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 /*

  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

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  */

 #ifndef SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP

 #define SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP

 #include "memory/allocation.inline.hpp"

 #include "oops/symbolOop.hpp"

 #include "utilities/hashtable.hpp"

 // The symbol table holds all symbolOops and corresponding interned strings.

 // symbolOops and literal strings should be canonicalized.

 //

 // The interned strings are created lazily.

 //

 // It is implemented as an open hash table with a fixed number of buckets.

 //

 // %note:

 //  - symbolTableEntrys are allocated in blocks to reduce the space overhead.

 class BoolObjectClosure;

 class SymbolTable : public Hashtable {

   friend class VMStructs;

 private:

   // The symbol table

   static SymbolTable* _the_table;

   // Adding elements

   symbolOop basic_add(int index, u1* name, int len,

                       unsigned int hashValue, TRAPS);

   bool basic_add(constantPoolHandle cp, int names_count,

                  const char** names, int* lengths, int* cp_indices,

                  unsigned int* hashValues, TRAPS);

   // Table size

   enum {

     symbol_table_size = 20011

   };

   symbolOop lookup(int index, const char* name, int len, unsigned int hash);

   SymbolTable()

     : Hashtable(symbol_table_size, sizeof (HashtableEntry)) {}

   SymbolTable(HashtableBucket* t, int number_of_entries)

     : Hashtable(symbol_table_size, sizeof (HashtableEntry), t,

                 number_of_entries) {}

 public:

   enum {

     symbol_alloc_batch_size = 8

   };

   // The symbol table

   static SymbolTable* the_table() { return _the_table; }

   static void create_table() {

     assert(_the_table == NULL, "One symbol table allowed.");

     _the_table = new SymbolTable();

   }

   static void create_table(HashtableBucket* t, int length,

                            int number_of_entries) {

     assert(_the_table == NULL, "One symbol table allowed.");

     assert(length == symbol_table_size * sizeof(HashtableBucket),

            "bad shared symbol size.");

     _the_table = new SymbolTable(t, number_of_entries);

   }

   static symbolOop lookup(const char* name, int len, TRAPS);

   // lookup only, won't add. Also calculate hash.

   static symbolOop lookup_only(const char* name, int len, unsigned int& hash);

   // Only copy to C string to be added if lookup failed.

   static symbolOop lookup(symbolHandle sym, int begin, int end, TRAPS);

   // jchar (utf16) version of lookups

   static symbolOop lookup_unicode(const jchar* name, int len, TRAPS);

   static symbolOop lookup_only_unicode(const jchar* name, int len, unsigned int& hash);

   static void add(constantPoolHandle cp, int names_count,

                   const char** names, int* lengths, int* cp_indices,

                   unsigned int* hashValues, TRAPS);

   // GC support

   //   Delete pointers to otherwise-unreachable objects.

   static void unlink(BoolObjectClosure* cl) {

     the_table()->Hashtable::unlink(cl);

   }

   // Invoke "f->do_oop" on the locations of all oops in the table.

   static void oops_do(OopClosure* f) {

     the_table()->Hashtable::oops_do(f);

   }

   // Symbol lookup

   static symbolOop lookup(int index, const char* name, int len, TRAPS);

   // Needed for preloading classes in signatures when compiling.

   // Returns the symbol is already present in symbol table, otherwise

   // NULL.  NO ALLOCATION IS GUARANTEED!

   static symbolOop probe(const char* name, int len) {

     unsigned int ignore_hash;

     return lookup_only(name, len, ignore_hash);

   }

   static symbolOop probe_unicode(const jchar* name, int len) {

     unsigned int ignore_hash;

     return lookup_only_unicode(name, len, ignore_hash);

   }

   // Histogram

   static void print_histogram()     PRODUCT_RETURN;

   // Debugging

   static void verify();

   // Sharing

   static void copy_buckets(char** top, char*end) {

     the_table()->Hashtable::copy_buckets(top, end);

   }

   static void copy_table(char** top, char*end) {

     the_table()->Hashtable::copy_table(top, end);

   }

   static void reverse(void* boundary = NULL) {

     ((Hashtable*)the_table())->reverse(boundary);

   }

 };

 class StringTable : public Hashtable {

   friend class VMStructs;

 private:

   // The string table

   static StringTable* _the_table;

   static oop intern(Handle string_or_null, jchar* chars, int length, TRAPS);

   oop basic_add(int index, Handle string_or_null, jchar* name, int len,

                 unsigned int hashValue, TRAPS);

   // Table size

   enum {

     string_table_size = 1009

   };

   oop lookup(int index, jchar* chars, int length, unsigned int hashValue);

   StringTable() : Hashtable(string_table_size, sizeof (HashtableEntry)) {}

   StringTable(HashtableBucket* t, int number_of_entries)

     : Hashtable(string_table_size, sizeof (HashtableEntry), t,

                 number_of_entries) {}

 public:

   // The string table

   static StringTable* the_table() { return _the_table; }

   static void create_table() {

     assert(_the_table == NULL, "One string table allowed.");

     _the_table = new StringTable();

   }

   static void create_table(HashtableBucket* t, int length,

                            int number_of_entries) {

     assert(_the_table == NULL, "One string table allowed.");

     assert(length == string_table_size * sizeof(HashtableBucket),

            "bad shared string size.");

     _the_table = new StringTable(t, number_of_entries);

   }

   static int hash_string(jchar* s, int len);

   // GC support

   //   Delete pointers to otherwise-unreachable objects.

   static void unlink(BoolObjectClosure* cl) {

     the_table()->Hashtable::unlink(cl);

   }

   // Invoke "f->do_oop" on the locations of all oops in the table.

   static void oops_do(OopClosure* f) {

     the_table()->Hashtable::oops_do(f);

   }

   // Probing

   static oop lookup(symbolOop symbol);

   // Interning

   static oop intern(symbolOop symbol, TRAPS);

   static oop intern(oop string, TRAPS);

   static oop intern(const char *utf8_string, TRAPS);

   // Debugging

   static void verify();

   // Sharing

   static void copy_buckets(char** top, char*end) {

     the_table()->Hashtable::copy_buckets(top, end);

   }

   static void copy_table(char** top, char*end) {

     the_table()->Hashtable::copy_table(top, end);

   }

   static void reverse() {

     ((BasicHashtable*)the_table())->reverse();

   }

 };

 #endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP