| // Copyright 2024 The Pigweed Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| // use this file except in compliance with the License. You may obtain a copy of |
| // the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| // License for the specific language governing permissions and limitations under |
| // the License. |
| |
| #include "pw_allocator/buffer.h" |
| |
| #include "pw_assert/check.h" |
| #include "pw_bytes/alignment.h" |
| |
| namespace pw::allocator { |
| |
| Result<ByteSpan> GetAlignedSubspan(ByteSpan bytes, size_t alignment) { |
| if (bytes.data() == nullptr) { |
| return Status::ResourceExhausted(); |
| } |
| auto unaligned_start = reinterpret_cast<uintptr_t>(bytes.data()); |
| auto aligned_start = AlignUp(unaligned_start, alignment); |
| auto unaligned_end = unaligned_start + bytes.size(); |
| auto aligned_end = AlignDown(unaligned_end, alignment); |
| if (aligned_end <= aligned_start) { |
| return Status::ResourceExhausted(); |
| } |
| return bytes.subspan(aligned_start - unaligned_start, |
| aligned_end - aligned_start); |
| } |
| |
| bool IsWithin(const void* ptr, size_t size, ConstByteSpan outer) { |
| auto outer_start = reinterpret_cast<uintptr_t>(outer.data()); |
| auto start = reinterpret_cast<uintptr_t>(ptr); |
| uintptr_t end; |
| PW_CHECK_ADD(start, size, &end); |
| return outer_start <= start && end <= (outer_start + outer.size()); |
| } |
| |
| } // namespace pw::allocator |