timeCode.h

//
// Copyright 2016 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_USD_USD_TIME_CODE_H
#define PXR_USD_USD_TIME_CODE_H

#include "pxr/pxr.h"
#include "pxr/usd/usd/api.h"
#include "pxr/usd/sdf/layerOffset.h"
#include "pxr/usd/sdf/timeCode.h"
#include "pxr/base/arch/hints.h"
#include "pxr/base/tf/staticTokens.h"
#include "pxr/base/tf/hash.h"

#include <limits>
#include <iosfwd>
#include <cmath>


PXR_NAMESPACE_OPEN_SCOPE


#define USD_TIME_CODE_TOKENS \
    (DEFAULT) \
    (EARLIEST) \
    (PRE_TIME)

TF_DECLARE_PUBLIC_TOKENS(UsdTimeCodeTokens, USD_API, USD_TIME_CODE_TOKENS);


class UsdTimeCode {
public:
    constexpr UsdTimeCode(double t = 0.0) noexcept : _value(t) {}

    constexpr UsdTimeCode(const GfTimeCode &timeCode) noexcept 
        : _value(timeCode.GetValue()) {}

    static constexpr UsdTimeCode PreTime(double t) noexcept {
        return UsdTimeCode(t, /*isPreTime=*/true);
    }

    static constexpr UsdTimeCode PreTime(const GfTimeCode& timeCode) noexcept {
        return UsdTimeCode(timeCode.GetValue(), /*isPreTime=*/true);
    }

    static constexpr UsdTimeCode EarliestTime() {
        return UsdTimeCode(std::numeric_limits<double>::lowest());
    }

    static constexpr UsdTimeCode Default() {
        return UsdTimeCode(std::numeric_limits<double>::quiet_NaN());
    }

    static constexpr double
    SafeStep(double maxValue=1e6, double maxCompression=10.0) {
        return std::numeric_limits<double>::epsilon() *
            maxValue * maxCompression * 2.0;
    }

    bool IsPreTime() const {
        return _isPreTime;
    }

    bool IsEarliestTime() const {
        return IsNumeric() && (_value == std::numeric_limits<double>::lowest());
    }

    bool IsDefault() const {
        return std::isnan(_value);
    }

    bool IsNumeric() const {
        return !IsDefault();
    }

    double GetValue() const {
        if (ARCH_UNLIKELY(IsDefault()))
            _IssueGetValueOnDefaultError();
        return _value;
    }

    friend bool operator==(const UsdTimeCode &lhs, const UsdTimeCode& rhs) {
        if (lhs.IsDefault() && rhs.IsDefault()) {
            return true;
        }
        return lhs._value == rhs._value && 
               lhs._isPreTime == rhs._isPreTime;
    }

    friend bool operator!=(const UsdTimeCode &lhs, const UsdTimeCode& rhs) {
        return !(lhs == rhs);
    }

    friend bool operator<(const UsdTimeCode &lhs, const UsdTimeCode &rhs) {
        if (lhs.IsDefault() || rhs.IsDefault()) {
            return lhs.IsDefault() && !rhs.IsDefault();
        }
        return lhs._value < rhs._value ||
               (lhs._value == rhs._value && 
                lhs._isPreTime && !rhs._isPreTime);
    }

    friend bool operator>=(const UsdTimeCode &lhs, const UsdTimeCode &rhs) {
        return !(lhs < rhs);
    }

    friend bool operator<=(const UsdTimeCode &lhs, const UsdTimeCode &rhs) {
        return !(rhs < lhs);
    }

    friend bool operator>(const UsdTimeCode &lhs, const UsdTimeCode &rhs) {
        return !(lhs <= rhs);
    }

    friend size_t hash_value(const UsdTimeCode &time) {
        return TfHash::Combine(time._value, time._isPreTime);
    }

private:
    constexpr UsdTimeCode(double t, bool isPreTime) noexcept 
        : _value(t), _isPreTime(isPreTime) {}

    USD_API
    void _IssueGetValueOnDefaultError() const;

    double _value;
    bool _isPreTime = false;
};

// Stream I/O operators.
USD_API
std::ostream& operator<<(std::ostream& os, const UsdTimeCode& time);

USD_API
std::istream& operator>>(std::istream& is, UsdTimeCode& time);

USD_API
UsdTimeCode operator*(const SdfLayerOffset& offset, const UsdTimeCode& time);

PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_USD_USD_TIME_CODE_H