Struct Quantity 

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

A non-negative quantity backed by Decimal.

Example

use fin_primitives::types::Quantity;
use rust_decimal_macros::dec;
let q = Quantity::zero();
assert_eq!(q.value(), dec!(0));

Implementations

impl Quantity

pub fn new(d: Decimal) -> Result<Self, FinError>

Construct a validated Quantity.

Errors

Returns FinError::InvalidQuantity if d < 0.

pub fn zero() -> Self

Returns a zero quantity without allocation.

pub fn is_zero(&self) -> bool

Returns true if this quantity is zero.

pub fn value(&self) -> Decimal

Returns the inner Decimal value.

pub fn to_f64(&self) -> f64

Converts to f64 with possible precision loss.

pub fn from_f64(f: f64) -> Option<Self>

Constructs a Quantity from an f64. Returns None if f is not finite or < 0.

impl Quantity

pub fn checked_add(self, other: Quantity) -> Option<Quantity>

Adds other to this quantity, returning None if the result overflows.

pub fn checked_sub(self, other: Quantity) -> Option<Quantity>

Subtracts other from self, returning None if the result would be negative or overflow.

pub fn abs(self) -> Quantity

Returns the absolute value of this quantity’s underlying decimal.

Quantity values are normally non-negative, but this is useful when working with raw Decimal fields (e.g. from sub operations that yield negative Decimals wrapped in Quantity(d) via internal code paths).

pub fn split(self, n: usize) -> Vec<Quantity>

Splits this quantity into n equal parts, with the last absorbing any remainder.

Returns an empty vec if n is zero. Guarantees that sum(result) == self.value().

pub fn proportion_of(self, total: Quantity) -> Option<Decimal>

Returns self / total as a proportion, or None if total is zero.

Useful for computing position weight within a portfolio.

pub fn scale(self, factor: Decimal) -> Option<Quantity>

Multiplies this quantity by factor, returning None if the result is negative.

Useful for scaling position sizes by a fraction (e.g. 0.5 for half-position). Returns None if factor is negative (which would produce an invalid quantity).

Trait Implementations

impl Add for Quantity

Quantity + Quantity always yields a valid Quantity (sum of non-negatives is non-negative).

type Output = Quantity

The resulting type after applying the + operator.

fn add(self, rhs: Quantity) -> Quantity

Performs the + operation.

impl Clone for Quantity

fn clone(&self) -> Quantity

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Quantity

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Quantity

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for Quantity

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

Formats the value using the given formatter.

impl Mul<Decimal> for Quantity

Quantity * Decimal scales a quantity; yields raw Decimal.

type Output = Decimal

The resulting type after applying the * operator.

fn mul(self, rhs: Decimal) -> Decimal

Performs the * operation.

impl Mul<Quantity> for Price

Price * Quantity yields the notional value as Decimal.

type Output = Decimal

The resulting type after applying the * operator.

fn mul(self, rhs: Quantity) -> Decimal

Performs the * operation.

impl Ord for Quantity

fn cmp(&self, other: &Quantity) -> 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.

impl PartialEq for Quantity

fn eq(&self, other: &Quantity) -> 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 Quantity

fn partial_cmp(&self, other: &Quantity) -> 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 Quantity

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Sub for Quantity

Quantity - Quantity yields a raw Decimal (result may be negative).

type Output = Decimal

The resulting type after applying the - operator.

fn sub(self, rhs: Quantity) -> Decimal

Performs the - operation.

impl Copy for Quantity

impl Eq for Quantity

impl StructuralPartialEq for Quantity