/*
 * Copyright (c) 2012, Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef LayoutUnit_h
#define LayoutUnit_h

#include "platform/PlatformExport.h"
#include "wtf/Allocator.h"
#include "wtf/Assertions.h"
#include "wtf/MathExtras.h"
#include "wtf/SaturatedArithmetic.h"
#include "wtf/text/WTFString.h"
#include <algorithm>
#include <limits.h>
#include <limits>
#include <stdlib.h>

namespace blink {

#if DCHECK_IS_ON()
#define REPORT_OVERFLOW(doesOverflow)                                          \
  DLOG_IF(ERROR, !(doesOverflow)) << "LayoutUnit overflow !(" << #doesOverflow \
                                  << ") in " << WTF_PRETTY_FUNCTION
#else
#define REPORT_OVERFLOW(doesOverflow) ((void)0)
#endif

static const int kLayoutUnitFractionalBits = 6;
static const int kFixedPointDenominator = 1 << kLayoutUnitFractionalBits;

const int intMaxForLayoutUnit = INT_MAX / kFixedPointDenominator;
const int intMinForLayoutUnit = INT_MIN / kFixedPointDenominator;

// TODO(thakis): Remove these two lines once http://llvm.org/PR26504 is resolved
class PLATFORM_EXPORT LayoutUnit;
inline bool operator<(const LayoutUnit&, const LayoutUnit&);

class LayoutUnit {
  DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();

 public:
  LayoutUnit() : m_value(0) {}
  explicit LayoutUnit(int value) { setValue(value); }
  explicit LayoutUnit(unsigned short value) { setValue(value); }
  explicit LayoutUnit(unsigned value) { setValue(value); }
  explicit LayoutUnit(unsigned long value) {
    m_value = clampTo<int>(value * kFixedPointDenominator);
  }
  explicit LayoutUnit(unsigned long long value) {
    m_value = clampTo<int>(value * kFixedPointDenominator);
  }
  explicit LayoutUnit(float value) {
    m_value = clampTo<int>(value * kFixedPointDenominator);
  }
  explicit LayoutUnit(double value) {
    m_value = clampTo<int>(value * kFixedPointDenominator);
  }

  static LayoutUnit fromFloatCeil(float value) {
    LayoutUnit v;
    v.m_value = clampTo<int>(ceilf(value * kFixedPointDenominator));
    return v;
  }

  static LayoutUnit fromFloatFloor(float value) {
    LayoutUnit v;
    v.m_value = clampTo<int>(floorf(value * kFixedPointDenominator));
    return v;
  }

  static LayoutUnit fromFloatRound(float value) {
    if (value >= 0)
      return clamp(value + epsilon() / 2.0f);
    return clamp(value - epsilon() / 2.0f);
  }

  int toInt() const { return m_value / kFixedPointDenominator; }
  float toFloat() const {
    return static_cast<float>(m_value) / kFixedPointDenominator;
  }
  double toDouble() const {
    return static_cast<double>(m_value) / kFixedPointDenominator;
  }
  float ceilToFloat() const {
    float floatValue = toFloat();
    if (static_cast<int>(floatValue * kFixedPointDenominator) == m_value)
      return floatValue;
    if (floatValue > 0)
      return nextafterf(floatValue, std::numeric_limits<float>::max());
    return nextafterf(floatValue, std::numeric_limits<float>::min());
  }
  unsigned toUnsigned() const {
    REPORT_OVERFLOW(m_value >= 0);
    return toInt();
  }

  // Conversion to int or unsigned is lossy. 'explicit' on these operators won't
  // work because there are also other implicit conversion paths (e.g. operator
  // bool then to int which would generate wrong result). Use toInt() and
  // toUnsigned() instead.
  operator int() const = delete;
  operator unsigned() const = delete;

  operator double() const { return toDouble(); }
  operator float() const { return toFloat(); }
  operator bool() const { return m_value; }

  LayoutUnit operator++(int) {
    m_value += kFixedPointDenominator;
    return *this;
  }

  inline int rawValue() const { return m_value; }
  inline void setRawValue(int value) { m_value = value; }
  void setRawValue(long long value) {
    REPORT_OVERFLOW(value > std::numeric_limits<int>::min() &&
                    value < std::numeric_limits<int>::max());
    m_value = static_cast<int>(value);
  }

