llvm-6502/include/llvm/ADT/IntervalMap.h
Jakob Stoklund Olesen 487a5b786f Fix old GCC build error.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119884 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-20 01:24:43 +00:00

1731 lines
58 KiB
C++

//===- llvm/ADT/IntervalMap.h - A sorted interval map -----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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/SmallVector.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/RecyclingAllocator.h"
#include <limits>
#include <iterator>
// FIXME: Remove debugging code.
#include "llvm/Support/raw_ostream.h"
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;
}
};
/// IntervalMapImpl - Namespace used for IntervalMap implementation details.
/// It should be considered private to the implementation.
namespace IntervalMapImpl {
// Forward declarations.
template <typename, typename, unsigned, typename> class LeafNode;
template <typename, typename, unsigned, typename> class BranchNode;
typedef std::pair<unsigned,unsigned> IdxPair;
//===----------------------------------------------------------------------===//
//--- Node Storage ---//
//===----------------------------------------------------------------------===//
//
// 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");
std::copy(Other.first + i, Other.first + i + Count, first + j);
std::copy(Other.second + i, Other.second + i + Count, second + j);
}
/// 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");
std::copy_backward(first + i, first + i + Count, first + j + Count);
std::copy_backward(second + i, second + i + Count, second + j + 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);
}
/// 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;
}
}
};
//===----------------------------------------------------------------------===//
//--- 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
};
typedef NodeBase<std::pair<KeyT, KeyT>, ValT, LeafSize> LeafBase;
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.
typedef RecyclingAllocator<BumpPtrAllocator, char,
AllocBytes, CacheLineBytes> Allocator;
};
//===----------------------------------------------------------------------===//
//--- 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.
//
//===----------------------------------------------------------------------===//
struct CacheAlignedPointerTraits {
static inline void *getAsVoidPointer(void *P) { return P; }
static inline void *getFromVoidPointer(void *P) { return P; }
enum { NumLowBitsAvailable = Log2CacheLine };
};
class NodeRef {
PointerIntPair<void*, Log2CacheLine, unsigned, CacheAlignedPointerTraits> pip;
public:
/// NodeRef - Create a null ref.
NodeRef() {}
/// operator bool - Detect a null ref.
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) {
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);
}
};
//===----------------------------------------------------------------------===//
//--- Leaf nodes ---//
//===----------------------------------------------------------------------===//
//
// 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);
}
IdxPair insertFrom(unsigned i, unsigned Size, KeyT a, KeyT b, ValT y);
unsigned extendStop(unsigned i, unsigned Size, KeyT b);
#ifndef NDEBUG
void dump(unsigned Size) {
errs() << " N" << this << " [shape=record label=\"{ " << Size << '/' << N;
for (unsigned i = 0; i != Size; ++i)
errs() << " | {" << start(i) << '-' << stop(i) << "|" << value(i) << '}';
errs() << "}\"];\n";
}
#endif
};
/// 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 i 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>
IdxPair LeafNode<KeyT, ValT, N, Traits>::
insertFrom(unsigned i, unsigned Size, KeyT a, KeyT b, ValT y) {
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)));
// Coalesce with previous interval.
if (i && value(i - 1) == y && Traits::adjacent(stop(i - 1), a))
return IdxPair(i - 1, extendStop(i - 1, Size, b));
// Detect overflow.
if (i == N)
return IdxPair(i, N + 1);
// Add new interval at end.
if (i == Size) {
start(i) = a;
stop(i) = b;
value(i) = y;
return IdxPair(i, Size + 1);
}
// Overlapping intervals?
if (!Traits::stopLess(b, start(i))) {
assert(value(i) == y && "Inconsistent values in overlapping intervals");
if (Traits::startLess(a, start(i)))
start(i) = a;
return IdxPair(i, extendStop(i, Size, b));
}
// Try to coalesce with following interval.
if (value(i) == y && Traits::adjacent(b, start(i))) {
start(i) = a;
return IdxPair(i, Size);
}
// We must insert before i. Detect overflow.
if (Size == N)
return IdxPair(i, N + 1);
// Insert before i.
this->shift(i, Size);
start(i) = a;
stop(i) = b;
value(i) = y;
return IdxPair(i, Size + 1);
}
/// extendStop - Extend stop(i) to b, coalescing with following intervals.
