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comparison: src/share/vm/utilities/resourceHash.hpp
src/share/vm/utilities/resourceHash.hpp
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| 1 /* | |
| 2 * Copyright (c) 2012, 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_UTILITIES_RESOURCEHASH_HPP | |
| 26 #define SHARE_VM_UTILITIES_RESOURCEHASH_HPP | |
| 27 | |
| 28 #include "memory/allocation.hpp" | |
| 29 #include "utilities/top.hpp" | |
| 30 | |
| 31 template<typename K> struct ResourceHashtableFns { | |
| 32 typedef unsigned (*hash_fn)(K const&); | |
| 33 typedef bool (*equals_fn)(K const&, K const&); | |
| 34 }; | |
| 35 | |
| 36 template<typename K> unsigned primitive_hash(const K& k) { | |
| 37 unsigned hash = (unsigned)((uintptr_t)k); | |
| 38 return hash ^ (hash > 3); // just in case we're dealing with aligned ptrs | |
| 39 } | |
| 40 | |
| 41 template<typename K> bool primitive_equals(const K& k0, const K& k1) { | |
| 42 return k0 == k1; | |
| 43 } | |
| 44 | |
| 45 template< | |
| 46 typename K, typename V, | |
| 47 // xlC does not compile this: | |
| 48 // http://stackoverflow.com/questions/8532961/template-argument-of-type-that-is-defined-by-inner-typedef-from-other-template-c | |
| 49 //typename ResourceHashtableFns<K>::hash_fn HASH = primitive_hash<K>, | |
| 50 //typename ResourceHashtableFns<K>::equals_fn EQUALS = primitive_equals<K>, | |
| 51 unsigned (*HASH) (K const&) = primitive_hash<K>, | |
| 52 bool (*EQUALS)(K const&, K const&) = primitive_equals<K>, | |
| 53 unsigned SIZE = 256 | |
| 54 > | |
| 55 class ResourceHashtable : public ResourceObj { | |
| 56 private: | |
| 57 | |
| 58 class Node : public ResourceObj { | |
| 59 public: | |
| 60 unsigned _hash; | |
| 61 K _key; | |
| 62 V _value; | |
| 63 Node* _next; | |
| 64 | |
| 65 Node(unsigned hash, K const& key, V const& value) : | |
| 66 _hash(hash), _key(key), _value(value), _next(NULL) {} | |
| 67 }; | |
| 68 | |
| 69 Node* _table[SIZE]; | |
| 70 | |
| 71 // Returns a pointer to where the node where the value would reside if | |
| 72 // it's in the table. | |
| 73 Node** lookup_node(unsigned hash, K const& key) { | |
| 74 unsigned index = hash % SIZE; | |
| 75 Node** ptr = &_table[index]; | |
| 76 while (*ptr != NULL) { | |
| 77 Node* node = *ptr; | |
| 78 if (node->_hash == hash && EQUALS(key, node->_key)) { | |
| 79 break; | |
| 80 } | |
| 81 ptr = &(node->_next); | |
| 82 } | |
| 83 return ptr; | |
| 84 } | |
| 85 | |
| 86 Node const** lookup_node(unsigned hash, K const& key) const { | |
| 87 return const_cast<Node const**>( | |
| 88 const_cast<ResourceHashtable*>(this)->lookup_node(hash, key)); | |
| 89 } | |
| 90 | |
| 91 public: | |
| 92 ResourceHashtable() { memset(_table, 0, SIZE * sizeof(Node*)); } | |
| 93 | |
| 94 bool contains(K const& key) const { | |
| 95 return get(key) != NULL; | |
| 96 } | |
| 97 | |
| 98 V* get(K const& key) const { | |
| 99 unsigned hv = HASH(key); | |
| 100 Node const** ptr = lookup_node(hv, key); | |
| 101 if (*ptr != NULL) { | |
| 102 return const_cast<V*>(&(*ptr)->_value); | |
| 103 } else { | |
| 104 return NULL; | |
| 105 } | |
| 106 } | |
| 107 | |
| 108 // Inserts or replaces a value in the table | |
| 109 void put(K const& key, V const& value) { | |
| 110 unsigned hv = HASH(key); | |
| 111 Node** ptr = lookup_node(hv, key); | |
| 112 if (*ptr != NULL) { | |
| 113 (*ptr)->_value = value; | |
| 114 } else { | |
| 115 *ptr = new Node(hv, key, value); | |
| 116 } | |
| 117 } | |
| 118 | |
| 119 // ITER contains bool do_entry(K const&, V const&), which will be | |
| 120 // called for each entry in the table. If do_entry() returns false, | |
| 121 // the iteration is cancelled. | |
| 122 template<class ITER> | |
| 123 void iterate(ITER* iter) const { | |
| 124 Node* const* bucket = _table; | |
| 125 while (bucket < &_table[SIZE]) { | |
| 126 Node* node = *bucket; | |
| 127 while (node != NULL) { | |
| 128 bool cont = iter->do_entry(node->_key, node->_value); | |
| 129 if (!cont) { return; } | |
| 130 node = node->_next; | |
| 131 } | |
| 132 ++bucket; | |
| 133 } | |
| 134 } | |
| 135 }; | |
| 136 | |
| 137 | |
| 138 #endif // SHARE_VM_UTILITIES_RESOURCEHASH_HPP |
