RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-29 14:20:29 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity
0df1deab9b
llvm-mirror/include/llvm/ADT/IntervalMap.h
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo 
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

2168 lines
73 KiB
C++
Raw Blame History

//===- llvm/ADT/IntervalMap.h - A sorted interval map -----------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements a coalescing interval map for small objects.
//
// KeyT objects are mapped to ValT objects. Intervals of keys that map to the
// same value are represented in a compressed form.
//
// Iterators provide ordered access to the compressed intervals rather than the
// individual keys, and insert and erase operations use key intervals as well.
//
// Like SmallVector, IntervalMap will store the first N intervals in the map
// object itself without any allocations. When space is exhausted it switches to
// a B+-tree representation with very small overhead for small key and value
// objects.
//
// A Traits class specifies how keys are compared. It also allows IntervalMap to
// work with both closed and half-open intervals.
//
// Keys and values are not stored next to each other in a std::pair, so we don't
// provide such a value_type. Dereferencing iterators only returns the mapped
// value. The interval bounds are accessible through the start() and stop()
// iterator methods.
//
// IntervalMap is optimized for small key and value objects, 4 or 8 bytes each
// is the optimal size. For large objects use std::map instead.
//
//===----------------------------------------------------------------------===//
//
// Synopsis:
//
// template <typename KeyT, typename ValT, unsigned N, typename Traits>
// class IntervalMap {
// public:
// typedef KeyT key_type;
// typedef ValT mapped_type;
// typedef RecyclingAllocator<...> Allocator;
// class iterator;
// class const_iterator;
//
// explicit IntervalMap(Allocator&);
// ~IntervalMap():
//
// bool empty() const;
// KeyT start() const;
// KeyT stop() const;
// ValT lookup(KeyT x, Value NotFound = Value()) const;
//
// const_iterator begin() const;
// const_iterator end() const;
// iterator begin();
// iterator end();
// const_iterator find(KeyT x) const;
// iterator find(KeyT x);
//
// void insert(KeyT a, KeyT b, ValT y);
// void clear();
// };
//
// template <typename KeyT, typename ValT, unsigned N, typename Traits>
// class IntervalMap::const_iterator :
// public std::iterator<std::bidirectional_iterator_tag, ValT> {
// public:
// bool operator==(const const_iterator &) const;
// bool operator!=(const const_iterator &) const;
// bool valid() const;
//
// const KeyT &start() const;
// const KeyT &stop() const;
// const ValT &value() const;
// const ValT &operator*() const;
// const ValT *operator->() const;
//
// const_iterator &operator++();
// const_iterator &operator++(int);
// const_iterator &operator--();
// const_iterator &operator--(int);
// void goToBegin();
// void goToEnd();
// void find(KeyT x);
// void advanceTo(KeyT x);
// };
//
// template <typename KeyT, typename ValT, unsigned N, typename Traits>
// class IntervalMap::iterator : public const_iterator {
// public:
// void insert(KeyT a, KeyT b, Value y);
// void erase();
// };
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_INTERVALMAP_H
#define LLVM_ADT_INTERVALMAP_H
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/bit.h"
#include "llvm/Support/AlignOf.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/RecyclingAllocator.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>
#include <new>
#include <utility>
namespace llvm {
//===----------------------------------------------------------------------===//
//--- Key traits ---//
//===----------------------------------------------------------------------===//
//
// The IntervalMap works with closed or half-open intervals.
// Adjacent intervals that map to the same value are coalesced.
//
// The IntervalMapInfo traits class is used to determine if a key is contained
// in an interval, and if two intervals are adjacent so they can be coalesced.
// The provided implementation works for closed integer intervals, other keys
// probably need a specialized version.
//
// The point x is contained in [a;b] when !startLess(x, a) && !stopLess(b, x).
//
// It is assumed that (a;b] half-open intervals are not used, only [a;b) is
// allowed. This is so that stopLess(a, b) can be used to determine if two
// intervals overlap.
//
//===----------------------------------------------------------------------===//
template <typename T>
struct IntervalMapInfo {
/// startLess - Return true if x is not in [a;b].
/// This is x < a both for closed intervals and for [a;b) half-open intervals.
static inline bool startLess(const T &x, const T &a) {
return x < a;
}
/// stopLess - Return true if x is not in [a;b].
/// This is b < x for a closed interval, b <= x for [a;b) half-open intervals.
static inline bool stopLess(const T &b, const T &x) {
return b < x;
}
/// adjacent - Return true when the intervals [x;a] and [b;y] can coalesce.
/// This is a+1 == b for closed intervals, a == b for half-open intervals.
static inline bool adjacent(const T &a, const T &b) {
return a+1 == b;
}
/// nonEmpty - Return true if [a;b] is non-empty.
/// This is a <= b for a closed interval, a < b for [a;b) half-open intervals.
static inline bool nonEmpty(const T &a, const T &b) {
return a <= b;
}
};
template <typename T>
struct IntervalMapHalfOpenInfo {
/// startLess - Return true if x is not in [a;b).
static inline bool startLess(const T &x, const T &a) {
return x < a;
}
/// stopLess - Return true if x is not in [a;b).
static inline bool stopLess(const T &b, const T &x) {
return b <= x;
}
/// adjacent - Return true when the intervals [x;a) and [b;y) can coalesce.
static inline bool adjacent(const T &a, const T &b) {
return a == b;
}
/// nonEmpty - Return true if [a;b) is non-empty.
static inline bool nonEmpty(const T &a, const T &b) {
return a < b;
}
};
/// IntervalMapImpl - Namespace used for IntervalMap implementation details.
/// It should be considered private to the implementation.
namespace IntervalMapImpl {
using IdxPair = std::pair<unsigned,unsigned>;
//===----------------------------------------------------------------------===//
//--- IntervalMapImpl::NodeBase ---//
//===----------------------------------------------------------------------===//
//
// Both leaf and branch nodes store vectors of pairs.
// Leaves store ((KeyT, KeyT), ValT) pairs, branches use (NodeRef, KeyT).
//
// Keys and values are stored in separate arrays to avoid padding caused by
// different object alignments. This also helps improve locality of reference
// when searching the keys.
//
// The nodes don't know how many elements they contain - that information is
// stored elsewhere. Omitting the size field prevents padding and allows a node
// to fill the allocated cache lines completely.
//
// These are typical key and value sizes, the node branching factor (N), and
// wasted space when nodes are sized to fit in three cache lines (192 bytes):
//
// T1 T2 N Waste Used by
// 4 4 24 0 Branch<4> (32-bit pointers)
// 8 4 16 0 Leaf<4,4>, Branch<4>
// 8 8 12 0 Leaf<4,8>, Branch<8>
// 16 4 9 12 Leaf<8,4>
// 16 8 8 0 Leaf<8,8>
//
//===----------------------------------------------------------------------===//
template <typename T1, typename T2, unsigned N>
class NodeBase {
public:
enum { Capacity = N };
T1 first[N];
T2 second[N];
/// copy - Copy elements from another node.
/// @param Other Node elements are copied from.
/// @param i Beginning of the source range in other.
/// @param j Beginning of the destination range in this.
/// @param Count Number of elements to copy.
template <unsigned M>
void copy(const NodeBase<T1, T2, M> &Other, unsigned i,
unsigned j, unsigned Count) {
assert(i + Count <= M && "Invalid source range");
assert(j + Count <= N && "Invalid dest range");
for (unsigned e = i + Count; i != e; ++i, ++j) {
first[j] = Other.first[i];
second[j] = Other.second[i];
}
}
/// moveLeft - Move elements to the left.
/// @param i Beginning of the source range.
/// @param j Beginning of the destination range.
/// @param Count Number of elements to copy.
void moveLeft(unsigned i, unsigned j, unsigned Count) {
assert(j <= i && "Use moveRight shift elements right");
copy(*this, i, j, Count);
}
/// moveRight - Move elements to the right.
/// @param i Beginning of the source range.
/// @param j Beginning of the destination range.
/// @param Count Number of elements to copy.
void moveRight(unsigned i, unsigned j, unsigned Count) {
assert(i <= j && "Use moveLeft shift elements left");
assert(j + Count <= N && "Invalid range");
while (Count--) {
first[j + Count] = first[i + Count];
second[j + Count] = second[i + Count];
}
}
/// erase - Erase elements [i;j).
/// @param i Beginning of the range to erase.
/// @param j End of the range. (Exclusive).
/// @param Size Number of elements in node.
void erase(unsigned i, unsigned j, unsigned Size) {
moveLeft(j, i, Size - j);
}
/// erase - Erase element at i.
/// @param i Index of element to erase.
/// @param Size Number of elements in node.
void erase(unsigned i, unsigned Size) {
erase(i, i+1, Size);
}
/// shift - Shift elements [i;size) 1 position to the right.
/// @param i Beginning of the range to move.
/// @param Size Number of elements in node.
void shift(unsigned i, unsigned Size) {
moveRight(i, i + 1, Size - i);
}
/// transferToLeftSib - Transfer elements to a left sibling node.
