Wed, 06 Jan 2010 22:21:39 -0800
Merge
1 /*
2 * Copyright 1997-2009 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 // A symbolOop is a canonicalized string.
26 // All symbolOops reside in global symbolTable.
27 // See oopFactory::new_symbol for how to allocate a symbolOop
29 class symbolOopDesc : public oopDesc {
30 friend class VMStructs;
31 private:
32 unsigned short _length; // number of UTF8 characters in the symbol
33 jbyte _body[1];
35 enum {
36 // max_symbol_length is constrained by type of _length
37 max_symbol_length = (1 << 16) -1
38 };
39 public:
41 // Low-level access (used with care, since not GC-safe)
42 jbyte* base() { return &_body[0]; }
45 // Returns the largest size symbol we can safely hold.
46 static int max_length() {
47 return max_symbol_length;
48 }
50 static int object_size(int length) {
51 int size = header_size() + (sizeof(unsigned short) + length + HeapWordSize - 1) / HeapWordSize;
52 return align_object_size(size);
53 }
55 int object_size() { return object_size(utf8_length()); }
57 int byte_at(int index) const {
58 assert(index >=0 && index < _length, "symbol index overflow");
59 return ((symbolOopDesc*)this)->base()[index];
60 }
62 void byte_at_put(int index, int value) {
63 assert(index >=0 && index < _length, "symbol index overflow");
64 ((symbolOopDesc*)this)->base()[index] = value;
65 }
67 jbyte* bytes() { return base(); }
69 int utf8_length() const { return _length; }
71 void set_utf8_length(int len) { _length = len; }
73 // Compares the symbol with a string.
74 bool equals(const char* str, int len) const;
75 bool equals(const char* str) const { return equals(str, (int) strlen(str)); }
77 // Tests if the symbol starts with the given prefix.
78 bool starts_with(const char* prefix, int len) const;
79 bool starts_with(const char* prefix) const {
80 return starts_with(prefix, (int) strlen(prefix));
81 }
83 // Tests if the symbol starts with the given prefix.
84 int index_of_at(int i, const char* str, int len) const;
85 int index_of_at(int i, const char* str) const {
86 return index_of_at(i, str, (int) strlen(str));
87 }
89 // Three-way compare for sorting; returns -1/0/1 if receiver is </==/> than arg
90 // note that the ordering is not alfabetical
91 inline int fast_compare(symbolOop other) const;
93 // Returns receiver converted to null-terminated UTF-8 string; string is
94 // allocated in resource area, or in the char buffer provided by caller.
95 char* as_C_string() const;
96 char* as_C_string(char* buf, int size) const;
97 // Use buf if needed buffer length is <= size.
98 char* as_C_string_flexible_buffer(Thread* t, char* buf, int size) const;
101 // Returns a null terminated utf8 string in a resource array
102 char* as_utf8() const { return as_C_string(); }
103 char* as_utf8_flexible_buffer(Thread* t, char* buf, int size) const {
104 return as_C_string_flexible_buffer(t, buf, size);
105 }
107 jchar* as_unicode(int& length) const;
109 // Treating this symbol as a class name, returns the Java name for the class.
110 // String is allocated in resource area if buffer is not provided.
111 // See Klass::external_name()
112 const char* as_klass_external_name() const;
113 const char* as_klass_external_name(char* buf, int size) const;
115 bool object_is_parsable() const {
116 return (utf8_length() > 0 || (oop)this == Universe::emptySymbol());
117 }
119 // Printing
120 void print_symbol_on(outputStream* st = NULL);
121 };
124 // Note: this comparison is used for vtable sorting only; it doesn't matter
125 // what order it defines, as long as it is a total, time-invariant order
126 // Since symbolOops are in permSpace, their relative order in memory never changes,
127 // so use address comparison for speed
128 int symbolOopDesc::fast_compare(symbolOop other) const {
129 return (((uintptr_t)this < (uintptr_t)other) ? -1
130 : ((uintptr_t)this == (uintptr_t) other) ? 0 : 1);
131 }