IntervalMap.h revision 655fbb4f9b46ea93eddf0815eaed0020e9347416
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 (key,value) pairs. 174// Leaves store ((KeyT, KeyT), ValT) pairs, branches use (KeyT, NodeRef). 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// KT VT N Waste Used by 188// 4 4 24 0 Branch<4> (32-bit pointers) 189// 4 8 16 0 Branch<4> 190// 8 4 16 0 Leaf<4,4> 191// 8 8 12 0 Leaf<4,8>, Branch<8> 192// 16 4 9 12 Leaf<8,4> 193// 16 8 8 0 Leaf<8,8> 194// 195//===----------------------------------------------------------------------===// 196 197template <typename KT, typename VT, unsigned N> 198class NodeBase { 199public: 200 enum { Capacity = N }; 201 202 KT key[N]; 203 VT val[N]; 204 205 /// copy - Copy elements from another node. 206 /// @param Other Node elements are copied from. 207 /// @param i Beginning of the source range in other. 208 /// @param j Beginning of the destination range in this. 209 /// @param Count Number of elements to copy. 210 template <unsigned M> 211 void copy(const NodeBase<KT, VT, M> &Other, unsigned i, 212 unsigned j, unsigned Count) { 213 assert(i + Count <= M && "Invalid source range"); 214 assert(j + Count <= N && "Invalid dest range"); 215 std::copy(Other.key + i, Other.key + i + Count, key + j); 216 std::copy(Other.val + i, Other.val + i + Count, val + j); 217 } 218 219 /// moveLeft - Move elements to the left. 220 /// @param i Beginning of the source range. 221 /// @param j Beginning of the destination range. 222 /// @param Count Number of elements to copy. 223 void moveLeft(unsigned i, unsigned j, unsigned Count) { 224 assert(j <= i && "Use moveRight shift elements right"); 225 copy(*this, i, j, Count); 226 } 227 228 /// moveRight - Move elements to the right. 229 /// @param i Beginning of the source range. 230 /// @param j Beginning of the destination range. 231 /// @param Count Number of elements to copy. 232 void moveRight(unsigned i, unsigned j, unsigned Count) { 233 assert(i <= j && "Use moveLeft shift elements left"); 234 assert(j + Count <= N && "Invalid range"); 235 std::copy_backward(key + i, key + i + Count, key + j + Count); 236 std::copy_backward(val + i, val + i + Count, val + j + Count); 237 } 238 239 /// erase - Erase elements [i;j). 240 /// @param i Beginning of the range to erase. 241 /// @param j End of the range. (Exclusive). 242 /// @param Size Number of elements in node. 243 void erase(unsigned i, unsigned j, unsigned Size) { 244 moveLeft(j, i, Size - j); 245 } 246 247 /// shift - Shift elements [i;size) 1 position to the right. 248 /// @param i Beginning of the range to move. 249 /// @param Size Number of elements in node. 250 void shift(unsigned i, unsigned Size) { 251 moveRight(i, i + 1, Size - i); 252 } 253 254 /// transferToLeftSib - Transfer elements to a left sibling node. 255 /// @param Size Number of elements in this. 256 /// @param Sib Left sibling node. 257 /// @param SSize Number of elements in sib. 258 /// @param Count Number of elements to transfer. 259 void transferToLeftSib(unsigned Size, NodeBase &Sib, unsigned SSize, 260 unsigned Count) { 261 Sib.copy(*this, 0, SSize, Count); 262 erase(0, Count, Size); 263 } 264 265 /// transferToRightSib - Transfer elements to a right sibling node. 266 /// @param Size Number of elements in this. 267 /// @param Sib Right sibling node. 268 /// @param SSize Number of elements in sib. 269 /// @param Count Number of elements to transfer. 270 void transferToRightSib(unsigned Size, NodeBase &Sib, unsigned SSize, 271 unsigned Count) { 272 Sib.moveRight(0, Count, SSize); 273 Sib.copy(*this, Size-Count, 0, Count); 274 } 275 276 /// adjustFromLeftSib - Adjust the number if elements in this node by moving 277 /// elements to or from a left sibling node. 278 /// @param Size Number of elements in this. 279 /// @param Sib Right sibling node. 280 /// @param SSize Number of elements in sib. 281 /// @param Add The number of elements to add to this node, possibly < 0. 282 /// @return Number of elements added to this node, possibly negative. 283 int adjustFromLeftSib(unsigned Size, NodeBase &Sib, unsigned SSize, int Add) { 284 if (Add > 0) { 285 // We want to grow, copy from sib. 286 unsigned Count = std::min(std::min(unsigned(Add), SSize), N - Size); 287 Sib.transferToRightSib(SSize, *this, Size, Count); 288 return Count; 289 } else { 290 // We want to shrink, copy to sib. 291 unsigned Count = std::min(std::min(unsigned(-Add), Size), N - SSize); 292 transferToLeftSib(Size, Sib, SSize, Count); 293 return -Count; 294 } 295 } 296}; 297 298 299//===----------------------------------------------------------------------===// 300//--- NodeSizer ---// 301//===----------------------------------------------------------------------===// 302// 303// Compute node sizes from key and value types. 304// 305// The branching factors are chosen to make nodes fit in three cache lines. 306// This may not be possible if keys or values are very large. Such large objects 307// are handled correctly, but a std::map would probably give better performance. 308// 309//===----------------------------------------------------------------------===// 310 311enum { 312 // Cache line size. Most architectures have 32 or 64 byte cache lines. 313 // We use 64 bytes here because it provides good branching factors. 314 Log2CacheLine = 6, 315 CacheLineBytes = 1 << Log2CacheLine, 316 DesiredNodeBytes = 3 * CacheLineBytes 317}; 318 319template <typename KeyT, typename ValT> 320struct NodeSizer { 321 enum { 322 // Compute the leaf node branching factor that makes a node fit in three 323 // cache lines. The branching factor must be at least 3, or some B+-tree 324 // balancing algorithms won't work. 325 // LeafSize can't be larger than CacheLineBytes. This is required by the 326 // PointerIntPair used by NodeRef. 327 DesiredLeafSize = DesiredNodeBytes / 328 static_cast<unsigned>(2*sizeof(KeyT)+sizeof(ValT)), 329 MinLeafSize = 3, 330 LeafSize = DesiredLeafSize > MinLeafSize ? DesiredLeafSize : MinLeafSize 331 }; 332 333 typedef NodeBase<std::pair<KeyT, KeyT>, ValT, LeafSize> LeafBase; 334 335 enum { 336 // Now that we have the leaf branching factor, compute the actual allocation 337 // unit size by rounding up to a whole number of cache lines. 338 AllocBytes = (sizeof(LeafBase) + CacheLineBytes-1) & ~(CacheLineBytes-1), 339 340 // Determine the branching factor for branch nodes. 341 BranchSize = AllocBytes / 342 static_cast<unsigned>(sizeof(KeyT) + sizeof(void*)) 343 }; 344 345 /// Allocator - The recycling allocator used for both branch and leaf nodes. 346 /// This typedef is very likely to be identical for all IntervalMaps with 347 /// reasonably sized entries, so the same allocator can be shared among 348 /// different kinds of maps. 349 typedef RecyclingAllocator<BumpPtrAllocator, char, 350 AllocBytes, CacheLineBytes> Allocator; 351 352}; 353 354 355//===----------------------------------------------------------------------===// 356//--- NodeRef ---// 357//===----------------------------------------------------------------------===// 358// 359// B+-tree nodes can be leaves or branches, so we need a polymorphic node 360// pointer that can point to both kinds. 361// 362// All nodes are cache line aligned and the low 6 bits of a node pointer are 363// always 0. These bits are used to store the number of elements in the 364// referenced node. Besides saving space, placing node sizes in the parents 365// allow tree balancing algorithms to run without faulting cache lines for nodes 366// that may not need to be modified. 367// 368// A NodeRef doesn't know whether it references a leaf node or a branch node. 369// It is the responsibility of the caller to use the correct types. 370// 371// Nodes are never supposed to be empty, and it is invalid to store a node size 372// of 0 in a NodeRef. The valid range of sizes is 1-64. 373// 374//===----------------------------------------------------------------------===// 375 376struct CacheAlignedPointerTraits { 377 static inline void *getAsVoidPointer(void *P) { return P; } 378 static inline void *getFromVoidPointer(void *P) { return P; } 379 enum { NumLowBitsAvailable = Log2CacheLine }; 380}; 381 382template <typename KeyT, typename ValT, typename Traits> 383class NodeRef { 384public: 385 typedef LeafNode<KeyT, ValT, NodeSizer<KeyT, ValT>::LeafSize, Traits> Leaf; 386 typedef BranchNode<KeyT, ValT, NodeSizer<KeyT, ValT>::BranchSize, 387 Traits> Branch; 388 389private: 390 PointerIntPair<void*, Log2CacheLine, unsigned, CacheAlignedPointerTraits> pip; 391 392public: 393 /// NodeRef - Create a null ref. 394 NodeRef() {} 395 396 /// operator bool - Detect a null ref. 397 operator bool() const { return pip.getOpaqueValue(); } 398 399 /// NodeRef - Create a reference to the leaf node p with n elements. 