Class CConstVariant

• Defined in File constvariant.h

Class Documentation

class CConstVariant

Variant class to store const values.

This class is used for the storage of all possible data types as well as solving the expressions in const assignments. Only 32-bit, 64-bit integers, largest floating point and several string data type variations are used. The conversion rules for data types follow the C++11 conversion rules:

• Assignment of data type:

  • Signed integers are assigned to int32_t when smaller than 64-bit; otherwise are assigned to int64_t.

  • Unsigned integers are assigned to uint32_t when smaller than 64-bit; otherwise are assigned to uint64_t.

  • Integral signed data types are: char, short, long, long long, int8_t, int16_t, int32_t int64_t.

  • Integral unsigned data types are: bool, unsigned short, unsigned long, unsigned long long, uint8_t, uint16_t, uint32_t uint64_t, wchar_t, char16_t, char32_t.

  • String objects and string pointers are assigned to their corresponding counterparts.

• Arithmic operations with two operands:

  • If either operand is long double, the other operand is converted to long double.

  • If both integral operands are signed or both are unsigned, the operand with lesser conversion rank is converted to the

  • operand with the greater conversion rank.

  • Otherwise, if the unsigned integral operand’s conversion rank is greater or equal to the conversion rank of the signed operand, the signed operand is converted to the unsigned operand’s type.

  • Otherwise, if the signed integral operand’s type can represent all values of the unsigned operand, the unsigned operand is converted to the signed operand’s type.

  • Otherwise, both integral operands are converted to the unsigned counterpart of the signed operand’s type.

  • Conversions with and between string based operands are not supported.

• Cast to data type:

  • If the stored data type and target data type are both signed or both unsigned, the target data type boundaries are checked with the value before assignment takes place.

  • If the destination type is unsigned, the resulting value is the smallest unsigned value equal to the source value modulo 2^n where n is the number of bits used to represent the destination type.

  • If the destination type is signed, the value does not change if the source integer can be represented in the destination type.

Unnamed Group

bool IsArithmetic() const

Meta information.

Remark

The ranking function provides a number indicating the ranking of the type.

Returns:

Returns ‘true’ when the type stored in the variant has the specific attribute; ‘false’ otherwise.

bool IsIntegral() const

Meta information.

Remark

The ranking function provides a number indicating the ranking of the type.

Returns:

Returns ‘true’ when the type stored in the variant has the specific attribute; ‘false’ otherwise.

bool IsFloatingPoint() const

Meta information.

Remark

The ranking function provides a number indicating the ranking of the type.

Returns:

Returns ‘true’ when the type stored in the variant has the specific attribute; ‘false’ otherwise.

bool IsBoolean() const

Meta information.

Remark

The ranking function provides a number indicating the ranking of the type.

Returns:

Returns ‘true’ when the type stored in the variant has the specific attribute; ‘false’ otherwise.

bool IsSigned() const

Meta information.

Remark

The ranking function provides a number indicating the ranking of the type.

Returns:

Returns ‘true’ when the type stored in the variant has the specific attribute; ‘false’ otherwise.

bool IsUnsigned() const

Meta information.

Remark

The ranking function provides a number indicating the ranking of the type.

Returns:

Returns ‘true’ when the type stored in the variant has the specific attribute; ‘false’ otherwise.

size_t Ranking() const

Meta information.

Remark

The ranking function provides a number indicating the ranking of the type.

Returns:

Returns ‘true’ when the type stored in the variant has the specific attribute; ‘false’ otherwise.

template<typename TType>
bool IsSame() const

Meta information.

Remark

The ranking function provides a number indicating the ranking of the type.

Returns:

Returns ‘true’ when the type stored in the variant has the specific attribute; ‘false’ otherwise.

Unnamed Group

CConstVariant operator!() const

Unary arithmetic operators.

Remark

The bit operator ‘~’ and the logical operator ‘!’ work with integral operands only.

Returns:

The result of the operation.

CConstVariant operator~() const

Unary arithmetic operators.

Remark

The bit operator ‘~’ and the logical operator ‘!’ work with integral operands only.

Returns:

The result of the operation.

CConstVariant operator+() const

Unary arithmetic operators.

Remark

The bit operator ‘~’ and the logical operator ‘!’ work with integral operands only.

Returns:

The result of the operation.

CConstVariant operator-() const

Unary arithmetic operators.

Remark

The bit operator ‘~’ and the logical operator ‘!’ work with integral operands only.

Returns:

The result of the operation.

Unnamed Group

template<typename TFunction>
static CConstVariant UnaryOperation(const CConstVariant &rvarOperand, TFunction tOperation)

Do unary operation. The first version allows the operation on any arithmetic type. The second version works for integral operation only.

Template Parameters:

TFunction – The function type that should do the operation. The function uses the prototype:

CConstVariant(auto tOperand); 

Parameters:

• rvarOperand – [in] The operand.

• tOperation – [in] The function that is used for the operation.

Returns:

The const variant with the result.

template<typename TFunction>
static CConstVariant UnaryOperationIntegral(const CConstVariant &rvarOperand, TFunction tOperation)

Do unary operation. The first version allows the operation on any arithmetic type. The second version works for integral operation only.

Template Parameters:

TFunction – The function type that should do the operation. The function uses the prototype:

CConstVariant(auto tOperand); 

Parameters:

• rvarOperand – [in] The operand.

• tOperation – [in] The function that is used for the operation.

Returns:

The const variant with the result.

Unnamed Group

template<typename TFunction>
static CConstVariant BinaryOperation(const CConstVariant &rvarOperand1, const CConstVariant &rvarOperand2, TFunction tOperation)

Do binary operation. The first version allows the operation on any arithmetic type. The second version works for integral operation only.