/// @param i Interval to extend.
/// @param Size Number of elements in node.
/// @param b New interval end point.
/// @return New node size after coalescing.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
unsigned LeafNode<KeyT, ValT, N, Traits>::
extendStop(unsigned i, unsigned Size, KeyT b) {
assert(i < Size && Size <= N && "Bad indices");
// Are we even extending the interval?
if (Traits::startLess(b, stop(i)))
return Size;
// Find the first interval that may be preserved.
unsigned j = findFrom(i + 1, Size, b);
if (j < Size) {
// Would key[i] overlap key[j] after the extension?
if (Traits::stopLess(b, start(j))) {
// Not overlapping. Perhaps adjacent and coalescable?
if (value(i) == value(j) && Traits::adjacent(b, start(j)))
b = stop(j++);
} else {
// Overlap. Include key[j] in the new interval.
assert(value(i) == value(j) && "Overlapping values");
b = stop(j++);
}
}
stop(i) = b;
// Entries [i+1;j) were coalesced.
if (i + 1 < j && j < Size)
this->erase(i + 1, j, Size);
return Size - (j - (i + 1));
}
//===----------------------------------------------------------------------===//
//--- Branch nodes ---//
//===----------------------------------------------------------------------===//
//
// 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;
}
#ifndef NDEBUG
void dump(unsigned Size) {
errs() << " N" << this << " [shape=record label=\"" << Size << '/' << N;
for (unsigned i = 0; i != Size; ++i)
errs() << " | <s" << i << "> " << stop(i);
errs() << "\"];\n";
for (unsigned i = 0; i != Size; ++i)
errs() << " N" << this << ":s" << i << " -> N"
<< &subtree(i).template get<BranchNode>() << ";\n";
}
#endif
};
} // namespace IntervalMapImpl
//===----------------------------------------------------------------------===//
//--- IntervalMap ----//
//===----------------------------------------------------------------------===//
template <typename KeyT, typename ValT,
unsigned N = IntervalMapImpl::NodeSizer<KeyT, ValT>::LeafSize,
typename Traits = IntervalMapInfo<KeyT> >
class IntervalMap {
typedef IntervalMapImpl::NodeSizer<KeyT, ValT> Sizer;
typedef IntervalMapImpl::LeafNode<KeyT, ValT, Sizer::LeafSize, Traits> Leaf;
typedef IntervalMapImpl::BranchNode<KeyT, ValT, Sizer::BranchSize, Traits>
Branch;
typedef IntervalMapImpl::LeafNode<KeyT, ValT, N, Traits> RootLeaf;
typedef IntervalMapImpl::IdxPair 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
};
typedef IntervalMapImpl::BranchNode<KeyT, ValT, RootBranchCap, Traits>
RootBranch;
// When branched, we store a global start key as well as the branch node.
struct RootBranchData {
KeyT start;
RootBranch node;
};
enum {
RootDataSize = sizeof(RootBranchData) > sizeof(RootLeaf) ?
sizeof(RootBranchData) : sizeof(RootLeaf)
};
public:
typedef typename Sizer::Allocator Allocator;
private:
// The root data is either a RootLeaf or a RootBranchData instance.
// We can't put them in a union since C++03 doesn't allow non-trivial
// constructors in unions.
// Instead, we use a char array with pointer alignment. The alignment is
// ensured by the allocator member in the class, but still verified in the
// constructor. We don't support keys or values that are more aligned than a
// pointer.
char data[RootDataSize];
// 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;
/// dataAs - Represent data as a node type without breaking aliasing rules.
template <typename T>
T &dataAs() const {
union {
const char *d;
T *t;
} u;
u.d = data;
return *u.t;
}
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; }
Leaf *allocLeaf() {
return new(allocator.template Allocate<Leaf>()) Leaf();
}
void deleteLeaf(Leaf *P) {
P->~Leaf();
allocator.Deallocate(P);
}
Branch *allocBranch() {
return new(allocator.template Allocate<Branch>()) Branch();
}
void deleteBranch(Branch *P) {
P->~Branch();
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) & (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) {
find(a).insert(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 {
iterator I(*this);
I.goToBegin();
return I;
}
iterator begin() {
iterator I(*this);
I.goToBegin();
return I;
}
const_iterator end() 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 {
iterator I(*this);
I.find(x);
return I;
}
iterator find(KeyT x) {
iterator I(*this);
I.find(x);
return I;
}
#ifndef NDEBUG
void dump();
void dumpNode(IntervalMapImpl::NodeRef Node, unsigned Height);
#endif
};
/// 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, NULL, size,
Position, true);
// Allocate new nodes.
