// Copyright 2017 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 "components/zucchini/algorithm.h"

#include <stddef.h>
#include <stdint.h>

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

namespace zucchini {

namespace {

// Casting functions to specify signed 8-bit and 16-bit integer constants.
// For example, signed8(0xFF) == int8_t(-1).
inline int8_t signed8(uint8_t v) {
  return *reinterpret_cast<const int8_t*>(&v);
}

inline int32_t signed16(uint16_t v) {
  return *reinterpret_cast<const int16_t*>(&v);
}

}  // namespace

TEST(AlgorithmTest, RangeIsBounded) {
  // Basic tests.
  EXPECT_TRUE(RangeIsBounded<uint8_t>(0U, +0U, 10U));
  EXPECT_TRUE(RangeIsBounded<uint8_t>(0U, +10U, 10U));
  EXPECT_TRUE(RangeIsBounded<uint8_t>(1U, +9U, 10U));
  EXPECT_FALSE(RangeIsBounded<uint8_t>(1U, +10U, 10U));
  EXPECT_TRUE(RangeIsBounded<uint8_t>(8U, +1U, 10U));
  EXPECT_TRUE(RangeIsBounded<uint8_t>(8U, +2U, 10U));
  EXPECT_TRUE(RangeIsBounded<uint8_t>(9U, +0U, 10U));
  EXPECT_FALSE(RangeIsBounded<uint8_t>(10U, +0U, 10U));  // !
  EXPECT_FALSE(RangeIsBounded<uint8_t>(100U, +0U, 10U));
  EXPECT_FALSE(RangeIsBounded<uint8_t>(100U, +1U, 10U));

  // Test at boundary of overflow.
  EXPECT_TRUE(RangeIsBounded<uint8_t>(42U, +137U, 255U));
  EXPECT_TRUE(RangeIsBounded<uint8_t>(0U, +255U, 255U));
  EXPECT_TRUE(RangeIsBounded<uint8_t>(1U, +254U, 255U));
  EXPECT_FALSE(RangeIsBounded<uint8_t>(1U, +255U, 255U));
  EXPECT_TRUE(RangeIsBounded<uint8_t>(254U, +0U, 255U));
  EXPECT_TRUE(RangeIsBounded<uint8_t>(254U, +1U, 255U));
  EXPECT_FALSE(RangeIsBounded<uint8_t>(255U, +0U, 255U));
  EXPECT_FALSE(RangeIsBounded<uint8_t>(255U, +3U, 255U));

  // Test with uint32_t.
  EXPECT_TRUE(RangeIsBounded<uint32_t>(0U, +0x1000U, 0x2000U));
  EXPECT_TRUE(RangeIsBounded<uint32_t>(0x0FFFU, +0x1000U, 0x2000U));
  EXPECT_TRUE(RangeIsBounded<uint32_t>(0x1000U, +0x1000U, 0x2000U));
  EXPECT_FALSE(RangeIsBounded<uint32_t>(0x1000U, +0x1001U, 0x2000U));
  EXPECT_TRUE(RangeIsBounded<uint32_t>(0x1FFFU, +1U, 0x2000U));
  EXPECT_FALSE(RangeIsBounded<uint32_t>(0x2000U, +0U, 0x2000U));  // !
  EXPECT_FALSE(RangeIsBounded<uint32_t>(0x3000U, +0U, 0x2000U));
  EXPECT_FALSE(RangeIsBounded<uint32_t>(0x3000U, +1U, 0x2000U));
  EXPECT_TRUE(RangeIsBounded<uint32_t>(0U, +0xFFFFFFFEU, 0xFFFFFFFFU));
  EXPECT_TRUE(RangeIsBounded<uint32_t>(0U, +0xFFFFFFFFU, 0xFFFFFFFFU));
  EXPECT_TRUE(RangeIsBounded<uint32_t>(1U, +0xFFFFFFFEU, 0xFFFFFFFFU));
  EXPECT_FALSE(RangeIsBounded<uint32_t>(1U, +0xFFFFFFFFU, 0xFFFFFFFFU));
  EXPECT_TRUE(RangeIsBounded<uint32_t>(0x80000000U, +0x7FFFFFFFU, 0xFFFFFFFFU));
  EXPECT_FALSE(
      RangeIsBounded<uint32_t>(0x80000000U, +0x80000000U, 0xFFFFFFFFU));
  EXPECT_TRUE(RangeIsBounded<uint32_t>(0xFFFFFFFEU, +1U, 0xFFFFFFFFU));
  EXPECT_FALSE(RangeIsBounded<uint32_t>(0xFFFFFFFFU, +0U, 0xFFFFFFFFU));  // !
  EXPECT_FALSE(
      RangeIsBounded<uint32_t>(0xFFFFFFFFU, +0xFFFFFFFFU, 0xFFFFFFFFU));
}

