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381 lines
8.8 KiB
Markdown
381 lines
8.8 KiB
Markdown
---
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title: "to_arithmetic"
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---
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{{< callout type="info">}}
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Header: `to_arithmetic.h`
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{{< /callout >}}
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Functions that will convert a text representation of an arithmetic type to a value.
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Converts from binary, octal, decimal and hex integrals, and decimal floating point types.
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Supports conversion from `char`, `wchar_t`, `char8_t`, `char16_t`, and `char32_t` strings.
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The numeric strings must not contain leading or trailing non-numeric characters. It is the responsibility of the user to select the valid character range.
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Integral types may be `constexpr`.
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## to_arithmetic_status
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An ETL enum type that defines the following enumeration values.
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The are the values that may be set as the error code in to_arithmetic_result.
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```cpp
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Valid
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Invalid_Radix
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Invalid_Format
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Invalid_Float
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Signed_To_Unsigned
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Overflow
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```
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## to_arithmetic_result
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The result type returned from `etl::to_arithmetic`.
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```cpp
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template <typename TValue>
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to_arithmetic_result
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```
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**Types**
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```cpp
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value_type TValue
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error_type etl::to_arithmetic_status
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unexpected_type etl::unexpected<etl::to_arithmetic_status>
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```
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---
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```cpp
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ETL_CONSTEXPR14
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to_arithmetic_result()
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```
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Default constructor.
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---
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```cpp
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ETL_CONSTEXPR14
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to_arithmetic_result(const to_arithmetic_result& other)
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```
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Copy constructor.
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---
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```cpp
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ETL_NODISCARD
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ETL_CONSTEXPR14
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bool has_value() const
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```
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Returns `true` if the result has a valid value.
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If `false` then the value is undefined.
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---
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```cpp
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ETL_NODISCARD
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ETL_CONSTEXPR14
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operator bool() const
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```
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Returns `true` if the result has a valid value.
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If `false` then the value is undefined.
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---
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```cpp
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ETL_NODISCARD
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ETL_CONSTEXPR14
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value_type value() const
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```
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Returns the value, if valid.
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Otherwise undefined.
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---
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```cpp
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ETL_NODISCARD
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ETL_CONSTEXPR14
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operator value_type() const
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```
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Returns the value, if valid.
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Otherwise undefined.
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---
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```cpp
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ETL_NODISCARD
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ETL_CONSTEXPR14
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error_type error() const
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```
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Returns the conversion status.
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One of the following:-
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```cpp
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Valid
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Invalid_Radix
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Invalid_Format
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Invalid_Float
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Signed_To_Unsigned
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Overflow
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```
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---
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```cpp
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ETL_CONSTEXPR14
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to_arithmetic_result& operator =(value_type value)
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```
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Assign from a value_type.
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---
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```cpp
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ETL_CONSTEXPR14
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to_arithmetic_result& operator =(unexpected_type status)
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```
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Assign from an unexpected_type.
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---
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## to_arithmetic
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Convert a string to an integral or floating point value.
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Supports:
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`etl::string_view` (`etl::basic_string_view<TChar>`)
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const pointer (to `char`, `wchar_t`, `char8_t`, `char16_t`, `char32_t`) + length
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`etl::string`, `etl::wstring`, `etl::u8string`, `etl::u16string`, or `etl::u32string`.
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```cpp
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template <typename TValue, typename TChar>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::to_arithmetic_result<TValue> to_arithmetic(const etl::basic_string_view<TChar>& view)
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```
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Text to integral or floating point from view and default decimal radix.
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---
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```cpp
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template <typename TValue, typename TChar>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::to_arithmetic_result<TValue> to_arithmetic(etl::basic_string_view<TChar> view,
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const etl::radix::value_type radix)
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```
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Text to integral from view and radix value type.
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radix may be one of the following:-
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```cpp
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etl::radix::binary
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etl::radix::octal
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etl::radix::decimal
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etl::radix::hex
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```
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---
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```cpp
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::to_arithmetic_result<TValue> to_arithmetic(const etl::basic_string_view<TChar>& view,
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const etl::private_basic_format_spec::base_spec& spec)
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```
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Text to integral from view and radix format spec.
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spec may be one of the following:-
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```cpp
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etl::bin
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etl::oct
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etl::dec
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etl::hex
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```
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---
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```cpp
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template <typename TValue, typename TChar>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::to_arithmetic_result<TValue> to_arithmetic(const TChar* cp,
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size_t length)
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```
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Text to integral or floating point from pointer, length and default decimal radix.
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---
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```cpp
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template <typename TValue, typename TChar>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::to_arithmetic_result<TValue> to_arithmetic(const TChar* cp,
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size_t length,
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const etl::radix::value_type radix)
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```
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Text to integral from pointer, length and radix value type.
