src/hotspot/share/libadt/set.hpp
changeset 58962 2dcfc28a314d
parent 58961 5d462d4b7a8b
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     1 /*
       
     2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
       
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       
     4  *
       
     5  * This code is free software; you can redistribute it and/or modify it
       
     6  * under the terms of the GNU General Public License version 2 only, as
       
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    13  * accompanied this code).
       
    14  *
       
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    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
       
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    23  */
       
    24 
       
    25 #ifndef SHARE_LIBADT_SET_HPP
       
    26 #define SHARE_LIBADT_SET_HPP
       
    27 
       
    28 #include "memory/allocation.hpp"
       
    29 
       
    30 // Sets - An Abstract Data Type
       
    31 
       
    32 class SparseSet;
       
    33 class VectorSet;
       
    34 class ListSet;
       
    35 class CoSet;
       
    36 
       
    37 class ostream;
       
    38 class SetI_;
       
    39 
       
    40 // These sets can grow or shrink, based on the initial size and the largest
       
    41 // element currently in them.  Basically, they allow a bunch of bits to be
       
    42 // grouped together, tested, set & cleared, intersected, etc.  The basic
       
    43 // Set class is an abstract class, and cannot be constructed.  Instead,
       
    44 // one of VectorSet, SparseSet, or ListSet is created.  Each variation has
       
    45 // different asymptotic running times for different operations, and different
       
    46 // constants of proportionality as well.
       
    47 // {n = number of elements, N = largest element}
       
    48 
       
    49 //              VectorSet       SparseSet       ListSet
       
    50 // Create       O(N)            O(1)            O(1)
       
    51 // Clear        O(N)            O(1)            O(1)
       
    52 // Insert       O(1)            O(1)            O(log n)
       
    53 // Delete       O(1)            O(1)            O(log n)
       
    54 // Member       O(1)            O(1)            O(log n)
       
    55 // Size         O(N)            O(1)            O(1)
       
    56 // Copy         O(N)            O(n)            O(n)
       
    57 // Union        O(N)            O(n)            O(n log n)
       
    58 // Intersect    O(N)            O(n)            O(n log n)
       
    59 // Difference   O(N)            O(n)            O(n log n)
       
    60 // Equal        O(N)            O(n)            O(n log n)
       
    61 // ChooseMember O(N)            O(1)            O(1)
       
    62 // Sort         O(1)            O(n log n)      O(1)
       
    63 // Forall       O(N)            O(n)            O(n)
       
    64 // Complement   O(1)            O(1)            O(1)
       
    65 
       
    66 // TIME:        N/32            n               8*n     Accesses
       
    67 // SPACE:       N/8             4*N+4*n         8*n     Bytes
       
    68 
       
    69 // Create:      Make an empty set
       
    70 // Clear:       Remove all the elements of a Set
       
    71 // Insert:      Insert an element into a Set; duplicates are ignored
       
    72 // Delete:      Removes an element from a Set
       
    73 // Member:      Tests for membership in a Set
       
    74 // Size:        Returns the number of members of a Set
       
    75 // Copy:        Copy or assign one Set to another
       
    76 // Union:       Union 2 sets together
       
    77 // Intersect:   Intersect 2 sets together
       
    78 // Difference:  Compute A & !B; remove from set A those elements in set B
       
    79 // Equal:       Test for equality between 2 sets
       
    80 // ChooseMember Pick a random member
       
    81 // Sort:        If no other operation changes the set membership, a following
       
    82 //              Forall will iterate the members in ascending order.
       
    83 // Forall:      Iterate over the elements of a Set.  Operations that modify
       
    84 //              the set membership during iteration work, but the iterator may
       
    85 //              skip any member or duplicate any member.
       
    86 // Complement:  Only supported in the Co-Set variations.  It adds a small
       
    87 //              constant-time test to every Set operation.
       
    88 //
       
    89 // PERFORMANCE ISSUES:
       
    90 // If you "cast away" the specific set variation you are using, and then do
       
    91 // operations on the basic "Set" object you will pay a virtual function call
       
    92 // to get back the specific set variation.  On the other hand, using the
       
    93 // generic Set means you can change underlying implementations by just
       
    94 // changing the initial declaration.  Examples:
       
    95 //      void foo(VectorSet vs1, VectorSet vs2) { vs1 |= vs2; }
       
    96 // "foo" must be called with a VectorSet.  The vector set union operation
       
    97 // is called directly.
       
    98 //      void foo(Set vs1, Set vs2) { vs1 |= vs2; }
       
    99 // "foo" may be called with *any* kind of sets; suppose it is called with
       
   100 // VectorSets.  Two virtual function calls are used to figure out the that vs1
       
   101 // and vs2 are VectorSets.  In addition, if vs2 is not a VectorSet then a
       
   102 // temporary VectorSet copy of vs2 will be made before the union proceeds.
       
   103 //
       
   104 // VectorSets have a small constant.  Time and space are proportional to the
       
   105 //   largest element.  Fine for dense sets and largest element < 10,000.
       
   106 // SparseSets have a medium constant.  Time is proportional to the number of
       
   107 //   elements, space is proportional to the largest element.
       
   108 //   Fine (but big) with the largest element < 100,000.
       
   109 // ListSets have a big constant.  Time *and space* are proportional to the
       
   110 //   number of elements.  They work well for a few elements of *any* size
       
   111 //   (i.e. sets of pointers)!
       
