/*
 *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "webrtc/modules/include/module_common_types.h"

#include "webrtc/test/gtest.h"

namespace webrtc {

TEST(IsNewerSequenceNumber, Equal) {
  EXPECT_FALSE(IsNewerSequenceNumber(0x0001, 0x0001));
}

TEST(IsNewerSequenceNumber, NoWrap) {
  EXPECT_TRUE(IsNewerSequenceNumber(0xFFFF, 0xFFFE));
  EXPECT_TRUE(IsNewerSequenceNumber(0x0001, 0x0000));
  EXPECT_TRUE(IsNewerSequenceNumber(0x0100, 0x00FF));
}

TEST(IsNewerSequenceNumber, ForwardWrap) {
  EXPECT_TRUE(IsNewerSequenceNumber(0x0000, 0xFFFF));
  EXPECT_TRUE(IsNewerSequenceNumber(0x0000, 0xFF00));
  EXPECT_TRUE(IsNewerSequenceNumber(0x00FF, 0xFFFF));
  EXPECT_TRUE(IsNewerSequenceNumber(0x00FF, 0xFF00));
}

TEST(IsNewerSequenceNumber, BackwardWrap) {
  EXPECT_FALSE(IsNewerSequenceNumber(0xFFFF, 0x0000));
  EXPECT_FALSE(IsNewerSequenceNumber(0xFF00, 0x0000));
  EXPECT_FALSE(IsNewerSequenceNumber(0xFFFF, 0x00FF));
  EXPECT_FALSE(IsNewerSequenceNumber(0xFF00, 0x00FF));
}

TEST(IsNewerSequenceNumber, HalfWayApart) {
  EXPECT_TRUE(IsNewerSequenceNumber(0x8000, 0x0000));
  EXPECT_FALSE(IsNewerSequenceNumber(0x0000, 0x8000));
}

TEST(IsNewerTimestamp, Equal) {
  EXPECT_FALSE(IsNewerTimestamp(0x00000001, 0x000000001));
}

TEST(IsNewerTimestamp, NoWrap) {
  EXPECT_TRUE(IsNewerTimestamp(0xFFFFFFFF, 0xFFFFFFFE));
  EXPECT_TRUE(IsNewerTimestamp(0x00000001, 0x00000000));
  EXPECT_TRUE(IsNewerTimestamp(0x00010000, 0x0000FFFF));
}

TEST(IsNewerTimestamp, ForwardWrap) {
  EXPECT_TRUE(IsNewerTimestamp(0x00000000, 0xFFFFFFFF));
  EXPECT_TRUE(IsNewerTimestamp(0x00000000, 0xFFFF0000));
  EXPECT_TRUE(IsNewerTimestamp(0x0000FFFF, 0xFFFFFFFF));
  EXPECT_TRUE(IsNewerTimestamp(0x0000FFFF, 0xFFFF0000));
}

TEST(IsNewerTimestamp, BackwardWrap) {
  EXPECT_FALSE(IsNewerTimestamp(0xFFFFFFFF, 0x00000000));
  EXPECT_FALSE(IsNewerTimestamp(0xFFFF0000, 0x00000000));
  EXPECT_FALSE(IsNewerTimestamp(0xFFFFFFFF, 0x0000FFFF));
  EXPECT_FALSE(IsNewerTimestamp(0xFFFF0000, 0x0000FFFF));
}

TEST(IsNewerTimestamp, HalfWayApart) {
  EXPECT_TRUE(IsNewerTimestamp(0x80000000, 0x00000000));
  EXPECT_FALSE(IsNewerTimestamp(0x00000000, 0x80000000));
}

TEST(LatestSequenceNumber, NoWrap) {
  EXPECT_EQ(0xFFFFu, LatestSequenceNumber(0xFFFF, 0xFFFE));
  EXPECT_EQ(0x0001u, LatestSequenceNumber(0x0001, 0x0000));
  EXPECT_EQ(0x0100u, LatestSequenceNumber(0x0100, 0x00FF));

  EXPECT_EQ(0xFFFFu, LatestSequenceNumber(0xFFFE, 0xFFFF));
  EXPECT_EQ(0x0001u, LatestSequenceNumber(0x0000, 0x0001));
  EXPECT_EQ(0x0100u, LatestSequenceNumber(0x00FF, 0x0100));
}

TEST(LatestSequenceNumber, Wrap) {
  EXPECT_EQ(0x0000u, LatestSequenceNumber(0x0000, 0xFFFF));
  EXPECT_EQ(0x0000u, LatestSequenceNumber(0x0000, 0xFF00));
  EXPECT_EQ(0x00FFu, LatestSequenceNumber(0x00FF, 0xFFFF));
  EXPECT_EQ(0x00FFu, LatestSequenceNumber(0x00FF, 0xFF00));