/// @param Size Number of elements in this.
/// @param Sib Left sibling node.
/// @param SSize Number of elements in sib.
/// @param Count Number of elements to transfer.
void transferToLeftSib(unsigned Size, NodeBase &Sib, unsigned SSize,
unsigned Count) {
Sib.copy(*this, 0, SSize, Count);
erase(0, Count, Size);
}
/// transferToRightSib - Transfer elements to a right sibling node.
/// @param Size Number of elements in this.
/// @param Sib Right sibling node.
/// @param SSize Number of elements in sib.
/// @param Count Number of elements to transfer.
void transferToRightSib(unsigned Size, NodeBase &Sib, unsigned SSize,
unsigned Count) {
Sib.moveRight(0, Count, SSize);
Sib.copy(*this, Size-Count, 0, Count);
}
/// adjustFromLeftSib - Adjust the number if elements in this node by moving
/// elements to or from a left sibling node.
/// @param Size Number of elements in this.
/// @param Sib Right sibling node.
/// @param SSize Number of elements in sib.
/// @param Add The number of elements to add to this node, possibly < 0.
/// @return Number of elements added to this node, possibly negative.
int adjustFromLeftSib(unsigned Size, NodeBase &Sib, unsigned SSize, int Add) {
if (Add > 0) {
// We want to grow, copy from sib.
unsigned Count = std::min(std::min(unsigned(Add), SSize), N - Size);
Sib.transferToRightSib(SSize, *this, Size, Count);
return Count;
} else {
// We want to shrink, copy to sib.
unsigned Count = std::min(std::min(unsigned(-Add), Size), N - SSize);
transferToLeftSib(Size, Sib, SSize, Count);
return -Count;
}
}
};
/// IntervalMapImpl::adjustSiblingSizes - Move elements between sibling nodes.
/// @param Node Array of pointers to sibling nodes.
/// @param Nodes Number of nodes.
/// @param CurSize Array of current node sizes, will be overwritten.
/// @param NewSize Array of desired node sizes.
template <typename NodeT>
void adjustSiblingSizes(NodeT *Node[], unsigned Nodes,
unsigned CurSize[], const unsigned NewSize[]) {
// Move elements right.
for (int n = Nodes - 1; n; --n) {
if (CurSize[n] == NewSize[n])
continue;
for (int m = n - 1; m != -1; --m) {
int d = Node[n]->adjustFromLeftSib(CurSize[n], *Node[m], CurSize[m],
NewSize[n] - CurSize[n]);
CurSize[m] -= d;
CurSize[n] += d;
// Keep going if the current node was exhausted.
if (CurSize[n] >= NewSize[n])
break;
}
}
if (Nodes == 0)
return;
// Move elements left.
for (unsigned n = 0; n != Nodes - 1; ++n) {
if (CurSize[n] == NewSize[n])
continue;
for (unsigned m = n + 1; m != Nodes; ++m) {
int d = Node[m]->adjustFromLeftSib(CurSize[m], *Node[n], CurSize[n],
CurSize[n] - NewSize[n]);
CurSize[m] += d;
CurSize[n] -= d;
// Keep going if the current node was exhausted.
if (CurSize[n] >= NewSize[n])
break;
}
}
#ifndef NDEBUG
for (unsigned n = 0; n != Nodes; n++)
assert(CurSize[n] == NewSize[n] && "Insufficient element shuffle");
#endif
}
/// IntervalMapImpl::distribute - Compute a new distribution of node elements
/// after an overflow or underflow. Reserve space for a new element at Position,
/// and compute the node that will hold Position after redistributing node
/// elements.
///
/// It is required that
///
/// Elements == sum(CurSize), and
/// Elements + Grow <= Nodes * Capacity.
///
/// NewSize[] will be filled in such that:
///
/// sum(NewSize) == Elements, and
/// NewSize[i] <= Capacity.
///
/// The returned index is the node where Position will go, so:
///
/// sum(NewSize[0..idx-1]) <= Position
/// sum(NewSize[0..idx]) >= Position
///
/// The last equality, sum(NewSize[0..idx]) == Position, can only happen when
/// Grow is set and NewSize[idx] == Capacity-1. The index points to the node
/// before the one holding the Position'th element where there is room for an
/// insertion.
///
/// @param Nodes The number of nodes.
/// @param Elements Total elements in all nodes.
/// @param Capacity The capacity of each node.
/// @param CurSize Array[Nodes] of current node sizes, or NULL.
/// @param NewSize Array[Nodes] to receive the new node sizes.
/// @param Position Insert position.
/// @param Grow Reserve space for a new element at Position.
/// @return (node, offset) for Position.
IdxPair distribute(unsigned Nodes, unsigned Elements, unsigned Capacity,
const unsigned *CurSize, unsigned NewSize[],
unsigned Position, bool Grow);
//===----------------------------------------------------------------------===//
//--- IntervalMapImpl::NodeSizer ---//
//===----------------------------------------------------------------------===//
//
// Compute node sizes from key and value types.
//
// The branching factors are chosen to make nodes fit in three cache lines.
// This may not be possible if keys or values are very large. Such large objects
// are handled correctly, but a std::map would probably give better performance.
//
//===----------------------------------------------------------------------===//
enum {
// Cache line size. Most architectures have 32 or 64 byte cache lines.
// We use 64 bytes here because it provides good branching factors.
Log2CacheLine = 6,
CacheLineBytes = 1 << Log2CacheLine,
DesiredNodeBytes = 3 * CacheLineBytes
};
template <typename KeyT, typename ValT>
struct NodeSizer {
enum {
// Compute the leaf node branching factor that makes a node fit in three
// cache lines. The branching factor must be at least 3, or some B+-tree
// balancing algorithms won't work.
// LeafSize can't be larger than CacheLineBytes. This is required by the
// PointerIntPair used by NodeRef.
DesiredLeafSize = DesiredNodeBytes /
static_cast<unsigned>(2*sizeof(KeyT)+sizeof(ValT)),
MinLeafSize = 3,
LeafSize = DesiredLeafSize > MinLeafSize ? DesiredLeafSize : MinLeafSize
};
using LeafBase = NodeBase<std::pair<KeyT, KeyT>, ValT, LeafSize>;
enum {
// Now that we have the leaf branching factor, compute the actual allocation
// unit size by rounding up to a whole number of cache lines.
AllocBytes = (sizeof(LeafBase) + CacheLineBytes-1) & ~(CacheLineBytes-1),
// Determine the branching factor for branch nodes.
BranchSize = AllocBytes /
static_cast<unsigned>(sizeof(KeyT) + sizeof(void*))
};
/// Allocator - The recycling allocator used for both branch and leaf nodes.
/// This typedef is very likely to be identical for all IntervalMaps with
/// reasonably sized entries, so the same allocator can be shared among
/// different kinds of maps.
using Allocator =
RecyclingAllocator<BumpPtrAllocator, char, AllocBytes, CacheLineBytes>;
};
//===----------------------------------------------------------------------===//
//--- IntervalMapImpl::NodeRef ---//
//===----------------------------------------------------------------------===//
//
// B+-tree nodes can be leaves or branches, so we need a polymorphic node
// pointer that can point to both kinds.
//
// All nodes are cache line aligned and the low 6 bits of a node pointer are
// always 0. These bits are used to store the number of elements in the
// referenced node. Besides saving space, placing node sizes in the parents
// allow tree balancing algorithms to run without faulting cache lines for nodes
// that may not need to be modified.
//
// A NodeRef doesn't know whether it references a leaf node or a branch node.
// It is the responsibility of the caller to use the correct types.
//
// Nodes are never supposed to be empty, and it is invalid to store a node size
// of 0 in a NodeRef. The valid range of sizes is 1-64.
//
//===----------------------------------------------------------------------===//
class NodeRef {
struct CacheAlignedPointerTraits {
static inline void *getAsVoidPointer(void *P) { return P; }
static inline void *getFromVoidPointer(void *P) { return P; }
enum { NumLowBitsAvailable = Log2CacheLine };
};
PointerIntPair<void*, Log2CacheLine, unsigned, CacheAlignedPointerTraits> pip;
public:
/// NodeRef - Create a null ref.
NodeRef() = default;
/// operator bool - Detect a null ref.
explicit operator bool() const { return pip.getOpaqueValue(); }
/// NodeRef - Create a reference to the node p with n elements.
template <typename NodeT>
NodeRef(NodeT *p, unsigned n) : pip(p, n - 1) {
assert(n <= NodeT::Capacity && "Size too big for node");
}
/// size - Return the number of elements in the referenced node.
unsigned size() const { return pip.getInt() + 1; }
/// setSize - Update the node size.
void setSize(unsigned n) { pip.setInt(n - 1); }
/// subtree - Access the i'th subtree reference in a branch node.
/// This depends on branch nodes storing the NodeRef array as their first
/// member.
