1132 lines
34 KiB
Rust
1132 lines
34 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// This is an attempt at an implementation following the ideal
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//
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// ```
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// struct BTreeMap<K, V> {
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// height: usize,
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// root: Option<Box<Node<K, V, height>>>
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// }
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//
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// struct Node<K, V, height: usize> {
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// keys: [K; 2 * B - 1],
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// vals: [V; 2 * B - 1],
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// edges: if height > 0 {
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// [Box<Node<K, V, height - 1>>; 2 * B]
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// } else { () },
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// parent: *const Node<K, V, height + 1>,
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// parent_idx: u16,
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// len: u16,
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// }
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// ```
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//
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// Since Rust doesn't acutally have dependent types and polymorphic recursion,
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// we make do with lots of unsafety.
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use alloc::heap;
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use core::marker::PhantomData;
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use core::mem;
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use core::nonzero::NonZero;
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use core::ptr::{self, Unique};
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use core::slice;
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use boxed::Box;
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const B: usize = 6;
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pub const CAPACITY: usize = 2 * B - 1;
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struct LeafNode<K, V> {
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keys: [K; CAPACITY],
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vals: [V; CAPACITY],
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parent: *const InternalNode<K, V>,
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parent_idx: u16,
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len: u16,
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}
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impl<K, V> LeafNode<K, V> {
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unsafe fn new() -> Self {
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LeafNode {
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keys: mem::uninitialized(),
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vals: mem::uninitialized(),
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parent: ptr::null(),
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parent_idx: mem::uninitialized(),
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len: 0
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}
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}
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}
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// We use repr(C) so that a pointer to an internal node can be
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// directly used as a pointer to a leaf node
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#[repr(C)]
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struct InternalNode<K, V> {
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data: LeafNode<K, V>,
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edges: [BoxedNode<K, V>; 2 * B],
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}
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impl<K, V> InternalNode<K, V> {
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unsafe fn new() -> Self {
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InternalNode {
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data: LeafNode::new(),
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edges: mem::uninitialized()
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}
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}
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}
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struct BoxedNode<K, V> {
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ptr: Unique<LeafNode<K, V>> // we don't know if this points to a leaf node or an internal node
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}
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impl<K, V> BoxedNode<K, V> {
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fn from_leaf(node: Box<LeafNode<K, V>>) -> Self {
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unsafe {
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BoxedNode { ptr: Unique::new(Box::into_raw(node)) }
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}
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}
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fn from_internal(node: Box<InternalNode<K, V>>) -> Self {
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unsafe {
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BoxedNode { ptr: Unique::new(Box::into_raw(node) as *mut LeafNode<K, V>) }
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}
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}
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unsafe fn from_ptr(ptr: NonZero<*const LeafNode<K, V>>) -> Self {
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BoxedNode { ptr: Unique::new(*ptr as *mut LeafNode<K, V>) }
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}
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fn as_ptr(&self) -> NonZero<*const LeafNode<K, V>> {
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unsafe {
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NonZero::new(*self.ptr as *const LeafNode<K, V>)
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}
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}
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}
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/// An owned tree. Note that despite being owned, this does not have a destructor,
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/// and must be cleaned up manually.
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pub struct Root<K, V> {
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node: BoxedNode<K, V>,
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height: usize
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}
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unsafe impl<K: Sync, V: Sync> Sync for Root<K, V> { }
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unsafe impl<K: Send, V: Send> Send for Root<K, V> { }
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impl<K, V> Root<K, V> {
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pub fn new_leaf() -> Self {
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Root {
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node: BoxedNode::from_leaf(Box::new(unsafe { LeafNode::new() })),
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height: 0
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}
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}
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pub fn as_ref(&self)
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-> NodeRef<marker::Immut, K, V, marker::LeafOrInternal> {
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NodeRef {
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height: self.height,
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node: self.node.as_ptr(),
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root: self as *const _ as *mut _,
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_marker: PhantomData,
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}
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}
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pub fn as_mut(&mut self)
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-> NodeRef<marker::Mut, K, V, marker::LeafOrInternal> {
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NodeRef {
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height: self.height,
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node: self.node.as_ptr(),
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root: self as *mut _,
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_marker: PhantomData,
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}
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}
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pub fn into_ref(self)
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-> NodeRef<marker::Owned, K, V, marker::LeafOrInternal> {
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NodeRef {
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height: self.height,
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node: self.node.as_ptr(),
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root: ptr::null_mut(), // FIXME: Is there anything better to do here?
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_marker: PhantomData,
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}
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}
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/// Add a new internal node with a single edge, pointing to the previous root, and make that
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/// new node the root. This increases the height by 1 and is the opposite of `pop_level`.
