IntervalMap.h revision ddd0e65dba1de71eaa8901cd6f787754e34c3fe0
1//===- llvm/ADT/IntervalMap.h - A sorted interval map -----------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements a coalescing interval map for small objects. 11// 12// KeyT objects are mapped to ValT objects. Intervals of keys that map to the 13// same value are represented in a compressed form. 14// 15// Iterators provide ordered access to the compressed intervals rather than the 16// individual keys, and insert and erase operations use key intervals as well. 17// 18// Like SmallVector, IntervalMap will store the first N intervals in the map 19// object itself without any allocations. When space is exhausted it switches to 20// a B+-tree representation with very small overhead for small key and value 21// objects. 22// 23// A Traits class specifies how keys are compared. It also allows IntervalMap to 24// work with both closed and half-open intervals. 25// 26// Keys and values are not stored next to each other in a std::pair, so we don't 27// provide such a value_type. Dereferencing iterators only returns the mapped 28// value. The interval bounds are accessible through the start() and stop() 29// iterator methods. 30// 31// IntervalMap is optimized for small key and value objects, 4 or 8 bytes each 32// is the optimal size. For large objects use std::map instead. 33// 34//===----------------------------------------------------------------------===// 35// 36// Synopsis: 37// 38// template <typename KeyT, typename ValT, unsigned N, typename Traits> 39// class IntervalMap { 40// public: 41// typedef KeyT key_type; 42// typedef ValT mapped_type; 43// typedef RecyclingAllocator<...> Allocator; 44// class iterator; 45// class const_iterator; 46// 47// explicit IntervalMap(Allocator&); 48// ~IntervalMap(): 49// 50// bool empty() const; 51// KeyT start() const; 52// KeyT stop() const; 53// ValT lookup(KeyT x, Value NotFound = Value()) const; 54// 55// const_iterator begin() const; 56// const_iterator end() const; 57// iterator begin(); 58// iterator end(); 59// const_iterator find(KeyT x) const; 60// iterator find(KeyT x); 61// 62// void insert(KeyT a, KeyT b, ValT y); 63// void clear(); 64// }; 65// 66// template <typename KeyT, typename ValT, unsigned N, typename Traits> 67// class IntervalMap::const_iterator : 68// public std::iterator<std::bidirectional_iterator_tag, ValT> { 69// public: 70// bool operator==(const const_iterator &) const; 71// bool operator!=(const const_iterator &) const; 72// bool valid() const; 73// 74// const KeyT &start() const; 75// const KeyT &stop() const; 76// const ValT &value() const; 77// const ValT &operator*() const; 78// const ValT *operator->() const; 79// 80// const_iterator &operator++(); 81// const_iterator &operator++(int); 82// const_iterator &operator--(); 83// const_iterator &operator--(int); 84// void goToBegin(); 85// void goToEnd(); 86// void find(KeyT x); 87// void advanceTo(KeyT x); 88// }; 89// 90// template <typename KeyT, typename ValT, unsigned N, typename Traits> 91// class IntervalMap::iterator : public const_iterator { 92// public: 93// void insert(KeyT a, KeyT b, Value y); 94// void erase(); 95// }; 96// 97//===----------------------------------------------------------------------===// 98 99#ifndef LLVM_ADT_INTERVALMAP_H 100#define LLVM_ADT_INTERVALMAP_H 101 102#include "llvm/ADT/SmallVector.h" 103#include "llvm/ADT/PointerIntPair.h" 104#include "llvm/Support/Allocator.h" 105#include "llvm/Support/RecyclingAllocator.h" 106#include <limits> 107#include <iterator> 108 109// FIXME: Remove debugging code. 110#include "llvm/Support/raw_ostream.h" 111 112namespace llvm { 113 114 115//===----------------------------------------------------------------------===// 116//--- Key traits ---// 117//===----------------------------------------------------------------------===// 118// 119// The IntervalMap works with closed or half-open intervals. 120// Adjacent intervals that map to the same value are coalesced. 121// 122// The IntervalMapInfo traits class is used to determine if a key is contained 123// in an interval, and if two intervals are adjacent so they can be coalesced. 124// The provided implementation works for closed integer intervals, other keys 125// probably need a specialized version. 126// 127// The point x is contained in [a;b] when !startLess(x, a) && !stopLess(b, x). 128// 129// It is assumed that (a;b] half-open intervals are not used, only [a;b) is 130// allowed. This is so that stopLess(a, b) can be used to determine if two 131// intervals overlap. 132// 133//===----------------------------------------------------------------------===// 134 135template <typename T> 136struct IntervalMapInfo { 137 138 /// startLess - Return true if x is not in [a;b]. 139 /// This is x < a both for closed intervals and for [a;b) half-open intervals. 140 static inline bool startLess(const T &x, const T &a) { 141 return x < a; 142 } 143 144 /// stopLess - Return true if x is not in [a;b]. 145 /// This is b < x for a closed interval, b <= x for [a;b) half-open intervals. 146 static inline bool stopLess(const T &b, const T &x) { 147 return b < x; 148 } 149 150 /// adjacent - Return true when the intervals [x;a] and [b;y] can coalesce. 151 /// This is a+1 == b for closed intervals, a == b for half-open intervals. 152 static inline bool adjacent(const T &a, const T &b) { 153 return a+1 == b; 154 } 155 156}; 157 158/// IntervalMapImpl - Namespace used for IntervalMap implementation details. 159/// It should be considered private to the implementation. 160namespace IntervalMapImpl { 161 162// Forward declarations. 163template <typename, typename, unsigned, typename> class LeafNode; 164template <typename, typename, unsigned, typename> class BranchNode; 165 166typedef std::pair<unsigned,unsigned> IdxPair; 167 168 169//===----------------------------------------------------------------------===// 170//--- Node Storage ---// 171//===----------------------------------------------------------------------===// 172// 173// Both leaf and branch nodes store vectors of pairs. 174// Leaves store ((KeyT, KeyT), ValT) pairs, branches use (NodeRef, KeyT). 175// 176// Keys and values are stored in separate arrays to avoid padding caused by 177// different object alignments. This also helps improve locality of reference 178// when searching the keys. 179// 180// The nodes don't know how many elements they contain - that information is 181// stored elsewhere. Omitting the size field prevents padding and allows a node 182// to fill the allocated cache lines completely. 183// 184// These are typical key and value sizes, the node branching factor (N), and 185// wasted space when nodes are sized to fit in three cache lines (192 bytes): 186// 187// T1 T2 N Waste Used by 188// 4 4 24 0 Branch<4> (32-bit pointers) 189// 8 4 16 0 Leaf<4,4>, Branch<4> 190// 8 8 12 0 Leaf<4,8>, Branch<8> 191// 16 4 9 12 Leaf<8,4> 192// 16 8 8 0 Leaf<8,8> 193// 194//===----------------------------------------------------------------------===// 195 196template <typename T1, typename T2, unsigned N> 197class NodeBase { 198public: 199 enum { Capacity = N }; 200 201 T1 first[N]; 202 T2 second[N]; 203 204 /// copy - Copy elements from another node. 205 /// @param Other Node elements are copied from. 206 /// @param i Beginning of the source range in other. 207 /// @param j Beginning of the destination range in this. 208 /// @param Count Number of elements to copy. 209 template <unsigned M> 210 void copy(const NodeBase<T1, T2, M> &Other, unsigned i, 211 unsigned j, unsigned Count) { 212 assert(i + Count <= M && "Invalid source range"); 213 assert(j + Count <= N && "Invalid dest range"); 214 std::copy(Other.first + i, Other.first + i + Count, first + j); 215 std::copy(Other.second + i, Other.second + i + Count, second + j); 216 } 217 218 /// moveLeft - Move elements to the left. 219 /// @param i Beginning of the source range. 