1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/utilities/resourceHash.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,138 @@
1.4 +/*
1.5 + * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_UTILITIES_RESOURCEHASH_HPP
1.29 +#define SHARE_VM_UTILITIES_RESOURCEHASH_HPP
1.30 +
1.31 +#include "memory/allocation.hpp"
1.32 +#include "utilities/top.hpp"
1.33 +
1.34 +template<typename K> struct ResourceHashtableFns {
1.35 + typedef unsigned (*hash_fn)(K const&);
1.36 + typedef bool (*equals_fn)(K const&, K const&);
1.37 +};
1.38 +
1.39 +template<typename K> unsigned primitive_hash(const K& k) {
1.40 + unsigned hash = (unsigned)((uintptr_t)k);
1.41 + return hash ^ (hash > 3); // just in case we're dealing with aligned ptrs
1.42 +}
1.43 +
1.44 +template<typename K> bool primitive_equals(const K& k0, const K& k1) {
1.45 + return k0 == k1;
1.46 +}
1.47 +
1.48 +template<
1.49 + typename K, typename V,
1.50 + // xlC does not compile this:
1.51 + // http://stackoverflow.com/questions/8532961/template-argument-of-type-that-is-defined-by-inner-typedef-from-other-template-c
1.52 + //typename ResourceHashtableFns<K>::hash_fn HASH = primitive_hash<K>,
1.53 + //typename ResourceHashtableFns<K>::equals_fn EQUALS = primitive_equals<K>,
1.54 + unsigned (*HASH) (K const&) = primitive_hash<K>,
1.55 + bool (*EQUALS)(K const&, K const&) = primitive_equals<K>,
1.56 + unsigned SIZE = 256
1.57 + >
1.58 +class ResourceHashtable : public ResourceObj {
1.59 + private:
1.60 +
1.61 + class Node : public ResourceObj {
1.62 + public:
1.63 + unsigned _hash;
1.64 + K _key;
1.65 + V _value;
1.66 + Node* _next;
1.67 +
1.68 + Node(unsigned hash, K const& key, V const& value) :
1.69 + _hash(hash), _key(key), _value(value), _next(NULL) {}
1.70 + };
1.71 +
1.72 + Node* _table[SIZE];
1.73 +
1.74 + // Returns a pointer to where the node where the value would reside if
1.75 + // it's in the table.
1.76 + Node** lookup_node(unsigned hash, K const& key) {
1.77 + unsigned index = hash % SIZE;
1.78 + Node** ptr = &_table[index];
1.79 + while (*ptr != NULL) {
1.80 + Node* node = *ptr;
1.81 + if (node->_hash == hash && EQUALS(key, node->_key)) {
1.82 + break;
1.83 + }
1.84 + ptr = &(node->_next);
1.85 + }
1.86 + return ptr;
1.87 + }
1.88 +
1.89 + Node const** lookup_node(unsigned hash, K const& key) const {
1.90 + return const_cast<Node const**>(
1.91 + const_cast<ResourceHashtable*>(this)->lookup_node(hash, key));
1.92 + }
1.93 +
1.94 + public:
1.95 + ResourceHashtable() { memset(_table, 0, SIZE * sizeof(Node*)); }
1.96 +
1.97 + bool contains(K const& key) const {
1.98 + return get(key) != NULL;
1.99 + }
1.100 +
1.101 + V* get(K const& key) const {
1.102 + unsigned hv = HASH(key);
1.103 + Node const** ptr = lookup_node(hv, key);
1.104 + if (*ptr != NULL) {
1.105 + return const_cast<V*>(&(*ptr)->_value);
1.106 + } else {
1.107 + return NULL;
1.108 + }
1.109 + }
1.110 +
1.111 + // Inserts or replaces a value in the table
1.112 + void put(K const& key, V const& value) {
1.113 + unsigned hv = HASH(key);
1.114 + Node** ptr = lookup_node(hv, key);
1.115 + if (*ptr != NULL) {
1.116 + (*ptr)->_value = value;
1.117 + } else {
1.118 + *ptr = new Node(hv, key, value);
1.119 + }
1.120 + }
1.121 +
1.122 + // ITER contains bool do_entry(K const&, V const&), which will be
1.123 + // called for each entry in the table. If do_entry() returns false,
1.124 + // the iteration is cancelled.
1.125 + template<class ITER>
1.126 + void iterate(ITER* iter) const {
1.127 + Node* const* bucket = _table;
1.128 + while (bucket < &_table[SIZE]) {
1.129 + Node* node = *bucket;
1.130 + while (node != NULL) {
1.131 + bool cont = iter->do_entry(node->_key, node->_value);
1.132 + if (!cont) { return; }
1.133 + node = node->_next;
1.134 + }
1.135 + ++bucket;
1.136 + }
1.137 + }
1.138 +};
1.139 +
1.140 +
1.141 +#endif // SHARE_VM_UTILITIES_RESOURCEHASH_HPP
