From 7765476a26c8e5043a5f95eae2dc434db533284a Mon Sep 17 00:00:00 2001
From: Jaco <jacogr@gmail.com>
Date: Tue, 7 Jun 2022 07:58:11 +0200
Subject: [PATCH] Use bitwise not as Math.floor replacement (#1518)

* Use bitwise not as Math.floor replacement

* No objectSpread in extractTime

* Flatten extractTime calls
---
 packages/util/src/array/chunk.ts        |  6 +++
 packages/util/src/array/flatten.ts      |  5 ++
 packages/util/src/array/shuffle.spec.ts |  5 ++
 packages/util/src/array/shuffle.ts      |  4 +-
 packages/util/src/bi/sqrt.ts            |  3 +-
 packages/util/src/bn/sqrt.ts            |  3 +-
 packages/util/src/extractTime.ts        | 65 ++++++++++---------------
 7 files changed, 49 insertions(+), 42 deletions(-)

diff --git a/packages/util/src/array/chunk.ts b/packages/util/src/array/chunk.ts
index 246208321..df6600d65 100644
--- a/packages/util/src/array/chunk.ts
+++ b/packages/util/src/array/chunk.ts
@@ -17,6 +17,12 @@
  */
 export function arrayChunk <T> (array: T[], chunkSize: number): T[][] {
   const outputSize = Math.ceil(array.length / chunkSize);
+
+  // noop for the single-split case
+  if (outputSize === 1) {
+    return [array];
+  }
+
   const output = Array<T[]>(outputSize);
 
