iposva@google.com
7f843b0fc9
old->new references during Scavenge. Review URL: https://chromiumcodereview.appspot.com//10797021 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@9791 260f80e4-7a28-3924-810f-c04153c831b5
104 lines
2.3 KiB
C++
104 lines
2.3 KiB
C++
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#ifndef VM_HASH_SET_H_
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#define VM_HASH_SET_H_
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#include "vm/allocation.h"
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#include "platform/utils.h"
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namespace dart {
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class HashSet {
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public:
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HashSet(intptr_t size, intptr_t fill_ratio)
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: keys_(new uword[size]),
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size_mask_(size - 1),
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growth_limit_((size * fill_ratio) / 100),
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count_(0),
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fill_ratio_(fill_ratio) {
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ASSERT(Utils::IsPowerOfTwo(size));
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ASSERT(fill_ratio < 100);
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memset(keys_, 0, size * sizeof(*keys_));
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}
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~HashSet() {
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delete[] keys_;
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}
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intptr_t Size() const {
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return size_mask_ + 1;
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}
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intptr_t Count() const {
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return count_;
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}
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uword At(intptr_t i) const {
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ASSERT(i >= 0);
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ASSERT(i < Size());
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return keys_[i];
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}
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// Returns false if the caller should stop adding entries to this HashSet.
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bool Add(uword value) {
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ASSERT(value != 0);
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ASSERT(count_ < growth_limit_);
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intptr_t hash = Hash(value);
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while (true) {
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if (keys_[hash] == value) {
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return true;
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} else if (SlotIsEmpty(hash)) {
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keys_[hash] = value;
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count_++;
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return (count_ < growth_limit_);
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}
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hash = (hash + 1) & size_mask_;
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// Ensure that we do not end up looping forever.
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ASSERT(hash != Hash(value));
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}
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UNREACHABLE();
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}
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bool Contains(uword value) const {
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if (value == 0) {
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return false;
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}
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intptr_t hash = Hash(value);
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while (true) {
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if (keys_[hash] == value) {
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return true;
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} else if (SlotIsEmpty(hash)) {
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return false;
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}
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hash = (hash + 1) & size_mask_;
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// Ensure that we do not end up looping forever.
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ASSERT(hash != Hash(value));
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}
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UNREACHABLE();
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}
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private:
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intptr_t Hash(uword value) const {
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return value & size_mask_;
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}
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// Returns true if the given slot contains a value.
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bool SlotIsEmpty(intptr_t index) const {
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return keys_[index] == 0;
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}
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uword* keys_;
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intptr_t size_mask_;
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intptr_t growth_limit_;
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intptr_t count_;
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intptr_t fill_ratio_;
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DISALLOW_IMPLICIT_CONSTRUCTORS(HashSet);
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};
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} // namespace dart
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#endif // VM_HASH_SET_H_
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