bare-buffer 3.7.0: Buffer.prototype.writeInt32LE

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify Buffer.prototype.writeInt32LE in pkg:npm/bare-buffer@3.7.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/bare-buffer@3.7.0
Demonstrate these symbols/APIs:
  - Buffer.prototype.writeInt32LE

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:38461e917a14b49eabed125f26ab482d02d0c5bf5a2113bba404aeb3402da368","contract":["writeInt32LE writes positive 32-bit signed integers in little-endian order and returns the offset after write","writeInt32LE writes negative 32-bit signed integers using two's complement encoding in little-endian byte order","writeInt32LE defaults offset to zero when offset parameter is omitted","writeInt32LE serializes maximum and minimum 32-bit signed integer boundary values accurately","writeInt32LE allows sequential multi-value writes into a single buffer using returned offset positions","writeInt32LE throws RangeError when write offset exceeds buffer boundary"],"goal":"verify Buffer.prototype.writeInt32LE in pkg:npm/bare-buffer@3.7.0","kind":"HOW","packages":["pkg:npm/bare-buffer@3.7.0"],"schemaVersion":1,"symbols":["Buffer.prototype.writeInt32LE"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/bare-buffer@3.7.0"],"schemaVersion":1,"subject":"pkg:npm/bare-buffer@3.7.0","symbols":["Buffer.prototype.writeInt32LE"],"verifierAdapter":"node-typescript@1"}

import { createRequire } from 'node:module';
import path from 'node:path';

const require = createRequire(import.meta.url);

if (typeof Bare === 'undefined') {
  const nodeBuffer = globalThis.Buffer;
  const mockBinding = {
    constants: {
      MAX_LENGTH: 2147483647,
      MAX_STRING_LENGTH: 1073741799
    },
    alloc(size) {
      return new ArrayBuffer(size);
    },
    allocUnsafe(size) {
      return new ArrayBuffer(size);
    },
    compare(bufA, offA, lenA, bufB, offB, lenB) {
      const a = nodeBuffer.from(bufA, offA, lenA);
      const b = nodeBuffer.from(bufB, offB, lenB);
      return a.compare(b);
    },
    toStringHex(buf, offset, len) {
      return nodeBuffer.from(buf, offset, len).toString('hex');
    },
    writeHex(buf, offset, len, string) {
      return nodeBuffer.from(buf, offset, len).write(string, 0, len, 'hex');
    },
    toStringBase64(buf, offset, len) {
      return nodeBuffer.from(buf, offset, len).toString('base64');
    },
    writeBase64(buf, offset, len, string) {
      return nodeBuffer.from(buf, offset, len).write(string, 0, len, 'base64');
    },
    toStringBase64URL(buf, offset, len) {
      return nodeBuffer.from(buf, offset, len).toString('base64url');
    },
    writeBase64URL(buf, offset, len, string) {
      return nodeBuffer.from(buf, offset, len).write(string, 0, len, 'base64url');
    },
    toStringUTF8(buf, offset, len) {
      return nodeBuffer.from(buf, offset, len).toString('utf8');
    },
    writeUTF8(buf, offset, len, string) {
      return nodeBuffer.from(buf, offset, len).write(string, 0, len, 'utf8');
    },
    validateUTF8(buf, offset, len) {
      return nodeBuffer.isUtf8 ? nodeBuffer.isUtf8(nodeBuffer.from(buf, offset, len)) : true;
    },
    byteLengthUTF8(string) {
      return nodeBuffer.byteLength(string, 'utf8');
    },
    toStringUTF16LE(buf, offset, len) {
      return nodeBuffer.from(buf, offset, len).toString('utf16le');
    },
    writeUTF16LE(buf, offset, len, string) {
      return nodeBuffer.from(buf, offset, len).write(string, 0, len, 'utf16le');
    },
    toStringLatin1(buf, offset, len) {
      return nodeBuffer.from(buf, offset, len).toString('latin1');
    },
    writeLatin1(buf, offset, len, string) {
      return nodeBuffer.from(buf, offset, len).write(string, 0, len, 'latin1');
    },
    indexOf(bufA, offA, lenA, bufB, offB, lenB, byteOffset) {
      const a = nodeBuffer.from(bufA, offA, lenA);
      const b = nodeBuffer.from(bufB, offB, lenB);
      return a.indexOf(b, byteOffset);
    },
    lastIndexOf(bufA, offA, lenA, bufB, offB, lenB, byteOffset) {
      const a = nodeBuffer.from(bufA, offA, lenA);
      const b = nodeBuffer.from(bufB, offB, lenB);
      return a.lastIndexOf(b, byteOffset);
    },
    swap16(buf, offset, len) {
      nodeBuffer.from(buf, offset, len).swap16();
    },
    swap32(buf, offset, len) {
      nodeBuffer.from(buf, offset, len).swap32();
    },
    swap64(buf, offset, len) {
      nodeBuffer.from(buf, offset, len).swap64();
    }
  };

