1 /*
2 * Copyright (c) 1997, 2014, 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)*HeapWordSize;
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)*HeapWordSize;
52 address res = (address)arena->Amalloc(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 int alloc_size = size(len)*HeapWordSize;
59 res = (address) Metaspace::allocate(loader_data, size(len), true,
60 MetaspaceObj::SymbolType, CHECK_NULL);
61 return res;
62 }
63
64 void Symbol::operator delete(void *p) {
65 assert(((Symbol*)p)->refcount() == 0, "should not call this");
66 FreeHeap(p);
67 }
68
69 // ------------------------------------------------------------------
70 // Symbol::equals
71 //
72 // Compares the symbol with a string of the given length.
73 bool Symbol::equals(const char* str, int len) const {
74 int l = utf8_length();
75 if (l != len) return false;
76 while (l-- > 0) {
77 if (str[l] != (char) byte_at(l))
78 return false;
79 }
80 assert(l == -1, "we should be at the beginning");
81 return true;
82 }
83
84
85 // ------------------------------------------------------------------
86 // Symbol::starts_with
87 //
88 // Tests if the symbol starts with the specified prefix of the given
89 // length.
90 bool Symbol::starts_with(const char* prefix, int len) const {
91 if (len > utf8_length()) return false;
92 while (len-- > 0) {
93 if (prefix[len] != (char) byte_at(len))
94 return false;
95 }
96 assert(len == -1, "we should be at the beginning");
97 return true;
98 }
99
100
101 // ------------------------------------------------------------------
102 // Symbol::index_of
103 //
104 // Finds if the given string is a substring of this symbol's utf8 bytes.
105 // Return -1 on failure. Otherwise return the first index where str occurs.
106 int Symbol::index_of_at(int i, const char* str, int len) const {
107 assert(i >= 0 && i <= utf8_length(), "oob");
108 if (len <= 0) return 0;
109 char first_char = str[0];
110 address bytes = (address) ((Symbol*)this)->base();
111 address limit = bytes + utf8_length() - len; // inclusive limit
112 address scan = bytes + i;
113 if (scan > limit)
114 return -1;
115 for (; scan <= limit; scan++) {
116 scan = (address) memchr(scan, first_char, (limit + 1 - scan));
117 if (scan == NULL)
118 return -1; // not found
119 assert(scan >= bytes+i && scan <= limit, "scan oob");
120 if (memcmp(scan, str, len) == 0)
121 return (int)(scan - bytes);
122 }
123 return -1;
124 }
125
126
127 char* Symbol::as_C_string(char* buf, int size) const {
128 if (size > 0) {
129 int len = MIN2(size - 1, utf8_length());
130 for (int i = 0; i < len; i++) {
131 buf[i] = byte_at(i);
132 }
133 buf[len] = '\0';
134 }
135 return buf;
136 }
137
138 char* Symbol::as_C_string() const {
139 int len = utf8_length();
140 char* str = NEW_RESOURCE_ARRAY(char, len + 1);
141 return as_C_string(str, len + 1);
142 }
143
144 char* Symbol::as_C_string_flexible_buffer(Thread* t,
145 char* buf, int size) const {
146 char* str;
147 int len = utf8_length();
148 int buf_len = len + 1;
149 if (size < buf_len) {
150 str = NEW_RESOURCE_ARRAY(char, buf_len);
151 } else {
152 str = buf;
153 }
154 return as_C_string(str, buf_len);
155 }
156
157 void Symbol::print_utf8_on(outputStream* st) const {
158 st->print("%s", as_C_string());
159 }
160
161 void Symbol::print_symbol_on(outputStream* st) const {
162 ResourceMark rm;
163 st = st ? st : tty;
164 st->print("%s", as_quoted_ascii());
165 }
166
167 char* Symbol::as_quoted_ascii() const {
168 const char *ptr = (const char *)&_body[0];
169 int quoted_length = UTF8::quoted_ascii_length(ptr, utf8_length());
170 char* result = NEW_RESOURCE_ARRAY(char, quoted_length + 1);
171 UTF8::as_quoted_ascii(ptr, utf8_length(), result, quoted_length + 1);
172 return result;
173 }
174
175 jchar* Symbol::as_unicode(int& length) const {
176 Symbol* this_ptr = (Symbol*)this;
177 length = UTF8::unicode_length((char*)this_ptr->bytes(), utf8_length());
178 jchar* result = NEW_RESOURCE_ARRAY(jchar, length);
179 if (length > 0) {
180 UTF8::convert_to_unicode((char*)this_ptr->bytes(), result, length);
181 }
182 return result;
183 }
184
185 const char* Symbol::as_klass_external_name(char* buf, int size) const {
186 if (size > 0) {
187 char* str = as_C_string(buf, size);
188 int length = (int)strlen(str);
189 // Turn all '/'s into '.'s (also for array klasses)
190 for (int index = 0; index < length; index++) {
191 if (str[index] == '/') {
192 str[index] = '.';
193 }
194 }
195 return str;
196 } else {
197 return buf;
198 }
199 }
200
201 const char* Symbol::as_klass_external_name() const {
202 char* str = as_C_string();
203 int length = (int)strlen(str);
204 // Turn all '/'s into '.'s (also for array klasses)
205 for (int index = 0; index < length; index++) {
206 if (str[index] == '/') {
207 str[index] = '.';
208 }
209 }
210 return str;
211 }
212
213 // Alternate hashing for unbalanced symbol tables.
214 unsigned int Symbol::new_hash(juint seed) {
215 ResourceMark rm;
216 // Use alternate hashing algorithm on this symbol.
217 return AltHashing::murmur3_32(seed, (const jbyte*)as_C_string(), utf8_length());
218 }
219
220 void Symbol::increment_refcount() {
221 // Only increment the refcount if positive. If negative either
222 // overflow has occurred or it is a permanent symbol in a read only
223 // shared archive.
224 if (_refcount >= 0) {
225 Atomic::inc(&_refcount);
226 NOT_PRODUCT(Atomic::inc(&_total_count);)
227 }
228 }
229
230 void Symbol::decrement_refcount() {
231 if (_refcount >= 0) {
232 Atomic::dec(&_refcount);
233 #ifdef ASSERT
234 if (_refcount < 0) {
235 print();
236 assert(false, "reference count underflow for symbol");
237 }
238 #endif
239 }
240 }
241
242 void Symbol::print_on(outputStream* st) const {
243 if (this == NULL) {
244 st->print_cr("NULL");
245 } else {
246 st->print("Symbol: '");
247 print_symbol_on(st);
248 st->print("'");
249 st->print(" count %d", refcount());
250 }
251 }
252
253 // The print_value functions are present in all builds, to support the
254 // disassembler and error reporting.
255 void Symbol::print_value_on(outputStream* st) const {
256 if (this == NULL) {
257 st->print("NULL");
258 } else {
259 st->print("'");
260 for (int i = 0; i < utf8_length(); i++) {
261 st->print("%c", byte_at(i));
262 }
263 st->print("'");
264 }
265 }
266
267 // SymbolTable prints this in its statistics
268 NOT_PRODUCT(int Symbol::_total_count = 0;)