wasm-reed-solomon-erasure
This is a WebAssembly compiled version of the reed-solomon-erasure
library made by Rust to use Reed-Solomon erasure coding at a minimum in TypeScript/JavaScript.
How To Install
npm i wasm-reed-solomon-erasure
Usage
Example of use. This code converts the string "Hello World" into several shards.
(By default, it splits the string into 8 data shards and 2 parity shards.)
We then verify that the two shards can be recovered even if they are destroyed.
import {encode, reconstruct} from 'wasm-reed-solomon-erasure';
export const bufferToShards = (buf: Buffer, shardsCount = 10, parityShards = 2): Uint8Array[] => {
const dataShards = shardsCount - parityShards;
const input = new Uint8Array(buf);
const shardSize = Math.ceil(input.length / dataShards);
const shardData = [];
for (let i = 0; i < dataShards; i++) {
const array = new Uint8Array(shardSize);
shardData.push(array);
}
for (let i = 0; i < input.length; i++) {
const j = Math.floor(i / shardSize);
const k = i % shardSize;
shardData[j][k] = input[i];
}
return encode(shardData, parityShards);
};
export const shardsToBuffer = (shards: Uint8Array[], parityShards: number, deadSharedIndexes: number[]): Buffer => {
const result = reconstruct(
shards,
parityShards,
new Uint32Array(deadSharedIndexes),
);
const flatten = [];
const dataShards = shards.length - parityShards;
for (let i = 0; i < dataShards; i++) {
for (const v of result[i]) flatten.push(v);
}
return Buffer.from(flatten);
};
and
import {bufferToShards, shardsToArrayBuffer} from './reedSolomon';
const buf = Buffer.from('Hello World', 'utf-8');
const shards = bufferToShards(buf);
const corrupted = [...shards];
// Shard Destruction
corrupted[1] = new Uint8Array();
corrupted[2] = new Uint8Array();
const restoredBuffer = shardsToArrayBuffer(corrupted, 2, [1, 2]);
const array = new Uint8Array(restoredBuffer);
const restored = Buffer.from(array).toString('utf-8', 0, 'Hello World'.length);
console.log(restored); // Hello World
Notice
I have not done any error handling at all and will implement it next time.
Developing
🛠️ Build with wasm-pack build
wasm-pack build --target nodejs
🔬 Test in Headless Browsers with wasm-pack test
wasm-pack test --headless --chrome
🎁 Publish to NPM with wasm-pack publish
wasm-pack publish
ref:
