mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-30 21:29:28 +00:00
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173128 91177308-0d34-0410-b5e6-96231b3b80d8
527 lines
18 KiB
C++
527 lines
18 KiB
C++
//===--- llvm/ADT/SparseMultiSet.h - Sparse multiset ------------*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file defines the SparseMultiSet class, which adds multiset behavior to
|
|
// the SparseSet.
|
|
//
|
|
// A sparse multiset holds a small number of objects identified by integer keys
|
|
// from a moderately sized universe. The sparse multiset uses more memory than
|
|
// other containers in order to provide faster operations. Any key can map to
|
|
// multiple values. A SparseMultiSetNode class is provided, which serves as a
|
|
// convenient base class for the contents of a SparseMultiSet.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_ADT_SPARSEMULTISET_H
|
|
#define LLVM_ADT_SPARSEMULTISET_H
|
|
|
|
#include "llvm/ADT/SparseSet.h"
|
|
|
|
namespace llvm {
|
|
|
|
/// Fast multiset implementation for objects that can be identified by small
|
|
/// unsigned keys.
|
|
///
|
|
/// SparseMultiSet allocates memory proportional to the size of the key
|
|
/// universe, so it is not recommended for building composite data structures.
|
|
/// It is useful for algorithms that require a single set with fast operations.
|
|
///
|
|
/// Compared to DenseSet and DenseMap, SparseMultiSet provides constant-time
|
|
/// fast clear() as fast as a vector. The find(), insert(), and erase()
|
|
/// operations are all constant time, and typically faster than a hash table.
|
|
/// The iteration order doesn't depend on numerical key values, it only depends
|
|
/// on the order of insert() and erase() operations. Iteration order is the
|
|
/// insertion order. Iteration is only provided over elements of equivalent
|
|
/// keys, but iterators are bidirectional.
|
|
///
|
|
/// Compared to BitVector, SparseMultiSet<unsigned> uses 8x-40x more memory, but
|
|
/// offers constant-time clear() and size() operations as well as fast iteration
|
|
/// independent on the size of the universe.
|
|
///
|
|
/// SparseMultiSet contains a dense vector holding all the objects and a sparse
|
|
/// array holding indexes into the dense vector. Most of the memory is used by
|
|
/// the sparse array which is the size of the key universe. The SparseT template
|
|
/// parameter provides a space/speed tradeoff for sets holding many elements.
|
|
///
|
|
/// When SparseT is uint32_t, find() only touches up to 3 cache lines, but the
|
|
/// sparse array uses 4 x Universe bytes.
|
|
///
|
|
/// When SparseT is uint8_t (the default), find() touches up to 3+[N/256] cache
|
|
/// lines, but the sparse array is 4x smaller. N is the number of elements in
|
|
/// the set.
|
|
///
|
|
/// For sets that may grow to thousands of elements, SparseT should be set to
|
|
/// uint16_t or uint32_t.
|
|
///
|
|
/// Multiset behavior is provided by providing doubly linked lists for values
|
|
/// that are inlined in the dense vector. SparseMultiSet is a good choice when
|
|
/// one desires a growable number of entries per key, as it will retain the
|
|
/// SparseSet algorithmic properties despite being growable. Thus, it is often a
|
|
/// better choice than a SparseSet of growable containers or a vector of
|
|
/// vectors. SparseMultiSet also keeps iterators valid after erasure (provided
|
|
/// the iterators don't point to the element erased), allowing for more
|
|
/// intuitive and fast removal.
|
|
///
|
|
/// @tparam ValueT The type of objects in the set.
|
|
/// @tparam KeyFunctorT A functor that computes an unsigned index from KeyT.
|
|
/// @tparam SparseT An unsigned integer type. See above.