NodeRef &subtree(unsigned i) const {
return reinterpret_cast<NodeRef*>(pip.getPointer())[i];
}
/// get - Dereference as a NodeT reference.
template <typename NodeT>
NodeT &get() const {
return *reinterpret_cast<NodeT*>(pip.getPointer());
}
bool operator==(const NodeRef &RHS) const {
if (pip == RHS.pip)
return true;
assert(pip.getPointer() != RHS.pip.getPointer() && "Inconsistent NodeRefs");
return false;
}
bool operator!=(const NodeRef &RHS) const {
return !operator==(RHS);
}
};
//===----------------------------------------------------------------------===//
//--- IntervalMapImpl::LeafNode ---//
//===----------------------------------------------------------------------===//
//
// Leaf nodes store up to N disjoint intervals with corresponding values.
//
// The intervals are kept sorted and fully coalesced so there are no adjacent
// intervals mapping to the same value.
//
// These constraints are always satisfied:
//
// - Traits::stopLess(start(i), stop(i)) - Non-empty, sane intervals.
//
// - Traits::stopLess(stop(i), start(i + 1) - Sorted.
//
// - value(i) != value(i + 1) || !Traits::adjacent(stop(i), start(i + 1))
// - Fully coalesced.
//
//===----------------------------------------------------------------------===//
template <typename KeyT, typename ValT, unsigned N, typename Traits>
class LeafNode : public NodeBase<std::pair<KeyT, KeyT>, ValT, N> {
public:
const KeyT &start(unsigned i) const { return this->first[i].first; }
const KeyT &stop(unsigned i) const { return this->first[i].second; }
const ValT &value(unsigned i) const { return this->second[i]; }
KeyT &start(unsigned i) { return this->first[i].first; }
KeyT &stop(unsigned i) { return this->first[i].second; }
ValT &value(unsigned i) { return this->second[i]; }
/// findFrom - Find the first interval after i that may contain x.
/// @param i Starting index for the search.
/// @param Size Number of elements in node.
/// @param x Key to search for.
/// @return First index with !stopLess(key[i].stop, x), or size.
/// This is the first interval that can possibly contain x.
unsigned findFrom(unsigned i, unsigned Size, KeyT x) const {
assert(i <= Size && Size <= N && "Bad indices");
assert((i == 0 || Traits::stopLess(stop(i - 1), x)) &&
"Index is past the needed point");
while (i != Size && Traits::stopLess(stop(i), x)) ++i;
return i;
}
/// safeFind - Find an interval that is known to exist. This is the same as
/// findFrom except is it assumed that x is at least within range of the last
/// interval.
/// @param i Starting index for the search.
/// @param x Key to search for.
/// @return First index with !stopLess(key[i].stop, x), never size.
/// This is the first interval that can possibly contain x.
unsigned safeFind(unsigned i, KeyT x) const {
assert(i < N && "Bad index");
assert((i == 0 || Traits::stopLess(stop(i - 1), x)) &&
"Index is past the needed point");
while (Traits::stopLess(stop(i), x)) ++i;
assert(i < N && "Unsafe intervals");
return i;
}
/// safeLookup - Lookup mapped value for a safe key.
/// It is assumed that x is within range of the last entry.
/// @param x Key to search for.
/// @param NotFound Value to return if x is not in any interval.
/// @return The mapped value at x or NotFound.
ValT safeLookup(KeyT x, ValT NotFound) const {
unsigned i = safeFind(0, x);
return Traits::startLess(x, start(i)) ? NotFound : value(i);
}
unsigned insertFrom(unsigned &Pos, unsigned Size, KeyT a, KeyT b, ValT y);
};
/// insertFrom - Add mapping of [a;b] to y if possible, coalescing as much as
/// possible. This may cause the node to grow by 1, or it may cause the node
/// to shrink because of coalescing.
/// @param Pos Starting index = insertFrom(0, size, a)
/// @param Size Number of elements in node.
/// @param a Interval start.
/// @param b Interval stop.
/// @param y Value be mapped.
/// @return (insert position, new size), or (i, Capacity+1) on overflow.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
unsigned LeafNode<KeyT, ValT, N, Traits>::
insertFrom(unsigned &Pos, unsigned Size, KeyT a, KeyT b, ValT y) {
unsigned i = Pos;
assert(i <= Size && Size <= N && "Invalid index");
assert(!Traits::stopLess(b, a) && "Invalid interval");
// Verify the findFrom invariant.
assert((i == 0 || Traits::stopLess(stop(i - 1), a)));
assert((i == Size || !Traits::stopLess(stop(i), a)));
assert((i == Size || Traits::stopLess(b, start(i))) && "Overlapping insert");
// Coalesce with previous interval.
if (i && value(i - 1) == y && Traits::adjacent(stop(i - 1), a)) {
Pos = i - 1;
// Also coalesce with next interval?
if (i != Size && value(i) == y && Traits::adjacent(b, start(i))) {
stop(i - 1) = stop(i);
this->erase(i, Size);
return Size - 1;
}
stop(i - 1) = b;
return Size;
}
// Detect overflow.
if (i == N)
return N + 1;
// Add new interval at end.
if (i == Size) {
start(i) = a;
stop(i) = b;
value(i) = y;
return Size + 1;
}
// Try to coalesce with following interval.
if (value(i) == y && Traits::adjacent(b, start(i))) {
start(i) = a;
return Size;
}
// We must insert before i. Detect overflow.
if (Size == N)
return N + 1;
// Insert before i.
this->shift(i, Size);
start(i) = a;
stop(i) = b;
value(i) = y;
return Size + 1;
}
//===----------------------------------------------------------------------===//
//--- IntervalMapImpl::BranchNode ---//
//===----------------------------------------------------------------------===//
//
// A branch node stores references to 1--N subtrees all of the same height.
//
// The key array in a branch node holds the rightmost stop key of each subtree.
// It is redundant to store the last stop key since it can be found in the
// parent node, but doing so makes tree balancing a lot simpler.
//
// It is unusual for a branch node to only have one subtree, but it can happen
// in the root node if it is smaller than the normal nodes.
//
// When all of the leaf nodes from all the subtrees are concatenated, they must
// satisfy the same constraints as a single leaf node. They must be sorted,
// sane, and fully coalesced.
//
//===----------------------------------------------------------------------===//
template <typename KeyT, typename ValT, unsigned N, typename Traits>
class BranchNode : public NodeBase<NodeRef, KeyT, N> {
public:
const KeyT &stop(unsigned i) const { return this->second[i]; }
const NodeRef &subtree(unsigned i) const { return this->first[i]; }
KeyT &stop(unsigned i) { return this->second[i]; }
NodeRef &subtree(unsigned i) { return this->first[i]; }
/// findFrom - Find the first subtree after i that may contain x.
/// @param i Starting index for the search.
/// @param Size Number of elements in node.
/// @param x Key to search for.
/// @return First index with !stopLess(key[i], x), or size.
/// This is the first subtree that can possibly contain x.
unsigned findFrom(unsigned i, unsigned Size, KeyT x) const {
assert(i <= Size && Size <= N && "Bad indices");
assert((i == 0 || Traits::stopLess(stop(i - 1), x)) &&
"Index to findFrom is past the needed point");
while (i != Size && Traits::stopLess(stop(i), x)) ++i;
return i;
}
/// safeFind - Find a subtree that is known to exist. This is the same as
/// findFrom except is it assumed that x is in range.
/// @param i Starting index for the search.
/// @param x Key to search for.
/// @return First index with !stopLess(key[i], x), never size.
/// This is the first subtree that can possibly contain x.
unsigned safeFind(unsigned i, KeyT x) const {
assert(i < N && "Bad index");
assert((i == 0 || Traits::stopLess(stop(i - 1), x)) &&
"Index is past the needed point");
while (Traits::stopLess(stop(i), x)) ++i;
assert(i < N && "Unsafe intervals");
return i;
}
/// safeLookup - Get the subtree containing x, Assuming that x is in range.
/// @param x Key to search for.
/// @return Subtree containing x
NodeRef safeLookup(KeyT x) const {
return subtree(safeFind(0, x));
}
/// insert - Insert a new (subtree, stop) pair.
/// @param i Insert position, following entries will be shifted.
/// @param Size Number of elements in node.
/// @param Node Subtree to insert.
/// @param Stop Last key in subtree.
void insert(unsigned i, unsigned Size, NodeRef Node, KeyT Stop) {
assert(Size < N && "branch node overflow");
assert(i <= Size && "Bad insert position");
this->shift(i, Size);
subtree(i) = Node;
stop(i) = Stop;
}
};
//===----------------------------------------------------------------------===//
//--- IntervalMapImpl::Path ---//
//===----------------------------------------------------------------------===//
//
// A Path is used by iterators to represent a position in a B+-tree, and the
// path to get there from the root.
//
// The Path class also contains the tree navigation code that doesn't have to
// be templatized.
