| 1 | //===-- Implementation for freelist ---------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "freelist.h" |
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| 10 | |
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| 11 | namespace LIBC_NAMESPACE_DECL { |
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| 12 | |
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| 13 | void FreeList::push(Node *node) { |
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| 14 | if (begin_) { |
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| 15 | LIBC_ASSERT(Block::from_usable_space(node)->outer_size() == |
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| 16 | begin_->block()->outer_size() && |
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| 17 | "freelist entries must have the same size" ); |
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| 18 | // Since the list is circular, insert the node immediately before begin_. |
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| 19 | node->prev = begin_->prev; |
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| 20 | node->next = begin_; |
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| 21 | begin_->prev->next = node; |
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| 22 | begin_->prev = node; |
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| 23 | } else { |
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| 24 | begin_ = node->prev = node->next = node; |
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| 25 | } |
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| 26 | } |
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| 27 | |
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| 28 | void FreeList::remove(Node *node) { |
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| 29 | LIBC_ASSERT(begin_ && "cannot remove from empty list" ); |
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| 30 | if (node == node->next) { |
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| 31 | LIBC_ASSERT(node == begin_ && |
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| 32 | "a self-referential node must be the only element" ); |
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| 33 | begin_ = nullptr; |
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| 34 | } else { |
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| 35 | node->prev->next = node->next; |
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| 36 | node->next->prev = node->prev; |
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| 37 | if (begin_ == node) |
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| 38 | begin_ = node->next; |
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| 39 | } |
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| 40 | } |
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| 41 | |
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| 42 | } // namespace LIBC_NAMESPACE_DECL |
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| 43 | |
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