unsigned pos = 0;
NodeRef node[Nodes];
for (unsigned n = 0; n != Nodes; ++n) {
node[n] = NodeRef(allocLeaf(), size[n]);
node[n].template get<Leaf>().copy(rootLeaf(), pos, 0, 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, NULL, Size,
Position, true);
// Allocate new nodes.
unsigned Pos = 0;
NodeRef Node[Nodes];
for (unsigned n = 0; n != Nodes; ++n) {
Node[n] = NodeRef(allocBranch(), Size[n]);
Node[n].template get<Branch>().copy(rootBranch(), Pos, 0, 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;
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)
deleteBranch(&Node.get<Branch>());
else
deleteLeaf(&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;
}
#ifndef NDEBUG
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
dumpNode(IntervalMapImpl::NodeRef Node, unsigned Height) {
if (Height)
Node.get<Branch>().dump(Node.size());
else
Node.get<Leaf>().dump(Node.size());
}
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
dump() {
errs() << "digraph {\n";
if (branched())
rootBranch().dump(rootSize);
else
rootLeaf().dump(rootSize);
visitNodes(&IntervalMap::dumpNode);
errs() << "}\n";
}
#endif
//===----------------------------------------------------------------------===//
//--- 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;
typedef std::pair<IntervalMapImpl::NodeRef, unsigned> PathEntry;
typedef SmallVector<PathEntry, 4> Path;
// The map referred to.
IntervalMap *map;
// The offset into map's root node.
unsigned rootOffset;
// We store a full path from the root to the current position.
//
// When rootOffset == map->rootSize, we are at end() and path() is empty.
// Otherwise, when branched these conditions hold:
//
// 1. path.front().first == rootBranch().subtree(rootOffset)
// 2. path[i].first == path[i-1].first.subtree(path[i-1].second)
// 3. path.size() == map->height.
//
// Thus, path.back() always refers to the current leaf node unless the root is
// unbranched.
//
// The path may be partially filled, but never between iterator calls.
Path path;
explicit const_iterator(IntervalMap &map)
: map(&map), rootOffset(map.rootSize) {}
bool branched() const {
assert(map && "Invalid iterator");
return map->branched();
}
IntervalMapImpl::NodeRef pathNode(unsigned h) const { return path[h].first; }
IntervalMapImpl::NodeRef &pathNode(unsigned h) { return path[h].first; }
unsigned pathOffset(unsigned h) const { return path[h].second; }
unsigned &pathOffset(unsigned h) { return path[h].second; }
Leaf &treeLeaf() const {
assert(branched() && path.size() == map->height);
return path.back().first.template get<Leaf>();
}
unsigned treeLeafSize() const {
assert(branched() && path.size() == map->height);
return path.back().first.size();
}
unsigned &treeLeafOffset() {
assert(branched() && path.size() == map->height);
return path.back().second;
}
unsigned treeLeafOffset() const {
assert(branched() && path.size() == map->height);
return path.back().second;
}
// Get the next node ptr for an incomplete path.
IntervalMapImpl::NodeRef pathNextDown() {
assert(path.size() < map->height && "Path is already complete");
if (path.empty())
return map->rootBranch().subtree(rootOffset);
else
return path.back().first.subtree(path.back().second);
}
void pathFillLeft();
void pathFillFind(KeyT x);
void pathFillRight();
IntervalMapImpl::NodeRef leftSibling(unsigned level) const;
IntervalMapImpl::NodeRef rightSibling(unsigned level) const;
void treeIncrement();
void treeDecrement();
void treeFind(KeyT x);
public:
/// valid - Return true if the current position is valid, false for end().
bool valid() const {
assert(map && "Invalid iterator");
return rootOffset < map->rootSize;
}
/// start - Return the beginning of the current interval.
const KeyT &start() const {
assert(valid() && "Cannot access invalid iterator");
return branched() ? treeLeaf().start(treeLeafOffset()) :
map->rootLeaf().start(rootOffset);
}
/// stop - Return the end of the current interval.