//
//===----------------------------------------------------------------------===//
class Path {
/// Entry - Each step in the path is a node pointer and an offset into that
/// node.
struct Entry {
void *node;
unsigned size;
unsigned offset;
Entry(void *Node, unsigned Size, unsigned Offset)
: node(Node), size(Size), offset(Offset) {}
Entry(NodeRef Node, unsigned Offset)
: node(&Node.subtree(0)), size(Node.size()), offset(Offset) {}
NodeRef &subtree(unsigned i) const {
return reinterpret_cast<NodeRef*>(node)[i];
}
};
/// path - The path entries, path[0] is the root node, path.back() is a leaf.
SmallVector<Entry, 4> path;
public:
// Node accessors.
template <typename NodeT> NodeT &node(unsigned Level) const {
return *reinterpret_cast<NodeT*>(path[Level].node);
}
unsigned size(unsigned Level) const { return path[Level].size; }
unsigned offset(unsigned Level) const { return path[Level].offset; }
unsigned &offset(unsigned Level) { return path[Level].offset; }
// Leaf accessors.
template <typename NodeT> NodeT &leaf() const {
return *reinterpret_cast<NodeT*>(path.back().node);
}
unsigned leafSize() const { return path.back().size; }
unsigned leafOffset() const { return path.back().offset; }
unsigned &leafOffset() { return path.back().offset; }
/// valid - Return true if path is at a valid node, not at end().
bool valid() const {
return !path.empty() && path.front().offset < path.front().size;
}
/// height - Return the height of the tree corresponding to this path.
/// This matches map->height in a full path.
unsigned height() const { return path.size() - 1; }
/// subtree - Get the subtree referenced from Level. When the path is
/// consistent, node(Level + 1) == subtree(Level).
/// @param Level 0..height-1. The leaves have no subtrees.
NodeRef &subtree(unsigned Level) const {
return path[Level].subtree(path[Level].offset);
}
/// reset - Reset cached information about node(Level) from subtree(Level -1).
/// @param Level 1..height. THe node to update after parent node changed.
void reset(unsigned Level) {
path[Level] = Entry(subtree(Level - 1), offset(Level));
}
/// push - Add entry to path.
/// @param Node Node to add, should be subtree(path.size()-1).
/// @param Offset Offset into Node.
void push(NodeRef Node, unsigned Offset) {
path.push_back(Entry(Node, Offset));
}
/// pop - Remove the last path entry.
void pop() {
path.pop_back();
}
/// setSize - Set the size of a node both in the path and in the tree.
/// @param Level 0..height. Note that setting the root size won't change
/// map->rootSize.
/// @param Size New node size.
void setSize(unsigned Level, unsigned Size) {
path[Level].size = Size;
if (Level)
subtree(Level - 1).setSize(Size);
}
/// setRoot - Clear the path and set a new root node.
/// @param Node New root node.
/// @param Size New root size.
/// @param Offset Offset into root node.
void setRoot(void *Node, unsigned Size, unsigned Offset) {
path.clear();
path.push_back(Entry(Node, Size, Offset));
}
/// replaceRoot - Replace the current root node with two new entries after the
/// tree height has increased.
/// @param Root The new root node.
/// @param Size Number of entries in the new root.
/// @param Offsets Offsets into the root and first branch nodes.
void replaceRoot(void *Root, unsigned Size, IdxPair Offsets);
/// getLeftSibling - Get the left sibling node at Level, or a null NodeRef.
/// @param Level Get the sibling to node(Level).
/// @return Left sibling, or NodeRef().
NodeRef getLeftSibling(unsigned Level) const;
/// moveLeft - Move path to the left sibling at Level. Leave nodes below Level
/// unaltered.
/// @param Level Move node(Level).
void moveLeft(unsigned Level);
/// fillLeft - Grow path to Height by taking leftmost branches.
/// @param Height The target height.
void fillLeft(unsigned Height) {
while (height() < Height)
push(subtree(height()), 0);
}
/// getLeftSibling - Get the left sibling node at Level, or a null NodeRef.
/// @param Level Get the sinbling to node(Level).
/// @return Left sibling, or NodeRef().
NodeRef getRightSibling(unsigned Level) const;
/// moveRight - Move path to the left sibling at Level. Leave nodes below
/// Level unaltered.
/// @param Level Move node(Level).
void moveRight(unsigned Level);
/// atBegin - Return true if path is at begin().
bool atBegin() const {
for (unsigned i = 0, e = path.size(); i != e; ++i)
if (path[i].offset != 0)
return false;
return true;
}
/// atLastEntry - Return true if the path is at the last entry of the node at
/// Level.
/// @param Level Node to examine.
bool atLastEntry(unsigned Level) const {
return path[Level].offset == path[Level].size - 1;
}
/// legalizeForInsert - Prepare the path for an insertion at Level. When the
/// path is at end(), node(Level) may not be a legal node. legalizeForInsert
/// ensures that node(Level) is real by moving back to the last node at Level,
/// and setting offset(Level) to size(Level) if required.
/// @param Level The level where an insertion is about to take place.
void legalizeForInsert(unsigned Level) {
if (valid())
return;
moveLeft(Level);
++path[Level].offset;
}
};
} // end namespace IntervalMapImpl
//===----------------------------------------------------------------------===//
//--- IntervalMap ----//
//===----------------------------------------------------------------------===//
template <typename KeyT, typename ValT,
unsigned N = IntervalMapImpl::NodeSizer<KeyT, ValT>::LeafSize,
typename Traits = IntervalMapInfo<KeyT>>
class IntervalMap {
using Sizer = IntervalMapImpl::NodeSizer<KeyT, ValT>;
using Leaf = IntervalMapImpl::LeafNode<KeyT, ValT, Sizer::LeafSize, Traits>;
using Branch =
IntervalMapImpl::BranchNode<KeyT, ValT, Sizer::BranchSize, Traits>;
using RootLeaf = IntervalMapImpl::LeafNode<KeyT, ValT, N, Traits>;
using IdxPair = IntervalMapImpl::IdxPair;
// The RootLeaf capacity is given as a template parameter. We must compute the
// corresponding RootBranch capacity.
enum {
DesiredRootBranchCap = (sizeof(RootLeaf) - sizeof(KeyT)) /
(sizeof(KeyT) + sizeof(IntervalMapImpl::NodeRef)),
RootBranchCap = DesiredRootBranchCap ? DesiredRootBranchCap : 1
};
using RootBranch =
IntervalMapImpl::BranchNode<KeyT, ValT, RootBranchCap, Traits>;
// When branched, we store a global start key as well as the branch node.
struct RootBranchData {
KeyT start;
RootBranch node;
};
public:
using Allocator = typename Sizer::Allocator;
using KeyType = KeyT;
using ValueType = ValT;
using KeyTraits = Traits;
private:
// The root data is either a RootLeaf or a RootBranchData instance.
LLVM_ALIGNAS(RootLeaf) LLVM_ALIGNAS(RootBranchData)
AlignedCharArrayUnion<RootLeaf, RootBranchData> data;
// Tree height.
// 0: Leaves in root.
// 1: Root points to leaf.
// 2: root->branch->leaf ...
unsigned height;
// Number of entries in the root node.
unsigned rootSize;
// Allocator used for creating external nodes.
Allocator &allocator;
/// Represent data as a node type without breaking aliasing rules.
template <typename T>
T &dataAs() const {
return *bit_cast<T *>(const_cast<char *>(data.buffer));
}
const RootLeaf &rootLeaf() const {
assert(!branched() && "Cannot acces leaf data in branched root");
return dataAs<RootLeaf>();
}
RootLeaf &rootLeaf() {
assert(!branched() && "Cannot acces leaf data in branched root");
return dataAs<RootLeaf>();
}
RootBranchData &rootBranchData() const {
assert(branched() && "Cannot access branch data in non-branched root");
return dataAs<RootBranchData>();
}
RootBranchData &rootBranchData() {
assert(branched() && "Cannot access branch data in non-branched root");
return dataAs<RootBranchData>();
}
const RootBranch &rootBranch() const { return rootBranchData().node; }
RootBranch &rootBranch() { return rootBranchData().node; }
KeyT rootBranchStart() const { return rootBranchData().start; }
KeyT &rootBranchStart() { return rootBranchData().start; }
template <typename NodeT> NodeT *newNode() {
return new(allocator.template Allocate<NodeT>()) NodeT();
}
template <typename NodeT> void deleteNode(NodeT *P) {
P->~NodeT();
allocator.Deallocate(P);
}
IdxPair branchRoot(unsigned Position);
IdxPair splitRoot(unsigned Position);
void switchRootToBranch() {
rootLeaf().~RootLeaf();
height = 1;
new (&rootBranchData()) RootBranchData();
}
void switchRootToLeaf() {
rootBranchData().~RootBranchData();
height = 0;
new(&rootLeaf()) RootLeaf();
}
bool branched() const { return height > 0; }
ValT treeSafeLookup(KeyT x, ValT NotFound) const;
void visitNodes(void (IntervalMap::*f)(IntervalMapImpl::NodeRef,
unsigned Level));
void deleteNode(IntervalMapImpl::NodeRef Node, unsigned Level);
public:
explicit IntervalMap(Allocator &a) : height(0), rootSize(0), allocator(a) {
assert((uintptr_t(data.buffer) & (alignof(RootLeaf) - 1)) == 0 &&
"Insufficient alignment");
new(&rootLeaf()) RootLeaf();
}
~IntervalMap() {
clear();
rootLeaf().~RootLeaf();
}
/// empty - Return true when no intervals are mapped.
bool empty() const {
return rootSize == 0;
}
/// start - Return the smallest mapped key in a non-empty map.
