value.hpp

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#ifndef value_hpp
#define value_hpp
#include <iomanip>
#include <iostream>
#include <sstream>
#include <utility>
#include <algorithm>
#include <map>
#include <vector>
#include <tuple>
#include <initializer_list>
#include <functional>

#include "log.hpp"

namespace fv{

/* bool in_register_function = false; */
template<typename> class Function; // undefined
class GenFunction {
    private:
        std::string name;
        std::string impl;
    protected:
        inline static bool in_register_function=false;

    public:
        inline static std::map<const std::string, GenFunction*> function_registry;

        GenFunction(const std::string& name, const std::string& impl)
          :impl(impl),
           name(name){
        }
        virtual ~GenFunction() { };

        std::string& get_name(){
            return name;
        }

        static std::string format_code(const std::string& code){
            std::stringstream code_out("");
            std::string command("echo \""+code+"\" | clang-format");
            char buffer[255];
            FILE *stream = popen(command.c_str(), "r");
            while (fgets(buffer, 255, stream) != NULL)
                code_out << buffer;
            if (pclose(stream) == 0)
                return code_out.str();
            else
                return code;
        }

        static std::string summary(){
            std::stringstream ss;
            ss << "The following functions have been registered" << std::endl;
            for(auto p : function_registry){
                if (p.second == nullptr) continue;
                ss << "-->" << p.second->name << std::endl;
                ss << format_code(p.second->impl);
            }
            return ss.str();
        }

        template <typename T>
        static Function<T>& register_function(const std::string& name, std::function<T> f, const std::string& impl){
            in_register_function = true;
            Function<T>* func;
            if (GenFunction::function_registry[name] != nullptr){
                func = dynamic_cast<Function<T>*>(GenFunction::function_registry[name]);
                if (func == nullptr){
                    ERROR("Trying to register function which has already been registered with a different type");
                }
            } else {
                func = new Function<T>(name, impl, f);
                GenFunction::function_registry[name] = func;
            }
            in_register_function = false;
            return *func;
        }
};


template <typename R, typename... ArgTypes>
class Function<R(ArgTypes...)> : public GenFunction {
    private:
        std::function<R(ArgTypes...)> f;

    public:
        Function(const std::string& name, const std::string& impl, std::function<R(ArgTypes...)> f)
          :GenFunction(name, impl), f(f){
            if (!in_register_function) {
                WARNING("Don't instantiate Function objects directly! Use GenFunction::register_function instead.");
            }
          }
        Function(const std::string& name, std::function<R(ArgTypes...)> f)
          :Function(name, "N/A", f){ }
        ~Function() { }

        R operator()(ArgTypes ...args){
            return f(args...);
        }

};


#define FUNC(f) f, #f

class GenValue;
typedef std::map<std::string, GenValue*> ValueSet;
class GenValue{
    private:
        std::string name;
    protected:
        virtual void _reset() = 0;
        inline static std::map<const std::string, GenValue*> values;
        inline static std::map<const std::string, GenValue*> aliases;
    public:
        GenValue(const std::string& name, const std::string& alias)
          :name(name){
            values[name] = this;
            if (alias != "")
                GenValue::alias(alias, this);
        }

        const std::string& get_name(){
            return name;
        }

        static void reset(){
            for (auto val : values){
                val.second->_reset();
            }
        }

        static GenValue* get_value(const std::string& name){
            if (aliases[name] != nullptr)
                return aliases[name];
            else if (values[name] != nullptr)
                return values[name];
            else{
                ERROR("Could not find alias or value \"" << name << "\". I'll tell you the ones I know about." << std::endl
                        << summary());
                CRITICAL("Aborting... :(", -1);
            }
        }

        static void alias(const std::string& name, GenValue* value){
            if (aliases[name] != nullptr){
                WARNING("WARNING: alias \"" << name << "\" overrides previous entry.");
            }
            aliases[name] = value;
        }

        static GenValue* alias(const std::string& name){
            if (values[name] != nullptr){
                WARNING("Alias \"" << name << "\" does not exist.");
            }
            return aliases[name];
        }

