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// Copyright 2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_HASHMAP_H_
#define V8_HASHMAP_H_
namespace v8 {
namespace internal {
// Allocator defines the memory allocator interface
// used by HashMap and implements a default allocator.
class Allocator BASE_EMBEDDED {
public:
virtual ~Allocator() {}
virtual void* New(size_t size) { return Malloced::New(size); }
virtual void Delete(void* p) { Malloced::Delete(p); }
};
class HashMap {
public:
static Allocator DefaultAllocator;
typedef bool (*MatchFun) (void* key1, void* key2);
// Dummy constructor. This constructor doesn't set up the hash
// map properly so don't use it unless you have good reason.
HashMap();
// initial_capacity is the size of the initial hash map;
// it must be a power of 2 (and thus must not be 0).
HashMap(MatchFun match,
Allocator* allocator = &DefaultAllocator,
uint32_t initial_capacity = 8);
~HashMap();
// HashMap entries are (key, value, hash) triplets.
// Some clients may not need to use the value slot
// (e.g. implementers of sets, where the key is the value).
struct Entry {
void* key;
void* value;
uint32_t hash; // the full hash value for key
};
// If an entry with matching key is found, Lookup()
// returns that entry. If no matching entry is found,
// but insert is set, a new entry is inserted with
// corresponding key, key hash, and NULL value.
// Otherwise, NULL is returned.
Entry* Lookup(void* key, uint32_t hash, bool insert);
// Removes the entry with matching key.
void Remove(void* key, uint32_t hash);
// Empties the hash map (occupancy() == 0).
void Clear();
// The number of (non-empty) entries in the table.
uint32_t occupancy() const { return occupancy_; }
// The capacity of the table. The implementation
// makes sure that occupancy is at most 80% of
// the table capacity.
uint32_t capacity() const { return capacity_; }
// Iteration
//
// for (Entry* p = map.Start(); p != NULL; p = map.Next(p)) {
// ...
// }
//
// If entries are inserted during iteration, the effect of
// calling Next() is undefined.
Entry* Start() const;
Entry* Next(Entry* p) const;
private:
Allocator* allocator_;
MatchFun match_;
Entry* map_;
uint32_t capacity_;
uint32_t occupancy_;
Entry* map_end() const { return map_ + capacity_; }
Entry* Probe(void* key, uint32_t hash);
void Initialize(uint32_t capacity);
void Resize();
};
} } // namespace v8::internal
#endif // V8_HASHMAP_H_
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