30a0a7de43
This issue was raised by Brett Wilson while reviewing my changelist for readability. Craig Silverstein (one of C++ SG maintainers) confirmed that we should declare one namespace per line. Our way of namespaces closing seems not violating style guides (there is no clear agreement on it), so I left it intact. Review URL: http://codereview.chromium.org/115756 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2038 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
121 lines
4.0 KiB
C++
121 lines
4.0 KiB
C++
// Copyright 2008 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef V8_HASHMAP_H_
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#define V8_HASHMAP_H_
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namespace v8 {
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namespace internal {
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// Allocator defines the memory allocator interface
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// used by HashMap and implements a default allocator.
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class Allocator BASE_EMBEDDED {
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public:
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virtual ~Allocator() {}
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virtual void* New(size_t size) { return Malloced::New(size); }
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virtual void Delete(void* p) { Malloced::Delete(p); }
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};
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class HashMap {
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public:
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static Allocator DefaultAllocator;
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typedef bool (*MatchFun) (void* key1, void* key2);
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// Dummy constructor. This constructor doesn't set up the hash
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// map properly so don't use it unless you have good reason.
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HashMap();
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// initial_capacity is the size of the initial hash map;
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// it must be a power of 2 (and thus must not be 0).
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HashMap(MatchFun match,
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Allocator* allocator = &DefaultAllocator,
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uint32_t initial_capacity = 8);
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~HashMap();
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// HashMap entries are (key, value, hash) triplets.
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// Some clients may not need to use the value slot
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// (e.g. implementers of sets, where the key is the value).
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struct Entry {
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void* key;
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void* value;
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uint32_t hash; // the full hash value for key
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};
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// If an entry with matching key is found, Lookup()
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// returns that entry. If no matching entry is found,
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// but insert is set, a new entry is inserted with
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// corresponding key, key hash, and NULL value.
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// Otherwise, NULL is returned.
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Entry* Lookup(void* key, uint32_t hash, bool insert);
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// Removes the entry with matching key.
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void Remove(void* key, uint32_t hash);
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// Empties the hash map (occupancy() == 0).
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void Clear();
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// The number of (non-empty) entries in the table.
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uint32_t occupancy() const { return occupancy_; }
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// The capacity of the table. The implementation
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// makes sure that occupancy is at most 80% of
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// the table capacity.
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uint32_t capacity() const { return capacity_; }
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// Iteration
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//
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// for (Entry* p = map.Start(); p != NULL; p = map.Next(p)) {
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// ...
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// }
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//
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// If entries are inserted during iteration, the effect of
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// calling Next() is undefined.
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Entry* Start() const;
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Entry* Next(Entry* p) const;
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private:
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Allocator* allocator_;
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MatchFun match_;
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Entry* map_;
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uint32_t capacity_;
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uint32_t occupancy_;
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Entry* map_end() const { return map_ + capacity_; }
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Entry* Probe(void* key, uint32_t hash);
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void Initialize(uint32_t capacity);
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void Resize();
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};
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} } // namespace v8::internal
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#endif // V8_HASHMAP_H_
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