400 NodeRef(Leaf *p, unsigned n) : pip(p, n - 1) {} 401 402 /// NodeRef - Create a reference to the branch node p with n elements. 403 NodeRef(Branch *p, unsigned n) : pip(p, n - 1) {} 404 405 /// size - Return the number of elements in the referenced node. 406 unsigned size() const { return pip.getInt() + 1; } 407 408 /// setSize - Update the node size. 409 void setSize(unsigned n) { pip.setInt(n - 1); } 410 411 /// leaf - Return the referenced leaf node. 412 /// Note there are no dynamic type checks. 413 Leaf &leaf() const { 414 return *reinterpret_cast<Leaf*>(pip.getPointer()); 415 } 416 417 /// branch - Return the referenced branch node. 418 /// Note there are no dynamic type checks. 419 Branch &branch() const { 420 return *reinterpret_cast<Branch*>(pip.getPointer()); 421 } 422 423 bool operator==(const NodeRef &RHS) const { 424 if (pip == RHS.pip) 425 return true; 426 assert(pip.getPointer() != RHS.pip.getPointer() && "Inconsistent NodeRefs"); 427 return false; 428 } 429 430 bool operator!=(const NodeRef &RHS) const { 431 return !operator==(RHS); 432 } 433}; 434 435//===----------------------------------------------------------------------===// 436//--- Leaf nodes ---// 437//===----------------------------------------------------------------------===// 438// 439// Leaf nodes store up to N disjoint intervals with corresponding values. 440// 441// The intervals are kept sorted and fully coalesced so there are no adjacent 442// intervals mapping to the same value. 443// 444// These constraints are always satisfied: 445// 446// - Traits::stopLess(key[i].start, key[i].stop) - Non-empty, sane intervals. 447// 448// - Traits::stopLess(key[i].stop, key[i + 1].start) - Sorted. 449// 450// - val[i] != val[i + 1] || 451// !Traits::adjacent(key[i].stop, key[i + 1].start) - Fully coalesced. 452// 453//===----------------------------------------------------------------------===// 454 455template <typename KeyT, typename ValT, unsigned N, typename Traits> 456class LeafNode : public NodeBase<std::pair<KeyT, KeyT>, ValT, N> { 457public: 458 const KeyT &start(unsigned i) const { return this->key[i].first; } 459 const KeyT &stop(unsigned i) const { return this->key[i].second; } 460 const ValT &value(unsigned i) const { return this->val[i]; } 461 462 KeyT &start(unsigned i) { return this->key[i].first; } 463 KeyT &stop(unsigned i) { return this->key[i].second; } 464 ValT &value(unsigned i) { return this->val[i]; } 465 466 /// findFrom - Find the first interval after i that may contain x. 467 /// @param i Starting index for the search. 468 /// @param Size Number of elements in node. 469 /// @param x Key to search for. 470 /// @return First index with !stopLess(key[i].stop, x), or size. 471 /// This is the first interval that can possibly contain x. 472 unsigned findFrom(unsigned i, unsigned Size, KeyT x) const { 473 assert(i <= Size && Size <= N && "Bad indices"); 474 assert((i == 0 || Traits::stopLess(stop(i - 1), x)) && 475 "Index is past the needed point"); 476 while (i != Size && Traits::stopLess(stop(i), x)) ++i; 477 return i; 478 } 479 480 /// safeFind - Find an interval that is known to exist. This is the same as 481 /// findFrom except is it assumed that x is at least within range of the last 482 /// interval. 483 /// @param i Starting index for the search. 484 /// @param x Key to search for. 485 /// @return First index with !stopLess(key[i].stop, x), never size. 486 /// This is the first interval that can possibly contain x. 487 unsigned safeFind(unsigned i, KeyT x) const { 488 assert(i < N && "Bad index"); 489 assert((i == 0 || Traits::stopLess(stop(i - 1), x)) && 490 "Index is past the needed point"); 491 while (Traits::stopLess(stop(i), x)) ++i; 492 assert(i < N && "Unsafe intervals"); 493 return i; 494 } 495 496 /// safeLookup - Lookup mapped value for a safe key. 497 /// It is assumed that x is within range of the last entry. 498 /// @param x Key to search for. 499 /// @param NotFound Value to return if x is not in any interval. 500 /// @return The mapped value at x or NotFound. 