  LayoutUnit abs() const {
    LayoutUnit returnValue;
    returnValue.setRawValue(::abs(m_value));
    return returnValue;
  }
  int ceil() const {
    if (UNLIKELY(m_value >= INT_MAX - kFixedPointDenominator + 1))
      return intMaxForLayoutUnit;

    if (m_value >= 0)
      return (m_value + kFixedPointDenominator - 1) / kFixedPointDenominator;
    return toInt();
  }
  ALWAYS_INLINE int round() const {
    return saturatedAddition(rawValue(), kFixedPointDenominator / 2) >>
           kLayoutUnitFractionalBits;
  }

  int floor() const {
    if (UNLIKELY(m_value <= INT_MIN + kFixedPointDenominator - 1))
      return intMinForLayoutUnit;

    return m_value >> kLayoutUnitFractionalBits;
  }

  LayoutUnit clampNegativeToZero() const {
    return std::max(*this, LayoutUnit());
  }

  LayoutUnit clampPositiveToZero() const {
    return std::min(*this, LayoutUnit());
  }

  LayoutUnit fraction() const {
    // Add the fraction to the size (as opposed to the full location) to avoid
    // overflows.  Compute fraction using the mod operator to preserve the sign
    // of the value as it may affect rounding.
    LayoutUnit fraction;
    fraction.setRawValue(rawValue() % kFixedPointDenominator);
    return fraction;
  }

  bool mightBeSaturated() const {
    return rawValue() == std::numeric_limits<int>::max() ||
           rawValue() == std::numeric_limits<int>::min();
  }

  static float epsilon() { return 1.0f / kFixedPointDenominator; }

  static const LayoutUnit max() {
    LayoutUnit m;
    m.m_value = std::numeric_limits<int>::max();
    return m;
  }
  static const LayoutUnit min() {
    LayoutUnit m;
    m.m_value = std::numeric_limits<int>::min();
    return m;
  }

  // Versions of max/min that are slightly smaller/larger than max/min() to
  // allow for roinding without overflowing.
  static const LayoutUnit nearlyMax() {
    LayoutUnit m;
    m.m_value = std::numeric_limits<int>::max() - kFixedPointDenominator / 2;
    return m;
  }
  static const LayoutUnit nearlyMin() {
    LayoutUnit m;
    m.m_value = std::numeric_limits<int>::min() + kFixedPointDenominator / 2;
    return m;
  }

  static LayoutUnit clamp(double value) {
    return clampTo<LayoutUnit>(value, LayoutUnit::min(), LayoutUnit::max());
  }

  String toString() const;

 private:
  static bool isInBounds(int value) {
    return ::abs(value) <=
           std::numeric_limits<int>::max() / kFixedPointDenominator;
  }
  static bool isInBounds(unsigned value) {
    return value <= static_cast<unsigned>(std::numeric_limits<int>::max()) /
                        kFixedPointDenominator;
  }
  static bool isInBounds(double value) {
    return ::fabs(value) <=
           std::numeric_limits<int>::max() / kFixedPointDenominator;
  }

  ALWAYS_INLINE void setValue(int value) {
    m_value = saturatedSet<kLayoutUnitFractionalBits>(value);
  }

  inline void setValue(unsigned value) {
    m_value = saturatedSet<kLayoutUnitFractionalBits>(value);
  }

  int m_value;
};

inline bool operator<=(const LayoutUnit& a, const LayoutUnit& b) {
  return a.rawValue() <= b.rawValue();
}

inline bool operator<=(const LayoutUnit& a, float b) {
  return a.toFloat() <= b;
}

inline bool operator<=(const LayoutUnit& a, int b) {
  return a <= LayoutUnit(b);
}

inline bool operator<=(const float a, const LayoutUnit& b) {
  return a <= b.toFloat();
}

inline bool operator<=(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) <= b;
}

inline bool operator>=(const LayoutUnit& a, const LayoutUnit& b) {
  return a.rawValue() >= b.rawValue();
}

inline bool operator>=(const LayoutUnit& a, int b) {
  return a >= LayoutUnit(b);
}

inline bool operator>=(const float a, const LayoutUnit& b) {
  return a >= b.toFloat();
}