const KeyT &stop() const {
assert(valid() && "Cannot access invalid iterator");
return branched() ? treeLeaf().stop(treeLeafOffset()) :
map->rootLeaf().stop(rootOffset);
}
/// value - Return the mapped value at the current interval.
const ValT &value() const {
assert(valid() && "Cannot access invalid iterator");
return branched() ? treeLeaf().value(treeLeafOffset()) :
map->rootLeaf().value(rootOffset);
}
const ValT &operator*() const {
return value();
}
bool operator==(const const_iterator &RHS) const {
assert(map == RHS.map && "Cannot compare iterators from different maps");
return rootOffset == RHS.rootOffset &&
(!valid() || !branched() || path.back() == RHS.path.back());
}
bool operator!=(const const_iterator &RHS) const {
return !operator==(RHS);
}
/// goToBegin - Move to the first interval in map.
void goToBegin() {
rootOffset = 0;
path.clear();
if (branched())
pathFillLeft();
}
/// goToEnd - Move beyond the last interval in map.
void goToEnd() {
rootOffset = map->rootSize;
path.clear();
}
/// preincrement - move to the next interval.
const_iterator &operator++() {
assert(valid() && "Cannot increment end()");
if (!branched())
++rootOffset;
else if (treeLeafOffset() != treeLeafSize() - 1)
++treeLeafOffset();
else
treeIncrement();
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 (!branched()) {
assert(rootOffset && "Cannot decrement begin()");
--rootOffset;
} else if (valid() && treeLeafOffset())
--treeLeafOffset();
else
treeDecrement();
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
rootOffset = 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 (branched())
treeAdvanceTo(x);
else
rootOffset = map->rootLeaf().findFrom(rootOffset, map->rootSize, x);
}
};
// pathFillLeft - Complete path by following left-most branches.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::pathFillLeft() {
IntervalMapImpl::NodeRef NR = pathNextDown();
for (unsigned i = map->height - path.size() - 1; i; --i) {
path.push_back(PathEntry(NR, 0));
NR = NR.subtree(0);
}
path.push_back(PathEntry(NR, 0));
}
// pathFillFind - Complete path by searching for x.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::pathFillFind(KeyT x) {
IntervalMapImpl::NodeRef NR = pathNextDown();
for (unsigned i = map->height - path.size() - 1; i; --i) {
unsigned p = NR.get<Branch>().safeFind(0, x);
path.push_back(PathEntry(NR, p));
NR = NR.subtree(p);
}
path.push_back(PathEntry(NR, NR.get<Leaf>().safeFind(0, x)));
}
// pathFillRight - Complete path by adding rightmost entries.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::pathFillRight() {
IntervalMapImpl::NodeRef NR = pathNextDown();
for (unsigned i = map->height - path.size() - 1; i; --i) {
unsigned p = NR.size() - 1;
path.push_back(PathEntry(NR, p));
NR = NR.subtree(p);
}
path.push_back(PathEntry(NR, NR.size() - 1));
}
/// leftSibling - find the left sibling node to path[level].
/// @param level 0 is just below the root, map->height - 1 for the leaves.
/// @return The left sibling NodeRef, or NULL.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
IntervalMapImpl::NodeRef IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::leftSibling(unsigned level) const {
using namespace IntervalMapImpl;
assert(branched() && "Not at a branched node");
assert(level <= path.size() && "Bad level");
// Go up the tree until we can go left.
unsigned h = level;
while (h && pathOffset(h - 1) == 0)
--h;
// We are at the first leaf node, no left sibling.
if (!h && rootOffset == 0)
return NodeRef();
// NR is the subtree containing our left sibling.
NodeRef NR = h ?
pathNode(h - 1).subtree(pathOffset(h - 1) - 1) :
map->rootBranch().subtree(rootOffset - 1);
// Keep right all the way down.
for (; h != level; ++h)
NR = NR.subtree(NR.size() - 1);
return NR;
}
/// rightSibling - find the right sibling node to path[level].
/// @param level 0 is just below the root, map->height - 1 for the leaves.
/// @return The right sibling NodeRef, or NULL.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
IntervalMapImpl::NodeRef IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::rightSibling(unsigned level) const {
using namespace IntervalMapImpl;
assert(branched() && "Not at a branched node");
assert(level <= this->path.size() && "Bad level");
// Go up the tree until we can go right.
unsigned h = level;
while (h && pathOffset(h - 1) == pathNode(h - 1).size() - 1)
--h;
// We are at the last leaf node, no right sibling.
if (!h && rootOffset == map->rootSize - 1)
return NodeRef();
// NR is the subtree containing our right sibling.