501 ValT safeLookup(KeyT x, ValT NotFound) const { 502 unsigned i = safeFind(0, x); 503 return Traits::startLess(x, start(i)) ? NotFound : value(i); 504 } 505 506 IdxPair insertFrom(unsigned i, unsigned Size, KeyT a, KeyT b, ValT y); 507 unsigned extendStop(unsigned i, unsigned Size, KeyT b); 508 509#ifndef NDEBUG 510 void dump(unsigned Size) { 511 errs() << " N" << this << " [shape=record label=\"{ " << Size << '/' << N; 512 for (unsigned i = 0; i != Size; ++i) 513 errs() << " | {" << start(i) << '-' << stop(i) << "|" << value(i) << '}'; 514 errs() << "}\"];\n"; 515 } 516#endif 517 518}; 519 520/// insertFrom - Add mapping of [a;b] to y if possible, coalescing as much as 521/// possible. This may cause the node to grow by 1, or it may cause the node 522/// to shrink because of coalescing. 523/// @param i Starting index = insertFrom(0, size, a) 524/// @param Size Number of elements in node. 525/// @param a Interval start. 526/// @param b Interval stop. 527/// @param y Value be mapped. 528/// @return (insert position, new size), or (i, Capacity+1) on overflow. 529template <typename KeyT, typename ValT, unsigned N, typename Traits> 530IdxPair LeafNode<KeyT, ValT, N, Traits>:: 531insertFrom(unsigned i, unsigned Size, KeyT a, KeyT b, ValT y) { 532 assert(i <= Size && Size <= N && "Invalid index"); 533 assert(!Traits::stopLess(b, a) && "Invalid interval"); 534 535 // Verify the findFrom invariant. 536 assert((i == 0 || Traits::stopLess(stop(i - 1), a))); 537 assert((i == Size || !Traits::stopLess(stop(i), a))); 538 539 // Coalesce with previous interval. 540 if (i && value(i - 1) == y && Traits::adjacent(stop(i - 1), a)) 541 return IdxPair(i - 1, extendStop(i - 1, Size, b)); 542 543 // Detect overflow. 544 if (i == N) 545 return IdxPair(i, N + 1); 546 547 // Add new interval at end. 548 if (i == Size) { 549 start(i) = a; 550 stop(i) = b; 551 value(i) = y; 552 return IdxPair(i, Size + 1); 553 } 554 555 // Overlapping intervals? 556 if (!Traits::stopLess(b, start(i))) { 557 assert(value(i) == y && "Inconsistent values in overlapping intervals"); 558 if (Traits::startLess(a, start(i))) 559 start(i) = a; 560 return IdxPair(i, extendStop(i, Size, b)); 561 } 562 563 // Try to coalesce with following interval. 564 if (value(i) == y && Traits::adjacent(b, start(i))) { 565 start(i) = a; 566 return IdxPair(i, Size); 567 } 568 569 // We must insert before i. Detect overflow. 570 if (Size == N) 571 return IdxPair(i, N + 1); 572 573 // Insert before i. 574 this->shift(i, Size); 575 start(i) = a; 576 stop(i) = b; 577 value(i) = y; 578 return IdxPair(i, Size + 1); 579} 580 581/// extendStop - Extend stop(i) to b, coalescing with following intervals. 582/// @param i Interval to extend. 583/// @param Size Number of elements in node. 584/// @param b New interval end point. 585/// @return New node size after coalescing. 586template <typename KeyT, typename ValT, unsigned N, typename Traits> 587unsigned LeafNode<KeyT, ValT, N, Traits>:: 588extendStop(unsigned i, unsigned Size, KeyT b) { 589 assert(i < Size && Size <= N && "Bad indices"); 590 591 // Are we even extending the interval? 592 if (Traits::startLess(b, stop(i))) 593 return Size; 594 595 // Find the first interval that may be preserved. 596 unsigned j = findFrom(i + 1, Size, b); 597 if (j < Size) { 598 // Would key[i] overlap key[j] after the extension? 599 if (Traits::stopLess(b, start(j))) { 600 // Not overlapping. Perhaps adjacent and coalescable? 601 if (value(i) == value(j) && Traits::adjacent(b, start(j))) 602 b = stop(j++); 603 } else { 604 // Overlap. Include key[j] in the new interval. 605 assert(value(i) == value(j) && "Overlapping values"); 606 b = stop(j++); 607 } 608 } 609 stop(i) = b; 610 611 // Entries [i+1;j) were coalesced. 612 if (i + 1 < j && j < Size) 613 this->erase(i + 1, j, Size); 614 return Size - (j - (i + 1)); 615} 616 617 618//===----------------------------------------------------------------------===// 619//--- Branch nodes ---// 620//===----------------------------------------------------------------------===// 621// 622// A branch node stores references to 1--N subtrees all of the same height. 623// 624// The key array in a branch node holds the rightmost stop key of each subtree. 625// It is redundant to store the last stop key since it can be found in the 626// parent node, but doing so makes tree balancing a lot simpler. 