duke@435: /*
xdono@631:  * Copyright 1997-2008 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: // A constantPool is an array containing class constants as described in the
duke@435: // class file.
duke@435: //
duke@435: // Most of the constant pool entries are written during class parsing, which
duke@435: // is safe.  For klass and string types, the constant pool entry is
duke@435: // modified when the entry is resolved.  If a klass or string constant pool
duke@435: // entry is read without a lock, only the resolved state guarantees that
duke@435: // the entry in the constant pool is a klass or String object and
duke@435: // not a symbolOop.
duke@435: 
duke@435: class SymbolHashMap;
duke@435: 
coleenp@548: class constantPoolOopDesc : public oopDesc {
duke@435:   friend class VMStructs;
duke@435:   friend class BytecodeInterpreter;  // Directly extracts an oop in the pool for fast instanceof/checkcast
duke@435:  private:
duke@435:   typeArrayOop         _tags; // the tag array describing the constant pool's contents
duke@435:   constantPoolCacheOop _cache;         // the cache holding interpreter runtime information
duke@435:   klassOop             _pool_holder;   // the corresponding class
coleenp@548:   int                  _length; // number of elements in the array
duke@435:   // only set to non-zero if constant pool is merged by RedefineClasses
duke@435:   int                  _orig_length;
duke@435: 
duke@435:   void set_tags(typeArrayOop tags)             { oop_store_without_check((oop*)&_tags, tags); }
duke@435:   void tag_at_put(int which, jbyte t)          { tags()->byte_at_put(which, t); }
duke@435:   void release_tag_at_put(int which, jbyte t)  { tags()->release_byte_at_put(which, t); }
duke@435: 
duke@435:  private:
duke@435:   intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(constantPoolOopDesc)); }
duke@435:   oop* tags_addr()       { return (oop*)&_tags; }
duke@435:   oop* cache_addr()      { return (oop*)&_cache; }
duke@435: 
duke@435:   oop* obj_at_addr(int which) const {
duke@435:     assert(is_within_bounds(which), "index out of bounds");
duke@435:     return (oop*) &base()[which];
duke@435:   }
duke@435: 
duke@435:   jint* int_at_addr(int which) const {
duke@435:     assert(is_within_bounds(which), "index out of bounds");
duke@435:     return (jint*) &base()[which];
duke@435:   }
duke@435: 
duke@435:   jlong* long_at_addr(int which) const {
duke@435:     assert(is_within_bounds(which), "index out of bounds");
duke@435:     return (jlong*) &base()[which];
duke@435:   }
duke@435: 
duke@435:   jfloat* float_at_addr(int which) const {
duke@435:     assert(is_within_bounds(which), "index out of bounds");
duke@435:     return (jfloat*) &base()[which];
duke@435:   }
duke@435: 
duke@435:   jdouble* double_at_addr(int which) const {
duke@435:     assert(is_within_bounds(which), "index out of bounds");
duke@435:     return (jdouble*) &base()[which];
duke@435:   }
duke@435: 
duke@435:  public:
duke@435:   typeArrayOop tags() const                 { return _tags; }
duke@435: 
duke@435:   // Klass holding pool
duke@435:   klassOop pool_holder() const              { return _pool_holder; }
duke@435:   void set_pool_holder(klassOop k)          { oop_store_without_check((oop*)&_pool_holder, (oop) k); }
duke@435:   oop* pool_holder_addr()                   { return (oop*)&_pool_holder; }
duke@435: 
duke@435:   // Interpreter runtime support
duke@435:   constantPoolCacheOop cache() const        { return _cache; }
duke@435:   void set_cache(constantPoolCacheOop cache){ oop_store((oop*)&_cache, cache); }
duke@435: 
duke@435:   // Assembly code support
duke@435:   static int tags_offset_in_bytes()         { return offset_of(constantPoolOopDesc, _tags); }
duke@435:   static int cache_offset_in_bytes()        { return offset_of(constantPoolOopDesc, _cache); }
duke@435:   static int pool_holder_offset_in_bytes()  { return offset_of(constantPoolOopDesc, _pool_holder); }
duke@435: 
duke@435:   // Storing constants
duke@435: 
duke@435:   void klass_at_put(int which, klassOop k) {
duke@435:     oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k));
duke@435:     // The interpreter assumes when the tag is stored, the klass is resolved
duke@435:     // and the klassOop is a klass rather than a symbolOop, so we need
duke@435:     // hardware store ordering here.
