Adding upstream version 1.55.0+dfsg.upstream/1.55.0+dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

6 files changed, 1440 insertions, 0 deletions

diff --git a/src/lib/lz4/README.md b/src/lib/lz4/README.md
new file mode 100644
index 0000000..6fcf4f8
--- /dev/null
+++ b/src/lib/lz4/README.md
@@ -0,0 +1,52 @@
+## Purpose
+
+The purpose of this library is to implement LZ4 compression/decompression,
+as documented at the official LZ4 repository:
+
+https://github.com/lz4/lz4/blob/dev/doc/lz4_Block_format.md
+
+The files in this directory are developed as a separate project at:
+
+https://github.com/gorhill/lz4-wasm
+
+## Files
+
+### `lz4-block-codec-any.js`
+
+The purpose is to instantiate a WebAssembly- or pure javascript-based
+LZ4 block codec.
+
+If the chosen implementation is not specified, there will be an attempt to
+create a WebAssembly-based instance. If for whatever reason this fails, a
+pure javascript-based instance will be created.
+
+The script for either instance are dynamically loaded and only when needed,
+such that no resources are wasted by keeping in memory code which won't be
+used.
+ 
+### `lz4-block-codec-wasm.js`
+
+This contains the code to instantiate WebAssembly-based LZ4 block codec. Note
+that the WebAssembly module is loaded using a `same-origin` fetch, hence
+ensuring that no code outside the package is loaded.
+
+### `lz4-block-codec-js.js`
+
+This contains the code to instantiate pure javascript-based LZ4 block codec.
+
+This is used as a fallback implementation should WebAssembly not be available
+for whatever reason.
+
+### `lz4-block-codec.wasm`
+
+This is the WebAssembly module, loaded by `lz4-block-codec-wasm.js` using a
+`same-origin` fetch.
+
+### `lz4-block-codec.wat`
+
+The WebAssembly source code used to generate the WebAssembly module `lz4-block-codec.wasm`.
+
+    wat2wasm ./lz4-block-codec.wat -o ./lz4-block-codec.wasm
+    wasm-opt ./lz4-block-codec.wasm -O4 -o ./lz4-block-codec.wasm
+
+You can get `wat2wasm` at <https://github.com/WebAssembly/wabt>, and `wasm-opt` at <https://github.com/WebAssembly/binaryen>.
diff --git a/src/lib/lz4/lz4-block-codec-any.js b/src/lib/lz4/lz4-block-codec-any.js
new file mode 100644
index 0000000..daf141b
--- /dev/null
+++ b/src/lib/lz4/lz4-block-codec-any.js
@@ -0,0 +1,151 @@
+/*******************************************************************************
+
+    lz4-block-codec-any.js
+        A wrapper to instantiate a wasm- and/or js-based LZ4 block
+        encoder/decoder.
+    Copyright (C) 2018 Raymond Hill
+
+    BSD-2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are
+    met:
+
+    1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above
+    copyright notice, this list of conditions and the following disclaimer
+    in the documentation and/or other materials provided with the
+    distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+    Home: https://github.com/gorhill/lz4-wasm
+
+    I used the same license as the one picked by creator of LZ4 out of respect
+    for his creation, see https://lz4.github.io/lz4/
+
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+(function(context) {                    // >>>> Start of private namespace
+
+/******************************************************************************/
+
+const wd = (function() {
+    let url = document.currentScript.src;
+    let match = /[^\/]+$/.exec(url);
+    return match !== null ?