  EXPECT_EQ(0x0000u, LatestSequenceNumber(0xFFFF, 0x0000));
  EXPECT_EQ(0x0000u, LatestSequenceNumber(0xFF00, 0x0000));
  EXPECT_EQ(0x00FFu, LatestSequenceNumber(0xFFFF, 0x00FF));
  EXPECT_EQ(0x00FFu, LatestSequenceNumber(0xFF00, 0x00FF));
}

TEST(LatestTimestamp, NoWrap) {
  EXPECT_EQ(0xFFFFFFFFu, LatestTimestamp(0xFFFFFFFF, 0xFFFFFFFE));
  EXPECT_EQ(0x00000001u, LatestTimestamp(0x00000001, 0x00000000));
  EXPECT_EQ(0x00010000u, LatestTimestamp(0x00010000, 0x0000FFFF));
}

TEST(LatestTimestamp, Wrap) {
  EXPECT_EQ(0x00000000u, LatestTimestamp(0x00000000, 0xFFFFFFFF));
  EXPECT_EQ(0x00000000u, LatestTimestamp(0x00000000, 0xFFFF0000));
  EXPECT_EQ(0x0000FFFFu, LatestTimestamp(0x0000FFFF, 0xFFFFFFFF));
  EXPECT_EQ(0x0000FFFFu, LatestTimestamp(0x0000FFFF, 0xFFFF0000));

  EXPECT_EQ(0x00000000u, LatestTimestamp(0xFFFFFFFF, 0x00000000));
  EXPECT_EQ(0x00000000u, LatestTimestamp(0xFFFF0000, 0x00000000));
  EXPECT_EQ(0x0000FFFFu, LatestTimestamp(0xFFFFFFFF, 0x0000FFFF));
  EXPECT_EQ(0x0000FFFFu, LatestTimestamp(0xFFFF0000, 0x0000FFFF));
}


TEST(SequenceNumberUnwrapper, Limits) {
  SequenceNumberUnwrapper unwrapper;

  EXPECT_EQ(0, unwrapper.Unwrap(0));
  EXPECT_EQ(0x8000, unwrapper.Unwrap(0x8000));
  // Delta is exactly 0x8000 but current is lower than input, wrap backwards.
  EXPECT_EQ(0x0, unwrapper.Unwrap(0x0000));

  EXPECT_EQ(0x8000, unwrapper.Unwrap(0x8000));
  EXPECT_EQ(0xFFFF, unwrapper.Unwrap(0xFFFF));
  EXPECT_EQ(0x10000, unwrapper.Unwrap(0x0000));
  EXPECT_EQ(0xFFFF, unwrapper.Unwrap(0xFFFF));
  EXPECT_EQ(0x8000, unwrapper.Unwrap(0x8000));
  EXPECT_EQ(0, unwrapper.Unwrap(0));

  // Don't allow negative values.
  EXPECT_EQ(0xFFFF, unwrapper.Unwrap(0xFFFF));
}

TEST(SequenceNumberUnwrapper, ForwardWraps) {
  int64_t seq = 0;
  SequenceNumberUnwrapper unwrapper;

  const int kMaxIncrease = 0x8000 - 1;
  const int kNumWraps = 4;
  for (int i = 0; i < kNumWraps * 2; ++i) {
    int64_t unwrapped = unwrapper.Unwrap(static_cast<uint16_t>(seq & 0xFFFF));
    EXPECT_EQ(seq, unwrapped);
    seq += kMaxIncrease;
  }

  unwrapper.UpdateLast(0);
  for (int seq = 0; seq < kNumWraps * 0xFFFF; ++seq) {
    int64_t unwrapped = unwrapper.Unwrap(static_cast<uint16_t>(seq & 0xFFFF));
    EXPECT_EQ(seq, unwrapped);
  }
}

TEST(SequenceNumberUnwrapper, BackwardWraps) {
  SequenceNumberUnwrapper unwrapper;

  const int kMaxDecrease = 0x8000 - 1;
  const int kNumWraps = 4;
  int64_t seq = kNumWraps * 2 * kMaxDecrease;
  unwrapper.UpdateLast(seq);
  for (int i = kNumWraps * 2; i >= 0; --i) {
    int64_t unwrapped = unwrapper.Unwrap(static_cast<uint16_t>(seq & 0xFFFF));
    EXPECT_EQ(seq, unwrapped);
    seq -= kMaxDecrease;
  }

  seq = kNumWraps * 0xFFFF;
  unwrapper.UpdateLast(seq);
  for (; seq >= 0; --seq) {
    int64_t unwrapped = unwrapper.Unwrap(static_cast<uint16_t>(seq & 0xFFFF));
    EXPECT_EQ(seq, unwrapped);
  }
}

}  // namespace webrtc