   112 
       
   113 //------------------------------Set--------------------------------------------
       
   114 class Set : public ResourceObj {
       
   115  protected:
       
   116 
       
   117   // Creates a new, empty set.
       
   118   Set(Arena *arena) : _set_arena(arena) {};
       
   119 
       
   120   // Creates a new set from an existing set
       
   121   Set(const Set & s) : ResourceObj(s) {};
       
   122 
       
   123  public:
       
   124   // Set assignment; deep-copy guts
       
   125   virtual Set &operator =(const Set &s)=0;
       
   126   virtual Set &clone(void) const=0;
       
   127 
       
   128   // Virtual destructor
       
   129   virtual ~Set() {};
       
   130 
       
   131   // Add member to set
       
   132   virtual Set &operator <<=(uint elem)=0;
       
   133   // virtual Set  operator << (uint elem);
       
   134 
       
   135   // Delete member from set
       
   136   virtual Set &operator >>=(uint elem)=0;
       
   137   // virtual Set  operator >> (uint elem);
       
   138 
       
   139   // Membership test.  Result is Zero (absent)/ Non-Zero (present)
       
   140   virtual int operator [](uint elem) const=0;
       
   141 
       
   142   // Intersect sets
       
   143   virtual Set &operator &=(const Set &s)=0;
       
   144   // virtual Set  operator & (const Set &s) const;
       
   145 
       
   146   // Union sets
       
   147   virtual Set &operator |=(const Set &s)=0;
       
   148   // virtual Set  operator | (const Set &s) const;
       
   149 
       
   150   // Difference sets
       
   151   virtual Set &operator -=(const Set &s)=0;
       
   152   // virtual Set  operator - (const Set &s) const;
       
   153 
       
   154   // Tests for equality.  Result is Zero (false)/ Non-Zero (true)
       
   155   virtual int operator ==(const Set &s) const=0;
       
   156   int operator !=(const Set &s) const { return !(*this == s); }
       
   157   virtual int disjoint(const Set &s) const=0;
       
   158 
       
   159   // Tests for strict subset.  Result is Zero (false)/ Non-Zero (true)
       
   160   virtual int operator < (const Set &s) const=0;
       
   161   int operator > (const Set &s) const { return s < *this; }
       
   162 
       
   163   // Tests for subset.  Result is Zero (false)/ Non-Zero (true)
       
   164   virtual int operator <=(const Set &s) const=0;
       
   165   int operator >=(const Set &s) const { return s <= *this; }
       
   166 
       
   167   // Clear all the elements in the Set
       
   168   virtual void Clear(void)=0;
       
   169 
       
   170   // Return the number of members in the Set
       
   171   virtual uint Size(void) const=0;
       
   172 
       
   173   // If an iterator follows a "Sort()" without any Set-modifying operations
       
   174   // inbetween then the iterator will visit the elements in ascending order.
       
   175   virtual void Sort(void)=0;
       
   176 
       
   177   // Convert a set to printable string in an allocated buffer.
       
   178   // The caller must deallocate the string.
       
   179   virtual char *setstr(void) const;
       
   180 
       
   181   // Print the Set on "stdout".  Can be conveniently called in the debugger
       
   182   void print() const;
       
   183 
       
   184   // Parse text from the string into the Set.  Return length parsed.
       
   185   virtual int parse(const char *s);
       
   186 
       
   187   // Convert a generic Set to a specific Set
       
   188   virtual const VectorSet *asVectorSet(void) const;
       
   189 
       
   190   // Hash the set.  Sets of different types but identical elements will NOT
       
   191   // hash the same.  Same set type, same elements WILL hash the same.
       
   192   virtual int hash() const = 0;
       
   193 
       
   194 protected:
       
   195   friend class SetI;
       
   196   virtual class SetI_ *iterate(uint&) const=0;
       
   197 
       
   198   // Need storeage for the set
       
   199   Arena *_set_arena;
       
   200 };
       
   201 
       
   202 //------------------------------Iteration--------------------------------------
       
   203 // Loop thru all elements of the set, setting "elem" to the element numbers
       
   204 // in random order.  Inserted or deleted elements during this operation may
       
   205 // or may not be iterated over; untouched elements will be affected once.
       
   206 
       
   207 // Usage:  for( SetI  i(s); i.test(); i++ ) { body = i.elem; }   ...OR...
       
   208 //         for( i.reset(s); i.test(); i++ ) { body = i.elem; }
       
   209 
       
   210 class SetI_ : public ResourceObj {
       
   211 protected:
       
   212   friend class SetI;
       
   213   virtual ~SetI_();
       
   214   virtual uint next(void)=0;
       
   215   virtual int test(void)=0;
       
   216 };
       
   217 
       
   218 class SetI {
       
   219 protected:
       
   220   SetI_ *impl;
       
   221 public:
       
   222   uint elem;                    // The publically accessible element
       
   223 
       
   224   SetI( const Set *s ) { impl = s->iterate(elem); }
       
   225   ~SetI() { delete impl; }
       
   226   void reset( const Set *s ) { delete impl; impl = s->iterate(elem); }
       
   227   void operator ++(void) { elem = impl->next(); }
       
   228   int test(void) { return impl->test(); }
       
   229 };
       
   230 
       
   231 #endif // SHARE_LIBADT_SET_HPP