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use crate::fmt::{Debug, Display, Formatter, LowerExp, Result, UpperExp};
use crate::mem::MaybeUninit;
use crate::num::flt2dec;
use crate::num::fmt as numfmt;
#[doc(hidden)]
trait GeneralFormat: PartialOrd {
fn already_rounded_value_should_use_exponential(&self) -> bool;
}
macro_rules! impl_general_format {
($($t:ident)*) => {
$(impl GeneralFormat for $t {
fn already_rounded_value_should_use_exponential(&self) -> bool {
let abs = $t::abs_private(*self);
(abs != 0.0 && abs < 1e-4) || abs >= 1e+16
}
})*
}
}
impl_general_format! { f32 f64 }
#[inline(never)]
fn float_to_decimal_common_exact<T>(
fmt: &mut Formatter<'_>,
num: &T,
sign: flt2dec::Sign,
precision: usize,
) -> Result
where
T: flt2dec::DecodableFloat,
{
let mut buf: [MaybeUninit<u8>; 1024] = MaybeUninit::uninit_array();
let mut parts: [MaybeUninit<numfmt::Part<'_>>; 4] = MaybeUninit::uninit_array();
let formatted = flt2dec::to_exact_fixed_str(
flt2dec::strategy::grisu::format_exact,
*num,
sign,
precision,
&mut buf,
&mut parts,
);
fmt.pad_formatted_parts(&formatted)
}
#[inline(never)]
fn float_to_decimal_common_shortest<T>(
fmt: &mut Formatter<'_>,
num: &T,
sign: flt2dec::Sign,
precision: usize,
) -> Result
where
T: flt2dec::DecodableFloat,
{
let mut buf: [MaybeUninit<u8>; flt2dec::MAX_SIG_DIGITS] = MaybeUninit::uninit_array();
let mut parts: [MaybeUninit<numfmt::Part<'_>>; 4] = MaybeUninit::uninit_array();
let formatted = flt2dec::to_shortest_str(
flt2dec::strategy::grisu::format_shortest,
*num,
sign,
precision,
&mut buf,
&mut parts,
);
fmt.pad_formatted_parts(&formatted)
}
fn float_to_decimal_display<T>(fmt: &mut Formatter<'_>, num: &T) -> Result
where
T: flt2dec::DecodableFloat,
{
let force_sign = fmt.sign_plus();
let sign = match force_sign {
false => flt2dec::Sign::Minus,
true => flt2dec::Sign::MinusPlus,
};
if let Some(precision) = fmt.precision {
float_to_decimal_common_exact(fmt, num, sign, precision)
} else {
let min_precision = 0;
float_to_decimal_common_shortest(fmt, num, sign, min_precision)
}
}
#[inline(never)]
fn float_to_exponential_common_exact<T>(
fmt: &mut Formatter<'_>,
num: &T,
sign: flt2dec::Sign,
precision: usize,
upper: bool,
) -> Result
where
T: flt2dec::DecodableFloat,
{
let mut buf: [MaybeUninit<u8>; 1024] = MaybeUninit::uninit_array();
let mut parts: [MaybeUninit<numfmt::Part<'_>>; 6] = MaybeUninit::uninit_array();
let formatted = flt2dec::to_exact_exp_str(
flt2dec::strategy::grisu::format_exact,
*num,
sign,
precision,
upper,
&mut buf,
&mut parts,
);
fmt.pad_formatted_parts(&formatted)
}
#[inline(never)]
fn float_to_exponential_common_shortest<T>(
fmt: &mut Formatter<'_>,
num: &T,
sign: flt2dec::Sign,
upper: bool,
) -> Result
where
T: flt2dec::DecodableFloat,
{
let mut buf: [MaybeUninit<u8>; flt2dec::MAX_SIG_DIGITS] = MaybeUninit::uninit_array();
let mut parts: [MaybeUninit<numfmt::Part<'_>>; 6] = MaybeUninit::uninit_array();
let formatted = flt2dec::to_shortest_exp_str(
flt2dec::strategy::grisu::format_shortest,
*num,
sign,
(0, 0),
upper,
&mut buf,
&mut parts,
);
fmt.pad_formatted_parts(&formatted)
}
fn float_to_exponential_common<T>(fmt: &mut Formatter<'_>, num: &T, upper: bool) -> Result
where
T: flt2dec::DecodableFloat,
{
let force_sign = fmt.sign_plus();
let sign = match force_sign {
false => flt2dec::Sign::Minus,
true => flt2dec::Sign::MinusPlus,
};
if let Some(precision) = fmt.precision {
float_to_exponential_common_exact(fmt, num, sign, precision + 1, upper)
} else {
float_to_exponential_common_shortest(fmt, num, sign, upper)
}
}
fn float_to_general_debug<T>(fmt: &mut Formatter<'_>, num: &T) -> Result
where
T: flt2dec::DecodableFloat + GeneralFormat,
{
let force_sign = fmt.sign_plus();
let sign = match force_sign {
false => flt2dec::Sign::Minus,
true => flt2dec::Sign::MinusPlus,
};
if let Some(precision) = fmt.precision {
float_to_decimal_common_exact(fmt, num, sign, precision)
} else {
if num.already_rounded_value_should_use_exponential() {
let upper = false;
float_to_exponential_common_shortest(fmt, num, sign, upper)
} else {
let min_precision = 1;
float_to_decimal_common_shortest(fmt, num, sign, min_precision)
}
}
}
macro_rules! floating {
($ty:ident) => {
#[stable(feature = "rust1", since = "1.0.0")]
impl Debug for $ty {
fn fmt(&self, fmt: &mut Formatter<'_>) -> Result {
float_to_general_debug(fmt, self)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Display for $ty {
fn fmt(&self, fmt: &mut Formatter<'_>) -> Result {
float_to_decimal_display(fmt, self)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl LowerExp for $ty {
fn fmt(&self, fmt: &mut Formatter<'_>) -> Result {
float_to_exponential_common(fmt, self, false)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl UpperExp for $ty {
fn fmt(&self, fmt: &mut Formatter<'_>) -> Result {
float_to_exponential_common(fmt, self, true)
}
}
};
}
floating! { f32 }
floating! { f64 }