NodeRef NR = h ?
pathNode(h - 1).subtree(pathOffset(h - 1) + 1) :
map->rootBranch().subtree(rootOffset + 1);
// Keep left all the way down.
for (; h != level; ++h)
NR = NR.subtree(0);
return NR;
}
// treeIncrement - Move to the beginning of the next leaf node.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::treeIncrement() {
assert(branched() && "treeIncrement is not for small maps");
assert(path.size() == map->height && "inconsistent iterator");
do path.pop_back();
while (!path.empty() && path.back().second == path.back().first.size() - 1);
if (path.empty()) {
++rootOffset;
if (!valid())
return;
} else
++path.back().second;
pathFillLeft();
}
// treeDecrement - Move to the end of the previous leaf node.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::treeDecrement() {
assert(branched() && "treeDecrement is not for small maps");
if (valid()) {
assert(path.size() == map->height && "inconsistent iterator");
do path.pop_back();
while (!path.empty() && path.back().second == 0);
}
if (path.empty()) {
assert(rootOffset && "cannot treeDecrement() on begin()");
--rootOffset;
} else
--path.back().second;
pathFillRight();
}
// treeFind - Find in a branched tree.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
const_iterator::treeFind(KeyT x) {
path.clear();
rootOffset = map->rootBranch().findFrom(0, map->rootSize, x);
if (valid())
pathFillFind(x);
}
//===----------------------------------------------------------------------===//
//--- iterator ----//
//===----------------------------------------------------------------------===//
namespace 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);
}
template <typename KeyT, typename ValT, unsigned N, typename Traits>
class IntervalMap<KeyT, ValT, N, Traits>::iterator : public const_iterator {
friend class IntervalMap;
typedef IntervalMapImpl::IdxPair IdxPair;
explicit iterator(IntervalMap &map) : const_iterator(map) {}
void setNodeSize(unsigned Level, unsigned Size);
void setNodeStop(unsigned Level, KeyT Stop);
void insertNode(unsigned Level, IntervalMapImpl::NodeRef Node, KeyT Stop);
void overflowLeaf();
void treeInsert(KeyT a, KeyT b, ValT y);
public:
/// insert - Insert mapping [a;b] -> y before the current position.
void insert(KeyT a, KeyT b, ValT y);
};
/// setNodeSize - Set the size of the node at path[level], updating both path
/// and the real tree.
/// @param level 0 is just below the root, map->height - 1 for the leaves.
/// @param size New node size.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::setNodeSize(unsigned Level, unsigned Size) {
this->pathNode(Level).setSize(Size);
if (Level)
this->pathNode(Level-1).subtree(this->pathOffset(Level-1)).setSize(Size);
else
this->map->rootBranch().subtree(this->rootOffset).setSize(Size);
}
/// 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) {
while (Level--) {
this->pathNode(Level).template get<Branch>()
.stop(this->pathOffset(Level)) = Stop;
if (this->pathOffset(Level) != this->pathNode(Level).size() - 1)
return;
}
this->map->rootBranch().stop(this->rootOffset) = Stop;
}
/// insertNode - insert a node before the current path at level.
/// Leave the current path pointing at the new node.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::insertNode(unsigned Level, IntervalMapImpl::NodeRef Node, KeyT Stop) {
if (!Level) {
// Insert into the root branch node.
IntervalMap &IM = *this->map;
if (IM.rootSize < RootBranch::Capacity) {
IM.rootBranch().insert(this->rootOffset, IM.rootSize, Node, Stop);
++IM.rootSize;
return;
}
// We need to split the root while keeping our position.
IdxPair Offset = IM.splitRoot(this->rootOffset);
this->rootOffset = Offset.first;
this->path.insert(this->path.begin(),std::make_pair(
this->map->rootBranch().subtree(Offset.first), Offset.second));
Level = 1;
}
// When inserting before end(), make sure we have a valid path.
if (!this->valid()) {
this->treeDecrement();
++this->pathOffset(Level-1);
}
// Insert into the branch node at level-1.