TEST(AlgorithmTest, RangeCovers) {
  // Basic tests.
  EXPECT_TRUE(RangeCovers<uint8_t>(0U, +10U, 0U));
  EXPECT_TRUE(RangeCovers<uint8_t>(0U, +10U, 5U));
  EXPECT_TRUE(RangeCovers<uint8_t>(0U, +10U, 9U));
  EXPECT_FALSE(RangeCovers<uint8_t>(0U, +10U, 10U));
  EXPECT_FALSE(RangeCovers<uint8_t>(0U, +10U, 100U));
  EXPECT_FALSE(RangeCovers<uint8_t>(0U, +10U, 255U));

  EXPECT_FALSE(RangeCovers<uint8_t>(42U, +137U, 0U));
  EXPECT_FALSE(RangeCovers<uint8_t>(42U, +137U, 41U));
  EXPECT_TRUE(RangeCovers<uint8_t>(42U, +137U, 42U));
  EXPECT_TRUE(RangeCovers<uint8_t>(42U, +137U, 100U));
  EXPECT_TRUE(RangeCovers<uint8_t>(42U, +137U, 178U));
  EXPECT_FALSE(RangeCovers<uint8_t>(42U, +137U, 179U));
  EXPECT_FALSE(RangeCovers<uint8_t>(42U, +137U, 255U));

  // 0-size ranges.
  EXPECT_FALSE(RangeCovers<uint8_t>(42U, +0U, 41U));
  EXPECT_FALSE(RangeCovers<uint8_t>(42U, +0U, 42U));
  EXPECT_FALSE(RangeCovers<uint8_t>(42U, +0U, 43U));

  // Test at boundary of overflow.
  EXPECT_TRUE(RangeCovers<uint8_t>(254U, +1U, 254U));
  EXPECT_FALSE(RangeCovers<uint8_t>(254U, +1U, 255U));
  EXPECT_FALSE(RangeCovers<uint8_t>(255U, +0U, 255U));
  EXPECT_TRUE(RangeCovers<uint8_t>(255U, +1U, 255U));
  EXPECT_FALSE(RangeCovers<uint8_t>(255U, +5U, 0U));

  // Test with unit32_t.
  EXPECT_FALSE(RangeCovers<uint32_t>(1234567U, +7654321U, 0U));
  EXPECT_FALSE(RangeCovers<uint32_t>(1234567U, +7654321U, 1234566U));
  EXPECT_TRUE(RangeCovers<uint32_t>(1234567U, +7654321U, 1234567U));
  EXPECT_TRUE(RangeCovers<uint32_t>(1234567U, +7654321U, 4444444U));
  EXPECT_TRUE(RangeCovers<uint32_t>(1234567U, +7654321U, 8888887U));
  EXPECT_FALSE(RangeCovers<uint32_t>(1234567U, +7654321U, 8888888U));
  EXPECT_FALSE(RangeCovers<uint32_t>(1234567U, +7654321U, 0x80000000U));
  EXPECT_FALSE(RangeCovers<uint32_t>(1234567U, +7654321U, 0xFFFFFFFFU));
  EXPECT_FALSE(RangeCovers<uint32_t>(0xFFFFFFFFU, +0, 0xFFFFFFFFU));
  EXPECT_TRUE(RangeCovers<uint32_t>(0xFFFFFFFFU, +1, 0xFFFFFFFFU));
  EXPECT_FALSE(RangeCovers<uint32_t>(0xFFFFFFFFU, +2, 0));
}

