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Encode Functions #343

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Encode Functions #343

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fe3a728
Encode Functions
oshaboy Dec 24, 2024
f622a43
Update float.rs
oshaboy Dec 24, 2024
72defac
Update float.rs
oshaboy Dec 24, 2024
2a8aef5
Update float.rs
oshaboy Dec 24, 2024
eb59c05
Update float.rs
oshaboy Dec 24, 2024
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56 changes: 56 additions & 0 deletions src/float.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -796,6 +796,8 @@ pub trait FloatCore: Num + NumCast + Neg<Output = Self> + PartialOrd + Copy {
/// check(f64::NEG_INFINITY, 1 << 52, 972, -1);
/// ```
fn integer_decode(self) -> (u64, i16, i8);
fn integer_encode(m: u64, e: i16, s: i8) -> Self;
fn nan_from_payload(p: u64) -> Self;
}

impl FloatCore for f32 {
Expand All @@ -815,6 +817,16 @@ impl FloatCore for f32 {
integer_decode_f32(self)
}

#[inline]
fn integer_encode(mantissa: u64, exp: i16, sign: i8) -> f32 {
integer_encode_f32(mantissa, exp, sign)
}

#[inline]
fn nan_from_payload(payload: u64) -> f32 {
nan_from_payload_f32(payload)
}

forward! {
Self::is_nan(self) -> bool;
Self::is_infinite(self) -> bool;
Expand Down Expand Up @@ -877,6 +889,16 @@ impl FloatCore for f64 {
integer_decode_f64(self)
}

#[inline]
fn integer_encode(mantissa: u64, exp: i16, sign: i8) -> f64 {
integer_encode_f64(mantissa, exp, sign)
}

#[inline]
fn nan_from_payload(payload: u64) -> f64 {
nan_from_payload_f64(payload)
}

forward! {
Self::is_nan(self) -> bool;
Self::is_infinite(self) -> bool;
Expand Down Expand Up @@ -2060,6 +2082,20 @@ fn integer_decode_f32(f: f32) -> (u64, i16, i8) {
(mantissa as u64, exponent, sign)
}

fn integer_encode_f32(mantissa: u64, exp: i16, sign: i8) -> f32 {
let sign_mask: u32 = if sign < 0 { 0x8000_0000 } else { 0 };
if exp <= (-127 + 23) {
let mantissa_mask: u32 = ((mantissa as u32) & 0x7fffff) >> 1;
// Exponent bias + mantissa shift
f32::from_bits(sign_mask|mantissa_mask)
} else {
let exp_ = exp.max(128+23);
let exponent_mask: u32 = ((exp_ + 127 - 23) as u32) << 23;
let mantissa_mask: u32 = (mantissa as u32) & 0x7fffff;
// Exponent bias + mantissa shift
f32::from_bits(sign_mask|exponent_mask|mantissa_mask)
}
}
fn integer_decode_f64(f: f64) -> (u64, i16, i8) {
let bits: u64 = f.to_bits();
let sign: i8 = if bits >> 63 == 0 { 1 } else { -1 };
Expand All @@ -2074,6 +2110,26 @@ fn integer_decode_f64(f: f64) -> (u64, i16, i8) {
(mantissa, exponent, sign)
}

fn integer_encode_f64(mantissa: u64, exp: i16, sign: i8) -> f64 {
let sign_mask: u64 = if sign < 0 { 0x8000_0000_0000_0000 } else { 0 };
if exp <= (-1023 + 52) {
let mantissa_mask: u64 = (mantissa & 0xfffffffffffff) >> 1;
// Exponent bias + mantissa shift
f64::from_bits(sign_mask|mantissa_mask)
} else {
let exp_ = exp.max(1024 + 52);
let exponent_mask: u64 = ((exp_ + 1023 - 52) as u64) << 52;
let mantissa_mask: u64 = mantissa & 0xfffffffffffff;
// Exponent bias + mantissa shift
f64::from_bits(sign_mask|exponent_mask|mantissa_mask)
}
}
fn nan_from_payload_f64(payload: u64) -> f64 {
integer_encode_f64(payload, 1024+52, 0)
}
fn nan_from_payload_f32(payload: u64) -> f32 {
integer_encode_f32(payload, 128+52, 0)
}
#[cfg(feature = "std")]
float_impl_std!(f32 integer_decode_f32);
#[cfg(feature = "std")]
Expand Down