Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright 1997-2005 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  *

  */

 // A symbolOop is a canonicalized string.

 // All symbolOops reside in global symbolTable.

 // See oopFactory::new_symbol for how to allocate a symbolOop

 class symbolOopDesc : public oopDesc {

   friend class VMStructs;

  private:

   unsigned short _length; // number of UTF8 characters in the symbol

   jbyte _body[1];

   enum {

     // max_symbol_length is constrained by type of _length

     max_symbol_length = (1 << 16) -1

   };

  public:

   // Low-level access (used with care, since not GC-safe)

   jbyte* base() { return &_body[0]; }

   // Returns the largest size symbol we can safely hold.

   static int max_length() {

     return max_symbol_length;

   }

   static int object_size(int length) {

     int size = header_size() + (sizeof(unsigned short) + length + HeapWordSize - 1) / HeapWordSize;

     return align_object_size(size);

   }

   int object_size() { return object_size(utf8_length()); }

   int byte_at(int index) const {

     assert(index >=0 && index < _length, "symbol index overflow");

     return ((symbolOopDesc*)this)->base()[index];

   }

   void byte_at_put(int index, int value) {

     assert(index >=0 && index < _length, "symbol index overflow");

     ((symbolOopDesc*)this)->base()[index] = value;

   }

   jbyte* bytes() { return base(); }

   int utf8_length() const { return _length; }

   void set_utf8_length(int len) { _length = len; }

   // Compares the symbol with a string

   bool equals(const char* str, int len) const;

   // Three-way compare for sorting; returns -1/0/1 if receiver is </==/> than arg

   // note that the ordering is not alfabetical

   inline int fast_compare(symbolOop other) const;

   // Returns receiver converted to null-terminated UTF-8 string; string is

   // allocated in resource area, or in the char buffer provided by caller.

   char* as_C_string() const;

   char* as_C_string(char* buf, int size) const;

   // Use buf if needed buffer length is <= size.

   char* as_C_string_flexible_buffer(Thread* t, char* buf, int size) const;

   // Returns a null terminated utf8 string in a resource array

   char* as_utf8() const { return as_C_string(); }

   char* as_utf8_flexible_buffer(Thread* t, char* buf, int size) const {

     return as_C_string_flexible_buffer(t, buf, size);

   }

   jchar* as_unicode(int& length) const;

   // Treating this symbol as a class name, returns the Java name for the class.

   // String is allocated in resource area if buffer is not provided.

   // See Klass::external_name()

   const char* as_klass_external_name() const;

   const char* as_klass_external_name(char* buf, int size) const;

   bool object_is_parsable() const {

     return (utf8_length() > 0 || (oop)this == Universe::emptySymbol());

   }

   // Printing

   void print_symbol_on(outputStream* st = NULL);

 };

 // Note: this comparison is used for vtable sorting only; it doesn't matter

 // what order it defines, as long as it is a total, time-invariant order

 // Since symbolOops are in permSpace, their relative order in memory never changes,

 // so use address comparison for speed

 int symbolOopDesc::fast_compare(symbolOop other) const {

  return (((uintptr_t)this < (uintptr_t)other) ? -1

    : ((uintptr_t)this == (uintptr_t) other) ? 0 : 1);

 }