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pub fn push_level(&mut self)
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-> NodeRef<marker::Mut, K, V, marker::Internal> {
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let mut new_node = Box::new(unsafe { InternalNode::new() });
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new_node.edges[0] = unsafe { BoxedNode::from_ptr(self.node.as_ptr()) };
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self.node = BoxedNode::from_internal(new_node);
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self.height += 1;
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let mut ret = NodeRef {
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height: self.height,
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node: self.node.as_ptr(),
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root: self as *mut _,
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_marker: PhantomData
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};
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unsafe {
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ret.reborrow_mut().first_edge().correct_parent_link();
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}
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ret
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}
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/// Remove the root node, using its first child as the new root. This cannot be called when
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/// the tree consists only of a leaf node. As it is intended only to be called when the root
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/// has only one edge, no cleanup is done on any of the other children are elements of the root.
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/// This decreases the height by 1 and is the opposite of `push_level`.
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pub fn pop_level(&mut self) {
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debug_assert!(self.height > 0);
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let top = *self.node.ptr as *mut u8;
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self.node = unsafe {
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BoxedNode::from_ptr(self.as_mut()
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.cast_unchecked::<marker::Internal>()
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.first_edge()
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.descend()
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.node)
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};
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self.height -= 1;
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self.as_mut().as_leaf_mut().parent = ptr::null();
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unsafe {
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heap::deallocate(
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top,
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mem::size_of::<InternalNode<K, V>>(),
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mem::align_of::<InternalNode<K, V>>()
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);
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}
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}
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}
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// N.B. `NodeRef` is always covariant in `K` and `V`, even when the `BorrowType`
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// is `Mut`. This is technically wrong, but cannot result in any unsafety due to
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// internal use of `NodeRef` because we stay completely generic over `K` and `V`.
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// However, whenever a public type wraps `NodeRef`, make sure that it has the
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// correct variance.
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/// A reference to a node.
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///
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/// This type has a number of paramaters that controls how it acts:
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/// - `BorrowType`: This can be `Immut<'a>` or `Mut<'a>` for some `'a` or `Owned`.
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/// When this is `Immut<'a>`, the `NodeRef` acts roughly like `&'a Node`,
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/// when this is `Mut<'a>`, the `NodeRef` acts roughly like `&'a mut Node`,
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/// and when this is `Owned`, the `NodeRef` acts roughly like `Box<Node>`.
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/// - `K` and `V`: These control what types of things are stored in the nodes.
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/// - `Type`: This can be `Leaf`, `Internal`, or `LeafOrInternal`. When this is
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/// `Leaf`, the `NodeRef` points to a leaf node, when this is `Internal` the