627// 628// It is unusual for a branch node to only have one subtree, but it can happen 629// in the root node if it is smaller than the normal nodes. 630// 631// When all of the leaf nodes from all the subtrees are concatenated, they must 632// satisfy the same constraints as a single leaf node. They must be sorted, 633// sane, and fully coalesced. 634// 635//===----------------------------------------------------------------------===// 636 637template <typename KeyT, typename ValT, unsigned N, typename Traits> 638class BranchNode : public NodeBase<KeyT, NodeRef<KeyT, ValT, Traits>, N> { 639 typedef NodeRef<KeyT, ValT, Traits> NodeRefT; 640public: 641 const KeyT &stop(unsigned i) const { return this->key[i]; } 642 const NodeRefT &subtree(unsigned i) const { return this->val[i]; } 643 644 KeyT &stop(unsigned i) { return this->key[i]; } 645 NodeRefT &subtree(unsigned i) { return this->val[i]; } 646 647 /// findFrom - Find the first subtree after i that may contain x. 648 /// @param i Starting index for the search. 649 /// @param Size Number of elements in node. 650 /// @param x Key to search for. 651 /// @return First index with !stopLess(key[i], x), or size. 652 /// This is the first subtree that can possibly contain x. 653 unsigned findFrom(unsigned i, unsigned Size, KeyT x) const { 654 assert(i <= Size && Size <= N && "Bad indices"); 655 assert((i == 0 || Traits::stopLess(stop(i - 1), x)) && 656 "Index to findFrom is past the needed point"); 657 while (i != Size && Traits::stopLess(stop(i), x)) ++i; 658 return i; 659 } 660 661 /// safeFind - Find a subtree that is known to exist. This is the same as 662 /// findFrom except is it assumed that x is in range. 663 /// @param i Starting index for the search. 664 /// @param x Key to search for. 665 /// @return First index with !stopLess(key[i], x), never size. 666 /// This is the first subtree that can possibly contain x. 667 unsigned safeFind(unsigned i, KeyT x) const { 668 assert(i < N && "Bad index"); 669 assert((i == 0 || Traits::stopLess(stop(i - 1), x)) && 670 "Index is past the needed point"); 671 while (Traits::stopLess(stop(i), x)) ++i; 672 assert(i < N && "Unsafe intervals"); 673 return i; 674 } 675 676 /// safeLookup - Get the subtree containing x, Assuming that x is in range. 677 /// @param x Key to search for. 678 /// @return Subtree containing x 679 NodeRefT safeLookup(KeyT x) const { 680 return subtree(safeFind(0, x)); 681 } 682 683 /// insert - Insert a new (subtree, stop) pair. 684 /// @param i Insert position, following entries will be shifted. 685 /// @param Size Number of elements in node. 686 /// @param Node Subtree to insert. 687 /// @param Stop Last key in subtree. 688 void insert(unsigned i, unsigned Size, NodeRefT Node, KeyT Stop) { 689 assert(Size < N && "branch node overflow"); 690 assert(i <= Size && "Bad insert position"); 691 this->shift(i, Size); 692 subtree(i) = Node; 693 stop(i) = Stop; 694 } 695 696#ifndef NDEBUG 697 void dump(unsigned Size) { 698 errs() << " N" << this << " [shape=record label=\"" << Size << '/' << N; 699 for (unsigned i = 0; i != Size; ++i) 700 errs() << " | <s" << i << "> " << stop(i); 701 errs() << "\"];\n"; 702 for (unsigned i = 0; i != Size; ++i) 703 errs() << " N" << this << ":s" << i << " -> N" 704 << &subtree(i).branch() << ";\n"; 705 } 706#endif 707 708}; 709 710} // namespace IntervalMapImpl 711 712 713//===----------------------------------------------------------------------===// 714//--- IntervalMap ----// 715//===----------------------------------------------------------------------===// 716 717template <typename KeyT, typename ValT, 718 unsigned N = IntervalMapImpl::NodeSizer<KeyT, ValT>::LeafSize, 719 typename Traits = IntervalMapInfo<KeyT> > 720class IntervalMap { 721 typedef IntervalMapImpl::NodeRef<KeyT, ValT, Traits> NodeRef; 722 typedef IntervalMapImpl::NodeSizer<KeyT, ValT> NodeSizer; 723 typedef typename NodeRef::Leaf Leaf; 724 typedef typename NodeRef::Branch Branch; 725 typedef IntervalMapImpl::LeafNode<KeyT, ValT, N, Traits> RootLeaf; 726 typedef IntervalMapImpl::IdxPair IdxPair; 727 728 // The RootLeaf capacity is given as a template parameter. We must compute the 729 // corresponding RootBranch capacity. 