1/*
2 * Copyright (C) 2016-2017 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "FreeList.h"
27
28#include "FreeListInlines.h"
29
30namespace bmalloc {
31
32FreeList::FreeList()
33{
34}
35
36FreeList::~FreeList()
37{
38}
39
40void FreeList::clear()
41{
42 *this = FreeList();
43}
44
45void FreeList::initializeList(FreeCell* head, uintptr_t secret, unsigned bytes)
46{
47 // It's *slightly* more optimal to use a scrambled head. It saves a register on the fast path.
48 m_scrambledHead = FreeCell::scramble(head, secret);
49 m_secret = secret;
50 m_payloadEnd = nullptr;
51 m_remaining = 0;
52 m_originalSize = bytes;
53}
54
55void FreeList::initializeBump(char* payloadEnd, unsigned remaining)
56{
57 m_scrambledHead = 0;
58 m_secret = 0;
59 m_payloadEnd = payloadEnd;
60 m_remaining = remaining;
61 m_originalSize = remaining;
62}
63
64bool FreeList::contains(void* target) const
65{
66 if (m_remaining) {
67 const void* start = (m_payloadEnd - m_remaining);
68 const void* end = m_payloadEnd;
69 return (start <= target) && (target < end);
70 }
71
72 FreeCell* candidate = head();
73 while (candidate) {
74 if (static_cast<void*>(candidate) == target)
75 return true;
76 candidate = candidate->next(m_secret);
77 }
78
79 return false;
80}
81
82} // namespace JSC
83
84