//! Configuration options for parsing floats.

//!

//! This enables extensive control over how the float is parsed, from

//! control characters like the decimal point and the valid non-finite

//! float representations.

//!

//! # Examples

//!

//! For example, to parse a European-style float:

//!

//! ```rust

//! use lexical_parse_float::{FromLexicalWithOptions, Options};

//! use lexical_parse_float::format::STANDARD;

//!

//! const OPTIONS: Options = Options::builder()

//!     .decimal_point(b',')

//!     .build_strict();

//! let value = "1,2345e300";

//! let result = f64::from_lexical_with_options::<STANDARD>(value.as_bytes(), &OPTIONS);

//! assert_eq!(result, Ok(1.2345e300));

//! ```

//!

//! # Pre-Defined Formats

//!

//! These are the pre-defined formats for parsing numbers from various

//! programming, markup, and data languages.

//!

//! - [`STANDARD`]: Standard number format.

//! - [`DECIMAL_COMMA`]: Numerical format with a decimal comma.

//! - [`HEX_FLOAT`]: Numerical format for hexadecimal floats, which use a `p`

//!   exponent.

//! - [`RUST_LITERAL`]: Number format for a [`Rust`] literal floating-point

//!   number.

//! - [`PYTHON_LITERAL`]: Number format for a [`Python`] literal floating-point

//!   number.

//! - [`CXX_LITERAL`]: Number format for a [`C++`] literal floating-point

//!   number.

//! - [`C_LITERAL`]: Number format for a [`C`] literal floating-point number.

//! - [`RUBY_LITERAL`]: Number format for a [`Ruby`] literal floating-point

//!   number.

//! - [`RUBY_STRING`]: Number format to parse a [`Ruby`] float from string.

//! - [`SWIFT_LITERAL`]: Number format for a [`Swift`] literal floating-point

//!   number.

//! - [`GO_LITERAL`]: Number format for a [`Golang`] literal floating-point

//!   number.

//! - [`HASKELL_LITERAL`]: Number format for a [`Haskell`] literal

//!   floating-point number.

//! - [`HASKELL_STRING`]: Number format to parse a [`Haskell`] float from

//!   string.

//! - [`JAVASCRIPT_LITERAL`]: Number format for a [`Javascript`] literal

//!   floating-point number.

//! - [`JAVASCRIPT_STRING`]: Number format to parse a [`Javascript`] float from

//!   string.

//! - [`PERL_LITERAL`]: Number format for a [`Perl`] literal floating-point

//!   number.

//! - [`PHP_LITERAL`]: Number format for a [`PHP`] literal floating-point

//!   number.

//! - [`JAVA_LITERAL`]: Number format for a [`Java`] literal floating-point

//!   number.

//! - [`JAVA_STRING`]: Number format to parse a [`Java`] float from string.

//! - [`R_LITERAL`]: Number format for an [`R`] literal floating-point number.

//! - [`KOTLIN_LITERAL`]: Number format for a [`Kotlin`] literal floating-point

//!   number.

//! - [`KOTLIN_STRING`]: Number format to parse a [`Kotlin`] float from string.

//! - [`JULIA_LITERAL`]: Number format for a [`Julia`] literal floating-point

//!   number.

//! - [`CSHARP_LITERAL`]: Number format for a [`C#`] literal floating-point

//!   number.

//! - [`CSHARP_STRING`]: Number format to parse a [`C#`] float from string.

//! - [`KAWA_LITERAL`]: Number format for a [`Kawa`] literal floating-point

//!   number.

//! - [`KAWA_STRING`]: Number format to parse a [`Kawa`] float from string.

//! - [`GAMBITC_LITERAL`]: Number format for a [`Gambit-C`] literal

//!   floating-point number.

//! - [`GAMBITC_STRING`]: Number format to parse a [`Gambit-C`] float from

//!   string.

//! - [`GUILE_LITERAL`]: Number format for a [`Guile`] literal floating-point

//!   number.

//! - [`GUILE_STRING`]: Number format to parse a [`Guile`] float from string.

//! - [`CLOJURE_LITERAL`]: Number format for a [`Clojure`] literal

//!   floating-point number.

//! - [`CLOJURE_STRING`]: Number format to parse a [`Clojure`] float from

//!   string.

//! - [`ERLANG_LITERAL`]: Number format for an [`Erlang`] literal floating-point

//!   number.

//! - [`ERLANG_STRING`]: Number format to parse an [`Erlang`] float from string.

//! - [`ELM_LITERAL`]: Number format for an [`Elm`] literal floating-point

//!   number.

//! - [`ELM_STRING`]: Number format to parse an [`Elm`] float from string.

//! - [`SCALA_LITERAL`]: Number format for a [`Scala`] literal floating-point

//!   number.

