1 /*
2 * Copyright (c) 1997, 2016, 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 "classfile/altHashing.hpp"
28 #include "classfile/classLoaderData.hpp"
29 #include "memory/allocation.inline.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "oops/symbol.hpp"
32 #include "runtime/atomic.inline.hpp"
33 #include "runtime/os.hpp"
34
35 Symbol::Symbol(const u1* name, int length, int refcount) {
36 _refcount = refcount;
37 _length = length;
38 _identity_hash = (short)os::random();
39 for (int i = 0; i < _length; i++) {
40 byte_at_put(i, name[i]);
41 }
42 }
43
44 void* Symbol::operator new(size_t sz, int len, TRAPS) throw() {
45 int alloc_size = size(len)*wordSize;
46 address res = (address) AllocateHeap(alloc_size, mtSymbol);
47 return res;
48 }
49
50 void* Symbol::operator new(size_t sz, int len, Arena* arena, TRAPS) throw() {
51 int alloc_size = size(len)*wordSize;
52 address res = (address)arena->Amalloc_4(alloc_size);
53 return res;
54 }
55
56 void* Symbol::operator new(size_t sz, int len, ClassLoaderData* loader_data, TRAPS) throw() {
57 address res;
58 res = (address) Metaspace::allocate(loader_data, size(len), true,
59 MetaspaceObj::SymbolType, CHECK_NULL);
60 return res;
61 }
62
63 void Symbol::operator delete(void *p) {
64 assert(((Symbol*)p)->refcount() == 0, "should not call this");
65 FreeHeap(p);
66 }
67
68 // ------------------------------------------------------------------
69 // Symbol::equals
70 //
71 // Compares the symbol with a string of the given length.
72 bool Symbol::equals(const char* str, int len) const {
73 int l = utf8_length();
74 if (l != len) return false;
75 while (l-- > 0) {
76 if (str[l] != (char) byte_at(l))
77 return false;
78 }
79 assert(l == -1, "we should be at the beginning");
80 return true;
81 }
82
83
84 // ------------------------------------------------------------------
85 // Symbol::starts_with
86 //
87 // Tests if the symbol starts with the specified prefix of the given
88 // length.
89 bool Symbol::starts_with(const char* prefix, int len) const {
90 if (len > utf8_length()) return false;
91 while (len-- > 0) {
92 if (prefix[len] != (char) byte_at(len))
93 return false;
94 }
95 assert(len == -1, "we should be at the beginning");
96 return true;
97 }
98
99
100 // ------------------------------------------------------------------
101 // Symbol::index_of
102 //
103 // Finds if the given string is a substring of this symbol's utf8 bytes.
104 // Return -1 on failure. Otherwise return the first index where str occurs.
105 int Symbol::index_of_at(int i, const char* str, int len) const {
106 assert(i >= 0 && i <= utf8_length(), "oob");
107 if (len <= 0) return 0;
108 char first_char = str[0];
109 address bytes = (address) ((Symbol*)this)->base();
110 address limit = bytes + utf8_length() - len; // inclusive limit
111 address scan = bytes + i;
112 if (scan > limit)
113 return -1;
114 for (; scan <= limit; scan++) {
115 scan = (address) memchr(scan, first_char, (limit + 1 - scan));
116 if (scan == NULL)
117 return -1; // not found
118 assert(scan >= bytes+i && scan <= limit, "scan oob");
119 if (memcmp(scan, str, len) == 0)
120 return (int)(scan - bytes);
121 }
122 return -1;
123 }
124
125
126 char* Symbol::as_C_string(char* buf, int size) const {
127 if (size > 0) {
128 int len = MIN2(size - 1, utf8_length());
129 for (int i = 0; i < len; i++) {
130 buf[i] = byte_at(i);
131 }
132 buf[len] = '\0';
133 }
134 return buf;
135 }
136
137 char* Symbol::as_C_string() const {
138 int len = utf8_length();
139 char* str = NEW_RESOURCE_ARRAY(char, len + 1);
140 return as_C_string(str, len + 1);
141 }
142
143 char* Symbol::as_C_string_flexible_buffer(Thread* t,
144 char* buf, int size) const {
145 char* str;
146 int len = utf8_length();
147 int buf_len = len + 1;
148 if (size < buf_len) {
149 str = NEW_RESOURCE_ARRAY(char, buf_len);
150 } else {
151 str = buf;
152 }
153 return as_C_string(str, buf_len);
154 }
155
156 void Symbol::print_utf8_on(outputStream* st) const {
157 st->print("%s", as_C_string());
158 }
159
160 void Symbol::print_symbol_on(outputStream* st) const {
161 char *s;
162 st = st ? st : tty;
163 {
164 // ResourceMark may not affect st->print(). If st is a string
165 // stream it could resize, using the same resource arena.