220 /// @param j Beginning of the destination range. 221 /// @param Count Number of elements to copy. 222 void moveLeft(unsigned i, unsigned j, unsigned Count) { 223 assert(j <= i && "Use moveRight shift elements right"); 224 copy(*this, i, j, Count); 225 } 226 227 /// moveRight - Move elements to the right. 228 /// @param i Beginning of the source range. 229 /// @param j Beginning of the destination range. 230 /// @param Count Number of elements to copy. 231 void moveRight(unsigned i, unsigned j, unsigned Count) { 232 assert(i <= j && "Use moveLeft shift elements left"); 233 assert(j + Count <= N && "Invalid range"); 234 std::copy_backward(first + i, first + i + Count, first + j + Count); 235 std::copy_backward(second + i, second + i + Count, second + j + Count); 236 } 237 238 /// erase - Erase elements [i;j). 239 /// @param i Beginning of the range to erase. 240 /// @param j End of the range. (Exclusive). 241 /// @param Size Number of elements in node. 242 void erase(unsigned i, unsigned j, unsigned Size) { 243 moveLeft(j, i, Size - j); 244 } 245 246 /// shift - Shift elements [i;size) 1 position to the right. 247 /// @param i Beginning of the range to move. 248 /// @param Size Number of elements in node. 249 void shift(unsigned i, unsigned Size) { 250 moveRight(i, i + 1, Size - i); 251 } 252 253 /// transferToLeftSib - Transfer elements to a left sibling node. 254 /// @param Size Number of elements in this. 255 /// @param Sib Left sibling node. 256 /// @param SSize Number of elements in sib. 257 /// @param Count Number of elements to transfer. 258 void transferToLeftSib(unsigned Size, NodeBase &Sib, unsigned SSize, 259 unsigned Count) { 260 Sib.copy(*this, 0, SSize, Count); 261 erase(0, Count, Size); 262 } 263 264 /// transferToRightSib - Transfer elements to a right sibling node. 265 /// @param Size Number of elements in this. 266 /// @param Sib Right sibling node. 267 /// @param SSize Number of elements in sib. 268 /// @param Count Number of elements to transfer. 269 void transferToRightSib(unsigned Size, NodeBase &Sib, unsigned SSize, 270 unsigned Count) { 271 Sib.moveRight(0, Count, SSize); 272 Sib.copy(*this, Size-Count, 0, Count); 273 } 274 275 /// adjustFromLeftSib - Adjust the number if elements in this node by moving 276 /// elements to or from a left sibling node. 277 /// @param Size Number of elements in this. 278 /// @param Sib Right sibling node. 279 /// @param SSize Number of elements in sib. 280 /// @param Add The number of elements to add to this node, possibly < 0. 281 /// @return Number of elements added to this node, possibly negative. 282 int adjustFromLeftSib(unsigned Size, NodeBase &Sib, unsigned SSize, int Add) { 283 if (Add > 0) { 284 // We want to grow, copy from sib. 285 unsigned Count = std::min(std::min(unsigned(Add), SSize), N - Size); 286 Sib.transferToRightSib(SSize, *this, Size, Count); 287 return Count; 288 } else { 289 // We want to shrink, copy to sib. 290 unsigned Count = std::min(std::min(unsigned(-Add), Size), N - SSize); 291 transferToLeftSib(Size, Sib, SSize, Count); 292 return -Count; 293 } 294 } 295}; 296 297 298//===----------------------------------------------------------------------===// 299//--- NodeSizer ---// 300//===----------------------------------------------------------------------===// 301// 302// Compute node sizes from key and value types. 303// 304// The branching factors are chosen to make nodes fit in three cache lines. 305// This may not be possible if keys or values are very large. Such large objects 306// are handled correctly, but a std::map would probably give better performance. 307// 308//===----------------------------------------------------------------------===// 309 310enum { 311 // Cache line size. Most architectures have 32 or 64 byte cache lines. 312 // We use 64 bytes here because it provides good branching factors. 313 Log2CacheLine = 6, 314 CacheLineBytes = 1 << Log2CacheLine, 315 DesiredNodeBytes = 3 * CacheLineBytes 316}; 317 318template <typename KeyT, typename ValT> 319struct NodeSizer { 320 enum { 321 // Compute the leaf node branching factor that makes a node fit in three 322 // cache lines. The branching factor must be at least 3, or some B+-tree 323 // balancing algorithms won't work. 324 // LeafSize can't be larger than CacheLineBytes. This is required by the 325 // PointerIntPair used by NodeRef. 326 DesiredLeafSize = DesiredNodeBytes / 327 static_cast<unsigned>(2*sizeof(KeyT)+sizeof(ValT)), 328 MinLeafSize = 3, 329 LeafSize = DesiredLeafSize > MinLeafSize ? DesiredLeafSize : MinLeafSize 330 }; 331 332 typedef NodeBase<std::pair<KeyT, KeyT>, ValT, LeafSize> LeafBase; 333 334 enum { 335 // Now that we have the leaf branching factor, compute the actual allocation 336 // unit size by rounding up to a whole number of cache lines. 337 AllocBytes = (sizeof(LeafBase) + CacheLineBytes-1) & ~(CacheLineBytes-1), 338 339 // Determine the branching factor for branch nodes. 340 BranchSize = AllocBytes / 341 static_cast<unsigned>(sizeof(KeyT) + sizeof(void*)) 342 }; 343 344 /// Allocator - The recycling allocator used for both branch and leaf nodes. 345 /// This typedef is very likely to be identical for all IntervalMaps with 346 /// reasonably sized entries, so the same allocator can be shared among 347 /// different kinds of maps. 348 typedef RecyclingAllocator<BumpPtrAllocator, char, 349 AllocBytes, CacheLineBytes> Allocator; 350 351}; 352 353 354//===----------------------------------------------------------------------===// 355//--- NodeRef ---// 356//===----------------------------------------------------------------------===// 357// 358// B+-tree nodes can be leaves or branches, so we need a polymorphic node 359// pointer that can point to both kinds. 360// 361// All nodes are cache line aligned and the low 6 bits of a node pointer are 362// always 0. These bits are used to store the number of elements in the 363// referenced node. Besides saving space, placing node sizes in the parents 364// allow tree balancing algorithms to run without faulting cache lines for nodes 365// that may not need to be modified. 366// 367// A NodeRef doesn't know whether it references a leaf node or a branch node. 368// It is the responsibility of the caller to use the correct types. 369// 370// Nodes are never supposed to be empty, and it is invalid to store a node size 371// of 0 in a NodeRef. The valid range of sizes is 1-64. 372// 373//===----------------------------------------------------------------------===// 374 375struct CacheAlignedPointerTraits { 376 static inline void *getAsVoidPointer(void *P) { return P; } 377 static inline void *getFromVoidPointer(void *P) { return P; } 378 enum { NumLowBitsAvailable = Log2CacheLine }; 379}; 380 381class NodeRef { 382 PointerIntPair<void*, Log2CacheLine, unsigned, CacheAlignedPointerTraits> pip; 383 384public: 385 /// NodeRef - Create a null ref. 386 NodeRef() {} 387 388 /// operator bool - Detect a null ref. 389 operator bool() const { return pip.getOpaqueValue(); } 390 391 /// NodeRef - Create a reference to the node p with n elements. 392 template <typename NodeT> 393 NodeRef(NodeT *p, unsigned n) : pip(p, n - 1) { 394 assert(n <= NodeT::Capacity && "Size too big for node"); 395 } 396 397 /// size - Return the number of elements in the referenced node. 398 unsigned size() const { return pip.getInt() + 1; } 399 400 /// setSize - Update the node size. 401 void setSize(unsigned n) { pip.setInt(n - 1); } 402 403 /// subtree - Access the i'th subtree reference in a branch node. 404 /// This depends on branch nodes storing the NodeRef array as their first 405 /// member. 