// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <stdint.h>

#include <limits>

#include "base/logging.h"
#include "net/base/int128.h"
#include "testing/gtest/include/gtest/gtest.h"

using net::uint128;
using net::uint128_pod;
using net::kuint128max;

TEST(Int128, AllTests) {
  uint128 zero(0);
  uint128 one(1);
  uint128 one_2arg(0, 1);
  uint128 two(0, 2);
  uint128 three(0, 3);
  uint128 big(2000, 2);
  uint128 big_minus_one(2000, 1);
  uint128 bigger(2001, 1);
  uint128 biggest(kuint128max);
  uint128 high_low(1, 0);
  uint128 low_high(0, std::numeric_limits<uint64_t>::max());
  EXPECT_LT(one, two);
  EXPECT_GT(two, one);
  EXPECT_LT(one, big);
  EXPECT_LT(one, big);
  EXPECT_EQ(one, one_2arg);
  EXPECT_NE(one, two);
  EXPECT_GT(big, one);
  EXPECT_GE(big, two);
  EXPECT_GE(big, big_minus_one);
  EXPECT_GT(big, big_minus_one);
  EXPECT_LT(big_minus_one, big);
  EXPECT_LE(big_minus_one, big);
  EXPECT_NE(big_minus_one, big);
  EXPECT_LT(big, biggest);
  EXPECT_LE(big, biggest);
  EXPECT_GT(biggest, big);
  EXPECT_GE(biggest, big);
  EXPECT_EQ(big, ~~big);
  EXPECT_EQ(one, one | one);
  EXPECT_EQ(big, big | big);
  EXPECT_EQ(one, one | zero);
  EXPECT_EQ(one, one & one);
  EXPECT_EQ(big, big & big);
  EXPECT_EQ(zero, one & zero);
  EXPECT_EQ(zero, big & ~big);
  EXPECT_EQ(zero, one ^ one);
  EXPECT_EQ(zero, big ^ big);
  EXPECT_EQ(one, one ^ zero);
  EXPECT_EQ(big, big << 0);
  EXPECT_EQ(big, big >> 0);
  EXPECT_GT(big << 1, big);
  EXPECT_LT(big >> 1, big);
  EXPECT_EQ(big, (big << 10) >> 10);
  EXPECT_EQ(big, (big >> 1) << 1);
  EXPECT_EQ(one, (one << 80) >> 80);
  EXPECT_EQ(zero, (one >> 80) << 80);
  EXPECT_EQ(zero, big >> 128);
  EXPECT_EQ(zero, big << 128);
  EXPECT_EQ(Uint128High64(biggest), std::numeric_limits<uint64_t>::max());
  EXPECT_EQ(Uint128Low64(biggest), std::numeric_limits<uint64_t>::max());
  EXPECT_EQ(zero + one, one);
  EXPECT_EQ(one + one, two);
  EXPECT_EQ(big_minus_one + one, big);
  EXPECT_EQ(one - one, zero);
  EXPECT_EQ(one - zero, one);
  EXPECT_EQ(zero - one, biggest);
  EXPECT_EQ(big - big, zero);
  EXPECT_EQ(big - one, big_minus_one);
  EXPECT_EQ(big + std::numeric_limits<uint64_t>::max(), bigger);
  EXPECT_EQ(biggest + 1, zero);
  EXPECT_EQ(zero - 1, biggest);
  EXPECT_EQ(high_low - one, low_high);
  EXPECT_EQ(low_high + one, high_low);
  EXPECT_EQ(Uint128High64((uint128(1) << 64) - 1), 0u);
  EXPECT_EQ(Uint128Low64((uint128(1) << 64) - 1),
            std::numeric_limits<uint64_t>::max());
  EXPECT_TRUE(!!one);
  EXPECT_TRUE(!!high_low);
  EXPECT_FALSE(!!zero);
  EXPECT_FALSE(!one);
  EXPECT_FALSE(!high_low);
  EXPECT_TRUE(!zero);
  EXPECT_TRUE(zero == 0);
  EXPECT_FALSE(zero != 0);
  EXPECT_FALSE(one == 0);
  EXPECT_TRUE(one != 0);

  uint128 test = zero;
  EXPECT_EQ(++test, one);
  EXPECT_EQ(test, one);
  EXPECT_EQ(test++, one);
  EXPECT_EQ(test, two);
  EXPECT_EQ(test -= 2, zero);
  EXPECT_EQ(test, zero);
  EXPECT_EQ(test += 2, two);
  EXPECT_EQ(test, two);
  EXPECT_EQ(--test, one);
  EXPECT_EQ(test, one);
  EXPECT_EQ(test--, one);
  EXPECT_EQ(test, zero);
  EXPECT_EQ(test |= three, three);
  EXPECT_EQ(test &= one, one);
  EXPECT_EQ(test ^= three, two);
  EXPECT_EQ(test >>= 1, one);
  EXPECT_EQ(test <<= 1, two);

  EXPECT_EQ(big, -(-big));
  EXPECT_EQ(two, -((-one) - 1));
  EXPECT_EQ(kuint128max, -one);
  EXPECT_EQ(zero, -zero);