        static std::string summary(){
            std::stringstream ss;
            ss << "The following values have been created: " << std::endl;
            for (auto value : values){
                if (value.second == nullptr) continue;
                ss << "\t\"" << value.first << "\" at address " << value.second << std::endl;
            }
            ss << "And these aliases:" << std::endl;
            for (auto alias : aliases){
                std::string orig("VOID");
                if (alias.second == nullptr) continue;
                for (auto value : values){
                    if (alias.second == value.second){
                        orig = value.second->get_name();
                        break;
                    }
                }
                ss << "\t\"" << alias.first << "\" referring to \"" << orig << "\"" << std::endl;
            }
            return ss.str();
        }
        friend std::ostream& operator<<(std::ostream& os, const GenValue& gv);
};
std::ostream& operator<<(std::ostream& os, GenValue& gv){
    os << gv.get_name();
    return os;
}


template <typename T>
class Value : public GenValue{
    public:
        Value(const std::string& name, const std::string& alias="")
          :GenValue(name, alias){ }
        virtual T& get_value() = 0;
};


template <typename T>
class ObservedValue : public Value<T>{
    private:
        T *val_ref;
        void _reset(){ }
    public:
        ObservedValue(const std::string& name, T* val_ref, const std::string& alias="")
          :Value<T>(name, alias),
           val_ref(val_ref){ }
        T& get_value(){
            return *val_ref;
        }
};


template <typename T>
class DerivedValue : public Value<T>{
    private:
        void _reset(){
            value_valid = false;
        }
    protected:
        T value;
        bool value_valid;

        virtual void update_value() = 0;
    public:
        DerivedValue(const std::string& name, const std::string& alias="")
          :Value<T>(name, alias),
           value_valid(false) { }

        T& get_value(){
            if (!value_valid){
                update_value();
                value_valid = true;
            }
            return value;
        }
};


template <typename T>
class WrapperVector : public DerivedValue<std::vector<T> >{
    private:
        Value<int>* size;
        Value<T*>* data;

        void update_value(){
            int n = size->get_value();
            T* data_ref = data->get_value();
            this->value.assign(data_ref, data_ref+n);
        }

    public:
        WrapperVector(Value<int>* size, Value<T*>* data, const std::string& alias="")
          :DerivedValue<std::vector<T> >("vectorOf("+size->get_name()+","+data->get_name()+")", alias),
           size(size), data(data){ }

        WrapperVector(const std::string &label_size, const std::string &label_data, const std::string& alias="")
          :WrapperVector(dynamic_cast<Value<int>*>(GenValue::get_value(label_size)),
                         dynamic_cast<Value<T*>*>(GenValue::get_value(label_data)), alias) { }
};

template <typename T1, typename T2>
class Pair : public DerivedValue<std::pair<T1, T2> >{
    protected:
        std::pair<Value<T1>*, Value<T2>* > value_pair;
        void update_value(){
            this->value.first = value_pair.first->get_value();
            this->value.second = value_pair.second->get_value();
        }
    public:
        Pair(Value<T1> *value1, Value<T2> *value2, const std::string alias="")
          :DerivedValue<std::pair<T1, T2> >("pair("+value1->get_name()+","+value2->get_name()+")", alias),
           value_pair(value1, value2){ }
        Pair(const std::string& label1, const std::string& label2, const std::string alias="")
          :Pair(dynamic_cast<Value<T1>*>(GenValue::get_value(label1)),
                dynamic_cast<Value<T1>*>(GenValue::get_value(label2)),
                alias){ }
};

template <typename R, typename T>
class ZipMapFour : public DerivedValue<std::vector<R> >{
    private:
        Function<R(T, T, T, T)>& f;
        Value<std::vector<T> >* v1;
        Value<std::vector<T> >* v2;
        Value<std::vector<T> >* v3;
        Value<std::vector<T> >* v4;

        void update_value(){
            std::vector<T> v1_val = v1->get_value();
            std::vector<T> v2_val = v2->get_value();
            std::vector<T> v3_val = v3->get_value();
            std::vector<T> v4_val = v4->get_value();

