1 /*
2 * Copyright (C) 2021 The Android Open Source Project
3 *
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
7 *
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.
15 */
16
17 #include <snapuserd/snapuserd_buffer.h>
18
19 #include <android-base/logging.h>
20 #include <snapuserd/snapuserd_kernel.h>
21
22 namespace android {
23 namespace snapshot {
24
Initialize(size_t header_size,size_t size)25 void BufferSink::Initialize(size_t header_size, size_t size) {
26 header_size_ = header_size;
27 buffer_size_ = size + header_size;
28 buffer_offset_ = 0;
29 buffer_ = std::make_unique<uint8_t[]>(buffer_size_);
30 }
31
AcquireBuffer(size_t size,size_t to_write)32 void* BufferSink::AcquireBuffer(size_t size, size_t to_write) {
33 CHECK(to_write <= size);
34
35 void* ptr = GetPayloadBuffer(size);
36 if (!ptr) {
37 return nullptr;
38 }
39 UpdateBufferOffset(to_write);
40 return ptr;
41 }
42
GetPayloadBuffer(size_t size)43 void* BufferSink::GetPayloadBuffer(size_t size) {
44 char* buffer = reinterpret_cast<char*>(GetBufPtr());
45
46 if ((buffer_size_ - buffer_offset_ - header_size_) < size) {
47 return nullptr;
48 }
49 return (char*)(&buffer[0] + header_size_ + buffer_offset_);
50 }
51
GetBuffer(size_t requested,size_t * actual)52 void* BufferSink::GetBuffer(size_t requested, size_t* actual) {
53 void* buf = GetPayloadBuffer(requested);
54 if (!buf) {
55 *actual = 0;
56 return nullptr;
57 }
58 *actual = requested;
59 return buf;
60 }
61
GetHeaderPtr()62 void* BufferSink::GetHeaderPtr() {
63 // If no sufficient space or header not reserved
64 if (!(header_size_ <= buffer_size_) || !header_size_) {
65 return nullptr;
66 }
67 char* buf = reinterpret_cast<char*>(GetBufPtr());
68 return (void*)(&(buf[0]));
69 }
70
GetPayloadBufPtr()71 void* BufferSink::GetPayloadBufPtr() {
72 char* buffer = reinterpret_cast<char*>(GetBufPtr());
73 return &buffer[header_size_];
74 }
75
76 } // namespace snapshot
77 } // namespace android
78