refactor: improve FakeBuffer polyfill

Author: antongolub

src/main/ts/buffer.ts

@@ -0,0 +1,46 @@
+export interface BufferLike extends Omit<Uint8Array, 'slice'> {
+  readUInt16BE(offset?: number): number
+  slice(start?: number, end?: number): BufferLike
+  toString(encoding?: 'hex'): string
+}
+
+export const FakeBuffer = {
+  alloc: (size: number, fill: number = 0): BufferLike => {
+    if (size < 0)
+      throw new RangeError('The value of \"size\" is out of range.')
+
+    const arr = new Uint8Array(size)
+    if (fill !== 0)
+      arr.fill(fill)
+
+    const buf = arr as BufferLike
+
+    return Object.assign(buf, {
+      readUInt16BE(offset: number = 0): number {
+        if (offset < 0 || offset + 2 > (this as any).length)
+          throw new RangeError(`RangeError: The value of "offset" is out of range. It must be >= 0 and <= 2. Received ${offset}`)
+
+        return (this as any)[offset] << 8 | (this as any)[offset + 1]
+      },
+      slice(start?: number, end?: number): BufferLike {
+          const sliced = Uint8Array.prototype.slice.call(this, start, end)
+
+          return Object.assign(sliced, {
+            readUInt16BE: buf.readUInt16BE,
+            slice: buf.slice,
+            toString: buf.toString,
+          }) as BufferLike
+      },
+      toString(encoding?: 'hex'): string {
+        if (encoding !== 'hex')
+          throw new Error("Only 'hex' encoding is supported in this polyfill")
+
+        return Array.from(this as any)
+          .map((b) => (b as number).toString(16).padStart(2, '0'))
+          .join('')
+      },
+    })
+  }
+}
+
+export const Buffer = (global as any || globalThis).Buffer || FakeBuffer

src/main/ts/core.ts

@@ -1,3 +1,5 @@
+import { Buffer, type BufferLike } from './buffer.ts'
+
 export const IPV4 = 'IPv4'
 export const IPV6 = 'IPv6'
 
@@ -25,19 +27,6 @@ export const setMode = (mode: 'legacy' | 'strict'): void => {
   throw new Error('mode must be either "legacy" or "strict"')
 }
 
-export function readUInt16BE(buf: Buffer | Uint8Array | DataView, offset: number = 0): number {
-  if (typeof (buf as Buffer).readUInt16BE === 'function') {
-    // Node.js Buffer or feross/buffer polyfill
-    return (buf as Buffer).readUInt16BE(offset)
-  }
-
-  const view = buf instanceof DataView
-    ? buf
-    : new DataView(buf.buffer, buf.byteOffset, buf.byteLength)
-
-  return view.getUint16(offset, false)
-}
-
 // Corresponds Nodejs.NetworkInterfaceBase
 export type Family = typeof IPV4 | typeof IPV6
 export function normalizeFamily(family?: string | number): Family {
@@ -137,7 +126,7 @@ export const fromLong = (n: number): string => {
 export const toLong = (ip: string): number =>
   ip.split('.').reduce((acc, octet) => (acc << 8) + Number(octet), 0) >>> 0
 
-export const toString = (buff: Buffer, offset = 0, length?: number): string => {
+export const toString = (buff: BufferLike, offset = 0, length?: number): string => {
   const o = ~~offset
   const l = length || (buff.length - offset)
 
@@ -148,15 +137,15 @@ export const toString = (buff: Buffer, offset = 0, length?: number): string => {
   // IPv6
   if (l === 16)
     return Array
-      .from({ length: l / 2 }, (_, i) => readUInt16BE(buff, o + i * 2).toString(16))
+      .from({ length: l / 2 }, (_, i) => buff.readUInt16BE(o + i * 2).toString(16))
       .join(':')
       .replace(/(^|:)0(:0)*:0(:|$)/, '$1::$3')
       .replace(/:{3,4}/, '::')
 
   throw new Error('Invalid buffer length for IP address')
 }
 
-export const toBuffer = (ip: string, buff?: Buffer, offset = 0): Buffer => {
+export const toBuffer = (ip: string, buff?: BufferLike, offset = 0): BufferLike => {
   offset = ~~offset
 
   if (isV4Format(ip)) {
@@ -345,7 +334,7 @@ export const isEqual = (a: string, b: string): boolean => {
   for (let i = 0; i < 10; i++) if (bb[i] !== 0) return false
 
