/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * 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
 *
 *      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 <memory>
#include <random>

#include "allocator.h"
#include "base/stl_util.h"
#include "bit_vector-inl.h"
#include "gtest/gtest.h"
#include "transform_iterator.h"

namespace art {

TEST(BitVector, Test) {
  const size_t kBits = 32;

  BitVector bv(kBits, false, Allocator::GetCallocAllocator());
  EXPECT_EQ(1U, bv.GetStorageSize());
  EXPECT_EQ(sizeof(uint32_t), bv.GetSizeOf());
  EXPECT_FALSE(bv.IsExpandable());

  EXPECT_EQ(0U, bv.NumSetBits());
  EXPECT_EQ(0U, bv.NumSetBits(1));
  EXPECT_EQ(0U, bv.NumSetBits(kBits));
  for (size_t i = 0; i < kBits; i++) {
    EXPECT_FALSE(bv.IsBitSet(i));
  }
  EXPECT_EQ(0U, bv.GetRawStorageWord(0));
  EXPECT_EQ(0U, *bv.GetRawStorage());

  EXPECT_TRUE(bv.Indexes().begin().Done());
  EXPECT_TRUE(bv.Indexes().begin() == bv.Indexes().end());

  bv.SetBit(0);
  bv.SetBit(kBits - 1);
  EXPECT_EQ(2U, bv.NumSetBits());
  EXPECT_EQ(1U, bv.NumSetBits(1));
  EXPECT_EQ(2U, bv.NumSetBits(kBits));
  EXPECT_TRUE(bv.IsBitSet(0));
  for (size_t i = 1; i < kBits - 1; i++) {
    EXPECT_FALSE(bv.IsBitSet(i));
  }
  EXPECT_TRUE(bv.IsBitSet(kBits - 1));
  EXPECT_EQ(0x80000001U, bv.GetRawStorageWord(0));
  EXPECT_EQ(0x80000001U, *bv.GetRawStorage());

  BitVector::IndexIterator iterator = bv.Indexes().begin();
  EXPECT_TRUE(iterator != bv.Indexes().end());
  EXPECT_EQ(0u, *iterator);
  ++iterator;
  EXPECT_TRUE(iterator != bv.Indexes().end());
  EXPECT_EQ(kBits - 1u, *iterator);
  ++iterator;
  EXPECT_TRUE(iterator == bv.Indexes().end());
}

struct MessyAllocator : public Allocator {
 public:
  MessyAllocator() : malloc_(Allocator::GetCallocAllocator()) {}
  ~MessyAllocator() {}

  void* Alloc(size_t s) override {
    void* res = malloc_->Alloc(s);
    memset(res, 0xfe, s);
    return res;
  }

  void Free(void* v) override {
    malloc_->Free(v);
  }

 private:
  Allocator* malloc_;
};

TEST(BitVector, MessyAllocator) {
  MessyAllocator alloc;
  BitVector bv(32, false, &alloc);
  bv.ClearAllBits();
  EXPECT_EQ(bv.NumSetBits(), 0u);
  EXPECT_EQ(bv.GetHighestBitSet(), -1);
}

TEST(BitVector, NoopAllocator) {
  const uint32_t kWords = 2;

  uint32_t bits[kWords];
  memset(bits, 0, sizeof(bits));

  BitVector bv(false, Allocator::GetNoopAllocator(), kWords, bits);
  EXPECT_EQ(kWords, bv.GetStorageSize());
  EXPECT_EQ(kWords * sizeof(uint32_t), bv.GetSizeOf());
  EXPECT_EQ(bits, bv.GetRawStorage());
  EXPECT_EQ(0U, bv.NumSetBits());

  bv.SetBit(8);
  EXPECT_EQ(1U, bv.NumSetBits());
  EXPECT_EQ(0x00000100U, bv.GetRawStorageWord(0));
  EXPECT_EQ(0x00000000U, bv.GetRawStorageWord(1));
  EXPECT_EQ(1U, bv.NumSetBits());

  bv.SetBit(16);
  EXPECT_EQ(2U, bv.NumSetBits());
  EXPECT_EQ(0x00010100U, bv.GetRawStorageWord(0));
  EXPECT_EQ(0x00000000U, bv.GetRawStorageWord(1));
  EXPECT_EQ(2U, bv.NumSetBits());

  bv.SetBit(32);
  EXPECT_EQ(3U, bv.NumSetBits());
  EXPECT_EQ(0x00010100U, bv.GetRawStorageWord(0));
  EXPECT_EQ(0x00000001U, bv.GetRawStorageWord(1));
  EXPECT_EQ(3U, bv.NumSetBits());

  bv.SetBit(48);
  EXPECT_EQ(4U, bv.NumSetBits());
  EXPECT_EQ(0x00010100U, bv.GetRawStorageWord(0));
  EXPECT_EQ(0x00010001U, bv.GetRawStorageWord(1));
  EXPECT_EQ(4U, bv.NumSetBits());