//! - [`SCALA_STRING`]: Number format to parse a [`Scala`] float from string.

//! - [`ELIXIR_LITERAL`]: Number format for an [`Elixir`] literal floating-point

//!   number.

//! - [`ELIXIR_STRING`]: Number format to parse an [`Elixir`] float from string.

//! - [`FORTRAN_LITERAL`]: Number format for a [`FORTRAN`] literal

//!   floating-point number.

//! - [`D_LITERAL`]: Number format for a [`D`] literal floating-point number.

//! - [`COFFEESCRIPT_LITERAL`]: Number format for a [`Coffeescript`] literal

//!   floating-point number.

//! - [`COFFEESCRIPT_STRING`]: Number format to parse a [`Coffeescript`] float

//!   from string.

//! - [`COBOL_LITERAL`]: Number format for a [`COBOL`] literal floating-point

//!   number.

//! - [`COBOL_STRING`]: Number format to parse a [`COBOL`] float from string.

//! - [`FSHARP_LITERAL`]: Number format for an [`F#`] literal floating-point

//!   number.

//! - [`VB_LITERAL`]: Number format for a [`Visual Basic`] literal

//!   floating-point number.

//! - [`VB_STRING`]: Number format to parse a [`Visual Basic`] float from

//!   string.

//! - [`OCAML_LITERAL`]: Number format for an [`OCaml`] literal floating-point

//!   number.

//! - [`OBJECTIVEC_LITERAL`]: Number format for an [`Objective-C`] literal

//!   floating-point number.

//! - [`OBJECTIVEC_STRING`]: Number format to parse an [`Objective-C`] float

//!   from string.

//! - [`REASONML_LITERAL`]: Number format for an [`ReasonML`] literal

//!   floating-point number.

//! - [`MATLAB_LITERAL`]: Number format for a [`MATLAB`] literal floating-point

//!   number.

//! - [`ZIG_LITERAL`]: Number format for a [`Zig`] literal floating-point

//!   number.

//! - [`SAGE_LITERAL`]: Number format for a [`Sage`] literal floating-point

//!   number.

//! - [`JSON`]: Number format for a [`JSON`][`JSON-REF`] literal floating-point

//!   number.

//! - [`TOML`]: Number format for a [`TOML`][`TOML-REF`] literal floating-point

//!   number.

//! - [`YAML`]: Number format for a [`YAML`][`YAML-REF`] literal floating-point

//!   number.

//! - [`XML`]: Number format for an [`XML`][`XML-REF`] literal floating-point

//!   number.

//! - [`SQLITE`]: Number format for a [`SQLite`] literal floating-point number.

//! - [`POSTGRESQL`]: Number format for a [`PostgreSQL`] literal floating-point

//!   number.

//! - [`MYSQL`]: Number format for a [`MySQL`] literal floating-point number.

//! - [`MONGODB`]: Number format for a [`MongoDB`] literal floating-point

//!   number.

//!

//! <!-- References -->

//!