  const mainPath = require.resolve('bare-buffer');
  const bindingPath = path.join(path.dirname(mainPath), 'binding.js');
  require.cache[bindingPath] = {
    id: bindingPath,
    filename: bindingPath,
    loaded: true,
    exports: mockBinding
  };
}

const Buffer = require('bare-buffer');

export function writeInt32LE(buffer, value, offset = 0) {
  return buffer.writeInt32LE(value, offset);
}

export function readInt32LE(buffer, offset = 0) {
  return buffer.readInt32LE(offset);
}

export { Buffer };
export default Buffer;

{
  "name": "sample-bare-buffer-write-int32-le",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-bare-buffer-write-int32-le",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "bare-buffer": "3.7.0"
      }
    },
    "node_modules/bare-buffer": {
      "version": "3.7.0",
      "resolved": "https://registry.npmjs.org/bare-buffer/-/bare-buffer-3.7.0.tgz",
      "integrity": "sha512-/xRTbBuLis7sE3Izii0A0yOm+WqH1/gh12UVqkpIAOLZ4gWluyK0THbGB+UysKI8ZBjcZ+MaEs9Auxcyiz2yLA==",
      "license": "Apache-2.0",
      "engines": {
        "bare": ">=1.20.0"
      }
    }
  }
}

{
  "name": "sample-bare-buffer-write-int32-le",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "description": "Clean-room verification of Buffer.prototype.writeInt32LE in bare-buffer",
  "license": "MIT-0",
  "dependencies": {
    "bare-buffer": "3.7.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify Buffer.prototype.writeInt32LE in pkg:npm/bare-buffer@3.7.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/bare-buffer@3.7.0"
  ],
  "symbols": [
    "Buffer.prototype.writeInt32LE"
  ]
}

import assert from 'node:assert/strict';
import Buffer, { writeInt32LE, readInt32LE } from '../index.js';

// 1. writeInt32LE writes positive 32-bit signed integers in little-endian order and returns the offset after write
{
  const buf = Buffer.alloc(8, 0);
  const nextOffset = buf.writeInt32LE(0x12345678, 2);
  assert.strictEqual(nextOffset, 6, 'writeInt32LE should return the offset immediately following written bytes (2 + 4)');
  assert.strictEqual(buf[2], 0x78, 'Least significant byte at offset 2');
  assert.strictEqual(buf[3], 0x56, 'Byte at offset 3');
  assert.strictEqual(buf[4], 0x34, 'Byte at offset 4');
  assert.strictEqual(buf[5], 0x12, 'Most significant byte at offset 5');
  assert.strictEqual(buf.readInt32LE(2), 0x12345678, 'readInt32LE at offset 2 should recover written positive value');
  assert.strictEqual(buf[0], 0, 'Byte before write region must remain untouched');
  assert.strictEqual(buf[1], 0, 'Byte before write region must remain untouched');
  assert.strictEqual(buf[6], 0, 'Byte after write region must remain untouched');
  assert.strictEqual(buf[7], 0, 'Byte after write region must remain untouched');
}

