec<T>` and move `s`'s items into it.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ ///
+ /// assert_eq!(ThinVec::from([1, 2, 3]), thin_vec![1, 2, 3]);
+ /// ```
+ fn from(s: [T; N]) -> ThinVec<T> {
+ std::iter::IntoIterator::into_iter(s).collect()
+ }
+}
+
+impl<T> From<Box<[T]>> for ThinVec<T> {
+ /// Convert a boxed slice into a vector by transferring ownership of
+ /// the existing heap allocation.
+ ///
+ /// **NOTE:** unlike `std`, this must reallocate to change the layout!
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ ///
+ /// let b: Box<[i32]> = thin_vec![1, 2, 3].into_iter().collect();
+ /// assert_eq!(ThinVec::from(b), thin_vec![1, 2, 3]);
+ /// ```
+ fn from(s: Box<[T]>) -> Self {
+ // Can just lean on the fact that `Box<[T]>` -> `Vec<T>` is Free.
+ Vec::from(s).into_iter().collect()
+ }
+}
+
+impl<T> From<Vec<T>> for ThinVec<T> {
+ /// Convert a `std::Vec` into a `ThinVec`.
+ ///
+ /// **NOTE:** this must reallocate to change the layout!
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ ///
+ /// let b: Vec<i32> = vec![1, 2, 3];
+ /// assert_eq!(ThinVec::from(b), thin_vec![1, 2, 3]);
+ /// ```
+ fn from(s: Vec<T>) -> Self {
+ s.into_iter().collect()
+ }
+}
+
+impl<T> From<ThinVec<T>> for Vec<T> {
+ /// Convert a `ThinVec` into a `std::Vec`.
+ ///
+ /// **NOTE:** this must reallocate to change the layout!
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ ///
+ /// let b: ThinVec<i32> = thin_vec![1, 2, 3];
+ /// assert_eq!(Vec::from(b), vec![1, 2, 3]);
+ /// ```
+ fn from(s: ThinVec<T>) -> Self {
+ s.into_iter().collect()
+ }
+}
+
+impl<T> From<ThinVec<T>> for Box<[T]> {
+ /// Convert a vector into a boxed slice.
+ ///
+ /// If `v` has excess capacity, its items will be moved into a
+ /// newly-allocated buffer with exactly the right capacity.
+ ///
+ /// **NOTE:** unlike `std`, this must reallocate to change the layout!
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ /// assert_eq!(Box::from(thin_vec![1, 2, 3]), thin_vec![1, 2, 3].into_iter().collect());
+ /// ```
+ fn from(v: ThinVec<T>) -> Self {
+ v.into_iter().collect()
+ }
+}
+
+impl From<&str> for ThinVec<u8> {
+ /// Allocate a `ThinVec<u8>` and fill it with a UTF-8 string.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ ///
+ /// assert_eq!(ThinVec::from("123"), thin_vec![b'1', b'2', b'3']);
+ /// ```
+ fn from(s: &str) -> ThinVec<u8> {
+ From::from(s.as_bytes())
+ }
+}
+
+impl<T, const N: usize> TryFrom<ThinVec<T>> for [T; N] {
+ type Error = ThinVec<T>;
+
+ /// Gets the entire contents of the `ThinVec<T>` as an array,
+ /// if its size exactly matches that of the requested array.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ /// use std::convert::TryInto;
+ ///
+ /// assert_eq!(thin_vec![1, 2, 3].try_into(), Ok([1, 2, 3]));
+ /// assert_eq!(<ThinVec<i32>>::new().try_into(), Ok([]));
+ /// ```
+ ///
+ /// If the length doesn't match, the input comes back in `Err`:
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ /// use std::convert::TryInto;
+ ///
+ /// let r: Result<[i32; 4], _> = (0..10).collect::<ThinVec<_>>().try_into();
+ /// assert_eq!(r, Err(thin_vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9]));
+ /// ```
+ ///
+ /// If you're fine with just getting a prefix of the `ThinVec<T>`,
+ /// you can call [`.truncate(N)`](ThinVec::truncate) first.
+ /// ```
+ /// use thin_vec::{ThinVec, thin_vec};
+ /// use std::convert::TryInto;
+ ///
+ /// let mut v = ThinVec::from("hello world");
+ /// v.sort();
+ /// v.truncate(2);
+ /// let [a, b]: [_; 2] = v.try_into().unwrap();
+ /// assert_eq!(a, b' ');
+ /// assert_eq!(b, b'd');
+ /// ```
+ fn try_from(mut vec: ThinVec<T>) -> Result<[T; N], ThinVec<T>> {
+ if vec.len() != N {
+ return Err(vec);
+ }
+
+ // SAFETY: `.set_len(0)` is always sound.
+ unsafe { vec.set_len(0) };
+
+ // SAFETY: A `ThinVec`'s pointer is always aligned properly, and
+ // the alignment the array needs is the same as the items.
+ // We checked earlier that we have sufficient items.
+ // The items will not double-drop as the `set_len`
+ // tells the `ThinVec` not to also drop them.
+ let array = unsafe { ptr::read(vec.data_raw() as *const [T; N]) };
+ Ok(array)
+ }
+}
+
+/// An iterator that moves out of a vector.
+///
+/// This `struct` is created by the [`ThinVec::into_iter`][]
+/// (provided by the [`IntoIterator`] trait).
+///
+/// # Example
+///
+/// ```
+/// use thin_vec::thin_vec;
+///
+/// let v = thin_vec![0, 1, 2];
+/// let iter: thin_vec::IntoIter<_> = v.into_iter();
+/// ```
+pub struct IntoIter<T> {
+ vec: ThinVec<T>,
+ start: usize,
+}
+
+impl<T> IntoIter<T> {
+ /// Returns the remaining items of this iterator as a slice.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let vec = thin_vec!['a', 'b', 'c'];
+ /// let mut into_iter = vec.into_iter();
+ /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+ /// let _ = into_iter.next().unwrap();
+ /// assert_eq!(into_iter.as_slice(), &['b', 'c']);
+ /// ```
+ pub fn as_slice(&self) -> &[T] {
+ unsafe { slice::from_raw_parts(self.vec.data_raw().add(self.start), self.len()) }
+ }
+
+ /// Returns the remaining items of this iterator as a mutable slice.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let vec = thin_vec!['a', 'b', 'c'];
+ /// let mut into_iter = vec.into_iter();
+ /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+ /// into_iter.as_mut_slice()[2] = 'z';
+ /// assert_eq!(into_iter.next().unwrap(), 'a');
+ /// assert_eq!(into_iter.next().unwrap(), 'b');
+ /// assert_eq!(into_iter.next().unwrap(), 'z');
+ /// ```
+ pub fn as_mut_slice(&mut self) -> &mut [T] {
+ unsafe { &mut *self.as_raw_mut_slice() }
+ }
+
+ fn as_raw_mut_slice(&mut self) -> *mut [T] {
+ unsafe { ptr::slice_from_raw_parts_mut(self.vec.data_raw().add(self.start), self.len()) }
+ }
+}
+
+impl<T> Iterator for IntoIter<T> {
+ type Item = T;
+ fn next(&mut self) -> Option<T> {
+ if self.start == self.vec.len() {
+ None
+ } else {
+ unsafe {
+ let old_start = self.start;
+ self.start += 1;
+ Some(ptr::read(self.vec.data_raw().add(old_start)))
+ }
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ let len = self.vec.len() - self.start;
+ (len, Some(len))
+ }
+}
+
+impl<T> DoubleEndedIterator for IntoIter<T> {
+ fn next_back(&mut self) -> Option<T> {
+ if self.start == self.vec.len() {
+ None
+ } else {
+ self.vec.pop()
+ }
+ }
+}
+
+impl<T> ExactSizeIterator for IntoIter<T> {}
+
+impl<T> std::iter::FusedIterator for IntoIter<T> {}
+
+// SAFETY: the length calculation is trivial, we're an array! And if it's wrong we're So Screwed.
+#[cfg(feature = "unstable")]
+unsafe impl<T> std::iter::TrustedLen for IntoIter<T> {}
+
+impl<T> Drop for IntoIter<T> {
+ #[inline]
+ fn drop(&mut self) {
+ #[cold]
+ #[inline(never)]
+ fn drop_non_singleton<T>(this: &mut IntoIter<T>) {
+ unsafe {
+ let mut vec = mem::replace(&mut this.vec, ThinVec::new());
+ ptr::drop_in_place(&mut vec[this.start..]);
+ vec.set_len_non_singleton(0)
+ }
+ }
+
+ if !self.vec.is_singleton() {
+ drop_non_singleton(self);
+ }
+ }
+}
+
+impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_tuple("IntoIter").field(&self.as_slice()).finish()
+ }
+}
+
+impl<T> AsRef<[T]> for IntoIter<T> {
+ fn as_ref(&self) -> &[T] {
+ self.as_slice()
+ }
+}
+
+impl<T: Clone> Clone for IntoIter<T> {
+ #[allow(clippy::into_iter_on_ref)]
+ fn clone(&self) -> Self {
+ // Just create a new `ThinVec` from the remaining elements and IntoIter it
+ self.as_slice()
+ .into_iter()
+ .cloned()
+ .collect::<ThinVec<_>>()
+ .into_iter()
+ }
+}
+
+/// A draining iterator for `ThinVec<T>`.