duke@435:     release_tag_at_put(which, JVM_CONSTANT_Class);
duke@435:     if (UseConcMarkSweepGC) {
duke@435:       // In case the earlier card-mark was consumed by a concurrent
duke@435:       // marking thread before the tag was updated, redirty the card.
duke@435:       oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k));
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   // For temporary use while constructing constant pool
duke@435:   void klass_index_at_put(int which, int name_index) {
duke@435:     tag_at_put(which, JVM_CONSTANT_ClassIndex);
duke@435:     *int_at_addr(which) = name_index;
duke@435:   }
duke@435: 
duke@435:   // Temporary until actual use
duke@435:   void unresolved_klass_at_put(int which, symbolOop s) {
duke@435:     // Overwrite the old index with a GC friendly value so
duke@435:     // that if GC looks during the transition it won't try
duke@435:     // to treat a small integer as oop.
duke@435:     *obj_at_addr(which) = NULL;
duke@435:     release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass);
duke@435:     oop_store_without_check(obj_at_addr(which), oop(s));
duke@435:   }
duke@435: 
duke@435:   // Temporary until actual use
duke@435:   void unresolved_string_at_put(int which, symbolOop s) {
duke@435:     *obj_at_addr(which) = NULL;
duke@435:     release_tag_at_put(which, JVM_CONSTANT_UnresolvedString);
duke@435:     oop_store_without_check(obj_at_addr(which), oop(s));
duke@435:   }
duke@435: 
duke@435:   void int_at_put(int which, jint i) {
duke@435:     tag_at_put(which, JVM_CONSTANT_Integer);
duke@435:     *int_at_addr(which) = i;
duke@435:   }
duke@435: 
duke@435:   void long_at_put(int which, jlong l) {
duke@435:     tag_at_put(which, JVM_CONSTANT_Long);
duke@435:     // *long_at_addr(which) = l;
duke@435:     Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l));
duke@435:   }
duke@435: 
duke@435:   void float_at_put(int which, jfloat f) {
duke@435:     tag_at_put(which, JVM_CONSTANT_Float);
duke@435:     *float_at_addr(which) = f;
duke@435:   }
duke@435: 
duke@435:   void double_at_put(int which, jdouble d) {
duke@435:     tag_at_put(which, JVM_CONSTANT_Double);
duke@435:     // *double_at_addr(which) = d;
duke@435:     // u8 temp = *(u8*) &d;
duke@435:     Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d));
duke@435:   }
duke@435: 
duke@435:   void symbol_at_put(int which, symbolOop s) {
duke@435:     tag_at_put(which, JVM_CONSTANT_Utf8);
duke@435:     oop_store_without_check(obj_at_addr(which), oop(s));
duke@435:   }
duke@435: 
duke@435:   void string_at_put(int which, oop str) {
duke@435:     oop_store((volatile oop*)obj_at_addr(which), str);
duke@435:     release_tag_at_put(which, JVM_CONSTANT_String);
duke@435:     if (UseConcMarkSweepGC) {
duke@435:       // In case the earlier card-mark was consumed by a concurrent
duke@435:       // marking thread before the tag was updated, redirty the card.
duke@435:       oop_store_without_check((volatile oop *)obj_at_addr(which), str);
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   // For temporary use while constructing constant pool
duke@435:   void string_index_at_put(int which, int string_index) {
duke@435:     tag_at_put(which, JVM_CONSTANT_StringIndex);
duke@435:     *int_at_addr(which) = string_index;
duke@435:   }
duke@435: 
duke@435:   void field_at_put(int which, int class_index, int name_and_type_index) {
duke@435:     tag_at_put(which, JVM_CONSTANT_Fieldref);
duke@435:     *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
duke@435:   }
duke@435: 
duke@435:   void method_at_put(int which, int class_index, int name_and_type_index) {
duke@435:     tag_at_put(which, JVM_CONSTANT_Methodref);
duke@435:     *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
duke@435:   }
duke@435: 
duke@435:   void interface_method_at_put(int which, int class_index, int name_and_type_index) {
duke@435:     tag_at_put(which, JVM_CONSTANT_InterfaceMethodref);
duke@435:     *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;  // Not so nice
duke@435:   }
duke@435: 
duke@435:   void name_and_type_at_put(int which, int name_index, int signature_index) {
duke@435:     tag_at_put(which, JVM_CONSTANT_NameAndType);
duke@435:     *int_at_addr(which) = ((jint) signature_index<<16) | name_index;  // Not so nice
duke@435:   }
duke@435: 
duke@435:   // Tag query
duke@435: 
duke@435:   constantTag tag_at(int which) const { return (constantTag)tags()->byte_at_acquire(which); }
duke@435: 
duke@435:   // Whether the entry is a pointer that must be GC'd.