inline bool operator>=(const LayoutUnit& a, float b) {
  return a.toFloat() >= b;
}

inline bool operator>=(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) >= b;
}

inline bool operator<(const LayoutUnit& a, const LayoutUnit& b) {
  return a.rawValue() < b.rawValue();
}

inline bool operator<(const LayoutUnit& a, int b) {
  return a < LayoutUnit(b);
}

inline bool operator<(const LayoutUnit& a, float b) {
  return a.toFloat() < b;
}

inline bool operator<(const LayoutUnit& a, double b) {
  return a.toDouble() < b;
}

inline bool operator<(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) < b;
}

inline bool operator<(const float a, const LayoutUnit& b) {
  return a < b.toFloat();
}

inline bool operator>(const LayoutUnit& a, const LayoutUnit& b) {
  return a.rawValue() > b.rawValue();
}

inline bool operator>(const LayoutUnit& a, double b) {
  return a.toDouble() > b;
}

inline bool operator>(const LayoutUnit& a, float b) {
  return a.toFloat() > b;
}

inline bool operator>(const LayoutUnit& a, int b) {
  return a > LayoutUnit(b);
}

inline bool operator>(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) > b;
}

inline bool operator>(const float a, const LayoutUnit& b) {
  return a > b.toFloat();
}

inline bool operator>(const double a, const LayoutUnit& b) {
  return a > b.toDouble();
}

inline bool operator!=(const LayoutUnit& a, const LayoutUnit& b) {
  return a.rawValue() != b.rawValue();
}

inline bool operator!=(const LayoutUnit& a, float b) {
  return a != LayoutUnit(b);
}

inline bool operator!=(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) != b;
}

inline bool operator!=(const LayoutUnit& a, int b) {
  return a != LayoutUnit(b);
}

inline bool operator==(const LayoutUnit& a, const LayoutUnit& b) {
  return a.rawValue() == b.rawValue();
}

inline bool operator==(const LayoutUnit& a, int b) {
  return a == LayoutUnit(b);
}

inline bool operator==(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) == b;
}

inline bool operator==(const LayoutUnit& a, float b) {
  return a.toFloat() == b;
}

inline bool operator==(const float a, const LayoutUnit& b) {
  return a == b.toFloat();
}

// For multiplication that's prone to overflow, this bounds it to
// LayoutUnit::max() and ::min()
inline LayoutUnit boundedMultiply(const LayoutUnit& a, const LayoutUnit& b) {
  int64_t result = static_cast<int64_t>(a.rawValue()) *
                   static_cast<int64_t>(b.rawValue()) / kFixedPointDenominator;
  int32_t high = static_cast<int32_t>(result >> 32);
  int32_t low = static_cast<int32_t>(result);
  uint32_t saturated =
      (static_cast<uint32_t>(a.rawValue() ^ b.rawValue()) >> 31) +
      std::numeric_limits<int>::max();
  // If the higher 32 bits does not match the lower 32 with sign extension the
  // operation overflowed.
  if (high != low >> 31)
    result = saturated;

  LayoutUnit returnVal;
  returnVal.setRawValue(static_cast<int>(result));
  return returnVal;
}

inline LayoutUnit operator*(const LayoutUnit& a, const LayoutUnit& b) {
  return boundedMultiply(a, b);
}

inline double operator*(const LayoutUnit& a, double b) {
  return a.toDouble() * b;
}

inline float operator*(const LayoutUnit& a, float b) {
  return a.toFloat() * b;
}

inline LayoutUnit operator*(const LayoutUnit& a, int b) {
  return a * LayoutUnit(b);
}

inline LayoutUnit operator*(const LayoutUnit& a, unsigned short b) {
  return a * LayoutUnit(b);
}

inline LayoutUnit operator*(const LayoutUnit& a, unsigned b) {
  return a * LayoutUnit(b);
}

inline LayoutUnit operator*(const LayoutUnit& a, unsigned long b) {
  return a * LayoutUnit(b);
}

inline LayoutUnit operator*(const LayoutUnit& a, unsigned long long b) {
  return a * LayoutUnit(b);
}

inline LayoutUnit operator*(unsigned short a, const LayoutUnit& b) {
  return LayoutUnit(a) * b;
}

inline LayoutUnit operator*(unsigned a, const LayoutUnit& b) {
  return LayoutUnit(a) * b;
}

