timeCode.h

//
// Copyright 2016 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache 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/timeCode.h"
#include "pxr/base/arch/hints.h"
#include "pxr/base/tf/staticTokens.h"

#include <boost/functional/hash.hpp>

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


PXR_NAMESPACE_OPEN_SCOPE


#define USD_TIME_CODE_TOKENS \
    (DEFAULT) \
    (EARLIEST)

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 SdfTimeCode &timeCode) noexcept 
        : _value(timeCode.GetValue()) {}

    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 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) {
        return lhs.IsDefault() == rhs.IsDefault() &&
            (lhs.IsDefault() || (lhs.GetValue() == rhs.GetValue()));
    }

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

    friend bool operator<(const UsdTimeCode &lhs, const UsdTimeCode &rhs) {
        return (lhs.IsDefault() && rhs.IsNumeric()) ||
            (lhs.IsNumeric() && rhs.IsNumeric() &&
             lhs.GetValue() < rhs.GetValue());
    }

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

    friend bool operator<=(const UsdTimeCode &lhs, const UsdTimeCode &rhs) {
        return lhs.IsDefault() || 
            (rhs.IsNumeric() && lhs.GetValue() <= rhs.GetValue());
    }

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

    friend size_t hash_value(const UsdTimeCode &time) {
        return boost::hash_value(time._value);
    }

private:
    USD_API
    void _IssueGetValueOnDefaultError() const;

    double _value;
};

// 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);


PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_USD_USD_TIME_CODE_H