Mercurial > hg > truffle
diff src/share/vm/oops/symbolOop.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | dd57230ba8fe |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/oops/symbolOop.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,118 @@ +/* + * 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); +}