1 // Copyright 2020 The Pigweed Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4 // use this file except in compliance with the License. You may obtain a copy of
5 // the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12 // License for the specific language governing permissions and limitations under
13 // the License.
14
15 #include "pw_kvs/alignment.h"
16
17 #include "pw_status/try.h"
18
19 namespace pw {
20
Write(std::span<const std::byte> data)21 StatusWithSize AlignedWriter::Write(std::span<const std::byte> data) {
22 while (!data.empty()) {
23 size_t to_copy = std::min(write_size_ - bytes_in_buffer_, data.size());
24
25 std::memcpy(&buffer_[bytes_in_buffer_], data.data(), to_copy);
26 PW_TRY_WITH_SIZE(AddBytesToBuffer(to_copy));
27 data = data.subspan(to_copy);
28 }
29
30 return StatusWithSize(bytes_written_);
31 }
32
Flush()33 StatusWithSize AlignedWriter::Flush() {
34 Status status;
35
36 // If data remains in the buffer, pad it to the alignment size and flush the
37 // remaining data.
38 if (bytes_in_buffer_ != 0u) {
39 const size_t remaining_bytes = AlignUp(bytes_in_buffer_, alignment_bytes_);
40 std::memset(&buffer_[bytes_in_buffer_],
41 int(kPadByte),
42 remaining_bytes - bytes_in_buffer_);
43 status = output_.Write(buffer_, remaining_bytes).status();
44
45 bytes_written_ += remaining_bytes; // Include padding in the total.
46 bytes_in_buffer_ = 0;
47 }
48
49 const StatusWithSize result(status, bytes_written_);
50 bytes_written_ = 0;
51 return result;
52 }
53
Write(Input & input,size_t size)54 StatusWithSize AlignedWriter::Write(Input& input, size_t size) {
55 while (size > 0u) {
56 const size_t to_read = std::min(write_size_ - bytes_in_buffer_, size);
57 StatusWithSize result = input.Read(buffer_ + bytes_in_buffer_, to_read);
58 if (!result.ok()) {
59 return StatusWithSize(result.status(), bytes_written_);
60 }
61 PW_TRY_WITH_SIZE(AddBytesToBuffer(to_read));
62 size -= result.size();
63 }
64
65 return StatusWithSize(bytes_written_);
66 }
67
AddBytesToBuffer(size_t bytes_added)68 StatusWithSize AlignedWriter::AddBytesToBuffer(size_t bytes_added) {
69 bytes_in_buffer_ += bytes_added;
70
71 // If the buffer is full, write it out.
72 if (bytes_in_buffer_ == write_size_) {
73 StatusWithSize result = output_.Write(buffer_, write_size_);
74
75 // Always use write_size_ for the bytes written. If there was an error
76 // assume the space was written or at least disturbed.
77 bytes_written_ += write_size_;
78 bytes_in_buffer_ = 0;
79
80 if (!result.ok()) {
81 return StatusWithSize(result.status(), bytes_written_);
82 }
83 }
84
85 return StatusWithSize(bytes_written_);
86 }
87
88 } // namespace pw
89