406 NodeRef &subtree(unsigned i) { 407 return reinterpret_cast<NodeRef*>(pip.getPointer())[i]; 408 } 409 410 /// get - Dereference as a NodeT reference. 411 template <typename NodeT> 412 NodeT &get() const { 413 return *reinterpret_cast<NodeT*>(pip.getPointer()); 414 } 415 416 bool operator==(const NodeRef &RHS) const { 417 if (pip == RHS.pip) 418 return true; 419 assert(pip.getPointer() != RHS.pip.getPointer() && "Inconsistent NodeRefs"); 420 return false; 421 } 422 423 bool operator!=(const NodeRef &RHS) const { 424 return !operator==(RHS); 425 } 426}; 427 428//===----------------------------------------------------------------------===// 429//--- Leaf nodes ---// 430//===----------------------------------------------------------------------===// 431// 432// Leaf nodes store up to N disjoint intervals with corresponding values. 433// 434// The intervals are kept sorted and fully coalesced so there are no adjacent 435// intervals mapping to the same value. 436// 437// These constraints are always satisfied: 438// 439// - Traits::stopLess(start(i), stop(i)) - Non-empty, sane intervals. 440// 441// - Traits::stopLess(stop(i), start(i + 1) - Sorted. 442// 443// - value(i) != value(i + 1) || !Traits::adjacent(stop(i), start(i + 1)) 444// - Fully coalesced. 445// 446//===----------------------------------------------------------------------===// 447 448template <typename KeyT, typename ValT, unsigned N, typename Traits> 449class LeafNode : public NodeBase<std::pair<KeyT, KeyT>, ValT, N> { 450public: 451 const KeyT &start(unsigned i) const { return this->first[i].first; } 452 const KeyT &stop(unsigned i) const { return this->first[i].second; } 453 const ValT &value(unsigned i) const { return this->second[i]; } 454 455 KeyT &start(unsigned i) { return this->first[i].first; } 456 KeyT &stop(unsigned i) { return this->first[i].second; } 457 ValT &value(unsigned i) { return this->second[i]; } 458 459 /// findFrom - Find the first interval after i that may contain x. 460 /// @param i Starting index for the search. 461 /// @param Size Number of elements in node. 462 /// @param x Key to search for. 463 /// @return First index with !stopLess(key[i].stop, x), or size. 464 /// This is the first interval that can possibly contain x. 465 unsigned findFrom(unsigned i, unsigned Size, KeyT x) const { 466 assert(i <= Size && Size <= N && "Bad indices"); 467 assert((i == 0 || Traits::stopLess(stop(i - 1), x)) && 468 "Index is past the needed point"); 469 while (i != Size && Traits::stopLess(stop(i), x)) ++i; 470 return i; 471 } 472 473 /// safeFind - Find an interval that is known to exist. This is the same as 474 /// findFrom except is it assumed that x is at least within range of the last 475 /// interval. 476 /// @param i Starting index for the search. 477 /// @param x Key to search for. 478 /// @return First index with !stopLess(key[i].stop, x), never size. 479 /// This is the first interval that can possibly contain x. 480 unsigned safeFind(unsigned i, KeyT x) const { 481 assert(i < N && "Bad index"); 482 assert((i == 0 || Traits::stopLess(stop(i - 1), x)) && 483 "Index is past the needed point"); 484 while (Traits::stopLess(stop(i), x)) ++i; 485 assert(i < N && "Unsafe intervals"); 486 return i; 487 } 488 489 /// safeLookup - Lookup mapped value for a safe key. 490 /// It is assumed that x is within range of the last entry. 491 /// @param x Key to search for. 492 /// @param NotFound Value to return if x is not in any interval. 493 /// @return The mapped value at x or NotFound. 494 ValT safeLookup(KeyT x, ValT NotFound) const { 495 unsigned i = safeFind(0, x); 496 return Traits::startLess(x, start(i)) ? NotFound : value(i); 497 } 498 499 IdxPair insertFrom(unsigned i, unsigned Size, KeyT a, KeyT b, ValT y); 500 unsigned extendStop(unsigned i, unsigned Size, KeyT b); 501 502#ifndef NDEBUG 503 void dump(unsigned Size) { 504 errs() << " N" << this << " [shape=record label=\"{ " << Size << '/' << N; 505 for (unsigned i = 0; i != Size; ++i) 506 errs() << " | {" << start(i) << '-' << stop(i) << "|" << value(i) << '}'; 507 errs() << "}\"];\n"; 508 } 509#endif 510 511}; 512 513/// insertFrom - Add mapping of [a;b] to y if possible, coalescing as much as 514/// possible. This may cause the node to grow by 1, or it may cause the node 515/// to shrink because of coalescing. 516/// @param i Starting index = insertFrom(0, size, a) 517/// @param Size Number of elements in node. 518/// @param a Interval start. 519/// @param b Interval stop. 520/// @param y Value be mapped. 521/// @return (insert position, new size), or (i, Capacity+1) on overflow. 522template <typename KeyT, typename ValT, unsigned N, typename Traits> 523IdxPair LeafNode<KeyT, ValT, N, Traits>:: 524insertFrom(unsigned i, unsigned Size, KeyT a, KeyT b, ValT y) { 525 assert(i <= Size && Size <= N && "Invalid index"); 526 assert(!Traits::stopLess(b, a) && "Invalid interval"); 527 528 // Verify the findFrom invariant. 529 assert((i == 0 || Traits::stopLess(stop(i - 1), a))); 530 assert((i == Size || !Traits::stopLess(stop(i), a))); 531 532 // Coalesce with previous interval. 533 if (i && value(i - 1) == y && Traits::adjacent(stop(i - 1), a)) 534 return IdxPair(i - 1, extendStop(i - 1, Size, b)); 535 536 // Detect overflow. 537 if (i == N) 538 return IdxPair(i, N + 1); 539 540 // Add new interval at end. 541 if (i == Size) { 542 start(i) = a; 543 stop(i) = b; 544 value(i) = y; 545 return IdxPair(i, Size + 1); 546 } 547 548 // Overlapping intervals? 549 if (!Traits::stopLess(b, start(i))) { 550 assert(value(i) == y && "Inconsistent values in overlapping intervals"); 551 if (Traits::startLess(a, start(i))) 552 start(i) = a; 553 return IdxPair(i, extendStop(i, Size, b)); 554 } 555 556 // Try to coalesce with following interval. 557 if (value(i) == y && Traits::adjacent(b, start(i))) { 558 start(i) = a; 559 return IdxPair(i, Size); 560 } 561 562 // We must insert before i. Detect overflow. 563 if (Size == N) 564 return IdxPair(i, N + 1); 565 566 // Insert before i. 567 this->shift(i, Size); 568 start(i) = a; 569 stop(i) = b; 570 value(i) = y; 571 return IdxPair(i, Size + 1); 572} 573 574/// extendStop - Extend stop(i) to b, coalescing with following intervals. 575/// @param i Interval to extend. 576/// @param Size Number of elements in node. 577/// @param b New interval end point. 578/// @return New node size after coalescing. 579template <typename KeyT, typename ValT, unsigned N, typename Traits> 580unsigned LeafNode<KeyT, ValT, N, Traits>:: 581extendStop(unsigned i, unsigned Size, KeyT b) { 582 assert(i < Size && Size <= N && "Bad indices"); 583 584 // Are we even extending the interval? 585 if (Traits::startLess(b, stop(i))) 586 return Size; 587 588 // Find the first interval that may be preserved. 589 unsigned j = findFrom(i + 1, Size, b); 590 if (j < Size) { 591 // Would key[i] overlap key[j] after the extension? 592 if (Traits::stopLess(b, start(j))) { 593 // Not overlapping. Perhaps adjacent and coalescable? 594 if (value(i) == value(j) && Traits::adjacent(b, start(j))) 595 b = stop(j++); 596 } else { 597 // Overlap. Include key[j] in the new interval. 598 assert(value(i) == value(j) && "Overlapping values"); 599 b = stop(j++); 600 } 601 } 602 stop(i) = b; 603 604 // Entries [i+1;j) were coalesced. 605 if (i + 1 < j && j < Size) 606 this->erase(i + 1, j, Size); 607 return Size - (j - (i + 1)); 608} 609 610 611//===----------------------------------------------------------------------===// 612//--- Branch nodes ---// 613//===----------------------------------------------------------------------===// 614// 615// A branch node stores references to 1--N subtrees all of the same height. 