+///
+/// This `struct` is created by [`ThinVec::drain`].
+/// See its documentation for more.
+///
+/// # Example
+///
+/// ```
+/// use thin_vec::thin_vec;
+///
+/// let mut v = thin_vec![0, 1, 2];
+/// let iter: thin_vec::Drain<_> = v.drain(..);
+/// ```
+pub struct Drain<'a, T> {
+ // Ok so ThinVec::drain takes a range of the ThinVec and yields the contents by-value,
+ // then backshifts the array. During iteration the array is in an unsound state
+ // (big deinitialized hole in it), and this is very dangerous.
+ //
+ // Our first line of defense is the borrow checker: we have a mutable borrow, so nothing
+ // can access the ThinVec while we exist. As long as we make sure the ThinVec is in a valid
+ // state again before we release the borrow, everything should be A-OK! We do this cleanup
+ // in our Drop impl.
+ //
+ // Unfortunately, that's unsound, because mem::forget exists and The Leakpocalypse Is Real.
+ // So we can't actually guarantee our destructor runs before our borrow expires. Thankfully
+ // this isn't fatal: we can just set the ThinVec's len to 0 at the start, so if anyone
+ // leaks the Drain, we just leak everything the ThinVec contained out of spite! If they
+ // *don't* leak us then we can properly repair the len in our Drop impl. This is known
+ // as "leak amplification", and is the same approach std uses.
+ //
+ // But we can do slightly better than setting the len to 0! The drain breaks us up into
+ // these parts:
+ //
+ // ```text
+ //
+ // [A, B, C, D, E, F, G, H, _, _]
+ // ____ __________ ____ ____
+ // | | | |
+ // prefix drain tail spare-cap
+ // ```
+ //
+ // As the drain iterator is consumed from both ends (DoubleEnded!), we'll start to look
+ // like this:
+ //
+ // ```text
+ // [A, B, _, _, E, _, G, H, _, _]
+ // ____ __________ ____ ____
+ // | | | |
+ // prefix drain tail spare-cap
+ // ```
+ //
+ // Note that the prefix is always valid and untouched, as such we can set the len
+ // to the prefix when doing leak-amplification. As a bonus, we can use this value
+ // to remember where the drain range starts. At the end we'll look like this
+ // (we exhaust ourselves in our Drop impl):
+ //
+ // ```text
+ // [A, B, _, _, _, _, G, H, _, _]
+ // _____ __________ _____ ____
+ // | | | |
+ // len drain tail spare-cap
+ // ```
+ //
+ // And need to become this:
+ //
+ // ```text
+ // [A, B, G, H, _, _, _, _, _, _]
+ // ___________ ________________
+ // | |
+ // len spare-cap
+ // ```
+ //
+ // All this requires is moving the tail back to the prefix (stored in `len`)
+ // and setting `len` to `len + tail_len` to undo the leak amplification.
+ /// An iterator over the elements we're removing.
+ ///
+ /// As we go we'll be `read`ing out of the mutable refs yielded by this.
+ /// It's ok to use IterMut here because it promises to only take mutable
+ /// refs to the parts we haven't yielded yet.
+ ///
+ /// A downside of this (and the *mut below) is that it makes this type invariant, when
+ /// technically it could be covariant?
+ iter: IterMut<'a, T>,
+ /// The actual ThinVec, which we need to hold onto to undo the leak amplification
+ /// and backshift the tail into place. This should only be accessed when we're
+ /// completely done with the IterMut in the `drop` impl of this type (or miri will get mad).
+ ///
+ /// Since we set the `len` of this to be before `IterMut`, we can use that `len`
+ /// to retrieve the index of the start of the drain range later.
+ vec: *mut ThinVec<T>,
+ /// The one-past-the-end index of the drain range, or equivalently the start of the tail.
+ end: usize,
+ /// The length of the tail.
+ tail: usize,
+}
+
+impl<'a, T> Iterator for Drain<'a, T> {
+ type Item = T;
+ fn next(&mut self) -> Option<T> {
+ self.iter.next().map(|x| unsafe { ptr::read(x) })
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+}
+
+impl<'a, T> DoubleEndedIterator for Drain<'a, T> {
+ fn next_back(&mut self) -> Option<T> {
+ self.iter.next_back().map(|x| unsafe { ptr::read(x) })
+ }
+}
+
+impl<'a, T> ExactSizeIterator for Drain<'a, T> {}
+
+// SAFETY: we need to keep track of this perfectly Or Else anyway!
+#[cfg(feature = "unstable")]
+unsafe impl<T> std::iter::TrustedLen for Drain<'_, T> {}
+
+impl<T> std::iter::FusedIterator for Drain<'_, T> {}
+
+impl<'a, T> Drop for Drain<'a, T> {
+ fn drop(&mut self) {
+ // Consume the rest of the iterator.
+ for _ in self.by_ref() {}
+
+ // Move the tail over the drained items, and update the length.
+ unsafe {
+ let vec = &mut *self.vec;
+
+ // Don't mutate the empty singleton!
+ if !vec.is_singleton() {
+ let old_len = vec.len();
+ let start = vec.data_raw().add(old_len);
+ let end = vec.data_raw().add(self.end);
+ ptr::copy(end, start, self.tail);
+ vec.set_len_non_singleton(old_len + self.tail);
+ }
+ }
+ }
+}
+
+impl<T: fmt::Debug> fmt::Debug for Drain<'_, T> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_tuple("Drain").field(&self.iter.as_slice()).finish()
+ }
+}
+
+impl<'a, T> Drain<'a, T> {
+ /// Returns the remaining items of this iterator as a slice.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use thin_vec::thin_vec;
+ ///
+ /// let mut vec = thin_vec!['a', 'b', 'c'];
+ /// let mut drain = vec.drain(..);
+ /// assert_eq!(drain.as_slice(), &['a', 'b', 'c']);
+ /// let _ = drain.next().unwrap();
+ /// assert_eq!(drain.as_slice(), &['b', 'c']);
+ /// ```
+ #[must_use]
+ pub fn as_slice(&self) -> &[T] {
+ // SAFETY: this is A-OK because the elements that the underlying
+ // iterator still points at are still logically initialized and contiguous.
+ self.iter.as_slice()
+ }
+}
+
+impl<'a, T> AsRef<[T]> for Drain<'a, T> {
+ fn as_ref(&self) -> &[T] {
+ self.as_slice()
+ }
+}
+
+/// A splicing iterator for `ThinVec`.
+///
+/// This struct is created by [`ThinVec::splice`][].
+/// See its documentation for more.
+///
+/// # Example
+///
+/// ```
+/// use thin_vec::thin_vec;
+///
+/// let mut v = thin_vec![0, 1, 2];
+/// let new = [7, 8];
+/// let iter: thin_vec::Splice<_> = v.splice(1.., new);
+/// ```
+#[derive(Debug)]
+pub struct Splice<'a, I: Iterator + 'a> {
+ drain: Drain<'a, I::Item>,
+ replace_with: I,
+}
+
+impl<I: Iterator> Iterator for Splice<'_, I> {
+ type Item = I::Item;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.drain.next()
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.drain.size_hint()
+ }
+}
+
+impl<I: Iterator> DoubleEndedIterator for Splice<'_, I> {
+ fn next_back(&mut self) -> Option<Self::Item> {
+ self.drain.next_back()
+ }
+}
+
+impl<I: Iterator> ExactSizeIterator for Splice<'_, I> {}
+
+impl<I: Iterator> Drop for Splice<'_, I> {
+ fn drop(&mut self) {
+ // Ensure we've fully drained out the range
+ self.drain.by_ref().for_each(drop);
+
+ unsafe {
+ // If there's no tail elements, then the inner ThinVec is already
+ // correct and we can just extend it like normal.
+ if self.drain.tail == 0 {
+ (*self.drain.vec).extend(self.replace_with.by_ref());
+ return;
+ }
+
+ // First fill the range left by drain().
+ if !self.drain.fill(&mut self.replace_with) {
+ return;
+ }
+
+ // There may be more elements. Use the lower bound as an estimate.