//! [`Rust`]: https://www.rust-lang.org/

//! [`Python`]: https://www.python.org/

//! [`C++`]: https://en.cppreference.com/w/

//! [`C`]: https://en.cppreference.com/w/c

//! [`Ruby`]: https://www.ruby-lang.org/en/

//! [`Swift`]: https://developer.apple.com/swift/

//! [`Golang`]: https://go.dev/

//! [`Haskell`]: https://www.haskell.org/

//! [`Javascript`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript

//! [`Perl`]: https://www.perl.org/

//! [`PHP`]: https://www.php.net/

//! [`Java`]: https://www.java.com/en/

//! [`R`]: https://www.r-project.org/

//! [`Kotlin`]: https://kotlinlang.org/

//! [`Julia`]: https://julialang.org/

//! [`C#`]: https://learn.microsoft.com/en-us/dotnet/csharp/

//! [`Kawa`]: https://www.gnu.org/software/kawa/

//! [`Gambit-C`]: https://gambitscheme.org/

//! [`Guile`]: https://www.gnu.org/software/guile/

//! [`Clojure`]: https://clojure.org/

//! [`Erlang`]: https://www.erlang.org/

//! [`Elm`]: https://elm-lang.org/

//! [`Scala`]: https://www.scala-lang.org/

//! [`Elixir`]: https://elixir-lang.org/

//! [`FORTRAN`]: https://fortran-lang.org/

//! [`D`]: https://dlang.org/

//! [`Coffeescript`]: https://coffeescript.org/

//! [`Cobol`]: https://www.ibm.com/think/topics/cobol

//! [`F#`]: https://fsharp.org/

//! [`Visual Basic`]: https://learn.microsoft.com/en-us/dotnet/visual-basic/

//! [`OCaml`]: https://ocaml.org/

//! [`Objective-C`]: https://en.wikipedia.org/wiki/Objective-C

//! [`ReasonML`]: https://reasonml.github.io/

//! [`Matlab`]: https://www.mathworks.com/products/matlab.html

//! [`Zig`]: https://ziglang.org/

//! [`Sage`]: https://www.sagemath.org/

//! [`JSON-REF`]: https://www.json.org/json-en.html

//! [`TOML-REF`]: https://toml.io/en/

//! [`YAML-REF`]: https://yaml.org/

//! [`XML-REF`]: https://en.wikipedia.org/wiki/XML

//! [`SQLite`]: https://www.sqlite.org/

//! [`PostgreSQL`]: https://www.postgresql.org/

//! [`MySQL`]: https://www.mysql.com/

//! [`MongoDB`]: https://www.mongodb.com/

#![allow(clippy::must_use_candidate)]

use lexical_util::ascii::{is_valid_ascii, is_valid_letter_slice};

use lexical_util::error::Error;

use lexical_util::options::{self, ParseOptions};

use lexical_util::result::Result;

/// Maximum length for a special string.

pub const MAX_SPECIAL_STRING_LENGTH: usize = 50;

/// Builder for [`Options`].

///

/// This enables extensive control over how the float is parsed, from

/// control characters like the decimal point and the valid non-finite

/// float representations.

///

/// # Examples

///

/// ```rust

/// use lexical_parse_float::{FromLexicalWithOptions, Options};

/// use lexical_parse_float::format::STANDARD;

///

/// const OPTIONS: Options = Options::builder()

///     .decimal_point(b',')

///     .build_strict();

/// let value = "1,2345e300";

/// let result = f64::from_lexical_with_options::<STANDARD>(value.as_bytes(), &OPTIONS);

/// assert_eq!(result, Ok(1.2345e300));

/// ```

#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]

pub struct OptionsBuilder {

    /// Disable the use of arbitrary-precision arithmetic, and always

    /// return the results from the fast or intermediate path algorithms.

    lossy: bool,

    /// Character to designate the exponent component of a float.

    exponent: u8,

    /// Character to separate the integer from the fraction components.

    decimal_point: u8,

    /// String representation of Not A Number, aka `NaN`.

    nan_string: Option<&'static [u8]>,

    /// Short string representation of `Infinity`.

    inf_string: Option<&'static [u8]>,

    /// Long string representation of `Infinity`.

    infinity_string: Option<&'static [u8]>,

}

impl OptionsBuilder {

    /// Create new options builder with default options.

    #[inline(always)]

    pub const fn new() -> Self {

        Self {

            lossy: false,

            exponent: b'e',

            decimal_point: b'.',

            nan_string: Some(b"NaN"),

            inf_string: Some(b"inf"),

            infinity_string: Some(b"infinity"),

        }

    }

    // GETTERS

    /// Get if we disable the use of arbitrary-precision arithmetic.

    ///

    /// Lossy algorithms never use the fallback, slow algorithm. Defaults to

    /// [`false`].

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// assert_eq!(Options::builder().get_lossy(), false);

    /// ```

    #[inline(always)]

    pub const fn get_lossy(&self) -> bool {

        self.lossy

    }

    /// Get the character to designate the exponent component of a float.

    ///

    /// Any non-control character is valid, but `\t` to `\r` are also valid.

    /// The full range is `[0x09, 0x0D]` and `[0x20, 0x7F]`. Defaults to `e`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// assert_eq!(Options::builder().get_exponent(), b'e');

    /// ```

    #[inline(always)]

    pub const fn get_exponent(&self) -> u8 {

        self.exponent

    }

    /// Get the character to separate the integer from the fraction components.

    ///

    /// Any non-control character is valid, but `\t` to `\r` are also valid.

    /// The full range is `[0x09, 0x0D]` and `[0x20, 0x7F]`. Defaults to `.`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// assert_eq!(Options::builder().get_decimal_point(), b'.');

    /// ```

    #[inline(always)]

    pub const fn get_decimal_point(&self) -> u8 {

        self.decimal_point

    }

    /// Get the string representation for `NaN`.

    ///

    /// The first character must start with `N` or `n` and all characters must

    /// be valid ASCII letters (`A-Z` or `a-z`). Defaults to `NaN`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::Options;

    ///

    /// let builder = Options::builder();

    /// assert_eq!(builder.get_nan_string(), Some("NaN".as_bytes()));

    /// ```

    #[inline(always)]

    pub const fn get_nan_string(&self) -> Option<&'static [u8]> {

        self.nan_string

    }

    /// Get the short string representation for `Infinity`.