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/// `NodeRef` points to an internal node, and when this is `LeafOrInternal` the
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/// `NodeRef` could be pointing to either type of node.
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pub struct NodeRef<BorrowType, K, V, Type> {
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height: usize,
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node: NonZero<*const LeafNode<K, V>>,
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root: *const Root<K, V>,
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_marker: PhantomData<(BorrowType, Type)>
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}
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impl<'a, K: 'a, V: 'a, Type> Copy for NodeRef<marker::Immut<'a>, K, V, Type> { }
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impl<'a, K: 'a, V: 'a, Type> Clone for NodeRef<marker::Immut<'a>, K, V, Type> {
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fn clone(&self) -> Self {
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*self
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}
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}
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unsafe impl<BorrowType, K: Sync, V: Sync, Type> Sync
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for NodeRef<BorrowType, K, V, Type> { }
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unsafe impl<'a, K: Sync + 'a, V: Sync + 'a, Type> Send
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for NodeRef<marker::Immut<'a>, K, V, Type> { }
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unsafe impl<'a, K: Send + 'a, V: Send + 'a, Type> Send
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for NodeRef<marker::Mut<'a>, K, V, Type> { }
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unsafe impl<K: Send, V: Send, Type> Send
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for NodeRef<marker::Owned, K, V, Type> { }
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impl<BorrowType, K, V> NodeRef<BorrowType, K, V, marker::Internal> {
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fn as_internal(&self) -> &InternalNode<K, V> {
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unsafe {
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&*(*self.node as *const InternalNode<K, V>)
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}
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}
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}
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impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
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fn as_internal_mut(&mut self) -> &mut InternalNode<K, V> {
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unsafe {
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&mut *(*self.node as *mut InternalNode<K, V>)
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}
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}
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}
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impl<BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> {
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pub fn len(&self) -> usize {
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self.as_leaf().len as usize
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}
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pub fn forget_type(self) -> NodeRef<BorrowType, K, V, marker::LeafOrInternal> {
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NodeRef {
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height: self.height,
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node: self.node,
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root: self.root,
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_marker: PhantomData
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}
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}
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fn reborrow<'a>(&'a self) -> NodeRef<marker::Immut<'a>, K, V, Type> {
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NodeRef {
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height: self.height,
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node: self.node,
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root: self.root,
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_marker: PhantomData
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}
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}
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fn as_leaf(&self) -> &LeafNode<K, V> {
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unsafe {
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&**self.node
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}
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}
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pub fn keys(&self) -> &[K] {
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self.reborrow().into_slices().0
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}
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pub fn vals(&self) -> &[V] {