+ let (lower_bound, _upper_bound) = self.replace_with.size_hint();
+ if lower_bound > 0 {
+ self.drain.move_tail(lower_bound);
+ if !self.drain.fill(&mut self.replace_with) {
+ return;
+ }
+ }
+
+ // Collect any remaining elements.
+ // This is a zero-length vector which does not allocate if `lower_bound` was exact.
+ let mut collected = self
+ .replace_with
+ .by_ref()
+ .collect::<Vec<I::Item>>()
+ .into_iter();
+ // Now we have an exact count.
+ if collected.len() > 0 {
+ self.drain.move_tail(collected.len());
+ let filled = self.drain.fill(&mut collected);
+ debug_assert!(filled);
+ debug_assert_eq!(collected.len(), 0);
+ }
+ }
+ // Let `Drain::drop` move the tail back if necessary and restore `vec.len`.
+ }
+}
+
+/// Private helper methods for `Splice::drop`
+impl<T> Drain<'_, T> {
+ /// The range from `self.vec.len` to `self.tail_start` contains elements
+ /// that have been moved out.
+ /// Fill that range as much as possible with new elements from the `replace_with` iterator.
+ /// Returns `true` if we filled the entire range. (`replace_with.next()` didn’t return `None`.)
+ unsafe fn fill<I: Iterator<Item = T>>(&mut self, replace_with: &mut I) -> bool {
+ let vec = unsafe { &mut *self.vec };
+ let range_start = vec.len();
+ let range_end = self.end;
+ let range_slice = unsafe {
+ slice::from_raw_parts_mut(vec.data_raw().add(range_start), range_end - range_start)
+ };
+
+ for place in range_slice {
+ if let Some(new_item) = replace_with.next() {
+ unsafe { ptr::write(place, new_item) };
+ vec.set_len(vec.len() + 1);
+ } else {
+ return false;
+ }
+ }
+ true
+ }
+
+ /// Makes room for inserting more elements before the tail.
+ unsafe fn move_tail(&mut self, additional: usize) {
+ let vec = unsafe { &mut *self.vec };
+ let len = self.end + self.tail;
+ vec.reserve(len.checked_add(additional).expect("capacity overflow"));
+
+ let new_tail_start = self.end + additional;
+ unsafe {
+ let src = vec.data_raw().add(self.end);
+ let dst = vec.data_raw().add(new_tail_start);
+ ptr::copy(src, dst, self.tail);
+ }
+ self.end = new_tail_start;
+ }
+}
+
+/// Write is implemented for `ThinVec<u8>` by appending to the vector.
+/// The vector will grow as needed.
+/// This implementation is identical to the one for `Vec<u8>`.
+impl io::Write for ThinVec<u8> {
+ #[inline]
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ self.extend_from_slice(buf);
+ Ok(buf.len())
+ }
+
+ #[inline]
+ fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+ self.extend_from_slice(buf);
+ Ok(())
+ }
+
+ #[inline]
+ fn flush(&mut self) -> io::Result<()> {
+ Ok(())
+ }
+}
+
+// TODO: a million Index impls
+
+#[cfg(test)]
+mod tests {
+ use super::{ThinVec, MAX_CAP};
+
+ #[test]
+ fn test_size_of() {
+ use std::mem::size_of;
+ assert_eq!(size_of::<ThinVec<u8>>(), size_of::<&u8>());
+
+ assert_eq!(size_of::<Option<ThinVec<u8>>>(), size_of::<&u8>());
+ }
+
+ #[test]
+ fn test_drop_empty() {
+ ThinVec::<u8>::new();
+ }
+
+ #[test]
+ fn test_data_ptr_alignment() {
+ let v = ThinVec::<u16>::new();
+ assert!(v.data_raw() as usize % 2 == 0);
+
+ let v = ThinVec::<u32>::new();
+ assert!(v.data_raw() as usize % 4 == 0);
+
+ let v = ThinVec::<u64>::new();
+ assert!(v.data_raw() as usize % 8 == 0);
+ }
+
+ #[test]
+ #[cfg_attr(feature = "gecko-ffi", should_panic)]
+ fn test_overaligned_type_is_rejected_for_gecko_ffi_mode() {
+ #[repr(align(16))]
+ struct Align16(u8);
+
+ let v = ThinVec::<Align16>::new();
+ assert!(v.data_raw() as usize % 16 == 0);
+ }
+
+ #[test]
+ fn test_partial_eq() {
+ assert_eq!(thin_vec![0], thin_vec![0]);
+ assert_ne!(thin_vec![0], thin_vec![1]);
+ assert_eq!(thin_vec![1, 2, 3], vec![1, 2, 3]);
+ }
+
+ #[test]
+ fn test_alloc() {
+ let mut v = ThinVec::new();
+ assert!(!v.has_allocation());
+ v.push(1);
+ assert!(v.has_allocation());
+ v.pop();
+ assert!(v.has_allocation());
+ v.shrink_to_fit();
+ assert!(!v.has_allocation());
+ v.reserve(64);
+ assert!(v.has_allocation());
+ v = ThinVec::with_capacity(64);
+ assert!(v.has_allocation());
+ v = ThinVec::with_capacity(0);
+ assert!(!v.has_allocation());
+ }
+
+ #[test]
+ fn test_drain_items() {
+ let mut vec = thin_vec![1, 2, 3];
+ let mut vec2 = thin_vec![];
+ for i in vec.drain(..) {
+ vec2.push(i);
+ }
+ assert_eq!(vec, []);
+ assert_eq!(vec2, [1, 2, 3]);
+ }
+
+ #[test]
+ fn test_drain_items_reverse() {
+ let mut vec = thin_vec![1, 2, 3];
+ let mut vec2 = thin_vec![];
+ for i in vec.drain(..).rev() {
+ vec2.push(i);
+ }
+ assert_eq!(vec, []);
+ assert_eq!(vec2, [3, 2, 1]);
+ }
+
+ #[test]
+ fn test_drain_items_zero_sized() {
+ let mut vec = thin_vec![(), (), ()];
+ let mut vec2 = thin_vec![];
+ for i in vec.drain(..) {
+ vec2.push(i);
+ }
+ assert_eq!(vec, []);
+ assert_eq!(vec2, [(), (), ()]);
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_drain_out_of_bounds() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ v.drain(5..6);
+ }
+
+ #[test]
+ fn test_drain_range() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ for _ in v.drain(4..) {}
+ assert_eq!(v, &[1, 2, 3, 4]);
+
+ let mut v: ThinVec<_> = (1..6).map(|x| x.to_string()).collect();
+ for _ in v.drain(1..4) {}
+ assert_eq!(v, &[1.to_string(), 5.to_string()]);
+
+ let mut v: ThinVec<_> = (1..6).map(|x| x.to_string()).collect();
+ for _ in v.drain(1..4).rev() {}
+ assert_eq!(v, &[1.to_string(), 5.to_string()]);
+
+ let mut v: ThinVec<_> = thin_vec![(); 5];
+ for _ in v.drain(1..4).rev() {}
+ assert_eq!(v, &[(), ()]);
+ }
+
+ #[test]
+ fn test_drain_max_vec_size() {
+ let mut v = ThinVec::<()>::with_capacity(MAX_CAP);
+ unsafe {
+ v.set_len(MAX_CAP);
+ }
+ for _ in v.drain(MAX_CAP - 1..) {}
+ assert_eq!(v.len(), MAX_CAP - 1);
+ }
+
+ #[test]
+ fn test_clear() {
+ let mut v = ThinVec::<i32>::new();
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+
+ v.clear();
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+
+ v.push(1);
+ v.push(2);
+ assert_eq!(v.len(), 2);
+ assert!(v.capacity() >= 2);
+ assert_eq!(&v[..], &[1, 2]);
+
+ v.clear();
+ assert_eq!(v.len(), 0);
+ assert!(v.capacity() >= 2);
+ assert_eq!(&v[..], &[]);
+
+ v.push(3);
+ v.push(4);
+ assert_eq!(v.len(), 2);
+ assert!(v.capacity() >= 2);
+ assert_eq!(&v[..], &[3, 4]);
+
+ v.clear();
+ assert_eq!(v.len(), 0);
+ assert!(v.capacity() >= 2);
+ assert_eq!(&v[..], &[]);
+
+ v.clear();
