// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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
//
//   http://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 <algorithm>
#include <cstring>
#include <memory>

#include <gtest/gtest.h>
#include <time.h>

#include "util/faststring.h"
#include "util/random.h"

namespace doris {
class FaststringTest : public ::testing::Test {};

void RandomString(void* dest, size_t n, doris::Random* rng) {
  size_t i = 0;
  uint32_t random = rng->Next();
  char* cdest = static_cast<char*>(dest);
  static const size_t sz = sizeof(random);
  if (n >= sz) {
    for (i = 0; i <= n - sz; i += sz) {
      memcpy(&cdest[i], &random, sizeof(random));
      random = rng->Next();
    }
  }
  memcpy(cdest + i, &random, n - i);
}

TEST_F(FaststringTest, TestShrinkToFit_Empty) {
  faststring s;
  s.shrink_to_fit();
  ASSERT_EQ(faststring::kInitialCapacity, s.capacity());
}

// Test that, if the string contents is shorter than the initial capacity
// of the faststring, shrink_to_fit() leaves the string in the built-in
// array.
TEST_F(FaststringTest, TestShrinkToFit_SmallerThanInitialCapacity) {
  faststring s;
  s.append("hello");
  s.shrink_to_fit();
  ASSERT_EQ(faststring::kInitialCapacity, s.capacity());
}

TEST_F(FaststringTest, TestShrinkToFit_Random) {
  doris::Random r(time(nullptr));
  int kMaxSize = faststring::kInitialCapacity * 2;
  std::unique_ptr<char[]> random_bytes(new char[kMaxSize]);
  RandomString(random_bytes.get(), kMaxSize, &r);

  faststring s;
  for (int i = 0; i < 100; i++) {
    int new_size = r.Uniform(kMaxSize);
    s.resize(new_size);
    memcpy(s.data(), random_bytes.get(), new_size);
    s.shrink_to_fit();
    ASSERT_EQ(0, memcmp(s.data(), random_bytes.get(), new_size));
    ASSERT_EQ(std::max<int>(faststring::kInitialCapacity, new_size), s.capacity());
  }
}

} // namespace doris

int main(int argc, char** argv) {
    testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}