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// See the COPYRIGHT file at the top-level directory of this distribution. // Licensed under MIT license <LICENSE-MIT or http://opensource.org/licenses/MIT> //! This library provides a `Vec`-like, no reallocation collection named `indexed::Pool`. //! The pool's reference can be obtained from one of its elements. //! It can be used as a memory pool, and library users do not need to store/pass the pool's reference everywhere. //! The elements can be linked to each other using indexes rather than pointers. //! //! # Examples //! //! ``` //! use indexed::{Indexed,Pool}; //! use std::fmt::{self,Display,Formatter}; //! //! // A singly linked list of string. //! struct List( Box<Pool<Node>> ); //! //! struct Node { //! next : u32, //! index : u32, //! text : &'static str, //! } //! //! unsafe impl Indexed for Node { //! fn null() -> usize { !0_u32 as usize } //! unsafe fn get_index( &self ) -> usize { self.index as usize } //! unsafe fn set_index( &mut self, index: usize ) { self.index = index as u32; } //! } //! //! impl List { //! fn new() -> Self { List( Pool::<Node>::new() )} //! //! fn head<'a>( &'a mut self, text: &'static str ) -> &'a mut Node { //! assert_eq!( self.0.new_index(), 0 ); //! self.0.push( Node{ //! next : Node::null() as u32, //! index : 0, // the pool will set the actual index inside its `push()` method. //! text , //! }); //! &mut self.0[0] //! } //! } //! //! impl Node { //! // The method does not need a parameter of `Pool`. //! fn add<'a>( &'a mut self, sib: &'static str ) -> &'a mut Self { //! let pool = unsafe { self.pool_mut() as *mut Pool<Node> }; //! let index = unsafe{ (*pool).new_index() }; //! self.next = index as u32; //! let pool = unsafe{ &mut *pool }; //! pool.push( Node{ //! next : Node::null() as u32, //! index : Node::null() as u32, // the pool will set the actual index inside its `push()` method. //! text : sib, //! }); //! &mut pool[index] //! } //! } //! //! impl Display for List { //! fn fmt( &self, fmt: &mut Formatter ) -> fmt::Result { //! if self.0.new_index() != 0 { //! let mut curr = 0_usize; //! while curr != Node::null() { //! write!( fmt, "{} ", self.0[curr].text )?; //! curr = self.0[curr].next as usize; //! } //! } //! Ok(()) //! } //! } //! //! let mut list = List::new(); //! list.head( "no" ).add( "need" ).add( "for" ).add( "pool" ).add( "parameter" ); //! assert_eq!( list.to_string(), "no need for pool parameter " ); //! ``` #![cfg_attr( feature = "no_std", no_std )] #![cfg_attr( feature = "no_std", feature( alloc ))] #[cfg(not(feature="no_std"))] pub(crate) use std::boxed::Box; #[cfg(not(feature="no_std"))] pub(crate) use std::fmt::{self,Debug}; #[cfg(not(feature="no_std"))] pub(crate) use std::marker::PhantomData; #[cfg(not(feature="no_std"))] pub(crate) use std::mem::{self,transmute}; #[cfg(not(feature="no_std"))] pub(crate) use std::ops; #[cfg(not(feature="no_std"))] pub(crate) use std::ptr::{self,NonNull,drop_in_place}; #[cfg(feature="no_std")] extern crate alloc; #[cfg(feature="no_std")] pub(crate) use self::alloc::boxed::Box; #[cfg(feature="no_std")] pub(crate) use self::alloc::vec::Vec; #[cfg(feature="no_std")] pub(crate) use core::fmt::{self,Debug}; #[cfg(feature="no_std")] pub(crate) use core::marker::PhantomData; #[cfg(feature="no_std")] pub(crate) use core::mem::{self,transmute}; #[cfg(feature="no_std")] pub(crate) use core::ops; #[cfg(feature="no_std")] pub(crate) use core::ptr::{self,NonNull,drop_in_place}; /// Possible chunk sizes. pub enum ChunkLen { B5 = 32, B6 = 64, B7 = 128, B8 = 256, B9 = 512, B10 = 1024, B11 = 2048, B12 = 4096, B13 = 8192, B14 = 16384, B15 = 32768, B16 = 65536, } /// Reflects the count of elements a chunk can hold. pub fn chunk_len<T:Indexed>() -> usize { <T as