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/*! A dynamically-allocated buffer containing a `BitSlice<O, T>` region. You can read the standard library’s [`alloc::vec` module documentation][std] here. This module defines the [`BitVec`] buffer, and all of its associated support code. `BitVec` is equivalent to `Vec<bool>`, in its operation and in its relationship to the `BitSlice` type. Most of the interesting work to be done on a bit-sequence is implemented in `BitSlice`, to which `BitVec` dereferences, and the vector container itself only exists to maintain ownership, implement dynamic resizing, and provide some specializations that cannot safely be done on `BitSlice` alone. [`BitVec`]: struct.BitVec.html [std]: https://doc.rust-lang.org/alloc/vec !*/ #![cfg(feature = "alloc")] use crate::{ boxed::BitBox, index::BitIdx, mem::BitMemory, order::{ BitOrder, Lsb0, }, pointer::BitPtr, slice::BitSlice, store::BitStore, }; use alloc::vec::Vec; use core::{ mem::ManuallyDrop, ptr::NonNull, slice, }; use funty::IsInteger; use tap::{ pipe::Pipe, tap::Tap, }; /** A vector of individual bits, allocated on the heap. This is a managed, heap-allocated, buffer that contains a `BitSlice` region. It is analagous to `Vec<bool>`, and is written to be as close as possible to drop-in replacabale for it. This type contains little interesting behavior in its own right, dereferencing instead to [`BitSlice`] for manipulation of the buffer contents, and serves primarily as an interface to the allocator. If you require statically-allocated, fixed-size, owned buffers, you should use the [`BitArray`] type. Because `BitVec` directly owns its memory, and can guarantee that no other object in a program has access to its buffers, `BitVec` is able to override some behavior from `BitSlice` in more efficient manners. # Documentation All APIs that mirror something in the standard library will have an `Original` section linking to the corresponding item. All APIs that have a different signature or behavior than the original will have an `API Differences` section explaining what has changed, and how to adapt your existing code to the change. These sections look like this: # Original [`Vec<T>`](https://doc.rust-lang.org/alloc/vec/struct.Vec.html) # API Differences The buffer type `Vec<bool>` has no type parameters. `BitVec<O, T>` has the same two type parameters as `BitSlice<O, T>`. Otherwise, `BitVec` is able to implement the full API surface of `Vec<bool>`. # Behavior Because `BitVec` is a fully-owned buffer, it is able to operate on its memory without concern for any other views that may alias. This enables it to specialize some `BitSlice` behavior to be faster or more efficient. # Type Parameters This takes the same two type parameters, `O: BitOrder` and `T: BitStore`, as `BitSlice`. # Safety Like `BitSlice`, `BitVec` is exactly equal in size to `Vec`, and is also absolutely representation-incompatible with it. You must never attempt to type-cast between `Vec<T>` and `BitVec` in any way, nor attempt to modify the memory value of a `BitVec` handle. Doing so will cause allocator and memory errors in your program, likely inducing a panic. Everything in the `BitVec` public API, even the `unsafe` parts, are guaranteed to have no more unsafety than their equivalent items in the standard library. All `unsafe` APIs will have documentation explicitly detailing what the API requires you to uphold in order for it to function safely and correctly. All safe APIs will do so themselves. # Performance The choice of `T: BitStore` type parameter can impact your vector’s performance, as the allocator operates in units of `T` rather than in bits. This means that larger register types will increase the amount of memory reserved in each call to the allocator, meaning fewer calls to `.push()` will actually cause a reällocation. In addition, iteration over the vector is governed by the `BitSlice` characteristics on the type parameter. You are generally better off using larger types when your vector is a data collection rather than a specific I/O protocol buffer. # Macro Construction Heap allocation can only occur at runtime, but the [`bitvec!