            int n;
            std::tie(n, std::ignore) = std::minmax({v1_val.size(), v2_val.size(), v3_val.size(), v4_val.size()});
            this->value.resize(n);
            for (int i=0; i<n; i++){
                this->value[i] = f(v1_val[i], v2_val[i], v3_val[i], v4_val[i]);
            }
        }

    public:
        ZipMapFour(Function<R(T, T, T, T)>& f,
                   Value<std::vector<T> >* v1, Value<std::vector<T> >* v2,
                   Value<std::vector<T> >* v3, Value<std::vector<T> >* v4, const std::string alias="")
          :DerivedValue<std::vector<R> >("zipmap("+f.get_name()+":"+v1->get_name()+","+v2->get_name()+","+
                                                                    v3->get_name()+","+v4->get_name()+")", alias),
           f(f), v1(v1), v2(v2), v3(v3), v4(v4) { }

        ZipMapFour(Function<R(T, T, T, T)>& f,
                   const std::string& label1, const std::string& label2,
                   const std::string& label3, const std::string& label4, const std::string alias="")
          :ZipMapFour(f,
                      dynamic_cast<Value<std::vector<T> >*>(GenValue::get_value(label1)),
                      dynamic_cast<Value<std::vector<T> >*>(GenValue::get_value(label2)),
                      dynamic_cast<Value<std::vector<T> >*>(GenValue::get_value(label3)),
                      dynamic_cast<Value<std::vector<T> >*>(GenValue::get_value(label4)),
                      alias){ }
};

template<typename T>
class Count : public DerivedValue<int>{
    private:
        Function<bool(T)>& selector;
        Value<std::vector<T> >* v;
        void update_value(){
            value = 0;
            for(auto val : v->get_value()){
                if(selector(val))
                    value++;
            }
        }
    public:
        Count(Function<bool(T)>& selector, Value<std::vector<T>>* v, const std::string alias="")
          :DerivedValue<int>("count("+selector.get_name()+":"+v->get_name()+")", alias),
           selector(selector), v(v) { }

        Count(Function<bool(T)>& selector, const std::string& v_name, const std::string alias="")
          :Count(selector, dynamic_cast<Value<std::vector<T> >*>(GenValue::get_value(v_name)), alias) { }
};


template <typename T>
class Reduce : public DerivedValue<T>{
    private:
        Function<T(std::vector<T>)>& reduce;
        Value<std::vector<T> >* v;
        void update_value(){
            this->value = reduce(v->get_value());
        }
    public:
        Reduce(Function<T(std::vector<T>)>& reduce, Value<std::vector<T> >* v, const std::string alias="")
          :DerivedValue<T>("reduceWith("+reduce.get_name()+":"+v->get_name()+")", alias),
           reduce(reduce), v(v) { }

        Reduce(Function<T(std::vector<T>)>& reduce, const std::string& v_name, const std::string alias="")
          :Reduce(reduce, dynamic_cast<Value<std::vector<T> >*>(GenValue::get_value(v_name)), alias) { }
};

template <typename T>
class Max : public Reduce<T>{
    public:
        Max(const std::string& v_name, const std::string alias="")
          :Reduce<T>(GenFunction::register_function<T(std::vector<T>)>("max",
                      FUNC(([](std::vector<T> vec){
                          return *std::max_element(vec.begin(), vec.end());}))),
                      v_name, alias) { }
};

template <typename T>
class Min : public Reduce<T>{
    public:
        Min(const std::string& v_name, const std::string alias="")
          :Reduce<T>(GenFunction::register_function<T(std::vector<T>)>("min",
                      FUNC(([](std::vector<T> vec){
                         return *std::min_element(vec.begin(), vec.end());}))),
                     v_name, alias) { }
};

template <typename T>
class Mean : public Reduce<T>{
    public:
        Mean(const std::string& v_name, const std::string alias="")
          :Reduce<T>(GenFunction::register_function<T(std::vector<T>)>("mean",
                      FUNC(([](std::vector<T> vec){
                        int n = 0; T sum = 0;
                        for (T e : vec){ n++; sum += e; }
                        return n>0 ? sum / n : 0; }))),
                     v_name, alias) { }
};

