EnumDescriptor.hpp

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#pragma once
 
#include "AstGlobal.h"
#include "AstUtil/Span.hpp"
#include <string>       // for std::string
#include <vector>       // for std::vector
#include <utility>      // for std::pair
 
 
AST_NAMESPACE_BEGIN
 
class AST_UTIL_API EnumDescriptorData
{   
public:
    using NumberType = int;                                // 枚举值类型
    using ValueList = Span<std::pair<NumberType, char*>>;  // 枚举值列表
public:
    EnumDescriptorData() = default;
    ~EnumDescriptorData() = default;
 
    EnumDescriptorData(ValueList values) : values_(values) {}
 
public:
    const char* nameOf(NumberType value) const;
 
    NumberType valueOf(StringView name) const;
 
    NumberType valueOf(StringView name, bool& found) const;
 
private:
    ValueList values_;  
};
 
template<typename EnumType>
class EnumDescriptor: public EnumDescriptorData
{
public:
    using EnumDescriptorData::EnumDescriptorData;
    static_assert(std::is_enum<EnumType>::value, "EnumType must be an enum type");
    static_assert(sizeof(NumberType) >= sizeof(EnumType), "sizeof(NumberType) must be at least sizeof(EnumType) in order to store EnumType");
 
    const char* nameOf(EnumType value) const
    {
        return EnumDescriptorData::nameOf(static_cast<NumberType>(value));
    }
 
    EnumType valueOf(StringView name) const
    {
        return static_cast<EnumType>(EnumDescriptorData::valueOf(name));
    }
 
    EnumType valueOf(StringView name, bool& found) const
    {
        return static_cast<EnumType>(EnumDescriptorData::valueOf(name, found));
    }
};
 
template<typename EnumType>
EnumDescriptor<EnumType>& aEnumDescriptor();
 
 
#define AST_ENUM_VALUE(Enumerator, Name)  {static_cast<EnumDescriptorData::NumberType>(_EnumType::Enumerator), const_cast<char*>(Name)}
 
#define AST_ENUM_DESCRIPTOR(EnumType, ...) \
    template<> \
    EnumDescriptor<EnumType>& aEnumDescriptor<EnumType>() \
    { \
        using _EnumType = EnumType; \
        static_assert(sizeof(EnumType) <= sizeof(EnumDescriptorData::NumberType), "size of " #EnumType " must be less than or equal to size of EnumDescriptorData::NumberType"); \
        static std::pair<EnumDescriptorData::NumberType, char*> _values[] = {__VA_ARGS__}; \
        static EnumDescriptor<EnumType> descriptor{_values}; \
        return descriptor; \
    }
 
 
AST_NAMESPACE_END