otmb/README.md

## README.md

      
    Raw
  

              README.md
            
          
    Reference


EmscriptenでビルドしたZstandardをブラウザ環境で動かす

Make

emcc -o zstd.js -O0 \
-s WASM=1 \
-s "MODULARIZE=1" \
-s EXPORTED_FUNCTIONS="['_ZSTD_isError', '_ZSTD_getFrameContentSize', '_ZSTD_decompress']" \
-s EXTRA_EXPORTED_RUNTIME_METHODS="['cwrap','ccall']" \
-s 'EXPORT_NAME="ZstdLib"' \
lib/libzstd.bc


## index.html
<html>
<head>
    <title>Zstd wasm test</title>
    <script type='text/javascript' src="./zstd.js"></script>
    <script type="text/javascript" src="./run.js"></script>
</head>
<body>

<script type="text/javascript">

ZstdLib().then(function(Module) {
    var zstd = new ZstdCodec(Module);
// === test ===
//     fetch('test.txt.zst')
//     .then(function(response) {
//         return response.arrayBuffer();
//     })
//     .then(function(bytes) {
//         var res = zstd.decompress(new Uint8Array(bytes));
//     });
});
</script>
</body>
</html>

## run.js
"use strict";

class ZstdCodec {

    constructor(Module) {
        this.zstd = Module;
        this.ZSTD_isError = this.zstd.cwrap('ZSTD_isError', 'number', ['number']);
        this.ZSTD_getFrameContentSize = this.zstd.cwrap('ZSTD_getFrameContentSize', 'number', ['array', 'number']);
        this.ZSTD_decompress = this.zstd.cwrap('ZSTD_decompress', 'number', ['number', 'number', 'array', 'number']);
    }

    isError(zstd_rc) {
        return this.ZSTD_isError(zstd_rc);
    }

    getFrameContentSize(zstd_bytes) {
        const content_size = this.ZSTD_getFrameContentSize(zstd_bytes, zstd_bytes.length);
        const content_size_limit = 1 * 1024 * 1024;
        return content_size <= content_size_limit ? content_size : null;
    }

    decompress(zstd_bytes) {
        console.log(zstd_bytes);
        const content_size = this.getFrameContentSize(zstd_bytes);
        if (!content_size) return null;
        const heap = this.zstd._malloc(content_size);
        try {
            const decompress_rc = this.ZSTD_decompress(heap, content_size, zstd_bytes, zstd_bytes.length);
            if (this.isError(decompress_rc) || decompress_rc != content_size) return null;

            return new Uint8Array(this.zstd.HEAPU8.buffer, heap, content_size);
        } finally {
            this.zstd._free(heap);
        }
    }
}
	<html>
	<head>
	<title>Zstd wasm test</title>
	<script type='text/javascript' src="./zstd.js"></script>
	<script type="text/javascript" src="./run.js"></script>
	</head>
	<body>

	<script type="text/javascript">

	ZstdLib().then(function(Module) {
	var zstd = new ZstdCodec(Module);
	// === test ===
	// fetch('test.txt.zst')
	// .then(function(response) {
	// return response.arrayBuffer();
	// })
	// .then(function(bytes) {
	// var res = zstd.decompress(new Uint8Array(bytes));
	// });
	});
	</script>
	</body>
	</html>
	"use strict";

	class ZstdCodec {

	constructor(Module) {
	this.zstd = Module;
	this.ZSTD_isError = this.zstd.cwrap('ZSTD_isError', 'number', ['number']);
	this.ZSTD_getFrameContentSize = this.zstd.cwrap('ZSTD_getFrameContentSize', 'number', ['array', 'number']);
	this.ZSTD_decompress = this.zstd.cwrap('ZSTD_decompress', 'number', ['number', 'number', 'array', 'number']);
	}

	isError(zstd_rc) {
	return this.ZSTD_isError(zstd_rc);
	}

	getFrameContentSize(zstd_bytes) {
	const content_size = this.ZSTD_getFrameContentSize(zstd_bytes, zstd_bytes.length);
	const content_size_limit = 1 * 1024 * 1024;
	return content_size <= content_size_limit ? content_size : null;
	}

	decompress(zstd_bytes) {
	console.log(zstd_bytes);
	const content_size = this.getFrameContentSize(zstd_bytes);
	if (!content_size) return null;
	const heap = this.zstd._malloc(content_size);
	try {
	const decompress_rc = this.ZSTD_decompress(heap, content_size, zstd_bytes, zstd_bytes.length);
	if (this.isError(decompress_rc) \|\| decompress_rc != content_size) return null;

	return new Uint8Array(this.zstd.HEAPU8.buffer, heap, content_size);
	} finally {
	this.zstd._free(heap);
	}
	}
	}