Template Parameters:

TFunction – The function type that should do the operation. The function uses the prototype:

CConstVariant(auto tOperand1, auto tOperand2); 

Parameters:

• rvarOperand1 – [in] The first operand.

• rvarOperand2 – [in] The second operand.

• tOperation – [in] The function that is used for the operation.

Returns:

The const variant with the result.

template<typename TFunction>
static CConstVariant BinaryOperationIntegral(const CConstVariant &rvarOperand1, const CConstVariant &rvarOperand2, TFunction tOperation)

Do binary operation. The first version allows the operation on any arithmetic type. The second version works for integral operation only.

Template Parameters:

TFunction – The function type that should do the operation. The function uses the prototype:

CConstVariant(auto tOperand1, auto tOperand2); 

Parameters:

• rvarOperand1 – [in] The first operand.

• rvarOperand2 – [in] The second operand.

• tOperation – [in] The function that is used for the operation.

Returns:

The const variant with the result.

Public Types

enum ETypeMapping

Type to index mapping.

Remark

’char’ is represented by ‘int8_t’. ‘char16_t’ is represented by ‘uint16_t’. ‘char32_t’ is represented by ‘int32_t’. ‘wchar_t’ is either represented by ‘uint16_t’ or by ‘uint32_t’. ASCII and UTF-8 strings are represented by ‘std::string’.

Values:

enumerator type_bool

enumerator type_int8_t

enumerator type_uint8_t

enumerator type_int16_t

enumerator type_uint16_t

enumerator type_int32_t

enumerator type_uint32_t

enumerator type_int64_t

enumerator type_uint64_t

enumerator type_fixed

enumerator type_float

enumerator type_double

enumerator type_long_double

enumerator type_string

enumerator type_u16string

enumerator type_u32string

enumerator type_wstring

Public Functions

CConstVariant() = default

Default constructor.

CConstVariant(const CConstVariant &rvar)

Copy constructor.

Parameters:

rvar – [in] Reference to the const variant to copy from.

CConstVariant(CConstVariant &&rvar) noexcept

Move constructor is not available.

Parameters:

rvar – [in] Reference to the const variant to move from.

CConstVariant(bool bValue)

Assignment constructor.

Parameters:

bValue – [in] Value to assign.

CConstVariant(int8_t iValue)

Assignment constructor.

Parameters:

iValue – [in] Value to assign.

CConstVariant(uint8_t uiValue)

Assignment constructor.

Parameters:

uiValue – [in] Value to assign.

CConstVariant(int16_t iValue)

Assignment constructor.

Parameters:

iValue – [in] Value to assign.

CConstVariant(uint16_t uiValue)

Assignment constructor.

Parameters:

uiValue – [in] Value to assign.

CConstVariant(int32_t iValue)

Assignment constructor.

Parameters:

iValue – [in] Value to assign.

CConstVariant(uint32_t uiValue)

Assignment constructor.

Parameters:

uiValue – [in] Value to assign.

CConstVariant(int64_t iValue)

Assignment constructor.

Parameters:

iValue – [in] Value to assign.

CConstVariant(uint64_t uiValue)

Assignment constructor.

Parameters:

uiValue – [in] Value to assign.

CConstVariant(fixed fixValue)

Assignment constructor.

Parameters:

fixValue – [in] Value to assign.

CConstVariant(float fValue)

Assignment constructor.

Parameters:

fValue – [in] Value to assign.

CConstVariant(double dValue)

Assignment constructor.

Parameters:

dValue – [in] Value to assign.

CConstVariant(long double ldValue)

Assignment constructor.

Parameters:

ldValue – [in] Value to assign.

CConstVariant(const std::string &rssValue)

Assignment constructor.

Parameters:

rssValue – [in] Reference to the string value to assign.

CConstVariant(const std::u16string &rssValue)

Assignment constructor.

Parameters:

rssValue – [in] Reference to the string value to assign.

CConstVariant(const std::u32string &rssValue)

Assignment constructor.

Parameters:

rssValue – [in] Reference to the string value to assign.

CConstVariant(const std::wstring &rssValue)

Assignment constructor.

Parameters:

rssValue – [in] Reference to the string value to assign.

CConstVariant &operator=(const CConstVariant &rvar)

Copy assignment operator.

Parameters:

rvar – [in] Reference to the const variant to copy from.

Returns:

Reference to the const variant instance.

CConstVariant &operator=(CConstVariant &&rvar) noexcept

Move operator is not available.

Parameters:

rvar – [in] Reference to the const variant to move from.

Returns:

Reference to the const variant instance.

template<typename TType>
CConstVariant &operator=(const TType &rtValue)

Assignment operator.

Template Parameters:

TType – Type of the value to assign.

Parameters:

rtValue – [in] Reference to the value to assign.

Returns:

Reference to the const variant instance.

template<typename TTargetType>
TTargetType Get() const

Get the value of the variant casted to the provided target type.

Throws:

Throws – exception when the value exceeds the boundaries of the target value or the types are incompatible.

Template Parameters:

TTargetType – The target type.

Returns:

The value casted to the target type.

std::string GetAsString() const

Get the value as string.

Returns:

Get the value as a string.

void Convert(size_t nRank)

Convert the variant to the type supplied.

Throws:

Throws – exception when the value exceeds the boundaries of the target value or the types are incompatible.

Parameters:

nRank – [in] The rank of the type to convert to.

template<typename TType>
void Convert()

Convert the variant to the type supplied.

Throws:

Throws – exception when the value exceeds the boundaries of the target value or the types are incompatible.

Template Parameters:

TType – The type to convert to.