616// 617// The key array in a branch node holds the rightmost stop key of each subtree. 618// It is redundant to store the last stop key since it can be found in the 619// parent node, but doing so makes tree balancing a lot simpler. 620// 621// It is unusual for a branch node to only have one subtree, but it can happen 622// in the root node if it is smaller than the normal nodes. 623// 624// When all of the leaf nodes from all the subtrees are concatenated, they must 625// satisfy the same constraints as a single leaf node. They must be sorted, 626// sane, and fully coalesced. 627// 628//===----------------------------------------------------------------------===// 629 630template <typename KeyT, typename ValT, unsigned N, typename Traits> 631class BranchNode : public NodeBase<NodeRef, KeyT, N> { 632public: 633 const KeyT &stop(unsigned i) const { return this->second[i]; } 634 const NodeRef &subtree(unsigned i) const { return this->first[i]; } 635 636 KeyT &stop(unsigned i) { return this->second[i]; } 637 NodeRef &subtree(unsigned i) { return this->first[i]; } 638 639 /// findFrom - Find the first subtree after i that may contain x. 640 /// @param i Starting index for the search. 641 /// @param Size Number of elements in node. 642 /// @param x Key to search for. 643 /// @return First index with !stopLess(key[i], x), or size. 644 /// This is the first subtree that can possibly contain x. 645 unsigned findFrom(unsigned i, unsigned Size, KeyT x) const { 646 assert(i <= Size && Size <= N && "Bad indices"); 647 assert((i == 0 || Traits::stopLess(stop(i - 1), x)) && 648 "Index to findFrom is past the needed point"); 649 while (i != Size && Traits::stopLess(stop(i), x)) ++i; 650 return i; 651 } 652 653 /// safeFind - Find a subtree that is known to exist. This is the same as 654 /// findFrom except is it assumed that x is in range. 655 /// @param i Starting index for the search. 656 /// @param x Key to search for. 657 /// @return First index with !stopLess(key[i], x), never size. 658 /// This is the first subtree that can possibly contain x. 659 unsigned safeFind(unsigned i, KeyT x) const { 660 assert(i < N && "Bad index"); 661 assert((i == 0 || Traits::stopLess(stop(i - 1), x)) && 662 "Index is past the needed point"); 663 while (Traits::stopLess(stop(i), x)) ++i; 664 assert(i < N && "Unsafe intervals"); 665 return i; 666 } 667 668 /// safeLookup - Get the subtree containing x, Assuming that x is in range. 669 /// @param x Key to search for. 670 /// @return Subtree containing x 671 NodeRef safeLookup(KeyT x) const { 672 return subtree(safeFind(0, x)); 673 } 674 675 /// insert - Insert a new (subtree, stop) pair. 676 /// @param i Insert position, following entries will be shifted. 677 /// @param Size Number of elements in node. 678 /// @param Node Subtree to insert. 679 /// @param Stop Last key in subtree. 680 void insert(unsigned i, unsigned Size, NodeRef Node, KeyT Stop) { 681 assert(Size < N && "branch node overflow"); 682 assert(i <= Size && "Bad insert position"); 683 this->shift(i, Size); 684 subtree(i) = Node; 685 stop(i) = Stop; 686 } 687 688#ifndef NDEBUG 689 void dump(unsigned Size) { 690 errs() << " N" << this << " [shape=record label=\"" << Size << '/' << N; 691 for (unsigned i = 0; i != Size; ++i) 692 errs() << " | <s" << i << "> " << stop(i); 693 errs() << "\"];\n"; 694 for (unsigned i = 0; i != Size; ++i) 695 errs() << " N" << this << ":s" << i << " -> N" 696 << &subtree(i).template get<BranchNode>() << ";\n"; 697 } 698#endif 699 700}; 701 702} // namespace IntervalMapImpl 703 704 705//===----------------------------------------------------------------------===// 706//--- IntervalMap ----// 707//===----------------------------------------------------------------------===// 708 709template <typename KeyT, typename ValT, 710 unsigned N = IntervalMapImpl::NodeSizer<KeyT, ValT>::LeafSize, 711 typename Traits = IntervalMapInfo<KeyT> > 712class IntervalMap { 713 typedef IntervalMapImpl::NodeSizer<KeyT, ValT> Sizer; 714 typedef IntervalMapImpl::LeafNode<KeyT, ValT, Sizer::LeafSize, Traits> Leaf; 715 typedef IntervalMapImpl::BranchNode<KeyT, ValT, Sizer::BranchSize, Traits> 716 Branch; 717 typedef IntervalMapImpl::LeafNode<KeyT, ValT, N, Traits> RootLeaf; 718 typedef IntervalMapImpl::IdxPair IdxPair; 719 720 // The RootLeaf capacity is given as a template parameter. We must compute the 721 // corresponding RootBranch capacity. 722 enum { 723 DesiredRootBranchCap = (sizeof(RootLeaf) - sizeof(KeyT)) / 724 (sizeof(KeyT) + sizeof(IntervalMapImpl::NodeRef)), 725 RootBranchCap = DesiredRootBranchCap ? DesiredRootBranchCap : 1 726 }; 727 728 typedef IntervalMapImpl::BranchNode<KeyT, ValT, RootBranchCap, Traits> 729 RootBranch; 730 731 // When branched, we store a global start key as well as the branch node. 732 struct RootBranchData { 733 KeyT start; 734 RootBranch node; 735 }; 736 737 enum { 738 RootDataSize = sizeof(RootBranchData) > sizeof(RootLeaf) ? 739 sizeof(RootBranchData) : sizeof(RootLeaf) 740 }; 741 742public: 743 typedef typename Sizer::Allocator Allocator; 744 745private: 746 // The root data is either a RootLeaf or a RootBranchData instance. 747 // We can't put them in a union since C++03 doesn't allow non-trivial 748 // constructors in unions. 749 // Instead, we use a char array with pointer alignment. The alignment is 750 // ensured by the allocator member in the class, but still verified in the 751 // constructor. We don't support keys or values that are more aligned than a 752 // pointer. 753 char data[RootDataSize]; 754 755 // Tree height. 756 // 0: Leaves in root. 757 // 1: Root points to leaf. 758 // 2: root->branch->leaf ... 759 unsigned height; 760 761 // Number of entries in the root node. 762 unsigned rootSize; 763 764 // Allocator used for creating external nodes. 765 Allocator &allocator; 766 767 /// dataAs - Represent data as a node type without breaking aliasing rules. 768 template <typename T> 769 T &dataAs() const { 770 union { 771 const char *d; 772 T *t; 773 } u; 774 u.d = data; 775 return *u.t; 776 } 777 778 const RootLeaf &rootLeaf() const { 779 assert(!branched() && "Cannot acces leaf data in branched root"); 780 return dataAs<RootLeaf>(); 781 } 782 RootLeaf &rootLeaf() { 783 assert(!branched() && "Cannot acces leaf data in branched root"); 784 return dataAs<RootLeaf>(); 785 } 786 RootBranchData &rootBranchData() const { 787 assert(branched() && "Cannot access branch data in non-branched root"); 788 return dataAs<RootBranchData>(); 789 } 790 RootBranchData &rootBranchData() { 791 assert(branched() && "Cannot access branch data in non-branched root"); 792 return dataAs<RootBranchData>(); 793 } 794 const RootBranch &rootBranch() const { return rootBranchData().node; } 795 RootBranch &rootBranch() { return rootBranchData().node; } 796 KeyT rootBranchStart() const { return rootBranchData().start; } 797 KeyT &rootBranchStart() { return rootBranchData().start; } 798 799 Leaf *allocLeaf() { 800 return new(allocator.template Allocate<Leaf>()) Leaf(); 801 } 802 void deleteLeaf(Leaf *P) { 803 P->~Leaf(); 804 allocator.Deallocate(P); 805 } 806 807 Branch *allocBranch() { 808 return new(allocator.template Allocate<Branch>()) Branch(); 809 } 810 void deleteBranch(Branch *P) { 811 P->~Branch(); 812 allocator.Deallocate(P); 813 } 814 815 816 IdxPair branchRoot(unsigned Position); 817 IdxPair splitRoot(unsigned Position); 818 819 void switchRootToBranch() { 820 rootLeaf().~RootLeaf(); 821 height = 1; 822 new (&rootBranchData()) RootBranchData(); 823 } 824 825 void switchRootToLeaf() { 826 rootBranchData().