src/tests/benchmarks/fidl/reference/encode_benchmark_util.h

// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef SRC_TESTS_BENCHMARKS_FIDL_REFERENCE_ENCODE_BENCHMARK_UTIL_H_
#define SRC_TESTS_BENCHMARKS_FIDL_REFERENCE_ENCODE_BENCHMARK_UTIL_H_

#include <lib/fidl/internal.h>
#include <zircon/fidl.h>

#include <cstdint>
#include <iostream>

#include <perftest/perftest.h>

namespace encode_benchmark_util {

template <typename BuilderFunc, typename EncodeFunc>
bool EncodeBenchmark(perftest::RepeatState* state, BuilderFunc builder, EncodeFunc encode) {
  using FidlType = std::invoke_result_t<BuilderFunc>;
  static_assert(fidl::IsFidlType<FidlType>::value, "FIDL type required");

  state->DeclareStep("Setup/WallTime");
  state->DeclareStep("Encode/WallTime");
  state->DeclareStep("Teardown/WallTime");

  while (state->KeepRunning()) {
    fidl::aligned<FidlType> aligned_value = builder();

    state->NextStep();  // End: Setup. Begin: Encode.

    const char* error;
    if (!encode(&aligned_value.value, &error, [](const uint8_t*, size_t) {})) {
      std::cout << "error in encode benchmark: " << error << std::endl;
      return false;
    }

    state->NextStep();  // End: Encode. Begin: Teardown.
  }

  // Encode the input with fidl::Encode and compare againt encode().
  fidl::aligned<FidlType> aligned_value = builder();
  ::fidl::internal::LinearizeBuffer<FidlType> buf;
  auto encode_result = ::fidl::LinearizeAndEncode<FidlType>(&aligned_value.value, buf.buffer());
  ZX_ASSERT(encode_result.status == ZX_OK && encode_result.error == nullptr);
  const fidl::BytePart& expected_bytes = encode_result.message.bytes();

  aligned_value = builder();
  std::vector<uint8_t> reference_bytes;
  const char* error;
  if (!encode(&aligned_value.value, &error, [&reference_bytes](const uint8_t* bytes, size_t size) {
        reference_bytes.resize(size);
        memcpy(reference_bytes.data(), bytes, size);
      })) {
    std::cout << "encode failed with error: " << error << std::endl;
    return false;
  }

  if (expected_bytes.actual() != reference_bytes.size()) {
    std::cout << "output size mismatch - encoded reference size was " << reference_bytes.size()
              << " but expected encode result size was" << expected_bytes.actual() << std::endl;
    return false;
  }
  bool success = true;
  for (size_t i = 0; i < expected_bytes.size(); i++) {
    if (expected_bytes.data()[i] != reference_bytes.data()[i]) {
      std::cout << "At offset " << i << " reference got 0x" << std::setw(2) << std::setfill('0')
                << std::hex << int(reference_bytes.data()[i]) << " but fidl::Decode got 0x"
                << int(expected_bytes.data()[i]) << std::dec << std::endl;
      success = false;
    }
  }
  return success;
}

}  // namespace encode_benchmark_util

#endif  // SRC_TESTS_BENCHMARKS_FIDL_REFERENCE_ENCODE_BENCHMARK_UTIL_H_