duke@435:   bool is_pointer_entry(int which) {
duke@435:     constantTag tag = tag_at(which);
duke@435:     return tag.is_klass() ||
duke@435:       tag.is_unresolved_klass() ||
duke@435:       tag.is_symbol() ||
duke@435:       tag.is_unresolved_string() ||
duke@435:       tag.is_string();
duke@435:   }
duke@435: 
duke@435:   // Fetching constants
duke@435: 
duke@435:   klassOop klass_at(int which, TRAPS) {
duke@435:     constantPoolHandle h_this(THREAD, this);
duke@435:     return klass_at_impl(h_this, which, CHECK_NULL);
duke@435:   }
duke@435: 
duke@435:   symbolOop klass_name_at(int which);  // Returns the name, w/o resolving.
duke@435: 
duke@435:   klassOop resolved_klass_at(int which) {  // Used by Compiler
duke@435:     guarantee(tag_at(which).is_klass(), "Corrupted constant pool");
duke@435:     // Must do an acquire here in case another thread resolved the klass
duke@435:     // behind our back, lest we later load stale values thru the oop.
duke@435:     return klassOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which)));
duke@435:   }
duke@435: 
duke@435:   // This method should only be used with a cpool lock or during parsing or gc
duke@435:   symbolOop unresolved_klass_at(int which) {     // Temporary until actual use
duke@435:     symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which)));
duke@435:     // check that the klass is still unresolved.
duke@435:     assert(tag_at(which).is_unresolved_klass(), "Corrupted constant pool");
duke@435:     return s;
duke@435:   }
duke@435: 
duke@435:   // RedefineClasses() API support:
duke@435:   symbolOop klass_at_noresolve(int which) { return klass_name_at(which); }
duke@435: 
duke@435:   jint int_at(int which) {
duke@435:     assert(tag_at(which).is_int(), "Corrupted constant pool");
duke@435:     return *int_at_addr(which);
duke@435:   }
duke@435: 
duke@435:   jlong long_at(int which) {
duke@435:     assert(tag_at(which).is_long(), "Corrupted constant pool");
duke@435:     // return *long_at_addr(which);
duke@435:     u8 tmp = Bytes::get_native_u8((address)&base()[which]);
duke@435:     return *((jlong*)&tmp);
duke@435:   }
duke@435: 
duke@435:   jfloat float_at(int which) {
duke@435:     assert(tag_at(which).is_float(), "Corrupted constant pool");
duke@435:     return *float_at_addr(which);
duke@435:   }
duke@435: 
duke@435:   jdouble double_at(int which) {
duke@435:     assert(tag_at(which).is_double(), "Corrupted constant pool");
duke@435:     u8 tmp = Bytes::get_native_u8((address)&base()[which]);
duke@435:     return *((jdouble*)&tmp);
duke@435:   }
duke@435: 
duke@435:   symbolOop symbol_at(int which) {
duke@435:     assert(tag_at(which).is_utf8(), "Corrupted constant pool");
duke@435:     return symbolOop(*obj_at_addr(which));
duke@435:   }
duke@435: 
duke@435:   oop string_at(int which, TRAPS) {
duke@435:     constantPoolHandle h_this(THREAD, this);
duke@435:     return string_at_impl(h_this, which, CHECK_NULL);
duke@435:   }
duke@435: 
duke@435:   // only called when we are sure a string entry is already resolved (via an
duke@435:   // earlier string_at call.
duke@435:   oop resolved_string_at(int which) {
duke@435:     assert(tag_at(which).is_string(), "Corrupted constant pool");
duke@435:     // Must do an acquire here in case another thread resolved the klass
duke@435:     // behind our back, lest we later load stale values thru the oop.