+ assert_eq!(v.len(), 0);
+ assert!(v.capacity() >= 2);
+ assert_eq!(&v[..], &[]);
+ }
+
+ #[test]
+ fn test_empty_singleton_torture() {
+ {
+ let mut v = ThinVec::<i32>::new();
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert!(v.is_empty());
+ assert_eq!(&v[..], &[]);
+ assert_eq!(&mut v[..], &mut []);
+
+ assert_eq!(v.pop(), None);
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let v = ThinVec::<i32>::new();
+ assert_eq!(v.into_iter().count(), 0);
+
+ let v = ThinVec::<i32>::new();
+ for _ in v.into_iter() {
+ unreachable!();
+ }
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ assert_eq!(v.drain(..).len(), 0);
+
+ for _ in v.drain(..) {
+ unreachable!()
+ }
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ assert_eq!(v.splice(.., []).len(), 0);
+
+ for _ in v.splice(.., []) {
+ unreachable!()
+ }
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ v.truncate(1);
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+
+ v.truncate(0);
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ v.shrink_to_fit();
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ let new = v.split_off(0);
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+
+ assert_eq!(new.len(), 0);
+ assert_eq!(new.capacity(), 0);
+ assert_eq!(&new[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ let mut other = ThinVec::<i32>::new();
+ v.append(&mut other);
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+
+ assert_eq!(other.len(), 0);
+ assert_eq!(other.capacity(), 0);
+ assert_eq!(&other[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ v.reserve(0);
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ v.reserve_exact(0);
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ v.reserve(0);
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let v = ThinVec::<i32>::with_capacity(0);
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let v = ThinVec::<i32>::default();
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ v.retain(|_| unreachable!());
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ v.retain_mut(|_| unreachable!());
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ v.dedup_by_key(|x| *x);
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let mut v = ThinVec::<i32>::new();
+ v.dedup_by(|_, _| unreachable!());
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+
+ {
+ let v = ThinVec::<i32>::new();
+ let v = v.clone();
+
+ assert_eq!(v.len(), 0);
+ assert_eq!(v.capacity(), 0);
+ assert_eq!(&v[..], &[]);
+ }
+ }
+
+ #[test]
+ fn test_clone() {
+ let mut v = ThinVec::<i32>::new();
+ assert!(v.is_singleton());
+ v.push(0);
+ v.pop();
+ assert!(!v.is_singleton());
+
+ let v2 = v.clone();
+ assert!(v2.is_singleton());
+ }
+}
+
+#[cfg(test)]
+mod std_tests {
+ #![allow(clippy::reversed_empty_ranges)]
+
+ use super::*;
+ use std::mem::size_of;
+ use std::usize;
+
+ struct DropCounter<'a> {
+ count: &'a mut u32,
+ }
+
+ impl<'a> Drop for DropCounter<'a> {
+ fn drop(&mut self) {
+ *self.count += 1;
+ }
+ }
+
+ #[test]
+ fn test_small_vec_struct() {
+ assert!(size_of::<ThinVec<u8>>() == size_of::<usize>());
+ }
+
+ #[test]
+ fn test_double_drop() {
+ struct TwoVec<T> {
+ x: ThinVec<T>,
+ y: ThinVec<T>,
+ }
+
+ let (mut count_x, mut count_y) = (0, 0);
+ {
+ let mut tv = TwoVec {
+ x: ThinVec::new(),
+ y: ThinVec::new(),
+ };
+ tv.x.push(DropCounter {
+ count: &mut count_x,
+ });
+ tv.y.push(DropCounter {
+ count: &mut count_y,
+ });
+
+ // If ThinVec had a drop flag, here is where it would be zeroed.
+ // Instead, it should rely on its internal state to prevent
+ // doing anything significant when dropped multiple times.
+ drop(tv.x);
+
+ // Here tv goes out of scope, tv.y should be dropped, but not tv.x.
+ }
+
+ assert_eq!(count_x, 1);
+ assert_eq!(count_y, 1);
+ }
+
+ #[test]
+ fn test_reserve() {
+ let mut v = ThinVec::new();
+ assert_eq!(v.capacity(), 0);
+
+ v.reserve(2);
+ assert!(v.capacity() >= 2);
+
+ for i in 0..16 {
+ v.push(i);
+ }
+
+ assert!(v.capacity() >= 16);
+ v.reserve(16);
+ assert!(v.capacity() >= 32);
+
+ v.push(16);
+
+ v.reserve(16);
+ assert!(v.capacity() >= 33)
+ }
+
+ #[test]
+ fn test_extend() {
+ let mut v = ThinVec::<usize>::new();
+ let mut w = ThinVec::new();
+ v.extend(w.clone());
+ assert_eq!(v, &[]);
+
+ v.extend(0..3);
+ for i in 0..3 {
+ w.push(i)
+ }
+
+ assert_eq!(v, w);
+
+ v.extend(3..10);
+ for i in 3..10 {
+ w.push(i)
+ }
+
+ assert_eq!(v, w);
+
+ v.extend(w.clone()); // specializes to `append`
+ assert!(v.iter().eq(w.iter().chain(w.iter())));
+
+ // Zero sized types
+ #[derive(PartialEq, Debug)]
+ struct Foo;
+
+ let mut a = ThinVec::new();
+ let b = thin_vec![Foo, Foo];
+
+ a.extend(b);
+ assert_eq!(a, &[Foo, Foo]);
+
+ // Double drop
+ let mut count_x = 0;
+ {
+ let mut x = ThinVec::new();
+ let y = thin_vec![DropCounter {
+ count: &mut count_x
+ }];
+ x.extend(y);
+ }
+
+ assert_eq!(count_x, 1);
+ }
+
+ /* TODO: implement extend for Iter<&Copy>
+ #[test]
+ fn test_extend_ref() {
+ let mut v = thin_vec![1, 2];
+ v.extend(&[3, 4, 5]);
+
+ assert_eq!(v.len(), 5);
+ assert_eq!(v, [1, 2, 3, 4, 5]);
+
+ let w = thin_vec![6, 7];
+ v.extend(&w);
+
+ assert_eq!(v.len(), 7);
+ assert_eq!(v, [1, 2, 3, 4, 5, 6, 7]);
+ }
+ */
+
+ #[test]
+ fn test_slice_from_mut() {
+ let mut values = thin_vec![1, 2, 3, 4, 5];
+ {
+ let slice = &mut values[2..];
+ assert!(slice == [3, 4, 5]);
+ for p in slice {
+ *p += 2;
+ }
+ }
+
+ assert!(values == [1, 2, 5, 6, 7]);
+ }
+
+ #[test]
+ fn test_slice_to_mut() {
+ let mut values = thin_vec![1, 2, 3, 4, 5];
+ {
+ let slice = &mut values[..2];
+ assert!(slice == [1, 2]);
+ for p in slice {
+ *p += 1;
+ }
+ }
+
+ assert!(values == [2, 3, 3, 4, 5]);
+ }
+
+ #[test]
+ fn test_split_at_mut() {
+ let mut values = thin_vec![1, 2, 3, 4, 5];
+ {
+ let (left, right) = values.split_at_mut(2);
+ {
+ let left: &[_] = left;
+ assert!(left[..left.len()] == [1, 2]);
+ }
+ for p in left {
+ *p += 1;
+ }
+
+ {
+ let right: &[_] = right;
+ assert!(right[..right.len()] == [3, 4, 5]);
+ }
+ for p in right {
+ *p += 2;
+ }
+ }
+
+ assert_eq!(values, [2, 3, 5, 6, 7]);
+ }
+
+ #[test]
+ fn test_clone() {
+ let v: ThinVec<i32> = thin_vec![];
+ let w = thin_vec![1, 2, 3];
+
+ assert_eq!(v, v.clone());
+
+ let z = w.clone();
+ assert_eq!(w, z);
+ // they should be disjoint in memory.
