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Fallout: port btree to use Unique, some markers.

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This commit is contained in:
Niko Matsakis 2015-02-12 10:35:56 -05:00
parent b3c00a69f2
commit 68ebe640b6
1 changed files with 52 additions and 32 deletions
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84
src/libcollections/btree/node.rs
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@ -21,10 +21,11 @@
use core::borrow::BorrowFrom;
use core::cmp::Ordering::{Greater, Less, Equal};
use core::iter::Zip;
use core::marker::PhantomData;
use core::ops::{Deref, DerefMut, Index, IndexMut};
use core::ptr::Unique;
use core::{slice, mem, ptr, cmp, num, raw};
use alloc::heap;
use alloc::heap::{self, EMPTY};
/// Represents the result of an Insertion: either the item fit, or the node had to split
pub enum InsertionResult<K, V> {
@ -57,8 +58,8 @@ pub struct Node<K, V> {
keys: Unique<K>,
vals: Unique<V>,
// In leaf nodes, this will be null, and no space will be allocated for edges.
edges: Unique<Node<K, V>>,
// In leaf nodes, this will be None, and no space will be allocated for edges.
edges: Option<Unique<Node<K, V>>>,
// At any given time, there will be `_len` keys, `_len` values, and (in an internal node)
// `_len + 1` edges. In a leaf node, there will never be any edges.
@ -278,8 +279,11 @@ fn drop(&mut self) {
#[unsafe_destructor]
impl<K, V> Drop for Node<K, V> {
fn drop(&mut self) {
if self.keys.ptr.is_null() {
// We have already cleaned up this node.
if self.keys.is_null() {
// Since we have #[unsafe_no_drop_flag], we have to watch
// out for a null value being stored in self.keys. (Using
// null is technically a violation of the `Unique`
// requirements, though.)
return;
}
@ -292,7 +296,7 @@ fn drop(&mut self) {
self.destroy();
}
self.keys.ptr = ptr::null_mut();
self.keys = unsafe { Unique::new(0 as *mut K) };
}
}
@ -308,9 +312,9 @@ unsafe fn new_internal(capacity: usize) -> Node<K, V> {
let (vals_offset, edges_offset) = calculate_offsets_generic::<K, V>(capacity, false);
Node {
keys: Unique(buffer as *mut K),
vals: Unique(buffer.offset(vals_offset as isize) as *mut V),
edges: Unique(buffer.offset(edges_offset as isize) as *mut Node<K, V>),
keys: Unique::new(buffer as *mut K),
vals: Unique::new(buffer.offset(vals_offset as isize) as *mut V),
edges: Some(Unique::new(buffer.offset(edges_offset as isize) as *mut Node<K, V>)),
_len: 0,
_capacity: capacity,
}
@ -326,9 +330,9 @@ fn new_leaf(capacity: usize) -> Node<K, V> {
let (vals_offset, _) = calculate_offsets_generic::<K, V>(capacity, true);
Node {
keys: Unique(buffer as *mut K),
vals: Unique(unsafe { buffer.offset(vals_offset as isize) as *mut V }),
edges: Unique(ptr::null_mut()),
keys: unsafe { Unique::new(buffer as *mut K) },
vals: unsafe { Unique::new(buffer.offset(vals_offset as isize) as *mut V) },
edges: None,
_len: 0,
_capacity: capacity,
}
@ -337,18 +341,18 @@ fn new_leaf(capacity: usize) -> Node<K, V> {
unsafe fn destroy(&mut self) {
let (alignment, size) =
calculate_allocation_generic::<K, V>(self.capacity(), self.is_leaf());
heap::deallocate(self.keys.ptr as *mut u8, size, alignment);
heap::deallocate(*self.keys as *mut u8, size, alignment);
}
#[inline]
pub fn as_slices<'a>(&'a self) -> (&'a [K], &'a [V]) {
unsafe {(
mem::transmute(raw::Slice {
data: self.keys.ptr,
data: *self.keys as *const K,
len: self.len()
}),
mem::transmute(raw::Slice {
data: self.vals.ptr,
data: *self.vals as *const V,
len: self.len()
})
)}
@ -367,8 +371,12 @@ pub fn as_slices_internal<'b>(&'b self) -> NodeSlice<'b, K, V> {
&[]
} else {
unsafe {
let data = match self.edges {
None => heap::EMPTY as *const Node<K,V>,
Some(ref p) => **p as *const Node<K,V>,
};
mem::transmute(raw::Slice {
data: self.edges.ptr,
data: data,
len: self.len() + 1
})
}
@ -524,7 +532,8 @@ fn clone(&self) -> Node<K, V> {
#[derive(Copy)]
pub struct Handle<NodeRef, Type, NodeType> {
node: NodeRef,
index: usize
index: usize,
marker: PhantomData<(Type, NodeType)>,
}
pub mod handle {
@ -548,8 +557,8 @@ pub fn search<Q: ?Sized, NodeRef: Deref<Target=Node<K, V>>>(node: NodeRef, key:
// For the B configured as of this writing (B = 6), binary search was *significantly*
// worse for usizes.
