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;)