|
|
///
|
|
template<typename ValueT,
|
|
typename KeyFunctorT = llvm::identity<unsigned>,
|
|
typename SparseT = uint8_t>
|
|
class SparseMultiSet {
|
|
/// The actual data that's stored, as a doubly-linked list implemented via
|
|
/// indices into the DenseVector. The doubly linked list is implemented
|
|
/// circular in Prev indices, and INVALID-terminated in Next indices. This
|
|
/// provides efficient access to list tails. These nodes can also be
|
|
/// tombstones, in which case they are actually nodes in a single-linked
|
|
/// freelist of recyclable slots.
|
|
struct SMSNode {
|
|
static const unsigned INVALID = ~0U;
|
|
|
|
ValueT Data;
|
|
unsigned Prev;
|
|
unsigned Next;
|
|
|
|
SMSNode(ValueT D, unsigned P, unsigned N) : Data(D), Prev(P), Next(N) { }
|
|
|
|
/// List tails have invalid Nexts.
|
|
bool isTail() const {
|
|
return Next == INVALID;
|
|
}
|
|
|
|
/// Whether this node is a tombstone node, and thus is in our freelist.
|
|
bool isTombstone() const {
|
|
return Prev == INVALID;
|
|
}
|
|
|
|
/// Since the list is circular in Prev, all non-tombstone nodes have a valid
|
|
/// Prev.
|
|
bool isValid() const { return Prev != INVALID; }
|
|
};
|
|
|
|
typedef typename KeyFunctorT::argument_type KeyT;
|
|
typedef SmallVector<SMSNode, 8> DenseT;
|
|
DenseT Dense;
|
|
SparseT *Sparse;
|
|
unsigned Universe;
|
|
KeyFunctorT KeyIndexOf;
|
|
SparseSetValFunctor<KeyT, ValueT, KeyFunctorT> ValIndexOf;
|
|
|
|
/// We have a built-in recycler for reusing tombstone slots. This recycler
|
|
/// puts a singly-linked free list into tombstone slots, allowing us quick
|
|
/// erasure, iterator preservation, and dense size.
|
|
unsigned FreelistIdx;
|
|
unsigned NumFree;
|
|
|
|
unsigned sparseIndex(const ValueT &Val) const {
|
|
assert(ValIndexOf(Val) < Universe &&
|
|
"Invalid key in set. Did object mutate?");
|
|
return ValIndexOf(Val);
|
|
}
|
|
unsigned sparseIndex(const SMSNode &N) const { return sparseIndex(N.Data); }
|
|
|
|
// Disable copy construction and assignment.
|
|
// This data structure is not meant to be used that way.
|
|
SparseMultiSet(const SparseMultiSet&) LLVM_DELETED_FUNCTION;
|
|
SparseMultiSet &operator=(const SparseMultiSet&) LLVM_DELETED_FUNCTION;
|
|
|
|
/// Whether the given entry is the head of the list. List heads's previous
|
|
/// pointers are to the tail of the list, allowing for efficient access to the
|
|
/// list tail. D must be a valid entry node.
|
|
bool isHead(const SMSNode &D) const {
|
|
assert(D.isValid() && "Invalid node for head");
|
|
return Dense[D.Prev].isTail();
|
|
}
|
|
|
|
/// Whether the given entry is a singleton entry, i.e. the only entry with
|
|
/// that key.
|
|
bool isSingleton(const SMSNode &N) const {
|
|
assert(N.isValid() && "Invalid node for singleton");
|
|
// Is N its own predecessor?
|
|
return &Dense[N.Prev] == &N;
|
|
}
|
|
|
|
/// Add in the given SMSNode. Uses a free entry in our freelist if
|
|
/// available. Returns the index of the added node.