~RootBranchData(); 827 height = 0; 828 new(&rootLeaf()) RootLeaf(); 829 } 830 831 bool branched() const { return height > 0; } 832 833 ValT treeSafeLookup(KeyT x, ValT NotFound) const; 834 void visitNodes(void (IntervalMap::*f)(IntervalMapImpl::NodeRef, 835 unsigned Level)); 836 void deleteNode(IntervalMapImpl::NodeRef Node, unsigned Level); 837 838public: 839 explicit IntervalMap(Allocator &a) : height(0), rootSize(0), allocator(a) { 840 assert((uintptr_t(data) & (alignOf<RootLeaf>() - 1)) == 0 && 841 "Insufficient alignment"); 842 new(&rootLeaf()) RootLeaf(); 843 } 844 845 ~IntervalMap() { 846 clear(); 847 rootLeaf().~RootLeaf(); 848 } 849 850 /// empty - Return true when no intervals are mapped. 851 bool empty() const { 852 return rootSize == 0; 853 } 854 855 /// start - Return the smallest mapped key in a non-empty map. 856 KeyT start() const { 857 assert(!empty() && "Empty IntervalMap has no start"); 858 return !branched() ? rootLeaf().start(0) : rootBranchStart(); 859 } 860 861 /// stop - Return the largest mapped key in a non-empty map. 862 KeyT stop() const { 863 assert(!empty() && "Empty IntervalMap has no stop"); 864 return !branched() ? rootLeaf().stop(rootSize - 1) : 865 rootBranch().stop(rootSize - 1); 866 } 867 868 /// lookup - Return the mapped value at x or NotFound. 869 ValT lookup(KeyT x, ValT NotFound = ValT()) const { 870 if (empty() || Traits::startLess(x, start()) || Traits::stopLess(stop(), x)) 871 return NotFound; 872 return branched() ? treeSafeLookup(x, NotFound) : 873 rootLeaf().safeLookup(x, NotFound); 874 } 875 876 /// insert - Add a mapping of [a;b] to y, coalesce with adjacent intervals. 877 /// It is assumed that no key in the interval is mapped to another value, but 878 /// overlapping intervals already mapped to y will be coalesced. 879 void insert(KeyT a, KeyT b, ValT y) { 880 find(a).insert(a, b, y); 881 } 882 883 /// clear - Remove all entries. 884 void clear(); 885 886 class const_iterator; 887 class iterator; 888 friend class const_iterator; 889 friend class iterator; 890 891 const_iterator begin() const { 892 iterator I(*this); 893 I.goToBegin(); 894 return I; 895 } 896 897 iterator begin() { 898 iterator I(*this); 899 I.goToBegin(); 900 return I; 901 } 902 903 const_iterator end() const { 904 iterator I(*this); 905 I.goToEnd(); 906 return I; 907 } 908 909 iterator end() { 910 iterator I(*this); 911 I.goToEnd(); 912 return I; 913 } 914 915 /// find - Return an iterator pointing to the first interval ending at or 916 /// after x, or end(). 917 const_iterator find(KeyT x) const { 918 iterator I(*this); 919 I.find(x); 920 return I; 921 } 922 923 iterator find(KeyT x) { 924 iterator I(*this); 925 I.find(x); 926 return I; 927 } 928 929#ifndef NDEBUG 930 void dump(); 931 void dumpNode(IntervalMapImpl::NodeRef Node, unsigned Height); 932#endif 933}; 934 935/// treeSafeLookup - Return the mapped value at x or NotFound, assuming a 936/// branched root. 937template <typename KeyT, typename ValT, unsigned N, typename Traits> 938ValT IntervalMap<KeyT, ValT, N, Traits>:: 939treeSafeLookup(KeyT x, ValT NotFound) const { 940 assert(branched() && "treeLookup assumes a branched root"); 941 942 IntervalMapImpl::NodeRef NR = rootBranch().safeLookup(x); 943 for (unsigned h = height-1; h; --h) 944 NR = NR.get<Branch>().safeLookup(x); 945 return NR.get<Leaf>().safeLookup(x, NotFound); 946} 947 948 949// branchRoot - Switch from a leaf root to a branched root. 950// Return the new (root offset, node offset) corresponding to Position. 951template <typename KeyT, typename ValT, unsigned N, typename Traits> 952IntervalMapImpl::IdxPair IntervalMap<KeyT, ValT, N, Traits>:: 953branchRoot(unsigned Position) { 954 using namespace IntervalMapImpl; 955 // How many external leaf nodes to hold RootLeaf+1? 956 const unsigned Nodes = RootLeaf::Capacity / Leaf::Capacity + 1; 957 958 // Compute element distribution among new nodes. 959 unsigned size[Nodes]; 960 IdxPair NewOffset(0, Position); 961 962 // Is is very common for the root node to be smaller than external nodes. 963 if (Nodes == 1) 964 size[0] = rootSize; 965 else 966 NewOffset = distribute(Nodes, rootSize, Leaf::Capacity, NULL, size, 967 Position, true); 968 969 // Allocate new nodes. 970 unsigned pos = 0; 971 NodeRef node[Nodes]; 972 for (unsigned n = 0; n != Nodes; ++n) { 973 node[n] = NodeRef(allocLeaf(), size[n]); 974 node[n].template get<Leaf>().copy(rootLeaf(), pos, 0, size[n]); 975 pos += size[n]; 976 } 977 978 // Destroy the old leaf node, construct branch node instead. 979 switchRootToBranch(); 980 for (unsigned n = 0; n != Nodes; ++n) { 981 rootBranch().stop(n) = node[n].template get<Leaf>().stop(size[n]-1); 982 rootBranch().subtree(n) = node[n]; 983 } 984 rootBranchStart() = node[0].template get<Leaf>().start(0); 985 rootSize = Nodes; 986 return NewOffset; 987} 988 989// splitRoot - Split the current BranchRoot into multiple Branch nodes. 990// Return the new (root offset, node offset) corresponding to Position. 991template <typename KeyT, typename ValT, unsigned N, typename Traits> 992IntervalMapImpl::IdxPair IntervalMap<KeyT, ValT, N, Traits>:: 993splitRoot(unsigned Position) { 994 using namespace IntervalMapImpl; 995 // How many external leaf nodes to hold RootBranch+1? 996 const unsigned Nodes = RootBranch::Capacity / Branch::Capacity + 1; 997 998 // Compute element distribution among new nodes. 999 unsigned Size[Nodes]; 1000 IdxPair NewOffset(0, Position); 1001 1002 // Is is very common for the root node to be smaller than external nodes. 1003 if (Nodes == 1) 1004 Size[0] = rootSize; 1005 else 1006 NewOffset = distribute(Nodes, rootSize, Leaf::Capacity, NULL, Size, 1007 Position, true); 1008 1009 // Allocate new nodes. 1010 unsigned Pos = 0; 1011 NodeRef Node[Nodes]; 1012 for (unsigned n = 0; n != Nodes; ++n) { 1013 Node[n] = NodeRef(allocBranch(), Size[n]); 1014 Node[n].template get<Branch>().copy(rootBranch(), Pos, 0, Size[n]); 1015 Pos += Size[n]; 1016 } 1017 1018 for (unsigned n = 0; n != Nodes; ++n) { 1019 rootBranch().stop(n) = Node[n].template get<Branch>().stop(Size[n]-1); 1020 rootBranch().subtree(n) = Node[n]; 1021 } 1022 rootSize = Nodes; 1023 return NewOffset; 1024} 1025 1026/// visitNodes - Visit each external node. 1027template <typename KeyT, typename ValT, unsigned N, typename Traits> 1028void IntervalMap<KeyT, ValT, N, Traits>:: 1029visitNodes(void (IntervalMap::*f)(IntervalMapImpl::NodeRef, unsigned Height)) { 1030 if (!branched()) 1031 return; 1032 SmallVector<IntervalMapImpl::NodeRef, 4> Refs, NextRefs; 1033 1034 // Collect level 0 nodes from the root. 1035 for (unsigned i = 0; i != rootSize; ++i) 1036 Refs.push_back(rootBranch().subtree(i)); 1037 1038 // Visit all branch nodes. 1039 for (unsigned h = height - 1; h; --h) { 1040 for (unsigned i = 0, e = Refs.size(); i != e; ++i) { 1041 for (unsigned j = 0, s = Refs[i].size(); j != s; ++j) 1042 NextRefs.push_back(Refs[i].subtree(j)); 1043 (this->*f)(Refs[i], h); 1044 } 1045 Refs.clear(); 1046 Refs.swap(NextRefs); 1047 } 1048 1049 // Visit all leaf nodes. 