   for (let i = 0; i < outputSize; i++) {
diff --git a/packages/util/src/array/flatten.ts b/packages/util/src/array/flatten.ts
index 4abe55c99..3d6321b1b 100644
--- a/packages/util/src/array/flatten.ts
+++ b/packages/util/src/array/flatten.ts
@@ -19,6 +19,11 @@
  * ```
  */
 export function arrayFlatten <T> (arrays: T[][]): T[] {
+  // noop for the single-entry case
+  if (arrays.length === 1) {
+    return arrays[0];
+  }
+
   // pre-allocate based on the combined size
   let size = 0;
 
diff --git a/packages/util/src/array/shuffle.spec.ts b/packages/util/src/array/shuffle.spec.ts
index db63d61c9..d3c83c774 100644
--- a/packages/util/src/array/shuffle.spec.ts
+++ b/packages/util/src/array/shuffle.spec.ts
@@ -1,8 +1,11 @@
 // Copyright 2017-2022 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import { performance } from '../test/performance';
 import { arrayRange, arrayShuffle } from '.';
 
+const ptest = arrayRange(16284);
+
 describe('arrayShuffle', (): void => {
   it('returns an empty array as-is', (): void => {
     expect(
@@ -28,4 +31,6 @@ describe('arrayShuffle', (): void => {
       JSON.stringify(inp)
     ).not.toEqual(JSON.stringify(out));
   });
+
+  performance('arrayShuffle', 1000, [[ptest]], arrayShuffle);
 });
diff --git a/packages/util/src/array/shuffle.ts b/packages/util/src/array/shuffle.ts
index e45baa964..f6e2e5c44 100644
--- a/packages/util/src/array/shuffle.ts
+++ b/packages/util/src/array/shuffle.ts
@@ -5,12 +5,14 @@ export function arrayShuffle <T> (input: T[]): T[] {
   const result = input.slice();
   let curr = result.length;
 
+  // noop for the single entry
   if (curr === 1) {
     return result;
   }
 
   while (curr !== 0) {
-    const rand = Math.floor(Math.random() * curr);
+    // ~~ is more performant than Math.floor
+    const rand = ~~(Math.random() * curr);
 
     curr--;
 
diff --git a/packages/util/src/bi/sqrt.ts b/packages/util/src/bi/sqrt.ts
index 8252705fb..456739bd3 100644
--- a/packages/util/src/bi/sqrt.ts
+++ b/packages/util/src/bi/sqrt.ts
@@ -24,7 +24,8 @@ export function nSqrt <ExtToBn extends ToBn | ToBigInt> (value: ExtToBn | BN | b
   // https://stackoverflow.com/questions/53683995/javascript-big-integer-square-root/
   // shortcut <= 2^53 - 1 to use the JS utils
   if (n <= _2pow53n) {
-    return BigInt(Math.floor(Math.sqrt(Number(n))));
+    // ~~ is more performant that Math.floor
+    return BigInt(~~Math.sqrt(Number(n)));
   }
 
   // Use sqrt(MAX_SAFE_INTEGER) as starting point. since we already know the
diff --git a/packages/util/src/bn/sqrt.ts b/packages/util/src/bn/sqrt.ts
index 9aa299de6..b55080a81 100644
--- a/packages/util/src/bn/sqrt.ts
+++ b/packages/util/src/bn/sqrt.ts
@@ -31,7 +31,8 @@ export function bnSqrt <ExtToBn extends ToBn> (value: ExtToBn | BN | bigint | st
   // https://stackoverflow.com/questions/53683995/javascript-big-integer-square-root/
   // shortcut <= 2^53 - 1 to use the JS utils
   if (n.lte(BN_MAX_INTEGER)) {
-    return new BN(Math.floor(Math.sqrt(n.toNumber())));
+    // ~~ More performant version of Math.floor
+    return new BN(~~Math.sqrt(n.toNumber()));
   }
 
   // Use sqrt(MAX_SAFE_INTEGER) as starting point. since we already know the
diff --git a/packages/util/src/extractTime.ts b/packages/util/src/extractTime.ts
index 8c257645e..d488b01b1 100644
--- a/packages/util/src/extractTime.ts
+++ b/packages/util/src/extractTime.ts
@@ -3,10 +3,9 @@
 
 import type { Time } from './types';
 
-import { objectSpread } from './object/spread';
-
-const HRS = 60 * 60;
-const DAY = HRS * 24;
+const MIN_MS = 60 * 1000;
+const HR_MS = MIN_MS * 60;
+const DAY_MS = HR_MS * 24;
 const ZERO: Time = { days: 0, hours: 0, milliseconds: 0, minutes: 0, seconds: 0 };
 
 /**
@@ -14,56 +13,44 @@ const ZERO: Time = { days: 0, hours: 0, milliseconds: 0, minutes: 0, seconds: 0
  * @summary Add together two Time arrays
  */
 
-function addTime (a: Time, b: Time): Time {
+function add (a: Partial<Time>, b: Time): Time {
   return {
-    days: a.days + b.days,
-    hours: a.hours + b.hours,
-    milliseconds: a.milliseconds + b.milliseconds,
-    minutes: a.minutes + b.minutes,
-    seconds: a.seconds + b.seconds
+    days: (a.days || 0) + b.days,
+    hours: (a.hours || 0) + b.hours,
+    milliseconds: (a.milliseconds || 0) + b.milliseconds,
+    minutes: (a.minutes || 0) + b.minutes,
+    seconds: (a.seconds || 0) + b.seconds
   };
 }
 
-function extractDays (milliseconds: number, hrs: number): Time {
-  const days = Math.floor(hrs / 24);
+function extractSecs (ms: number): Time {
+  const s = ms / 1000;
 
-  return addTime(objectSpread({}, ZERO, { days }), extractTime(milliseconds - (days * DAY * 1000)));
-}
+  if (s < 60) {
+    const seconds = ~~s;
 
-function extractHrs (milliseconds: number, mins: number): Time {
-  const hrs = mins / 60;
-
-  if (hrs < 24) {
-    const hours = Math.floor(hrs);
-
-    return addTime(objectSpread({}, ZERO, { hours }), extractTime(milliseconds - (hours * HRS * 1000)));
+    return add({ seconds }, extractTime(ms - (seconds * 1000)));
   }
 
-  return extractDays(milliseconds, hrs);
-}
+  const m = s / 60;
 
-function extractMins (milliseconds: number, secs: number): Time {
-  const mins = secs / 60;
+  if (m < 60) {
+    const minutes = ~~m;
 
-  if (mins < 60) {
-    const minutes = Math.floor(mins);
-
-    return addTime(objectSpread({}, ZERO, { minutes }), extractTime(milliseconds - (minutes * 60 * 1000)));
+    return add({ minutes }, extractTime(ms - (minutes * MIN_MS)));
   }
 
-  return extractHrs(milliseconds, mins);
-}
+  const h = m / 60;
 
-function extractSecs (milliseconds: number): Time {
-  const secs = milliseconds / 1000;
+  if (h < 24) {
+    const hours = ~~h;
 
-  if (secs < 60) {
-    const seconds = Math.floor(secs);
-
-    return addTime(objectSpread({}, ZERO, { seconds }), extractTime(milliseconds - (seconds * 1000)));
+    return add({ hours }, extractTime(ms - (hours * HR_MS)));
   }
 
-  return extractMins(milliseconds, secs);
+  const days = ~~(h / 24);
+
+  return add({ days }, extractTime(ms - (days * DAY_MS)));
 }
 
 /**
@@ -82,6 +69,6 @@ export function extractTime (milliseconds?: number): Time {
   return !milliseconds
     ? ZERO
     : milliseconds < 1000
-      ? objectSpread({}, ZERO, { milliseconds })
+      ? add({ milliseconds }, ZERO)
       : extractSecs(milliseconds);
 }