Indexed>::chunk_len() as isize as usize } /// Type of elements in the `Pool` must implement this trait. /// Typically some integer field in the type must devote to storing the index in the pool, and it is not necessarily usize. /// For example, an index can be stored in u32 if 4194304K is enough for anybody. pub unsafe trait Indexed: Sized { /// Sets the underlying chunk size. The default is 256, and can be overrided by those values defined in `ChunkLen`. fn chunk_len() -> ChunkLen { ChunkLen::B8 } /// Defines which index value is for null. If the underlying storage for index is smaller than `usize`'s size, the library user should override this method and pick a smaller value, e.g `!0_u32` for index stored in `u32`. /// Note that it is for convenience only, and the library will not do any index check against `null()`. fn null() -> usize { !0_usize } /// Gets the element's index in the pool. unsafe fn get_index( &self ) -> usize; /// Sets the element's index in the pool. The library user is not expected to call it directly. unsafe fn set_index( &mut self, index: usize ); /// Obtains reference of its pool. fn pool( &self ) -> &Pool<Self> { Pool::pool( self )} /// Obtains mutable reference of its pool. unsafe fn pool_mut( &self ) -> &mut Pool<Self> { Pool::pool_mut( self )} /// Obtains non null pointer of its pool. fn pool_non_null( &self ) -> NonNull<Pool<Self>> { unsafe{ NonNull::new_unchecked( Pool::pool_mut( self ))}} /// Appends an element to the back of its pool. fn pool_push( &self, value: Self ) { unsafe{ self.pool_mut().push( value )}} /// Overwrites a new value into its pool at given index without reading or dropping the old value. unsafe fn pool_write( &self, index: usize, value: Self ) { self.pool_mut().write( index, value ); } /// Reserves capacity for at least additional more elements to be inserted in the given Pool<T>. /// The collection may reserve more space because the increasing size must be multiple of underlying `chunk_len()`. /// After calling reserve, capacity will be greater than or equal to self.pool().new_index() + additional. /// Does nothing if capacity is already sufficient. fn pool_reserve( &self, additional: usize ) { unsafe{ self.pool_mut().reserve( additional ); }} } #[derive(PartialEq,Eq)] struct Chunk<T>( Vec<u8>, PhantomData<T> ); type PPool<T> = NonNull<Pool<T>>; impl<T:Indexed> Chunk<T> { #[inline] fn data_size() -> usize { mem::size_of::<[T;1]>() * chunk_len::<T>() } #[inline] fn buffer_size() -> usize { Self::data_size() + mem::size_of::<PPool<T>>() } #[inline] fn as_ptr( &self ) -> *const T { self.0.as_ptr() as *const T } #[inline] fn as_mut_ptr( &mut self ) -> *mut T { self.0.as_mut_ptr() as *mut T } #[inline] fn data_ptr( &self, index: usize ) -> *const T { unsafe{( self.as_ptr() ).add( index )}} #[inline] fn data_mut_ptr( &mut self, index: usize ) -> *mut T { unsafe{( self.as_mut_ptr() ).add( index )}} #[inline] fn ppool( &self ) -> *const PPool<T> { self.data_ptr( chunk_len::<T>() ) as *const PPool<T> } #[inline] fn new( ppool: PPool<T> ) -> Self { let mut buffer = Vec::<u8>::with_capacity( Self::buffer_size() ); unsafe { ptr::write( buffer.as_mut_ptr().add( Self::data_size() ) as *mut NonNull<_>, ppool ); } Chunk( buffer, PhantomData ) } #[inline] fn write( &mut self, index: usize, value: T ) { assert!