    ///

    /// The first character must start with `I` or `i` and all characters must

    /// be valid ASCII letters (`A-Z` or `a-z`). Defaults to `inf`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::Options;

    ///

    /// let builder = Options::builder();

    /// assert_eq!(builder.get_inf_string(), Some("inf".as_bytes()));

    /// ```

    #[inline(always)]

    pub const fn get_inf_string(&self) -> Option<&'static [u8]> {

        self.inf_string

    }

    /// Get the long string representation for `Infinity`.

    ///

    /// The first character must start with `I` or `i` and all characters must

    /// be valid ASCII letters (`A-Z` or `a-z`). Defaults to `infinity`.

    ///

    /// [`get_inf_string`]: Self::get_inf_string

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::Options;

    ///

    /// let builder = Options::builder();

    /// assert_eq!(builder.get_infinity_string(), Some("infinity".as_bytes()));

    /// ```

    #[inline(always)]

    pub const fn get_infinity_string(&self) -> Option<&'static [u8]> {

        self.infinity_string

    }

    // SETTERS

    /// Set if we disable the use of arbitrary-precision arithmetic.

    ///

    /// Lossy algorithms never use the fallback, slow algorithm. Defaults to

    /// [`false`].

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// const OPTIONS: Options = Options::builder()

    ///     .lossy(true)

    ///     .build_strict();

    /// assert_eq!(OPTIONS.lossy(), true);

    /// ```

    #[must_use]

    #[inline(always)]

    pub const fn lossy(mut self, lossy: bool) -> Self {

        self.lossy = lossy;

        self

    }

    /// Set the character to designate the exponent component of a float.

    ///

    /// Any non-control character is valid, but `\t` to `\r` are also valid.

    /// The full range is `[0x09, 0x0D]` and `[0x20, 0x7F]`. Defaults to `e`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// const OPTIONS: Options = Options::builder()

    ///     .exponent(b'^')

    ///     .build_strict();

    /// assert_eq!(OPTIONS.exponent(), b'^');

    /// ```

    #[must_use]

    #[inline(always)]

    pub const fn exponent(mut self, exponent: u8) -> Self {

        self.exponent = exponent;

        self

    }

    /// Set the character to separate the integer from the fraction components.

    ///

    /// Any non-control character is valid, but `\t` to `\r` are also valid.

    /// The full range is `[0x09, 0x0D]` and `[0x20, 0x7F]`. Defaults to `.`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// const OPTIONS: Options = Options::builder()

    ///     .exponent(b',')

    ///     .build_strict();

    /// assert_eq!(OPTIONS.exponent(), b',');

    /// ```

    #[must_use]

    #[inline(always)]

    pub const fn decimal_point(mut self, decimal_point: u8) -> Self {

        self.decimal_point = decimal_point;

        self

    }

    /// Set the string representation for `NaN`.

    ///

    /// The first character must start with `N` or `n` and all characters must

    /// be valid ASCII letters (`A-Z` or `a-z`). If set to `None`, then parsing

    /// [`NaN`][f64::NAN] returns an error. Defaults to `NaN`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::Options;

    ///

    /// const OPTIONS: Options = Options::builder()

    ///     .nan_string(Some(b"nan"))

    ///     .build_strict();

    /// assert_eq!(OPTIONS.nan_string(), Some(b"nan".as_ref()));

    /// ```

    ///

    /// Panics

    ///

    /// Setting a value with more than 50 elements will panic at runtime. You

    /// should always build the format using [`build_strict`] or checking

    /// [`is_valid`] prior to using the format, to avoid unexpected panics.

    ///

    /// [`build_strict`]: Self::build_strict

    /// [`is_valid`]: Self::is_valid

    #[must_use]

    #[inline(always)]

    pub const fn nan_string(mut self, nan_string: Option<&'static [u8]>) -> Self {

        self.nan_string = nan_string;

        self

    }

    /// Set the short string representation for `Infinity`.

    ///

    /// The first character must start with `I` or `i` and all characters must

    /// be valid ASCII letters (`A-Z` or `a-z`). If set to `None`, then parsing

    /// [`Infinity`][f64::INFINITY] returns an error. Defaults to `inf`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::Options;

    ///

    /// const OPTIONS: Options = Options::builder()

    ///     .inf_string(Some(b"Infinity"))

    ///     .build_strict();

    /// assert_eq!(OPTIONS.inf_string(), Some(b"Infinity".as_ref()));

    /// ```

    ///

    /// Panics

    ///

    /// Setting a value with more than 50 elements or one that is longer than

    /// [`infinity_string`] will panic at runtime. You should always build

    /// the format using [`build_strict`] or checking [`is_valid`] prior to

    /// using the format, to avoid unexpected panics.

