Crate decimal_bytes 

decimal-bytes

Arbitrary precision decimals with lexicographically sortable byte encoding.

This crate provides a Decimal type that stores decimal numbers as bytes in a format that preserves numerical ordering when compared lexicographically. This makes it ideal for use in databases and search engines where efficient range queries on decimal values are needed.

Features

• Bytes-first storage: The primary representation is a compact byte array
• Lexicographic ordering: Byte comparison matches numerical comparison
• Arbitrary precision: Supports up to 131,072 digits before and 16,383 after decimal
• PostgreSQL NUMERIC compatibility: Full support for precision, scale, and special values
• Special values: Infinity, -Infinity, and NaN with correct PostgreSQL sort order

Example

use decimal_bytes::Decimal;
use std::str::FromStr;

// Create decimals
let a = Decimal::from_str("123.456").unwrap();
let b = Decimal::from_str("123.457").unwrap();

// Byte comparison matches numerical comparison
assert!(a.as_bytes() < b.as_bytes());
assert!(a < b);

// Display the value
assert_eq!(a.to_string(), "123.456");

// Special values (PostgreSQL compatible)
let inf = Decimal::infinity();
let nan = Decimal::nan();
assert!(a < inf);
assert!(inf < nan);

Sort Order

The lexicographic byte order matches PostgreSQL NUMERIC:

-Infinity < negative numbers < zero < positive numbers < +Infinity < NaN

Special Value Semantics (PostgreSQL vs IEEE 754)

This library follows PostgreSQL semantics for special values, which differ from IEEE 754 floating-point:

Behavior	PostgreSQL / decimal-bytes	IEEE 754 float
NaN == NaN	true	false
NaN ordering	Greatest value (> Infinity)	Unordered
Infinity == Infinity	true	true

use decimal_bytes::Decimal;

let nan1 = Decimal::nan();
let nan2 = Decimal::nan();
let inf = Decimal::infinity();

// NaN equals itself (PostgreSQL behavior, unlike IEEE 754)
assert_eq!(nan1, nan2);

// NaN is greater than everything, including Infinity
assert!(nan1 > inf);

This makes Decimal suitable for use in indexes, sorting, and deduplication where consistent ordering and equality semantics are required.

Structs

Decimal

An arbitrary precision decimal number stored as sortable bytes.

Enums

DecimalError

Errors that can occur during decimal encoding/decoding.

SpecialValue

Special decimal values (IEEE 754 / PostgreSQL compatible)