test_harness.h

// 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.
#pragma once
 
#include <cstddef>
#include <optional>
#include <variant>
 
#include "pw_allocator/allocator.h"
#include "pw_containers/intrusive_list.h"
#include "pw_containers/vector.h"
#include "pw_random/xor_shift.h"
 
namespace pw::allocator::test {
 
struct AllocationRequest {
  size_t size = 0;
  size_t alignment = 1;
};
 
struct DeallocationRequest {
  size_t index = 0;
};
 
struct ReallocationRequest {
  size_t index = 0;
  size_t new_size = 0;
};
 
using Request =
    std::variant<AllocationRequest, DeallocationRequest, ReallocationRequest>;
 
size_t AlignmentFromLShift(size_t lshift, size_t size);
 
class TestHarness {
 public:
  struct Allocation : public IntrusiveList<Allocation>::Item {
    Layout layout;
 
    explicit Allocation(Layout layout_) : layout(layout_) {}
  };
 
  TestHarness() = default;
  explicit TestHarness(Allocator& allocator) : allocator_(&allocator) {}
  virtual ~TestHarness() = default;
 
  size_t num_allocations() const { return num_allocations_; }
  size_t allocated() const { return allocated_; }
 
  void set_allocator(Allocator* allocator) { allocator_ = allocator; }
  void set_prng_seed(uint64_t seed) { prng_ = random::XorShiftStarRng64(seed); }
  void set_available(size_t available) { available_ = available; }
 
  void GenerateRequests(size_t max_size, size_t num_requests);
 
  void GenerateRequest(size_t max_size);
 
  void HandleRequests(const Vector<Request>& requests);
 
  bool HandleRequest(const Request& request);
 
  void Reset();
 
 private:
  AllocationRequest GenerateAllocationRequest(size_t max_size);
  DeallocationRequest GenerateDeallocationRequest();
  ReallocationRequest GenerateReallocationRequest(size_t max_size);
  size_t GenerateSize(size_t max_size);
 
  virtual void BeforeAllocate(const Layout&) {}
  virtual void AfterAllocate(const void*) {}
  virtual void BeforeReallocate(const Layout&) {}
  virtual void AfterReallocate(const void*) {}
  virtual void BeforeDeallocate(const void*) {}
  virtual void AfterDeallocate() {}
 
  void AddAllocation(void* ptr, Layout layout);
 
  Allocation* RemoveAllocation(size_t index);
 
  Allocator* allocator_ = nullptr;
 
  IntrusiveList<Allocation> allocations_;
 
  size_t num_allocations_ = 0;
 
  size_t allocated_ = 0;
 
  std::optional<size_t> available_;
 
  std::optional<random::XorShiftStarRng64> prng_;
 
  std::optional<size_t> max_size_;
};
 
}  // namespace pw::allocator::test