166 ResourceMark rm;
167 s = as_quoted_ascii();
168 s = os::strdup(s);
169 }
170 st->print("%s", s);
171 os::free(s);
172 }
173
174 char* Symbol::as_quoted_ascii() const {
175 const char *ptr = (const char *)&_body[0];
176 int quoted_length = UTF8::quoted_ascii_length(ptr, utf8_length());
177 char* result = NEW_RESOURCE_ARRAY(char, quoted_length + 1);
178 UTF8::as_quoted_ascii(ptr, utf8_length(), result, quoted_length + 1);
179 return result;
180 }
181
182 jchar* Symbol::as_unicode(int& length) const {
183 Symbol* this_ptr = (Symbol*)this;
184 length = UTF8::unicode_length((char*)this_ptr->bytes(), utf8_length());
185 jchar* result = NEW_RESOURCE_ARRAY(jchar, length);
186 if (length > 0) {
187 UTF8::convert_to_unicode((char*)this_ptr->bytes(), result, length);
188 }
189 return result;
190 }
191
192 const char* Symbol::as_klass_external_name(char* buf, int size) const {
193 if (size > 0) {
194 char* str = as_C_string(buf, size);
195 int length = (int)strlen(str);
196 // Turn all '/'s into '.'s (also for array klasses)
197 for (int index = 0; index < length; index++) {
198 if (str[index] == '/') {
199 str[index] = '.';
200 }
201 }
202 return str;
203 } else {
204 return buf;
205 }
206 }
207
208 const char* Symbol::as_klass_external_name() const {
209 char* str = as_C_string();
210 int length = (int)strlen(str);
211 // Turn all '/'s into '.'s (also for array klasses)
212 for (int index = 0; index < length; index++) {
213 if (str[index] == '/') {
214 str[index] = '.';
215 }
216 }
217 return str;
218 }
219
220 // Alternate hashing for unbalanced symbol tables.
221 unsigned int Symbol::new_hash(juint seed) {
222 ResourceMark rm;
223 // Use alternate hashing algorithm on this symbol.
224 return AltHashing::murmur3_32(seed, (const jbyte*)as_C_string(), utf8_length());
225 }
226
227 void Symbol::increment_refcount() {
228 // Only increment the refcount if positive. If negative either
229 // overflow has occurred or it is a permanent symbol in a read only
230 // shared archive.
231 if (_refcount >= 0) {
232 Atomic::inc(&_refcount);
233 NOT_PRODUCT(Atomic::inc(&_total_count);)
234 }
235 }
236
237 void Symbol::decrement_refcount() {
238 if (_refcount >= 0) {
239 Atomic::dec(&_refcount);
240 #ifdef ASSERT
241 if (_refcount < 0) {
242 print();
243 assert(false, "reference count underflow for symbol");
244 }
245 #endif
246 }
247 }
248
249 void Symbol::print_on(outputStream* st) const {
250 if (this == NULL) {
251 st->print_cr("NULL");
252 } else {
253 st->print("Symbol: '");
254 print_symbol_on(st);
255 st->print("'");
256 st->print(" count %d", refcount());
257 }
258 }
259
260 // The print_value functions are present in all builds, to support the
261 // disassembler and error reporting.
262 void Symbol::print_value_on(outputStream* st) const {
263 if (this == NULL) {
264 st->print("NULL");
265 } else {
266 st->print("'");
267 for (int i = 0; i < utf8_length(); i++) {
268 st->print("%c", byte_at(i));
269 }
270 st->print("'");
271 }
272 }
273
274 // SymbolTable prints this in its statistics
275 NOT_PRODUCT(int Symbol::_total_count = 0;)