`] macro will construct an appropriate `BitSlice` buffer at compile-time, and at run-time, only copy the buffer into a heap allocation. [`BitArray`]: ../array/struct.BitArray.html [`BitSlice`]: ../slice/struct.BitSlice.html [`bitvec!`]: ../macro.bitvec.html **/ #[repr(C)] pub struct BitVec<O = Lsb0, T = usize> where O: BitOrder, T: BitStore, { /// Region pointer describing the live portion of the owned buffer. pointer: NonNull<BitSlice<O, T>>, /// Allocated capacity, in elements `T`, of the owned buffer. capacity: usize, } /// Methods specific to `BitVec<_, T>`, and not present on `Vec<T>`. impl<O, T> BitVec<O, T> where O: BitOrder, T: BitStore, { /// Constructs a `BitVec` from a value repeated many times. /// /// This function is equivalent to the `bitvec![O, T; bit; len]` macro call, /// and is in fact the implementation of that macro syntax. /// /// # Parameters /// /// - `bit`: The bit value to which all `len` allocated bits will be set. /// - `len`: The number of live bits in the constructed `BitVec`. /// /// # Returns /// /// A `BitVec` with `len` live bits, all set to `bit`. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let bv = BitVec::<Msb0, u8>::repeat(true, 20); /// assert_eq!(bv, bits![1; 20]); /// ``` #[inline] pub fn repeat(bit: bool, len: usize) -> Self { let mut out = Self::with_capacity(len); unsafe { out.set_len(len); } out.set_elements(if bit { T::Mem::ALL } else { T::Mem::ZERO }); out } /// Clones a `&BitSlice` into a `BitVec`. /// /// # Original /// /// [`<Vec<T: Clone> as Clone>::clone`](https://doc.rust-lang.org/alloc/vec/struct.Vec.html#impl-Clone) /// /// # Effects /// /// This performs a direct element-wise copy from the source slice to the /// newly-allocated buffer, then sets the vector to have the same starting /// bit as the slice did. This allows for faster behavior. If you require /// that the vector start at the leading edge of the first element, use /// [`force_align`] to guarantee this. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let bits = bits![0, 1, 0, 1, 1, 0, 1, 1]; /// let bv = BitVec::from_bitslice(&bits[2 ..]); /// assert_eq!(bv, bits[2 ..]); /// ``` /// /// [`force_align`]: #method.force_align #[inline] pub fn from_bitslice(slice: &BitSlice<O, T>) -> Self { let mut bitptr = slice.bitptr(); let (base, elts) = (bitptr.pointer().to_const(), bitptr.elements()); let source = unsafe { slice::from_raw_parts(base, elts) }; let vec = elts .pipe(Vec::with_capacity) .pipe(ManuallyDrop::new) .tap_mut(|v| v.extend(source.iter().map(BitStore::load_value))); unsafe { bitptr.set_pointer(vec.as_ptr() as *const T); } let capacity = vec.capacity(); Self { pointer: bitptr.to_nonnull(), capacity, } } /// Converts a `Vec<T>` into a `BitVec<O, T>` without copying its buffer. /// /// # Parameters /// /// - `vec`: A vector to view as bits. /// /// # Returns /// /// A `BitVec` over the `vec` buffer. /// /// # Panics /// /// This panics if `vec` is too long to convert into a `BitVec`. See /// [`BitSlice::MAX_ELTS`]. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let vec = vec![0u8; 4]; /// let bv = BitVec::<LocalBits, _>::from_vec(vec); /// assert_eq!