lexical_util/api.rs
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//! Implement string conversion routines in a single trait.
// NOTE:
// We use macros to define the traits, rather than implement here
// since we can't define traits for types when both are defined outside
// the current crate, including in workspaces.
// FROM LEXICAL
/// Define FromLexical trait.
#[macro_export]
#[cfg(feature = "parse")]
macro_rules! from_lexical {
() => {
/// Trait for numerical types that can be parsed from bytes.
pub trait FromLexical: lexical_util::num::Number {
/// Checked parser for a string-to-number conversion.
///
/// This method parses the entire string, returning an error if
/// any invalid digits are found during parsing. Returns a `Result`
/// containing either the parsed value, or an error containing
/// any errors that occurred during parsing.
///
/// * `bytes` - Slice containing a numeric string.
fn from_lexical(bytes: &[u8]) -> lexical_util::result::Result<Self>;
/// Checked parser for a string-to-number conversion.
///
/// This method parses until an invalid digit is found (or the end
/// of the string), returning the number of processed digits
/// and the parsed value until that point. Returns a `Result`
/// containing either the parsed value and the number of processed
/// digits, or an error containing any errors that occurred during
/// parsing.
///
/// * `bytes` - Slice containing a numeric string.
fn from_lexical_partial(bytes: &[u8]) -> lexical_util::result::Result<(Self, usize)>;
}
};
}
/// Define FromLexicalWithOptions trait.
#[macro_export]
#[cfg(feature = "parse")]
macro_rules! from_lexical_with_options {
() => {
/// Trait for numerical types that can be parsed from bytes with custom options.
///
/// The `Options` type specifies the configurable options to provide.
pub trait FromLexicalWithOptions: lexical_util::num::Number {
/// Custom formatting options for parsing a number.
type Options: lexical_util::options::ParseOptions;
/// Checked parser for a string-to-number conversion.
///
/// This method parses the entire string, returning an error if
/// any invalid digits are found during parsing. The parsing
/// is dictated by the options, which specifies special
/// float strings, required float components, digit separators,
/// exponent characters, and more. Returns a `Result` containing
/// either the parsed value, or an error containing any errors
/// that occurred during parsing.
///
/// * `FORMAT` - Flags and characters designating the number grammar.
/// * `bytes` - Slice containing a numeric string.
/// * `options` - Options to dictate number parsing.
///
/// The `FORMAT` packed struct is built using [`NumberFormatBuilder`].
/// Any invalid number format will prevent parsing, returning
/// the appropriate format error. If you are unsure which format
/// to use, use [`STANDARD`].
///
/// [`NumberFormatBuilder`]: lexical_util::format::NumberFormatBuilder
/// [`STANDARD`]: lexical_util::format::STANDARD
fn from_lexical_with_options<const FORMAT: u128>(
bytes: &[u8],
options: &Self::Options,
) -> lexical_util::result::Result<Self>;
/// Checked parser for a string-to-number conversion.
///
/// This method parses until an invalid digit is found (or the end
/// of the string), returning the number of processed digits
/// and the parsed value until that point. Returns a `Result`
/// containing either the parsed value and the number of
/// processed digits, or an error containing any errors that
/// occurred during parsing.
///
/// * `FORMAT` - Flags and characters designating the number grammar.
/// * `bytes` - Slice containing a numeric string.
/// * `options` - Options to dictate number parsing.
///
/// The `FORMAT` packed struct is built using [`NumberFormatBuilder`].
/// Any invalid number format will prevent parsing, returning
/// the appropriate format error. If you are unsure which format
/// to use, use [`STANDARD`].
///
/// [`NumberFormatBuilder`]: lexical_util::format::NumberFormatBuilder
/// [`STANDARD`]: lexical_util::format::STANDARD
fn from_lexical_partial_with_options<const FORMAT: u128>(
bytes: &[u8],
options: &Self::Options,
) -> lexical_util::result::Result<(Self, usize)>;
}
};
}
// TO LEXICAL
/// Define ToLexical trait.
#[macro_export]
#[cfg(feature = "write")]
macro_rules! to_lexical {
() => {
/// Trait for numerical types that can be serialized to bytes.
///
/// To determine the number of bytes required to serialize a value to
/// string, check the associated constants from a required trait:
/// - [`FORMATTED_SIZE`]
/// - [`FORMATTED_SIZE_DECIMAL`]
///
/// [`FORMATTED_SIZE`]: lexical_util::constants::FormattedSize::FORMATTED_SIZE
/// [`FORMATTED_SIZE_DECIMAL`]: lexical_util::constants::FormattedSize::FORMATTED_SIZE_DECIMAL
pub trait ToLexical:
lexical_util::constants::FormattedSize + lexical_util::num::Number
{
/// Serializer for a number-to-string conversion.
///
/// Returns a subslice of the input buffer containing the written bytes,
/// starting from the same address in memory as the input slice.
///
/// * `value` - Number to serialize.
/// * `bytes` - Buffer to write number to.
///
/// # Safety
///
/// Safe as long as the caller has provided a buffer of at least
/// [`FORMATTED_SIZE_DECIMAL`] elements. If a smaller buffer is
/// provided, a buffer overflow is very likely.
///
/// [`FORMATTED_SIZE_DECIMAL`]: lexical_util::constants::FormattedSize::FORMATTED_SIZE_DECIMAL
unsafe fn to_lexical_unchecked<'a>(self, bytes: &'a mut [u8]) -> &'a mut [u8];
/// Serializer for a number-to-string conversion.
///
/// Returns a subslice of the input buffer containing the written bytes,
/// starting from the same address in memory as the input slice.
