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comparison src/share/vm/oops/symbol.cpp @ 2177:3582bf76420e

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6990754: Use native memory and reference counting to implement SymbolTable Summary: move symbols from permgen into C heap and reference count them Reviewed-by: never, acorn, jmasa, stefank
author coleenp
date Thu, 27 Jan 2011 16:11:27 -0800
parents src/share/vm/oops/symbolOop.cpp@f95d63e2154a
children 1d1603768966
comparison
equal deleted inserted replaced
2176:27e4ea99855d 2177:3582bf76420e
1 /*
2 * Copyright (c) 1997, 2009, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25
26 #include "precompiled.hpp"
27 #include "oops/oop.inline.hpp"
28 #include "oops/symbol.hpp"
29 #include "runtime/os.hpp"
30 #include "memory/allocation.inline.hpp"
31
32 Symbol::Symbol(const u1* name, int length) : _refcount(0), _length(length) {
33 _identity_hash = os::random();
34 for (int i = 0; i < _length; i++) {
35 byte_at_put(i, name[i]);
36 }
37 }
38
39 void* Symbol::operator new(size_t size, int len) {
40 return (void *) AllocateHeap(object_size(len) * HeapWordSize, "symbol");
41 }
42
43 // ------------------------------------------------------------------
44 // Symbol::equals
45 //
46 // Compares the symbol with a string of the given length.
47 bool Symbol::equals(const char* str, int len) const {
48 int l = utf8_length();
49 if (l != len) return false;
50 while (l-- > 0) {
51 if (str[l] != (char) byte_at(l))
52 return false;
53 }
54 assert(l == -1, "we should be at the beginning");
55 return true;
56 }
57
58
59 // ------------------------------------------------------------------
60 // Symbol::starts_with
61 //
62 // Tests if the symbol starts with the specified prefix of the given
63 // length.
64 bool Symbol::starts_with(const char* prefix, int len) const {
65 if (len > utf8_length()) return false;
66 while (len-- > 0) {
67 if (prefix[len] != (char) byte_at(len))
68 return false;
69 }
70 assert(len == -1, "we should be at the beginning");
71 return true;
72 }
73
74
75 // ------------------------------------------------------------------
76 // Symbol::index_of
77 //
78 // Finds if the given string is a substring of this symbol's utf8 bytes.
79 // Return -1 on failure. Otherwise return the first index where str occurs.
80 int Symbol::index_of_at(int i, const char* str, int len) const {
81 assert(i >= 0 && i <= utf8_length(), "oob");
82 if (len <= 0) return 0;
83 char first_char = str[0];
84 address bytes = (address) ((Symbol*)this)->base();
85 address limit = bytes + utf8_length() - len; // inclusive limit
86 address scan = bytes + i;
87 if (scan > limit)
88 return -1;
89 for (;;) {
90 scan = (address) memchr(scan, first_char, (limit + 1 - scan));
91 if (scan == NULL)
92 return -1; // not found
93 assert(scan >= bytes+i && scan <= limit, "scan oob");
94 if (memcmp(scan, str, len) == 0)
95 return (int)(scan - bytes);
96 }
97 }
98
99
100 char* Symbol::as_C_string(char* buf, int size) const {
101 if (size > 0) {
102 int len = MIN2(size - 1, utf8_length());
103 for (int i = 0; i < len; i++) {
104 buf[i] = byte_at(i);
105 }
106 buf[len] = '\0';
107 }
108 return buf;
109 }
110
111 char* Symbol::as_C_string() const {
112 int len = utf8_length();
113 char* str = NEW_RESOURCE_ARRAY(char, len + 1);
114 return as_C_string(str, len + 1);
115 }
116
117 char* Symbol::as_C_string_flexible_buffer(Thread* t,
118 char* buf, int size) const {
119 char* str;
120 int len = utf8_length();
121 int buf_len = len + 1;
122 if (size < buf_len) {
123 str = NEW_RESOURCE_ARRAY(char, buf_len);
124 } else {
125 str = buf;
126 }
127 return as_C_string(str, buf_len);
128 }
129
130 void Symbol::print_symbol_on(outputStream* st) const {
131 st = st ? st : tty;
132 int length = UTF8::unicode_length((const char*)bytes(), utf8_length());
133 const char *ptr = (const char *)bytes();
134 jchar value;
135 for (int index = 0; index < length; index++) {
136 ptr = UTF8::next(ptr, &value);
137 if (value >= 32 && value < 127 || value == '\'' || value == '\\') {
138 st->put(value);
139 } else {
140 st->print("\\u%04x", value);
141 }
142 }
143 }
144
145 jchar* Symbol::as_unicode(int& length) const {
146 Symbol* this_ptr = (Symbol*)this;
147 length = UTF8::unicode_length((char*)this_ptr->bytes(), utf8_length());
148 jchar* result = NEW_RESOURCE_ARRAY(jchar, length);
149 if (length > 0) {
150 UTF8::convert_to_unicode((char*)this_ptr->bytes(), result, length);
151 }
152 return result;
153 }
154
155 const char* Symbol::as_klass_external_name(char* buf, int size) const {
156 if (size > 0) {
157 char* str = as_C_string(buf, size);
158 int length = (int)strlen(str);
159 // Turn all '/'s into '.'s (also for array klasses)
160 for (int index = 0; index < length; index++) {
161 if (str[index] == '/') {
162 str[index] = '.';
163 }
164 }
165 return str;
166 } else {
167 return buf;
168 }
169 }
170
171 const char* Symbol::as_klass_external_name() const {
172 char* str = as_C_string();
173 int length = (int)strlen(str);
174 // Turn all '/'s into '.'s (also for array klasses)
175 for (int index = 0; index < length; index++) {
176 if (str[index] == '/') {
177 str[index] = '.';
178 }
179 }
180 return str;
181 }
182
183
184 void Symbol::print_on(outputStream* st) const {
185 if (this == NULL) {
186 st->print_cr("NULL");
187 } else {
188 st->print("Symbol: '");
189 print_symbol_on(st);
190 st->print("'");
191 st->print(" count %d", refcount());
192 }
193 }
194
195 // The print_value functions are present in all builds, to support the
196 // disassembler and error reporting.
197 void Symbol::print_value_on(outputStream* st) const {
198 if (this == NULL) {
199 st->print("NULL");
200 } else {
201 st->print("'");
202 for (int i = 0; i < utf8_length(); i++) {
203 st->print("%c", byte_at(i));
204 }
205 st->print("'");
206 }
207 }
208
209 void Symbol::increment_refcount() {
210 // Only increment the refcount if positive. If negative either
211 // overflow has occurred or it is a permanent symbol in a read only
212 // shared archive.
213 if (_refcount >= 0) {
214 Atomic::inc(&_refcount);
215 NOT_PRODUCT(Atomic::inc(&_total_count);)
216 }
217 }
218
219 void Symbol::decrement_refcount() {
220 if (_refcount >= 0) {
221 Atomic::dec(&_refcount);
222 #ifdef ASSERT
223 if (_refcount < 0) {
224 print();
225 assert(false, "reference count underflow for symbol");
226 }
227 #endif
228 }
229 }
230
231 NOT_PRODUCT(int Symbol::_total_count = 0;)