|
|
unsigned addValue(const ValueT& V, unsigned Prev, unsigned Next) {
|
|
if (NumFree == 0) {
|
|
Dense.push_back(SMSNode(V, Prev, Next));
|
|
return Dense.size() - 1;
|
|
}
|
|
|
|
// Peel off a free slot
|
|
unsigned Idx = FreelistIdx;
|
|
unsigned NextFree = Dense[Idx].Next;
|
|
assert(Dense[Idx].isTombstone() && "Non-tombstone free?");
|
|
|
|
Dense[Idx] = SMSNode(V, Prev, Next);
|
|
FreelistIdx = NextFree;
|
|
--NumFree;
|
|
return Idx;
|
|
}
|
|
|
|
/// Make the current index a new tombstone. Pushes it onto the freelist.
|
|
void makeTombstone(unsigned Idx) {
|
|
Dense[Idx].Prev = SMSNode::INVALID;
|
|
Dense[Idx].Next = FreelistIdx;
|
|
FreelistIdx = Idx;
|
|
++NumFree;
|
|
}
|
|
|
|
public:
|
|
typedef ValueT value_type;
|
|
typedef ValueT &reference;
|
|
typedef const ValueT &const_reference;
|
|
typedef ValueT *pointer;
|
|
typedef const ValueT *const_pointer;
|
|
|
|
SparseMultiSet()
|
|
: Sparse(0), Universe(0), FreelistIdx(SMSNode::INVALID), NumFree(0) { }
|
|
|
|
~SparseMultiSet() { free(Sparse); }
|
|
|
|
/// Set the universe size which determines the largest key the set can hold.
|
|
/// The universe must be sized before any elements can be added.
|
|
///
|
|
/// @param U Universe size. All object keys must be less than U.
|
|
///
|
|
void setUniverse(unsigned U) {
|
|
// It's not hard to resize the universe on a non-empty set, but it doesn't
|
|
// seem like a likely use case, so we can add that code when we need it.
|
|
assert(empty() && "Can only resize universe on an empty map");
|
|
// Hysteresis prevents needless reallocations.
|
|
if (U >= Universe/4 && U <= Universe)
|
|
return;
|
|
free(Sparse);
|
|
// The Sparse array doesn't actually need to be initialized, so malloc
|
|
// would be enough here, but that will cause tools like valgrind to
|
|
// complain about branching on uninitialized data.
|
|
Sparse = reinterpret_cast<SparseT*>(calloc(U, sizeof(SparseT)));
|
|
Universe = U;
|
|
}
|
|
|
|
/// Our iterators are iterators over the collection of objects that share a
|
|
/// key.
|
|
template<typename SMSPtrTy>
|
|
class iterator_base : public std::iterator<std::bidirectional_iterator_tag,
|
|
ValueT> {
|
|
friend class SparseMultiSet;
|
|
SMSPtrTy SMS;
|
|
unsigned Idx;
|
|
unsigned SparseIdx;
|
|
|
|
iterator_base(SMSPtrTy P, unsigned I, unsigned SI)
|
|
: SMS(P), Idx(I), SparseIdx(SI) { }
|
|
|
|
/// Whether our iterator has fallen outside our dense vector.