KeyT start() const {
assert(!empty() && "Empty IntervalMap has no start");
return !branched() ? rootLeaf().start(0) : rootBranchStart();
}
/// stop - Return the largest mapped key in a non-empty map.
KeyT stop() const {
assert(!empty() && "Empty IntervalMap has no stop");
return !branched() ? rootLeaf().stop(rootSize - 1) :
rootBranch().stop(rootSize - 1);
}
/// lookup - Return the mapped value at x or NotFound.
ValT lookup(KeyT x, ValT NotFound = ValT()) const {
if (empty() || Traits::startLess(x, start()) || Traits::stopLess(stop(), x))
return NotFound;
return branched() ? treeSafeLookup(x, NotFound) :
rootLeaf().safeLookup(x, NotFound);
}
/// insert - Add a mapping of [a;b] to y, coalesce with adjacent intervals.
/// It is assumed that no key in the interval is mapped to another value, but
/// overlapping intervals already mapped to y will be coalesced.
void insert(KeyT a, KeyT b, ValT y) {
if (branched() || rootSize == RootLeaf::Capacity)
return find(a).insert(a, b, y);
// Easy insert into root leaf.
unsigned p = rootLeaf().findFrom(0, rootSize, a);
rootSize = rootLeaf().insertFrom(p, rootSize, a, b, y);
}
/// clear - Remove all entries.
void clear();
class const_iterator;
class iterator;
friend class const_iterator;
friend class iterator;
const_iterator begin() const {
const_iterator I(*this);
I.goToBegin();
return I;
}
iterator begin() {
iterator I(*this);
I.goToBegin();
return I;
}
const_iterator end() const {
const_iterator I(*this);
I.goToEnd();
return I;
}
iterator end() {
iterator I(*this);
I.goToEnd();
return I;
}
/// find - Return an iterator pointing to the first interval ending at or
/// after x, or end().
const_iterator find(KeyT x) const {
const_iterator I(*this);
I.find(x);
return I;
}
iterator find(KeyT x) {
iterator I(*this);
I.find(x);
return I;
}
/// overlaps(a, b) - Return true if the intervals in this map overlap with the
/// interval [a;b].
bool overlaps(KeyT a, KeyT b) {
assert(Traits::nonEmpty(a, b));
const_iterator I = find(a);
if (!I.valid())
return false;
// [a;b] and [x;y] overlap iff x<=b and a<=y. The find() call guarantees the
// second part (y = find(a).stop()), so it is sufficient to check the first
// one.
return !Traits::stopLess(b, I.start());
}
};
/// treeSafeLookup - Return the mapped value at x or NotFound, assuming a
/// branched root.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
ValT IntervalMap<KeyT, ValT, N, Traits>::
treeSafeLookup(KeyT x, ValT NotFound) const {
assert(branched() && "treeLookup assumes a branched root");
IntervalMapImpl::NodeRef NR = rootBranch().safeLookup(x);
for (unsigned h = height-1; h; --h)
NR = NR.get<Branch>().safeLookup(x);
return NR.get<Leaf>().safeLookup(x, NotFound);
}
// branchRoot - Switch from a leaf root to a branched root.
// Return the new (root offset, node offset) corresponding to Position.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
IntervalMapImpl::IdxPair IntervalMap<KeyT, ValT, N, Traits>::
branchRoot(unsigned Position) {
using namespace IntervalMapImpl;
// How many external leaf nodes to hold RootLeaf+1?
const unsigned Nodes = RootLeaf::Capacity / Leaf::Capacity + 1;
// Compute element distribution among new nodes.
unsigned size[Nodes];
IdxPair NewOffset(0, Position);
// Is is very common for the root node to be smaller than external nodes.
if (Nodes == 1)
size[0] = rootSize;
else
NewOffset = distribute(Nodes, rootSize, Leaf::Capacity, nullptr, size,
Position, true);
// Allocate new nodes.
unsigned pos = 0;
NodeRef node[Nodes];
for (unsigned n = 0; n != Nodes; ++n) {
Leaf *L = newNode<Leaf>();
L->copy(rootLeaf(), pos, 0, size[n]);
node[n] = NodeRef(L, size[n]);
pos += size[n];
}
// Destroy the old leaf node, construct branch node instead.
switchRootToBranch();
for (unsigned n = 0; n != Nodes; ++n) {
rootBranch().stop(n) = node[n].template get<Leaf>().stop(size[n]-1);
rootBranch().subtree(n) = node[n];
}
rootBranchStart() = node[0].template get<Leaf>().start(0);
rootSize = Nodes;
return NewOffset;
}
// splitRoot - Split the current BranchRoot into multiple Branch nodes.
// Return the new (root offset, node offset) corresponding to Position.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
IntervalMapImpl::IdxPair IntervalMap<KeyT, ValT, N, Traits>::
splitRoot(unsigned Position) {
using namespace IntervalMapImpl;
// How many external leaf nodes to hold RootBranch+1?
const unsigned Nodes = RootBranch::Capacity / Branch::Capacity + 1;
// Compute element distribution among new nodes.
unsigned Size[Nodes];
IdxPair NewOffset(0, Position);
// Is is very common for the root node to be smaller than external nodes.
if (Nodes == 1)
Size[0] = rootSize;
else
NewOffset = distribute(Nodes, rootSize, Leaf::Capacity, nullptr, Size,
Position, true);
// Allocate new nodes.
unsigned Pos = 0;
NodeRef Node[Nodes];
for (unsigned n = 0; n != Nodes; ++n) {
Branch *B = newNode<Branch>();
B->copy(rootBranch(), Pos, 0, Size[n]);
Node[n] = NodeRef(B, Size[n]);
Pos += Size[n];
}
for (unsigned n = 0; n != Nodes; ++n) {
rootBranch().stop(n) = Node[n].template get<Branch>().stop(Size[n]-1);
rootBranch().subtree(n) = Node[n];
}
rootSize = Nodes;
++height;
return NewOffset;
}
/// visitNodes - Visit each external node.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
visitNodes(void (IntervalMap::*f)(IntervalMapImpl::NodeRef, unsigned Height)) {
if (!branched())
return;
SmallVector<IntervalMapImpl::NodeRef, 4> Refs, NextRefs;
// Collect level 0 nodes from the root.
for (unsigned i = 0; i != rootSize; ++i)
Refs.push_back(rootBranch().subtree(i));
// Visit all branch nodes.
for (unsigned h = height - 1; h; --h) {
for (unsigned i = 0, e = Refs.size(); i != e; ++i) {
for (unsigned j = 0, s = Refs[i].size(); j != s; ++j)
NextRefs.push_back(Refs[i].subtree(j));
(this->*f)(Refs[i], h);
}
Refs.clear();
Refs.swap(NextRefs);
}
// Visit all leaf nodes.
for (unsigned i = 0, e = Refs.size(); i != e; ++i)
(this->*f)(Refs[i], 0);
}
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
deleteNode(IntervalMapImpl::NodeRef Node, unsigned Level) {
if (Level)
deleteNode(&Node.get<Branch>());
else
deleteNode(&Node.get<Leaf>());
}
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
clear() {
if (branched()) {
visitNodes(&IntervalMap::deleteNode);
switchRootToLeaf();
}
rootSize = 0;
}
//===----------------------------------------------------------------------===//
//--- IntervalMap::const_iterator ----//
//===----------------------------------------------------------------------===//
template <typename KeyT, typename ValT, unsigned N, typename Traits>
class IntervalMap<KeyT, ValT, N, Traits>::const_iterator :
public std::iterator<std::bidirectional_iterator_tag, ValT> {
protected:
friend class IntervalMap;
// The map referred to.
IntervalMap *map = nullptr;
// We store a full path from the root to the current position.
// The path may be partially filled, but never between iterator calls.
IntervalMapImpl::Path path;
explicit const_iterator(const IntervalMap &map) :
map(const_cast<IntervalMap*>(&map)) {}
bool branched() const {
assert(map && "Invalid iterator");
return map->branched();
}
void setRoot(unsigned Offset) {
if (branched())
path.setRoot(&map->rootBranch(), map->rootSize, Offset);
else
path.setRoot(&map->rootLeaf(), map->rootSize, Offset);
}
void pathFillFind(KeyT x);
void treeFind(KeyT x);
void treeAdvanceTo(KeyT x);
/// unsafeStart - Writable access to start() for iterator.