730 enum { 731 DesiredRootBranchCap = (sizeof(RootLeaf) - sizeof(KeyT)) / 732 (sizeof(KeyT) + sizeof(NodeRef)), 733 RootBranchCap = DesiredRootBranchCap ? DesiredRootBranchCap : 1 734 }; 735 736 typedef IntervalMapImpl::BranchNode<KeyT, ValT, RootBranchCap, Traits> RootBranch; 737 738 // When branched, we store a global start key as well as the branch node. 739 struct RootBranchData { 740 KeyT start; 741 RootBranch node; 742 }; 743 744 enum { 745 RootDataSize = sizeof(RootBranchData) > sizeof(RootLeaf) ? 746 sizeof(RootBranchData) : sizeof(RootLeaf) 747 }; 748 749public: 750 typedef typename NodeSizer::Allocator Allocator; 751 752private: 753 // The root data is either a RootLeaf or a RootBranchData instance. 754 // We can't put them in a union since C++03 doesn't allow non-trivial 755 // constructors in unions. 756 // Instead, we use a char array with pointer alignment. The alignment is 757 // ensured by the allocator member in the class, but still verified in the 758 // constructor. We don't support keys or values that are more aligned than a 759 // pointer. 760 char data[RootDataSize]; 761 762 // Tree height. 763 // 0: Leaves in root. 764 // 1: Root points to leaf. 765 // 2: root->branch->leaf ... 766 unsigned height; 767 768 // Number of entries in the root node. 769 unsigned rootSize; 770 771 // Allocator used for creating external nodes. 772 Allocator &allocator; 773 774 /// dataAs - Represent data as a node type without breaking aliasing rules. 775 template <typename T> 776 T &dataAs() const { 777 union { 778 const char *d; 779 T *t; 780 } u; 781 u.d = data; 782 return *u.t; 783 } 784 785 const RootLeaf &rootLeaf() const { 786 assert(!branched() && "Cannot acces leaf data in branched root"); 787 return dataAs<RootLeaf>(); 788 } 789 RootLeaf &rootLeaf() { 790 assert(!branched() && "Cannot acces leaf data in branched root"); 791 return dataAs<RootLeaf>(); 792 } 793 RootBranchData &rootBranchData() const { 794 assert(branched() && "Cannot access branch data in non-branched root"); 795 return dataAs<RootBranchData>(); 796 } 797 RootBranchData &rootBranchData() { 798 assert(branched() && "Cannot access branch data in non-branched root"); 799 return dataAs<RootBranchData>(); 800 } 801 const RootBranch &rootBranch() const { return rootBranchData().node; } 802 RootBranch &rootBranch() { return rootBranchData().node; } 803 KeyT rootBranchStart() const { return rootBranchData().start; } 804 KeyT &rootBranchStart() { return rootBranchData().start; } 805 806 Leaf *allocLeaf() { 807 return new(allocator.template Allocate<Leaf>()) Leaf(); 808 } 809 void deleteLeaf(Leaf *P) { 810 P->~Leaf(); 811 allocator.Deallocate(P); 812 } 813 814 Branch *allocBranch() { 815 return new(allocator.template Allocate<Branch>()) Branch(); 816 } 817 void deleteBranch(Branch *P) { 818 P->~Branch(); 819 allocator.Deallocate(P); 820 } 821 822 823 IdxPair branchRoot(unsigned Position); 824 IdxPair splitRoot(unsigned Position); 825 826 void switchRootToBranch() { 827 rootLeaf().~RootLeaf(); 828 height = 1; 829 new (&rootBranchData()) RootBranchData(); 830 } 831 832 void switchRootToLeaf() { 833 rootBranchData().~RootBranchData(); 834 height = 0; 835 new(&rootLeaf()) RootLeaf(); 836 } 837 838 bool branched() const { return height > 0; } 839 840 ValT treeSafeLookup(KeyT x, ValT NotFound) const; 841 void visitNodes(void (IntervalMap::*f)(NodeRef, unsigned Level)); 842 void deleteNode(NodeRef Node, unsigned Level); 843 844public: 845 explicit IntervalMap(Allocator &a) : height(0), rootSize(0), allocator(a) { 846 assert((uintptr_t(data) & (alignOf<RootLeaf>() - 1)) == 0 && 847 "Insufficient alignment"); 848 new(&rootLeaf()) RootLeaf(); 849 } 850 851 /// empty - Return true when no intervals are mapped. 852 bool empty() const { 853 return rootSize == 0; 854 } 855 856 /// start - Return the smallest mapped key in a non-empty map. 857 KeyT start() const { 858 assert(!empty() && "Empty IntervalMap has no start"); 859 return !branched() ? rootLeaf().start(0) : rootBranchStart(); 860 } 861 862 /// stop - Return the largest mapped key in a non-empty map. 863 KeyT stop() const { 864 assert(!empty() && "Empty IntervalMap has no stop"); 865 return !branched() ? rootLeaf().stop(rootSize - 1) : 866 rootBranch().stop(rootSize - 1); 867 } 868 869 /// lookup - Return the mapped value at x or NotFound. 