inline LayoutUnit operator*(unsigned long a, const LayoutUnit& b) {
  return LayoutUnit(a) * b;
}

inline LayoutUnit operator*(unsigned long long a, const LayoutUnit& b) {
  return LayoutUnit(a) * b;
}

inline LayoutUnit operator*(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) * b;
}

inline float operator*(const float a, const LayoutUnit& b) {
  return a * b.toFloat();
}

inline double operator*(const double a, const LayoutUnit& b) {
  return a * b.toDouble();
}

inline LayoutUnit operator/(const LayoutUnit& a, const LayoutUnit& b) {
  LayoutUnit returnVal;
  long long rawVal = static_cast<long long>(kFixedPointDenominator) *
                     a.rawValue() / b.rawValue();
  returnVal.setRawValue(clampTo<int>(rawVal));
  return returnVal;
}

inline float operator/(const LayoutUnit& a, float b) {
  return a.toFloat() / b;
}

inline double operator/(const LayoutUnit& a, double b) {
  return a.toDouble() / b;
}

inline LayoutUnit operator/(const LayoutUnit& a, int b) {
  return a / LayoutUnit(b);
}

inline LayoutUnit operator/(const LayoutUnit& a, unsigned short b) {
  return a / LayoutUnit(b);
}

inline LayoutUnit operator/(const LayoutUnit& a, unsigned b) {
  return a / LayoutUnit(b);
}

inline LayoutUnit operator/(const LayoutUnit& a, unsigned long b) {
  return a / LayoutUnit(b);
}

inline LayoutUnit operator/(const LayoutUnit& a, unsigned long long b) {
  return a / LayoutUnit(b);
}

inline float operator/(const float a, const LayoutUnit& b) {
  return a / b.toFloat();
}

inline double operator/(const double a, const LayoutUnit& b) {
  return a / b.toDouble();
}

inline LayoutUnit operator/(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) / b;
}

inline LayoutUnit operator/(unsigned short a, const LayoutUnit& b) {
  return LayoutUnit(a) / b;
}

inline LayoutUnit operator/(unsigned a, const LayoutUnit& b) {
  return LayoutUnit(a) / b;
}

inline LayoutUnit operator/(unsigned long a, const LayoutUnit& b) {
  return LayoutUnit(a) / b;
}

inline LayoutUnit operator/(unsigned long long a, const LayoutUnit& b) {
  return LayoutUnit(a) / b;
}

ALWAYS_INLINE LayoutUnit operator+(const LayoutUnit& a, const LayoutUnit& b) {
  LayoutUnit returnVal;
  returnVal.setRawValue(saturatedAddition(a.rawValue(), b.rawValue()));
  return returnVal;
}

inline LayoutUnit operator+(const LayoutUnit& a, int b) {
  return a + LayoutUnit(b);
}

inline float operator+(const LayoutUnit& a, float b) {
  return a.toFloat() + b;
}

inline double operator+(const LayoutUnit& a, double b) {
  return a.toDouble() + b;
}

inline LayoutUnit operator+(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) + b;
}

inline float operator+(const float a, const LayoutUnit& b) {
  return a + b.toFloat();
}

inline double operator+(const double a, const LayoutUnit& b) {
  return a + b.toDouble();
}

ALWAYS_INLINE LayoutUnit operator-(const LayoutUnit& a, const LayoutUnit& b) {
  LayoutUnit returnVal;
  returnVal.setRawValue(saturatedSubtraction(a.rawValue(), b.rawValue()));
  return returnVal;
}

inline LayoutUnit operator-(const LayoutUnit& a, int b) {
  return a - LayoutUnit(b);
}

inline LayoutUnit operator-(const LayoutUnit& a, unsigned b) {
  return a - LayoutUnit(b);
}

inline float operator-(const LayoutUnit& a, float b) {
  return a.toFloat() - b;
}

inline double operator-(const LayoutUnit& a, double b) {
  return a.toDouble() - b;
}

inline LayoutUnit operator-(const int a, const LayoutUnit& b) {
  return LayoutUnit(a) - b;
}

inline float operator-(const float a, const LayoutUnit& b) {
  return a - b.toFloat();
}

inline LayoutUnit operator-(const LayoutUnit& a) {
  LayoutUnit returnVal;
  returnVal.setRawValue(saturatedNegative(a.rawValue()));
  return returnVal;
}

