The Android Open Source Project | dd7bc33 | 2009-03-03 19:32:55 -0800 | [diff] [blame] | 1 | /* |
Mathias Agopian | 9857d99 | 2013-04-01 15:17:55 -0700 | [diff] [blame] | 2 | * Copyright 2005 The Android Open Source Project |
The Android Open Source Project | dd7bc33 | 2009-03-03 19:32:55 -0800 | [diff] [blame] | 3 | * |
Mathias Agopian | 9857d99 | 2013-04-01 15:17:55 -0700 | [diff] [blame] | 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
The Android Open Source Project | dd7bc33 | 2009-03-03 19:32:55 -0800 | [diff] [blame] | 7 | * |
Mathias Agopian | 9857d99 | 2013-04-01 15:17:55 -0700 | [diff] [blame] | 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
The Android Open Source Project | dd7bc33 | 2009-03-03 19:32:55 -0800 | [diff] [blame] | 15 | */ |
| 16 | |
| 17 | #include <stdlib.h> |
| 18 | #include <string.h> |
| 19 | |
| 20 | #include <cutils/atomic.h> |
| 21 | |
Mathias Agopian | 9857d99 | 2013-04-01 15:17:55 -0700 | [diff] [blame] | 22 | #include "SharedBuffer.h" |
The Android Open Source Project | dd7bc33 | 2009-03-03 19:32:55 -0800 | [diff] [blame] | 23 | |
| 24 | // --------------------------------------------------------------------------- |
| 25 | |
| 26 | namespace android { |
Mathias Agopian | 9857d99 | 2013-04-01 15:17:55 -0700 | [diff] [blame] | 27 | namespace tinyutils { |
The Android Open Source Project | dd7bc33 | 2009-03-03 19:32:55 -0800 | [diff] [blame] | 28 | |
| 29 | SharedBuffer* SharedBuffer::alloc(size_t size) |
| 30 | { |
| 31 | SharedBuffer* sb = static_cast<SharedBuffer *>(malloc(sizeof(SharedBuffer) + size)); |
| 32 | if (sb) { |
| 33 | sb->mRefs = 1; |
| 34 | sb->mSize = size; |
| 35 | } |
| 36 | return sb; |
| 37 | } |
| 38 | |
| 39 | |
| 40 | ssize_t SharedBuffer::dealloc(const SharedBuffer* released) |
| 41 | { |
| 42 | if (released->mRefs != 0) return -1; // XXX: invalid operation |
| 43 | free(const_cast<SharedBuffer*>(released)); |
| 44 | return 0; |
| 45 | } |
| 46 | |
| 47 | SharedBuffer* SharedBuffer::edit() const |
| 48 | { |
| 49 | if (onlyOwner()) { |
| 50 | return const_cast<SharedBuffer*>(this); |
| 51 | } |
| 52 | SharedBuffer* sb = alloc(mSize); |
| 53 | if (sb) { |
| 54 | memcpy(sb->data(), data(), size()); |
| 55 | release(); |
| 56 | } |
| 57 | return sb; |
| 58 | } |
| 59 | |
| 60 | SharedBuffer* SharedBuffer::editResize(size_t newSize) const |
| 61 | { |
| 62 | if (onlyOwner()) { |
| 63 | SharedBuffer* buf = const_cast<SharedBuffer*>(this); |
| 64 | if (buf->mSize == newSize) return buf; |
| 65 | buf = (SharedBuffer*)realloc(buf, sizeof(SharedBuffer) + newSize); |
| 66 | if (buf != NULL) { |
| 67 | buf->mSize = newSize; |
| 68 | return buf; |
| 69 | } |
| 70 | } |
| 71 | SharedBuffer* sb = alloc(newSize); |
| 72 | if (sb) { |
| 73 | const size_t mySize = mSize; |
| 74 | memcpy(sb->data(), data(), newSize < mySize ? newSize : mySize); |
| 75 | release(); |
| 76 | } |
| 77 | return sb; |
| 78 | } |
| 79 | |
| 80 | SharedBuffer* SharedBuffer::attemptEdit() const |
| 81 | { |
| 82 | if (onlyOwner()) { |
| 83 | return const_cast<SharedBuffer*>(this); |
| 84 | } |
| 85 | return 0; |
| 86 | } |
| 87 | |
| 88 | SharedBuffer* SharedBuffer::reset(size_t new_size) const |
| 89 | { |
| 90 | // cheap-o-reset. |
| 91 | SharedBuffer* sb = alloc(new_size); |
| 92 | if (sb) { |
| 93 | release(); |
| 94 | } |
| 95 | return sb; |
| 96 | } |
| 97 | |
| 98 | void SharedBuffer::acquire() const { |
| 99 | android_atomic_inc(&mRefs); |
| 100 | } |
| 101 | |
| 102 | int32_t SharedBuffer::release(uint32_t flags) const |
| 103 | { |
| 104 | int32_t prev = 1; |
| 105 | if (onlyOwner() || ((prev = android_atomic_dec(&mRefs)) == 1)) { |
| 106 | mRefs = 0; |
| 107 | if ((flags & eKeepStorage) == 0) { |
| 108 | free(const_cast<SharedBuffer*>(this)); |
| 109 | } |
| 110 | } |
| 111 | return prev; |
| 112 | } |
| 113 | |
Mathias Agopian | 9857d99 | 2013-04-01 15:17:55 -0700 | [diff] [blame] | 114 | } // namespace tinyutils |
| 115 | } // namespace android |