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self.reborrow().into_slices().1
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}
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pub fn ascend(self) -> Result<
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Handle<
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NodeRef<
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BorrowType,
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K, V,
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marker::Internal
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>,
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marker::Edge
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>,
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||
Self
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> {
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if self.as_leaf().parent.is_null() {
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Err(self)
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} else {
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Ok(Handle {
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node: NodeRef {
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height: self.height + 1,
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node: unsafe {
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NonZero::new(self.as_leaf().parent as *mut LeafNode<K, V>)
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},
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root: self.root,
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_marker: PhantomData
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},
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idx: self.as_leaf().parent_idx as usize,
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_marker: PhantomData
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})
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}
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}
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pub fn first_edge(self) -> Handle<Self, marker::Edge> {
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Handle::new_edge(self, 0)
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}
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pub fn last_edge(self) -> Handle<Self, marker::Edge> {
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let len = self.len();
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Handle::new_edge(self, len)
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}
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}
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impl<K, V> NodeRef<marker::Owned, K, V, marker::Leaf> {
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pub unsafe fn deallocate_and_ascend(self) -> Option<
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Handle<
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NodeRef<
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marker::Owned,
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K, V,
|
||
marker::Internal
|
||
>,
|
||
marker::Edge
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||
>
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> {
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||
let ptr = self.as_leaf() as *const LeafNode<K, V> as *const u8 as *mut u8;
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||
let ret = self.ascend().ok();
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heap::deallocate(ptr, mem::size_of::<LeafNode<K, V>>(), mem::align_of::<LeafNode<K, V>>());
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ret
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}
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}
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||
|
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impl<K, V> NodeRef<marker::Owned, K, V, marker::Internal> {
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||
pub unsafe fn deallocate_and_ascend(self) -> Option<
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Handle<
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||
NodeRef<
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||
marker::Owned,
|
||
K, V,
|
||
marker::Internal
|
||
>,
|
||
marker::Edge
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||
>
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||
> {
|
||
let ptr = self.as_internal() as *const InternalNode<K, V> as *const u8 as *mut u8;
|
||
let ret = self.ascend().ok();
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heap::deallocate(
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ptr,
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mem::size_of::<InternalNode<K, V>>(),
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mem::align_of::<InternalNode<K, V>>()
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||
);
|
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ret
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
|
||
unsafe fn cast_unchecked<NewType>(&mut self)
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||
-> NodeRef<marker::Mut, K, V, NewType> {
|
||
|
||
NodeRef {