|
|
bool isEnd() const {
|
|
if (Idx == SMSNode::INVALID)
|
|
return true;
|
|
|
|
assert(Idx < SMS->Dense.size() && "Out of range, non-INVALID Idx?");
|
|
return false;
|
|
}
|
|
|
|
/// Whether our iterator is properly keyed, i.e. the SparseIdx is valid
|
|
bool isKeyed() const { return SparseIdx < SMS->Universe; }
|
|
|
|
unsigned Prev() const { return SMS->Dense[Idx].Prev; }
|
|
unsigned Next() const { return SMS->Dense[Idx].Next; }
|
|
|
|
void setPrev(unsigned P) { SMS->Dense[Idx].Prev = P; }
|
|
void setNext(unsigned N) { SMS->Dense[Idx].Next = N; }
|
|
|
|
public:
|
|
typedef std::iterator<std::bidirectional_iterator_tag, ValueT> super;
|
|
typedef typename super::value_type value_type;
|
|
typedef typename super::difference_type difference_type;
|
|
typedef typename super::pointer pointer;
|
|
typedef typename super::reference reference;
|
|
|
|
iterator_base(const iterator_base &RHS)
|
|
: SMS(RHS.SMS), Idx(RHS.Idx), SparseIdx(RHS.SparseIdx) { }
|
|
|
|
const iterator_base &operator=(const iterator_base &RHS) {
|
|
SMS = RHS.SMS;
|
|
Idx = RHS.Idx;
|
|
SparseIdx = RHS.SparseIdx;
|
|
return *this;
|
|
}
|
|
|
|
reference operator*() const {
|
|
assert(isKeyed() && SMS->sparseIndex(SMS->Dense[Idx].Data) == SparseIdx &&
|
|
"Dereferencing iterator of invalid key or index");
|
|
|
|
return SMS->Dense[Idx].Data;
|
|
}
|
|
pointer operator->() const { return &operator*(); }
|
|
|
|
/// Comparison operators
|
|
bool operator==(const iterator_base &RHS) const {
|
|
// end compares equal
|
|
if (SMS == RHS.SMS && Idx == RHS.Idx) {
|
|
assert((isEnd() || SparseIdx == RHS.SparseIdx) &&
|
|
"Same dense entry, but different keys?");
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool operator!=(const iterator_base &RHS) const {
|
|
return !operator==(RHS);
|
|
}
|
|
|
|
/// Increment and decrement operators
|
|
iterator_base &operator--() { // predecrement - Back up
|
|
assert(isKeyed() && "Decrementing an invalid iterator");
|
|
assert((isEnd() || !SMS->isHead(SMS->Dense[Idx])) &&
|
|
"Decrementing head of list");
|
|
|
|
// If we're at the end, then issue a new find()
|
|
if (isEnd())
|
|
Idx = SMS->findIndex(SparseIdx).Prev();
|
|
else
|
|
Idx = Prev();
|
|
|
|
return *this;
|
|
}
|
|
iterator_base &operator++() { // preincrement - Advance
|
|
assert(!isEnd() && isKeyed() && "Incrementing an invalid/end iterator");
|
|
Idx = Next();
|
|
return *this;
|
|
}
|
|
iterator_base operator--(int) { // postdecrement
|
|
iterator_base I(*this);
|
|
--*this;
|
|
return I;
|
|
}
|
|
iterator_base operator++(int) { // postincrement
|
|
iterator_base I(*this);
|
|
++*this;
|
|
return I;
|
|
}
|
|
};
|
|
typedef iterator_base<SparseMultiSet *> iterator;
|
|
typedef iterator_base<const SparseMultiSet *> const_iterator;
|
|
|
|
// Convenience types
|
|
typedef std::pair<iterator, iterator> RangePair;
|
|
|
|
/// Returns an iterator past this container. Note that such an iterator cannot
|
|
/// be decremented, but will compare equal to other end iterators.
|
|
iterator end() { return iterator(this, SMSNode::INVALID, SMSNode::INVALID); }
|
|
const_iterator end() const {
|
|
return const_iterator(this, SMSNode::INVALID, SMSNode::INVALID);
|
|
}
|
|
|
|
/// Returns true if the set is empty.
|
|
///
|
|
/// This is not the same as BitVector::empty().
|
|
///
|
|
bool empty() const { return size() == 0; }
|
|
|
|
/// Returns the number of elements in the set.
|
|
///
|
|
/// This is not the same as BitVector::size() which returns the size of the
|
|
/// universe.
|
|
///
|
|
unsigned size() const {
|
|
assert(NumFree <= Dense.size() && "Out-of-bounds free entries");
|
|
return Dense.size() - NumFree;
|
|
}
|
|
|
|
/// Clears the set. This is a very fast constant time operation.
|
|
///
|
|
void clear() {
|
|
// Sparse does not need to be cleared, see find().
