Mercurial > hg > truffle
comparison 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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1 /* | |
2 * Copyright 1997-2005 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 */ | |
24 | |
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 | |
28 | |
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]; | |
34 | |
35 enum { | |
36 // max_symbol_length is constrained by type of _length | |
37 max_symbol_length = (1 << 16) -1 | |
38 }; | |
39 public: | |
40 | |
41 // Low-level access (used with care, since not GC-safe) | |
42 jbyte* base() { return &_body[0]; } | |
43 | |
44 | |
45 // Returns the largest size symbol we can safely hold. | |
46 static int max_length() { | |
47 return max_symbol_length; | |
48 } | |
49 | |
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 } | |
54 | |
55 int object_size() { return object_size(utf8_length()); } | |
56 | |
57 int byte_at(int index) const { | |
58 assert(index >=0 && index < _length, "symbol index overflow"); | |
59 return ((symbolOopDesc*)this)->base()[index]; | |
60 } | |
61 | |
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 } | |
66 | |
67 jbyte* bytes() { return base(); } | |
68 | |
69 int utf8_length() const { return _length; } | |
70 | |
71 void set_utf8_length(int len) { _length = len; } | |
72 | |
73 // Compares the symbol with a string | |
74 bool equals(const char* str, int len) const; | |
75 | |
76 // Three-way compare for sorting; returns -1/0/1 if receiver is </==/> than arg | |
77 // note that the ordering is not alfabetical | |
78 inline int fast_compare(symbolOop other) const; | |
79 | |
80 // Returns receiver converted to null-terminated UTF-8 string; string is | |
81 // allocated in resource area, or in the char buffer provided by caller. | |
82 char* as_C_string() const; | |
83 char* as_C_string(char* buf, int size) const; | |
84 // Use buf if needed buffer length is <= size. | |
85 char* as_C_string_flexible_buffer(Thread* t, char* buf, int size) const; | |
86 | |
87 | |
88 // Returns a null terminated utf8 string in a resource array | |
89 char* as_utf8() const { return as_C_string(); } | |
90 char* as_utf8_flexible_buffer(Thread* t, char* buf, int size) const { | |
91 return as_C_string_flexible_buffer(t, buf, size); | |
92 } | |
93 | |
94 jchar* as_unicode(int& length) const; | |
95 | |
96 // Treating this symbol as a class name, returns the Java name for the class. | |
97 // String is allocated in resource area if buffer is not provided. | |
98 // See Klass::external_name() | |
99 const char* as_klass_external_name() const; | |
100 const char* as_klass_external_name(char* buf, int size) const; | |
101 | |
102 bool object_is_parsable() const { | |
103 return (utf8_length() > 0 || (oop)this == Universe::emptySymbol()); | |
104 } | |
105 | |
106 // Printing | |
107 void print_symbol_on(outputStream* st = NULL); | |
108 }; | |
109 | |
110 | |
111 // Note: this comparison is used for vtable sorting only; it doesn't matter | |
112 // what order it defines, as long as it is a total, time-invariant order | |
113 // Since symbolOops are in permSpace, their relative order in memory never changes, | |
114 // so use address comparison for speed | |
115 int symbolOopDesc::fast_compare(symbolOop other) const { | |
116 return (((uintptr_t)this < (uintptr_t)other) ? -1 | |
117 : ((uintptr_t)this == (uintptr_t) other) ? 0 : 1); | |
118 } |