    ///

    /// [`infinity_string`]: Self::infinity_string

    /// [`build_strict`]: Self::build_strict

    /// [`is_valid`]: Self::is_valid

    #[must_use]

    #[inline(always)]

    pub const fn inf_string(mut self, inf_string: Option<&'static [u8]>) -> Self {

        self.inf_string = inf_string;

        self

    }

    /// Set the long string representation for `Infinity`.

    ///

    /// The first character must start with `I` or `i` and all characters must

    /// be valid ASCII letters (`A-Z` or `a-z`). If set to `None`, then parsing

    /// [`Infinity`][f64::INFINITY] returns an error. Defaults to `infinity`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::Options;

    ///

    /// const OPTIONS: Options = Options::builder()

    ///     .infinity_string(Some(b"Infinity"))

    ///     .build_strict();

    /// assert_eq!(OPTIONS.infinity_string(), Some(b"Infinity".as_ref()));

    /// ```

    ///

    /// Panics

    ///

    /// Setting a value with more than 50 elements or one that is shorter than

    /// [`inf_string`] will panic at runtime. You should always build the format

    /// using [`build_strict`] or checking [`is_valid`] prior to

    /// using the format, to avoid unexpected panics.

    ///

    /// [`inf_string`]: Self::inf_string

    /// [`build_strict`]: Self::build_strict

    /// [`is_valid`]: Self::is_valid

    #[must_use]

    #[inline(always)]

    pub const fn infinity_string(mut self, infinity_string: Option<&'static [u8]>) -> Self {

        self.infinity_string = infinity_string;

        self

    }

    // BUILDERS

    /// Determine if [`nan_string`] is valid.

    ///

    /// [`nan_string`]: Self::nan_string

    #[doc(hidden)]

    #[inline(always)]

    #[allow(clippy::if_same_then_else, clippy::needless_bool)] // reason = "more idiomatic"

    pub const fn nan_str_is_valid(&self) -> bool {

        if self.nan_string.is_none() {

            return true;

        }

        let nan = unwrap_str(self.nan_string);

        let length = nan.len();

        if length == 0 || length > MAX_SPECIAL_STRING_LENGTH {

            false

        } else if !matches!(nan[0], b'N' | b'n') {

            false

        } else if !is_valid_letter_slice(nan) {

            false

        } else {

            true

        }

    }

    /// Determine if [`inf_string`] is valid.

    ///

    /// [`inf_string`]: Self::inf_string

    #[doc(hidden)]

    #[inline(always)]

    #[allow(clippy::if_same_then_else, clippy::needless_bool)] // reason = "more idiomatic"

    pub const fn inf_str_is_valid(&self) -> bool {

        if self.infinity_string.is_none() && self.inf_string.is_some() {

            return false;

        } else if self.inf_string.is_none() {

            return true;

        }

        let inf = unwrap_str(self.inf_string);

        let length = inf.len();

        let infinity = unwrap_str(self.infinity_string);

        if length == 0 || length > MAX_SPECIAL_STRING_LENGTH {

            false

        } else if !matches!(inf[0], b'I' | b'i') {

            false

        } else if length > infinity.len() {

            false

        } else if !is_valid_letter_slice(inf) {

            false

        } else {

            true

        }

    }

    /// Determine if [`infinity_string`] is valid.

    ///

    /// [`infinity_string`]: Self::infinity_string

    #[doc(hidden)]

    #[inline(always)]

    #[allow(clippy::if_same_then_else, clippy::needless_bool)] // reason = "more idiomatic"

    pub const fn infinity_string_is_valid(&self) -> bool {

        if self.infinity_string.is_none() && self.inf_string.is_some() {

            return false;

        } else if self.infinity_string.is_none() {

            return true;

        }

        let inf = unwrap_str(self.inf_string);

        let infinity = unwrap_str(self.infinity_string);

        let length = infinity.len();

        if length == 0 || length > MAX_SPECIAL_STRING_LENGTH {

            false

        } else if !matches!(infinity[0], b'I' | b'i') {

            false

        } else if length < inf.len() {

            false

        } else if !is_valid_letter_slice(infinity) {

            false

        } else {

            true

        }

    }

    /// Check if the builder state is valid.

    #[inline(always)]

    #[allow(clippy::if_same_then_else, clippy::needless_bool)] // reason = "more idiomatic"

    pub const fn is_valid(&self) -> bool {

        if !is_valid_ascii(self.exponent) {

            false

        } else if !is_valid_ascii(self.decimal_point) {

            false

        } else if !self.nan_str_is_valid() {

            false

        } else if !self.inf_str_is_valid() {

            false

        } else if !self.infinity_string_is_valid() {

            false

        } else {

            true

        }

    }

    /// Build the [`Options`] struct without validation.