match node.as_slices_internal().search_linear(key) {
(index, true) => Found(Handle { node: node, index: index }),
(index, false) => GoDown(Handle { node: node, index: index }),
(index, true) => Found(Handle { node: node, index: index, marker: PhantomData }),
(index, false) => GoDown(Handle { node: node, index: index, marker: PhantomData }),
}
}
}
@ -586,7 +595,7 @@ pub fn capacity(&self) -> usize {
/// If the node has any children
pub fn is_leaf(&self) -> bool {
self.edges.ptr.is_null()
self.edges.is_none()
}
/// if the node has too few elements
@ -618,7 +627,8 @@ impl<K, V, NodeRef, Type, NodeType> Handle<NodeRef, Type, NodeType> where
pub fn as_raw(&mut self) -> Handle<*mut Node<K, V>, Type, NodeType> {
Handle {
node: &mut *self.node as *mut _,
index: self.index
index: self.index,
marker: PhantomData,
}
}
}
@ -630,7 +640,8 @@ impl<K, V, Type, NodeType> Handle<*mut Node<K, V>, Type, NodeType> {
pub unsafe fn from_raw<'a>(&'a self) -> Handle<&'a Node<K, V>, Type, NodeType> {
Handle {
node: &*self.node,
index: self.index
index: self.index,
marker: PhantomData,
}
}
@ -640,7 +651,8 @@ pub unsafe fn from_raw<'a>(&'a self) -> Handle<&'a Node<K, V>, Type, NodeType> {
pub unsafe fn from_raw_mut<'a>(&'a mut self) -> Handle<&'a mut Node<K, V>, Type, NodeType> {
Handle {
node: &mut *self.node,
index: self.index
index: self.index,
marker: PhantomData,
}
}
}
@ -688,12 +700,14 @@ pub fn force(self) -> ForceResult<NodeRef, Type> {
if self.node.is_leaf() {
Leaf(Handle {
node: self.node,
index: self.index
index: self.index,
marker: PhantomData,
})
} else {
Internal(Handle {
node: self.node,
index: self.index
index: self.index,
marker: PhantomData,
})
}
}
@ -826,7 +840,8 @@ impl<K, V, NodeRef, NodeType> Handle<NodeRef, handle::Edge, NodeType> where
unsafe fn left_kv<'a>(&'a mut self) -> Handle<&'a mut Node<K, V>, handle::KV, NodeType> {
Handle {
node: &mut *self.node,
index: self.index - 1
index: self.index - 1,
marker: PhantomData,
}
}
@ -836,7 +851,8 @@ unsafe fn left_kv<'a>(&'a mut self) -> Handle<&'a mut Node<K, V>, handle::KV, No
unsafe fn right_kv<'a>(&'a mut self) -> Handle<&'a mut Node<K, V>, handle::KV, NodeType> {
Handle {
node: &mut *self.node,
index: self.index
index: self.index,
marker: PhantomData,
}
}
}
@ -876,7 +892,8 @@ pub fn into_kv_mut(self) -> (&'a mut K, &'a mut V) {
pub fn into_left_edge(self) -> Handle<&'a mut Node<K, V>, handle::Edge, NodeType> {
Handle {
node: &mut *self.node,
index: self.index
index: self.index,
marker: PhantomData,
}
}
}
@ -926,7 +943,8 @@ impl<K, V, NodeRef, NodeType> Handle<NodeRef, handle::KV, NodeType> where
pub fn left_edge<'a>(&'a mut self) -> Handle<&'a mut Node<K, V>, handle::Edge, NodeType> {
Handle {
node: &mut *self.node,
index: self.index
index: self.index,
marker: PhantomData,
}
}
@ -935,7 +953,8 @@ pub fn left_edge<'a>(&'a mut self) -> Handle<&'a mut Node<K, V>, handle::Edge, N
pub fn right_edge<'a>(&'a mut self) -> Handle<&'a mut Node<K, V>, handle::Edge, NodeType> {
Handle {
node: &mut *self.node,
index: self.index + 1
index: self.index + 1,
marker: PhantomData,
}
}
}
@ -1044,7 +1063,8 @@ pub fn kv_handle(&mut self, index: usize) -> Handle<&mut Node<K, V>, handle::KV,
debug_assert!(index < self.len(), "kv_handle index out of bounds");
Handle {
node: self,
index: index
index: index,
marker: PhantomData,
}
}
@ -1064,7 +1084,7 @@ pub fn into_iter(self) -> MoveTraversal<K, V> {
vals: RawItems::from_slice(self.vals()),
edges: RawItems::from_slice(self.edges()),
ptr: self.keys.ptr as *mut u8,
ptr: *self.keys as *mut u8,
capacity: self.capacity(),
is_leaf: self.is_leaf()
},