+        url.slice(0, match.index) :
+        '';
+})();
+
+const removeScript = function(script) {
+    if ( !script ) { return; }
+    if ( script.parentNode === null ) { return; }
+    script.parentNode.removeChild(script);
+};
+
+const createInstanceWASM = function() {
+    if ( context.LZ4BlockWASM instanceof Function ) {
+        const instance = new context.LZ4BlockWASM();
+        return instance.init().then(ok => ok ? instance : null);
+    }
+    if ( context.LZ4BlockWASM === null ) {
+        return Promise.resolve(null);
+    }
+    return new Promise(resolve => {
+        const script = document.createElement('script');
+        script.src = wd + 'lz4-block-codec-wasm.js';
+        script.addEventListener('load', ( ) => {
+            if ( context.LZ4BlockWASM instanceof Function === false ) {
+                context.LZ4BlockWASM = null;
+                resolve(null);
+                return;
+            }
+            const instance = new context.LZ4BlockWASM();
+            instance.init().then(ok => { resolve(ok ? instance : null); });
+        });
+        script.addEventListener('error', ( ) => {
+            context.LZ4BlockWASM = null;
+            resolve(null);
+        });
+        document.head.appendChild(script);
+        removeScript(script);
+    });
+};
+
+const createInstanceJS = function() {
+    if ( context.LZ4BlockJS instanceof Function ) {
+        const instance = new context.LZ4BlockJS();
+        return instance.init().then(ok => ok ? instance : null);
+    }
+    if ( context.LZ4BlockJS === null ) {
+        return Promise.resolve(null);
+    }
+    return new Promise(resolve => {
+        const script = document.createElement('script');
+        script.src = wd + 'lz4-block-codec-js.js';
+        script.addEventListener('load', ( ) => {
+            if ( context.LZ4BlockJS instanceof Function === false ) {
+                context.LZ4BlockJS = null;
+                resolve(null);
+                return;
+            }
+            const instance = new context.LZ4BlockJS();
+            instance.init().then(ok => { resolve(ok ? instance : null); });
+        });
+        script.addEventListener('error', ( ) => {
+            context.LZ4BlockJS = null;
+            resolve(null);
+        });
+        document.head.appendChild(script);
+        removeScript(script);
+    });
+};
+
+/******************************************************************************/
+
+context.lz4BlockCodec = {
+    createInstance: function(flavor) {
+        let instantiator;
+        if ( flavor === 'wasm' ) {
+            instantiator = createInstanceWASM;
+        } else if ( flavor === 'js' ) {
+            instantiator = createInstanceJS;
+        } else {
+            instantiator = createInstanceWASM || createInstanceJS;
+        }
+        return (instantiator)().then(instance => {
+            if ( instance ) { return instance; }
+            if ( flavor === undefined ) {
+                return createInstanceJS();
+            }
+            return null;
+        });
+    },
+    reset: function() {
+        context.LZ4BlockWASM = undefined;
+        context.LZ4BlockJS = undefined;
+    }
+};
+
+/******************************************************************************/
+
+})(this || self);                       // <<<< End of private namespace
+
+/******************************************************************************/
diff --git a/src/lib/lz4/lz4-block-codec-js.js b/src/lib/lz4/lz4-block-codec-js.js
new file mode 100644
index 0000000..809da66
--- /dev/null
+++ b/src/lib/lz4/lz4-block-codec-js.js
@@ -0,0 +1,297 @@
+/*******************************************************************************
+
+    lz4-block-codec-js.js
+        A javascript wrapper around a pure javascript implementation of
+        LZ4 block format codec.
+    Copyright (C) 2018 Raymond Hill
+
+    BSD-2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are
+    met:
+
+    1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above
+    copyright notice, this list of conditions and the following disclaimer
+    in the documentation and/or other materials provided with the
+    distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+    Home: https://github.com/gorhill/lz4-wasm
+
+    I used the same license as the one picked by creator of LZ4 out of respect
+    for his creation, see https://lz4.github.io/lz4/
+
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+(function(context) {                    // >>>> Start of private namespace
+
+/******************************************************************************/
+
+const growOutputBuffer = function(instance, size) {
+    if (
+        instance.outputBuffer === undefined ||
+        instance.outputBuffer.byteLength < size
+    ) {
+        instance.outputBuffer = new ArrayBuffer(size + 0xFFFF & 0x7FFF0000);
+    }
+    return instance.outputBuffer;
+};
+
+const encodeBound = function(size) {
+    return size > 0x7E000000 ?