1050 for (unsigned i = 0, e = Refs.size(); i != e; ++i) 1051 (this->*f)(Refs[i], 0); 1052} 1053 1054template <typename KeyT, typename ValT, unsigned N, typename Traits> 1055void IntervalMap<KeyT, ValT, N, Traits>:: 1056deleteNode(IntervalMapImpl::NodeRef Node, unsigned Level) { 1057 if (Level) 1058 deleteBranch(&Node.get<Branch>()); 1059 else 1060 deleteLeaf(&Node.get<Leaf>()); 1061} 1062 1063template <typename KeyT, typename ValT, unsigned N, typename Traits> 1064void IntervalMap<KeyT, ValT, N, Traits>:: 1065clear() { 1066 if (branched()) { 1067 visitNodes(&IntervalMap::deleteNode); 1068 switchRootToLeaf(); 1069 } 1070 rootSize = 0; 1071} 1072 1073#ifndef NDEBUG 1074template <typename KeyT, typename ValT, unsigned N, typename Traits> 1075void IntervalMap<KeyT, ValT, N, Traits>:: 1076dumpNode(IntervalMapImpl::NodeRef Node, unsigned Height) { 1077 if (Height) 1078 Node.get<Branch>().dump(Node.size()); 1079 else 1080 Node.get<Leaf>().dump(Node.size()); 1081} 1082 1083template <typename KeyT, typename ValT, unsigned N, typename Traits> 1084void IntervalMap<KeyT, ValT, N, Traits>:: 1085dump() { 1086 errs() << "digraph {\n"; 1087 if (branched()) 1088 rootBranch().dump(rootSize); 1089 else 1090 rootLeaf().dump(rootSize); 1091 visitNodes(&IntervalMap::dumpNode); 1092 errs() << "}\n"; 1093} 1094#endif 1095 1096//===----------------------------------------------------------------------===// 1097//--- const_iterator ----// 1098//===----------------------------------------------------------------------===// 1099 1100template <typename KeyT, typename ValT, unsigned N, typename Traits> 1101class IntervalMap<KeyT, ValT, N, Traits>::const_iterator : 1102 public std::iterator<std::bidirectional_iterator_tag, ValT> { 1103protected: 1104 friend class IntervalMap; 1105 typedef std::pair<IntervalMapImpl::NodeRef, unsigned> PathEntry; 1106 typedef SmallVector<PathEntry, 4> Path; 1107 1108 // The map referred to. 1109 IntervalMap *map; 1110 1111 // The offset into map's root node. 1112 unsigned rootOffset; 1113 1114 // We store a full path from the root to the current position. 1115 // 1116 // When rootOffset == map->rootSize, we are at end() and path() is empty. 1117 // Otherwise, when branched these conditions hold: 1118 // 1119 // 1. path.front().first == rootBranch().subtree(rootOffset) 1120 // 2. path[i].first == path[i-1].first.subtree(path[i-1].second) 1121 // 3. path.size() == map->height. 1122 // 1123 // Thus, path.back() always refers to the current leaf node unless the root is 1124 // unbranched. 1125 // 1126 // The path may be partially filled, but never between iterator calls. 1127 Path path; 1128 1129 explicit const_iterator(IntervalMap &map) 1130 : map(&map), rootOffset(map.rootSize) {} 1131 1132 bool branched() const { 1133 assert(map && "Invalid iterator"); 1134 return map->branched(); 1135 } 1136 1137 IntervalMapImpl::NodeRef pathNode(unsigned h) const { return path[h].first; } 1138 IntervalMapImpl::NodeRef &pathNode(unsigned h) { return path[h].first; } 1139 unsigned pathOffset(unsigned h) const { return path[h].second; } 1140 unsigned &pathOffset(unsigned h) { return path[h].second; } 1141 1142 Leaf &treeLeaf() const { 1143 assert(branched() && path.size() == map->height); 1144 return path.back().first.get<Leaf>(); 1145 } 1146 unsigned treeLeafSize() const { 1147 assert(branched() && path.size() == map->height); 1148 return path.back().first.size(); 1149 } 1150 unsigned &treeLeafOffset() { 1151 assert(branched() && path.size() == map->height); 1152 return path.back().second; 1153 } 1154 unsigned treeLeafOffset() const { 1155 assert(branched() && path.size() == map->height); 1156 return path.back().second; 1157 } 1158 1159 // Get the next node ptr for an incomplete path. 1160 IntervalMapImpl::NodeRef pathNextDown() { 1161 assert(path.size() < map->height && "Path is already complete"); 1162 1163 if (path.empty()) 1164 return map->rootBranch().subtree(rootOffset); 1165 else 1166 return path.back().first.subtree(path.back().second); 1167 } 1168 1169 void pathFillLeft(); 1170 void pathFillFind(KeyT x); 1171 void pathFillRight(); 1172 1173 IntervalMapImpl::NodeRef leftSibling(unsigned level) const; 1174 IntervalMapImpl::NodeRef rightSibling(unsigned level) const; 1175 1176 void treeIncrement(); 1177 void treeDecrement(); 1178 void treeFind(KeyT x); 1179 1180public: 1181 /// valid - Return true if the current position is valid, false for end(). 1182 bool valid() const { 1183 assert(map && "Invalid iterator"); 1184 return rootOffset < map->rootSize; 1185 } 1186 1187 /// start - Return the beginning of the current interval. 1188 const KeyT &start() const { 1189 assert(valid() && "Cannot access invalid iterator"); 1190 return branched() ? treeLeaf().start(treeLeafOffset()) : 1191 map->rootLeaf().start(rootOffset); 1192 } 1193 1194 /// stop - Return the end of the current interval. 1195 const KeyT &stop() const { 1196 assert(valid() && "Cannot access invalid iterator"); 1197 return branched() ? treeLeaf().stop(treeLeafOffset()) : 1198 map->rootLeaf().stop(rootOffset); 1199 } 1200 1201 /// value - Return the mapped value at the current interval. 1202 const ValT &value() const { 1203 assert(valid() && "Cannot access invalid iterator"); 1204 return branched() ? treeLeaf().value(treeLeafOffset()) : 1205 map->rootLeaf().value(rootOffset); 1206 } 1207 1208 const ValT &operator*() const { 1209 return value(); 1210 } 1211 1212 bool operator==(const const_iterator &RHS) const { 1213 assert(map == RHS.map && "Cannot compare iterators from different maps"); 1214 return rootOffset == RHS.rootOffset && 1215 (!valid() || !branched() || path.back() == RHS.path.back()); 1216 } 1217 1218 bool operator!=(const const_iterator &RHS) const { 1219 return !operator==(RHS); 1220 } 1221 1222 /// goToBegin - Move to the first interval in map. 1223 void goToBegin() { 1224 rootOffset = 0; 1225 path.clear(); 1226 if (branched()) 1227 pathFillLeft(); 1228 } 1229 1230 /// goToEnd - Move beyond the last interval in map. 1231 void goToEnd() { 1232 rootOffset = map->rootSize; 1233 path.clear(); 1234 } 1235 1236 /// preincrement - move to the next interval. 1237 const_iterator &operator++() { 1238 assert(valid() && "Cannot increment end()"); 1239 if (!branched()) 1240 ++rootOffset; 1241 else if (treeLeafOffset() != treeLeafSize() - 1) 1242 ++treeLeafOffset(); 1243 else 1244 treeIncrement(); 1245 return *this; 1246 } 1247 1248 /// postincrement - Dont do that! 1249 const_iterator operator++(int) { 1250 const_iterator tmp = *this; 1251 operator++(); 1252 return tmp; 1253 } 1254 1255 /// predecrement - move to the previous interval. 1256 const_iterator &operator--() { 1257 if (!branched()) { 1258 assert(rootOffset && "Cannot decrement begin()"); 1259 --rootOffset; 1260 } else if (valid() && treeLeafOffset()) 1261 --treeLeafOffset(); 1262 else 1263 treeDecrement(); 1264 return *this; 1265 } 1266 1267 /// postdecrement - Dont do that! 1268 const_iterator operator--(int) { 1269 const_iterator tmp = *this; 1270 operator--(); 1271 return tmp; 1272 } 1273 1274 /// find - Move to the first interval with stop >= x, or end(). 1275 /// This is a full search from the root, the current position is ignored. 1276 void find(KeyT x) { 1277 if (branched()) 1278 treeFind(x); 1279 else 1280 rootOffset = map->rootLeaf().findFrom(0, map->rootSize, x); 1281 } 1282 1283 /// advanceTo - Move to the first interval with stop >= x, or end(). 1284 /// The search is started from the current position, and no earlier positions 1285 /// can be found. This is much faster than find() for small moves. 1286 void advanceTo(KeyT x) { 1287 if (branched()) 1288 treeAdvanceTo(x); 1289 else 1290 rootOffset = map->rootLeaf().findFrom(rootOffset, map->rootSize, x); 1291 } 1292 1293}; 1294 1295// pathFillLeft - Complete path by following left-most branches. 