+ assert!(w.as_ptr() != z.as_ptr())
+ }
+
+ #[test]
+ fn test_clone_from() {
+ let mut v = thin_vec![];
+ let three: ThinVec<Box<_>> = thin_vec![Box::new(1), Box::new(2), Box::new(3)];
+ let two: ThinVec<Box<_>> = thin_vec![Box::new(4), Box::new(5)];
+ // zero, long
+ v.clone_from(&three);
+ assert_eq!(v, three);
+
+ // equal
+ v.clone_from(&three);
+ assert_eq!(v, three);
+
+ // long, short
+ v.clone_from(&two);
+ assert_eq!(v, two);
+
+ // short, long
+ v.clone_from(&three);
+ assert_eq!(v, three)
+ }
+
+ #[test]
+ fn test_retain() {
+ let mut vec = thin_vec![1, 2, 3, 4];
+ vec.retain(|&x| x % 2 == 0);
+ assert_eq!(vec, [2, 4]);
+ }
+
+ #[test]
+ fn test_retain_mut() {
+ let mut vec = thin_vec![9, 9, 9, 9];
+ let mut i = 0;
+ vec.retain_mut(|x| {
+ i += 1;
+ *x = i;
+ i != 4
+ });
+ assert_eq!(vec, [1, 2, 3]);
+ }
+
+ #[test]
+ fn test_dedup() {
+ fn case(a: ThinVec<i32>, b: ThinVec<i32>) {
+ let mut v = a;
+ v.dedup();
+ assert_eq!(v, b);
+ }
+ case(thin_vec![], thin_vec![]);
+ case(thin_vec![1], thin_vec![1]);
+ case(thin_vec![1, 1], thin_vec![1]);
+ case(thin_vec![1, 2, 3], thin_vec![1, 2, 3]);
+ case(thin_vec![1, 1, 2, 3], thin_vec![1, 2, 3]);
+ case(thin_vec![1, 2, 2, 3], thin_vec![1, 2, 3]);
+ case(thin_vec![1, 2, 3, 3], thin_vec![1, 2, 3]);
+ case(thin_vec![1, 1, 2, 2, 2, 3, 3], thin_vec![1, 2, 3]);
+ }
+
+ #[test]
+ fn test_dedup_by_key() {
+ fn case(a: ThinVec<i32>, b: ThinVec<i32>) {
+ let mut v = a;
+ v.dedup_by_key(|i| *i / 10);
+ assert_eq!(v, b);
+ }
+ case(thin_vec![], thin_vec![]);
+ case(thin_vec![10], thin_vec![10]);
+ case(thin_vec![10, 11], thin_vec![10]);
+ case(thin_vec![10, 20, 30], thin_vec![10, 20, 30]);
+ case(thin_vec![10, 11, 20, 30], thin_vec![10, 20, 30]);
+ case(thin_vec![10, 20, 21, 30], thin_vec![10, 20, 30]);
+ case(thin_vec![10, 20, 30, 31], thin_vec![10, 20, 30]);
+ case(thin_vec![10, 11, 20, 21, 22, 30, 31], thin_vec![10, 20, 30]);
+ }
+
+ #[test]
+ fn test_dedup_by() {
+ let mut vec = thin_vec!["foo", "bar", "Bar", "baz", "bar"];
+ vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b));
+
+ assert_eq!(vec, ["foo", "bar", "baz", "bar"]);
+
+ let mut vec = thin_vec![("foo", 1), ("foo", 2), ("bar", 3), ("bar", 4), ("bar", 5)];
+ vec.dedup_by(|a, b| {
+ a.0 == b.0 && {
+ b.1 += a.1;
+ true
+ }
+ });
+
+ assert_eq!(vec, [("foo", 3), ("bar", 12)]);
+ }
+
+ #[test]
+ fn test_dedup_unique() {
+ let mut v0: ThinVec<Box<_>> = thin_vec![Box::new(1), Box::new(1), Box::new(2), Box::new(3)];
+ v0.dedup();
+ let mut v1: ThinVec<Box<_>> = thin_vec![Box::new(1), Box::new(2), Box::new(2), Box::new(3)];
+ v1.dedup();
+ let mut v2: ThinVec<Box<_>> = thin_vec![Box::new(1), Box::new(2), Box::new(3), Box::new(3)];
+ v2.dedup();
+ // If the boxed pointers were leaked or otherwise misused, valgrind
+ // and/or rt should raise errors.
+ }
+
+ #[test]
+ fn zero_sized_values() {
+ let mut v = ThinVec::new();
+ assert_eq!(v.len(), 0);
+ v.push(());
+ assert_eq!(v.len(), 1);
+ v.push(());
+ assert_eq!(v.len(), 2);
+ assert_eq!(v.pop(), Some(()));
+ assert_eq!(v.pop(), Some(()));
+ assert_eq!(v.pop(), None);
+
+ assert_eq!(v.iter().count(), 0);
+ v.push(());
+ assert_eq!(v.iter().count(), 1);
+ v.push(());
+ assert_eq!(v.iter().count(), 2);
+
+ for &() in &v {}
+
+ assert_eq!(v.iter_mut().count(), 2);
+ v.push(());
+ assert_eq!(v.iter_mut().count(), 3);
+ v.push(());
+ assert_eq!(v.iter_mut().count(), 4);
+
+ for &mut () in &mut v {}
+ unsafe {
+ v.set_len(0);
+ }
+ assert_eq!(v.iter_mut().count(), 0);
+ }
+
+ #[test]
+ fn test_partition() {
+ assert_eq!(
+ thin_vec![].into_iter().partition(|x: &i32| *x < 3),
+ (thin_vec![], thin_vec![])
+ );
+ assert_eq!(
+ thin_vec![1, 2, 3].into_iter().partition(|x| *x < 4),
+ (thin_vec![1, 2, 3], thin_vec![])
+ );
+ assert_eq!(
+ thin_vec![1, 2, 3].into_iter().partition(|x| *x < 2),
+ (thin_vec![1], thin_vec![2, 3])
+ );
+ assert_eq!(
+ thin_vec![1, 2, 3].into_iter().partition(|x| *x < 0),
+ (thin_vec![], thin_vec![1, 2, 3])
+ );
+ }
+
+ #[test]
+ fn test_zip_unzip() {
+ let z1 = thin_vec![(1, 4), (2, 5), (3, 6)];
+
+ let (left, right): (ThinVec<_>, ThinVec<_>) = z1.iter().cloned().unzip();
+
+ assert_eq!((1, 4), (left[0], right[0]));
+ assert_eq!((2, 5), (left[1], right[1]));
+ assert_eq!((3, 6), (left[2], right[2]));
+ }
+
+ #[test]
+ fn test_vec_truncate_drop() {
+ static mut DROPS: u32 = 0;
+ struct Elem(i32);
+ impl Drop for Elem {
+ fn drop(&mut self) {
+ unsafe {
+ DROPS += 1;
+ }
+ }
+ }
+
+ let mut v = thin_vec![Elem(1), Elem(2), Elem(3), Elem(4), Elem(5)];
+ assert_eq!(unsafe { DROPS }, 0);
+ v.truncate(3);
+ assert_eq!(unsafe { DROPS }, 2);
+ v.truncate(0);
+ assert_eq!(unsafe { DROPS }, 5);
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_vec_truncate_fail() {
+ struct BadElem(i32);
+ impl Drop for BadElem {
+ fn drop(&mut self) {
+ let BadElem(ref mut x) = *self;
+ if *x == 0xbadbeef {
+ panic!("BadElem panic: 0xbadbeef")
+ }
+ }
+ }
+
+ let mut v = thin_vec![BadElem(1), BadElem(2), BadElem(0xbadbeef), BadElem(4)];
+ v.truncate(0);
+ }
+
+ #[test]
+ fn test_index() {
+ let vec = thin_vec![1, 2, 3];
+ assert!(vec[1] == 2);
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_index_out_of_bounds() {
+ let vec = thin_vec![1, 2, 3];
+ let _ = vec[3];
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_slice_out_of_bounds_1() {
+ let x = thin_vec![1, 2, 3, 4, 5];
+ let _ = &x[!0..];
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_slice_out_of_bounds_2() {
+ let x = thin_vec![1, 2, 3, 4, 5];
+ let _ = &x[..6];
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_slice_out_of_bounds_3() {
+ let x = thin_vec![1, 2, 3, 4, 5];
+ let _ = &x[!0..4];
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_slice_out_of_bounds_4() {
+ let x = thin_vec![1, 2, 3, 4, 5];
+ let _ = &x[1..6];
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_slice_out_of_bounds_5() {
+ let x = thin_vec![1, 2, 3, 4, 5];
+ let _ = &x[3..2];
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_swap_remove_empty() {
+ let mut vec = ThinVec::<i32>::new();
+ vec.swap_remove(0);
+ }
+
+ #[test]
+ fn test_move_items() {
+ let vec = thin_vec![1, 2, 3];
+ let mut vec2 = thin_vec![];
+ for i in vec {
+ vec2.push(i);
+ }
+ assert_eq!(vec2, [1, 2, 3]);
+ }
+
+ #[test]
+ fn test_move_items_reverse() {
+ let vec = thin_vec![1, 2, 3];
+ let mut vec2 = thin_vec![];
+ for i in vec.into_iter().rev() {
+ vec2.push(i);
+ }
+ assert_eq!(vec2, [3, 2, 1]);
+ }
+
+ #[test]
+ fn test_move_items_zero_sized() {
+ let vec = thin_vec![(), (), ()];
+ let mut vec2 = thin_vec![];
+ for i in vec {
+ vec2.push(i);
+ }
+ assert_eq!(vec2, [(), (), ()]);
+ }
+
+ #[test]
+ fn test_drain_items() {
+ let mut vec = thin_vec![1, 2, 3];
+ let mut vec2 = thin_vec![];
+ for i in vec.drain(..) {
+ vec2.push(i);
+ }
+ assert_eq!(vec, []);
+ assert_eq!(vec2, [1, 2, 3]);
+ }
+
+ #[test]
+ fn test_drain_items_reverse() {
+ let mut vec = thin_vec![1, 2, 3];
+ let mut vec2 = thin_vec![];
+ for i in vec.drain(..).rev() {
+ vec2.push(i);
+ }
+ assert_eq!(vec, []);
+ assert_eq!(vec2, [3, 2, 1]);
+ }
+
+ #[test]
+ fn test_drain_items_zero_sized() {
+ let mut vec = thin_vec![(), (), ()];
+ let mut vec2 = thin_vec![];
+ for i in vec.drain(..) {
+ vec2.push(i);
+ }
+ assert_eq!(vec, []);
+ assert_eq!(vec2, [(), (), ()]);