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radix may be one of the following:-
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```cpp
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etl::radix::binary
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etl::radix::octal
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etl::radix::decimal
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etl::radix::hex
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```
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---
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```cpp
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template <typename TValue, typename TChar>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::to_arithmetic_result<TValue> to_arithmetic(const TChar* cp,
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size_t length,
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const etl::private_basic_format_spec::base_spec& spec)
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```
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Text to integral from pointer, length and radix format spec.
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spec may be one of the following:-
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```cpp
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etl::bin
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etl::oct
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etl::dec
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etl::hex
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```
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---
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```cpp
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template <typename TValue, typename TChar>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::to_arithmetic_result<TValue> to_arithmetic(const etl::ibasic_string<TChar>& str)
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```
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Text to integral or floating point from string and default decimal radix.
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---
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```cpp
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template <typename TValue, typename TChar>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::to_arithmetic_result<TValue> to_arithmetic(const etl::ibasic_string<TChar>& str,
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const etl::radix::value_type radix)
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```
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Text to integral from string and radix value type.
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radix may be one of the following:-
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```cpp
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etl::radix::binary
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etl::radix::octal
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etl::radix::decimal
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etl::radix::hex
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```
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---
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```cpp
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template <typename TValue, typename TChar>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::to_arithmetic_result<TValue> to_arithmetic(const etl::ibasic_string<TChar>& str,
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const etl::private_basic_format_spec::base_spec& spec)
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```
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Text to integral from string and radix format spec.
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spec may be one of the following:-
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```cpp
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etl::bin
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etl::oct
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etl::dec
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etl::hex
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```
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## Non-member functions
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```cpp
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template <typename T>
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ETL_CONSTEXPR14 bool operator ==(const etl::to_arithmetic_result<T>& lhs,
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const etl::to_arithmetic_result<T>& rhs)
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```
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Equality test for etl::to_arithmetic_result
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---
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```cpp
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template <typename T, typename U>
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ETL_CONSTEXPR14 bool operator ==(const etl::to_arithmetic_result<T>& lhs,
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const U& rhs)
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```
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Equality test for etl::to_arithmetic_result
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---
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```cpp
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template <typename T, typename U>
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ETL_CONSTEXPR14 bool operator ==(const T& lhs,
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const etl::to_arithmetic_result<U>& rhs)
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```
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Equality test for etl::to_arithmetic_result
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---
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```cpp
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template <typename T>
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ETL_CONSTEXPR14 bool operator !=(const etl::to_arithmetic_result<T>& lhs,
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const etl::to_arithmetic_result<T>& rhs)
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```
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Inequality test for etl::to_arithmetic_result
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---
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```cpp
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template <typename T, typename U>
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ETL_CONSTEXPR14 bool operator !=(const etl::to_arithmetic_result<T>& lhs,
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const U& rhs)
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```
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Inequality test for etl::to_arithmetic_result
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---
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```cpp
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template <typename T, typename U>
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ETL_CONSTEXPR14 bool operator !=(const T& lhs,
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const etl::to_arithmetic_result<T>& rhs)
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```
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Inequality test for etl::to_arithmetic_result
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## Examples
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**Valid conversions**
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```cpp
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const char* BinaryText("1010011");
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const etl::string<3> OctalText("123");
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const etl::string<4> DecimalText(" 83 ");
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const etl::string<2> HexText("85");
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const etl::string<2> FloatText("-123e5");
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// From char pointer to binary text. Format spec radix.
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int v1 = etl::to_arithmetic<int>(BinaryText, strlen(BinaryText), etl::bin);
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// From char pointer from octal text string. Radix spec value.
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int v2 = etl::to_arithmetic<int>(OctalText.c_str(), OctalText.size(), etl::radix::octal);
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// From view of decimal text string. Default base 10 radix.
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etl::string_view view(DecimalText.data() + 1, DecimalText.data() + 3);
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int v3 = etl::to_arithmetic<int>(view);
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// From hex string. Base 16 radix.
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int v4 = etl::to_arithmetic<int>(HexText, 16);
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```
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---
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**Invalid conversions**
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```cpp
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const etl::string<10> Text1("abcd");
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const etl::string<10> Text2(" 83 ");
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const etl::string<10> Text3("-83");
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const etl::string<10> Text4("4294967296");
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const etl::string<10> Text5("1.23E10000");
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etl::to_arithmetic_result result;
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result = etl::to_arithmetic<int32_t>(Text1, 5); // etl::to_arithmetic_status::Invalid_Radix
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result = etl::to_arithmetic<int32_t>(Text1); // etl::to_arithmetic_status::Invalid_Format
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result = etl::to_arithmetic<int32_t>(Text2); // etl::to_arithmetic_status::Invalid_Format
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result = etl::to_arithmetic<uint32_t>(Text3); // etl::to_arithmetic_status::Signed_To_Unsigned
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result = etl::to_arithmetic<int32_t>(Text4); // etl::to_arithmetic_status::Overflow
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result = etl::to_arithmetic<float>(Text5); // etl::to_arithmetic_status::Overflow
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```
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