// Copyright 2023 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/bump_allocator.h"

#include "pw_allocator/buffer.h"
#include "pw_bytes/alignment.h"

namespace pw::allocator {

void BumpAllocator::Init(ByteSpan region) {
  Reset();
  remaining_ = region;
}

void* BumpAllocator::DoAllocate(Layout layout) {
  size_t remaining = remaining_.size();
  ByteSpan region = GetAlignedSubspan(remaining_, layout.alignment());
  if (region.size() < layout.size()) {
    return nullptr;
  }
  remaining_ = region.subspan(layout.size());
  allocated_ += remaining - remaining_.size();
  return region.data();
}

void BumpAllocator::DoDeallocate(void*) {}

void BumpAllocator::Reset() {
  if (owned_ != nullptr) {
    owned_->Destroy();
  }
  remaining_ = ByteSpan();
}

}  // namespace pw::allocator