TEST(AlgorithmTest, InclusiveClamp) {
  EXPECT_EQ(1U, InclusiveClamp<uint32_t>(0U, 1U, 9U));
  EXPECT_EQ(1U, InclusiveClamp<uint32_t>(1U, 1U, 9U));
  EXPECT_EQ(5U, InclusiveClamp<uint32_t>(5U, 1U, 9U));
  EXPECT_EQ(8U, InclusiveClamp<uint32_t>(8U, 1U, 9U));
  EXPECT_EQ(9U, InclusiveClamp<uint32_t>(9U, 1U, 9U));
  EXPECT_EQ(9U, InclusiveClamp<uint32_t>(10U, 1U, 9U));
  EXPECT_EQ(9U, InclusiveClamp<uint32_t>(0xFFFFFFFFU, 1U, 9U));
  EXPECT_EQ(42U, InclusiveClamp<uint32_t>(0U, 42U, 42U));
  EXPECT_EQ(42U, InclusiveClamp<uint32_t>(41U, 42U, 42U));
  EXPECT_EQ(42U, InclusiveClamp<uint32_t>(42U, 42U, 42U));
  EXPECT_EQ(42U, InclusiveClamp<uint32_t>(43U, 42U, 42U));
  EXPECT_EQ(0U, InclusiveClamp<uint32_t>(0U, 0U, 0U));
  EXPECT_EQ(0xFFFFFFFF,
            InclusiveClamp<uint32_t>(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF));
}

TEST(AlgorithmTest, Ceil) {
  EXPECT_EQ(0U, ceil<uint32_t>(0U, 2U));
  EXPECT_EQ(2U, ceil<uint32_t>(1U, 2U));
  EXPECT_EQ(2U, ceil<uint32_t>(2U, 2U));
  EXPECT_EQ(4U, ceil<uint32_t>(3U, 2U));
  EXPECT_EQ(4U, ceil<uint32_t>(4U, 2U));
  EXPECT_EQ(11U, ceil<uint32_t>(10U, 11U));
  EXPECT_EQ(11U, ceil<uint32_t>(11U, 11U));
  EXPECT_EQ(22U, ceil<uint32_t>(12U, 11U));
  EXPECT_EQ(22U, ceil<uint32_t>(21U, 11U));
  EXPECT_EQ(22U, ceil<uint32_t>(22U, 11U));
  EXPECT_EQ(33U, ceil<uint32_t>(23U, 11U));
}

TEST(AlgorithmTest, SignExtend) {
  // 0x6A = 0b0110'1010.
  EXPECT_EQ(uint8_t(0x00), (SignExtend<uint8_t>(0, 0x6A)));
  EXPECT_EQ(signed8(0xFE), (SignExtend<int8_t>(1, signed8(0x6A))));
  EXPECT_EQ(uint8_t(0x02), (SignExtend<uint8_t>(2, 0x6A)));
  EXPECT_EQ(signed8(0xFA), (SignExtend<int8_t>(3, signed8(0x6A))));
  EXPECT_EQ(uint8_t(0x0A), (SignExtend<uint8_t>(4, 0x6A)));
  EXPECT_EQ(signed8(0xEA), (SignExtend<int8_t>(5, signed8(0x6A))));
  EXPECT_EQ(uint8_t(0xEA), (SignExtend<uint8_t>(6, 0x6A)));
  EXPECT_EQ(signed8(0x6A), (SignExtend<int8_t>(7, signed8(0x6A))));