    ///

    /// # Panics

    ///

    /// This is completely safe, however, misusing this, especially

    /// the [`nan_string`], [`inf_string`], and [`infinity_string`] could

    /// panic at runtime. Always use [`is_valid`] prior to using the built

    /// options.

    ///

    /// [`inf_string`]: Self::inf_string

    /// [`nan_string`]: Self::nan_string

    /// [`infinity_string`]: Self::infinity_string

    /// [`is_valid`]: Self::is_valid

    #[inline(always)]

    pub const fn build_unchecked(&self) -> Options {

        Options {

            lossy: self.lossy,

            exponent: self.exponent,

            decimal_point: self.decimal_point,

            nan_string: self.nan_string,

            inf_string: self.inf_string,

            infinity_string: self.infinity_string,

        }

    }

    /// Build the [`Options`] struct, panicking if the builder is invalid.

    ///

    /// # Panics

    ///

    /// If the built options are not valid. This should always

    /// be used within a const context to avoid panics at runtime.

    #[inline(always)]

    pub const fn build_strict(&self) -> Options {

        match self.build() {

            Ok(value) => value,

            Err(error) => core::panic!("{}", error.description()),

        }

    }

    /// Build the [`Options`] struct.

    ///

    /// # Errors

    ///

    /// If the NaN, Inf, or Infinity strings are too long or invalid

    /// digits/characters are provided for some numerical formats.

    #[inline(always)]

    #[allow(clippy::if_same_then_else)] // reason = "more idiomatic"

    pub const fn build(&self) -> Result<Options> {

        if !is_valid_ascii(self.exponent) {

            return Err(Error::InvalidExponentSymbol);

        } else if !is_valid_ascii(self.decimal_point) {

            return Err(Error::InvalidDecimalPoint);

        }

        if self.nan_string.is_some() {

            let nan = unwrap_str(self.nan_string);

            if nan.is_empty() || !matches!(nan[0], b'N' | b'n') {

                return Err(Error::InvalidNanString);

            } else if !is_valid_letter_slice(nan) {

                return Err(Error::InvalidNanString);

            } else if nan.len() > MAX_SPECIAL_STRING_LENGTH {

                return Err(Error::NanStringTooLong);

            }

        }

        if self.inf_string.is_some() && self.infinity_string.is_none() {

            return Err(Error::InfinityStringTooShort);

        }

        if self.inf_string.is_some() {

            let inf = unwrap_str(self.inf_string);

            if inf.is_empty() || !matches!(inf[0], b'I' | b'i') {

                return Err(Error::InvalidInfString);

            } else if !is_valid_letter_slice(inf) {

                return Err(Error::InvalidInfString);

            } else if inf.len() > MAX_SPECIAL_STRING_LENGTH {

                return Err(Error::InfStringTooLong);

            }

        }

        if self.infinity_string.is_some() {

            let inf = unwrap_str(self.inf_string);

            let infinity = unwrap_str(self.infinity_string);

            if infinity.is_empty() || !matches!(infinity[0], b'I' | b'i') {

                return Err(Error::InvalidInfinityString);

            } else if !is_valid_letter_slice(infinity) {

                return Err(Error::InvalidInfinityString);

            } else if infinity.len() > MAX_SPECIAL_STRING_LENGTH {

                return Err(Error::InfinityStringTooLong);

            } else if infinity.len() < inf.len() {

                return Err(Error::InfinityStringTooShort);

            }

        }

        Ok(self.build_unchecked())

    }

}

impl Default for OptionsBuilder {

    #[inline(always)]

    fn default() -> Self {

        Self::new()

    }

}

/// Options to customize parsing floats.

///

/// This enables extensive control over how the float is parsed, from

/// control characters like the decimal point and the valid non-finite

/// float representations.

///

/// # Examples

///

/// ```rust

/// use lexical_parse_float::{FromLexicalWithOptions, Options};

/// use lexical_parse_float::format::STANDARD;

///

/// const OPTIONS: Options = Options::builder()

///     .lossy(true)

///     .nan_string(Some(b"NaN"))

///     .inf_string(Some(b"Inf"))

///     .infinity_string(Some(b"Infinity"))

///     .build_strict();

///

/// let value = "1.2345e300";

/// let result = f64::from_lexical_with_options::<STANDARD>(value.as_bytes(), &OPTIONS);

/// assert_eq!(result, Ok(1.2345e300));

///

/// let value = "NaN";

/// let result = f64::from_lexical_with_options::<STANDARD>(value.as_bytes(), &OPTIONS);

/// assert_eq!(result.map(|x| x.is_nan()), Ok(true));

/// ```

#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]

pub struct Options {

    /// Disable the use of arbitrary-precision arithmetic, and always

    /// return the results from the fast or intermediate path algorithms.

    lossy: bool,

    /// Character to designate the exponent component of a float.

    exponent: u8,

    /// Character to separate the integer from the fraction components.

    decimal_point: u8,

    /// String representation of Not A Number, aka `NaN`.

    nan_string: Option<&'static [u8]>,

    /// Short string representation of `Infinity`.

    inf_string: Option<&'static [u8]>,

    /// Long string representation of `Infinity`.

    infinity_string: Option<&'static [u8]>,

}

impl Options {

    // CONSTRUCTORS

    /// Create options with default values.