template <typename T>
class Range : public Reduce<T>{
    public:
        Range(const std::string& v_name, const std::string alias="")
          :Reduce<T>(GenFunction::register_function<T(std::vector<T>)>("range",
                      FUNC(([](std::vector<T> vec){
                        auto minmax = std::minmax_element(vec.begin(), vec.end());
                        return (*minmax.second) - (*minmax.first); }))),
                     v_name, alias) { }
};

template <typename T>
class ElementOf : public Reduce<T>{
    public:
        ElementOf(Value<int>* index, const std::string& v_name, const std::string alias="")
          :Reduce<T>(GenFunction::register_function<T(std::vector<T>)>("elementOf",
                      FUNC(([index](std::vector<T> vec){return vec[index->get_value()];}))),
                     v_name, alias) { }
        ElementOf(const std::string& name, int index, const std::string& v_name, const std::string alias="")
          :Reduce<T>(name, [index](std::vector<T> vec){return vec[index];}, v_name, alias) { }
};

template <typename T>
class ReduceIndex : public DerivedValue<std::pair<T, int> >{
    private:
        Function<std::pair<T,int>(std::vector<T>)>& reduce;
        Value<std::vector<T> >* v;
        void update_value(){
            this->value = reduce(v->get_value());
        }
    public:
        ReduceIndex(Function<std::pair<T,int>(std::vector<T>)>& reduce, Value<std::vector<T> >* v, const std::string alias="")
          :DerivedValue<T>("reduceIndexWith("+reduce.get_name()+":"+v->get_name()+")", alias),
           reduce(reduce), v(v) { }

        ReduceIndex(Function<std::pair<T,int>(std::vector<T>)>& reduce, const std::string& v_name, const std::string alias="")
          :ReduceIndex(reduce, dynamic_cast<Value<std::vector<T> >*>(GenValue::get_value(v_name)), alias) { }
};

template <typename T>
class MaxIndex : public ReduceIndex<T>{
    public:
        MaxIndex(const std::string& v_name, const std::string alias="")
          :ReduceIndex<T>(GenFunction::register_function<T(std::vector<T>)>("maxIndex",
                      FUNC(([](std::vector<T> vec){
                               auto elptr = std::max_element(vec.begin(), vec.end());
                               return std::pair<T,int>(*elptr, int(elptr-vec.begin())); }
                          ))), v_name, alias) { }
};

template <typename T>
class MinIndex : public ReduceIndex<T>{
    public:
        MinIndex(const std::string& v_name, const std::string alias="")
          :ReduceIndex<T>(GenFunction::register_function<T(std::vector<T>)>("minIndex",
                      FUNC(([](std::vector<T> vec){
                               auto elptr = std::min_element(vec.begin(), vec.end());
                               return std::pair<T,int>(*elptr, int(elptr-vec.begin())); }
                          ))), v_name, alias) { }
};

template <typename T>
class BoundValue : public DerivedValue<T>{
    protected:
        Function<T()>& f;
        void update_value(){
            this->value = f();
        }
    public:
        BoundValue(Function<T()>& f, const std::string alias="")
          :DerivedValue<T>(f.get_name()+"(<bound>)", alias),
           f(f) { }
};

template <typename T>
class PointerValue : public DerivedValue<T*>{
    protected:
        void update_value(){ }
    public:
        PointerValue(const std::string& name, T* ptr, const std::string alias="")
          :DerivedValue<T*>(name, alias){
            this->value = ptr;
        }
};

template <typename T>
class ConstantValue : public DerivedValue<T>{
    protected:
        T const_value;
        void update_value(){
            this->value = const_value;
        }
    public:
        ConstantValue(const std::string& name, T const_value, const std::string alias="")
            :DerivedValue<T>("const::"+name, alias),
             const_value(const_value) { }
};
}
#endif // value_hpp