+        0 :
+        size + (size / 255 | 0) + 16;
+};
+
+const encodeBlock = function(instance, iBuf, oOffset) {
+    let iLen = iBuf.byteLength;
+    if ( iLen >= 0x7E000000 ) { throw new RangeError(); }
+
+    // "The last match must start at least 12 bytes before end of block"
+    let lastMatchPos = iLen - 12;
+
+    // "The last 5 bytes are always literals"
+    let lastLiteralPos = iLen - 5;
+
+    if ( instance.hashTable === undefined ) {
+        instance.hashTable = new Int32Array(65536);
+    }
+    instance.hashTable.fill(-65536);
+
+    if ( iBuf instanceof ArrayBuffer ) {
+        iBuf = new Uint8Array(iBuf);
+    }
+
+    let oLen = oOffset + encodeBound(iLen);
+    let oBuf = new Uint8Array(growOutputBuffer(instance, oLen), 0, oLen);
+    let iPos = 0;
+    let oPos = oOffset;
+    let anchorPos = 0;
+
+    // sequence-finding loop
+    for (;;) {
+        let refPos;
+        let mOffset;
+        let sequence = iBuf[iPos] << 8 | iBuf[iPos+1] << 16 | iBuf[iPos+2] << 24;
+
+        // match-finding loop
+        while ( iPos <= lastMatchPos ) {
+            sequence = sequence >>> 8 | iBuf[iPos+3] << 24;
+            let hash = (sequence * 0x9E37 & 0xFFFF) + (sequence * 0x79B1 >>> 16) & 0xFFFF;
+            refPos = instance.hashTable[hash];
+            instance.hashTable[hash] = iPos;
+            mOffset = iPos - refPos;
+            if (
+                mOffset < 65536 &&
+                iBuf[refPos+0] === ((sequence       ) & 0xFF) &&
+                iBuf[refPos+1] === ((sequence >>>  8) & 0xFF) &&
+                iBuf[refPos+2] === ((sequence >>> 16) & 0xFF) &&
+                iBuf[refPos+3] === ((sequence >>> 24) & 0xFF)
+            ) {
+                break;
+            }
+            iPos += 1;
+        }
+
+        // no match found
+        if ( iPos > lastMatchPos ) { break; }
+
+        // match found
+        let lLen = iPos - anchorPos;
+        let mLen = iPos;
+        iPos += 4; refPos += 4;
+        while ( iPos < lastLiteralPos && iBuf[iPos] === iBuf[refPos] ) {
+            iPos += 1; refPos += 1;
+        }
+        mLen = iPos - mLen;
+        let token = mLen < 19 ? mLen - 4 : 15;
+
+        // write token, length of literals if needed
+        if ( lLen >= 15 ) {
+            oBuf[oPos++] = 0xF0 | token;
+            let l = lLen - 15;
+            while ( l >= 255 ) {
+                oBuf[oPos++] = 255;
+                l -= 255;
+            }
+            oBuf[oPos++] = l;
+        } else {
+            oBuf[oPos++] = (lLen << 4) | token;
+        }
+
+        // write literals
+        while ( lLen-- ) {
+            oBuf[oPos++] = iBuf[anchorPos++];
+        }
+
+        if ( mLen === 0 ) { break; }
+
+        // write offset of match
+        oBuf[oPos+0] = mOffset;
+        oBuf[oPos+1] = mOffset >>> 8;
+        oPos += 2;
+
+        // write length of match if needed
+        if ( mLen >= 19 ) {
+            let l = mLen - 19;
+            while ( l >= 255 ) {
+                oBuf[oPos++] = 255;
+                l -= 255;
+            }
+            oBuf[oPos++] = l;
+        }
+
+        anchorPos = iPos;
+    }
+
+    // last sequence is literals only
+    let lLen = iLen - anchorPos;
+    if ( lLen >= 15 ) {
+        oBuf[oPos++] = 0xF0;
+        let l = lLen - 15;
+        while ( l >= 255 ) {
+            oBuf[oPos++] = 255;
+            l -= 255;
+        }
+        oBuf[oPos++] = l;
+    } else {
+        oBuf[oPos++] = lLen << 4;
+    }
+    while ( lLen-- ) {
+        oBuf[oPos++] = iBuf[anchorPos++];
+    }
+
+    return new Uint8Array(oBuf.buffer, 0, oPos);
+};
+
