wasm-zfp

ZFP decompression compiled to WebAssembly

Introduction

This package provides a WebAssembly build of https://computing.llnl.gov/projects/zfp, the official ZFP library. A high-level API is provided to compress and decompress ZFP data with a prefixed ZFP_HEADER_FULL header.

Usage

Create ZFP compressed data. An example is given in the test/ directory generated with the following command:

# Take the 2x3x4 array of float32s in uncompressed.raw and compress it to compressed.zfp with a header
zfp -i uncompressed.raw -h -f -3 2 3 4 -a 1 -z compressed.zfp

Create the same output using this library (node.js example, browsers are also supported):

import { readFileSync } from "fs";
import Zfp from "wasm-zfp";

const uncompressed = readFileSync("uncompressed.raw");

// Wait for the WebAssembly module to load
await Zfp.isLoaded;
// Create an internal allocation for compression. This can be reused for
// multiple compressions
const zfpBuffer = Zfp.createBuffer();

try {
  // Create a ZfpInput object describing the uncompressed data
  const input = {
    data: new Float32Array(uncompressed.buffer, uncompressed.byteOffset, uncompressed.byteLength / 4),
    shape: [2, 3, 4, 0],
    strides: [1, 2, 6, 0],
    dimensions: 3,
  };

  // Compress the data using `tolerance` mode with a value of 1 and return an
  // Uint8Array containing the compressed data. `rate` and `precision` modes are
  // also available, and lossless compression will be used if no mode is set
  const result = Zfp.compress(zfpBuffer, input, { tolerance: 1 });
  console.log(result);
} catch (error) {
  console.error(error);
}

// Free the internal allocation when it is no longer needed
Zfp.freeBuffer(zfpBuffer);

Decompress the data:

import { readFileSync } from "fs";
import Zfp from "wasm-zfp";

const compressed = readFileSync("compressed.zfp");

// Wait for the WebAssembly module to load
await Zfp.isLoaded;
// Create an internal allocation for decompression. This can be reused for
// multiple decompressions
const zfpBuffer = Zfp.createBuffer();

try {
  // Decompress the Uint8Array `compressed` and return an object containing
  // metadata about the type and shape of the array, as well as the decompressed
  // typed array
  const result = Zfp.decompress(zfpBuffer, compressed);
  console.log(result);
} catch (error) {
  console.error(error);
}

// Free the internal allocation when it is no longer needed
Zfp.freeBuffer(zfpBuffer);

For the test/compressed.zfp file in this repository, the output is:

{
  data: Float32Array(24) [
     0,  1,  2,  3,  4,  5,  6,  7,
     8,  9, 10, 11, 12, 13, 14, 15,
    16, 17, 18, 19, 20, 21, 22, 23
  ],
  dataPointer: 1052800,
  bufferSize: 96,
  size: 96,
  scalarSize: 4,
  shape: [ 2, 3, 4, 0 ],
  stride: [ 1, 2, 6, 0 ],
  dimensions: 3,
  type: 3
}

The dataPointer field is an opaque pointer. The remaining fields come from the ZFP header and decompressed data.

Development

Docker is required to build the WebAssembly module.

1. yarn install
2. yarn build
3. yarn test

License

wasm-zfp is licensed under MIT License.

Releasing

1. Run yarn version --[major|minor|patch] to bump version
2. Run git push && git push --tags to push new tag
3. GitHub Actions will take care of the rest

Stay in touch

Join our Slack channel to ask questions, share feedback, and stay up to date on what our team is working on.