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 | |
30 | namespace bmalloc { |
31 | |
32 | FreeList::FreeList() |
33 | { |
34 | } |
35 | |
36 | FreeList::~FreeList() |
37 | { |
38 | } |
39 | |
40 | void FreeList::clear() |
41 | { |
42 | *this = FreeList(); |
43 | } |
44 | |
45 | void 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 | |
55 | void 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 | |
64 | bool 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 | |