Decimal

Decimal is a fixed-point arithmetic wrapper designed for performance-critical environments such as HFT. It provides type-safe arithmetic on scaled integers with configurable tick precision and compile-time guarantees.

template <typename Tag, int Scale, int64_t TickSize = 1>
class Decimal {
  // ...
};

Purpose

• Avoid floating-point rounding errors by using integer math with fixed scaling.
• Provide clean, zero-cost abstractions for price/quantity units with compile-time type safety.

Parameters

Template Param	Description
Tag	Phantom type used to disambiguate unit domains (e.g. Price, Qty).
Scale	Number of sub-units per whole unit (e.g. 1000 = 3 decimal places).
TickSize	Granularity for tick-based rounding.

Key Features

Function	Description
fromDouble(double)	Converts a floating-point value to scaled integer with rounding.
toDouble()	Converts internal _raw value to double for logging/debugging.
raw()	Returns raw internal int64_t value.
roundToTick()	Rounds to the nearest multiple of TickSize.
isZero()	True if _raw == 0.
Arithmetic / Comparison Ops	Full suite of +, -, *, /, ==, <, <=, etc. on same-type values.

Notes

• Scale is enforced at compile time — Decimal<PriceTag, 1000> is a distinct type from Decimal<QuantityTag, 1000>.
• No virtual overhead, heap allocation, or runtime type checks.
• Supports tick-based alignment and arithmetic directly without conversions.
• Used throughout FLOX for price, quantity, and other numeric domains.