    #[inline(always)]

    pub const fn new() -> Self {

        Self::builder().build_unchecked()

    }

    /// Create the default options for a given radix.

    ///

    /// This sets the exponent to `^` for any radix where `e`

    /// would be a valid digit.

    #[inline(always)]

    #[cfg(feature = "power-of-two")]

    pub const fn from_radix(radix: u8) -> Self {

        // Need to determine the correct exponent character ('e' or '^'),

        // since the default character is `e` normally, but this is a valid

        // digit for radix >= 15.

        let mut builder = Self::builder();

        if radix >= 15 {

            builder = builder.exponent(b'^');

        }

        builder.build_unchecked()

    }

    // GETTERS

    /// Check if the options state is valid.

    #[inline(always)]

    pub const fn is_valid(&self) -> bool {

        self.rebuild().is_valid()

    }

    /// Get if we disable the use of arbitrary-precision arithmetic.

    ///

    /// Lossy algorithms never use the fallback, slow algorithm. Defaults to

    /// [`false`].

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// assert_eq!(Options::new().lossy(), false);

    /// ```

    #[inline(always)]

    pub const fn lossy(&self) -> bool {

        self.lossy

    }

    /// Get the character to designate the exponent component of a float.

    ///

    /// Any non-control character is valid, but `\t` to `\r` are also valid.

    /// The full range is `[0x09, 0x0D]` and `[0x20, 0x7F]`. Defaults to `e`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// assert_eq!(Options::new().exponent(), b'e');

    /// ```

    #[inline(always)]

    pub const fn exponent(&self) -> u8 {

        self.exponent

    }

    /// Get the character to separate the integer from the fraction components.

    ///

    /// Any non-control character is valid, but `\t` to `\r` are also valid.

    /// The full range is `[0x09, 0x0D]` and `[0x20, 0x7F]`. Defaults to `.`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// assert_eq!(Options::new().decimal_point(), b'.');

    /// ```

    #[inline(always)]

    pub const fn decimal_point(&self) -> u8 {

        self.decimal_point

    }

    /// Get the string representation for `NaN`.

    ///

    /// The first character must start with `N` or `n` and all characters must

    /// be valid ASCII letters (`A-Z` or `a-z`). If set to `None`, then parsing

    /// [`NaN`][f64::NAN] returns an error. Defaults to `NaN`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// assert_eq!(Options::new().nan_string(), Some(b"NaN".as_ref()));

    /// ```

    #[inline(always)]

    pub const fn nan_string(&self) -> Option<&'static [u8]> {

        self.nan_string

    }

    /// Get the short string representation for `Infinity`.

    ///

    /// The first character must start with `I` or `i` and all characters must

    /// be valid ASCII letters (`A-Z` or `a-z`). If set to `None`, then parsing

    /// [`Infinity`][f64::INFINITY] returns an error. Defaults to `inf`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// assert_eq!(Options::new().inf_string(), Some(b"inf".as_ref()));

    /// ```

    #[inline(always)]

    pub const fn inf_string(&self) -> Option<&'static [u8]> {

        self.inf_string

    }

    /// Get the long string representation for `Infinity`.

    ///

    /// The first character must start with `I` or `i` and all characters must

    /// be valid ASCII letters (`A-Z` or `a-z`). If set to `None`, then parsing

    /// [`Infinity`][f64::INFINITY] returns an error. Defaults to `infinity`.

    ///

    /// # Examples

    ///

    /// ```rust

    /// use lexical_parse_float::options::Options;

    ///

    /// assert_eq!(Options::new().infinity_string(), Some(b"infinity".as_ref()));

    /// ```

    #[inline(always)]

    pub const fn infinity_string(&self) -> Option<&'static [u8]> {

        self.infinity_string

    }

    // SETTERS

    /// Set if we disable the use of arbitrary-precision arithmetic.

    #[inline(always)]

    #[deprecated = "Options should be treated as immutable, use `OptionsBuilder` instead. Will be removed in 2.0."]

    pub fn set_lossy(&mut self, lossy: bool) {

        self.lossy = lossy;

    }

    /// Set the character to designate the exponent component of a float.