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_drain_out_of_bounds() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ v.drain(5..6);
+ }
+
+ #[test]
+ fn test_drain_range() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ for _ in v.drain(4..) {}
+ assert_eq!(v, &[1, 2, 3, 4]);
+
+ let mut v: ThinVec<_> = (1..6).map(|x| x.to_string()).collect();
+ for _ in v.drain(1..4) {}
+ assert_eq!(v, &[1.to_string(), 5.to_string()]);
+
+ let mut v: ThinVec<_> = (1..6).map(|x| x.to_string()).collect();
+ for _ in v.drain(1..4).rev() {}
+ assert_eq!(v, &[1.to_string(), 5.to_string()]);
+
+ let mut v: ThinVec<_> = thin_vec![(); 5];
+ for _ in v.drain(1..4).rev() {}
+ assert_eq!(v, &[(), ()]);
+ }
+
+ #[test]
+ fn test_drain_inclusive_range() {
+ let mut v = thin_vec!['a', 'b', 'c', 'd', 'e'];
+ for _ in v.drain(1..=3) {}
+ assert_eq!(v, &['a', 'e']);
+
+ let mut v: ThinVec<_> = (0..=5).map(|x| x.to_string()).collect();
+ for _ in v.drain(1..=5) {}
+ assert_eq!(v, &["0".to_string()]);
+
+ let mut v: ThinVec<String> = (0..=5).map(|x| x.to_string()).collect();
+ for _ in v.drain(0..=5) {}
+ assert_eq!(v, ThinVec::<String>::new());
+
+ let mut v: ThinVec<_> = (0..=5).map(|x| x.to_string()).collect();
+ for _ in v.drain(0..=3) {}
+ assert_eq!(v, &["4".to_string(), "5".to_string()]);
+
+ let mut v: ThinVec<_> = (0..=1).map(|x| x.to_string()).collect();
+ for _ in v.drain(..=0) {}
+ assert_eq!(v, &["1".to_string()]);
+ }
+
+ #[test]
+ #[cfg(not(feature = "gecko-ffi"))]
+ fn test_drain_max_vec_size() {
+ let mut v = ThinVec::<()>::with_capacity(usize::max_value());
+ unsafe {
+ v.set_len(usize::max_value());
+ }
+ for _ in v.drain(usize::max_value() - 1..) {}
+ assert_eq!(v.len(), usize::max_value() - 1);
+
+ let mut v = ThinVec::<()>::with_capacity(usize::max_value());
+ unsafe {
+ v.set_len(usize::max_value());
+ }
+ for _ in v.drain(usize::max_value() - 1..=usize::max_value() - 1) {}
+ assert_eq!(v.len(), usize::max_value() - 1);
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_drain_inclusive_out_of_bounds() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ v.drain(5..=5);
+ }
+
+ #[test]
+ fn test_splice() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ let a = [10, 11, 12];
+ v.splice(2..4, a.iter().cloned());
+ assert_eq!(v, &[1, 2, 10, 11, 12, 5]);
+ v.splice(1..3, Some(20));
+ assert_eq!(v, &[1, 20, 11, 12, 5]);
+ }
+
+ #[test]
+ fn test_splice_inclusive_range() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ let a = [10, 11, 12];
+ let t1: ThinVec<_> = v.splice(2..=3, a.iter().cloned()).collect();
+ assert_eq!(v, &[1, 2, 10, 11, 12, 5]);
+ assert_eq!(t1, &[3, 4]);
+ let t2: ThinVec<_> = v.splice(1..=2, Some(20)).collect();
+ assert_eq!(v, &[1, 20, 11, 12, 5]);
+ assert_eq!(t2, &[2, 10]);
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_splice_out_of_bounds() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ let a = [10, 11, 12];
+ v.splice(5..6, a.iter().cloned());
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_splice_inclusive_out_of_bounds() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ let a = [10, 11, 12];
+ v.splice(5..=5, a.iter().cloned());
+ }
+
+ #[test]
+ fn test_splice_items_zero_sized() {
+ let mut vec = thin_vec![(), (), ()];
+ let vec2 = thin_vec![];
+ let t: ThinVec<_> = vec.splice(1..2, vec2.iter().cloned()).collect();
+ assert_eq!(vec, &[(), ()]);
+ assert_eq!(t, &[()]);
+ }
+
+ #[test]
+ fn test_splice_unbounded() {
+ let mut vec = thin_vec![1, 2, 3, 4, 5];
+ let t: ThinVec<_> = vec.splice(.., None).collect();
+ assert_eq!(vec, &[]);
+ assert_eq!(t, &[1, 2, 3, 4, 5]);
+ }
+
+ #[test]
+ fn test_splice_forget() {
+ let mut v = thin_vec![1, 2, 3, 4, 5];
+ let a = [10, 11, 12];
+ ::std::mem::forget(v.splice(2..4, a.iter().cloned()));
+ assert_eq!(v, &[1, 2]);
+ }
+
+ #[test]
+ fn test_splice_from_empty() {
+ let mut v = thin_vec![];
+ let a = [10, 11, 12];
+ v.splice(.., a.iter().cloned());
+ assert_eq!(v, &[10, 11, 12]);
+ }
+
+ /* probs won't ever impl this
+ #[test]
+ fn test_into_boxed_slice() {
+ let xs = thin_vec![1, 2, 3];
+ let ys = xs.into_boxed_slice();
+ assert_eq!(&*ys, [1, 2, 3]);
+ }
+ */
+
+ #[test]
+ fn test_append() {
+ let mut vec = thin_vec![1, 2, 3];
+ let mut vec2 = thin_vec![4, 5, 6];
+ vec.append(&mut vec2);
+ assert_eq!(vec, [1, 2, 3, 4, 5, 6]);
+ assert_eq!(vec2, []);
+ }
+
+ #[test]
+ fn test_split_off() {
+ let mut vec = thin_vec![1, 2, 3, 4, 5, 6];
+ let vec2 = vec.split_off(4);
+ assert_eq!(vec, [1, 2, 3, 4]);
+ assert_eq!(vec2, [5, 6]);
+ }
+
+ #[test]
+ fn test_into_iter_as_slice() {
+ let vec = thin_vec!['a', 'b', 'c'];
+ let mut into_iter = vec.into_iter();
+ assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+ let _ = into_iter.next().unwrap();
+ assert_eq!(into_iter.as_slice(), &['b', 'c']);
+ let _ = into_iter.next().unwrap();
+ let _ = into_iter.next().unwrap();
+ assert_eq!(into_iter.as_slice(), &[]);
+ }
+
+ #[test]
+ fn test_into_iter_as_mut_slice() {
+ let vec = thin_vec!['a', 'b', 'c'];
+ let mut into_iter = vec.into_iter();
+ assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+ into_iter.as_mut_slice()[0] = 'x';
+ into_iter.as_mut_slice()[1] = 'y';
+ assert_eq!(into_iter.next().unwrap(), 'x');
+ assert_eq!(into_iter.as_slice(), &['y', 'c']);
+ }
+
+ #[test]
+ fn test_into_iter_debug() {
+ let vec = thin_vec!['a', 'b', 'c'];
+ let into_iter = vec.into_iter();
+ let debug = format!("{:?}", into_iter);
+ assert_eq!(debug, "IntoIter(['a', 'b', 'c'])");
+ }
+
+ #[test]
+ fn test_into_iter_count() {
+ assert_eq!(thin_vec![1, 2, 3].into_iter().count(), 3);
+ }
+
+ #[test]
+ fn test_into_iter_clone() {
+ fn iter_equal<I: Iterator<Item = i32>>(it: I, slice: &[i32]) {
+ let v: ThinVec<i32> = it.collect();
+ assert_eq!(&v[..], slice);
+ }
+ let mut it = thin_vec![1, 2, 3].into_iter();
+ iter_equal(it.clone(), &[1, 2, 3]);
+ assert_eq!(it.next(), Some(1));
+ let mut it = it.rev();
+ iter_equal(it.clone(), &[3, 2]);
+ assert_eq!(it.next(), Some(3));
+ iter_equal(it.clone(), &[2]);
+ assert_eq!(it.next(), Some(2));
+ iter_equal(it.clone(), &[]);
+ assert_eq!(it.next(), None);
+ }
+
+ /* TODO: make drain covariant
+ #[allow(dead_code)]
+ fn assert_covariance() {
+ fn drain<'new>(d: Drain<'static, &'static str>) -> Drain<'new, &'new str> {
+ d
+ }
+ fn into_iter<'new>(i: IntoIter<&'static str>) -> IntoIter<&'new str> {
+ i
+ }
+ }
+ */
+
+ /* TODO: specialize vec.into_iter().collect::<ThinVec<_>>();
+ #[test]
+ fn from_into_inner() {
+ let vec = thin_vec![1, 2, 3];
+ let ptr = vec.as_ptr();
+ let vec = vec.into_iter().collect::<ThinVec<_>>();
+ assert_eq!(vec, [1, 2, 3]);
+ assert_eq!(vec.as_ptr(), ptr);
+
+ let ptr = &vec[1] as *const _;
+ let mut it = vec.into_iter();
+ it.next().unwrap();
+ let vec = it.collect::<ThinVec<_>>();
+ assert_eq!(vec, [2, 3]);
+ assert!(ptr != vec.as_ptr());
+ }
+ */
+
+ #[test]
+ #[cfg_attr(feature = "gecko-ffi", ignore)]
+ fn overaligned_allocations() {
+ #[repr(align(256))]
+ struct Foo(usize);
+ let mut v = thin_vec![Foo(273)];
+ for i in 0..0x1000 {
+ v.reserve_exact(i);
+ assert!(v[0].0 == 273);
+ assert!(v.as_ptr() as usize & 0xff == 0);
+ v.shrink_to_fit();
+ assert!(v[0].0 == 273);
+ assert!(v.as_ptr() as usize & 0xff == 0);
+ }
+ }
+
+ /* TODO: implement drain_filter?
