weex_core/Source/include/wtf/MediaTime.h

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
#ifndef WTF_MediaTime_h
#define WTF_MediaTime_h

#include <wtf/FastMalloc.h>

#include <cmath>
#include <limits>
#include <math.h>
#include <stdint.h>

namespace WTF {

class PrintStream;

class WTF_EXPORT_PRIVATE MediaTime {
    WTF_MAKE_FAST_ALLOCATED;
public:
    enum {
        Valid = 1 << 0,
        HasBeenRounded = 1 << 1,
        PositiveInfinite = 1 << 2,
        NegativeInfinite = 1 << 3,
        Indefinite = 1 << 4,
        DoubleValue = 1 << 5,
    };

    MediaTime();
    MediaTime(int64_t value, uint32_t scale, uint8_t flags = Valid);
    MediaTime(const MediaTime& rhs);
    ~MediaTime();

    static MediaTime createWithFloat(float floatTime);
    static MediaTime createWithFloat(float floatTime, uint32_t timeScale);
    static MediaTime createWithDouble(double doubleTime);
    static MediaTime createWithDouble(double doubleTime, uint32_t timeScale);

    float toFloat() const;
    double toDouble() const;

    MediaTime& operator=(const MediaTime& rhs);
    MediaTime& operator+=(const MediaTime& rhs) { return *this = *this + rhs; }
    MediaTime& operator-=(const MediaTime& rhs) { return *this = *this - rhs; }
    MediaTime operator+(const MediaTime& rhs) const;
    MediaTime operator-(const MediaTime& rhs) const;
    MediaTime operator-() const;
    MediaTime operator*(int32_t) const;
    bool operator<(const MediaTime& rhs) const { return compare(rhs) == LessThan; }
    bool operator>(const MediaTime& rhs) const { return compare(rhs) == GreaterThan; }
    bool operator!=(const MediaTime& rhs) const { return compare(rhs) != EqualTo; }
    bool operator==(const MediaTime& rhs) const { return compare(rhs) == EqualTo; }
    bool operator>=(const MediaTime& rhs) const { return compare(rhs) >= EqualTo; }
    bool operator<=(const MediaTime& rhs) const { return compare(rhs) <= EqualTo; }
    bool operator!() const;
    explicit operator bool() const;

    typedef enum {
        LessThan = -1,
        EqualTo = 0,
        GreaterThan = 1,
    } ComparisonFlags;

    ComparisonFlags compare(const MediaTime& rhs) const;
    bool isBetween(const MediaTime&, const MediaTime&) const;

    bool isValid() const { return m_timeFlags & Valid; }
    bool isInvalid() const { return !isValid(); }
    bool hasBeenRounded() const { return m_timeFlags & HasBeenRounded; }
    bool isPositiveInfinite() const { return m_timeFlags & PositiveInfinite; }
    bool isNegativeInfinite() const { return m_timeFlags & NegativeInfinite; }
    bool isIndefinite() const { return m_timeFlags & Indefinite; }
    bool hasDoubleValue() const { return m_timeFlags & DoubleValue; }

    static const MediaTime& zeroTime();
    static const MediaTime& invalidTime();
    static const MediaTime& positiveInfiniteTime();
    static const MediaTime& negativeInfiniteTime();
    static const MediaTime& indefiniteTime();

    const int64_t& timeValue() const { return m_timeValue; }
    const uint32_t& timeScale() const { return m_timeScale; }

    void dump(PrintStream& out) const;

    // Make the following casts errors:
    operator double() const = delete;
    MediaTime(double) = delete;
    operator int() const = delete;
    MediaTime(int) = delete;

    friend WTF_EXPORT_PRIVATE MediaTime abs(const MediaTime& rhs);

    static const uint32_t DefaultTimeScale = 10000000;
    static const uint32_t MaximumTimeScale;

    enum class RoundingFlags {
        HalfAwayFromZero = 0,
        TowardZero,
        AwayFromZero,
        TowardPositiveInfinity,
        TowardNegativeInfinity,
    };

    MediaTime toTimeScale(uint32_t, RoundingFlags = RoundingFlags::HalfAwayFromZero) const;

    template<class Encoder> void encode(Encoder&) const;
    template<class Decoder> static bool decode(Decoder&, MediaTime&);

private:
    void setTimeScale(uint32_t, RoundingFlags = RoundingFlags::HalfAwayFromZero);

    union {
        int64_t m_timeValue;
        double m_timeValueAsDouble;
    };
    uint32_t m_timeScale;
    uint8_t m_timeFlags;
};

inline MediaTime operator*(int32_t lhs, const MediaTime& rhs) { return rhs.operator*(lhs); }

WTF_EXPORT_PRIVATE extern MediaTime abs(const MediaTime& rhs);

template<class Encoder>
void MediaTime::encode(Encoder& encoder) const
{
    encoder << m_timeValue << m_timeScale << m_timeFlags;
}

template<class Decoder>
bool MediaTime::decode(Decoder& decoder, MediaTime& time)
{
    return decoder.decode(time.m_timeValue)
        && decoder.decode(time.m_timeScale)
        && decoder.decode(time.m_timeFlags);
}

}

using WTF::MediaTime;
using WTF::abs;

#endif