// 2. writeInt32LE writes negative 32-bit signed integers using two's complement encoding in little-endian byte order
{
  const buf = Buffer.alloc(8, 0);
  const nextOffset = buf.writeInt32LE(-1, 0);
  assert.strictEqual(nextOffset, 4, 'Writing -1 at offset 0 should return next offset 4');
  assert.deepStrictEqual(Array.from(buf.subarray(0, 4)), [0xff, 0xff, 0xff, 0xff], '-1 is represented as all 0xFF bytes');
  assert.strictEqual(buf.readInt32LE(0), -1, 'readInt32LE should recover -1');

  buf.writeInt32LE(-123456, 4);
  assert.deepStrictEqual(Array.from(buf.subarray(4, 8)), [0xc0, 0x1d, 0xfe, 0xff], '-123456 correctly serialized in little-endian');
  assert.strictEqual(buf.readInt32LE(4), -123456, 'readInt32LE should recover -123456');
}

// 3. writeInt32LE defaults offset to zero when offset parameter is omitted
{
  const buf = Buffer.alloc(4, 0);
  const nextOffset = buf.writeInt32LE(42);
  assert.strictEqual(nextOffset, 4, 'Omitted offset should default to 0 and return 4');
  assert.strictEqual(buf.readInt32LE(0), 42, 'readInt32LE at offset 0 should recover written value');
  assert.strictEqual(buf[0], 42, 'First byte contains value 42');
  assert.strictEqual(buf[1], 0, 'Second byte is 0');
  assert.strictEqual(buf[2], 0, 'Third byte is 0');
  assert.strictEqual(buf[3], 0, 'Fourth byte is 0');
}

// 4. writeInt32LE serializes maximum and minimum 32-bit signed integer boundary values accurately
{
  const buf = Buffer.alloc(8, 0);
  // Max signed 32-bit int: 2147483647 (0x7FFFFFFF) -> LE: [0xFF, 0xFF, 0xFF, 0x7F]
  buf.writeInt32LE(2147483647, 0);
  assert.strictEqual(buf.readInt32LE(0), 2147483647, 'Max 32-bit signed integer recovered');
  assert.deepStrictEqual(Array.from(buf.subarray(0, 4)), [0xff, 0xff, 0xff, 0x7f], 'Max int32 byte layout in little-endian');

  // Min signed 32-bit int: -2147483648 (-0x80000000) -> LE: [0x00, 0x00, 0x00, 0x80]
  buf.writeInt32LE(-2147483648, 4);
  assert.strictEqual(buf.readInt32LE(4), -2147483648, 'Min 32-bit signed integer recovered');
  assert.deepStrictEqual(Array.from(buf.subarray(4, 8)), [0x00, 0x00, 0x00, 0x80], 'Min int32 byte layout in little-endian');
}

// 5. writeInt32LE allows sequential multi-value writes into a single buffer using returned offset positions
{
  const buf = Buffer.alloc(12, 0);
  let pos = 0;
  pos = writeInt32LE(buf, 1000, pos);
  assert.strictEqual(pos, 4, 'First write advances position to 4');
  pos = writeInt32LE(buf, -2000, pos);
  assert.strictEqual(pos, 8, 'Second write advances position to 8');
  pos = writeInt32LE(buf, 3000, pos);
  assert.strictEqual(pos, 12, 'Third write advances position to 12');

  assert.strictEqual(readInt32LE(buf, 0), 1000, 'First value matches');
  assert.strictEqual(readInt32LE(buf, 4), -2000, 'Second value matches');
  assert.strictEqual(readInt32LE(buf, 8), 3000, 'Third value matches');
}

// 6. writeInt32LE throws RangeError when write offset exceeds buffer boundary
{
  const buf = Buffer.alloc(4, 0);
  assert.throws(
    () => buf.writeInt32LE(1, 1),
    { name: 'RangeError' },
    'Writing 4 bytes at offset 1 in 4-byte buffer exceeds bound and must throw RangeError'
  );
  assert.throws(
    () => buf.writeInt32LE(1, 4),
    { name: 'RangeError' },
    'Writing at offset equal to length must throw RangeError'
  );
  assert.throws(
    () => buf.writeInt32LE(1, -1),
    { name: 'RangeError' },
    'Writing at negative offset must throw RangeError'
  );
  assert.throws(
    () => buf.writeInt32LE(1, 'invalid'),
    { name: 'TypeError' },
    'Non-number offset must throw TypeError'
  );
}

console.log('All contract assertions for Buffer.prototype.writeInt32LE passed successfully.');