// For returning the remainder after a division with integer results.
inline LayoutUnit intMod(const LayoutUnit& a, const LayoutUnit& b) {
  // This calculates the modulo so that: a = static_cast<int>(a / b) * b +
  // intMod(a, b).
  LayoutUnit returnVal;
  returnVal.setRawValue(a.rawValue() % b.rawValue());
  return returnVal;
}

inline LayoutUnit operator%(const LayoutUnit& a, const LayoutUnit& b) {
  // This calculates the modulo so that: a = (a / b) * b + a % b.
  LayoutUnit returnVal;
  long long rawVal =
      (static_cast<long long>(kFixedPointDenominator) * a.rawValue()) %
      b.rawValue();
  returnVal.setRawValue(rawVal / kFixedPointDenominator);
  return returnVal;
}

inline LayoutUnit operator%(const LayoutUnit& a, int b) {
  return a % LayoutUnit(b);
}

inline LayoutUnit operator%(int a, const LayoutUnit& b) {
  return LayoutUnit(a) % b;
}

inline LayoutUnit& operator+=(LayoutUnit& a, const LayoutUnit& b) {
  a.setRawValue(saturatedAddition(a.rawValue(), b.rawValue()));
  return a;
}

inline LayoutUnit& operator+=(LayoutUnit& a, int b) {
  a = a + LayoutUnit(b);
  return a;
}

inline LayoutUnit& operator+=(LayoutUnit& a, float b) {
  a = LayoutUnit(a + b);
  return a;
}

inline float& operator+=(float& a, const LayoutUnit& b) {
  a = a + b;
  return a;
}

inline LayoutUnit& operator-=(LayoutUnit& a, int b) {
  a = a - LayoutUnit(b);
  return a;
}

inline LayoutUnit& operator-=(LayoutUnit& a, const LayoutUnit& b) {
  a.setRawValue(saturatedSubtraction(a.rawValue(), b.rawValue()));
  return a;
}

inline LayoutUnit& operator-=(LayoutUnit& a, float b) {
  a = LayoutUnit(a - b);
  return a;
}

inline float& operator-=(float& a, const LayoutUnit& b) {
  a = a - b;
  return a;
}

inline LayoutUnit& operator*=(LayoutUnit& a, const LayoutUnit& b) {
  a = a * b;
  return a;
}

inline LayoutUnit& operator*=(LayoutUnit& a, float b) {
  a = LayoutUnit(a * b);
  return a;
}

inline float& operator*=(float& a, const LayoutUnit& b) {
  a = a * b;
  return a;
}

inline LayoutUnit& operator/=(LayoutUnit& a, const LayoutUnit& b) {
  a = a / b;
  return a;
}

inline LayoutUnit& operator/=(LayoutUnit& a, float b) {
  a = LayoutUnit(a / b);
  return a;
}

inline float& operator/=(float& a, const LayoutUnit& b) {
  a = a / b;
  return a;
}

inline int snapSizeToPixel(LayoutUnit size, LayoutUnit location) {
  LayoutUnit fraction = location.fraction();
  return (fraction + size).round() - fraction.round();
}

inline int roundToInt(LayoutUnit value) {
  return value.round();
}

inline int floorToInt(LayoutUnit value) {
  return value.floor();
}

inline LayoutUnit absoluteValue(const LayoutUnit& value) {
  return value.abs();
}

inline LayoutUnit layoutMod(const LayoutUnit& numerator,
                            const LayoutUnit& denominator) {
  return numerator % denominator;
}

inline LayoutUnit layoutMod(const LayoutUnit& numerator, int denominator) {
  return numerator % LayoutUnit(denominator);
}

inline bool isIntegerValue(const LayoutUnit value) {
  return value.toInt() == value;
}

inline LayoutUnit clampToLayoutUnit(LayoutUnit value,
                                    LayoutUnit min,
                                    LayoutUnit max) {
  if (value >= max)
    return max;
  if (value <= min)
    return min;
  return value;
}

inline std::ostream& operator<<(std::ostream& stream, const LayoutUnit& value) {
  return stream << value.toString();
}

}  // namespace blink

#endif  // LayoutUnit_h