(bv, bits![0; 32]); /// ``` /// /// [`BitSlice::MAX_ELTS`]: /// ../slice/struct.BitSlice.html#associatedconstant.MAX_ELTS #[inline] pub fn from_vec(vec: Vec<T>) -> Self { Self::try_from_vec(vec) .expect("Vector was too long to be converted into a `BitVec`") } /// Converts a `Vec<T>` into a `BitVec<O, T>` without copying its buffer. /// /// This method takes ownership of a memory buffer and enables it to be used /// as a bit-vector. Because `Vec` can be longer than `BitVec`s, this is a /// fallible method, and the original vector will be returned if it cannot /// be converted. /// /// # Parameters /// /// - `vec`: Some vector of memory, to be viewed as bits. /// /// # Returns /// /// If `vec` is short enough to be viewed as a `BitVec`, then this returns /// a `BitVec` over the `vec` buffer. If `vec` is too long, then this /// returns `vec` unmodified. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let vec = vec![0u8; 4]; /// let bv = BitVec::<LocalBits, _>::try_from_vec(vec).unwrap(); /// assert_eq!(bv, bits![0; 32]); /// ``` /// /// An example showing this function failing would require an allocation /// exceeding `!0usize >> 3` bytes in size, which is infeasible to produce. #[inline] pub fn try_from_vec(vec: Vec<T>) -> Result<Self, Vec<T>> { let len = vec.len(); if len > BitSlice::<O, T>::MAX_ELTS { return Err(vec); } let vec = ManuallyDrop::new(vec); let (base, capacity) = (vec.as_ptr(), vec.capacity()); Ok(Self { pointer: unsafe { BitPtr::new_unchecked( base, BitIdx::ZERO, len * T::Mem::BITS as usize, ) } .to_nonnull(), capacity, }) } /// Copies all bits in a `BitSlice` into the `BitVec`. /// /// This is provided for API completeness; it has no performance benefits /// compared to use of the [`Extend`] implementation. /// /// # Parameters /// /// - `&mut self` /// - `other`: A `BitSlice` reference of the same type parameters as `self`. /// /// # Behavior /// /// `self` is extended by the length of `other`, and then the contents of /// `other` are copied into the newly-allocated end of `self`. /// /// ```rust /// use bitvec::prelude::*; /// /// let mut bv = bitvec![0, 1]; /// bv.extend_from_bitslice(bits![1, 1, 0, 1]); /// /// assert_eq!(bv, bits![0, 1, 1, 1, 0, 1]); /// ``` /// /// [`Extend`]: #impl-Extend<%26'a bool> /// [`.as_bitslice()`]: #method.as_bitslice() #[inline] pub fn extend_from_bitslice(&mut self, other: &BitSlice<O, T>) { let len = self.len(); let olen = other.len(); self.resize(len + olen, false); unsafe { self.get_unchecked_mut(len ..) }.clone_from_bitslice(other); } /// Converts the vector into [`BitBox<O, T>`]. /// /// Note that this will drop any excess capacity. /// /// # Original /// /// [`Vec::into_boxed_slice`](https://doc.rust-lang.org/alloc/vec/struct.Vec.html#method.into_boxed_slice) /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let mut bv = bitvec![1; 50]; /// let bb: BitBox = bv.into_boxed_bitslice(); /// assert_eq!(bb, bits![1; 50]); /// ``` /// /// [`BitBox<O, T>`]: ../boxed/struct.BitBox.html #[inline] pub fn into_boxed_bitslice(self) -> BitBox<O, T> { let mut bitptr = self.bitptr(); let boxed = self.into_boxed_slice().pipe(ManuallyDrop::new); unsafe { bitptr.set_pointer(boxed.as_ptr()); } unsafe { BitBox::from_raw(bitptr.to_bitslice_ptr_mut::<O>()) } } /// Converts the vector back into an ordinary vector of memory elements. /// /// This does not affect the vector’s buffer, only the handle used to /// control it. /// /// # Parameters /// /// - `self` /// /// # Returns /// /// An ordinary vector containing all of the bit-vector’s memory buffer. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let bv = bitvec![0; 5]; /// let vec = bv.into_vec(); /// assert_eq!(vec, [0]); /// ``` #[inline] pub fn into_vec(self) -> Vec<T> { let mut this = ManuallyDrop::new(self); let buf = this.as_mut_slice(); unsafe { Vec::from_raw_parts( buf.as_mut_ptr() as *mut T, buf.len(), this.capacity, ) } } /// Gets the number of elements `T` that contain live bits of the vector. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let bv = bitvec![LocalBits, u16; 1; 50]; /// assert_eq!(bv.elements(), 4); /// ``` #[inline] pub fn elements(&self) -> usize { self.bitptr().elements() } /// Sets the uninitialized bits of the vector to a fixed value. /// /// This method modifies all bits in the allocated buffer that are outside /// the `self.as_bitslice()` view so that they have a consistent value. This /// can be used to zero the uninitialized memory so that when viewed as a /// raw memory slice, bits outside the live region have a predictable value. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let mut bv = 220u8.view_bits::<Lsb0>().to_bitvec(); /// assert_eq!(bv.as_slice(), &[220u8]); /// bv.truncate(4); /// assert_eq!(bv.count_ones(), 2); /// assert_eq!(bv.as_slice(), &[220u8]); /// /// bv.set_uninitialized(false); /// assert_eq!(bv.as_slice(), &[12u8]); /// /// bv.set_uninitialized(true); /// assert_eq!(bv.as_slice(), &[!3u8]); /// ``` #[inline] pub fn set_uninitialized(&mut self, value: bool) { let head = self.bitptr().head().value() as usize; let tail = head + self.len(); let capa = self.capacity(); let mut bp = self.bitptr(); unsafe { bp.set_head(BitIdx::ZERO); bp.set_len(capa); let bits = bp.to_bitslice_mut::<O>(); bits.get_unchecked_mut(.. head).set_all(value); bits.get_unchecked_mut(tail ..).set_all(value); } } /// Ensures that the live region of the vector’s contents begins at the /// leading edge of the buffer. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let data = 0x3Cu8; /// let bits = data.view_bits::<Msb0>(); /// /// let mut bv = bits[2 .. 6].to_bitvec(); /// assert_eq!(bv, bits[2 .. 6]); /// assert_eq!(bv.as_slice()[0], data); /// /// bv.force_align(); /// assert_eq!(bv, bits[2 .. 6]); /// // It is not specified what happens to bits that are no longer used. /// assert_eq!(bv.as_slice()[0] & 0xF0, 0xF0); /// ``` #[inline] pub fn force_align(&mut self) { let bitptr = self.bitptr(); let head = bitptr.head().value() as usize; if head == 0 { return; } let last = bitptr.len() + head; unsafe { self.pointer = bitptr.tap_mut(|bp| bp.set_head(BitIdx::ZERO)).to_nonnull(); self.copy_within_unchecked(head .. last, 0); } } /// Writes a value into every element that the vector considers live. /// /// This unconditionally writes `element` into each live location in the /// backing buffer, without altering the `BitVec`’s length or capacity. /// /// It is unspecified what effects this has on the allocated but dead /// elements in the buffer. /// /// # Parameters /// /// - `&mut self` /// - `element`: The value which will be written to each live location in /// the vector’s buffer. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let mut bv = bitvec![LocalBits, u8; 0; 10]; /// assert_eq!(bv.as_slice(), [0, 0]); /// bv.set_elements(0xA5); /// assert_eq!(bv.as_slice(), [0xA5, 0xA5]); /// ``` #[inline] pub fn set_elements(&mut self, element: T::Mem) { self.as_mut_slice() .iter_mut() .for_each(|elt| *elt = element.into()); } /// Views the buffer’s contents as a `BitSlice`. /// /// This is equivalent to `&bv[..]`. /// /// # Original /// /// [`Vec::as_slice`](https://doc.rust-lang.org/alloc/vec/struct.Vec.html#method.as_slice) /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let bv = bitvec![0, 1, 1, 0]; /// let bits = bv.as_bitslice(); /// ``` #[inline] #[cfg(not(tarpaulin_include))] pub fn as_bitslice(&self) -> &BitSlice<O, T> { unsafe { &*self.pointer.as_ptr() } } /// Extracts a mutable bit-slice of the entire vector. /// /// Equivalent to `&mut bv[..]