duke@435:     return (oop)OrderAccess::load_ptr_acquire(obj_at_addr(which));
duke@435:   }
duke@435: 
duke@435:   // This method should only be used with a cpool lock or during parsing or gc
duke@435:   symbolOop unresolved_string_at(int which) {    // Temporary until actual use
duke@435:     symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which)));
duke@435:     // check that the string is still unresolved.
duke@435:     assert(tag_at(which).is_unresolved_string(), "Corrupted constant pool");
duke@435:     return s;
duke@435:   }
duke@435: 
duke@435:   // Returns an UTF8 for a CONSTANT_String entry at a given index.
duke@435:   // UTF8 char* representation was chosen to avoid conversion of
duke@435:   // java_lang_Strings at resolved entries into symbolOops
duke@435:   // or vice versa.
duke@435:   char* string_at_noresolve(int which);
duke@435: 
duke@435:   jint name_and_type_at(int which) {
duke@435:     assert(tag_at(which).is_name_and_type(), "Corrupted constant pool");
duke@435:     return *int_at_addr(which);
duke@435:   }
duke@435: 
duke@435:   // The following methods (klass_ref_at, klass_ref_at_noresolve, name_ref_at,
duke@435:   // signature_ref_at, klass_ref_index_at, name_and_type_ref_index_at,
duke@435:   // name_ref_index_at, signature_ref_index_at) all expect constant pool indices
duke@435:   // from the bytecodes to be passed in, which are actually potentially byte-swapped
duke@435:   // contstant pool cache indices. See field_or_method_at.
duke@435: 
duke@435:   // Lookup for entries consisting of (klass_index, name_and_type index)
duke@435:   klassOop klass_ref_at(int which, TRAPS);
duke@435:   symbolOop klass_ref_at_noresolve(int which);
duke@435:   symbolOop name_ref_at(int which);
duke@435:   symbolOop signature_ref_at(int which);    // the type descriptor
duke@435: 
duke@435:   int klass_ref_index_at(int which);
duke@435:   int name_and_type_ref_index_at(int which);
duke@435: 
duke@435:   // Lookup for entries consisting of (name_index, signature_index)
duke@435:   int name_ref_index_at(int which);
duke@435:   int signature_ref_index_at(int which);
duke@435: 
duke@435:   BasicType basic_type_for_signature_at(int which);
duke@435: 
duke@435:   // Resolve string constants (to prevent allocation during compilation)
duke@435:   void resolve_string_constants(TRAPS) {
duke@435:     constantPoolHandle h_this(THREAD, this);
duke@435:     resolve_string_constants_impl(h_this, CHECK);
duke@435:   }
duke@435: 
duke@435:   // Klass name matches name at offset
duke@435:   bool klass_name_at_matches(instanceKlassHandle k, int which);
duke@435: 
duke@435:   // Sizing
coleenp@548:   int length() const                   { return _length; }
coleenp@548:   void set_length(int length)          { _length = length; }
coleenp@548: 
coleenp@548:   // Tells whether index is within bounds.
coleenp@548:   bool is_within_bounds(int index) const {
coleenp@548:     return 0 <= index && index < length();
coleenp@548:   }
coleenp@548: 
duke@435:   static int header_size()             { return sizeof(constantPoolOopDesc)/HeapWordSize; }
duke@435:   static int object_size(int length)   { return align_object_size(header_size() + length); }
duke@435:   int object_size()                    { return object_size(length()); }
duke@435: 
duke@435:   friend class constantPoolKlass;
duke@435:   friend class ClassFileParser;
duke@435:   friend class SystemDictionary;
duke@435: 
duke@435:   // Used by compiler to prevent classloading.
duke@435:   static klassOop klass_at_if_loaded          (constantPoolHandle this_oop, int which);
duke@435:   static klassOop klass_ref_at_if_loaded      (constantPoolHandle this_oop, int which);
duke@435:   // Same as above - but does LinkResolving.
duke@435:   static klassOop klass_ref_at_if_loaded_check(constantPoolHandle this_oop, int which, TRAPS);
duke@435: 
duke@435:   // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
duke@435:   // future by other Java code. These take constant pool indices rather than possibly-byte-swapped
duke@435:   // constant pool cache indices as do the peer methods above.