IntervalMapImpl::NodeRef NR = this->pathNode(Level-1);
unsigned Offset = this->pathOffset(Level-1);
assert(NR.size() < Branch::Capacity && "Branch overflow");
NR.get<Branch>().insert(Offset, NR.size(), Node, Stop);
setNodeSize(Level - 1, NR.size() + 1);
}
// 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);
IdxPair IP = this->map->rootLeaf().insertFrom(this->rootOffset,
this->map->rootSize,
a, b, y);
if (IP.second <= RootLeaf::Capacity) {
this->rootOffset = IP.first;
this->map->rootSize = IP.second;
return;
}
IdxPair Offset = this->map->branchRoot(this->rootOffset);
this->rootOffset = Offset.first;
this->path.push_back(std::make_pair(
this->map->rootBranch().subtree(Offset.first), Offset.second));
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) {
if (!this->valid()) {
// end() has an empty path. Go back to the last leaf node and use an
// invalid offset instead.
this->treeDecrement();
++this->treeLeafOffset();
}
IdxPair IP = this->treeLeaf().insertFrom(this->treeLeafOffset(),
this->treeLeafSize(), a, b, y);
this->treeLeafOffset() = IP.first;
if (IP.second <= Leaf::Capacity) {
setNodeSize(this->map->height - 1, IP.second);
if (IP.first == IP.second - 1)
setNodeStop(this->map->height - 1, this->treeLeaf().stop(IP.first));
return;
}
// Leaf node has no space.
overflowLeaf();
IP = this->treeLeaf().insertFrom(this->treeLeafOffset(),
this->treeLeafSize(), a, b, y);
this->treeLeafOffset() = IP.first;
setNodeSize(this->map->height-1, IP.second);
if (IP.first == IP.second - 1)
setNodeStop(this->map->height - 1, this->treeLeaf().stop(IP.first));
// FIXME: Handle cross-node coalescing.
}
// overflowLeaf - Distribute entries of the current leaf node evenly among
// its siblings and ensure that the current node is not full.
// This may require allocating a new node.
template <typename KeyT, typename ValT, unsigned N, typename Traits>
void IntervalMap<KeyT, ValT, N, Traits>::
iterator::overflowLeaf() {
using namespace IntervalMapImpl;
unsigned CurSize[4];
Leaf *Node[4];
unsigned Nodes = 0;
unsigned Elements = 0;
unsigned Offset = this->treeLeafOffset();
// Do we have a left sibling?
NodeRef LeftSib = this->leftSibling(this->map->height-1);
if (LeftSib) {
Offset += Elements = CurSize[Nodes] = LeftSib.size();
Node[Nodes++] = &LeftSib.get<Leaf>();
}
// Current leaf node.
Elements += CurSize[Nodes] = this->treeLeafSize();
Node[Nodes++] = &this->treeLeaf();
// Do we have a right sibling?
NodeRef RightSib = this->rightSibling(this->map->height-1);
if (RightSib) {
Offset += Elements = CurSize[Nodes] = RightSib.size();
Node[Nodes++] = &RightSib.get<Leaf>();
}
// Do we need to allocate a new node?
unsigned NewNode = 0;
if (Elements + 1 > Nodes * Leaf::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->allocLeaf();
++Nodes;
}
// Compute the new element distribution.
unsigned NewSize[4];
IdxPair NewOffset = distribute(Nodes, Elements, Leaf::Capacity,
CurSize, NewSize, Offset, true);
// Move current location to the leftmost node.
if (LeftSib)
this->treeDecrement();
// 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;
}
}
// 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
// Elements have been rearranged, now update node sizes and stops.
unsigned Pos = 0;
for (;;) {
KeyT Stop = Node[Pos]->stop(NewSize[Pos]-1);
if (NewNode && Pos == NewNode)
insertNode(this->map->height - 1, NodeRef(Node[Pos], NewSize[Pos]), Stop);
else {
setNodeSize(this->map->height - 1, NewSize[Pos]);
setNodeStop(this->map->height - 1, Stop);
}
if (Pos + 1 == Nodes)
break;
this->treeIncrement();
++Pos;
}
// Where was I? Find NewOffset.
while(Pos != NewOffset.first) {
this->treeDecrement();
--Pos;
}
this->treeLeafOffset() = NewOffset.second;
}
} // namespace llvm
#endif