+const decodeBlock = function(instance, iBuf, iOffset, oLen) {
+    let iLen = iBuf.byteLength;
+    let oBuf = new Uint8Array(growOutputBuffer(instance, oLen), 0, oLen);
+    let iPos = iOffset, oPos = 0;
+
+    while ( iPos < iLen ) {
+        let token = iBuf[iPos++];
+
+        // literals
+        let clen = token >>> 4;
+
+        // length of literals
+        if ( clen !== 0 ) {
+            if ( clen === 15 ) {
+                let l;
+                for (;;) {
+                    l = iBuf[iPos++];
+                    if ( l !== 255 ) { break; }
+                    clen += 255;
+                }
+                clen += l;
+            }
+
+            // copy literals
+            let end = iPos + clen;
+            while ( iPos < end ) {
+                oBuf[oPos++] = iBuf[iPos++];
+            }
+            if ( iPos === iLen ) { break; }
+        }
+
+        // match
+        let mOffset = iBuf[iPos+0] | (iBuf[iPos+1] << 8);
+        if ( mOffset === 0 || mOffset > oPos ) { return; }
+        iPos += 2;
+
+        // length of match
+        clen = (token & 0x0F) + 4;
+        if ( clen === 19 ) {
+            let l;
+            for (;;) {
+                l = iBuf[iPos++];
+                if ( l !== 255 ) { break; }
+                clen += 255;
+            }
+            clen += l;
+        }
+
+        // copy match
+        let mPos = oPos - mOffset;
+        let end = oPos + clen;
+        while ( oPos < end ) {
+            oBuf[oPos++] = oBuf[mPos++];
+        }
+    }
+
+    return oBuf;
+};
+
+/******************************************************************************/
+
+context.LZ4BlockJS = function() {
+    this.hashTable = undefined;
+    this.outputBuffer = undefined;
+};
+
+context.LZ4BlockJS.prototype = {
+    flavor: 'js',
+    init: function() {
+        return Promise.resolve(true);
+    },
+
+    reset: function() {
+        this.hashTable = undefined;
+        this.outputBuffer = undefined;
+    },
+
+    bytesInUse: function() {
+        let bytesInUse = 0;
+        if ( this.hashTable !== undefined ) {
+            bytesInUse += this.hashTable.byteLength;
+        }
+        if ( this.outputBuffer !== undefined ) {
+            bytesInUse += this.outputBuffer.byteLength;
+        }
+        return bytesInUse;
+    },
+
+    encodeBlock: function(input, outputOffset) {
+        if ( input instanceof ArrayBuffer ) {
+            input = new Uint8Array(input);
+        } else if ( input instanceof Uint8Array === false ) {
+            throw new TypeError();
+        }
+        return encodeBlock(this, input, outputOffset);
+    },
+
+    decodeBlock: function(input, inputOffset, outputSize) {
+        if ( input instanceof ArrayBuffer ) {
+            input = new Uint8Array(input);
+        } else if ( input instanceof Uint8Array === false ) {
+            throw new TypeError();
+        }
+        return decodeBlock(this, input, inputOffset, outputSize);
+    }
+};
+
+/******************************************************************************/
+
+})(this || self);                       // <<<< End of private namespace
+
+/******************************************************************************/
diff --git a/src/lib/lz4/lz4-block-codec-wasm.js b/src/lib/lz4/lz4-block-codec-wasm.js
new file mode 100644
index 0000000..46a9a67
--- /dev/null
+++ b/src/lib/lz4/lz4-block-codec-wasm.js
@@ -0,0 +1,195 @@
+/*******************************************************************************
+
+    lz4-block-codec-wasm.js
+        A javascript wrapper around a WebAssembly implementation of
+        LZ4 block format codec.