`. /// /// # Original /// /// [`Vec::as_mut_slice`](https://doc.rust-lang.org/alloc/vec/struct.Vec.html#method.as_mut_slice) /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let mut bv = bitvec![0, 1, 0, 1]; /// let bits = bv.as_mut_bitslice(); /// bits.set(0, true); /// ``` #[inline] #[cfg(not(tarpaulin_include))] pub fn as_mut_bitslice(&mut self) -> &mut BitSlice<O, T> { unsafe { &mut *self.pointer.as_ptr() } } /// Returns a raw pointer to the vector’s region. /// /// The caller must ensure that the vector outlives the pointer this /// function returns, or else it will end up pointing to garbage. Modifying /// the vector may cause its buffer to be reallocated, which would also make /// any pointers to it invalid. /// /// The caller must also ensure that the memory the pointer /// (non-transitively) points to is never written to (except inside an /// `UnsafeCell`) using this pointer or any pointer derived from it. If you /// need to mutate the contents of the region, use [`as_mut_bitptr`]. /// /// This pointer is an opaque crate-internal type. Its in-memory /// representation is unsafe to modify in any way. The only safe action to /// take with this pointer is to pass it, unchanged, back into a `bitvec` /// API. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let bv = bitvec![0; 20]; /// let ptr = bv.as_bitptr(); /// /// let bits = unsafe { &*ptr }; /// assert_eq!(bv, bits); /// ``` /// /// [`as_mut_bitptr`]: #method.as_mut_bitptr #[inline] #[cfg(not(tarpaulin_include))] pub fn as_bitptr(&self) -> *const BitSlice<O, T> { self.pointer.as_ptr() as *const BitSlice<O, T> } /// Returns an unsafe mutable pointer to the vector’s region. /// /// The caller must ensure that the vector outlives the pointer this /// function returns, or else it will end up pointing to garbage. Modifying /// the vector may cause its buffer to be reallocated, which would also make /// any pointers to it invalid. /// /// This pointer is an opaque crate-internal type. Its in-memory /// representation is unsafe to modify in any way. The only safe action to /// take with this pointer is to pass it, unchanged, back into a `bitvec` /// API. /// /// # Examples /// /// ```rust /// use bitvec::prelude::*; /// /// let mut bv = bitvec![0; 20]; /// let ptr = bv.as_mut_bitptr(); /// /// let bits = unsafe { &mut *ptr }; /// assert_eq!(bv, bits); /// ``` #[inline] #[cfg(not(tarpaulin_include))] pub fn as_mut_bitptr(&mut self) -> *mut BitSlice<O, T> { self.pointer.as_ptr() } #[inline] #[cfg(not(tarpaulin_include))] pub(crate) fn bitptr(&self) -> BitPtr<T> { self.pointer.as_ptr().pipe(BitPtr::from_bitslice_ptr_mut) } /// Permits a function to modify the `Vec<T>` backing storage of a /// `BitVec<_, T>`. /// /// This produces a temporary `Vec<T::Mem>` structure governing the /// `BitVec`’s buffer and allows a function to view it mutably. After the /// callback returns, the `Vec` is written back into `self` and forgotten. /// /// # Type Parameters /// /// - `F`: A function which operates on a mutable borrow of a `Vec<T::Mem>` /// buffer controller. /// - `R`: The return type of the `F` function. /// /// # Parameters /// /// - `&mut self` /// - `func`: A function which receives a mutable borrow of a `Vec<T::Mem>` /// controlling `self`’s buffer. /// /// # Returns /// /// The return value of `func`. `func` is forbidden from borrowing any part /// of the `Vec<T::Mem>` temporary view. fn with_vec<F, R>(&mut self, func: F) -> R where F: FnOnce(&mut ManuallyDrop<Vec<T::Mem>>) -> R { let cap = self.capacity; let mut bitptr = self.bitptr(); let (base, elts) = (bitptr.pointer().to_mut() as *mut T::Mem, bitptr.elements()); let mut vec = unsafe { Vec::from_raw_parts(base, elts, cap) } .pipe(ManuallyDrop::new); let out = func(&mut vec); unsafe { bitptr.set_pointer(vec.as_ptr() as *mut T); } self.pointer = bitptr.to_nonnull(); self.capacity = vec.capacity(); out } } mod api; mod iter; mod ops; mod traits; pub use iter::{ Drain, IntoIter, Splice, }; #[cfg(test)] mod tests;