• file
• revisions
• annotate
• diff
• comparison
• raw

src/share/vm/utilities/resourceHash.hpp@f90c822e73f8 (annotated)

src/share/vm/utilities/resourceHash.hpp

Wed, 27 Apr 2016 01:25:04 +0800

author

aoqi

date

Wed, 27 Apr 2016 01:25:04 +0800

changeset 0

f90c822e73f8

child 6876

710a3c8b516e

permissions

-rw-r--r--

Initial load
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/
changeset: 6782:28b50d07f6f8
tag: jdk8u25-b17

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation.
aoqi@0	8	*
aoqi@0	9	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	12	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	13	* accompanied this code).
aoqi@0	14	*
aoqi@0	15	* You should have received a copy of the GNU General Public License version
aoqi@0	16	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	18	*
aoqi@0	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	20	* or visit www.oracle.com if you need additional information or have any
aoqi@0	21	* questions.
aoqi@0	22	*
aoqi@0	23	*/
aoqi@0	24
aoqi@0	25	#ifndef SHARE_VM_UTILITIES_RESOURCEHASH_HPP
aoqi@0	26	#define SHARE_VM_UTILITIES_RESOURCEHASH_HPP
aoqi@0	27
aoqi@0	28	#include "memory/allocation.hpp"
aoqi@0	29	#include "utilities/top.hpp"
aoqi@0	30
aoqi@0	31	template<typename K> struct ResourceHashtableFns {
aoqi@0	32	typedef unsigned (*hash_fn)(K const&);
aoqi@0	33	typedef bool (*equals_fn)(K const&, K const&);
aoqi@0	34	};
aoqi@0	35
aoqi@0	36	template<typename K> unsigned primitive_hash(const K& k) {
aoqi@0	37	unsigned hash = (unsigned)((uintptr_t)k);
aoqi@0	38	return hash ^ (hash > 3); // just in case we're dealing with aligned ptrs
aoqi@0	39	}
aoqi@0	40
aoqi@0	41	template<typename K> bool primitive_equals(const K& k0, const K& k1) {
aoqi@0	42	return k0 == k1;
aoqi@0	43	}
aoqi@0	44
aoqi@0	45	template<
aoqi@0	46	typename K, typename V,
aoqi@0	47	// xlC does not compile this:
aoqi@0	48	// http://stackoverflow.com/questions/8532961/template-argument-of-type-that-is-defined-by-inner-typedef-from-other-template-c
aoqi@0	49	//typename ResourceHashtableFns<K>::hash_fn HASH = primitive_hash<K>,
aoqi@0	50	//typename ResourceHashtableFns<K>::equals_fn EQUALS = primitive_equals<K>,
aoqi@0	51	unsigned (*HASH) (K const&) = primitive_hash<K>,
aoqi@0	52	bool (*EQUALS)(K const&, K const&) = primitive_equals<K>,
aoqi@0	53	unsigned SIZE = 256
aoqi@0	54	>
aoqi@0	55	class ResourceHashtable : public ResourceObj {
aoqi@0	56	private:
aoqi@0	57
aoqi@0	58	class Node : public ResourceObj {
aoqi@0	59	public:
aoqi@0	60	unsigned _hash;
aoqi@0	61	K _key;
aoqi@0	62	V _value;
aoqi@0	63	Node* _next;
aoqi@0	64
aoqi@0	65	Node(unsigned hash, K const& key, V const& value) :
aoqi@0	66	_hash(hash), _key(key), _value(value), _next(NULL) {}
aoqi@0	67	};
aoqi@0	68
aoqi@0	69	Node* _table[SIZE];
aoqi@0	70
aoqi@0	71	// Returns a pointer to where the node where the value would reside if
aoqi@0	72	// it's in the table.
aoqi@0	73	Node** lookup_node(unsigned hash, K const& key) {
aoqi@0	74	unsigned index = hash % SIZE;
aoqi@0	75	Node** ptr = &_table[index];
aoqi@0	76	while (*ptr != NULL) {
aoqi@0	77	Node* node = *ptr;
aoqi@0	78	if (node->_hash == hash && EQUALS(key, node->_key)) {
aoqi@0	79	break;
aoqi@0	80	}
aoqi@0	81	ptr = &(node->_next);
aoqi@0	82	}
aoqi@0	83	return ptr;
aoqi@0	84	}
aoqi@0	85
aoqi@0	86	Node const** lookup_node(unsigned hash, K const& key) const {
aoqi@0	87	return const_cast<Node const**>(
aoqi@0	88	const_cast<ResourceHashtable*>(this)->lookup_node(hash, key));
aoqi@0	89	}
aoqi@0	90
aoqi@0	91	public:
aoqi@0	92	ResourceHashtable() { memset(_table, 0, SIZE * sizeof(Node*)); }
aoqi@0	93
aoqi@0	94	bool contains(K const& key) const {
aoqi@0	95	return get(key) != NULL;
aoqi@0	96	}
aoqi@0	97
aoqi@0	98	V* get(K const& key) const {
aoqi@0	99	unsigned hv = HASH(key);
aoqi@0	100	Node const** ptr = lookup_node(hv, key);
aoqi@0	101	if (*ptr != NULL) {
aoqi@0	102	return const_cast<V*>(&(*ptr)->_value);
aoqi@0	103	} else {
aoqi@0	104	return NULL;
aoqi@0	105	}
aoqi@0	106	}
aoqi@0	107
aoqi@0	108	// Inserts or replaces a value in the table
aoqi@0	109	void put(K const& key, V const& value) {
aoqi@0	110	unsigned hv = HASH(key);
aoqi@0	111	Node** ptr = lookup_node(hv, key);
aoqi@0	112	if (*ptr != NULL) {
aoqi@0	113	(*ptr)->_value = value;
aoqi@0	114	} else {
aoqi@0	115	*ptr = new Node(hv, key, value);
aoqi@0	116	}
aoqi@0	117	}
aoqi@0	118
aoqi@0	119	// ITER contains bool do_entry(K const&, V const&), which will be
aoqi@0	120	// called for each entry in the table. If do_entry() returns false,
aoqi@0	121	// the iteration is cancelled.
aoqi@0	122	template<class ITER>
aoqi@0	123	void iterate(ITER* iter) const {
aoqi@0	124	Node* const* bucket = _table;
aoqi@0	125	while (bucket < &_table[SIZE]) {
aoqi@0	126	Node* node = *bucket;
aoqi@0	127	while (node != NULL) {
aoqi@0	128	bool cont = iter->do_entry(node->_key, node->_value);
aoqi@0	129	if (!cont) { return; }
aoqi@0	130	node = node->_next;
aoqi@0	131	}
aoqi@0	132	++bucket;
aoqi@0	133	}
aoqi@0	134	}
aoqi@0	135	};
aoqi@0	136
aoqi@0	137
aoqi@0	138	#endif // SHARE_VM_UTILITIES_RESOURCEHASH_HPP