+    Copyright (C) 2018 Raymond Hill
+
+    BSD-2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are
+    met:
+
+    1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above
+    copyright notice, this list of conditions and the following disclaimer
+    in the documentation and/or other materials provided with the
+    distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+    Home: https://github.com/gorhill/lz4-wasm
+
+    I used the same license as the one picked by creator of LZ4 out of respect
+    for his creation, see https://lz4.github.io/lz4/
+
+*/
+
+/* global WebAssembly */
+
+'use strict';
+
+/******************************************************************************/
+
+(function(context) {                    // >>>> Start of private namespace
+
+/******************************************************************************/
+
+const wd = (function() {
+    let url = document.currentScript.src;
+    let match = /[^\/]+$/.exec(url);
+    return match !== null ?
+        url.slice(0, match.index) :
+        '';
+})();
+
+const growMemoryTo = function(wasmInstance, byteLength) {
+    let lz4api = wasmInstance.exports;
+    let neededByteLength = lz4api.getLinearMemoryOffset() + byteLength;
+    let pageCountBefore = lz4api.memory.buffer.byteLength >>> 16;
+    let pageCountAfter = (neededByteLength + 65535) >>> 16;
+    if ( pageCountAfter > pageCountBefore ) {
+        lz4api.memory.grow(pageCountAfter - pageCountBefore);
+    }
+    return lz4api.memory.buffer;
+};
+
+const encodeBlock = function(wasmInstance, inputArray, outputOffset) {
+    let lz4api = wasmInstance.exports;
+    let mem0 = lz4api.getLinearMemoryOffset();
+    let hashTableSize = 65536 * 4;
+    let inputSize = inputArray.byteLength;
+    if ( inputSize >= 0x7E000000 ) { throw new RangeError(); }
+    let memSize =
+        hashTableSize +
+        inputSize +
+        outputOffset + lz4api.lz4BlockEncodeBound(inputSize);
+    let memBuffer = growMemoryTo(wasmInstance, memSize);
+    let hashTable = new Int32Array(memBuffer, mem0, 65536);
+    hashTable.fill(-65536, 0, 65536);
+    let inputMem = new Uint8Array(memBuffer, mem0 + hashTableSize, inputSize);
+    inputMem.set(inputArray);
+    let outputSize = lz4api.lz4BlockEncode(
+        mem0 + hashTableSize,
+        inputSize,
+        mem0 + hashTableSize + inputSize + outputOffset
+    );
+    if ( outputSize === 0 ) { return; }
+    let outputArray = new Uint8Array(
+        memBuffer,
+        mem0 + hashTableSize + inputSize,
+        outputOffset + outputSize
+    );
+    return outputArray;
+};
+
+const decodeBlock = function(wasmInstance, inputArray, inputOffset, outputSize) {
+    let inputSize = inputArray.byteLength;
+    let lz4api = wasmInstance.exports;
+    let mem0 = lz4api.getLinearMemoryOffset();
+    let memSize = inputSize + outputSize;
+    let memBuffer = growMemoryTo(wasmInstance, memSize);
+    let inputArea = new Uint8Array(memBuffer, mem0, inputSize);
+    inputArea.set(inputArray);
+    outputSize = lz4api.lz4BlockDecode(
+        mem0 + inputOffset,
+        inputSize - inputOffset,
+        mem0 + inputSize
+    );
+    if ( outputSize === 0 ) { return; }
+    return new Uint8Array(memBuffer, mem0 + inputSize, outputSize);
+};
+
+/******************************************************************************/
+
+context.LZ4BlockWASM = function() {
+    this.lz4wasmInstance = undefined;
+};
+
+context.LZ4BlockWASM.prototype = {
+    flavor: 'wasm',
+
+    init: function() {
+        if (
+            typeof WebAssembly !== 'object' ||
+            typeof WebAssembly.instantiateStreaming !== 'function'
+        ) {
+            this.lz4wasmInstance = null;
+        }
+        if ( this.lz4wasmInstance === null ) {
+            return Promise.resolve(false);
+        }
+        if ( this.lz4wasmInstance instanceof WebAssembly.Instance ) {
+            return Promise.resolve(true);
+        }
+        if ( this.lz4wasmInstance === undefined ) {
+            this.lz4wasmInstance = fetch(
+                wd + 'lz4-block-codec.wasm',
+                { mode: 'same-origin' }
+            ).then(
+                WebAssembly.instantiateStreaming
+            ).then(result => {
+                this.lz4wasmInstance = result && result.instance || null;
+            }).catch(reason => {
+                this.lz4wasmInstance = null;
+                console.info(reason);
+            }).then(( ) =>
+                this.lz4wasmInstance !== null
+            );
+        }
+        return this.lz4wasmInstance;
+    },
+
+    reset: function() {
+        this.lz4wasmInstance = undefined;
+    },
+
+    bytesInUse: function() {
+        return this.lz4wasmInstance instanceof WebAssembly.Instance ?