   // next 2 bytes must be either 0x0000 or 0xffff (::ffff:ipv4)
-  const prefix = readUInt16BE(bb, 10)
+  const prefix = bb.readUInt16BE(10)
   if (prefix !== 0 && prefix !== 0xffff) return false
 
   // last 4 bytes must match IPv4 buffer

src/test/js/export.test.js

@@ -20,6 +20,7 @@ describe('core', () => {
     assert.equal(typeof core.isLoopback, 'function', 'core.isLoopback')
     assert.equal(typeof core.isPrivate, 'function', 'core.isPrivate')
     assert.equal(typeof core.isPublic, 'function', 'core.isPublic')
+    assert.equal(typeof core.isSpecial, 'function', 'core.isSpecial')
     assert.equal(typeof core.isV4, 'function', 'core.isV4')
     assert.equal(typeof core.isV4Format, 'function', 'core.isV4Format')
     assert.equal(typeof core.isV6, 'function', 'core.isV6')
@@ -31,7 +32,6 @@ describe('core', () => {
     assert.equal(typeof core.normalizeToLong, 'function', 'core.normalizeToLong')
     assert.equal(typeof core.not, 'function', 'core.not')
     assert.equal(typeof core.or, 'function', 'core.or')
-    assert.equal(typeof core.readUInt16BE, 'function', 'core.readUInt16BE')
     assert.equal(typeof core.setMode, 'function', 'core.setMode')
     assert.equal(typeof core.subnet, 'function', 'core.subnet')
     assert.equal(typeof core.toBuffer, 'function', 'core.toBuffer')
@@ -70,6 +70,7 @@ describe('index', () => {
     assert.equal(typeof index.default.isLoopback, 'function', 'index.default.isLoopback')
     assert.equal(typeof index.default.isPrivate, 'function', 'index.default.isPrivate')
     assert.equal(typeof index.default.isPublic, 'function', 'index.default.isPublic')
+    assert.equal(typeof index.default.isSpecial, 'function', 'index.default.isSpecial')
     assert.equal(typeof index.default.isV4, 'function', 'index.default.isV4')
     assert.equal(typeof index.default.isV4Format, 'function', 'index.default.isV4Format')
     assert.equal(typeof index.default.isV6, 'function', 'index.default.isV6')
@@ -81,7 +82,6 @@ describe('index', () => {
     assert.equal(typeof index.default.normalizeToLong, 'function', 'index.default.normalizeToLong')
     assert.equal(typeof index.default.not, 'function', 'index.default.not')
     assert.equal(typeof index.default.or, 'function', 'index.default.or')
-    assert.equal(typeof index.default.readUInt16BE, 'function', 'index.default.readUInt16BE')
     assert.equal(typeof index.default.setMode, 'function', 'index.default.setMode')
     assert.equal(typeof index.default.subnet, 'function', 'index.default.subnet')
     assert.equal(typeof index.default.toBuffer, 'function', 'index.default.toBuffer')
@@ -106,6 +106,7 @@ describe('index', () => {
     assert.equal(typeof index.ip.isLoopback, 'function', 'index.ip.isLoopback')
     assert.equal(typeof index.ip.isPrivate, 'function', 'index.ip.isPrivate')
     assert.equal(typeof index.ip.isPublic, 'function', 'index.ip.isPublic')
+    assert.equal(typeof index.ip.isSpecial, 'function', 'index.ip.isSpecial')
     assert.equal(typeof index.ip.isV4, 'function', 'index.ip.isV4')
     assert.equal(typeof index.ip.isV4Format, 'function', 'index.ip.isV4Format')
     assert.equal(typeof index.ip.isV6, 'function', 'index.ip.isV6')
@@ -117,7 +118,6 @@ describe('index', () => {
     assert.equal(typeof index.ip.normalizeToLong, 'function', 'index.ip.normalizeToLong')
     assert.equal(typeof index.ip.not, 'function', 'index.ip.not')
     assert.equal(typeof index.ip.or, 'function', 'index.ip.or')
-    assert.equal(typeof index.ip.readUInt16BE, 'function', 'index.ip.readUInt16BE')
     assert.equal(typeof index.ip.setMode, 'function', 'index.ip.setMode')
     assert.equal(typeof index.ip.subnet, 'function', 'index.ip.subnet')
     assert.equal(typeof index.ip.toBuffer, 'function', 'index.ip.toBuffer')
@@ -127,6 +127,7 @@ describe('index', () => {
     assert.equal(typeof index.isLoopback, 'function', 'index.isLoopback')
     assert.equal(typeof index.isPrivate, 'function', 'index.isPrivate')
     assert.equal(typeof index.isPublic, 'function', 'index.isPublic')
+    assert.equal(typeof index.isSpecial, 'function', 'index.isSpecial')
     assert.equal(typeof index.isV4, 'function', 'index.isV4')
     assert.equal(typeof index.isV4Format, 'function', 'index.isV4Format')
     assert.equal(typeof index.isV6, 'function', 'index.isV6')
@@ -138,7 +139,6 @@ describe('index', () => {
     assert.equal(typeof index.normalizeToLong, 'function', 'index.normalizeToLong')
     assert.equal(typeof index.not, 'function', 'index.not')
     assert.equal(typeof index.or, 'function', 'index.or')
-    assert.equal(typeof index.readUInt16BE, 'function', 'index.readUInt16BE')
     assert.equal(typeof index.setMode, 'function', 'index.setMode')
     assert.equal(typeof index.subnet, 'function', 'index.subnet')
     assert.equal(typeof index.toBuffer, 'function', 'index.toBuffer')