  EXPECT_EQ(0U, bv.NumSetBits(1));

  EXPECT_EQ(0U, bv.NumSetBits(8));
  EXPECT_EQ(1U, bv.NumSetBits(9));
  EXPECT_EQ(1U, bv.NumSetBits(10));

  EXPECT_EQ(1U, bv.NumSetBits(16));
  EXPECT_EQ(2U, bv.NumSetBits(17));
  EXPECT_EQ(2U, bv.NumSetBits(18));

  EXPECT_EQ(2U, bv.NumSetBits(32));
  EXPECT_EQ(3U, bv.NumSetBits(33));
  EXPECT_EQ(3U, bv.NumSetBits(34));

  EXPECT_EQ(3U, bv.NumSetBits(48));
  EXPECT_EQ(4U, bv.NumSetBits(49));
  EXPECT_EQ(4U, bv.NumSetBits(50));

  EXPECT_EQ(4U, bv.NumSetBits(64));
}

TEST(BitVector, SetInitialBits) {
  const uint32_t kWords = 2;

  uint32_t bits[kWords];
  memset(bits, 0, sizeof(bits));

  BitVector bv(false, Allocator::GetNoopAllocator(), kWords, bits);
  bv.SetInitialBits(0u);
  EXPECT_EQ(0u, bv.NumSetBits());
  bv.SetInitialBits(1u);
  EXPECT_EQ(1u, bv.NumSetBits());
  bv.SetInitialBits(32u);
  EXPECT_EQ(32u, bv.NumSetBits());
  bv.SetInitialBits(63u);
  EXPECT_EQ(63u, bv.NumSetBits());
  bv.SetInitialBits(64u);
  EXPECT_EQ(64u, bv.NumSetBits());
}

TEST(BitVector, UnionIfNotIn) {
  {
    BitVector first(2, true, Allocator::GetCallocAllocator());
    BitVector second(5, true, Allocator::GetCallocAllocator());
    BitVector third(5, true, Allocator::GetCallocAllocator());

    second.SetBit(64);
    third.SetBit(64);
    bool changed = first.UnionIfNotIn(&second, &third);
    EXPECT_EQ(0u, first.NumSetBits());
    EXPECT_FALSE(changed);
  }

  {
    BitVector first(2, true, Allocator::GetCallocAllocator());
    BitVector second(5, true, Allocator::GetCallocAllocator());
    BitVector third(5, true, Allocator::GetCallocAllocator());

    second.SetBit(64);
    bool changed = first.UnionIfNotIn(&second, &third);
    EXPECT_EQ(1u, first.NumSetBits());
    EXPECT_TRUE(changed);
    EXPECT_TRUE(first.IsBitSet(64));
  }
}

TEST(BitVector, Subset) {
  {
    BitVector first(2, true, Allocator::GetCallocAllocator());
    BitVector second(5, true, Allocator::GetCallocAllocator());

    EXPECT_TRUE(first.IsSubsetOf(&second));
    second.SetBit(4);
    EXPECT_TRUE(first.IsSubsetOf(&second));
  }

  {
    BitVector first(5, true, Allocator::GetCallocAllocator());
    BitVector second(5, true, Allocator::GetCallocAllocator());

    first.SetBit(5);
    EXPECT_FALSE(first.IsSubsetOf(&second));
    second.SetBit(4);
    EXPECT_FALSE(first.IsSubsetOf(&second));
  }

  {
    BitVector first(5, true, Allocator::GetCallocAllocator());
    BitVector second(5, true, Allocator::GetCallocAllocator());

    first.SetBit(16);
    first.SetBit(32);
    first.SetBit(48);
    second.SetBit(16);
    second.SetBit(32);
    second.SetBit(48);

