duke@435: /*
twisti@1573:  * Copyright 1997-2009 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: // A symbolOop is a canonicalized string.
duke@435: // All symbolOops reside in global symbolTable.
duke@435: // See oopFactory::new_symbol for how to allocate a symbolOop
duke@435: 
duke@435: class symbolOopDesc : public oopDesc {
duke@435:   friend class VMStructs;
duke@435:  private:
duke@435:   unsigned short _length; // number of UTF8 characters in the symbol
duke@435:   jbyte _body[1];
duke@435: 
duke@435:   enum {
duke@435:     // max_symbol_length is constrained by type of _length
duke@435:     max_symbol_length = (1 << 16) -1
duke@435:   };
duke@435:  public:
duke@435: 
duke@435:   // Low-level access (used with care, since not GC-safe)
duke@435:   jbyte* base() { return &_body[0]; }
duke@435: 
duke@435: 
duke@435:   // Returns the largest size symbol we can safely hold.
duke@435:   static int max_length() {
duke@435:     return max_symbol_length;
duke@435:   }
duke@435: 
duke@435:   static int object_size(int length) {
duke@435:     int size = header_size() + (sizeof(unsigned short) + length + HeapWordSize - 1) / HeapWordSize;
duke@435:     return align_object_size(size);
duke@435:   }
duke@435: 
duke@435:   int object_size() { return object_size(utf8_length()); }
duke@435: 
duke@435:   int byte_at(int index) const {
duke@435:     assert(index >=0 && index < _length, "symbol index overflow");
duke@435:     return ((symbolOopDesc*)this)->base()[index];
duke@435:   }
duke@435: 
duke@435:   void byte_at_put(int index, int value) {
duke@435:     assert(index >=0 && index < _length, "symbol index overflow");
duke@435:     ((symbolOopDesc*)this)->base()[index] = value;
duke@435:   }
duke@435: 
duke@435:   jbyte* bytes() { return base(); }
duke@435: 
duke@435:   int utf8_length() const { return _length; }
duke@435: 
duke@435:   void set_utf8_length(int len) { _length = len; }
duke@435: 
twisti@1573:   // Compares the symbol with a string.
duke@435:   bool equals(const char* str, int len) const;
twisti@1573:   bool equals(const char* str) const { return equals(str, (int) strlen(str)); }
twisti@1573: 
twisti@1573:   // Tests if the symbol starts with the given prefix.
twisti@1573:   bool starts_with(const char* prefix, int len) const;
twisti@1573:   bool starts_with(const char* prefix) const {
twisti@1573:     return starts_with(prefix, (int) strlen(prefix));
twisti@1573:   }
twisti@1573: 
twisti@1573:   // Tests if the symbol starts with the given prefix.
twisti@1573:   int index_of_at(int i, const char* str, int len) const;
twisti@1573:   int index_of_at(int i, const char* str) const {
twisti@1573:     return index_of_at(i, str, (int) strlen(str));
twisti@1573:   }
duke@435: 
duke@435:   // Three-way compare for sorting; returns -1/0/1 if receiver is </==/> than arg
duke@435:   // note that the ordering is not alfabetical
duke@435:   inline int fast_compare(symbolOop other) const;
duke@435: 
duke@435:   // Returns receiver converted to null-terminated UTF-8 string; string is
duke@435:   // allocated in resource area, or in the char buffer provided by caller.
duke@435:   char* as_C_string() const;
duke@435:   char* as_C_string(char* buf, int size) const;
duke@435:   // Use buf if needed buffer length is <= size.
duke@435:   char* as_C_string_flexible_buffer(Thread* t, char* buf, int size) const;
duke@435: 
duke@435: 
duke@435:   // Returns a null terminated utf8 string in a resource array
duke@435:   char* as_utf8() const { return as_C_string(); }
duke@435:   char* as_utf8_flexible_buffer(Thread* t, char* buf, int size) const {
duke@435:     return as_C_string_flexible_buffer(t, buf, size);
duke@435:   }
duke@435: 
duke@435:   jchar* as_unicode(int& length) const;
duke@435: 
duke@435:   // Treating this symbol as a class name, returns the Java name for the class.
duke@435:   // String is allocated in resource area if buffer is not provided.
duke@435:   // See Klass::external_name()
duke@435:   const char* as_klass_external_name() const;
duke@435:   const char* as_klass_external_name(char* buf, int size) const;
duke@435: 
duke@435:   bool object_is_parsable() const {
duke@435:     return (utf8_length() > 0 || (oop)this == Universe::emptySymbol());
duke@435:   }
duke@435: 
duke@435:   // Printing
duke@435:   void print_symbol_on(outputStream* st = NULL);
duke@435: };
duke@435: 
duke@435: 
duke@435: // Note: this comparison is used for vtable sorting only; it doesn't matter
duke@435: // what order it defines, as long as it is a total, time-invariant order
duke@435: // Since symbolOops are in permSpace, their relative order in memory never changes,
duke@435: // so use address comparison for speed
duke@435: int symbolOopDesc::fast_compare(symbolOop other) const {
duke@435:  return (((uintptr_t)this < (uintptr_t)other) ? -1
duke@435:    : ((uintptr_t)this == (uintptr_t) other) ? 0 : 1);
duke@435: }