Struct F32

pub struct F32(/* private fields */);

A 32-bit IBM floating point number.

This type supports the conversions:

• Transmuting to/from a u32 via from_bits(), to_bits()
• Transmuting to/from a big-endian [u8; 4] via from_be_bytes()/to_be_bytes()
• Lossily converting to an f32 via From/Into
• Losslessly converting to an f64 via From/Into

IBM F32 floats have slightly less precision than IEEE-754 f32 floats, but it covers a slightly larger domain. F32s of typical magnitude can be converted to f32 without rounding or other loss of precision. Converting F32s of large magnitude to f32 will cause rounding; F32s of extreme magnitude can also cause overflow and underflow to occur.

Every F32 can be precisely represented as an f64, without rounding, overflow, or underflow. Those seeking a lossless path to IEEE-754 should convert F32 to f64.

// Use the example -118.625:
//   https://en.wikipedia.org/wiki/IBM_hexadecimal_floating_point#Example
let foreign_float = ibmfloat::F32::from_bits(0b1_1000010_0111_0110_1010_0000_0000_0000);

let native_float = f32::from(foreign_float);
assert_eq!(native_float, -118.625f32);

let native_float: f32 = foreign_float.into();
assert_eq!(native_float, -118.625f32);

Implementations

impl F32

pub fn from_bits(value: u32) -> Self

Transmute a native-endian u64 into an F64.

let foreign_float = ibmfloat::F32::from_bits(0x46000001);

let native_float = f32::from(foreign_float); // potential loss of precision
assert_eq!(native_float, 1.0f32);

let native_float = f64::from(foreign_float); // always exact
assert_eq!(native_float, 1.0f64);

pub fn to_bits(self) -> u32

Transmute this F32 to a native-endian u32.

let foreign_float = ibmfloat::F32::from_bits(0x46000001);

assert_eq!(foreign_float.to_bits(), 0x46000001);

pub fn from_be_bytes(bytes: [u8; 4]) -> Self

Create a floating point value from its representation as a byte array in big endian.

let foreign_float = ibmfloat::F32::from_be_bytes([0x46, 0, 0, 1]);

assert_eq!(foreign_float.to_bits(), 0x46000001);

let native_float = f32::from(foreign_float);
assert_eq!(native_float, 1.0f32);

pub fn to_be_bytes(self) -> [u8; 4]

Return the memory representation of this floating point number as a byte array in big-endian (network) byte order.

let foreign_float = ibmfloat::F32::from_bits(0x46000001);

assert_eq!(foreign_float.to_be_bytes(), [0x46, 0, 0, 1]);

Trait Implementations

impl Clone for F32

fn clone(&self) -> F32

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for F32

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<F32> for f32

fn from(v: F32) -> Self

Converts to this type from the input type.

impl From<F32> for f64

fn from(v: F32) -> Self

Converts to this type from the input type.

impl PartialEq for F32

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for F32

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for F32