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||
height: self.height,
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||
node: self.node,
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||
root: self.root,
|
||
_marker: PhantomData
|
||
}
|
||
}
|
||
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||
unsafe fn reborrow_mut(&mut self) -> NodeRef<marker::Mut, K, V, Type> {
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||
NodeRef {
|
||
height: self.height,
|
||
node: self.node,
|
||
root: self.root,
|
||
_marker: PhantomData
|
||
}
|
||
}
|
||
|
||
fn as_leaf_mut(&mut self) -> &mut LeafNode<K, V> {
|
||
unsafe {
|
||
&mut *(*self.node as *mut LeafNode<K, V>)
|
||
}
|
||
}
|
||
|
||
pub fn keys_mut(&mut self) -> &mut [K] {
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unsafe { self.reborrow_mut().into_slices_mut().0 }
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||
}
|
||
|
||
pub fn vals_mut(&mut self) -> &mut [V] {
|
||
unsafe { self.reborrow_mut().into_slices_mut().1 }
|
||
}
|
||
}
|
||
|
||
impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Immut<'a>, K, V, Type> {
|
||
pub fn into_slices(self) -> (&'a [K], &'a [V]) {
|
||
unsafe {
|
||
(
|
||
slice::from_raw_parts(
|
||
self.as_leaf().keys.as_ptr(),
|
||
self.len()
|
||
),
|
||
slice::from_raw_parts(
|
||
self.as_leaf().vals.as_ptr(),
|
||
self.len()
|
||
)
|
||
)
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
|
||
pub fn into_root_mut(self) -> &'a mut Root<K, V> {
|
||
unsafe {
|
||
&mut *(self.root as *mut Root<K, V>)
|
||
}
|
||
}
|
||
|
||
pub fn into_slices_mut(mut self) -> (&'a mut [K], &'a mut [V]) {
|
||
unsafe {
|
||
(
|
||
slice::from_raw_parts_mut(
|
||
&mut self.as_leaf_mut().keys as *mut [K] as *mut K,
|
||
self.len()
|
||
),
|
||
slice::from_raw_parts_mut(
|
||
&mut self.as_leaf_mut().vals as *mut [V] as *mut V,
|
||
self.len()
|
||
)
|
||
)
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Leaf> {
|
||
pub fn push(&mut self, key: K, val: V) {
|
||
// Necessary for correctness, but this is an internal module
|
||
debug_assert!(self.len() < CAPACITY);
|
||
|
||
let idx = self.len();
|
||
|
||
unsafe {
|
||
ptr::write(self.keys_mut().get_unchecked_mut(idx), key);
|
||
ptr::write(self.vals_mut().get_unchecked_mut(idx), val);
|
||
}
|
||
|
||
self.as_leaf_mut().len += 1;
|
||
}
|
||
|
||
pub fn push_front(&mut self, key: K, val: V) {
|
||
// Necessary for correctness, but this is an internal module
|
||
debug_assert!(self.len() < CAPACITY);
|
||
|
||
unsafe {
|
||
slice_insert(self.keys_mut(), 0, key);
|
||
slice_insert(self.vals_mut(), 0, val);
|
||
}
|
||
|
||
self.as_leaf_mut().len += 1;
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
|
||
pub fn push(&mut self, key: K, val: V, edge: Root<K, V>) {
|
||
// Necessary for correctness, but this is an internal module
|
||
debug_assert!(edge.height == self.height - 1);
|
||
debug_assert!(self.len() < CAPACITY);
|
||
|
||
let idx = self.len();
|
||
|
||
unsafe {
|
||
ptr::write(self.keys_mut().get_unchecked_mut(idx), key);
|
||
ptr::write(self.vals_mut().get_unchecked_mut(idx), val);
|
||
ptr::write(self.as_internal_mut().edges.get_unchecked_mut(idx + 1), edge.node);
|
||
|
||
self.as_leaf_mut().len += 1;
|
||
|
||
Handle::new_edge(self.reborrow_mut(), idx + 1).correct_parent_link();
|
||
}
|
||
}
|
||
|
||
pub fn push_front(&mut self, key: K, val: V, edge: Root<K, V>) {
|
||
// Necessary for correctness, but this is an internal module
|
||
debug_assert!(edge.height == self.height - 1);
|
||
debug_assert!(self.len() < CAPACITY);
|
||
|
||
unsafe {
|
||
slice_insert(self.keys_mut(), 0, key);
|
||
slice_insert(self.vals_mut(), 0, val);
|
||
slice_insert(
|
||
slice::from_raw_parts_mut(
|
||
self.as_internal_mut().edges.as_mut_ptr(),
|
||
self.len()+1
|
||
),
|
||
0,
|
||
edge.node
|
||
);
|
||
|
||
self.as_leaf_mut().len += 1;
|
||
|
||
for i in 0..self.len()+1 {
|
||
Handle::new_edge(self.reborrow_mut(), i).correct_parent_link();
|
||
}
|
||
}
|
||
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
|
||
pub fn pop(&mut self) -> (K, V, Option<Root<K, V>>) {
|
||
// Necessary for correctness, but this is an internal module
|
||
debug_assert!(self.len() > 0);
|
||
|
||
let idx = self.len() - 1;
|
||
|
||
unsafe {
|
||
let key = ptr::read(self.keys().get_unchecked(idx));
|
||
let val = ptr::read(self.vals().get_unchecked(idx));
|
||
let edge = match self.reborrow_mut().force() {
|
||
ForceResult::Leaf(_) => None,
|
||
ForceResult::Internal(internal) => {
|
||
let edge = ptr::read(internal.as_internal().edges.get_unchecked(idx + 1));
|
||
let mut new_root = Root { node: edge, height: internal.height - 1 };
|
||
new_root.as_mut().as_leaf_mut().parent = ptr::null();
|
||
Some(new_root)
|
||
}
|
||
};
|
||
|
||
self.as_leaf_mut().len -= 1;
|
||
(key, val, edge)
|
||
}
|
||
}
|
||
|
||
pub fn pop_front(&mut self) -> (K, V, Option<Root<K, V>>) {
|
||
// Necessary for correctness, but this is an internal module
|
||
debug_assert!(self.len() > 0);
|
||
|
||
let old_len = self.len();
|
||
|
||
unsafe {
|
||
let key = slice_remove(self.keys_mut(), 0);
|
||
let val = slice_remove(self.vals_mut(), 0);
|
||
let edge = match self.reborrow_mut().force() {
|
||
ForceResult::Leaf(_) => None,
|
||
ForceResult::Internal(mut internal) => {
