Struct Number 

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

An opaque XRPL STNumber value: a decimal float represented as mantissa × 10^exponent.

The wire format is 12 bytes — an 8-byte big-endian i64 mantissa followed by a 4-byte big-endian i32 exponent. This is the representation every float_* host function consumes and produces, and it is distinct from the 8-byte IOUNumber value carried inside an IOU STAmount.

Important

This type is intentionally opaque: arithmetic and conversions MUST go through the host, which delegates to rippled’s Number class so results stay exactly consensus-compatible. The bytes are only ever produced by the host, so callers cannot construct an out-of-range value.

PartialEq/Eq compare the raw bytes. The host canonicalizes every value it emits, so bytewise equality matches semantic equality for host-produced values.

Implementations

impl Number

pub const ZERO: Number

The value 0.

pub const ONE: Number

The value 1 (mantissa = 1,000,000,000,000,000,000, exponent = -18).

pub const NEGATIVE_ONE: Number

The value -1 (mantissa = -1,000,000,000,000,000,000, exponent = -18).

pub fn from_int(value: i64) -> Result<Number>

Converts a signed integer to a Number.

pub fn from_uint(value: u64) -> Result<Number>

Converts an unsigned integer to a Number.

pub fn from_mant_exp(mantissa: i64, exponent: i32) -> Result<Number>

Constructs a Number from an explicit mantissa and exponent (mantissa × 10^exponent).

pub fn from_stamount(bytes: &[u8]) -> Result<Number>

Converts a serialized STAmount (e.g. from an amount field) to a Number.

pub fn from_stnumber(bytes: &[u8]) -> Result<Number>

Converts a serialized STNumber (12-byte) to a Number.

pub fn to_int(&self) -> Result<i64>

Converts this Number to a signed integer, rounding to nearest.

pub fn to_mant_exp(&self) -> Result<(i64, i32)>

Decomposes this Number into its (mantissa, exponent) components.

No rounding is applied — the value is already rounded/canonical.

pub fn add(&self, other: &Number, rounding: RoundingMode) -> Result<Number>

Returns self + other, rounding per rounding.

pub fn subtract(&self, other: &Number, rounding: RoundingMode) -> Result<Number>

Returns self - other, rounding per rounding.

pub fn multiply(&self, other: &Number, rounding: RoundingMode) -> Result<Number>

Returns self * other, rounding per rounding.

pub fn divide(&self, other: &Number, rounding: RoundingMode) -> Result<Number>

Returns self / other, rounding per rounding.

pub fn pow(&self, n: i32, rounding: RoundingMode) -> Result<Number>

Returns self raised to the integer power n, rounding per rounding.

Trait Implementations

impl Clone for Number

fn clone(&self) -> Number

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Number

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

Formats the value using the given formatter.

impl Eq for Number

impl FieldDecoder for Number

FieldDecoder for XRPL STNumber fields: decodes the 12-byte serialized value, failing if the host wrote a different number of bytes.

The bytes are taken as-is rather than routed back through float_from_stnumber: the host’s float representation is the STNumber serialization (rippled’s WASM host builds it with STNumber::add), so a value read off a transaction or ledger entry is already a canonical host-produced Number.

type Buffer = [u8; 12]

The buffer a get_field caller allocates before invoking the host function. Each type picks its own size (an associated type, not a const, so this stays on stable Rust).

fn empty_buffer() -> Self::Buffer

Returns a zero-initialized buffer of this type’s Buffer size.

fn decode(buf: Self::Buffer, bytes_written: usize) -> Result<Self, DecodeError>

Decodes Self from the full Buffer (as written by the host, then zero-padded to the buffer’s size), given bytes_written — the number of bytes the host actually wrote.

impl From<[u8; 12]> for Number

fn from(value: [u8; 12]) -> Self

Converts to this type from the input type.

impl FromCurrentTx for Number

impl FromLedger for Number

impl Ord for Number

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for Number

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for Number

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 StructuralPartialEq for Number