/*

 * Copyright (c) 1997, 2009, 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

 * questions.

 *

 */

// 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();

  }

};