( index <= chunk_len::<T>() ); unsafe{ ptr::write( self.data_mut_ptr( index ), value )}; } } impl<T:Indexed+Debug> Debug for Chunk<T> { fn fmt( &self, fmt: &mut fmt::Formatter ) -> fmt::Result { let mut p = self.as_ptr(); let mut count = chunk_len::<T>(); let mut buffer = Vec::with_capacity( count ); while count > 0 { buffer.push( unsafe{ ptr::read( p )}); unsafe{ p = p.offset(1) }; count -= 1; } fmt.write_str( "\n" )?; fmt.debug_struct( "Chunk" ) .field( "ppool", unsafe{ &ptr::read( self.ppool() )}) .field( "buffer", &buffer ) .finish()?; unsafe{ buffer.set_len(0); } Ok(()) } } impl<T:Indexed> ops::Index<usize> for Chunk<T> { type Output = T; fn index( &self, index: usize ) -> &T { unsafe{ &*self.data_ptr( index )}} } impl<T:Indexed> ops::IndexMut<usize> for Chunk<T> { fn index_mut( &mut self, index: usize ) -> &mut T { unsafe{ &mut *self.data_mut_ptr( index )}} } /// A `Vec`-like, no reallocation collection. /// Elements in a `Pool` should not be zero sized type, or the construction will panic. #[derive(Debug,PartialEq,Eq)] pub struct Pool<T:Indexed> { chunks : Vec<Chunk<T>>, // underlying storage. managed : bool, // whether drops elements on destruction or not. ppool : PPool<T>, // NonNull pointer to self. subidx : usize, // index of last element in its chunk, or `chunk_len::<T>()-1` if no element in the pool at all. len : usize, // element count of the pool. cap : usize, // capacity of the pool, always multiple of `chunk_len::<T>()`. } impl<T:Indexed> Pool<T> { /// Creates a new pool that drops its elements on destruction. /// /// # Panics /// /// Panics if the type of element is ZST. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// static mut COUNT: usize = 0; /// /// struct Name { index: usize, text: String } /// /// impl_indexed!{ Name{ index: usize }} /// /// impl Drop for Name { fn drop( &mut self ) { unsafe{ COUNT += 1; }}} /// /// impl From<&'static str> for Name { /// fn from( s: &'static str ) -> Self { /// Name{ index: <Self as Indexed>::null(), text: s.to_string() } /// } /// } /// /// { let pool = pool!( Name[ "foo", "bar", "baz" ]); } /// /// assert_eq!( unsafe{ COUNT }, 3 ); /// ``` pub fn new() -> Box<Self> { Self::new_pool( true )} /// Creates a new pool that does not drop its elements on destruction. /// It is up to the user to drop the elements manually to avoid memory leaks. /// /// # Panics /// /// Panics if the type of element is ZST. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// static mut COUNT: usize = 0; /// /// struct Name { index: usize, text: String } /// /// impl_indexed!{ Name{ index: usize }} /// /// impl Drop for Name { fn drop( &mut self ) { unsafe{ COUNT += 1; }}} /// /// impl From<&'static str> for Name { /// fn from( s: &'static str ) -> Self { /// Name{ index: <Self as Indexed>::null(), text: s.to_string() } /// } /// } /// /// { /// let mut pool = Pool::<Name>::new_unmanaged(); /// pool.push( "foo".into() ); /// pool.push( "bar".into() ); /// pool.push( "baz".into() ); /// } /// assert_eq!( unsafe{ COUNT }, 0 ); /// ``` pub fn new_unmanaged() -> Box<Self> { Self::new_pool( false )} fn new_pool( managed: bool ) -> Box<Self> { if mem::size_of::<T>() == 0 { panic!( "ZSTs are not allowed to be the `Pool`'s element type." ); } else { let pool = Box::new( Self { chunks : Vec::new(), managed , ppool : NonNull::dangling(), subidx : chunk_len::<T>()-1, len : 0, cap : 0, }); unsafe { let pool = Box::into_raw( pool ); let ppool = NonNull::new_unchecked( pool ); let mut pool = Box::from_raw( pool ); pool.ppool = ppool; pool } } } /// Appends an element to the back of a pool. /// /// # Panics /// /// Panics if the number of elements in the vector overflows a `usize`. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: i32 }} /// /// let mut pool = Pool::new(); /// /// pool.push( Foo::from( 0 )); /// pool.push( Foo::from( 1 )); /// pool.push( Foo::from( 2 )); /// /// assert_eq!( pool.iter().map( |e| e.inner ).collect::<Vec<_>>(), vec![ 0, 1, 2 ]); /// ``` pub fn push( &mut self, mut value: T ) { self.subidx += 1; let chunk_len = chunk_len::<T>(); if self.subidx == chunk_len { if self.len == Self::check( self.chunks.len(), usize::checked_mul, chunk_len ) { self.chunks.push( Chunk::new( self.ppool )); self.cap += chunk_len; } self.subidx = 0; } let len = self.len; unsafe{ value.set_index( len )}; self.chunks.last_mut().unwrap().write( self.subidx, value ); self.len += 1; } /// Overwrites a new value into a pool at given index without reading or dropping the old value. /// /// # Safety /// /// This operation is marked unsafe because it accepts an index as an offset which acts like a raw pointer. /// /// It does not drop the contents of the existing `self[index]` element. This is safe, but it could leak allocations or resources, /// so care must be taken not to overwrite an object that should be dropped. /// /// Additionally, it does not drop `value`. Semantically, `value` is moved into `self[index]`. /// /// This is appropriate for initializing uninitialized memory. /// /// # Examples /// /// Basic usage: /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: &'static str }} /// /// let mut pool = Pool::<Foo>::new(); /// /// pool.reserve( 3 ); /// /// unsafe { /// pool.write( 0, "a".into() ); /// pool.write( 2, "c".into() ); /// pool.write( 1, "b".into() ); /// pool.set_len( 3 ); /// } /// /// assert_eq!( pool.iter().map( |e| e.inner ).collect::<Vec<_>>(), vec![ "a", "b", "c" ]); /// ``` #[inline] pub unsafe fn write( &mut self, index: usize, mut value: T ) { value.set_index( index ); self.chunks[ index / chunk_len::<T>() ].write( index % chunk_len::<T>(), value ); } /// Reserves capacity for at least additional more elements to be inserted in the given Pool<T>. /// The collection may reserve more space because the increasing size must be multiple of underlying `chunk_len()`. /// After calling reserve, capacity will be greater than or equal to self.new_index() + additional. /// Does nothing if capacity is already sufficient. /// /// # Panics /// /// Panics if the new capacity overflows `usize`. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: &'static str }} /// /// let mut pool = Pool::<Foo>::new(); /// /// pool.reserve( 0 ); /// assert_eq!( pool.capacity(), 0 ); /// /// pool.reserve( 1 ); /// let cap = pool.capacity(); /// assert!( cap >= 1 ); /// /// pool.reserve( 1 ); /// assert_eq!( pool.capacity(), cap ); /// /// pool.reserve( 1024 ); /// assert!( pool.capacity() >= 1024 ); /// ``` pub fn reserve( &mut self, additional: usize ) { if let Some( inc_cap ) = self.check_len( usize::checked_add, additional ) // self.len + additional .checked_sub( self.cap ) // - self.cap { let mut chunk_count = inc_cap / chunk_len::<T>(); if inc_cap > 0 && chunk_count == 0 { chunk_count = 1; } for _ in 0..chunk_count { self.chunks.push( Chunk::new( self.ppool )); } self.cap += inc_cap; } } /// Returns the number of elements in the pool, also referred to as its 'length'. #[inline] /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: &'static str }} /// /// let mut pool = pool!( Foo[ "a", "b", "c" ]); /// assert_eq!( pool.len(), 3 ); /// ``` #[inline] pub fn len( &self ) -> usize { self.len } /// Sets the length of a pool. /// /// This will explicitly set the size of the pool, without actually modifying its buffers, /// so it is up to the caller to ensure that the pool is actually the specified size. /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: char }} /// /// let mut pool = pool!( Foo[ 'r', 'u', 's', 't' ]); /// /// unsafe { /// std::ptr::drop_in_place( &mut pool[3] ); /// pool.set_len( 3 ); /// } /// /// assert_eq!( pool.len(), 3 ); /// assert_eq!( pool.iter().map( |e| e.inner ).collect::<Vec<_>>(), vec!['r', 'u', 's'] ); /// ``` /// /// In this example, there is a memory leak since the memory locations /// owned by the first `Name` were not freed prior to the `set_len` call: /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// static mut COUNT: usize = 0; /// /// struct Name { index: usize, text: String } /// /// impl_indexed!