Struct Decimal 

pub struct Decimal { /* private fields */ }

An exact base-10 number: unscaled / 10^scale.

Implementations

impl Decimal

pub fn from_parts(unscaled: i128, scale: u32) -> Option<Self>

Construct from raw parts. None if scale exceeds the maximum precision, which would make the value unrepresentable.

pub fn unscaled(&self) -> i128

The unscaled integer digits (value = unscaled × 10^-scale).

pub fn scale(&self) -> u32

Digits after the decimal point, as declared. Preserved exactly: 12.3400 reports 4, not 2.

pub fn precision(&self) -> u32

Total significant digits — the p of DECIMAL(p, s). Zero has precision 1.

pub fn is_zero(&self) -> bool

True when the value is zero at any scale.

pub fn parse(s: &str) -> Option<Self>

Parse a decimal literal: optional sign, digits, optional fraction, optional e±nn exponent. The exponent is folded into the scale, so 1.5e3 parses as 1500 and 15e-3 as 0.015 — both exact.

Returns None for anything that is not a decimal literal, or that needs more than 38 significant digits. NEVER falls back to float parsing: silently accepting a value we cannot represent exactly is the bug this type exists to prevent.

pub fn rescale(&self, target: u32) -> Option<Self>

Rescale to target digits after the point. None when that would drop non-zero digits (an inexact narrowing) or overflow.

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

Exact ordering, independent of scale: 1.50 equals 1.5 in value even though they are distinct column values.

Compares by aligning scales in i128; if alignment would overflow it falls back to comparing sign, integer-digit count, and then digits pairwise — which needs no arithmetic at all and so is exact at any magnitude.

Trait Implementations

impl Clone for Decimal

fn clone(&self) -> Decimal

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Decimal

impl Debug for Decimal

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Decimal

fn deserialize<D: Deserializer<'de>>(d: D) -> Result<Self, D::Error>

Deserialize this value from the given Serde deserializer.

impl Display for Decimal

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

The canonical literal, with exactly scale fractional digits — the round-trip form. Decimal::parse(&d.to_string()) == Some(d) for every representable value, trailing zeros included.

impl Eq for Decimal

impl Hash for Decimal

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Decimal

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for Decimal

Value ordering, NOT the derived field order — 1.50 and 1.5 are Ordering::Equal here while remaining distinct under Eq.

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 Serialize for Decimal

Serialized as its canonical STRING, never a JSON number: a JSON number goes through f64 in most parsers (including JavaScript), which is exactly the corruption this type exists to prevent.

fn serialize<S: Serializer>(&self, s: S) -> Result<S::Ok, S::Error>

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Decimal