  LOG(INFO) << one;
  LOG(INFO) << big_minus_one;
}

TEST(Int128, PodTests) {
  uint128_pod pod = { 12345, 67890 };
  uint128 from_pod(pod);
  EXPECT_EQ(12345u, Uint128High64(from_pod));
  EXPECT_EQ(67890u, Uint128Low64(from_pod));

  uint128 zero(0);
  uint128_pod zero_pod = {0, 0};
  uint128 one(1);
  uint128_pod one_pod = {0, 1};
  uint128 two(2);
  uint128_pod two_pod = {0, 2};
  uint128 three(3);
  uint128_pod three_pod = {0, 3};
  uint128 big(1, 0);
  uint128_pod big_pod = {1, 0};

  EXPECT_EQ(zero, zero_pod);
  EXPECT_EQ(zero_pod, zero);
  EXPECT_EQ(zero_pod, zero_pod);
  EXPECT_EQ(one, one_pod);
  EXPECT_EQ(one_pod, one);
  EXPECT_EQ(one_pod, one_pod);
  EXPECT_EQ(two, two_pod);
  EXPECT_EQ(two_pod, two);
  EXPECT_EQ(two_pod, two_pod);

  EXPECT_NE(one, two_pod);
  EXPECT_NE(one_pod, two);
  EXPECT_NE(one_pod, two_pod);

  EXPECT_LT(one, two_pod);
  EXPECT_LT(one_pod, two);
  EXPECT_LT(one_pod, two_pod);
  EXPECT_LE(one, one_pod);
  EXPECT_LE(one_pod, one);
  EXPECT_LE(one_pod, one_pod);
  EXPECT_LE(one, two_pod);
  EXPECT_LE(one_pod, two);
  EXPECT_LE(one_pod, two_pod);

  EXPECT_GT(two, one_pod);
  EXPECT_GT(two_pod, one);
  EXPECT_GT(two_pod, one_pod);
  EXPECT_GE(two, two_pod);
  EXPECT_GE(two_pod, two);
  EXPECT_GE(two_pod, two_pod);
  EXPECT_GE(two, one_pod);
  EXPECT_GE(two_pod, one);
  EXPECT_GE(two_pod, one_pod);

  EXPECT_EQ(three, one | two_pod);
  EXPECT_EQ(three, one_pod | two);
  EXPECT_EQ(three, one_pod | two_pod);
  EXPECT_EQ(one, three & one_pod);
  EXPECT_EQ(one, three_pod & one);
  EXPECT_EQ(one, three_pod & one_pod);
  EXPECT_EQ(two, three ^ one_pod);
  EXPECT_EQ(two, three_pod ^ one);
  EXPECT_EQ(two, three_pod ^ one_pod);
  EXPECT_EQ(two, three & (~one));
  EXPECT_EQ(three, ~~three);

  EXPECT_EQ(two, two_pod << 0);
  EXPECT_EQ(two, one_pod << 1);
  EXPECT_EQ(big, one_pod << 64);
  EXPECT_EQ(zero, one_pod << 128);
  EXPECT_EQ(two, two_pod >> 0);
  EXPECT_EQ(one, two_pod >> 1);
  EXPECT_EQ(one, big_pod >> 64);

  EXPECT_EQ(one, zero + one_pod);
  EXPECT_EQ(one, zero_pod + one);
  EXPECT_EQ(one, zero_pod + one_pod);
  EXPECT_EQ(one, two - one_pod);
  EXPECT_EQ(one, two_pod - one);
  EXPECT_EQ(one, two_pod - one_pod);
}

TEST(Int128, OperatorAssignReturnRef) {
  uint128 v(1);
  (v += 4) -= 3;
  EXPECT_EQ(2, v);
}

TEST(Int128, Multiply) {
  uint128 a, b, c;

  // Zero test.
  a = 0;
  b = 0;
  c = a * b;
  EXPECT_EQ(0, c);

  // Max carries.
  a = uint128(0) - 1;
  b = uint128(0) - 1;
  c = a * b;
  EXPECT_EQ(1, c);

  // Self-operation with max carries.
  c = uint128(0) - 1;
  c *= c;
  EXPECT_EQ(1, c);

  // 1-bit x 1-bit.
  for (int i = 0; i < 64; ++i) {
    for (int j = 0; j < 64; ++j) {
      a = uint128(1) << i;
      b = uint128(1) << j;
      c = a * b;
      EXPECT_EQ(uint128(1) << (i+j), c);
    }
  }

  // Verified with dc.
  a = uint128(0xffffeeeeddddccccULL, 0xbbbbaaaa99998888ULL);
  b = uint128(0x7777666655554444ULL, 0x3333222211110000ULL);
  c = a * b;
  EXPECT_EQ(uint128(0x530EDA741C71D4C3ULL, 0xBF25975319080000ULL), c);
  EXPECT_EQ(0, c - b * a);
  EXPECT_EQ(a*a - b*b, (a+b) * (a-b));

  // Verified with dc.
  a = uint128(0x0123456789abcdefULL, 0xfedcba9876543210ULL);
  b = uint128(0x02468ace13579bdfULL, 0xfdb97531eca86420ULL);
  c = a * b;
  EXPECT_EQ(uint128(0x97a87f4f261ba3f2ULL, 0x342d0bbf48948200ULL), c);
  EXPECT_EQ(0, c - b * a);
  EXPECT_EQ(a*a - b*b, (a+b) * (a-b));
}

TEST(Int128, AliasTests) {
  uint128 x1(1, 2);
  uint128 x2(2, 4);
  x1 += x1;
  EXPECT_EQ(x2, x1);

  uint128 x3(1, 1ull << 63);
  uint128 x4(3, 0);
  x3 += x3;
  EXPECT_EQ(x4, x3);
}