{ Name{ index: usize }} /// /// impl Drop for Name { fn drop( &mut self ) { unsafe{ COUNT += 1; }}} /// /// impl From<&'static str> for Name { /// fn from( s: &'static str ) -> Self { /// Name{ index: <Self as Indexed>::null(), text: s.to_string() } /// } /// } /// /// let mut pool = pool!( Name[ "abc", "def", "g" ]); /// /// unsafe { /// std::ptr::drop_in_place( &mut pool[2] ); /// std::ptr::drop_in_place( &mut pool[1] ); /// pool.set_len( 0 ); /// } /// /// assert_eq!( unsafe{ COUNT }, 2 ); /// ``` /// In this example, the pool gets expanded from zero to four items without any memory allocations occurring, /// resulting in pool values of unallocated memory: /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: &'static str }} /// /// let mut pool = Pool::<Foo>::new(); /// unsafe { pool.set_len( 3 ); } /// ``` #[inline] pub unsafe fn set_len( &mut self, len: usize ) { self.len = len; let sublen = len % chunk_len::<T>(); self.subidx = if sublen == 0 { chunk_len::<T>()-1 } else { sublen-1 }; } /// Returns the number of elements the vector can hold without more allocating. /// /// Note: **the purpose of this method is not to avoid reallocation**, which could not happen at all, but to grow the buffer for next incomming `write()`s. #[inline] pub fn capacity( &self ) -> usize { self.cap } /// Returns the pool's `NonNull` pointer. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: i32 }} /// /// let mut pool = Pool::<Foo>::new(); /// let p = pool.non_null(); /// /// assert_eq!( p, std::ptr::NonNull::new( Box::into_raw( pool )).unwrap() ); /// ``` pub fn non_null( &self ) -> NonNull<Self> { self.ppool } /// Obtains reference of the pool of an element. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: usize }} /// /// let mut pool = Pool::<Foo>::new(); /// /// for i in 0..1024 { /// pool.push( i.into() ); /// } /// /// for i in 0..1024 { /// assert!( pool.non_null().as_ptr() as *const Pool<Foo> == pool[i].pool() ); /// } /// ``` pub fn pool( value: &T ) -> &Self { unsafe { let remainder = value.get_index() % chunk_len::<T>(); let value = value as *const T; let off = ( chunk_len::<T>() - remainder ) as isize; let ppool = ptr::read( value.offset( off ) as *const PPool<T> ); &*ppool.as_ptr() } } /// Obtains mutable reference of the pool from an element. /// /// # Safety /// /// This operation is marked unsafe because it obtains a mutable reference of the `Pool` from one of its immutable element, /// which may violate the memory safety rule "only one mutable reference, or none but multiple immutable references". /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: usize }} /// /// let mut pool = Pool::<Foo>::new(); /// /// for i in 0..1024 { /// pool.push( i.into() ); /// } /// /// for i in 0..1024 { /// assert_eq!( pool.non_null().as_ptr(), /// unsafe{ pool[i].pool_mut() as *mut Pool<Foo>}); /// } /// ``` pub unsafe fn pool_mut( value: &T ) -> &mut Self { let remainder = value.get_index() % chunk_len::<T>(); let value = value as *const T; let off = ( chunk_len::<T>() - remainder ) as isize; let ppool = ptr::read( value.offset( off ) as *const PPool<T> ); &mut *ppool.as_ptr() } /// Obtains `NonNull` pointer of the pool from an element. pub fn pool_non_null( value: &T ) -> NonNull<Self> { unsafe{ NonNull::new_unchecked( Self::pool_mut( value ))}} /// Returns the expected index for the next new element to be `push()`ed in. pub fn new_index( &self ) -> usize { self.len } /// Returns `true` if the pool contains no elements. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: &'static str }} /// /// let mut pool = Pool::new(); /// assert!( pool.is_empty() ); /// /// pool.push( Foo::from( "foo" )); /// assert!