src/test/ts/buffer.test.ts

@@ -0,0 +1,33 @@
+import assert from 'node:assert'
+import {test, describe} from 'vitest'
+
+import { FakeBuffer } from '../../main/ts/buffer.ts'
+
+describe('buffer', () => {
+
+  test('FakeBuffer mimics to Buffer', () => {
+    assert.throws(() => Buffer.alloc(-1), /The value of "size" is out of range/)
+    assert.throws(() => FakeBuffer.alloc(-1), /The value of "size" is out of range/)
+
+    const b1 = Buffer.alloc(4, 1)
+    assert.equal(b1.length, 4)
+    assert.equal(b1.toString('hex'), '01010101')
+    assert.equal(b1.readUInt16BE(), 257)
+    assert.throws(() => b1.readUInt16BE(3), /The value of "offset" is out of range/)
+
+    const b2 = b1.slice(2)
+    assert.equal(b2.length, 2)
+    assert.equal(b2.toString('hex'), '0101')
+
+    const b3 = FakeBuffer.alloc(4, 1)
+    assert.equal(b3.length, 4)
+    assert.equal(b3.toString('hex'), '01010101')
+    assert.equal(b3.readUInt16BE(), 257)
+    assert.throws(() => b3.readUInt16BE(3), /The value of "offset" is out of range/)
+    assert.throws(() => b3.toString('base64'), /Only 'hex' encoding is supported in this polyfill/)
+
+    const b4 = b3.slice(2)
+    assert.equal(b4.length, 2)
+    assert.equal(b4.toString('hex'), '0101')
+  })
+})

