Q96.ts

src/Q96.ts

@@ -0,0 +1,27 @@
+// Q64.96 helpers (JavaScript)
+const Q96: bigint = 1n << 96n;
+
+function toQ96(x: string | number): bigint { // x: string | number -> bigint
+  // Use Decimal for precise parsing if needed
+  const [intPart, fracPart = ""] = String(x).split(".");
+  const frac: string = (fracPart + "0".repeat(30)).slice(0, 30); // up to 30 decimals
+  const scaled: bigint = BigInt(intPart) * 10n ** 30n + BigInt(frac);
+  return (scaled * Q96) / (10n ** 30n);
+}
+
+function fromQ96(q: bigint): string { // q: bigint -> string
+  const scaled: bigint = q * (10n ** 30n) / Q96;
+  const intPart = scaled / (10n ** 30n);
+  let frac = (scaled % (10n ** 30n)).toString().padStart(30, "0");
+  // trim trailing zeros
+  frac = frac.replace(/0+$/, "");
+  return frac.length ? `${intPart.toString()}.${frac}` : intPart.toString();
+}
+
+function mulQ96(a: bigint, b: bigint) { // (bigint, bigint) -> bigint in Q96
+  return (a * b) / Q96;
+}
+
+function divQ96(a: bigint, b: bigint) { // (bigint, bigint) -> bigint in Q96
+  return (a * Q96) / b;
+}