( !pool.is_empty() ); /// ``` pub fn is_empty( &self ) -> bool { self.len == 0 } /// Returns an iterator over the pool. /// /// # Examples /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: &'static str }} /// /// let mut pool = pool!( Foo[ "abc", "def", "g" ]); /// let mut iter = pool.iter(); /// /// assert_eq!( iter.next().unwrap().inner, "abc" ); /// assert_eq!( iter.next().unwrap().inner, "def" ); /// assert_eq!( iter.next().unwrap().inner, "g" ); /// assert!( iter.next().is_none() ); /// ``` #[inline] pub fn iter( &self ) -> Iter<T> { let last = if self.chunks.is_empty() {(0,0)} else {( self.chunks.len()-1, self.subidx )}; Iter{ pool: self, chunk_idx: 0, elem_idx: 0, last } } /// Returns an iterator that allows modifying each value. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: i32 }} /// /// let mut pool = pool!( Foo[ 0, 1, 2 ]); /// /// pool.iter_mut().for_each( |elem| { elem.inner += 10; }); /// /// assert_eq!( pool.iter().map( |e| e.inner ).collect::<Vec<_>>(), vec![ 10, 11, 12 ]); /// ``` pub fn iter_mut( &mut self ) -> IterMut<T> { let last = if self.chunks.is_empty() {(0,0)} else {( self.chunks.len()-1, self.subidx )}; IterMut{ pool: self, chunk_idx: 0, elem_idx: 0, last } } /// Returns a shared reference to the output at indexed location, without performing any bounds checking. pub unsafe fn get_unchecked( &self, index: usize ) -> &T { &self.chunks.get_unchecked( index / chunk_len::<T>() )[ index % chunk_len::<T>() ] } /// Returns a mutable reference to the output at indexed location, without performing any bounds checking. pub unsafe fn get_unchecked_mut( &mut self, index: usize ) -> &mut T { &mut self.chunks.get_unchecked_mut( index / chunk_len::<T>() )[ index % chunk_len::<T>() ] } fn check( len: usize, grow: fn(usize,usize) -> Option<usize>, additional: usize ) -> usize { let len = grow( len, additional ).expect( "the requested capacity should be less or equal to `usize::MAX`" ); if mem::size_of::<usize>() < 8 && len > !0_isize as usize { panic!( "the requested capacity on 32/16 bit platform should be less or equal to `isize::MAX`" ); } len } fn check_len( &self, grow: fn(usize,usize) -> Option<usize>, additional: usize ) -> usize { Self::check( self.len, grow, additional )} } impl<T:Indexed> Drop for Pool<T> { fn drop( &mut self ) { let len = self.chunks.len(); if self.managed && len > 0 { unsafe{ self.chunks.set_len( 0 ); } for i in 0..len-1 { for j in 0..chunk_len::<T>() { unsafe{ drop_in_place( &mut self.chunks.get_unchecked_mut(i)[j] ); } } } unsafe { let last = self.chunks.get_unchecked_mut( len-1 ); for j in 0..=self.subidx { drop_in_place( &mut last[ j ]); } } } } } impl<T:Indexed> ops::Index<usize> for Pool<T> { type Output = T; fn index( &self, index: usize ) -> &T { &self.chunks[ index / chunk_len::<T>() ][ index % chunk_len::<T>() ] } } impl<T:Indexed> ops::IndexMut<usize> for Pool<T> { fn index_mut( &mut self, index: usize ) -> &mut T { &mut self.chunks[ index / chunk_len::<T>() ][ index % chunk_len::<T>() ] } } /// Immutable pool iterator /// /// This struct is created by the `iter` method. pub struct Iter<'a, T:'a+Indexed> { pool : &'a Pool<T>, chunk_idx : usize, elem_idx : usize, last : ( usize, usize ), } impl<'a, T:'a+Indexed> Iterator for Iter<'a,T> { type Item = &'a T; fn next( &mut self ) -> Option<&'a T> { if ( self.chunk_idx, self.elem_idx ) <= self.last { let chunk = unsafe{ self.pool.chunks.get_unchecked( self.chunk_idx )}; let elem = &chunk[ self.elem_idx ]; if self.elem_idx == chunk_len::<T>() { self.elem_idx = 0; self.chunk_idx += 1; } else { self.elem_idx += 1; } Some( elem ) } else { None } } } /// Mutable pool iterator /// /// This struct is created by the `iter_mut` method. pub struct IterMut<'a, T:'a+Indexed> { pool : &'a mut Pool<T>, chunk_idx : usize, elem_idx : usize, last : ( usize, usize ), } impl<'a, T:'a+Indexed> Iterator for IterMut<'a,T> { type Item = &'a mut T; fn next( &mut self ) -> Option<&'a mut T> { if ( self.chunk_idx, self.elem_idx ) <= self.last { let chunk = unsafe{ self.pool.chunks.get_unchecked_mut( self.chunk_idx )}; let elem = &mut chunk[ self.elem_idx ]; if self.elem_idx == chunk_len::<T>() { self.elem_idx = 0; self.chunk_idx += 1; } else { self.elem_idx += 1; } Some( unsafe{ transmute( elem )}) } else { None } } } /// Creates a `Pool` containing the arguments. The element type of the pool must be given explicitly inside the macro, of which the arguments is able to be converted `into`. /// /// The wrapped data can be accessed via `inner` field. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: &'static str }} /// /// let mut pool = pool!( Foo[ "a", "b", "c" ]); /// /// assert_eq!( pool[0].inner, "a" ); /// assert_eq!( pool[1].inner, "b" ); /// assert_eq!( pool[2].inner, "c" ); /// ``` #[macro_export] macro_rules! pool { ( $ty:ty[ $($x:expr),* ] ) => {{ let mut pool = $crate::Pool::<$ty>::new(); $( pool.push( $x.into() ); )* pool }}; ( $ty:ty[ $($x:expr,)* ] ) => { pool!( $ty[ $($x),* ])}; } /// Implements `Indexed` for a given type, using a given field as index storage of a given type which can be converted from/to `usize` using `as`. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// struct Name { id: u32, text: String }; /// /// impl_indexed!{ Name{ id: u32 }} /// /// let mut _pool = Pool::<Name>::new(); /// ``` #[macro_export] macro_rules! impl_indexed { ( $name:ident { $field:ident:$field_ty:ty } ) => { unsafe impl Indexed for $name { unsafe fn get_index( &self ) -> usize { self.$field as usize } unsafe fn set_index( &mut self, index: usize ) { self.$field = index as $field_ty; } } }; } /// Defines a wrapper type of a given type and implements `Indexed` for the wrapper. /// /// The wrapped data can be accessed via `inner` field. /// /// # Examples /// /// ``` /// #[macro_use] extern crate indexed; /// use indexed::{Indexed,Pool}; /// /// extrusive_indexed!{ Foo{ inner: i32 }} /// /// let mut pool = pool!( Foo[ /// Foo::from( 0 ), /// Foo::from( 1 ), /// Foo::from( 2 ), /// ]); /// /// pool.iter_mut().for_each( |foo| foo.inner += 10 ); /// assert_eq!( pool.iter().map( |e| e.inner ).collect::<Vec<_>>(), vec![ 10, 11, 12 ]); /// ``` #[macro_export] macro_rules! extrusive_indexed { ($vis:vis $outer:ident { inner: $inner:ty }) => { $vis struct $outer { index: usize, pub inner: $inner } unsafe impl Indexed for $outer { unsafe fn get_index( &self ) -> usize { self.index } unsafe fn set_index( &mut self, index: usize ) { self.index = index; } } impl From<$inner> for $outer { fn from( inner: $inner ) -> Self { $outer{ index: <Self as Indexed>::null(), inner }} } }; } #[cfg(test)] mod tests { use super::*; #[test] fn it_works() { unsafe impl Indexed for (usize,usize) { unsafe fn get_index( &self ) -> usize { self.0 } unsafe fn set_index( &mut self, index: usize ) { self.0 = index; } } let pool: Box<Pool<(usize,usize)>> = Pool::new(); let addr: *mut Pool<_> = Box::into_raw( pool ); let mut pool: Box<Pool<(usize,usize)>> = unsafe{ Box::from_raw( addr )}; let mut ptrs = Vec::new(); let ( a, b ) = ( 256_usize, 1024 ); for i in 0..a { pool.push( (0,i) ); ptrs.push( &pool[i] as *const _ ); } for i in a..b { pool.push( (0,i) ); } for i in 0..a { assert_eq!( ptrs[i], &pool[i] as *const _ ); assert_eq!( pool[i].pool() as *const _, addr ); } for i in a..b { assert_eq!( pool[i].pool() as *const _, addr ); } } #[test] #[should_panic( expected = "ZSTs are not allowed to be the `Pool`'s element type." )] fn test_zst() { struct S; unsafe impl Indexed for S { unsafe fn get_index( &self ) -> usize { !0 } unsafe fn set_index( &mut self, _index: usize ) {} } let _pool = Pool::<S>::new(); } }