1 // Copyright 2023 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_bytes/alignment.h" 16 17 #include <cstdint> 18 19 namespace pw { 20 GetAlignedSubspan(ByteSpan bytes,size_t alignment)21ByteSpan GetAlignedSubspan(ByteSpan bytes, size_t alignment) { 22 if (bytes.data() == nullptr) { 23 return ByteSpan(); 24 } 25 auto unaligned_start = reinterpret_cast<uintptr_t>(bytes.data()); 26 auto aligned_start = AlignUp(unaligned_start, alignment); 27 auto unaligned_end = unaligned_start + bytes.size(); 28 auto aligned_end = AlignDown(unaligned_end, alignment); 29 if (aligned_end <= aligned_start) { 30 return ByteSpan(); 31 } 32 return bytes.subspan(aligned_start - unaligned_start, 33 aligned_end - aligned_start); 34 } 35 36 } // namespace pw 37