+ #[test]
+ fn drain_filter_empty() {
+ let mut vec: ThinVec<i32> = thin_vec![];
+
+ {
+ let mut iter = vec.drain_filter(|_| true);
+ assert_eq!(iter.size_hint(), (0, Some(0)));
+ assert_eq!(iter.next(), None);
+ assert_eq!(iter.size_hint(), (0, Some(0)));
+ assert_eq!(iter.next(), None);
+ assert_eq!(iter.size_hint(), (0, Some(0)));
+ }
+ assert_eq!(vec.len(), 0);
+ assert_eq!(vec, thin_vec![]);
+ }
+
+ #[test]
+ fn drain_filter_zst() {
+ let mut vec = thin_vec![(), (), (), (), ()];
+ let initial_len = vec.len();
+ let mut count = 0;
+ {
+ let mut iter = vec.drain_filter(|_| true);
+ assert_eq!(iter.size_hint(), (0, Some(initial_len)));
+ while let Some(_) = iter.next() {
+ count += 1;
+ assert_eq!(iter.size_hint(), (0, Some(initial_len - count)));
+ }
+ assert_eq!(iter.size_hint(), (0, Some(0)));
+ assert_eq!(iter.next(), None);
+ assert_eq!(iter.size_hint(), (0, Some(0)));
+ }
+
+ assert_eq!(count, initial_len);
+ assert_eq!(vec.len(), 0);
+ assert_eq!(vec, thin_vec![]);
+ }
+
+ #[test]
+ fn drain_filter_false() {
+ let mut vec = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+ let initial_len = vec.len();
+ let mut count = 0;
+ {
+ let mut iter = vec.drain_filter(|_| false);
+ assert_eq!(iter.size_hint(), (0, Some(initial_len)));
+ for _ in iter.by_ref() {
+ count += 1;
+ }
+ assert_eq!(iter.size_hint(), (0, Some(0)));
+ assert_eq!(iter.next(), None);
+ assert_eq!(iter.size_hint(), (0, Some(0)));
+ }
+
+ assert_eq!(count, 0);
+ assert_eq!(vec.len(), initial_len);
+ assert_eq!(vec, thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+ }
+
+ #[test]
+ fn drain_filter_true() {
+ let mut vec = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+ let initial_len = vec.len();
+ let mut count = 0;
+ {
+ let mut iter = vec.drain_filter(|_| true);
+ assert_eq!(iter.size_hint(), (0, Some(initial_len)));
+ while let Some(_) = iter.next() {
+ count += 1;
+ assert_eq!(iter.size_hint(), (0, Some(initial_len - count)));
+ }
+ assert_eq!(iter.size_hint(), (0, Some(0)));
+ assert_eq!(iter.next(), None);
+ assert_eq!(iter.size_hint(), (0, Some(0)));
+ }
+
+ assert_eq!(count, initial_len);
+ assert_eq!(vec.len(), 0);
+ assert_eq!(vec, thin_vec![]);
+ }
+
+ #[test]
+ fn drain_filter_complex() {
+
+ { // [+xxx++++++xxxxx++++x+x++]
+ let mut vec = thin_vec![1,
+ 2, 4, 6,
+ 7, 9, 11, 13, 15, 17,
+ 18, 20, 22, 24, 26,
+ 27, 29, 31, 33,
+ 34,
+ 35,
+ 36,
+ 37, 39];
+
+ let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>();
+ assert_eq!(removed.len(), 10);
+ assert_eq!(removed, thin_vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
+
+ assert_eq!(vec.len(), 14);
+ assert_eq!(vec, thin_vec![1, 7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35, 37, 39]);
+ }
+
+ { // [xxx++++++xxxxx++++x+x++]
+ let mut vec = thin_vec![2, 4, 6,
+ 7, 9, 11, 13, 15, 17,
+ 18, 20, 22, 24, 26,
+ 27, 29, 31, 33,
+ 34,
+ 35,
+ 36,
+ 37, 39];
+
+ let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>();
+ assert_eq!(removed.len(), 10);
+ assert_eq!(removed, thin_vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
+
+ assert_eq!(vec.len(), 13);
+ assert_eq!(vec, thin_vec![7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35, 37, 39]);
+ }
+
+ { // [xxx++++++xxxxx++++x+x]
+ let mut vec = thin_vec![2, 4, 6,
+ 7, 9, 11, 13, 15, 17,
+ 18, 20, 22, 24, 26,
+ 27, 29, 31, 33,
+ 34,
+ 35,
+ 36];
+
+ let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>();
+ assert_eq!(removed.len(), 10);
+ assert_eq!(removed, thin_vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
+
+ assert_eq!(vec.len(), 11);
+ assert_eq!(vec, thin_vec![7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35]);
+ }
+
+ { // [xxxxxxxxxx+++++++++++]
+ let mut vec = thin_vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20,
+ 1, 3, 5, 7, 9, 11, 13, 15, 17, 19];
+
+ let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>();
+ assert_eq!(removed.len(), 10);
+ assert_eq!(removed, thin_vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]);
+
+ assert_eq!(vec.len(), 10);
+ assert_eq!(vec, thin_vec![1, 3, 5, 7, 9, 11, 13, 15, 17, 19]);
+ }
+
+ { // [+++++++++++xxxxxxxxxx]
+ let mut vec = thin_vec![1, 3, 5, 7, 9, 11, 13, 15, 17, 19,
+ 2, 4, 6, 8, 10, 12, 14, 16, 18, 20];
+
+ let removed = vec.drain_filter(|x| *x % 2 == 0).collect::<ThinVec<_>>();
+ assert_eq!(removed.len(), 10);
+ assert_eq!(removed, thin_vec![2, 4, 6, 8, 10, 12, 14, 16, 18, 20]);
+
+ assert_eq!(vec.len(), 10);
+ assert_eq!(vec, thin_vec![1, 3, 5, 7, 9, 11, 13, 15, 17, 19]);
+ }
+ }
+ */
+ #[test]
+ fn test_reserve_exact() {
+ // This is all the same as test_reserve
+
+ let mut v = ThinVec::new();
+ assert_eq!(v.capacity(), 0);
+
+ v.reserve_exact(2);
+ assert!(v.capacity() >= 2);
+
+ for i in 0..16 {
+ v.push(i);
+ }
+
+ assert!(v.capacity() >= 16);
+ v.reserve_exact(16);
+ assert!(v.capacity() >= 32);
+
+ v.push(16);
+
+ v.reserve_exact(16);
+ assert!(v.capacity() >= 33)
+ }
+
+ /* TODO: implement try_reserve
+ #[test]
+ fn test_try_reserve() {
+
+ // These are the interesting cases:
+ // * exactly isize::MAX should never trigger a CapacityOverflow (can be OOM)
+ // * > isize::MAX should always fail
+ // * On 16/32-bit should CapacityOverflow
+ // * On 64-bit should OOM
+ // * overflow may trigger when adding `len` to `cap` (in number of elements)
+ // * overflow may trigger when multiplying `new_cap` by size_of::<T> (to get bytes)
+
+ const MAX_CAP: usize = isize::MAX as usize;
+ const MAX_USIZE: usize = usize::MAX;
+
+ // On 16/32-bit, we check that allocations don't exceed isize::MAX,
+ // on 64-bit, we assume the OS will give an OOM for such a ridiculous size.