|
|
Dense.clear();
|
|
NumFree = 0;
|
|
FreelistIdx = SMSNode::INVALID;
|
|
}
|
|
|
|
/// Find an element by its index.
|
|
///
|
|
/// @param Idx A valid index to find.
|
|
/// @returns An iterator to the element identified by key, or end().
|
|
///
|
|
iterator findIndex(unsigned Idx) {
|
|
assert(Idx < Universe && "Key out of range");
|
|
assert(std::numeric_limits<SparseT>::is_integer &&
|
|
!std::numeric_limits<SparseT>::is_signed &&
|
|
"SparseT must be an unsigned integer type");
|
|
const unsigned Stride = std::numeric_limits<SparseT>::max() + 1u;
|
|
for (unsigned i = Sparse[Idx], e = Dense.size(); i < e; i += Stride) {
|
|
const unsigned FoundIdx = sparseIndex(Dense[i]);
|
|
// Check that we're pointing at the correct entry and that it is the head
|
|
// of a valid list.
|
|
if (Idx == FoundIdx && Dense[i].isValid() && isHead(Dense[i]))
|
|
return iterator(this, i, Idx);
|
|
// Stride is 0 when SparseT >= unsigned. We don't need to loop.
|
|
if (!Stride)
|
|
break;
|
|
}
|
|
return end();
|
|
}
|
|
|
|
/// Find an element by its key.
|
|
///
|
|
/// @param Key A valid key to find.
|
|
/// @returns An iterator to the element identified by key, or end().
|
|
///
|
|
iterator find(const KeyT &Key) {
|
|
return findIndex(KeyIndexOf(Key));
|
|
}
|
|
|
|
const_iterator find(const KeyT &Key) const {
|
|
iterator I = const_cast<SparseMultiSet*>(this)->findIndex(KeyIndexOf(Key));
|
|
return const_iterator(I.SMS, I.Idx, KeyIndexOf(Key));
|
|
}
|
|
|
|
/// Returns the number of elements identified by Key. This will be linear in
|
|
/// the number of elements of that key.
|
|
unsigned count(const KeyT &Key) const {
|
|
unsigned Ret = 0;
|
|
for (const_iterator It = find(Key); It != end(); ++It)
|
|
++Ret;
|
|
|
|
return Ret;
|
|
}
|
|
|
|
/// Returns true if this set contains an element identified by Key.
|
|
bool contains(const KeyT &Key) const {
|
|
return find(Key) != end();
|
|
}
|
|
|
|
/// Return the head and tail of the subset's list, otherwise returns end().
|
|
iterator getHead(const KeyT &Key) { return find(Key); }
|
|
iterator getTail(const KeyT &Key) {
|
|
iterator I = find(Key);
|
|
if (I != end())
|
|
I = iterator(this, I.Prev(), KeyIndexOf(Key));
|
|
return I;
|
|
}
|
|
|
|
/// The bounds of the range of items sharing Key K. First member is the head
|
|
/// of the list, and the second member is a decrementable end iterator for
|
|
/// that key.
|
|
RangePair equal_range(const KeyT &K) {
|
|
iterator B = find(K);
|
|
iterator E = iterator(this, SMSNode::INVALID, B.SparseIdx);
|
|
return make_pair(B, E);
|
|
}
|
|
|
|
/// Insert a new element at the tail of the subset list. Returns an iterator
|
|
/// to the newly added entry.
|
|
iterator insert(const ValueT &Val) {
|
|
unsigned Idx = sparseIndex(Val);
|
|
iterator I = findIndex(Idx);
|
|
|
|
unsigned NodeIdx = addValue(Val, SMSNode::INVALID, SMSNode::INVALID);
|
|
|
|
if (I == end()) {
|
|
// Make a singleton list
|
|
Sparse[Idx] = NodeIdx;
|
|
Dense[NodeIdx].Prev = NodeIdx;
|
|
return iterator(this, NodeIdx, Idx);
|
|
}
|
|
|
|
// Stick it at the end.