|
||
let edge = slice_remove(
|
||
slice::from_raw_parts_mut(
|
||
internal.as_internal_mut().edges.as_mut_ptr(),
|
||
old_len+1
|
||
),
|
||
0
|
||
);
|
||
|
||
let mut new_root = Root { node: edge, height: internal.height - 1 };
|
||
new_root.as_mut().as_leaf_mut().parent = ptr::null();
|
||
|
||
for i in 0..old_len {
|
||
Handle::new_edge(internal.reborrow_mut(), i).correct_parent_link();
|
||
}
|
||
|
||
Some(new_root)
|
||
}
|
||
};
|
||
|
||
self.as_leaf_mut().len -= 1;
|
||
|
||
(key, val, edge)
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<BorrowType, K, V> NodeRef<BorrowType, K, V, marker::LeafOrInternal> {
|
||
pub fn force(self) -> ForceResult<
|
||
NodeRef<BorrowType, K, V, marker::Leaf>,
|
||
NodeRef<BorrowType, K, V, marker::Internal>
|
||
> {
|
||
if self.height == 0 {
|
||
ForceResult::Leaf(NodeRef {
|
||
height: self.height,
|
||
node: self.node,
|
||
root: self.root,
|
||
_marker: PhantomData
|
||
})
|
||
} else {
|
||
ForceResult::Internal(NodeRef {
|
||
height: self.height,
|
||
node: self.node,
|
||
root: self.root,
|
||
_marker: PhantomData
|
||
})
|
||
}
|
||
}
|
||
}
|
||
|
||
pub struct Handle<Node, Type> {
|
||
node: Node,
|
||
idx: usize,
|
||
_marker: PhantomData<Type>
|
||
}
|
||
|
||
impl<Node: Copy, Type> Copy for Handle<Node, Type> { }
|
||
impl<Node: Copy, Type> Clone for Handle<Node, Type> {
|
||
fn clone(&self) -> Self {
|
||
*self
|
||
}
|
||
}
|
||
|
||
impl<Node, Type> Handle<Node, Type> {
|
||
pub fn into_node(self) -> Node {
|
||
self.node
|
||
}
|
||
}
|
||
|
||
impl<BorrowType, K, V, NodeType> Handle<NodeRef<BorrowType, K, V, NodeType>, marker::KV> {
|
||
pub fn new_kv(node: NodeRef<BorrowType, K, V, NodeType>, idx: usize) -> Self {
|
||
// Necessary for correctness, but in a private module
|
||
debug_assert!(idx < node.len());
|
||
|
||
Handle {
|
||
node: node,
|
||
idx: idx,
|
||
_marker: PhantomData
|
||
}
|
||
}
|
||
|
||
pub fn left_edge(self) -> Handle<NodeRef<BorrowType, K, V, NodeType>, marker::Edge> {
|
||
Handle::new_edge(self.node, self.idx)
|
||
}
|
||
|
||
pub fn right_edge(self) -> Handle<NodeRef<BorrowType, K, V, NodeType>, marker::Edge> {
|
||
Handle::new_edge(self.node, self.idx + 1)
|
||
}
|
||
}
|
||
|
||
impl<BorrowType, K, V, NodeType, HandleType> PartialEq
|
||
for Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> {
|
||
|
||
fn eq(&self, other: &Self) -> bool {
|
||
self.node.node == other.node.node && self.idx == other.idx
|
||
}
|
||
}
|
||
|
||
impl<BorrowType, K, V, NodeType, HandleType>
|
||
Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> {
|
||
|
||
pub fn reborrow(&self)
|
||
-> Handle<NodeRef<marker::Immut, K, V, NodeType>, HandleType> {
|
||
|
||
// We can't use Handle::new_kv or Handle::new_edge because we don't know our type
|
||
Handle {
|
||
node: self.node.reborrow(),
|
||
idx: self.idx,
|
||
_marker: PhantomData
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V, NodeType, HandleType>
|
||
Handle<NodeRef<marker::Mut<'a>, K, V, NodeType>, HandleType> {
|
||
|
||
pub unsafe fn reborrow_mut(&mut self)
|
||
-> Handle<NodeRef<marker::Mut, K, V, NodeType>, HandleType> {
|
||
|
||
// We can't use Handle::new_kv or Handle::new_edge because we don't know our type
|
||
Handle {
|
||
node: self.node.reborrow_mut(),
|
||
idx: self.idx,
|
||
_marker: PhantomData
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<BorrowType, K, V, NodeType>
|
||
Handle<NodeRef<BorrowType, K, V, NodeType>, marker::Edge> {
|
||
|
||
pub fn new_edge(node: NodeRef<BorrowType, K, V, NodeType>, idx: usize) -> Self {
|
||
// Necessary for correctness, but in a private module
|
||
debug_assert!(idx <= node.len());
|
||
|
||
Handle {
|
||
node: node,
|
||
idx: idx,
|
||
_marker: PhantomData
|
||
}
|
||
}
|
||
|
||
pub fn left_kv(self)
|
||
-> Result<Handle<NodeRef<BorrowType, K, V, NodeType>, marker::KV>, Self> {
|
||
|
||
if self.idx > 0 {
|
||
Ok(Handle::new_kv(self.node, self.idx - 1))
|
||
} else {
|
||
Err(self)
|
||
}
|
||
}
|
||
|
||
pub fn right_kv(self)
|
||
-> Result<Handle<NodeRef<BorrowType, K, V, NodeType>, marker::KV>, Self> {
|
||
|
||
if self.idx < self.node.len() {
|
||
Ok(Handle::new_kv(self.node, self.idx))
|
||
} else {
|
||
Err(self)
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge> {
|
||
fn insert_fit(&mut self, key: K, val: V) -> *mut V {
|
||
// Necessary for correctness, but in a private module
|
||
debug_assert!(self.node.len() < CAPACITY);
|
||
|
||
unsafe {
|
||
slice_insert(self.node.keys_mut(), self.idx, key);
|
||
slice_insert(self.node.vals_mut(), self.idx, val);
|
||
|
||
self.node.as_leaf_mut().len += 1;
|
||
|
||
self.node.vals_mut().get_unchecked_mut(self.idx)
|
||
}
|
||
}
|
||
|
||
pub fn insert(mut self, key: K, val: V)
|
||
-> (InsertResult<'a, K, V, marker::Leaf>, *mut V) {
|
||
|
||
if self.node.len() < CAPACITY {
|
||
let ptr = self.insert_fit(key, val);
|
||
(InsertResult::Fit(Handle::new_kv(self.node, self.idx)), ptr)
|
||
} else {
|
||
let middle = Handle::new_kv(self.node, B);
|
||
let (mut left, k, v, mut right) = middle.split();
|
||
let ptr = if self.idx <= B {
|
||
unsafe {
|
||
Handle::new_edge(left.reborrow_mut(), self.idx).insert_fit(key, val)
|
||
}
|
||
} else {
|
||
unsafe {
|
||
Handle::new_edge(
|
||