870 ValT lookup(KeyT x, ValT NotFound = ValT()) const { 871 if (empty() || Traits::startLess(x, start()) || Traits::stopLess(stop(), x)) 872 return NotFound; 873 return branched() ? treeSafeLookup(x, NotFound) : 874 rootLeaf().safeLookup(x, NotFound); 875 } 876 877 /// insert - Add a mapping of [a;b] to y, coalesce with adjacent intervals. 878 /// It is assumed that no key in the interval is mapped to another value, but 879 /// overlapping intervals already mapped to y will be coalesced. 880 void insert(KeyT a, KeyT b, ValT y) { 881 find(a).insert(a, b, y); 882 } 883 884 /// clear - Remove all entries. 885 void clear(); 886 887 class const_iterator; 888 class iterator; 889 friend class const_iterator; 890 friend class iterator; 891 892 const_iterator begin() const { 893 iterator I(*this); 894 I.goToBegin(); 895 return I; 896 } 897 898 iterator begin() { 899 iterator I(*this); 900 I.goToBegin(); 901 return I; 902 } 903 904 const_iterator end() const { 905 iterator I(*this); 906 I.goToEnd(); 907 return I; 908 } 909 910 iterator end() { 911 iterator I(*this); 912 I.goToEnd(); 913 return I; 914 } 915 916 /// find - Return an iterator pointing to the first interval ending at or 917 /// after x, or end(). 918 const_iterator find(KeyT x) const { 919 iterator I(*this); 920 I.find(x); 921 return I; 922 } 923 924 iterator find(KeyT x) { 925 iterator I(*this); 926 I.find(x); 927 return I; 928 } 929 930#ifndef NDEBUG 931 void dump(); 932 void dumpNode(NodeRef Node, unsigned Height); 933#endif 934}; 935 936/// treeSafeLookup - Return the mapped value at x or NotFound, assuming a 937/// branched root. 938template <typename KeyT, typename ValT, unsigned N, typename Traits> 939ValT IntervalMap<KeyT, ValT, N, Traits>:: 940treeSafeLookup(KeyT x, ValT NotFound) const { 941 assert(branched() && "treeLookup assumes a branched root"); 942 943 NodeRef NR = rootBranch().safeLookup(x); 944 for (unsigned h = height-1; h; --h) 945 NR = NR.branch().safeLookup(x); 946 return NR.leaf().safeLookup(x, NotFound); 947} 948 949 950// branchRoot - Switch from a leaf root to a branched root. 951// Return the new (root offset, node offset) corresponding to Position. 952template <typename KeyT, typename ValT, unsigned N, typename Traits> 953IntervalMapImpl::IdxPair IntervalMap<KeyT, ValT, N, Traits>:: 954branchRoot(unsigned Position) { 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].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].leaf().stop(size[n]-1); 982 rootBranch().subtree(n) = node[n]; 983 } 984 rootBranchStart() = node[0].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 // How many external leaf nodes to hold RootBranch+1? 995 const unsigned Nodes = RootBranch::Capacity / Branch::Capacity + 1; 996 997 // Compute element distribution among new nodes. 998 unsigned Size[Nodes]; 999 IdxPair NewOffset(0, Position); 1000 1001 // Is is very common for the root node to be smaller than external nodes. 1002 if (Nodes == 1) 1003 Size[0] = rootSize; 1004 else 1005 NewOffset = distribute(Nodes, rootSize, Leaf::Capacity, NULL, Size, 1006 Position, true); 1007 1008 // Allocate new nodes. 1009 unsigned Pos = 0; 1010 NodeRef Node[Nodes]; 1011 for (unsigned n = 0; n != Nodes; ++n) { 1012 Node[n] = NodeRef(allocBranch(), Size[n]); 1013 Node[n].branch().copy(rootBranch(), Pos, 0, Size[n]); 1014 Pos += Size[n]; 1015 } 1016 1017 for (unsigned n = 0; n != Nodes; ++n) { 1018 rootBranch().stop(n) = Node[n].branch().stop(Size[n]-1); 1019 rootBranch().subtree(n) = Node[n]; 1020 } 1021 rootSize = Nodes; 1022 return NewOffset; 1023} 1024 1025/// visitNodes - Visit each external node. 1026template <typename KeyT, typename ValT, unsigned N, typename Traits> 1027void IntervalMap<KeyT, ValT, N, Traits>:: 1028visitNodes(void (IntervalMap::*f)(NodeRef, unsigned Height)) { 1029 if (!branched()) 1030 return; 1031 SmallVector<NodeRef, 4> Refs, NextRefs; 1032 1033 // Collect level 0 nodes from the root. 1034 for (unsigned i = 0; i != rootSize; ++i) 1035 Refs.push_back(rootBranch().subtree(i)); 1036 1037 // Visit all branch nodes. 1038 for (unsigned h = height - 1; h; --h) { 1039 for (unsigned i = 0, e = Refs.size(); i != e; ++i) { 1040 Branch &B = Refs[i].branch(); 1041 for (unsigned j = 0, s = Refs[i].size(); j != s; ++j) 1042 NextRefs.push_back(B.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(NodeRef Node, unsigned Level) { 1057 if (Level) 1058 deleteBranch(&Node.branch()); 1059 else 1060 deleteLeaf(&Node.