IAttributeEstimator.h

#pragma once

#include <fsdk/IObject.h>
#include <fsdk/FSDKError.h>
#include <fsdk/Optional.h>
#include <fsdk/Types.h>

#include <algorithm>

namespace fsdk {

#ifndef DOXYGEN_SHOULD_SKIP_THIS
    DECLARE_SMARTPTR(IAttributeEstimator);

    struct EthnicityEstimation {
        float africanAmerican;
        float indian;
        float asian;
        float caucasian;

        enum Ethnicities {
            AfricanAmerican = 0,
            Indian,
            Asian,
            Caucasian,
            Count
        };

        inline Ethnicities getPredominantEthnicity() const;

        inline float getEthnicityScore(Ethnicities ethnicity) const;
    };

    struct IAttributeEstimator : IRefCounted {

        enum EstimationRequest {
            estimateAge       = 1 << 0, 
            estimateGender    = 1 << 1, 
            estimateEthnicity = 1 << 2, 
            estimateAll       = 0xffff  
        };

        struct EstimationResult {
            Optional<float> age;
            Optional<float> gender;
            Optional<float> genderScore;
            Optional<EthnicityEstimation> ethnicity;
        };

        virtual Result<FSDKError> estimate(
            const Image& warp,
            const IAttributeEstimator::EstimationRequest request,
            IAttributeEstimator::EstimationResult& out) const noexcept = 0;

        virtual ResultValue<FSDKError, IAttributeEstimator::EstimationResult> estimate(
            const Span<const Image> warps,
            const IAttributeEstimator::EstimationRequest request,
            Span<IAttributeEstimator::EstimationResult> results) const noexcept = 0;
    };

    using EstimationRequest = IAttributeEstimator::EstimationRequest;
    using AttributeEstimationResult = IAttributeEstimator::EstimationResult;

    /*
        Implementation details.
    */
    EthnicityEstimation::Ethnicities 
    EthnicityEstimation::getPredominantEthnicity() const {
        const float* arr = &this->africanAmerican;
        return static_cast<EthnicityEstimation::Ethnicities>(
            std::distance(arr, std::max_element(arr, arr+EthnicityEstimation::Count))
        );
    }

    /*
        Implementation details.
    */
    float 
    EthnicityEstimation::getEthnicityScore(
        EthnicityEstimation::Ethnicities ethnicity
    ) const {
        return *(&this->africanAmerican + static_cast<uint32_t>(ethnicity));
    }

    /*
        Implementation details.
    */
    inline IAttributeEstimator::EstimationRequest 
    operator|(
        IAttributeEstimator::EstimationRequest first, 
        IAttributeEstimator::EstimationRequest second
    ) {
        return static_cast<IAttributeEstimator::EstimationRequest>(
            static_cast<int>(first) | static_cast<int>(second)
        );
    }

#endif /* DOXYGEN_SHOULD_SKIP_THIS */

} // namespace sdk