right.as_mut().cast_unchecked::<marker::Leaf>(),
|
||
self.idx - (B + 1)
|
||
).insert_fit(key, val)
|
||
}
|
||
};
|
||
(InsertResult::Split(left, k, v, right), ptr)
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::Edge> {
|
||
fn correct_parent_link(mut self) {
|
||
let idx = self.idx as u16;
|
||
let ptr = self.node.as_internal_mut() as *mut _;
|
||
let mut child = self.descend();
|
||
child.as_leaf_mut().parent = ptr;
|
||
child.as_leaf_mut().parent_idx = idx;
|
||
}
|
||
|
||
unsafe fn cast_unchecked<NewType>(&mut self)
|
||
-> Handle<NodeRef<marker::Mut, K, V, NewType>, marker::Edge> {
|
||
|
||
Handle::new_edge(self.node.cast_unchecked(), self.idx)
|
||
}
|
||
|
||
fn insert_fit(&mut self, key: K, val: V, edge: Root<K, V>) {
|
||
// Necessary for correctness, but in an internal module
|
||
debug_assert!(self.node.len() < CAPACITY);
|
||
debug_assert!(edge.height == self.node.height - 1);
|
||
|
||
unsafe {
|
||
self.cast_unchecked::<marker::Leaf>().insert_fit(key, val);
|
||
|
||
slice_insert(
|
||
slice::from_raw_parts_mut(
|
||
self.node.as_internal_mut().edges.as_mut_ptr(),
|
||
self.node.len()
|
||
),
|
||
self.idx + 1,
|
||
edge.node
|
||
);
|
||
|
||
for i in (self.idx+1)..(self.node.len()+1) {
|
||
Handle::new_edge(self.node.reborrow_mut(), i).correct_parent_link();
|
||
}
|
||
}
|
||
}
|
||
|
||
pub fn insert(mut self, key: K, val: V, edge: Root<K, V>)
|
||
-> InsertResult<'a, K, V, marker::Internal> {
|
||
|
||
// Necessary for correctness, but this is an internal module
|
||
debug_assert!(edge.height == self.node.height - 1);
|
||
|
||
if self.node.len() < CAPACITY {
|
||
self.insert_fit(key, val, edge);
|
||
InsertResult::Fit(Handle::new_kv(self.node, self.idx))
|
||
} else {
|
||
let middle = Handle::new_kv(self.node, B);
|
||
let (mut left, k, v, mut right) = middle.split();
|
||
if self.idx <= B {
|
||
unsafe {
|
||
Handle::new_edge(left.reborrow_mut(), self.idx).insert_fit(key, val, edge);
|
||
}
|
||
} else {
|
||
unsafe {
|
||
Handle::new_edge(
|
||
right.as_mut().cast_unchecked::<marker::Internal>(),
|
||
self.idx - (B + 1)
|
||
).insert_fit(key, val, edge);
|
||
}
|
||
}
|
||
InsertResult::Split(left, k, v, right)
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<BorrowType, K, V>
|
||
Handle<NodeRef<BorrowType, K, V, marker::Internal>, marker::Edge> {
|
||
|
||
pub fn descend(self) -> NodeRef<BorrowType, K, V, marker::LeafOrInternal> {
|
||
NodeRef {
|
||
height: self.node.height - 1,
|
||
node: unsafe { self.node.as_internal().edges.get_unchecked(self.idx).as_ptr() },
|
||
root: self.node.root,
|
||
_marker: PhantomData
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K: 'a, V: 'a, NodeType>
|
||
Handle<NodeRef<marker::Immut<'a>, K, V, NodeType>, marker::KV> {
|
||
|
||
pub fn into_kv(self) -> (&'a K, &'a V) {
|
||
let (keys, vals) = self.node.into_slices();
|
||
unsafe {
|
||
(keys.get_unchecked(self.idx), vals.get_unchecked(self.idx))
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K: 'a, V: 'a, NodeType>
|
||
Handle<NodeRef<marker::Mut<'a>, K, V, NodeType>, marker::KV> {
|
||
|
||
pub fn into_kv_mut(self) -> (&'a mut K, &'a mut V) {
|
||
let (mut keys, mut vals) = self.node.into_slices_mut();
|
||
unsafe {
|
||
(keys.get_unchecked_mut(self.idx), vals.get_unchecked_mut(self.idx))
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V, NodeType> Handle<NodeRef<marker::Mut<'a>, K, V, NodeType>, marker::KV> {
|
||
pub fn kv_mut(&mut self) -> (&mut K, &mut V) {
|
||
unsafe {
|
||
let (mut keys, mut vals) = self.node.reborrow_mut().into_slices_mut();
|
||
(keys.get_unchecked_mut(self.idx), vals.get_unchecked_mut(self.idx))
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::KV> {
|
||
pub fn split(mut self)
|
||
-> (NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, K, V, Root<K, V>) {
|
||
unsafe {
|
||
let mut new_node = Box::new(LeafNode::new());
|
||
|
||
let k = ptr::read(self.node.keys().get_unchecked(self.idx));
|
||
let v = ptr::read(self.node.vals().get_unchecked(self.idx));
|
||
|
||
let new_len = self.node.len() - self.idx - 1;
|
||
|
||
ptr::copy_nonoverlapping(
|
||
self.node.keys().as_ptr().offset(self.idx as isize + 1),
|
||
new_node.keys.as_mut_ptr(),
|
||
new_len
|
||
);
|
||
ptr::copy_nonoverlapping(
|
||
self.node.vals().as_ptr().offset(self.idx as isize + 1),
|
||
new_node.vals.as_mut_ptr(),
|
||
new_len
|
||
);
|
||
|
||
self.node.as_leaf_mut().len = self.idx as u16;
|
||
new_node.len = new_len as u16;
|
||
|
||
(
|
||
self.node,
|
||
k, v,
|
||
Root {
|
||
node: BoxedNode::from_leaf(new_node),
|
||
height: 0
|
||
}
|
||
)
|
||
}
|
||
}
|
||
|
||
pub fn remove(mut self)
|
||
-> (Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>, K, V) {
|
||
unsafe {
|
||
let k = slice_remove(self.node.keys_mut(), self.idx);
|
||
let v = slice_remove(self.node.vals_mut(), self.idx);
|
||
self.node.as_leaf_mut().len -= 1;
|
||
(self.left_edge(), k, v)
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::KV> {
|
||
pub fn split(mut self)
|
||
-> (NodeRef<marker::Mut<'a>, K, V, marker::Internal>, K, V, Root<K, V>) {
|
||
unsafe {
|
||
let mut new_node = Box::new(InternalNode::new());
|
||
|
||
let k = ptr::read(self.node.keys().get_unchecked(self.idx));
|
||
let v = ptr::read(self.node.vals().get_unchecked(self.idx));