duke@435:   symbolOop uncached_name_ref_at(int which);
duke@435:   symbolOop uncached_signature_ref_at(int which);
duke@435:   int       uncached_klass_ref_index_at(int which);
duke@435:   int       uncached_name_and_type_ref_index_at(int which);
duke@435: 
duke@435:   // Sharing
duke@435:   int pre_resolve_shared_klasses(TRAPS);
duke@435:   void shared_symbols_iterate(OopClosure* closure0);
duke@435:   void shared_tags_iterate(OopClosure* closure0);
duke@435:   void shared_strings_iterate(OopClosure* closure0);
duke@435: 
duke@435:   // Debugging
duke@435:   const char* printable_name_at(int which) PRODUCT_RETURN0;
duke@435: 
duke@435:  private:
duke@435: 
duke@435:   // Takes either a constant pool cache index in possibly byte-swapped
duke@435:   // byte order (which comes from the bytecodes after rewriting) or,
duke@435:   // if "uncached" is true, a vanilla constant pool index
duke@435:   jint field_or_method_at(int which, bool uncached) {
duke@435:     int i = -1;
duke@435:     if (uncached || cache() == NULL) {
duke@435:       i = which;
duke@435:     } else {
duke@435:       // change byte-ordering and go via cache
duke@435:       i = cache()->entry_at(Bytes::swap_u2(which))->constant_pool_index();
duke@435:     }
duke@435:     assert(tag_at(i).is_field_or_method(), "Corrupted constant pool");
duke@435:     return *int_at_addr(i);
duke@435:   }
duke@435: 
duke@435:   // Used while constructing constant pool (only by ClassFileParser)
duke@435:   jint klass_index_at(int which) {
duke@435:     assert(tag_at(which).is_klass_index(), "Corrupted constant pool");
duke@435:     return *int_at_addr(which);
duke@435:   }
duke@435: 
duke@435:   jint string_index_at(int which) {
duke@435:     assert(tag_at(which).is_string_index(), "Corrupted constant pool");
duke@435:     return *int_at_addr(which);
duke@435:   }
duke@435: 
duke@435:   // Performs the LinkResolver checks
duke@435:   static void verify_constant_pool_resolve(constantPoolHandle this_oop, KlassHandle klass, TRAPS);
duke@435: 
duke@435:   // Implementation of methods that needs an exposed 'this' pointer, in order to
duke@435:   // handle GC while executing the method
duke@435:   static klassOop klass_at_impl(constantPoolHandle this_oop, int which, TRAPS);
duke@435:   static oop string_at_impl(constantPoolHandle this_oop, int which, TRAPS);
duke@435: 
duke@435:   // Resolve string constants (to prevent allocation during compilation)
duke@435:   static void resolve_string_constants_impl(constantPoolHandle this_oop, TRAPS);
duke@435: 
duke@435:  public:
duke@435:   // Merging constantPoolOop support:
duke@435:   bool compare_entry_to(int index1, constantPoolHandle cp2, int index2, TRAPS);
duke@435:   void copy_cp_to(int start_i, int end_i, constantPoolHandle to_cp, int to_i,
duke@435:     TRAPS);
duke@435:   void copy_entry_to(int from_i, constantPoolHandle to_cp, int to_i, TRAPS);
duke@435:   int  find_matching_entry(int pattern_i, constantPoolHandle search_cp, TRAPS);
duke@435:   int  orig_length() const                { return _orig_length; }
duke@435:   void set_orig_length(int orig_length)   { _orig_length = orig_length; }
duke@435: 
duke@435: 
duke@435:   // JVMTI accesss - GetConstantPool, RetransformClasses, ...
duke@435:   friend class JvmtiConstantPoolReconstituter;
duke@435: 
duke@435:  private:
duke@435:   jint cpool_entry_size(jint idx);
duke@435:   jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap);
duke@435: 
duke@435:   // Copy cpool bytes into byte array.