+            this.lz4wasmInstance.exports.memory.buffer.byteLength :
+            0;
+    },
+
+    encodeBlock: function(input, outputOffset) {
+        if ( this.lz4wasmInstance instanceof WebAssembly.Instance === false ) {
+            throw new Error('LZ4BlockWASM: not initialized');
+        }
+        if ( input instanceof ArrayBuffer ) {
+            input = new Uint8Array(input);
+        } else if ( input instanceof Uint8Array === false ) {
+            throw new TypeError();
+        }
+        return encodeBlock(this.lz4wasmInstance, input, outputOffset);
+    },
+
+    decodeBlock: function(input, inputOffset, outputSize) {
+        if ( this.lz4wasmInstance instanceof WebAssembly.Instance === false ) {
+            throw new Error('LZ4BlockWASM: not initialized');
+        }
+        if ( input instanceof ArrayBuffer ) {
+            input = new Uint8Array(input);
+        } else if ( input instanceof Uint8Array === false ) {
+            throw new TypeError();
+        }
+        return decodeBlock(this.lz4wasmInstance, input, inputOffset, outputSize);
+    }
+};
+
+/******************************************************************************/
+
+})(this || self);                       // <<<< End of private namespace
+
+/******************************************************************************/
diff --git a/src/lib/lz4/lz4-block-codec.wasm b/src/lib/lz4/lz4-block-codec.wasm
new file mode 100644
index 0000000..c57b079
--- /dev/null
+++ b/src/lib/lz4/lz4-block-codec.wasm
diff --git a/src/lib/lz4/lz4-block-codec.wat b/src/lib/lz4/lz4-block-codec.wat
new file mode 100644
index 0000000..4d9cf42
--- /dev/null
+++ b/src/lib/lz4/lz4-block-codec.wat
@@ -0,0 +1,745 @@
+;;
+;; lz4-block-codec.wat: a WebAssembly implementation of LZ4 block format codec
+;; Copyright (C) 2018 Raymond Hill
+;;
+;; BSD-2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+;;
+;; Redistribution and use in source and binary forms, with or without
+;; modification, are permitted provided that the following conditions are
+;; met:
+;; 
+;;   1. Redistributions of source code must retain the above copyright
+;; notice, this list of conditions and the following disclaimer.
+;; 
+;;   2. Redistributions in binary form must reproduce the above
+;; copyright notice, this list of conditions and the following disclaimer
+;; in the documentation and/or other materials provided with the
+;; distribution.
