75 lines
2.6 KiB
Markdown
75 lines
2.6 KiB
Markdown
# zstddec
|
|
|
|
[](https://www.npmjs.com/package/zstddec)
|
|
[](https://bundlephobia.com/result?p=zstddec)
|
|
[](https://github.com/donmccurdy/zstddec/actions?query=workflow%3Abuild)
|
|
|
|
[ZSTD (Zstandard)](https://github.com/facebook/zstd) decoder for Web and Node.js, using WebAssembly.
|
|
|
|
## Installation
|
|
|
|
```shell
|
|
npm install --save zstddec
|
|
```
|
|
|
|
## API
|
|
|
|
```javascript
|
|
import { ZSTDDecoder } from 'zstddec';
|
|
|
|
const decoder = new ZSTDDecoder();
|
|
|
|
await decoder.init();
|
|
|
|
const decompressedArray = decoder.decode( compressedArray, uncompressedSize );
|
|
```
|
|
|
|
> **Limitations:** The decoder may fail with the error `wasm function signature contains illegal type` when the `uncompressedSize` is not known in advance and given to the `decode()` method. This is presumably a bug in the WASM bindings, which I am not yet sure how to fix.
|
|
|
|
## Contributing
|
|
|
|
To build the project locally, run:
|
|
|
|
```
|
|
yarn install
|
|
yarn build
|
|
```
|
|
|
|
To test changes:
|
|
|
|
```
|
|
yarn test
|
|
```
|
|
|
|
## Building from source
|
|
|
|
Compiled from https://github.com/facebook/zstd/tree/dev/build/single_file_libs, with the
|
|
following steps:
|
|
|
|
```shell
|
|
# build zstd
|
|
make
|
|
cd build/single_file_libs
|
|
./create_single_file_decoder.sh
|
|
|
|
# build wasm
|
|
emcc zstddeclib.c -s EXPORTED_FUNCTIONS="['_ZSTD_decompress', '_ZSTD_findDecompressedSize', '_ZSTD_isError', '_malloc', '_free']" -Wl,--no-entry -s WASM=1 -Oz -g0 -flto -s ALLOW_MEMORY_GROWTH=1 -s FILESYSTEM=0 -s STANDALONE_WASM=1 -DNDEBUG=1 -s PURE_WASI=0 -o zstddec.wasm
|
|
|
|
# build streaming wasm
|
|
emcc zstddeclib.c -s EXPORTED_FUNCTIONS="['_ZSTD_decompress', '_ZSTD_findDecompressedSize', '_ZSTD_createDCtx', '_ZSTD_decompressStream', '_ZSTD_freeDCtx', '_ZSTD_DStreamInSize', '_ZSTD_DStreamOutSize', '_malloc', '_free']" -Wl,--no-entry -s WASM=1 -Oz -g0 -flto -s ALLOW_MEMORY_GROWTH=1 -s FILESYSTEM=0 -s STANDALONE_WASM=1 -DNDEBUG=1 -s PURE_WASI=0 -o zstddec-stream.wasm
|
|
|
|
# encode WASM to base64
|
|
base64 -i zstddec.wasm > zstddec.txt
|
|
base64 -i zstddec-stream.wasm > zstddec-stream.txt
|
|
```
|
|
|
|
The base64 string written to `zstddec.txt` is embedded as the `wasm` variable at the bottom
|
|
of the source file. The rest of the file is written by hand, in order to avoid an additional JS
|
|
wrapper generated by Emscripten.
|
|
|
|
_Last built June 2025, zstd v1.5.7 (`f8745da6`), emscc v4.0.10_.
|
|
|
|
## License
|
|
|
|
JavaScript wrapper is provided under the MIT License, and the WASM ZSTD decoder is provided by Facebook under the BSD 3-Clause License.
|