KeyT &unsafeStart() const {
assert(valid() && "Cannot access invalid iterator");
return branched() ? path.leaf<Leaf>().start(path.leafOffset()) :
path.leaf<RootLeaf>().start(path.leafOffset());
}
/// unsafeStop - Writable access to stop() for iterator.
KeyT &unsafeStop() const {
assert(valid() && "Cannot access invalid iterator");
return branched() ? path.leaf<Leaf>().stop(path.leafOffset()) :
path.leaf<RootLeaf>().stop(path.leafOffset());
}
/// unsafeValue - Writable access to value() for iterator.
ValT &unsafeValue() const {
assert(valid() && "Cannot access invalid iterator");
return branched() ? path.leaf<Leaf>().value(path.leafOffset()) :
path.leaf<RootLeaf>().value(path.leafOffset());
}
public:
/// const_iterator - Create an iterator that isn't pointing anywhere.
const_iterator() = default;
/// setMap - Change the map iterated over. This call must be followed by a
/// call to goToBegin(), goToEnd(), or find()
void setMap(const IntervalMap &m) { map = const_cast<IntervalMap*>(&m); }
/// valid - Return true if the current position is valid, false for end().
bool valid() const { return path.valid(); }
/// atBegin - Return true if the current position is the first map entry.
bool atBegin() const { return path.atBegin(); }
/// start - Return the beginning of the current interval.
const KeyT &start() const { return unsafeStart(); }
/// stop - Return the end of the current interval.
const KeyT &stop() const { return unsafeStop(); }
/// value - Return the mapped value at the current interval.
const ValT &value() const { return unsafeValue(); }
const ValT &operator*() const { return value(); }
bool operator==(const const_iterator &RHS) const {
assert(map == RHS.map && "Cannot compare iterators from different maps");
if (!valid())
return !RHS.valid();
if (path.leafOffset() != RHS.path.leafOffset())
return false;
return &path.template leaf<Leaf>() == &RHS.path.template leaf<Leaf>();
}
bool operator!=(const const_iterator &RHS) const {
return !operator==(RHS);
}
/// goToBegin - Move to the first interval in map.
void goToBegin() {
setRoot(0);
if (branched())
path.fillLeft(map->height);
}
/// goToEnd - Move beyond the last interval in map.
void goToEnd() {
setRoot(map->rootSize);
}
/// preincrement - move to the next interval.
const_iterator &operator++() {
assert(valid() && "Cannot increment end()");
if (++path.leafOffset() == path.leafSize() && branched())
path.moveRight(map->height);
return *this;
}
/// postincrement - Dont do that!
const_iterator operator++(int) {
const_iterator tmp = *this;
operator++();
return tmp;
}
/// predecrement - move to the previous interval.
const_iterator &operator--() {
if (path.leafOffset() && (valid() || !branched()))
--path.leafOffset();
else
path.moveLeft(map->height);
return *this;
}
/// postdecrement - Dont do that!
const_iterator operator--(int) {
const_iterator tmp = *this;
operator--();
return tmp;
}
/// find - Move to the first interval with stop >= x, or end().
/// This is a full search from the root, the current position is ignored.
void find(KeyT x) {
if (branched())
treeFind(x);
else
setRoot(map->rootLeaf().findFrom(0, map->rootSize, x));
}
/// advanceTo - Move to the first interval with stop >= x, or end().
/// The search is started from the current position, and no earlier positions
/// can be found. This is much faster than find() for small moves.
void advanceTo(KeyT x) {
if (!valid())
return;
if (branched())
treeAdvanceTo(x);
else
path.leafOffset() =
map->rootLeaf().findFrom(path.leafOffset(), map->rootSize, x);
}
};
/// pathFillFind - Complete path by searching for x.
/// @param x Key to search for.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::pathFillFind(KeyT x) {
IntervalMapImpl::NodeRef NR = path.subtree(path.height());
for (unsigned i = map->height - path.height() - 1; i; --i) {
unsigned p = NR.get<Branch>().safeFind(0, x);
path.push(NR, p);
NR = NR.subtree(p);
}
path.push(NR, NR.get<Leaf>().safeFind(0, x));
}
/// treeFind - Find in a branched tree.
/// @param x Key to search for.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::treeFind(KeyT x) {
setRoot(map->rootBranch().findFrom(0, map->rootSize, x));
if (valid())
pathFillFind(x);
}
/// treeAdvanceTo - Find position after the current one.
/// @param x Key to search for.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::treeAdvanceTo(KeyT x) {
// Can we stay on the same leaf node?
if (!Traits::stopLess(path.leaf<Leaf>().stop(path.leafSize() - 1), x)) {
path.leafOffset() = path.leaf<Leaf>().safeFind(path.leafOffset(), x);
return;
}
// Drop the current leaf.
path.pop();
// Search towards the root for a usable subtree.
if (path.height()) {
for (unsigned l = path.height() - 1; l; --l) {
if (!Traits::stopLess(path.node<Branch>(l).stop(path.offset(l)), x)) {
// The branch node at l+1 is usable
path.offset(l + 1) =
path.node<Branch>(l + 1).safeFind(path.offset(l + 1), x);
return pathFillFind(x);
}
path.pop();
}
// Is the level-1 Branch usable?
if (!Traits::stopLess(map->rootBranch().stop(path.offset(0)), x)) {
path.offset(1) = path.node<Branch>(1).safeFind(path.offset(1), x);
return pathFillFind(x);
}
}
// We reached the root.
setRoot(map->rootBranch().findFrom(path.offset(0), map->rootSize, x));
if (valid())
pathFillFind(x);
}
//===----------------------------------------------------------------------===//
//--- IntervalMap::iterator ----//
//===----------------------------------------------------------------------===//
template <typename KeyT, typename ValT, unsigned N, typename Traits>
class IntervalMap<KeyT, ValT, N, Traits>::iterator : public const_iterator {
friend class IntervalMap;
using IdxPair = IntervalMapImpl::IdxPair;
explicit iterator(IntervalMap &map) : const_iterator(map) {}
void setNodeStop(unsigned Level, KeyT Stop);
bool insertNode(unsigned Level, IntervalMapImpl::NodeRef Node, KeyT Stop);
template <typename NodeT> bool overflow(unsigned Level);
void treeInsert(KeyT a, KeyT b, ValT y);
void eraseNode(unsigned Level);
void treeErase(bool UpdateRoot = true);
bool canCoalesceLeft(KeyT Start, ValT x);
bool canCoalesceRight(KeyT Stop, ValT x);
public:
/// iterator - Create null iterator.
iterator() = default;
/// setStart - Move the start of the current interval.
/// This may cause coalescing with the previous interval.
/// @param a New start key, must not overlap the previous interval.
void setStart(KeyT a);
/// setStop - Move the end of the current interval.
/// This may cause coalescing with the following interval.
/// @param b New stop key, must not overlap the following interval.
void setStop(KeyT b);
/// setValue - Change the mapped value of the current interval.
/// This may cause coalescing with the previous and following intervals.
/// @param x New value.
void setValue(ValT x);
/// setStartUnchecked - Move the start of the current interval without
/// checking for coalescing or overlaps.
/// This should only be used when it is known that coalescing is not required.
/// @param a New start key.
void setStartUnchecked(KeyT a) { this->unsafeStart() = a; }
/// setStopUnchecked - Move the end of the current interval without checking
/// for coalescing or overlaps.
/// This should only be used when it is known that coalescing is not required.
/// @param b New stop key.
void setStopUnchecked(KeyT b) {
this->unsafeStop() = b;
// Update keys in branch nodes as well.
if (this->path.atLastEntry(this->path.height()))
setNodeStop(this->path.height(), b);
}
/// setValueUnchecked - Change the mapped value of the current interval
/// without checking for coalescing.
/// @param x New value.
void setValueUnchecked(ValT x) { this->unsafeValue() = x; }
/// insert - Insert mapping [a;b] -> y before the current position.
void insert(KeyT a, KeyT b, ValT y);
/// erase - Erase the current interval.
void erase();
iterator &operator++() {
const_iterator::operator++();
return *this;
}
iterator operator++(int) {
iterator tmp = *this;
operator++();
return tmp;
}
iterator &operator--() {
const_iterator::operator--();
return *this;
}
iterator operator--(int) {
iterator tmp = *this;
operator--();
return tmp;
}
};
/// canCoalesceLeft - Can the current interval coalesce to the left after
/// changing start or value?
/// @param Start New start of current interval.
/// @param Value New value for current interval.
