1 // Copyright 2021 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 #include "pw_persistent_ram/persistent_buffer.h" 15 16 #include "pw_bytes/span.h" 17 #include "pw_checksum/crc16_ccitt.h" 18 #include "pw_status/status.h" 19 20 namespace pw::persistent_ram { 21 DoWrite(ConstByteSpan data)22Status PersistentBufferWriter::DoWrite(ConstByteSpan data) { 23 if (ConservativeWriteLimit() == 0) { 24 return Status::OutOfRange(); 25 } 26 if (ConservativeWriteLimit() < data.size_bytes()) { 27 return Status::ResourceExhausted(); 28 } 29 if (data.empty()) { 30 return OkStatus(); 31 } 32 33 std::memcpy(buffer_.data() + size_, data.data(), data.size_bytes()); 34 35 // Only checksum newly written data. 36 checksum_ = checksum::Crc16Ccitt::Calculate( 37 ByteSpan(buffer_.data() + size_, data.size_bytes()), checksum_); 38 size_ = size_ + data.size_bytes(); // += on a volatile is deprecated in C++20 39 40 return OkStatus(); 41 } 42 43 } // namespace pw::persistent_ram 44