///
/// * `value` - Number to serialize.
/// * `bytes` - Buffer to write number to.
///
/// # Panics
///
/// Panics if the buffer is not of sufficient size. The caller
/// must provide a slice of sufficient size. In order to ensure
/// the function will not panic, ensure the buffer has at least
/// [`FORMATTED_SIZE_DECIMAL`] elements.
///
/// [`FORMATTED_SIZE_DECIMAL`]: lexical_util::constants::FormattedSize::FORMATTED_SIZE_DECIMAL
fn to_lexical<'a>(self, bytes: &'a mut [u8]) -> &'a mut [u8];
}
};
}
/// Define ToLexicalWithOptions trait.
#[macro_export]
#[cfg(feature = "write")]
macro_rules! to_lexical_with_options {
() => {
/// Trait for numerical types that can be serialized to bytes with custom options.
///
/// To determine the number of bytes required to serialize a value to
/// string, check the associated constants from a required trait:
/// - [`FORMATTED_SIZE`]
/// - [`FORMATTED_SIZE_DECIMAL`]
///
/// The `Options` type specifies the configurable options to provide.
///
/// [`FORMATTED_SIZE`]: lexical_util::constants::FormattedSize::FORMATTED_SIZE
/// [`FORMATTED_SIZE_DECIMAL`]: lexical_util::constants::FormattedSize::FORMATTED_SIZE_DECIMAL
pub trait ToLexicalWithOptions:
lexical_util::constants::FormattedSize + lexical_util::num::Number
{
/// Custom formatting options for writing a number.
type Options: lexical_util::options::WriteOptions;
/// Serializer for a number-to-string conversion.
///
/// Returns a subslice of the input buffer containing the written bytes,
/// starting from the same address in memory as the input slice.
///
/// * `FORMAT` - Flags and characters designating the number grammar.
/// * `value` - Number to serialize.
/// * `bytes` - Buffer to write number to.
/// * `options` - Options for number formatting.
///
/// # Safety
///
/// Safe as long as the caller has provided a buffer of at least
/// [`FORMATTED_SIZE`] elements. If a smaller buffer is provided, a
/// buffer overflow is very likely. If you are changing the
/// number significant digits written, the exponent break points,
/// or disabling scientific notation, you will need a larger buffer
/// than the one provided. An upper limit on the buffer size can
/// then be determined using [`WriteOptions::buffer_size`]. If you
/// are not using `min_significant_digits`, 1200 bytes is always
/// enough to hold the the output for a custom radix, and `400`
/// is always enough for decimal strings.
///
/// # Panics
///
/// **Floats Only**
///
/// These panics are only when using uncommon features for float
/// writing, represent configuration errors, so runtime error
/// handling is not provided.
///
/// Panics if the provided number format is invalid, or if the
/// mantissa radix is not equal to the exponent base
/// and the mantissa radix/exponent base combinations are
/// not in the following list:
///
/// - `4, 2`
/// - `8, 2`
/// - `16, 2`
/// - `32, 2`
/// - `16, 4`
///
/// Panics as well if the NaN or Inf string provided to the writer
/// is disabled, but the value provided is NaN or Inf, respectively.
///
/// [`WriteOptions::buffer_size`]: lexical_util::options::WriteOptions::buffer_size
/// [`FORMATTED_SIZE`]: lexical_util::constants::FormattedSize::FORMATTED_SIZE
unsafe fn to_lexical_with_options_unchecked<'a, const FORMAT: u128>(
self,
bytes: &'a mut [u8],
options: &Self::Options,
) -> &'a mut [u8];
/// Serializer for a number-to-string conversion.
///
/// Returns a subslice of the input buffer containing the written bytes,
/// starting from the same address in memory as the input slice.
///
/// * `FORMAT` - Flags and characters designating the number grammar.
/// * `value` - Number to serialize.
/// * `bytes` - Buffer to write number to.
/// * `options` - Options for number formatting.
///
/// # Panics
///
/// Panics if the buffer is not of sufficient size. The caller
/// must provide a slice of sufficient size. In order to ensure
/// the function will not panic, ensure the buffer has at least
/// [`FORMATTED_SIZE`] elements. If you are changing the
/// number significant digits written, the exponent break points,
/// or disabling scientific notation, you will need a larger buffer
/// than the one provided. An upper limit on the buffer size can
/// then be determined using [`WriteOptions::buffer_size`]. If you
/// are not using `min_significant_digits`, 1200 bytes is always
/// enough to hold the the output for a custom radix, and `400`
/// is always enough for decimal strings.
///
/// **Floats Only**
///
/// These panics are only when using uncommon features for float
/// writing, represent configuration errors, so runtime error
/// handling is not provided.
///
/// Also panics if the provided number format is invalid, or
/// if the mantissa radix is not equal to the exponent base
/// and the mantissa radix/exponent base combinations are
/// not in the following list:
///
/// - `4, 2`
/// - `8, 2`
/// - `16, 2`
/// - `32, 2`
/// - `16, 4`
///
/// Panics as well if the NaN or Inf string provided to the writer
/// is disabled, but the value provided is NaN or Inf, respectively.
///
/// [`WriteOptions::buffer_size`]: lexical_util::options::WriteOptions::buffer_size
/// [`FORMATTED_SIZE`]: lexical_util::constants::FormattedSize::FORMATTED_SIZE
fn to_lexical_with_options<'a, const FORMAT: u128>(
self,
bytes: &'a mut [u8],
options: &Self::Options,
) -> &'a mut [u8];
}
};
}