1296template <typename KeyT, typename ValT, unsigned N, typename Traits> 1297void IntervalMap<KeyT, ValT, N, Traits>:: 1298const_iterator::pathFillLeft() { 1299 IntervalMapImpl::NodeRef NR = pathNextDown(); 1300 for (unsigned i = map->height - path.size() - 1; i; --i) { 1301 path.push_back(PathEntry(NR, 0)); 1302 NR = NR.subtree(0); 1303 } 1304 path.push_back(PathEntry(NR, 0)); 1305} 1306 1307// pathFillFind - Complete path by searching for x. 1308template <typename KeyT, typename ValT, unsigned N, typename Traits> 1309void IntervalMap<KeyT, ValT, N, Traits>:: 1310const_iterator::pathFillFind(KeyT x) { 1311 IntervalMapImpl::NodeRef NR = pathNextDown(); 1312 for (unsigned i = map->height - path.size() - 1; i; --i) { 1313 unsigned p = NR.get<Branch>().safeFind(0, x); 1314 path.push_back(PathEntry(NR, p)); 1315 NR = NR.subtree(p); 1316 } 1317 path.push_back(PathEntry(NR, NR.get<Leaf>().safeFind(0, x))); 1318} 1319 1320// pathFillRight - Complete path by adding rightmost entries. 1321template <typename KeyT, typename ValT, unsigned N, typename Traits> 1322void IntervalMap<KeyT, ValT, N, Traits>:: 1323const_iterator::pathFillRight() { 1324 IntervalMapImpl::NodeRef NR = pathNextDown(); 1325 for (unsigned i = map->height - path.size() - 1; i; --i) { 1326 unsigned p = NR.size() - 1; 1327 path.push_back(PathEntry(NR, p)); 1328 NR = NR.subtree(p); 1329 } 1330 path.push_back(PathEntry(NR, NR.size() - 1)); 1331} 1332 1333/// leftSibling - find the left sibling node to path[level]. 1334/// @param level 0 is just below the root, map->height - 1 for the leaves. 1335/// @return The left sibling NodeRef, or NULL. 1336template <typename KeyT, typename ValT, unsigned N, typename Traits> 1337IntervalMapImpl::NodeRef IntervalMap<KeyT, ValT, N, Traits>:: 1338const_iterator::leftSibling(unsigned level) const { 1339 using namespace IntervalMapImpl; 1340 assert(branched() && "Not at a branched node"); 1341 assert(level <= path.size() && "Bad level"); 1342 1343 // Go up the tree until we can go left. 1344 unsigned h = level; 1345 while (h && pathOffset(h - 1) == 0) 1346 --h; 1347 1348 // We are at the first leaf node, no left sibling. 1349 if (!h && rootOffset == 0) 1350 return NodeRef(); 1351 1352 // NR is the subtree containing our left sibling. 1353 NodeRef NR = h ? 1354 pathNode(h - 1).subtree(pathOffset(h - 1) - 1) : 1355 map->rootBranch().subtree(rootOffset - 1); 1356 1357 // Keep right all the way down. 1358 for (; h != level; ++h) 1359 NR = NR.subtree(NR.size() - 1); 1360 return NR; 1361} 1362 1363/// rightSibling - find the right sibling node to path[level]. 1364/// @param level 0 is just below the root, map->height - 1 for the leaves. 1365/// @return The right sibling NodeRef, or NULL. 1366template <typename KeyT, typename ValT, unsigned N, typename Traits> 1367IntervalMapImpl::NodeRef IntervalMap<KeyT, ValT, N, Traits>:: 1368const_iterator::rightSibling(unsigned level) const { 1369 using namespace IntervalMapImpl; 1370 assert(branched() && "Not at a branched node"); 1371 assert(level <= this->path.size() && "Bad level"); 1372 1373 // Go up the tree until we can go right. 1374 unsigned h = level; 1375 while (h && pathOffset(h - 1) == pathNode(h - 1).size() - 1) 1376 --h; 1377 1378 // We are at the last leaf node, no right sibling. 1379 if (!h && rootOffset == map->rootSize - 1) 1380 return NodeRef(); 1381 1382 // NR is the subtree containing our right sibling. 1383 NodeRef NR = h ? 1384 pathNode(h - 1).subtree(pathOffset(h - 1) + 1) : 1385 map->rootBranch().subtree(rootOffset + 1); 1386 1387 // Keep left all the way down. 1388 for (; h != level; ++h) 1389 NR = NR.subtree(0); 1390 return NR; 1391} 1392 1393// treeIncrement - Move to the beginning of the next leaf node. 1394template <typename KeyT, typename ValT, unsigned N, typename Traits> 1395void IntervalMap<KeyT, ValT, N, Traits>:: 1396const_iterator::treeIncrement() { 1397 assert(branched() && "treeIncrement is not for small maps"); 1398 assert(path.size() == map->height && "inconsistent iterator"); 1399 do path.pop_back(); 1400 while (!path.empty() && path.back().second == path.back().first.size() - 1); 1401 if (path.empty()) { 1402 ++rootOffset; 1403 if (!valid()) 1404 return; 1405 } else 1406 ++path.back().second; 1407 pathFillLeft(); 1408} 1409 1410// treeDecrement - Move to the end of the previous leaf node. 1411template <typename KeyT, typename ValT, unsigned N, typename Traits> 1412void IntervalMap<KeyT, ValT, N, Traits>:: 1413const_iterator::treeDecrement() { 1414 assert(branched() && "treeDecrement is not for small maps"); 1415 if (valid()) { 1416 assert(path.size() == map->height && "inconsistent iterator"); 1417 do path.pop_back(); 1418 while (!path.empty() && path.back().second == 0); 1419 } 1420 if (path.empty()) { 1421 assert(rootOffset && "cannot treeDecrement() on begin()"); 1422 --rootOffset; 1423 } else 1424 --path.back().second; 1425 pathFillRight(); 1426} 1427 1428// treeFind - Find in a branched tree. 1429template <typename KeyT, typename ValT, unsigned N, typename Traits> 1430void IntervalMap<KeyT, ValT, N, Traits>:: 1431const_iterator::treeFind(KeyT x) { 1432 path.clear(); 1433 rootOffset = map->rootBranch().findFrom(0, map->rootSize, x); 1434 if (valid()) 1435 pathFillFind(x); 1436} 1437 1438 1439//===----------------------------------------------------------------------===// 1440//--- iterator ----// 1441//===----------------------------------------------------------------------===// 1442 1443namespace IntervalMapImpl { 1444 1445 /// distribute - Compute a new distribution of node elements after an overflow 1446 /// or underflow. Reserve space for a new element at Position, and compute the 1447 /// node that will hold Position after redistributing node elements. 1448 /// 1449 /// It is required that 1450 /// 1451 /// Elements == sum(CurSize), and 1452 /// Elements + Grow <= Nodes * Capacity. 1453 /// 1454 /// NewSize[] will be filled in such that: 1455 /// 1456 /// sum(NewSize) == Elements, and 1457 /// NewSize[i] <= Capacity. 1458 /// 1459 /// The returned index is the node where Position will go, so: 1460 /// 1461 /// sum(NewSize[0..idx-1]) <= Position 1462 /// sum(NewSize[0..idx]) >= Position 1463 /// 1464 /// The last equality, sum(NewSize[0..idx]) == Position, can only happen when 1465 /// Grow is set and NewSize[idx] == Capacity-1. The index points to the node 1466 /// before the one holding the Position'th element where there is room for an 1467 /// insertion. 1468 /// 1469 /// @param Nodes The number of nodes. 1470 /// @param Elements Total elements in all nodes. 1471 /// @param Capacity The capacity of each node. 1472 /// @param CurSize Array[Nodes] of current node sizes, or NULL. 1473 /// @param NewSize Array[Nodes] to receive the new node sizes. 1474 /// @param Position Insert position. 1475 /// @param Grow Reserve space for a new element at Position. 1476 /// @return (node, offset) for Position. 1477 IdxPair distribute(unsigned Nodes, unsigned Elements, unsigned Capacity, 1478 const unsigned *CurSize, unsigned NewSize[], 1479 unsigned Position, bool Grow); 1480 1481} 1482 1483template <typename KeyT, typename ValT, unsigned N, typename Traits> 1484class IntervalMap<KeyT, ValT, N, Traits>::iterator : public const_iterator { 1485 friend class IntervalMap; 1486 typedef IntervalMapImpl::IdxPair IdxPair; 1487 1488 explicit iterator(IntervalMap &map) : const_iterator(map) {} 1489 1490 void setNodeSize(unsigned Level, unsigned Size); 1491 void setNodeStop(unsigned Level, KeyT Stop); 1492 void insertNode(unsigned Level, IntervalMapImpl::NodeRef Node, KeyT Stop); 1493 void overflowLeaf(); 1494 void treeInsert(KeyT a, KeyT b, ValT y); 1495 1496public: 1497 /// insert - Insert mapping [a;b] -> y before the current position. 1498 void insert(KeyT a, KeyT b, ValT y); 1499 1500}; 1501 1502/// setNodeSize - Set the size of the node at path[level], updating both path 1503/// and the real tree. 1504/// @param level 0 is just below the root, map->height - 1 for the leaves. 