zstandard_web 1.3.20 
zstandard_web: ^1.3.20 copied to clipboard
landamessenger.comWeb platform implementation of zstandard
zstandard_web #
The web implementation of zstandard.
Installation #
Copy zstd.js and zstd.wasm on the web/ folder.
Include the library inside the <head>:
<!DOCTYPE html>
<html>
<head>
<script src="zstd.js"></script>
</head>
</html>
Usage #
void act() async {
final zstandard = ZstandardWeb();
Uint8List original = Uint8List.fromList([...]);
Uint8List? compressed = await zstandard.compress(original);
Uint8List? decompressed = await zstandard.decompress(compressed ?? Uint8List(0));
}
Generation #
zstd.js and zstd.wasm generation:
git clone https://github.com/emscripten-core/emsdk.git
git clone https://github.com/facebook/zstd.git
cd emsdk
./emsdk install latest
./emsdk activate latest
source "$HOME/Development/emsdk/emsdk_env.sh"
echo 'source "$HOME/Development/emsdk/emsdk_env.sh"' >> $HOME/.zprofile
cd zstd
emcc -O3 \
$(find lib/compress -name "*.c") \
$(find lib/decompress -name "*.c") \
$(find lib/common -name "*.c") \
-s WASM=1 \
-s EXPORT_NAME="zstdWasmModule" \
-s EXPORTED_FUNCTIONS="['_ZSTD_compress', '_ZSTD_decompress', '_malloc', '_free', '_ZSTD_getFrameContentSize', '_ZSTD_compressBound']" \
-o zstd.js
Include compressData and decompressData methods in zstd.js:
function compressData(inputData, compressionLevel) {
let inputPtr = Module._malloc(inputData.length);
Module.HEAPU8.set(inputData, inputPtr);
let outputBufferSize = Module._ZSTD_compressBound(inputData.length);
let outputPtr = Module._malloc(outputBufferSize);
let compressedSize = Module._ZSTD_compress(
outputPtr,
outputBufferSize,
inputPtr,
inputData.length,
compressionLevel
);
if (compressedSize < 0) {
console.error('Compression error, error code: ', compressedSize);
return null;
} else {
let compressedData = new Uint8Array(Module.HEAPU8.buffer, outputPtr, compressedSize);
Module._free(inputPtr);
Module._free(outputPtr);
return compressedData;
}
}
function decompressData(compressedData) {
let compressedPtr = Module._malloc(compressedData.length);
Module.HEAPU8.set(compressedData, compressedPtr);
let decompressedSize = Module._ZSTD_getFrameContentSize(compressedPtr, compressedData.length);
if (decompressedSize === -1 || decompressedSize === -2) {
console.error('Error in obtaining the original size of the data');
Module._free(compressedPtr);
return null;
}
let decompressedPtr = Module._malloc(decompressedSize);
let resultSize = Module._ZSTD_decompress(
decompressedPtr,
decompressedSize,
compressedPtr,
compressedData.length
);
if (resultSize < 0) {
console.error('Decompression error, error code: ', resultSize);
Module._free(compressedPtr);
Module._free(decompressedPtr);
return null;
} else {
let decompressedData = new Uint8Array(Module.HEAPU8.buffer, decompressedPtr, resultSize);
Module._free(compressedPtr);
Module._free(decompressedPtr);
return decompressedData;
}
}
Metadata
1
likes
0
points
84
downloads
Publisher
Weekly Downloads
Metadata
Web platform implementation of zstandard
Homepage
Repository (GitHub)
View/report issues
License
unknown (license)
Dependencies
flutter, flutter_web_plugins, web, zstandard_platform_interface