+ // Any platform that succeeds for these requests is technically broken with
+ // ptr::offset because LLVM is the worst.
+ let guards_against_isize = size_of::<usize>() < 8;
+
+ {
+ // Note: basic stuff is checked by test_reserve
+ let mut empty_bytes: ThinVec<u8> = ThinVec::new();
+
+ // Check isize::MAX doesn't count as an overflow
+ if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_CAP) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ // Play it again, frank! (just to be sure)
+ if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_CAP) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+
+ if guards_against_isize {
+ // Check isize::MAX + 1 does count as overflow
+ if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_CAP + 1) {
+ } else { panic!("isize::MAX + 1 should trigger an overflow!") }
+
+ // Check usize::MAX does count as overflow
+ if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_USIZE) {
+ } else { panic!("usize::MAX should trigger an overflow!") }
+ } else {
+ // Check isize::MAX + 1 is an OOM
+ if let Err(AllocErr) = empty_bytes.try_reserve(MAX_CAP + 1) {
+ } else { panic!("isize::MAX + 1 should trigger an OOM!") }
+
+ // Check usize::MAX is an OOM
+ if let Err(AllocErr) = empty_bytes.try_reserve(MAX_USIZE) {
+ } else { panic!("usize::MAX should trigger an OOM!") }
+ }
+ }
+
+
+ {
+ // Same basic idea, but with non-zero len
+ let mut ten_bytes: ThinVec<u8> = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+ if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 10) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 10) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ if guards_against_isize {
+ if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 9) {
+ } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
+ } else {
+ if let Err(AllocErr) = ten_bytes.try_reserve(MAX_CAP - 9) {
+ } else { panic!("isize::MAX + 1 should trigger an OOM!") }
+ }
+ // Should always overflow in the add-to-len
+ if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_USIZE) {
+ } else { panic!("usize::MAX should trigger an overflow!") }
+ }
+
+
+ {
+ // Same basic idea, but with interesting type size
+ let mut ten_u32s: ThinVec<u32> = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+ if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 10) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 10) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ if guards_against_isize {
+ if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
+ } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
+ } else {
+ if let Err(AllocErr) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
+ } else { panic!("isize::MAX + 1 should trigger an OOM!") }
+ }
+ // Should fail in the mul-by-size
+ if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_USIZE - 20) {
+ } else {
+ panic!("usize::MAX should trigger an overflow!");
+ }
+ }
+
+ }
+
+ #[test]
+ fn test_try_reserve_exact() {
+
+ // This is exactly the same as test_try_reserve with the method changed.
+ // See that test for comments.
+
+ const MAX_CAP: usize = isize::MAX as usize;
+ const MAX_USIZE: usize = usize::MAX;
+
+ let guards_against_isize = size_of::<usize>() < 8;
+
+ {
+ let mut empty_bytes: ThinVec<u8> = ThinVec::new();
+
+ if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_CAP) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_CAP) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+
+ if guards_against_isize {
+ if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_CAP + 1) {
+ } else { panic!("isize::MAX + 1 should trigger an overflow!") }
+
+ if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_USIZE) {
+ } else { panic!("usize::MAX should trigger an overflow!") }
+ } else {
+ if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_CAP + 1) {
+ } else { panic!("isize::MAX + 1 should trigger an OOM!") }
+
+ if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_USIZE) {
+ } else { panic!("usize::MAX should trigger an OOM!") }
+ }
+ }
+
+
+ {
+ let mut ten_bytes: ThinVec<u8> = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+ if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 10) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 10) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ if guards_against_isize {
+ if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
+ } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
+ } else {
+ if let Err(AllocErr) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
+ } else { panic!("isize::MAX + 1 should trigger an OOM!") }
+ }
+ if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_USIZE) {
+ } else { panic!("usize::MAX should trigger an overflow!") }
+ }
+
+
+ {
+ let mut ten_u32s: ThinVec<u32> = thin_vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+ if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 10) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 10) {
+ panic!("isize::MAX shouldn't trigger an overflow!");
+ }
+ if guards_against_isize {
+ if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
+ } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
+ } else {
+ if let Err(AllocErr) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
+ } else { panic!("isize::MAX + 1 should trigger an OOM!") }
+ }
+ if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_USIZE - 20) {
+ } else { panic!("usize::MAX should trigger an overflow!") }
+ }
+ }
+ */
+
+ #[test]
+ #[cfg_attr(feature = "gecko-ffi", ignore)]
+ fn test_header_data() {
+ macro_rules! assert_aligned_head_ptr {
+ ($typename:ty) => {{
+ let v: ThinVec<$typename> = ThinVec::with_capacity(1 /* ensure allocation */);
+ let head_ptr: *mut $typename = v.data_raw();
+ assert_eq!(
+ head_ptr as usize % std::mem::align_of::<$typename>(),
+ 0,
+ "expected Header::data<{}> to be aligned",
+ stringify!($typename)
+ );
+ }};
+ }
+
+ const HEADER_SIZE: usize = std::mem::size_of::<Header>();
+ assert_eq!(2 * std::mem::size_of::<usize>(), HEADER_SIZE);
+
+ #[repr(C, align(128))]
+ struct Funky<T>(T);
+ assert_eq!(padding::<Funky<()>>(), 128 - HEADER_SIZE);
+ assert_aligned_head_ptr!(Funky<()>);
+
+ assert_eq!(padding::<Funky<u8>>(), 128 - HEADER_SIZE);
+ assert_aligned_head_ptr!(Funky<u8>);
+
+ assert_eq!(padding::<Funky<[(); 1024]>>(), 128 - HEADER_SIZE);
+ assert_aligned_head_ptr!(Funky<[(); 1024]>);
+
+ assert_eq!(padding::<Funky<[*mut usize; 1024]>>(), 128 - HEADER_SIZE);
+ assert_aligned_head_ptr!(Funky<[*mut usize; 1024]>);
+ }
+
+ #[cfg(feature = "serde")]
+ use serde_test::{assert_tokens, Token};
+
+ #[test]
+ #[cfg(feature = "serde")]
+ fn test_ser_de_empty() {
+ let vec = ThinVec::<u32>::new();
+
+ assert_tokens(&vec, &[Token::Seq { len: Some(0) }, Token::SeqEnd]);
+ }
+
+ #[test]
+ #[cfg(feature = "serde")]
+ fn test_ser_de() {
+ let mut vec = ThinVec::<u32>::new();
+ vec.push(20);
+ vec.push(55);
+ vec.push(123);
+
+ assert_tokens(
+ &vec,
+ &[
+ Token::Seq { len: Some(3) },
+ Token::U32(20),
+ Token::U32(55),
+ Token::U32(123),
+ Token::SeqEnd,
+ ],
+ );
+ }
+
+ #[test]
+ fn test_set_len() {
+ let mut vec: ThinVec<u32> = thin_vec![];
+ unsafe {
+ vec.set_len(0); // at one point this caused a crash
+ }
+ }
+
+ #[test]
+ #[should_panic(expected = "invalid set_len(1) on empty ThinVec")]
+ fn test_set_len_invalid() {
+ let mut vec: ThinVec<u32> = thin_vec![];
+ unsafe {
+ vec.set_len(1);
+ }
+ }
+
+ #[test]
+ #[should_panic(expected = "capacity overflow")]
+ fn test_capacity_overflow_header_too_big() {
+ let vec: ThinVec<u8> = ThinVec::with_capacity(isize::MAX as usize - 2);
+ assert!(vec.capacity() > 0);
+ }
+ #[test]
+ #[should_panic(expected = "capacity overflow")]
+ fn test_capacity_overflow_cap_too_big() {
+ let vec: ThinVec<u8> = ThinVec::with_capacity(isize::MAX as usize + 1);
+ assert!(vec.capacity() > 0);
+ }
+ #[test]
+ #[should_panic(expected = "capacity overflow")]
+ fn test_capacity_overflow_size_mul1() {
+ let vec: ThinVec<u16> = ThinVec::with_capacity(isize::MAX as usize + 1);
+ assert!(vec.capacity() > 0);
+ }
+ #[test]
+ #[should_panic(expected = "capacity overflow")]
+ fn test_capacity_overflow_size_mul2() {
+ let vec: ThinVec<u16> = ThinVec::with_capacity(isize::MAX as usize / 2 + 1);
+ assert!(vec.capacity() > 0);
+ }
+ #[test]
+ #[should_panic(expected = "capacity overflow")]
+ fn test_capacity_overflow_cap_really_isnt_isize() {
+ let vec: ThinVec<u8> = ThinVec::with_capacity(isize::MAX as usize);
+ assert!(vec.capacity() > 0);
+ }
+}