|
||
|
||
let height = self.node.height;
|
||
let new_len = self.node.len() - self.idx - 1;
|
||
|
||
ptr::copy_nonoverlapping(
|
||
self.node.keys().as_ptr().offset(self.idx as isize + 1),
|
||
new_node.data.keys.as_mut_ptr(),
|
||
new_len
|
||
);
|
||
ptr::copy_nonoverlapping(
|
||
self.node.vals().as_ptr().offset(self.idx as isize + 1),
|
||
new_node.data.vals.as_mut_ptr(),
|
||
new_len
|
||
);
|
||
ptr::copy_nonoverlapping(
|
||
self.node.as_internal().edges.as_ptr().offset(self.idx as isize + 1),
|
||
new_node.edges.as_mut_ptr(),
|
||
new_len + 1
|
||
);
|
||
|
||
self.node.as_leaf_mut().len = self.idx as u16;
|
||
new_node.data.len = new_len as u16;
|
||
|
||
let mut new_root = Root {
|
||
node: BoxedNode::from_internal(new_node),
|
||
height: height
|
||
};
|
||
|
||
for i in 0..(new_len+1) {
|
||
Handle::new_edge(new_root.as_mut().cast_unchecked(), i).correct_parent_link();
|
||
}
|
||
|
||
(
|
||
self.node,
|
||
k, v,
|
||
new_root
|
||
)
|
||
}
|
||
}
|
||
|
||
pub fn can_merge(&self) -> bool {
|
||
(
|
||
self.reborrow()
|
||
.left_edge()
|
||
.descend()
|
||
.len()
|
||
+ self.reborrow()
|
||
.right_edge()
|
||
.descend()
|
||
.len()
|
||
+ 1
|
||
) <= CAPACITY
|
||
}
|
||
|
||
pub fn merge(mut self)
|
||
-> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::Edge> {
|
||
let self1 = unsafe { ptr::read(&self) };
|
||
let self2 = unsafe { ptr::read(&self) };
|
||
let mut left_node = self1.left_edge().descend();
|
||
let left_len = left_node.len();
|
||
let mut right_node = self2.right_edge().descend();
|
||
let right_len = right_node.len();
|
||
|
||
// necessary for correctness, but in a private module
|
||
debug_assert!(left_len + right_len + 1 <= CAPACITY);
|
||
|
||
unsafe {
|
||
ptr::write(left_node.keys_mut().get_unchecked_mut(left_len),
|
||
slice_remove(self.node.keys_mut(), self.idx));
|
||
ptr::copy_nonoverlapping(
|
||
right_node.keys().as_ptr(),
|
||
left_node.keys_mut().as_mut_ptr().offset(left_len as isize + 1),
|
||
right_len
|
||
);
|
||
ptr::write(left_node.vals_mut().get_unchecked_mut(left_len),
|
||
slice_remove(self.node.vals_mut(), self.idx));
|
||
ptr::copy_nonoverlapping(
|
||
right_node.vals().as_ptr(),
|
||
left_node.vals_mut().as_mut_ptr().offset(left_len as isize + 1),
|
||
right_len
|
||
);
|
||
|
||
slice_remove(&mut self.node.as_internal_mut().edges, self.idx + 1);
|
||
for i in self.idx+1..self.node.len() {
|
||
Handle::new_edge(self.node.reborrow_mut(), i).correct_parent_link();
|
||
}
|
||
self.node.as_leaf_mut().len -= 1;
|
||
|
||
left_node.as_leaf_mut().len += right_len as u16 + 1;
|
||
|
||
if self.node.height > 1 {
|
||
ptr::copy_nonoverlapping(
|
||
right_node.cast_unchecked().as_internal().edges.as_ptr(),
|
||
left_node.cast_unchecked()
|
||
.as_internal_mut()
|
||
.edges
|
||
.as_mut_ptr()
|
||
.offset(left_len as isize + 1),
|
||
right_len + 1
|
||
);
|
||
|
||
for i in left_len+1..left_len+right_len+2 {
|
||
Handle::new_edge(
|
||
left_node.cast_unchecked().reborrow_mut(),
|
||
i
|
||
).correct_parent_link();
|
||
}
|
||
|
||
heap::deallocate(
|
||
*right_node.node as *mut u8,
|
||
mem::size_of::<InternalNode<K, V>>(),
|
||
mem::align_of::<InternalNode<K, V>>()
|
||
);
|
||
} else {
|
||
heap::deallocate(
|
||
*right_node.node as *mut u8,
|
||
mem::size_of::<LeafNode<K, V>>(),
|
||
mem::align_of::<LeafNode<K, V>>()
|
||
);
|
||
}
|
||
|
||
Handle::new_edge(self.node, self.idx)
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<BorrowType, K, V, HandleType>
|
||
Handle<NodeRef<BorrowType, K, V, marker::LeafOrInternal>, HandleType> {
|
||
|
||
pub fn force(self) -> ForceResult<
|
||
Handle<NodeRef<BorrowType, K, V, marker::Leaf>, HandleType>,
|
||
Handle<NodeRef<BorrowType, K, V, marker::Internal>, HandleType>
|
||
> {
|
||
match self.node.force() {
|
||
ForceResult::Leaf(node) => ForceResult::Leaf(Handle {
|
||
node: node,
|
||
idx: self.idx,
|
||
_marker: PhantomData
|
||
}),
|
||
ForceResult::Internal(node) => ForceResult::Internal(Handle {
|
||
node: node,
|
||
idx: self.idx,
|
||
_marker: PhantomData
|
||
})
|
||
}
|
||
}
|
||
}
|
||
|
||
pub enum ForceResult<Leaf, Internal> {
|
||
Leaf(Leaf),
|
||
Internal(Internal)
|
||
}
|
||
|
||
pub enum InsertResult<'a, K, V, Type> {
|
||
Fit(Handle<NodeRef<marker::Mut<'a>, K, V, Type>, marker::KV>),
|
||
Split(NodeRef<marker::Mut<'a>, K, V, Type>, K, V, Root<K, V>)
|
||
}
|
||
|
||
pub mod marker {
|
||
use core::marker::PhantomData;
|
||
|
||
pub enum Leaf { }
|
||
pub enum Internal { }
|
||
pub enum LeafOrInternal { }
|
||
|
||
pub enum Owned { }
|
||
pub struct Immut<'a>(PhantomData<&'a ()>);
|
||
pub struct Mut<'a>(PhantomData<&'a mut ()>);
|
||
|
||
pub enum KV { }
|
||
pub enum Edge { }
|
||
}
|
||
|
||
unsafe fn slice_insert<T>(slice: &mut [T], idx: usize, val: T) {
|
||
ptr::copy(
|
||
slice.as_ptr().offset(idx as isize),
|
||
slice.as_mut_ptr().offset(idx as isize + 1),
|
||
slice.len() - idx
|
||
);
|
||
ptr::write(slice.get_unchecked_mut(idx), val);
|
||
}
|
||
|
||
unsafe fn slice_remove<T>(slice: &mut [T], idx: usize) -> T {
|
||
let ret = ptr::read(slice.get_unchecked(idx));
|
||
ptr::copy(
|
||
slice.as_ptr().offset(idx as isize + 1),
|
||
slice.as_mut_ptr().offset(idx as isize),
|
||
slice.len() - idx - 1
|
||
);
|
||
ret
|
||
}
|