|
|
unsigned HeadIdx = I.Idx;
|
|
unsigned TailIdx = I.Prev();
|
|
Dense[TailIdx].Next = NodeIdx;
|
|
Dense[HeadIdx].Prev = NodeIdx;
|
|
Dense[NodeIdx].Prev = TailIdx;
|
|
|
|
return iterator(this, NodeIdx, Idx);
|
|
}
|
|
|
|
/// Erases an existing element identified by a valid iterator.
|
|
///
|
|
/// This invalidates iterators pointing at the same entry, but erase() returns
|
|
/// an iterator pointing to the next element in the subset's list. This makes
|
|
/// it possible to erase selected elements while iterating over the subset:
|
|
///
|
|
/// tie(I, E) = Set.equal_range(Key);
|
|
/// while (I != E)
|
|
/// if (test(*I))
|
|
/// I = Set.erase(I);
|
|
/// else
|
|
/// ++I;
|
|
///
|
|
/// Note that if the last element in the subset list is erased, this will
|
|
/// return an end iterator which can be decremented to get the new tail (if it
|
|
/// exists):
|
|
///
|
|
/// tie(B, I) = Set.equal_range(Key);
|
|
/// for (bool isBegin = B == I; !isBegin; /* empty */) {
|
|
/// isBegin = (--I) == B;
|
|
/// if (test(I))
|
|
/// break;
|
|
/// I = erase(I);
|
|
/// }
|
|
iterator erase(iterator I) {
|
|
assert(I.isKeyed() && !I.isEnd() && !Dense[I.Idx].isTombstone() &&
|
|
"erasing invalid/end/tombstone iterator");
|
|
|
|
// First, unlink the node from its list. Then swap the node out with the
|
|
// dense vector's last entry
|
|
iterator NextI = unlink(Dense[I.Idx]);
|
|
|
|
// Put in a tombstone.
|
|
makeTombstone(I.Idx);
|
|
|
|
return NextI;
|
|
}
|
|
|
|
/// Erase all elements with the given key. This invalidates all
|
|
/// iterators of that key.
|
|
void eraseAll(const KeyT &K) {
|
|
for (iterator I = find(K); I != end(); /* empty */)
|
|
I = erase(I);
|
|
}
|
|
|
|
private:
|
|
/// Unlink the node from its list. Returns the next node in the list.
|
|
iterator unlink(const SMSNode &N) {
|
|
if (isSingleton(N)) {
|
|
// Singleton is already unlinked
|
|
assert(N.Next == SMSNode::INVALID && "Singleton has next?");
|
|
return iterator(this, SMSNode::INVALID, ValIndexOf(N.Data));
|
|
}
|
|
|
|
if (isHead(N)) {
|
|
// If we're the head, then update the sparse array and our next.
|
|
Sparse[sparseIndex(N)] = N.Next;
|
|
Dense[N.Next].Prev = N.Prev;
|
|
return iterator(this, N.Next, ValIndexOf(N.Data));
|
|
}
|
|
|
|
if (N.isTail()) {
|
|
// If we're the tail, then update our head and our previous.
|
|
findIndex(sparseIndex(N)).setPrev(N.Prev);
|
|
Dense[N.Prev].Next = N.Next;
|
|
|
|
// Give back an end iterator that can be decremented
|
|
iterator I(this, N.Prev, ValIndexOf(N.Data));
|
|
return ++I;
|
|
}
|
|
|
|
// Otherwise, just drop us
|
|
Dense[N.Next].Prev = N.Prev;
|
|
Dense[N.Prev].Next = N.Next;
|
|
return iterator(this, N.Next, ValIndexOf(N.Data));
|
|
}
|
|
};
|
|
|
|
} // end namespace llvm
|
|
|
|
#endif
|