1 /*
   2  * Copyright (c) 1997, 2010, 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
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_LIBADT_DICT_HPP
  26 #define SHARE_VM_LIBADT_DICT_HPP
  27 
  28 // Dictionaries - An Abstract Data Type
  29 
  30 #include "memory/allocation.inline.hpp"
  31 #include "memory/resourceArea.hpp"
  32 #include "runtime/thread.hpp"
  33 
  34 class Dict;
  35 
  36 // These dictionaries define a key-value mapping.  They can be inserted to,
  37 // searched or deleted from.  They grow and shrink as needed.  The key is a
  38 // pointer to something (or anything which can be stored in a pointer).  A
  39 // key comparison routine determines if two keys are equal or not.  A hash
  40 // function can be provided; if it's not provided the key itself is used
  41 // instead.  A nice string hash function is included.
  42 typedef int32_t (*CmpKey)(const void *key1, const void *key2);
  43 typedef int  (*Hash)(const void *key);
  44 typedef void (*FuncDict)(const void *key, const void *val, Dict *d);
  45 
  46 class Dict : public ResourceObj { // Dictionary structure
  47  private:
  48   class Arena *_arena;          // Where to draw storage from
  49   class bucket *_bin;           // Hash table is array of buckets
  50   uint _size;                   // Size (# of slots) in hash table
  51   uint32_t _cnt;                // Number of key-value pairs in hash table
  52   const Hash _hash;             // Hashing function
  53   const CmpKey _cmp;            // Key comparison function
  54   void doubhash( void );        // Double hash table size
  55 
  56  public:
  57   friend class DictI;            // Friendly iterator function
  58 
  59   // cmp is a key comparision routine.  hash is a routine to hash a key.
  60   Dict( CmpKey cmp, Hash hash );
  61   Dict( CmpKey cmp, Hash hash, Arena *arena, int size=16 );
  62   ~Dict();
  63 
  64   Dict( const Dict & );         // Deep-copy guts
  65   Dict &operator =( const Dict & );
  66 
  67   // Zap to empty; ready for re-use
  68   void Clear();
  69 
  70   // Return # of key-value pairs in dict
  71   uint32_t Size(void) const { return _cnt; }
  72 
  73   // Insert inserts the given key-value pair into the dictionary.  The prior
  74   // value of the key is returned; NULL if the key was not previously defined.
  75   void *Insert(void *key, void *val, bool replace = true); // A new key-value
  76   void *Delete(void *key);        // Delete & return old
  77 
  78   // Find finds the value of a given key; or NULL if not found.
  79   // The dictionary is NOT changed.
  80   void *operator [](const void *key) const;  // Do a lookup
  81 
  82   // == compares two dictionaries; they must have the same keys (their keys
  83   // must match using CmpKey) and they must have the same values (pointer
  84   // comparison).  If so 1 is returned, if not 0 is returned.
  85   int32_t operator ==(const Dict &d) const;   // Compare dictionaries for equal
  86 
  87   // Print out the dictionary contents as key-value pairs
  88   void print();
  89 };
  90 
  91 // Hashing functions
  92 int hashstr(const void *s);        // Nice string hash
  93 // Slimey cheap hash function; no guaranteed performance.  Better than the
  94 // default for pointers, especially on MS-DOS machines.
  95 int hashptr(const void *key);
  96 // Slimey cheap hash function; no guaranteed performance.
  97 int hashkey(const void *key);
  98 
  99 // Key comparators
 100 int32_t cmpstr(const void *k1, const void *k2);
 101 // Slimey cheap key comparator.
 102 int32_t cmpkey(const void *key1, const void *key2);
 103 
 104 //------------------------------Iteration--------------------------------------
 105 // The class of dictionary iterators.  Fails in the presences of modifications
 106 // to the dictionary during iteration (including searches).
 107 // Usage:  for( DictI i(dict); i.test(); ++i ) { body = i.key; body = i.value;}
 108 class DictI {
 109  private:
 110   const Dict *_d;               // Dictionary being iterated over
 111   uint _i;                      // Counter over the bins
 112   uint _j;                      // Counter inside each bin
 113  public:
 114   const void *_key, *_value;    // Easy access to the key-value pair
 115   DictI( const Dict *d ) {reset(d);}; // Create a new iterator
 116   void reset( const Dict *dict );     // Reset existing iterator
 117   void operator ++(void);             // Increment iterator
 118   int test(void) { return _i<_d->_size;} // Test for end of iteration
 119 };
 120 
 121 #endif // SHARE_VM_LIBADT_DICT_HPP