    EXPECT_TRUE(first.IsSubsetOf(&second));
    second.SetBit(8);
    EXPECT_TRUE(first.IsSubsetOf(&second));
    second.SetBit(40);
    EXPECT_TRUE(first.IsSubsetOf(&second));
    second.SetBit(52);
    EXPECT_TRUE(first.IsSubsetOf(&second));

    first.SetBit(9);
    EXPECT_FALSE(first.IsSubsetOf(&second));
  }
}

TEST(BitVector, CopyTo) {
  {
    // Test copying an empty BitVector. Padding should fill `buf` with zeroes.
    BitVector bv(0, true, Allocator::GetCallocAllocator());
    uint32_t buf;

    bv.CopyTo(&buf, sizeof(buf));
    EXPECT_EQ(0u, bv.GetSizeOf());
    EXPECT_EQ(0u, buf);
  }

  {
    // Test copying when `bv.storage_` and `buf` are of equal lengths.
    BitVector bv(0, true, Allocator::GetCallocAllocator());
    uint32_t buf;

    bv.SetBit(0);
    bv.SetBit(17);
    bv.SetBit(26);
    EXPECT_EQ(sizeof(buf), bv.GetSizeOf());

    bv.CopyTo(&buf, sizeof(buf));
    EXPECT_EQ(0x04020001u, buf);
  }

  {
    // Test copying when the `bv.storage_` is longer than `buf`. As long as
    // `buf` is long enough to hold all set bits, copying should succeed.
    BitVector bv(0, true, Allocator::GetCallocAllocator());
    uint8_t buf[5];

    bv.SetBit(18);
    bv.SetBit(39);
    EXPECT_LT(sizeof(buf), bv.GetSizeOf());

    bv.CopyTo(buf, sizeof(buf));
    EXPECT_EQ(0x00u, buf[0]);
    EXPECT_EQ(0x00u, buf[1]);
    EXPECT_EQ(0x04u, buf[2]);
    EXPECT_EQ(0x00u, buf[3]);
    EXPECT_EQ(0x80u, buf[4]);
  }

  {
    // Test zero padding when `bv.storage_` is shorter than `buf`.
    BitVector bv(0, true, Allocator::GetCallocAllocator());
    uint32_t buf[2];

    bv.SetBit(18);
    bv.SetBit(31);
    EXPECT_GT(sizeof(buf), bv.GetSizeOf());

    bv.CopyTo(buf, sizeof(buf));
    EXPECT_EQ(0x80040000U, buf[0]);
    EXPECT_EQ(0x00000000U, buf[1]);
  }
}

TEST(BitVector, TransformIterator) {
  BitVector bv(16, false, Allocator::GetCallocAllocator());
  bv.SetBit(4);
  bv.SetBit(8);

  auto indexs = bv.Indexes();
  for (int32_t negative :
       MakeTransformRange(indexs, [](uint32_t idx) { return -1 * static_cast<int32_t>(idx); })) {
    EXPECT_TRUE(negative == -4 || negative == -8);
  }
}

class SingleAllocator : public Allocator {
 public:
  SingleAllocator() : alloc_count_(0), free_count_(0) {}
  ~SingleAllocator() {
    EXPECT_EQ(alloc_count_, 1u);
    EXPECT_EQ(free_count_, 1u);
  }

  void* Alloc(size_t s) override {
    EXPECT_LT(s, 1024ull);
    EXPECT_EQ(alloc_count_, free_count_);
    ++alloc_count_;
    return bytes_.begin();
  }

  void Free(void*) override {
    ++free_count_;
  }

  uint32_t AllocCount() const {
    return alloc_count_;
  }
  uint32_t FreeCount() const {
    return free_count_;
  }

 private:
  std::array<uint8_t, 1024> bytes_;
  uint32_t alloc_count_;
  uint32_t free_count_;
};

TEST(BitVector, MovementFree) {
  SingleAllocator alloc;
  {
    BitVector bv(16, false, &alloc);
    bv.SetBit(13);
    EXPECT_EQ(alloc.FreeCount(), 0u);
    EXPECT_EQ(alloc.AllocCount(), 1u);
    ASSERT_TRUE(bv.GetRawStorage() != nullptr);
    EXPECT_TRUE(bv.IsBitSet(13));
    {
      BitVector bv2(std::move(bv));
      // NOLINTNEXTLINE - checking underlying storage has been freed
      ASSERT_TRUE(bv.GetRawStorage() == nullptr);
      EXPECT_TRUE(bv2.IsBitSet(13));
      EXPECT_EQ(alloc.FreeCount(), 0u);
      EXPECT_EQ(alloc.AllocCount(), 1u);
    }
    EXPECT_EQ(alloc.FreeCount(), 1u);
    EXPECT_EQ(alloc.AllocCount(), 1u);
  }
  EXPECT_EQ(alloc.FreeCount(), 1u);
  EXPECT_EQ(alloc.AllocCount(), 1u);
}

}  // namespace art