Krish/cpp algo by Animesh26526 · Pull Request #25 · kautilyadevaraj/SchedulingAlgorithmSimulator

Animesh26526 · 2026-03-23T19:33:13Z

Done Customizing the Web App as per our Needs

…e bug fixes

vercel · 2026-03-23T19:33:17Z

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Pull request overview

This PR refactors the scheduling simulator to support optional native C++ execution (via a Node.js addon) with a TypeScript fallback, adds priority-based algorithms plus context-switch overhead, and routes scheduling execution through a server-side API.

Changes:

Added a native-addon wrapper (lib/scheduling-native.ts) and C++ implementations/bindings for scheduling algorithms, with TS fallbacks.
Added Priority (preemptive/non-preemptive) algorithms and context switching time (rendered as CS blocks) and updated metrics calculations.
Updated UI/forms to include priority, moved scheduling execution to app/api/schedule, and refreshed docs/build scripts.

Reviewed changes

Copilot reviewed 29 out of 32 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
README.md	Updated feature list, run modes, and native build guidance.
package.json	Added node-gyp build/clean scripts and native dev/build modes.
lib/FirstComeFirstServe.ts	Re-export algorithm from native wrapper.
lib/RoundRobin.ts	Re-export algorithm from native wrapper.
lib/ShortestJobFirst.ts	Re-export algorithm from native wrapper.
lib/ShortestRemainingTimeFirst.ts	Re-export algorithm from native wrapper.
lib/PriorityNonPreemptive.ts	New re-export module for priority non-preemptive.
lib/PriorityPreemptive.ts	New re-export module for priority preemptive.
lib/scheduling-native.ts	Native addon loader + TS fallback implementations for all algorithms.
cpp/include/Process.h	Added C++ `Process` struct (includes `priority`).
cpp/include/Algorithms.h	Added C++ algorithm function declarations.
cpp/src/binding.cc	Added Node/V8 bindings and Process marshaling.
cpp/src/FirstComeFirstServe.cpp	Added C++ FCFS implementation.
cpp/src/RoundRobin.cpp	Added C++ RR implementation.
cpp/src/ShortestJobFirst.cpp	Added C++ SJF implementation.
cpp/src/ShortestRemainingTimeFirst.cpp	Added C++ SRTF implementation.
cpp/src/PriorityNonPreemptive.cpp	Added C++ priority non-preemptive implementation.
cpp/src/PriorityPreemptive.cpp	Added C++ priority preemptive implementation.
binding.gyp	Added native build configuration (C++20).
app/api/schedule/route.ts	New API route to run algorithms and apply context-switch blocks.
components/MainForm.tsx	Added priority/context-switch inputs, new algorithms, and server-side scheduling submission.
components/ProcessForm.tsx	Added `priority` field + validation and numeric inputs.
components/GanttChart.tsx	Added `CS` label support for context-switch blocks.
components/SummaryTable.tsx	Reworked CT/WT/TAT calculations using full timeline (idle + CS).
components/SummaryStatistics.tsx	Guarded throughput against divide-by-zero; Process type updated.
components/footer.tsx	Footer markup removed (now returns nothing).
BUILDING.md	Added native build documentation.
CPP_SETUP.md	Added VS Code/C++ setup guide.
CPP_INTEGRATION.md	Added integration write-up and usage notes.
.gitignore	Ignored node-gyp/native build artifacts and IDE files.

Comments suppressed due to low confidence (1)

components/SummaryTable.tsx:185

The totals row spans 4 columns, but the table has 6 columns (ID, AT, BT, CT, TAT, WT). As written, totalWaitingTime renders under the Turnaround column and totalTurnaroundTime under the Waiting column. Adjust the colSpan/cell order so totals align with their headers (or include both totals under the correct columns).

          <TableRow>
            <TableCell colSpan={4} className="pl-3 text-xs">
              Total
            </TableCell>
            <TableCell className="text-center">{totalWaitingTime}</TableCell>
            <TableCell className="text-center">{totalTurnaroundTime}</TableCell>
          </TableRow>

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Copilot · 2026-03-23T19:37:15Z

components/footer.tsx

-import Link from "next/link";
-import { GitHubLogoIcon } from "@radix-ui/react-icons";
-
 export default function Footer() {


Footer doesn’t return any JSX/null, so TypeScript will infer this component returns void and it cannot be used as a JSX component (it’s rendered in app/layout.tsx). Return a footer element again (or explicitly return null).

Suggested change

export default function Footer() {

export default function Footer() {

return null;

Copilot · 2026-03-23T19:37:16Z

lib/scheduling-native.ts

+  for (let i = 0; i < sortedProcesses.length; i++) {
+    let nextProcess = -1;
+    let highestPriority = Infinity;
+    let currentTime = 0;
+
+    // Calculate current time based on result
+    for (const proc of result) {
+      if (proc.process_id !== -1) {
+        currentTime += proc.burst_time;
+      }
+    }
+
+    // Find highest priority process that has arrived
+    for (let j = 0; j < sortedProcesses.length; j++) {
+      if (!completed[j] && sortedProcesses[j].arrival_time <= currentTime) {
+        if (sortedProcesses[j].priority < highestPriority) {
+          highestPriority = sortedProcesses[j].priority;
+          nextProcess = j;
+        }
+      }
+    }
+
+    // If no process available, find next arrival
+    if (nextProcess === -1) {
+      for (let j = 0; j < sortedProcesses.length; j++) {
+        if (!completed[j]) {
+          const gapDuration = sortedProcesses[j].arrival_time - currentTime;
+          if (gapDuration > 0) {
+            result.push({
+              process_id: -1,
+              arrival_time: -1,
+              burst_time: gapDuration,
+              priority: 0,
+              background: 'transparent',
+            });
+          }
+          break;
+        }
+      }
+      i = -1;
+      continue;
+    }
+
+    // Execute the selected process
+    const currentProcess = sortedProcesses[nextProcess];
+    result.push(currentProcess);
+    completed[nextProcess] = true;
+  }


The TypeScript fallback for Priority Non-Preemptive has a broken time-advance loop: currentTime is reset to 0 each iteration and recomputed ignoring idle blocks (process_id === -1). This can repeatedly add the same idle gap and restart (i = -1), potentially causing an infinite loop and incorrect schedules. Track currentTime as a single variable that advances by all blocks added to the timeline (including idle), and set each scheduled process slice’s start time consistently (as other algorithms do).