target/cjs/core.cjs

@@ -35,14 +35,48 @@ __export(core_exports, {
   normalizeToLong: () => normalizeToLong,
   not: () => not,
   or: () => or,
-  readUInt16BE: () => readUInt16BE,
   setMode: () => setMode,
   subnet: () => subnet,
   toBuffer: () => toBuffer,
   toLong: () => toLong,
   toString: () => toString
 });
 module.exports = __toCommonJS(core_exports);
+
+// src/main/ts/buffer.ts
+var FakeBuffer = {
+  alloc: (size, fill = 0) => {
+    if (size < 0)
+      throw new RangeError('The value of "size" is out of range.');
+    const arr = new Uint8Array(size);
+    if (fill !== 0)
+      arr.fill(fill);
+    const buf = arr;
+    return Object.assign(buf, {
+      readUInt16BE(offset = 0) {
+        if (offset < 0 || offset + 2 > this.length)
+          throw new RangeError(`RangeError: The value of "offset" is out of range. It must be >= 0 and <= 2. Received ${offset}`);
+        return this[offset] << 8 | this[offset + 1];
+      },
+      slice(start, end) {
+        const sliced = Uint8Array.prototype.slice.call(this, start, end);
+        return Object.assign(sliced, {
+          readUInt16BE: buf.readUInt16BE,
+          slice: buf.slice,
+          toString: buf.toString
+        });
+      },
+      toString(encoding) {
+        if (encoding !== "hex")
+          throw new Error("Only 'hex' encoding is supported in this polyfill");
+        return Array.from(this).map((b) => b.toString(16).padStart(2, "0")).join("");
+      }
+    });
+  }
+};
+var Buffer2 = (global || globalThis).Buffer || FakeBuffer;
+
+// src/main/ts/core.ts
 var IPV4 = "IPv4";
 var IPV6 = "IPv6";
 var V4_RE = /^(\d{1,3}(\.|$)){4}$/;
@@ -68,13 +102,6 @@ var setMode = (mode) => {
   }
   throw new Error('mode must be either "legacy" or "strict"');
 };
-function readUInt16BE(buf, offset = 0) {
-  if (typeof buf.readUInt16BE === "function") {
-    return buf.readUInt16BE(offset);
-  }
-  const view = buf instanceof DataView ? buf : new DataView(buf.buffer, buf.byteOffset, buf.byteLength);
-  return view.getUint16(offset, false);
-}
 function normalizeFamily(family) {
   const f = `${family}`.toLowerCase().trim();
   return f === "6" || f === IPV6.toLowerCase() ? IPV6 : IPV4;
@@ -146,13 +173,13 @@ var toString = (buff, offset = 0, length) => {
   if (l === 4)
     return [...buff.subarray(o, o + l)].join(".");
   if (l === 16)
-    return Array.from({ length: l / 2 }, (_, i) => readUInt16BE(buff, o + i * 2).toString(16)).join(":").replace(/(^|:)0(:0)*:0(:|$)/, "$1::$3").replace(/:{3,4}/, "::");
+    return Array.from({ length: l / 2 }, (_, i) => buff.readUInt16BE(o + i * 2).toString(16)).join(":").replace(/(^|:)0(:0)*:0(:|$)/, "$1::$3").replace(/:{3,4}/, "::");
   throw new Error("Invalid buffer length for IP address");
 };
 var toBuffer = (ip, buff, offset = 0) => {
   offset = ~~offset;
   if (isV4Format(ip)) {
-    const res = buff || Buffer.alloc(offset + 4);
+    const res = buff || Buffer2.alloc(offset + 4);
     for (const byte of ip.split("."))
       res[offset++] = +byte & 255;
     return res;
@@ -173,7 +200,7 @@ var toBuffer = (ip, buff, offset = 0) => {
     } else {
       while (sections.length < 8) sections.push("0");
     }
-    const res = buff || Buffer.alloc(offset + 16);
+    const res = buff || Buffer2.alloc(offset + 16);
     for (const sec of sections) {
       const word = parseInt(sec, 16) || 0;
       res[offset++] = word >> 8;
@@ -185,7 +212,7 @@ var toBuffer = (ip, buff, offset = 0) => {
 };
 var fromPrefixLen = (prefixlen, family) => {
   family = prefixlen > 32 ? IPV6 : normalizeFamily(family);
-  const buff = Buffer.alloc(family === IPV6 ? 16 : 4);
+  const buff = Buffer2.alloc(family === IPV6 ? 16 : 4);
   for (let i = 0; i < buff.length; i++) {
     const bits = Math.min(prefixlen, 8);
     prefixlen -= bits;
@@ -196,7 +223,7 @@ var fromPrefixLen = (prefixlen, family) => {
 var mask = (addr, maskStr) => {
   const a = toBuffer(addr);
   const m = toBuffer(maskStr);
-  const out = Buffer.alloc(Math.max(a.length, m.length));
+  const out = Buffer2.alloc(Math.max(a.length, m.length));
   if (a.length === m.length) {
     for (let i = 0; i < a.length; i++) out[i] = a[i] & m[i];
   } else if (m.length === 4) {
@@ -278,7 +305,7 @@ var isEqual = (a, b) => {
   }
   if (bb.length === 4) [ab, bb] = [bb, ab];
   for (let i = 0; i < 10; i++) if (bb[i] !== 0) return false;
-  const prefix = readUInt16BE(bb, 10);
+  const prefix = bb.readUInt16BE(10);
   if (prefix !== 0 && prefix !== 65535) return false;
   for (let i = 0; i < 4; i++) if (ab[i] !== bb[i + 12]) return false;
   return true;
@@ -362,7 +389,6 @@ var isSpecial = (addr) => {
   normalizeToLong,
   not,
   or,
-  readUInt16BE,
   setMode,
   subnet,
   toBuffer,