  EXPECT_EQ(signed16(0xFFFA), (SignExtend<int16_t>(3, 0x6A)));
  EXPECT_EQ(uint16_t(0x000A), (SignExtend<uint16_t>(4, 0x6A)));

  EXPECT_EQ(int32_t(0xFFFF8000), (SignExtend<int32_t>(15, 0x00008000)));
  EXPECT_EQ(uint32_t(0x00008000U), (SignExtend<uint32_t>(16, 0x00008000)));
  EXPECT_EQ(int32_t(0xFFFFFC00), (SignExtend<int32_t>(10, 0x00000400)));
  EXPECT_EQ(uint32_t(0xFFFFFFFFU), (SignExtend<uint32_t>(31, 0xFFFFFFFF)));

  EXPECT_EQ(int64_t(0xFFFFFFFFFFFFFE6ALL),
            (SignExtend<int64_t>(9, 0x000000000000026ALL)));
  EXPECT_EQ(int64_t(0x000000000000016ALL),
            (SignExtend<int64_t>(9, 0xFFFFFFFFFFFFFD6ALL)));
  EXPECT_EQ(uint64_t(0xFFFFFFFFFFFFFE6AULL),
            (SignExtend<uint64_t>(9, 0x000000000000026AULL)));
  EXPECT_EQ(uint64_t(0x000000000000016AULL),
            (SignExtend<uint64_t>(9, 0xFFFFFFFFFFFFFD6AULL)));
}

TEST(AlgorithmTest, SignExtendTemplated) {
  // 0x6A = 0b0110'1010.
  EXPECT_EQ(uint8_t(0x00), (SignExtend<0, uint8_t>(0x6A)));
  EXPECT_EQ(signed8(0xFE), (SignExtend<1, int8_t>(signed8(0x6A))));
  EXPECT_EQ(uint8_t(0x02), (SignExtend<2, uint8_t>(0x6A)));
  EXPECT_EQ(signed8(0xFA), (SignExtend<3, int8_t>(signed8(0x6A))));
  EXPECT_EQ(uint8_t(0x0A), (SignExtend<4, uint8_t>(0x6A)));
  EXPECT_EQ(signed8(0xEA), (SignExtend<5, int8_t>(signed8(0x6A))));
  EXPECT_EQ(uint8_t(0xEA), (SignExtend<6, uint8_t>(0x6A)));
  EXPECT_EQ(signed8(0x6A), (SignExtend<7, int8_t>(signed8(0x6A))));

  EXPECT_EQ(signed16(0xFFFA), (SignExtend<3, int16_t>(0x6A)));
  EXPECT_EQ(uint16_t(0x000A), (SignExtend<4, uint16_t>(0x6A)));

  EXPECT_EQ(int32_t(0xFFFF8000), (SignExtend<15, int32_t>(0x00008000)));
  EXPECT_EQ(uint32_t(0x00008000U), (SignExtend<16, uint32_t>(0x00008000)));
  EXPECT_EQ(int32_t(0xFFFFFC00), (SignExtend<10, int32_t>(0x00000400)));
  EXPECT_EQ(uint32_t(0xFFFFFFFFU), (SignExtend<31, uint32_t>(0xFFFFFFFF)));

  EXPECT_EQ(int64_t(0xFFFFFFFFFFFFFE6ALL),
            (SignExtend<9, int64_t>(0x000000000000026ALL)));
  EXPECT_EQ(int64_t(0x000000000000016ALL),
            (SignExtend<9, int64_t>(0xFFFFFFFFFFFFFD6ALL)));
  EXPECT_EQ(uint64_t(0xFFFFFFFFFFFFFE6AULL),
            (SignExtend<9, uint64_t>(0x000000000000026AULL)));
  EXPECT_EQ(uint64_t(0x000000000000016AULL),
            (SignExtend<9, uint64_t>(0xFFFFFFFFFFFFFD6AULL)));
}

}  // namespace zucchini