Copilot · 2026-03-23T19:37:16Z

package.json

+    "build-native": "node-gyp configure && node-gyp build",
+    "build-native-safe": "npm run build-native || true",
    "dev": "next dev",
    "build": "next build",
+    "dev:native": "npm run build-native-safe && next dev",
+    "build:native": "npm run build-native-safe && next build",


build-native-safe uses || true, which works in POSIX shells but fails on Windows because true isn’t a command in cmd.exe. Use a cross-platform no-op (e.g., || echo "Native build failed") or a small Node one-liner that exits 0 so dev:native/build:native work on Windows as documented.

Copilot · 2026-03-23T19:37:16Z

components/MainForm.tsx

+  const getInitialContextSwitch = () => {
+    const contextSwitch = searchParams?.get("contextSwitch");
+    if (contextSwitch) {
+      return parseInt(contextSwitch);


getInitialContextSwitch() returns parseInt(contextSwitch) without guarding NaN. If the query param is invalid, this can propagate NaN into the form and eventually into the schedule request (leading to burst_time: NaN context-switch blocks). Prefer const n = Number.parseInt(...); return Number.isNaN(n) ? 0 : n;.

Suggested change

return parseInt(contextSwitch);

const n = Number.parseInt(contextSwitch, 10);

return Number.isNaN(n) ? 0 : n;

Copilot · 2026-03-23T19:37:17Z

BUILDING.md

+- Node.js (v16 or higher)
+- Python 3.10 or higher (required for node-gyp)
+- For Windows: Visual Studio Build Tools with C++ support
+- For macOS: Xcode Command Line Tools
+- For Linux: Build tools (gcc, g++, make)


This doc says Node.js v16+ is supported, but the repo is on Next.js 14 (and @types/node 20), which requires a newer Node version. Please align this prerequisite with the actual minimum supported Node version (and keep it consistent with README.md).

Copilot · 2026-03-23T19:37:17Z

CPP_SETUP.md

+- Build the C++ addon automatically (via `postinstall`)
+


This guide claims npm install will "Build the C++ addon automatically (via postinstall)", but package.json doesn’t define a postinstall script in this PR. Either add the script or update the doc so setup instructions match the repository behavior.

Suggested change

- Build the C++ addon automatically (via `postinstall`)

It does not automatically build the C++ addon; to build it, run `npm run build-native` (see Step 4).

Copilot · 2026-03-23T19:37:17Z

CPP_INTEGRATION.md

+  "prebuild": "npm run build-native || true",
+  "dev": "npm run build-native && next dev",
+  "build": "npm run build-native && next build",


The package.json scripts shown here (e.g., prebuild, and dev/build always running build-native) don’t match the actual package.json in this PR (dev is plain next dev, and native build is behind dev:native/build:native). Please update this document to match the current scripts so contributors don’t follow incorrect commands.

Suggested change

"prebuild": "npm run build-native || true",

"dev": "npm run build-native && next dev",

"build": "npm run build-native && next build",

"dev": "next dev",

"dev:native": "npm run build-native && next dev",

"build": "next build",

"build:native": "npm run build-native && next build",

Copilot · 2026-03-23T19:37:18Z

lib/scheduling-native.ts

+if (typeof window === "undefined") {
+  try {
+    // eslint-disable-next-line @typescript-eslint/no-require-imports
+    const { createRequire } = require("module") as {
+      createRequire: (filename: string) => NodeRequire;
+    };
+    const nativeRequire = createRequire(__filename);
+    nativeAddon = nativeRequire("../build/Release/scheduling_algorithms") as NativeAddon;
+  } catch {
+    console.warn("Native C++ addon not found. Using TypeScript implementations.");
+  }


Native addon loading uses createRequire(__filename) and then requires ../build/Release/scheduling_algorithms relative to the compiled JS file location. In a Next.js production build, this module is typically bundled/emitted under .next/server/..., so that relative path often won’t point at the project-root build/Release output, causing the native path to never load in production. Consider resolving from process.cwd() (or another stable base) so the addon can be found reliably when it exists.

amiable-krish and others added 4 commits March 23, 2026 14:01

Algo to CPP

7163d58

Algo to CPP

202d159

Added Two More Scheduling Algorithms and Context Switch time with som…

a6b74ac

…e bug fixes

Added Native C++ build and Bug Fixes

4191f53

Copilot AI review requested due to automatic review settings March 23, 2026 19:33

Copilot started reviewing on behalf of Animesh26526 March 23, 2026 19:33 View session

Copilot AI reviewed Mar 23, 2026

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Krish/cpp algo#25

Krish/cpp algo#25
Animesh26526 wants to merge 5 commits intokautilyadevaraj:masterfrom
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	export default function Footer() {
	export default function Footer() {
	return null;

	return parseInt(contextSwitch);
	const n = Number.parseInt(contextSwitch, 10);
	return Number.isNaN(n) ? 0 : n;

	- Build the C++ addon automatically (via `postinstall`)

	It does not automatically build the C++ addon; to build it, run `npm run build-native` (see Step 4).

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