jdk8-mips64-public/hotspot: src/share/vm/utilities/hashtable.inline.hpp@f4f596978298

     1 /*

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     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.

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     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

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    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

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    25 // Inline function definitions for hashtable.hpp.

    28 // --------------------------------------------------------------------------

    29 // Hash function

    31 // We originally used hashpjw, but hash P(31) gives just as good results

    32 // and is slighly faster. We would like a hash function that looks at every

    33 // character, since package names have large common prefixes, and also because

    34 // hash_or_fail does error checking while iterating.

    36 // hash P(31) from Kernighan & Ritchie

    38 inline unsigned int Hashtable::hash_symbol(const char* s, int len) {

    39   unsigned int h = 0;

    40   while (len-- > 0) {

    41     h = 31*h + (unsigned) *s;

    42     s++;

    43   }

    44   return h;

    45 }

    48 // --------------------------------------------------------------------------

    50 // Initialize a table.

    52 inline BasicHashtable::BasicHashtable(int table_size, int entry_size) {

    53   // Called on startup, no locking needed

    54   initialize(table_size, entry_size, 0);

    55   _buckets = NEW_C_HEAP_ARRAY(HashtableBucket, table_size);

    56   for (int index = 0; index < _table_size; index++) {

    57     _buckets[index].clear();

    58   }

    59 }

    62 inline BasicHashtable::BasicHashtable(int table_size, int entry_size,

    63                                       HashtableBucket* buckets,

    64                                       int number_of_entries) {

    65   // Called on startup, no locking needed

    66   initialize(table_size, entry_size, number_of_entries);

    67   _buckets = buckets;

    68 }

    71 inline void BasicHashtable::initialize(int table_size, int entry_size,

    72                                        int number_of_entries) {

    73   // Called on startup, no locking needed

    74   _table_size = table_size;

    75   _entry_size = entry_size;

    76   _free_list = NULL;

    77   _first_free_entry = NULL;

    78   _end_block = NULL;

    79   _number_of_entries = number_of_entries;

    80 #ifdef ASSERT

    81   _lookup_count = 0;

    82   _lookup_length = 0;

    83 #endif

    84 }

    87 // The following method is MT-safe and may be used with caution.

    88 inline BasicHashtableEntry* BasicHashtable::bucket(int i) {

    89   return _buckets[i].get_entry();

    90 }

    93 inline void HashtableBucket::set_entry(BasicHashtableEntry* l) {

    94   // Warning: Preserve store ordering.  The SystemDictionary is read

    95   //          without locks.  The new SystemDictionaryEntry must be

    96   //          complete before other threads can be allowed to see it

    97   //          via a store to _buckets[index].

    98   OrderAccess::release_store_ptr(&_entry, l);

    99 }

   102 inline BasicHashtableEntry* HashtableBucket::get_entry() const {

   103   // Warning: Preserve load ordering.  The SystemDictionary is read

   104   //          without locks.  The new SystemDictionaryEntry must be

   105   //          complete before other threads can be allowed to see it

   106   //          via a store to _buckets[index].

   107   return (BasicHashtableEntry*) OrderAccess::load_ptr_acquire(&_entry);

   108 }

   111 inline void BasicHashtable::set_entry(int index, BasicHashtableEntry* entry) {

   112   _buckets[index].set_entry(entry);

   113 }

   116 inline void BasicHashtable::add_entry(int index, BasicHashtableEntry* entry) {

   117   entry->set_next(bucket(index));

   118   _buckets[index].set_entry(entry);

   119   ++_number_of_entries;

   120 }

   122 inline void BasicHashtable::free_entry(BasicHashtableEntry* entry) {

   123   entry->set_next(_free_list);

   124   _free_list = entry;

   125   --_number_of_entries;

   126 }

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