/// @return True when updating the current interval would enable coalescing.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
bool IntervalMap<KeyT, ValT, N, Traits>::
iterator::canCoalesceLeft(KeyT Start, ValT Value) {
using namespace IntervalMapImpl;
Path &P = this->path;
if (!this->branched()) {
unsigned i = P.leafOffset();
RootLeaf &Node = P.leaf<RootLeaf>();
return i && Node.value(i-1) == Value &&
Traits::adjacent(Node.stop(i-1), Start);
}
// Branched.
if (unsigned i = P.leafOffset()) {
Leaf &Node = P.leaf<Leaf>();
return Node.value(i-1) == Value && Traits::adjacent(Node.stop(i-1), Start);
} else if (NodeRef NR = P.getLeftSibling(P.height())) {
unsigned i = NR.size() - 1;
Leaf &Node = NR.get<Leaf>();
return Node.value(i) == Value && Traits::adjacent(Node.stop(i), Start);
}
return false;
}
/// canCoalesceRight - Can the current interval coalesce to the right after
/// changing stop or value?
/// @param Stop New stop of current interval.
/// @param Value New value for current interval.
/// @return True when updating the current interval would enable coalescing.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
bool IntervalMap<KeyT, ValT, N, Traits>::
iterator::canCoalesceRight(KeyT Stop, ValT Value) {
using namespace IntervalMapImpl;
Path &P = this->path;
unsigned i = P.leafOffset() + 1;
if (!this->branched()) {
if (i >= P.leafSize())
return false;
RootLeaf &Node = P.leaf<RootLeaf>();
return Node.value(i) == Value && Traits::adjacent(Stop, Node.start(i));
}
// Branched.
if (i < P.leafSize()) {
Leaf &Node = P.leaf<Leaf>();
return Node.value(i) == Value && Traits::adjacent(Stop, Node.start(i));
} else if (NodeRef NR = P.getRightSibling(P.height())) {
Leaf &Node = NR.get<Leaf>();
return Node.value(0) == Value && Traits::adjacent(Stop, Node.start(0));
}
return false;
}
/// setNodeStop - Update the stop key of the current node at level and above.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::setNodeStop(unsigned Level, KeyT Stop) {
// There are no references to the root node, so nothing to update.
if (!Level)
return;
IntervalMapImpl::Path &P = this->path;
// Update nodes pointing to the current node.
while (--Level) {
P.node<Branch>(Level).stop(P.offset(Level)) = Stop;
if (!P.atLastEntry(Level))
return;
}
// Update root separately since it has a different layout.
P.node<RootBranch>(Level).stop(P.offset(Level)) = Stop;
}
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::setStart(KeyT a) {
assert(Traits::nonEmpty(a, this->stop()) && "Cannot move start beyond stop");
KeyT &CurStart = this->unsafeStart();
if (!Traits::startLess(a, CurStart) || !canCoalesceLeft(a, this->value())) {
CurStart = a;
return;
}
// Coalesce with the interval to the left.
--*this;
a = this->start();
erase();
setStartUnchecked(a);
}
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::setStop(KeyT b) {
assert(Traits::nonEmpty(this->start(), b) && "Cannot move stop beyond start");
if (Traits::startLess(b, this->stop()) ||
!canCoalesceRight(b, this->value())) {
setStopUnchecked(b);
return;
}
// Coalesce with interval to the right.
KeyT a = this->start();
erase();
setStartUnchecked(a);
}
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::setValue(ValT x) {
setValueUnchecked(x);
if (canCoalesceRight(this->stop(), x)) {
KeyT a = this->start();
erase();
setStartUnchecked(a);
}
if (canCoalesceLeft(this->start(), x)) {
--*this;
KeyT a = this->start();
erase();
setStartUnchecked(a);
}
}
/// insertNode - insert a node before the current path at level.
/// Leave the current path pointing at the new node.
/// @param Level path index of the node to be inserted.
/// @param Node The node to be inserted.
/// @param Stop The last index in the new node.
/// @return True if the tree height was increased.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
bool IntervalMap<KeyT, ValT, N, Traits>::
iterator::insertNode(unsigned Level, IntervalMapImpl::NodeRef Node, KeyT Stop) {
assert(Level && "Cannot insert next to the root");
bool SplitRoot = false;
IntervalMap &IM = *this->map;
IntervalMapImpl::Path &P = this->path;
if (Level == 1) {
// Insert into the root branch node.
if (IM.rootSize < RootBranch::Capacity) {
IM.rootBranch().insert(P.offset(0), IM.rootSize, Node, Stop);
P.setSize(0, ++IM.rootSize);
P.reset(Level);
return SplitRoot;
}
// We need to split the root while keeping our position.
SplitRoot = true;
IdxPair Offset = IM.splitRoot(P.offset(0));
P.replaceRoot(&IM.rootBranch(), IM.rootSize, Offset);
// Fall through to insert at the new higher level.
++Level;
}
// When inserting before end(), make sure we have a valid path.
P.legalizeForInsert(--Level);
// Insert into the branch node at Level-1.
if (P.size(Level) == Branch::Capacity) {
// Branch node is full, handle handle the overflow.
assert(!SplitRoot && "Cannot overflow after splitting the root");
SplitRoot = overflow<Branch>(Level);
Level += SplitRoot;
}
P.node<Branch>(Level).insert(P.offset(Level), P.size(Level), Node, Stop);
P.setSize(Level, P.size(Level) + 1);
if (P.atLastEntry(Level))
setNodeStop(Level, Stop);
P.reset(Level + 1);
return SplitRoot;
}
// insert
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::insert(KeyT a, KeyT b, ValT y) {
if (this->branched())
return treeInsert(a, b, y);
IntervalMap &IM = *this->map;
IntervalMapImpl::Path &P = this->path;
// Try simple root leaf insert.
unsigned Size = IM.rootLeaf().insertFrom(P.leafOffset(), IM.rootSize, a, b, y);
// Was the root node insert successful?
if (Size <= RootLeaf::Capacity) {
P.setSize(0, IM.rootSize = Size);
return;
}
// Root leaf node is full, we must branch.
IdxPair Offset = IM.branchRoot(P.leafOffset());
P.replaceRoot(&IM.rootBranch(), IM.rootSize, Offset);
// Now it fits in the new leaf.
treeInsert(a, b, y);
}
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::treeInsert(KeyT a, KeyT b, ValT y) {
using namespace IntervalMapImpl;
Path &P = this->path;
if (!P.valid())
P.legalizeForInsert(this->map->height);
// Check if this insertion will extend the node to the left.
if (P.leafOffset() == 0 && Traits::startLess(a, P.leaf<Leaf>().start(0))) {
// Node is growing to the left, will it affect a left sibling node?
if (NodeRef Sib = P.getLeftSibling(P.height())) {
Leaf &SibLeaf = Sib.get<Leaf>();
unsigned SibOfs = Sib.size() - 1;
if (SibLeaf.value(SibOfs) == y &&
Traits::adjacent(SibLeaf.stop(SibOfs), a)) {
// This insertion will coalesce with the last entry in SibLeaf. We can
// handle it in two ways:
// 1. Extend SibLeaf.stop to b and be done, or
// 2. Extend a to SibLeaf, erase the SibLeaf entry and continue.
// We prefer 1., but need 2 when coalescing to the right as well.
Leaf &CurLeaf = P.leaf<Leaf>();
P.moveLeft(P.height());
if (Traits::stopLess(b, CurLeaf.start(0)) &&
(y != CurLeaf.value(0) || !Traits::adjacent(b, CurLeaf.start(0)))) {
// Easy, just extend SibLeaf and we're done.
setNodeStop(P.height(), SibLeaf.stop(SibOfs) = b);
return;
} else {
// We have both left and right coalescing. Erase the old SibLeaf entry
// and continue inserting the larger interval.
a = SibLeaf.start(SibOfs);
treeErase(/* UpdateRoot= */false);
}
}
} else {
// No left sibling means we are at begin(). Update cached bound.
this->map->rootBranchStart() = a;
}
}
// When we are inserting at the end of a leaf node, we must update stops.
unsigned Size = P.leafSize();
bool Grow = P.leafOffset() == Size;
Size = P.leaf<Leaf>().insertFrom(P.leafOffset(), Size, a, b, y);
// Leaf insertion unsuccessful? Overflow and try again.
if (Size > Leaf::Capacity) {
overflow<Leaf>(P.height());
Grow = P.leafOffset() == P.leafSize();
Size = P.leaf<Leaf>().insertFrom(P.leafOffset(), P.leafSize(), a, b, y);
assert(Size <= Leaf::Capacity && "overflow() didn't make room");
}
// Inserted, update offset and leaf size.
P.setSize(P.height(), Size);
// Insert was the last node entry, update stops.
if (Grow)
setNodeStop(P.height(), b);
}
/// erase - erase the current interval and move to the next position.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::erase() {
IntervalMap &IM = *this->map;
IntervalMapImpl::Path &P = this->path;
assert(P.valid() && "Cannot erase end()");
if (this->branched())
return treeErase();
IM.rootLeaf().erase(P.leafOffset(), IM.rootSize);
P.setSize(0, --IM.rootSize);
}
/// treeErase - erase() for a branched tree.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::treeErase(bool UpdateRoot) {
IntervalMap &IM = *this->map;
IntervalMapImpl::Path &P = this->path;
Leaf &Node = P.leaf<Leaf>();
// Nodes are not allowed to become empty.
if (P.leafSize() == 1) {
IM.deleteNode(&Node);
eraseNode(IM.height);
// Update rootBranchStart if we erased begin().
if (UpdateRoot && IM.branched() && P.valid() && P.atBegin())
IM.rootBranchStart() = P.leaf<Leaf>().start(0);
return;
}
// Erase current entry.
