Decimal
A Decimal implementation written in pure Rust suitable for financial calculations that require significant integral and fractional digits with no round-off errors.
The binary representation consists of a 96 bit integer number, a scaling factor used to specify the decimal fraction and a 1 bit sign. Because of this representation, trailing zeros are preserved and may be exposed when in string form. These can be truncated using the normalize
or round_dp
functions.
Usage
Decimal numbers can be created in a few distinct ways. The easiest and most optimal method of creating a Decimal is to use the procedural macro within the rust_decimal_macros
crate:
// Procedural macros need importing directly
use *;
let number = dec!;
Alternatively you can also use one of the Decimal number convenience functions:
use Decimal;
// Using an integer followed by the decimal points
let scaled = new; // 2.02
// From a string representation
let from_string = from_str.unwrap; // 2.02
// Using the `Into` trait
let my_int : Decimal = 3i32.into;
// Using the raw decimal representation
// 3.1415926535897932384626433832
let pi = from_parts;
Features
postgres
This feature enables a PostgreSQL communication module. It allows for reading and writing the Decimal
type by transparently serializing/deserializing into the NUMERIC
data type within PostgreSQL.
const_fn
This feature leverages constant functions within Rust which enables some performance optimizations at compile time. This feature is expected to become a default in future versions.