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//===-- Implementation for freelist ---------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "freelist.h"
namespace LIBC_NAMESPACE_DECL {
void FreeList::push(Node *node) {
if (begin_) {
LIBC_ASSERT(Block::from_usable_space(node)->outer_size() ==
begin_->block()->outer_size() &&
"freelist entries must have the same size");
// Since the list is circular, insert the node immediately before begin_.
node->prev = begin_->prev;
node->next = begin_;
begin_->prev->next = node;
begin_->prev = node;
} else {
begin_ = node->prev = node->next = node;
}
}
void FreeList::remove(Node *node) {
LIBC_ASSERT(begin_ && "cannot remove from empty list");
if (node == node->next) {
LIBC_ASSERT(node == begin_ &&
"a self-referential node must be the only element");
begin_ = nullptr;
} else {
node->prev->next = node->next;
node->next->prev = node->prev;
if (begin_ == node)
begin_ = node->next;
}
}
} // namespace LIBC_NAMESPACE_DECL
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