target/dts/buffer.d.ts

@@ -0,0 +1,9 @@
+export interface BufferLike extends Omit<Uint8Array, 'slice'> {
+    readUInt16BE(offset?: number): number;
+    slice(start?: number, end?: number): BufferLike;
+    toString(encoding?: 'hex'): string;
+}
+export declare const FakeBuffer: {
+    alloc: (size: number, fill?: number) => BufferLike;
+};
+export declare const Buffer: BufferConstructor;

target/dts/core.d.ts

@@ -1,3 +1,4 @@
+import { type BufferLike } from './buffer.ts';
 export declare const IPV4 = "IPv4";
 export declare const IPV6 = "IPv6";
 export declare const V4_RE: RegExp;
@@ -9,7 +10,6 @@ export declare const isV6Format: (ip: string) => boolean;
 export declare const isV4: (ip: string) => boolean;
 export declare const isV6: (ip: string) => boolean;
 export declare const setMode: (mode: "legacy" | "strict") => void;
-export declare function readUInt16BE(buf: Buffer | Uint8Array | DataView, offset?: number): number;
 export type Family = typeof IPV4 | typeof IPV6;
 export declare function normalizeFamily(family?: string | number): Family;
 export declare const normalizeAddress: (addr: string | number) => string;
@@ -20,8 +20,8 @@ export declare const isLoopback: (addr: string | number) => boolean;
 export declare const loopback: (family?: string | number) => typeof V4_LB | typeof V6_LB;
 export declare const fromLong: (n: number) => string;
 export declare const toLong: (ip: string) => number;
-export declare const toString: (buff: Buffer, offset?: number, length?: number) => string;
-export declare const toBuffer: (ip: string, buff?: Buffer, offset?: number) => Buffer;
+export declare const toString: (buff: BufferLike, offset?: number, length?: number) => string;
+export declare const toBuffer: (ip: string, buff?: BufferLike, offset?: number) => BufferLike;
 export declare const fromPrefixLen: (prefixlen: number, family?: string | number) => string;
 export declare const mask: (addr: string, maskStr: string) => string;
 type Subnet = {

target/dts/index.d.ts

@@ -2,7 +2,6 @@ import * as core from './core.ts';
 export * from './address.ts';
 export * from './core.ts';
 export declare const ip: {
-    readUInt16BE(buf: Buffer | Uint8Array | DataView, offset?: number): number;
     normalizeFamily(family?: string | number): core.Family;
     IPV4: "IPv4";
     IPV6: "IPv6";
@@ -21,8 +20,8 @@ export declare const ip: {
     loopback: (family?: string | number) => "127.0.0.1" | "fe80::1";
     fromLong: (n: number) => string;
     toLong: (ip: string) => number;
-    toString: (buff: Buffer, offset?: number, length?: number) => string;
-    toBuffer: (ip: string, buff?: Buffer, offset?: number) => Buffer;
+    toString: (buff: import("./buffer.ts").BufferLike, offset?: number, length?: number) => string;
+    toBuffer: (ip: string, buff?: import("./buffer.ts").BufferLike, offset?: number) => import("./buffer.ts").BufferLike;
     fromPrefixLen: (prefixlen: number, family?: string | number) => string;
     mask: (addr: string, maskStr: string) => string;
     subnet: (addr: string, smask: string) => {