Node.erase(P.leafOffset(), P.leafSize());
unsigned NewSize = P.leafSize() - 1;
P.setSize(IM.height, NewSize);
// When we erase the last entry, update stop and move to a legal position.
if (P.leafOffset() == NewSize) {
setNodeStop(IM.height, Node.stop(NewSize - 1));
P.moveRight(IM.height);
} else if (UpdateRoot && P.atBegin())
IM.rootBranchStart() = P.leaf<Leaf>().start(0);
}
/// eraseNode - Erase the current node at Level from its parent and move path to
/// the first entry of the next sibling node.
/// The node must be deallocated by the caller.
/// @param Level 1..height, the root node cannot be erased.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::eraseNode(unsigned Level) {
assert(Level && "Cannot erase root node");
IntervalMap &IM = *this->map;
IntervalMapImpl::Path &P = this->path;
if (--Level == 0) {
IM.rootBranch().erase(P.offset(0), IM.rootSize);
P.setSize(0, --IM.rootSize);
// If this cleared the root, switch to height=0.
if (IM.empty()) {
IM.switchRootToLeaf();
this->setRoot(0);
return;
}
} else {
// Remove node ref from branch node at Level.
Branch &Parent = P.node<Branch>(Level);
if (P.size(Level) == 1) {
// Branch node became empty, remove it recursively.
IM.deleteNode(&Parent);
eraseNode(Level);
} else {
// Branch node won't become empty.
Parent.erase(P.offset(Level), P.size(Level));
unsigned NewSize = P.size(Level) - 1;
P.setSize(Level, NewSize);
// If we removed the last branch, update stop and move to a legal pos.
if (P.offset(Level) == NewSize) {
setNodeStop(Level, Parent.stop(NewSize - 1));
P.moveRight(Level);
}
}
}
// Update path cache for the new right sibling position.
if (P.valid()) {
P.reset(Level + 1);
P.offset(Level + 1) = 0;
}
}
/// overflow - Distribute entries of the current node evenly among
/// its siblings and ensure that the current node is not full.
/// This may require allocating a new node.
/// @tparam NodeT The type of node at Level (Leaf or Branch).
/// @param Level path index of the overflowing node.
/// @return True when the tree height was changed.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
template <typename NodeT>
bool IntervalMap<KeyT, ValT, N, Traits>::
iterator::overflow(unsigned Level) {
using namespace IntervalMapImpl;
Path &P = this->path;
unsigned CurSize[4];
NodeT *Node[4];
unsigned Nodes = 0;
unsigned Elements = 0;
unsigned Offset = P.offset(Level);
// Do we have a left sibling?
NodeRef LeftSib = P.getLeftSibling(Level);
if (LeftSib) {
Offset += Elements = CurSize[Nodes] = LeftSib.size();
Node[Nodes++] = &LeftSib.get<NodeT>();
}
// Current node.
Elements += CurSize[Nodes] = P.size(Level);
Node[Nodes++] = &P.node<NodeT>(Level);
// Do we have a right sibling?
NodeRef RightSib = P.getRightSibling(Level);
if (RightSib) {
Elements += CurSize[Nodes] = RightSib.size();
Node[Nodes++] = &RightSib.get<NodeT>();
}
// Do we need to allocate a new node?
unsigned NewNode = 0;
if (Elements + 1 > Nodes * NodeT::Capacity) {
// Insert NewNode at the penultimate position, or after a single node.
NewNode = Nodes == 1 ? 1 : Nodes - 1;
CurSize[Nodes] = CurSize[NewNode];
Node[Nodes] = Node[NewNode];
CurSize[NewNode] = 0;
Node[NewNode] = this->map->template newNode<NodeT>();
++Nodes;
}
// Compute the new element distribution.
unsigned NewSize[4];
IdxPair NewOffset = distribute(Nodes, Elements, NodeT::Capacity,
CurSize, NewSize, Offset, true);
adjustSiblingSizes(Node, Nodes, CurSize, NewSize);
// Move current location to the leftmost node.
if (LeftSib)
P.moveLeft(Level);
// Elements have been rearranged, now update node sizes and stops.
bool SplitRoot = false;
unsigned Pos = 0;
while (true) {
KeyT Stop = Node[Pos]->stop(NewSize[Pos]-1);
if (NewNode && Pos == NewNode) {
SplitRoot = insertNode(Level, NodeRef(Node[Pos], NewSize[Pos]), Stop);
Level += SplitRoot;
} else {
P.setSize(Level, NewSize[Pos]);
setNodeStop(Level, Stop);
}
if (Pos + 1 == Nodes)
break;
P.moveRight(Level);
++Pos;
}
// Where was I? Find NewOffset.
while(Pos != NewOffset.first) {
P.moveLeft(Level);
--Pos;
}
P.offset(Level) = NewOffset.second;
return SplitRoot;
}
//===----------------------------------------------------------------------===//
//--- IntervalMapOverlaps ----//
//===----------------------------------------------------------------------===//
/// IntervalMapOverlaps - Iterate over the overlaps of mapped intervals in two
/// IntervalMaps. The maps may be different, but the KeyT and Traits types
/// should be the same.
///
/// Typical uses:
///
/// 1. Test for overlap:
/// bool overlap = IntervalMapOverlaps(a, b).valid();
///
/// 2. Enumerate overlaps:
/// for (IntervalMapOverlaps I(a, b); I.valid() ; ++I) { ... }
///
template <typename MapA, typename MapB>
class IntervalMapOverlaps {
using KeyType = typename MapA::KeyType;
using Traits = typename MapA::KeyTraits;
typename MapA::const_iterator posA;
typename MapB::const_iterator posB;
/// advance - Move posA and posB forward until reaching an overlap, or until
/// either meets end.
/// Don't move the iterators if they are already overlapping.
void advance() {
if (!valid())
return;
if (Traits::stopLess(posA.stop(), posB.start())) {
// A ends before B begins. Catch up.
posA.advanceTo(posB.start());
if (!posA.valid() || !Traits::stopLess(posB.stop(), posA.start()))
return;
} else if (Traits::stopLess(posB.stop(), posA.start())) {
// B ends before A begins. Catch up.
posB.advanceTo(posA.start());
if (!posB.valid() || !Traits::stopLess(posA.stop(), posB.start()))
return;
} else
// Already overlapping.
return;
while (true) {
// Make a.end > b.start.
posA.advanceTo(posB.start());
if (!posA.valid() || !Traits::stopLess(posB.stop(), posA.start()))
return;
// Make b.end > a.start.
posB.advanceTo(posA.start());
if (!posB.valid() || !Traits::stopLess(posA.stop(), posB.start()))
return;
}
}
public:
/// IntervalMapOverlaps - Create an iterator for the overlaps of a and b.
IntervalMapOverlaps(const MapA &a, const MapB &b)
: posA(b.empty() ? a.end() : a.find(b.start())),
posB(posA.valid() ? b.find(posA.start()) : b.end()) { advance(); }
/// valid - Return true if iterator is at an overlap.
bool valid() const {
return posA.valid() && posB.valid();
}
/// a - access the left hand side in the overlap.
const typename MapA::const_iterator &a() const { return posA; }
/// b - access the right hand side in the overlap.
const typename MapB::const_iterator &b() const { return posB; }
/// start - Beginning of the overlapping interval.
KeyType start() const {
KeyType ak = a().start();
KeyType bk = b().start();
return Traits::startLess(ak, bk) ? bk : ak;
}
/// stop - End of the overlapping interval.
KeyType stop() const {
KeyType ak = a().stop();
KeyType bk = b().stop();
return Traits::startLess(ak, bk) ? ak : bk;
}
/// skipA - Move to the next overlap that doesn't involve a().
void skipA() {
++posA;
advance();
}
/// skipB - Move to the next overlap that doesn't involve b().
void skipB() {
++posB;
advance();
}
/// Preincrement - Move to the next overlap.
IntervalMapOverlaps &operator++() {
// Bump the iterator that ends first. The other one may have more overlaps.
if (Traits::startLess(posB.stop(), posA.stop()))
skipB();
else
skipA();
return *this;
}
/// advanceTo - Move to the first overlapping interval with
/// stopLess(x, stop()).
void advanceTo(KeyType x) {
if (!valid())
return;
// Make sure advanceTo sees monotonic keys.
if (Traits::stopLess(posA.stop(), x))
posA.advanceTo(x);
if (Traits::stopLess(posB.stop(), x))
posB.advanceTo(x);
advance();
}
};
} // end namespace llvm
#endif // LLVM_ADT_INTERVALMAP_H
Reference in New Issue View Git Blame Copy Permalink