1505/// @param size New node size. 1506template <typename KeyT, typename ValT, unsigned N, typename Traits> 1507void IntervalMap<KeyT, ValT, N, Traits>:: 1508iterator::setNodeSize(unsigned Level, unsigned Size) { 1509 this->pathNode(Level).setSize(Size); 1510 if (Level) 1511 this->pathNode(Level-1).subtree(this->pathOffset(Level-1)).setSize(Size); 1512 else 1513 this->map->rootBranch().subtree(this->rootOffset).setSize(Size); 1514} 1515 1516/// setNodeStop - Update the stop key of the current node at level and above. 1517template <typename KeyT, typename ValT, unsigned N, typename Traits> 1518void IntervalMap<KeyT, ValT, N, Traits>:: 1519iterator::setNodeStop(unsigned Level, KeyT Stop) { 1520 while (Level--) { 1521 this->pathNode(Level).template get<Branch>() 1522 .stop(this->pathOffset(Level)) = Stop; 1523 if (this->pathOffset(Level) != this->pathNode(Level).size() - 1) 1524 return; 1525 } 1526 this->map->rootBranch().stop(this->rootOffset) = Stop; 1527} 1528 1529/// insertNode - insert a node before the current path at level. 1530/// Leave the current path pointing at the new node. 1531template <typename KeyT, typename ValT, unsigned N, typename Traits> 1532void IntervalMap<KeyT, ValT, N, Traits>:: 1533iterator::insertNode(unsigned Level, IntervalMapImpl::NodeRef Node, KeyT Stop) { 1534 if (!Level) { 1535 // Insert into the root branch node. 1536 IntervalMap &IM = *this->map; 1537 if (IM.rootSize < RootBranch::Capacity) { 1538 IM.rootBranch().insert(this->rootOffset, IM.rootSize, Node, Stop); 1539 ++IM.rootSize; 1540 return; 1541 } 1542 1543 // We need to split the root while keeping our position. 1544 IdxPair Offset = IM.splitRoot(this->rootOffset); 1545 this->rootOffset = Offset.first; 1546 this->path.insert(this->path.begin(),std::make_pair( 1547 this->map->rootBranch().subtree(Offset.first), Offset.second)); 1548 Level = 1; 1549 } 1550 1551 // When inserting before end(), make sure we have a valid path. 1552 if (!this->valid()) { 1553 this->treeDecrement(); 1554 ++this->pathOffset(Level-1); 1555 } 1556 1557 // Insert into the branch node at level-1. 1558 IntervalMapImpl::NodeRef NR = this->pathNode(Level-1); 1559 unsigned Offset = this->pathOffset(Level-1); 1560 assert(NR.size() < Branch::Capacity && "Branch overflow"); 1561 NR.get<Branch>().insert(Offset, NR.size(), Node, Stop); 1562 setNodeSize(Level - 1, NR.size() + 1); 1563} 1564 1565// insert 1566template <typename KeyT, typename ValT, unsigned N, typename Traits> 1567void IntervalMap<KeyT, ValT, N, Traits>:: 1568iterator::insert(KeyT a, KeyT b, ValT y) { 1569 if (this->branched()) 1570 return treeInsert(a, b, y); 1571 IdxPair IP = this->map->rootLeaf().insertFrom(this->rootOffset, 1572 this->map->rootSize, 1573 a, b, y); 1574 if (IP.second <= RootLeaf::Capacity) { 1575 this->rootOffset = IP.first; 1576 this->map->rootSize = IP.second; 1577 return; 1578 } 1579 IdxPair Offset = this->map->branchRoot(this->rootOffset); 1580 this->rootOffset = Offset.first; 1581 this->path.push_back(std::make_pair( 1582 this->map->rootBranch().subtree(Offset.first), Offset.second)); 1583 treeInsert(a, b, y); 1584} 1585 1586 1587template <typename KeyT, typename ValT, unsigned N, typename Traits> 1588void IntervalMap<KeyT, ValT, N, Traits>:: 1589iterator::treeInsert(KeyT a, KeyT b, ValT y) { 1590 if (!this->valid()) { 1591 // end() has an empty path. Go back to the last leaf node and use an 1592 // invalid offset instead. 1593 this->treeDecrement(); 1594 ++this->treeLeafOffset(); 1595 } 1596 IdxPair IP = this->treeLeaf().insertFrom(this->treeLeafOffset(), 1597 this->treeLeafSize(), a, b, y); 1598 this->treeLeafOffset() = IP.first; 1599 if (IP.second <= Leaf::Capacity) { 1600 setNodeSize(this->map->height - 1, IP.second); 1601 if (IP.first == IP.second - 1) 1602 setNodeStop(this->map->height - 1, this->treeLeaf().stop(IP.first)); 1603 return; 1604 } 1605 // Leaf node has no space. 1606 overflowLeaf(); 1607 IP = this->treeLeaf().insertFrom(this->treeLeafOffset(), 1608 this->treeLeafSize(), a, b, y); 1609 this->treeLeafOffset() = IP.first; 1610 setNodeSize(this->map->height-1, IP.second); 1611 if (IP.first == IP.second - 1) 1612 setNodeStop(this->map->height - 1, this->treeLeaf().stop(IP.first)); 1613 1614 // FIXME: Handle cross-node coalescing. 1615} 1616 1617// overflowLeaf - Distribute entries of the current leaf node evenly among 1618// its siblings and ensure that the current node is not full. 1619// This may require allocating a new node. 1620template <typename KeyT, typename ValT, unsigned N, typename Traits> 1621void IntervalMap<KeyT, ValT, N, Traits>:: 1622iterator::overflowLeaf() { 1623 using namespace IntervalMapImpl; 1624 unsigned CurSize[4]; 1625 Leaf *Node[4]; 1626 unsigned Nodes = 0; 1627 unsigned Elements = 0; 1628 unsigned Offset = this->treeLeafOffset(); 1629 1630 // Do we have a left sibling? 1631 NodeRef LeftSib = this->leftSibling(this->map->height-1); 1632 if (LeftSib) { 1633 Offset += Elements = CurSize[Nodes] = LeftSib.size(); 1634 Node[Nodes++] = &LeftSib.get<Leaf>(); 1635 } 1636 1637 // Current leaf node. 1638 Elements += CurSize[Nodes] = this->treeLeafSize(); 1639 Node[Nodes++] = &this->treeLeaf(); 1640 1641 // Do we have a right sibling? 1642 NodeRef RightSib = this->rightSibling(this->map->height-1); 1643 if (RightSib) { 1644 Offset += Elements = CurSize[Nodes] = RightSib.size(); 1645 Node[Nodes++] = &RightSib.get<Leaf>(); 1646 } 1647 1648 // Do we need to allocate a new node? 1649 unsigned NewNode = 0; 1650 if (Elements + 1 > Nodes * Leaf::Capacity) { 1651 // Insert NewNode at the penultimate position, or after a single node. 1652 NewNode = Nodes == 1 ? 1 : Nodes - 1; 1653 CurSize[Nodes] = CurSize[NewNode]; 1654 Node[Nodes] = Node[NewNode]; 1655 CurSize[NewNode] = 0; 1656 Node[NewNode] = this->map->allocLeaf(); 1657 ++Nodes; 1658 } 1659 1660 // Compute the new element distribution. 1661 unsigned NewSize[4]; 1662 IdxPair NewOffset = distribute(Nodes, Elements, Leaf::Capacity, 1663 CurSize, NewSize, Offset, true); 1664 1665 // Move current location to the leftmost node. 1666 if (LeftSib) 1667 this->treeDecrement(); 1668 1669 // Move elements right. 1670 for (int n = Nodes - 1; n; --n) { 1671 if (CurSize[n] == NewSize[n]) 1672 continue; 1673 for (int m = n - 1; m != -1; --m) { 1674 int d = Node[n]->adjustFromLeftSib(CurSize[n], *Node[m], CurSize[m], 1675 NewSize[n] - CurSize[n]); 1676 CurSize[m] -= d; 1677 CurSize[n] += d; 1678 // Keep going if the current node was exhausted. 1679 if (CurSize[n] >= NewSize[n]) 1680 break; 1681 } 1682 } 1683 1684 // Move elements left. 1685 for (unsigned n = 0; n != Nodes - 1; ++n) { 1686 if (CurSize[n] == NewSize[n]) 1687 continue; 1688 for (unsigned m = n + 1; m != Nodes; ++m) { 1689 int d = Node[m]->adjustFromLeftSib(CurSize[m], *Node[n], CurSize[n], 1690 CurSize[n] - NewSize[n]); 1691 CurSize[m] += d; 1692 CurSize[n] -= d; 1693 // Keep going if the current node was exhausted. 1694 if (CurSize[n] >= NewSize[n]) 1695 break; 1696 } 1697 } 1698 1699#ifndef NDEBUG 1700 for (unsigned n = 0; n != Nodes; n++) 1701 assert(CurSize[n] == NewSize[n] && "Insufficient element shuffle"); 1702#endif 1703 1704 // Elements have been rearranged, now update node sizes and stops. 1705 unsigned Pos = 0; 1706 for (;;) { 1707 KeyT Stop = Node[Pos]->stop(NewSize[Pos]-1); 1708 if (NewNode && Pos == NewNode) 1709 insertNode(this->map->height - 1, NodeRef(Node[Pos], NewSize[Pos]), Stop); 1710 else { 1711 setNodeSize(this->map->height - 1, NewSize[Pos]); 1712 setNodeStop(this->map->height - 1, Stop); 1713 } 1714 if (Pos + 1 == Nodes) 1715 break; 1716 this->treeIncrement(); 1717 ++Pos; 1718 } 1719 1720 // Where was I? Find NewOffset. 1721 while(Pos != NewOffset.first) { 1722 this->treeDecrement(); 1723 --Pos; 1724 } 1725 this->treeLeafOffset() = NewOffset.second; 1726} 1727 1728} // namespace llvm 1729 1730#endif 1731