1 /* 2 * Copyright (c) 1997, 2013, 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 "oops/symbol.hpp" 30 #include "runtime/atomic.inline.hpp" 31 #include "runtime/os.hpp" 32 #include "memory/allocation.inline.hpp" 33 #include "memory/resourceArea.hpp" 34 35 Symbol::Symbol(const u1* name, int length, int refcount) : _refcount(refcount), _length(length) { 36 _identity_hash = os::random(); 37 for (int i = 0; i < _length; i++) { 38 byte_at_put(i, name[i]); 39 } 40 } 41 42 void* Symbol::operator new(size_t sz, int len, TRAPS) { 43 int alloc_size = size(len)*HeapWordSize; 44 address res = (address) AllocateHeap(alloc_size, mtSymbol); 45 return res; 46 } 47 48 void* Symbol::operator new(size_t sz, int len, Arena* arena, TRAPS) { 49 int alloc_size = size(len)*HeapWordSize; 50 address res = (address)arena->Amalloc(alloc_size); 51 return res; 52 } 53 54 void* Symbol::operator new(size_t sz, int len, ClassLoaderData* loader_data, TRAPS) { 55 address res; 56 int alloc_size = size(len)*HeapWordSize; 57 res = (address) Metaspace::allocate(loader_data, size(len), true, 58 MetaspaceObj::SymbolType, CHECK_NULL); 59 return res; 60 } 61 62 void Symbol::operator delete(void *p) { 63 assert(((Symbol*)p)->refcount() == 0, "should not call this"); 64 FreeHeap(p); 65 } 66 67 // ------------------------------------------------------------------ 68 // Symbol::equals 69 // 70 // Compares the symbol with a string of the given length. 71 bool Symbol::equals(const char* str, int len) const { 72 int l = utf8_length(); 73 if (l != len) return false; 74 while (l-- > 0) { 75 if (str[l] != (char) byte_at(l)) 76 return false; 77 } 78 assert(l == -1, "we should be at the beginning"); 79 return true; 80 } 81 82 83 // ------------------------------------------------------------------ 84 // Symbol::starts_with 85 // 86 // Tests if the symbol starts with the specified prefix of the given 87 // length. 88 bool Symbol::starts_with(const char* prefix, int len) const { 89 if (len > utf8_length()) return false; 90 while (len-- > 0) { 91 if (prefix[len] != (char) byte_at(len)) 92 return false; 93 } 94 assert(len == -1, "we should be at the beginning"); 95 return true; 96 } 97 98 99 // ------------------------------------------------------------------ 100 // Symbol::index_of 101 // 102 // Finds if the given string is a substring of this symbol's utf8 bytes. 103 // Return -1 on failure. Otherwise return the first index where str occurs. 104 int Symbol::index_of_at(int i, const char* str, int len) const { 105 assert(i >= 0 && i <= utf8_length(), "oob"); 106 if (len <= 0) return 0; 107 char first_char = str[0]; 108 address bytes = (address) ((Symbol*)this)->base(); 109 address limit = bytes + utf8_length() - len; // inclusive limit 110 address scan = bytes + i; 111 if (scan > limit) 112 return -1; 113 for (; scan <= limit; scan++) { 114 scan = (address) memchr(scan, first_char, (limit + 1 - scan)); 115 if (scan == NULL) 116 return -1; // not found 117 assert(scan >= bytes+i && scan <= limit, "scan oob"); 118 if (memcmp(scan, str, len) == 0) 119 return (int)(scan - bytes); 120 } 121 return -1; 122 } 123 124 125 char* Symbol::as_C_string(char* buf, int size) const { 126 if (size > 0) { 127 int len = MIN2(size - 1, utf8_length()); 128 for (int i = 0; i < len; i++) { 129 buf[i] = byte_at(i); 130 } 131 buf[len] = '\0'; 132 } 133 return buf; 134 } 135 136 char* Symbol::as_C_string() const { 137 int len = utf8_length(); 138 char* str = NEW_RESOURCE_ARRAY(char, len + 1); 139 return as_C_string(str, len + 1); 140 } 141 142 char* Symbol::as_C_string_flexible_buffer(Thread* t, 143 char* buf, int size) const { 144 char* str; 145 int len = utf8_length(); 146 int buf_len = len + 1; 147 if (size < buf_len) { 148 str = NEW_RESOURCE_ARRAY(char, buf_len); 149 } else { 150 str = buf; 151 } 152 return as_C_string(str, buf_len); 153 } 154 155 void Symbol::print_symbol_on(outputStream* st) const { 156 ResourceMark rm; 157 st = st ? st : tty; 158 st->print("%s", as_quoted_ascii()); 159 } 160 161 char* Symbol::as_quoted_ascii() const { 162 const char *ptr = (const char *)&_body[0]; 163 int quoted_length = UTF8::quoted_ascii_length(ptr, utf8_length()); 164 char* result = NEW_RESOURCE_ARRAY(char, quoted_length + 1); 165 UTF8::as_quoted_ascii(ptr, utf8_length(), result, quoted_length + 1); 166 return result; 167 } 168 169 jchar* Symbol::as_unicode(int& length) const { 170 Symbol* this_ptr = (Symbol*)this; 171 length = UTF8::unicode_length((char*)this_ptr->bytes(), utf8_length()); 172 jchar* result = NEW_RESOURCE_ARRAY(jchar, length); 173 if (length > 0) { 174 UTF8::convert_to_unicode((char*)this_ptr->bytes(), result, length); 175 } 176 return result; 177 } 178 179 const char* Symbol::as_klass_external_name(char* buf, int size) const { 180 if (size > 0) { 181 char* str = as_C_string(buf, size); 182 int length = (int)strlen(str); 183 // Turn all '/'s into '.'s (also for array klasses) 184 for (int index = 0; index < length; index++) { 185 if (str[index] == '/') { 186 str[index] = '.'; 187 } 188 } 189 return str; 190 } else { 191 return buf; 192 } 193 } 194 195 const char* Symbol::as_klass_external_name() const { 196 char* str = as_C_string(); 197 int length = (int)strlen(str); 198 // Turn all '/'s into '.'s (also for array klasses) 199 for (int index = 0; index < length; index++) { 200 if (str[index] == '/') { 201 str[index] = '.'; 202 } 203 } 204 return str; 205 } 206 207 // Alternate hashing for unbalanced symbol tables. 208 unsigned int Symbol::new_hash(jint seed) { 209 ResourceMark rm; 210 // Use alternate hashing algorithm on this symbol. 211 return AltHashing::murmur3_32(seed, (const jbyte*)as_C_string(), utf8_length()); 212 } 213 214 void Symbol::increment_refcount() { 215 // Only increment the refcount if positive. If negative either 216 // overflow has occurred or it is a permanent symbol in a read only 217 // shared archive. 218 if (_refcount >= 0) { 219 Atomic::inc(&_refcount); 220 NOT_PRODUCT(Atomic::inc(&_total_count);) 221 } 222 } 223 224 void Symbol::decrement_refcount() { 225 if (_refcount >= 0) { 226 Atomic::dec(&_refcount); 227 #ifdef ASSERT 228 if (_refcount < 0) { 229 print(); 230 assert(false, "reference count underflow for symbol"); 231 } 232 #endif 233 } 234 } 235 236 void Symbol::print_on(outputStream* st) const { 237 if (this == NULL) { 238 st->print_cr("NULL"); 239 } else { 240 st->print("Symbol: '"); 241 print_symbol_on(st); 242 st->print("'"); 243 st->print(" count %d", refcount()); 244 } 245 } 246 247 // The print_value functions are present in all builds, to support the 248 // disassembler and error reporting. 249 void Symbol::print_value_on(outputStream* st) const { 250 if (this == NULL) { 251 st->print("NULL"); 252 } else { 253 st->print("'"); 254 for (int i = 0; i < utf8_length(); i++) { 255 st->print("%c", byte_at(i)); 256 } 257 st->print("'"); 258 } 259 } 260 261 // SymbolTable prints this in its statistics 262 NOT_PRODUCT(int Symbol::_total_count = 0;)