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(NodeRef Node, unsigned Height) { 1077 if (Height) 1078 Node.branch().dump(Node.size()); 1079 else 1080 Node.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<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.branch().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 NodeRef pathNode(unsigned h) const { return path[h].first; } 1138 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.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 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.branch().subtree(path.back().second); 1167 } 1168 1169 void pathFillLeft(); 1170 void pathFillFind(KeyT x); 1171 void pathFillRight(); 1172 1173 NodeRef leftSibling(unsigned level) const; 1174 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 NodeRef NR = pathNextDown(); 1300 for (unsigned i = map->height - path.size() - 1; i; --i) { 1301 path.push_back(PathEntry(NR, 0)); 1302 NR = NR.branch().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 NodeRef NR = pathNextDown(); 1312 for (unsigned i = map->height - path.size() - 1; i; --i) { 1313 unsigned p = NR.branch().safeFind(0, x); 1314 path.push_back(PathEntry(NR, p)); 1315 NR = NR.branch().subtree(p); 1316 } 1317 path.push_back(PathEntry(NR, NR.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 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.branch().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> 1337typename IntervalMap<KeyT, ValT, N, Traits>::NodeRef 1338IntervalMap<KeyT, ValT, N, Traits>:: 1339const_iterator::leftSibling(unsigned level) const { 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).branch().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.branch().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> 1367typename IntervalMap<KeyT, ValT, N, Traits>::NodeRef 1368IntervalMap<KeyT, ValT, N, Traits>:: 1369const_iterator::rightSibling(unsigned level) const { 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).branch().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.branch().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, 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).branch() 1512 .subtree(this->pathOffset(Level-1)).setSize(Size); 1513 else 1514 this->map->rootBranch().subtree(this->rootOffset).setSize(Size); 1515} 1516 1517/// setNodeStop - Update the stop key of the current node at level and above. 1518template <typename KeyT, typename ValT, unsigned N, typename Traits> 1519void IntervalMap<KeyT, ValT, N, Traits>:: 1520iterator::setNodeStop(unsigned Level, KeyT Stop) { 1521 while (Level--) { 1522 this->pathNode(Level).branch().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, 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 NodeRef NR = this->pathNode(Level-1); 1559 unsigned Offset = this->pathOffset(Level-1); 1560 assert(NR.size() < Branch::Capacity && "Branch overflow"); 1561 NR.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 unsigned CurSize[4]; 1624 Leaf *Node[4]; 1625 unsigned Nodes = 0; 1626 unsigned Elements = 0; 1627 unsigned Offset = this->treeLeafOffset(); 1628 1629 // Do we have a left sibling? 1630 NodeRef LeftSib = this->leftSibling(this->map->height-1); 1631 if (LeftSib) { 1632 Offset += Elements = CurSize[Nodes] = LeftSib.size(); 1633 Node[Nodes++] = &LeftSib.leaf(); 1634 } 1635 1636 // Current leaf node. 1637 Elements += CurSize[Nodes] = this->treeLeafSize(); 1638 Node[Nodes++] = &this->treeLeaf(); 1639 1640 // Do we have a right sibling? 1641 NodeRef RightSib = this->rightSibling(this->map->height-1); 1642 if (RightSib) { 1643 Offset += Elements = CurSize[Nodes] = RightSib.size(); 1644 Node[Nodes++] = &RightSib.leaf(); 1645 } 1646 1647 // Do we need to allocate a new node? 1648 unsigned NewNode = 0; 1649 if (Elements + 1 > Nodes * Leaf::Capacity) { 1650 // Insert NewNode at the penultimate position, or after a single node. 1651 NewNode = Nodes == 1 ? 1 : Nodes - 1; 1652 CurSize[Nodes] = CurSize[NewNode]; 1653 Node[Nodes] = Node[NewNode]; 1654 CurSize[NewNode] = 0; 1655 Node[NewNode] = this->map->allocLeaf(); 1656 ++Nodes; 1657 } 1658 1659 // Compute the new element distribution. 1660 unsigned NewSize[4]; 1661 IdxPair NewOffset = 1662 IntervalMapImpl::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