Mercurial > jdk8-mips64-public > hotspot / file comparison
comparison: src/share/vm/classfile/symbolTable.cpp
src/share/vm/classfile/symbolTable.cpp
- changeset 2700
- 352622fd140a
- parent 2661
- b099aaf51bf8
- child 3427
- 94ec88ca68e2
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| 2698:38fea01eb669 | 2700:352622fd140a |
|---|---|
| 1 /* | 1 /* |
| 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. | 2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved. |
| 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | 4 * |
| 5 * This code is free software; you can redistribute it and/or modify it | 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 | 6 * under the terms of the GNU General Public License version 2 only, as |
| 7 * published by the Free Software Foundation. | 7 * published by the Free Software Foundation. |
| 478 }; | 478 }; |
| 479 #endif | 479 #endif |
| 480 | 480 |
| 481 | 481 |
| 482 // -------------------------------------------------------------------------- | 482 // -------------------------------------------------------------------------- |
| 483 | |
| 484 | |
| 485 // Compute the hash value for a java.lang.String object which would | |
| 486 // contain the characters passed in. This hash value is used for at | |
| 487 // least two purposes. | |
| 488 // | |
| 489 // (a) As the hash value used by the StringTable for bucket selection | |
| 490 // and comparison (stored in the HashtableEntry structures). This | |
| 491 // is used in the String.intern() method. | |
| 492 // | |
| 493 // (b) As the hash value used by the String object itself, in | |
| 494 // String.hashCode(). This value is normally calculate in Java code | |
| 495 // in the String.hashCode method(), but is precomputed for String | |
| 496 // objects in the shared archive file. | |
| 497 // | |
| 498 // For this reason, THIS ALGORITHM MUST MATCH String.hashCode(). | |
| 499 | |
| 500 int StringTable::hash_string(jchar* s, int len) { | |
| 501 unsigned h = 0; | |
| 502 while (len-- > 0) { | |
| 503 h = 31*h + (unsigned) *s; | |
| 504 s++; | |
| 505 } | |
| 506 return h; | |
| 507 } | |
| 508 | |
| 509 | |
| 510 StringTable* StringTable::_the_table = NULL; | 483 StringTable* StringTable::_the_table = NULL; |
| 511 | 484 |
| 512 oop StringTable::lookup(int index, jchar* name, | 485 oop StringTable::lookup(int index, jchar* name, |
| 513 int len, unsigned int hash) { | 486 int len, unsigned int hash) { |
| 514 for (HashtableEntry<oop>* l = bucket(index); l != NULL; l = l->next()) { | 487 for (HashtableEntry<oop>* l = bucket(index); l != NULL; l = l->next()) { |
| 559 | 532 |
| 560 oop StringTable::lookup(Symbol* symbol) { | 533 oop StringTable::lookup(Symbol* symbol) { |
| 561 ResourceMark rm; | 534 ResourceMark rm; |
| 562 int length; | 535 int length; |
| 563 jchar* chars = symbol->as_unicode(length); | 536 jchar* chars = symbol->as_unicode(length); |
| 564 unsigned int hashValue = hash_string(chars, length); | 537 unsigned int hashValue = java_lang_String::hash_string(chars, length); |
| 565 int index = the_table()->hash_to_index(hashValue); | 538 int index = the_table()->hash_to_index(hashValue); |
| 566 return the_table()->lookup(index, chars, length, hashValue); | 539 return the_table()->lookup(index, chars, length, hashValue); |
| 567 } | 540 } |
| 568 | 541 |
| 569 | 542 |
| 570 oop StringTable::intern(Handle string_or_null, jchar* name, | 543 oop StringTable::intern(Handle string_or_null, jchar* name, |
| 571 int len, TRAPS) { | 544 int len, TRAPS) { |
| 572 unsigned int hashValue = hash_string(name, len); | 545 unsigned int hashValue = java_lang_String::hash_string(name, len); |
| 573 int index = the_table()->hash_to_index(hashValue); | 546 int index = the_table()->hash_to_index(hashValue); |
| 574 oop string = the_table()->lookup(index, name, len, hashValue); | 547 oop string = the_table()->lookup(index, name, len, hashValue); |
| 575 | 548 |
| 576 // Found | 549 // Found |
| 577 if (string != NULL) return string; | 550 if (string != NULL) return string; |
| 661 HashtableEntry<oop>* p = the_table()->bucket(i); | 634 HashtableEntry<oop>* p = the_table()->bucket(i); |
| 662 for ( ; p != NULL; p = p->next()) { | 635 for ( ; p != NULL; p = p->next()) { |
| 663 oop s = p->literal(); | 636 oop s = p->literal(); |
| 664 guarantee(s != NULL, "interned string is NULL"); | 637 guarantee(s != NULL, "interned string is NULL"); |
| 665 guarantee(s->is_perm() || !JavaObjectsInPerm, "interned string not in permspace"); | 638 guarantee(s->is_perm() || !JavaObjectsInPerm, "interned string not in permspace"); |
| 666 | 639 unsigned int h = java_lang_String::hash_string(s); |
| 667 int length; | |
| 668 jchar* chars = java_lang_String::as_unicode_string(s, length); | |
| 669 unsigned int h = hash_string(chars, length); | |
| 670 guarantee(p->hash() == h, "broken hash in string table entry"); | 640 guarantee(p->hash() == h, "broken hash in string table entry"); |
| 671 guarantee(the_table()->hash_to_index(h) == i, | 641 guarantee(the_table()->hash_to_index(h) == i, |
| 672 "wrong index in string table"); | 642 "wrong index in string table"); |
| 673 } | 643 } |
| 674 } | 644 } |