duke@435:   // Returns:
duke@435:   //  int > 0, count of the raw cpool bytes that have been copied
duke@435:   //        0, OutOfMemory error
duke@435:   //       -1, Internal error
duke@435:   int  copy_cpool_bytes(int cpool_size,
duke@435:                         SymbolHashMap* tbl,
duke@435:                         unsigned char *bytes);
duke@435: };
duke@435: 
duke@435: class SymbolHashMapEntry : public CHeapObj {
duke@435:  private:
duke@435:   unsigned int        _hash;   // 32-bit hash for item
duke@435:   SymbolHashMapEntry* _next;   // Next element in the linked list for this bucket
duke@435:   symbolOop           _symbol; // 1-st part of the mapping: symbol => value
duke@435:   u2                  _value;  // 2-nd part of the mapping: symbol => value
duke@435: 
duke@435:  public:
duke@435:   unsigned   int hash() const             { return _hash;   }
duke@435:   void       set_hash(unsigned int hash)  { _hash = hash;   }
duke@435: 
duke@435:   SymbolHashMapEntry* next() const        { return _next;   }
duke@435:   void set_next(SymbolHashMapEntry* next) { _next = next;   }
duke@435: 
duke@435:   symbolOop  symbol() const               { return _symbol; }
duke@435:   void       set_symbol(symbolOop sym)    { _symbol = sym;  }
duke@435: 
duke@435:   u2         value() const                {  return _value; }
duke@435:   void       set_value(u2 value)          { _value = value; }
duke@435: 
duke@435:   SymbolHashMapEntry(unsigned int hash, symbolOop symbol, u2 value)
duke@435:     : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {}
duke@435: 
duke@435: }; // End SymbolHashMapEntry class
duke@435: 
duke@435: 
duke@435: class SymbolHashMapBucket : public CHeapObj {
duke@435: 
duke@435: private:
duke@435:   SymbolHashMapEntry*    _entry;
duke@435: 
duke@435: public:
duke@435:   SymbolHashMapEntry* entry() const         {  return _entry; }
duke@435:   void set_entry(SymbolHashMapEntry* entry) { _entry = entry; }
duke@435:   void clear()                              { _entry = NULL;  }
duke@435: 
duke@435: }; // End SymbolHashMapBucket class
duke@435: 
duke@435: 
duke@435: class SymbolHashMap: public CHeapObj {
duke@435: 
duke@435:  private:
duke@435:   // Default number of entries in the table
duke@435:   enum SymbolHashMap_Constants {
duke@435:     _Def_HashMap_Size = 256
duke@435:   };
duke@435: 
duke@435:   int                   _table_size;
duke@435:   SymbolHashMapBucket*  _buckets;
duke@435: 
duke@435:   void initialize_table(int table_size) {
duke@435:     _table_size = table_size;
duke@435:     _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size);
duke@435:     for (int index = 0; index < table_size; index++) {
duke@435:       _buckets[index].clear();
duke@435:     }
duke@435:   }
duke@435: 
duke@435:  public:
duke@435: 
duke@435:   int table_size() const        { return _table_size; }
duke@435: 
duke@435:   SymbolHashMap()               { initialize_table(_Def_HashMap_Size); }
duke@435:   SymbolHashMap(int table_size) { initialize_table(table_size); }
duke@435: 
duke@435:   // hash P(31) from Kernighan & Ritchie
duke@435:   static unsigned int compute_hash(const char* str, int len) {
duke@435:     unsigned int hash = 0;
duke@435:     while (len-- > 0) {
duke@435:       hash = 31*hash + (unsigned) *str;
duke@435:       str++;
duke@435:     }
duke@435:     return hash;
duke@435:   }
duke@435: 
duke@435:   SymbolHashMapEntry* bucket(int i) {
duke@435:     return _buckets[i].entry();
duke@435:   }
duke@435: 
duke@435:   void add_entry(symbolOop sym, u2 value);
duke@435:   SymbolHashMapEntry* find_entry(symbolOop sym);
duke@435: 
duke@435:   u2 symbol_to_value(symbolOop sym) {
duke@435:     SymbolHashMapEntry *entry = find_entry(sym);
duke@435:     return (entry == NULL) ? 0 : entry->value();
duke@435:   }
duke@435: 
duke@435:   ~SymbolHashMap() {
duke@435:     SymbolHashMapEntry* next;
duke@435:     for (int i = 0; i < _table_size; i++) {
duke@435:       for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) {
duke@435:         next = cur->next();
duke@435:         delete(cur);
duke@435:       }
duke@435:     }
duke@435:     delete _buckets;
duke@435:   }
duke@435: }; // End SymbolHashMap class