    #[inline(always)]

    #[deprecated = "Options should be treated as immutable, use `OptionsBuilder` instead. Will be removed in 2.0."]

    pub fn set_exponent(&mut self, exponent: u8) {

        self.exponent = exponent;

    }

    /// Set the character to separate the integer from the fraction components.

    #[inline(always)]

    #[deprecated = "Options should be treated as immutable, use `OptionsBuilder` instead. Will be removed in 2.0."]

    pub fn set_decimal_point(&mut self, decimal_point: u8) {

        self.decimal_point = decimal_point;

    }

    /// Set the string representation for `NaN`.

    #[inline(always)]

    #[deprecated = "Options should be treated as immutable, use `OptionsBuilder` instead. Will be removed in 2.0."]

    pub fn set_nan_string(&mut self, nan_string: Option<&'static [u8]>) {

        self.nan_string = nan_string;

    }

    /// Set the short string representation for `Infinity`

    #[inline(always)]

    #[deprecated = "Options should be treated as immutable, use `OptionsBuilder` instead. Will be removed in 2.0."]

    pub fn set_inf_string(&mut self, inf_string: Option<&'static [u8]>) {

        self.inf_string = inf_string;

    }

    /// Set the long string representation for `Infinity`

    #[inline(always)]

    #[deprecated = "Options should be treated as immutable, use `OptionsBuilder` instead. Will be removed in 2.0."]

    pub fn set_infinity_string(&mut self, infinity_string: Option<&'static [u8]>) {

        self.infinity_string = infinity_string;

    }

    // BUILDERS

    /// Get [`OptionsBuilder`] as a static function.

    #[must_use]

    #[inline(always)]

    pub const fn builder() -> OptionsBuilder {

        OptionsBuilder::new()

    }

    /// Create [`OptionsBuilder`] using existing values.

    #[must_use]

    #[inline(always)]

    pub const fn rebuild(&self) -> OptionsBuilder {

        OptionsBuilder {

            lossy: self.lossy,

            exponent: self.exponent,

            decimal_point: self.decimal_point,

            nan_string: self.nan_string,

            inf_string: self.inf_string,

            infinity_string: self.infinity_string,

        }

    }

}

impl Default for Options {

    #[inline(always)]

    fn default() -> Self {

        Self::new()

    }

}

impl ParseOptions for Options {

    #[inline(always)]

    fn is_valid(&self) -> bool {

        Self::is_valid(self)

    }

}

/// Unwrap `Option` as a const fn.

#[inline(always)]

const fn unwrap_str(option: Option<&'static [u8]>) -> &'static [u8] {

    match option {

        Some(x) => x,

        None => &[],

    }

}

// PRE-DEFINED CONSTANTS

// ---------------------

// Only constants that differ from the standard version are included.

/// Standard number format.

#[rustfmt::skip]

pub const STANDARD: Options = Options::new();

/// Numerical format with a decimal comma.

/// This is the standard numerical format for most of the world.

#[rustfmt::skip]

pub const DECIMAL_COMMA: Options = Options::builder()

    .decimal_point(b',')

    .build_strict();

/// Numerical format for hexadecimal floats, which use a `p` exponent.

#[rustfmt::skip]

pub const HEX_FLOAT: Options = Options::builder()

    .exponent(b'p')

    .build_strict();

/// Numerical format where `^` is used as the exponent notation character.

/// This isn't very common, but is useful when `e` or `p` are valid digits.

#[rustfmt::skip]

pub const CARAT_EXPONENT: Options = Options::builder()

    .exponent(b'^')

    .build_strict();

/// Number format for a `Rust` literal floating-point number.

#[rustfmt::skip]

pub const RUST_LITERAL: Options = Options::builder()

    .nan_string(options::RUST_LITERAL)

    .inf_string(options::RUST_LITERAL)

    .infinity_string(options::RUST_LITERAL)

    .build_strict();

/// Number format for a `Python` literal floating-point number.

#[rustfmt::skip]

pub const PYTHON_LITERAL: Options = Options::builder()

    .nan_string(options::PYTHON_LITERAL)

    .inf_string(options::PYTHON_LITERAL)

    .infinity_string(options::PYTHON_LITERAL)

    .build_strict();

/// Number format for a `C++` literal floating-point number.

#[rustfmt::skip]

pub const CXX_LITERAL: Options = Options::builder()

    .nan_string(options::CXX_LITERAL_NAN)

    .inf_string(options::CXX_LITERAL_INF)

    .infinity_string(options::CXX_LITERAL_INFINITY)

    .build_strict();

/// Number format for a `C` literal floating-point number.

#[rustfmt::skip]