+;; 
+;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+;; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+;; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+;; OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+;; SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+;; LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+;; DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+;; THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+;; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+;; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+;;
+;; Home: https://github.com/gorhill/lz4-wasm
+;;
+;; I used the same license as the one picked by creator of LZ4 out of respect
+;; for his creation, see https://lz4.github.io/lz4/
+;;
+
+(module
+;;
+;; module start
+;;
+
+;; (func $log (import "imports" "log") (param i32 i32 i32))
+
+(memory (export "memory") 1)
+
+;;
+;; Public functions
+;;
+
+;;
+;; Return an offset to the first byte of usable linear memory.
+;; Might be useful in the future to reserve memory space for whatever purpose,
+;; like config variables, etc.
+;;
+(func $getLinearMemoryOffset (export "getLinearMemoryOffset") 
+    (result i32)
+    i32.const 0
+)
+
+;;
+;; unsigned int lz4BlockEncodeBound()
+;;
+;; Return the maximum size of the output buffer holding the compressed data.
+;;
+;; Reference implementation:
+;; https://github.com/lz4/lz4/blob/dev/lib/lz4.h#L156
+;;
+(func (export "lz4BlockEncodeBound")
+    (param $ilen i32)
+    (result i32)
+    local.get $ilen
+    i32.const 0x7E000000
+    i32.gt_u
+    if
+        i32.const 0
+        return
+    end
+    local.get $ilen
+    local.get $ilen
+    i32.const 255
+    i32.div_u
+    i32.add
+    i32.const 16
+    i32.add
+)
+
+;;
+;; unsigned int lz4BlockEncode(
+;;     unsigned int inPtr,
+;;     unsigned int ilen,
+;;     unsigned int outPtr
+;; )
+;;
+;; https://github.com/lz4/lz4/blob/dev/lib/lz4.c#L651
+;;
+;; The implementation below is modified from the reference one.
+;; 
+;; - There is no skip adjustment for repeated failure to find a match.
+;; 
+;; - All configurable values are hard-coded to match the generic version
+;;   of the compressor.
+;;
+;; Note the size of the input block is NOT encoded in the output buffer, it
+;; is for the caller to figure how they will save that information on
+;; their side. At this point it is probably a trivial amount of work to
+;; implement the LZ4 frame format, which encode the content size, but this
+;; is for another day.
+;;
+(func $lz4BlockEncode (export "lz4BlockEncode")
+    (param $inPtr i32)                  ;; pointer to start of input buffer
+    (param $ilen i32)                   ;; size of input buffer
+    (param $outPtr i32)                 ;; pointer to start of output buffer
+    (result i32)
+    (local $hashPtrBeg i32)             ;; start of hash buffer
+    (local $hashPtr i32)                ;; current hash entry
+    (local $anchorPtr i32)              ;; anchor position in input
+    (local $inPtrEnd1 i32)              ;; point in input at which match-finding must cease
+    (local $inPtrEnd2 i32)              ;; point in input at which match-length finding must cease
+    (local $inPtrEnd i32)               ;; point to end of input
+    (local $outPtrBeg i32)              ;; start of output buffer
+    (local $refPtr i32)                 ;; start of match in input
+    (local $seq32 i32)                  ;; 4-byte value from current input position
+    (local $llen i32)                   ;; length of found literals
+    (local $moffset i32)                ;; offset to found match from current input position
+    (local $mlen i32)                   ;; length of found match
+    local.get $ilen                     ;; empty input = empty output
+    i32.const 0x7E000000                ;; max input size: 0x7E000000
+    i32.gt_u
+    if
+        i32.const 0
+        return
+    end
+    local.get $ilen                     ;; "blocks < 13 bytes cannot be compressed"
+    i32.const 13
+    i32.lt_u
+    if
+        i32.const 0
+        return
+    end
+    call $getLinearMemoryOffset         ;; hash table is at start of usable memory
+    local.set $hashPtrBeg
+    local.get $inPtr
+    local.tee $anchorPtr
+    local.get $ilen
+    i32.add
+    local.tee $inPtrEnd
+    i32.const -5                        ;; "The last 5 bytes are always literals."
+    i32.add
+    local.tee $inPtrEnd2
+    i32.const -7                        ;; "The last match must start at least 12 bytes before end of block"
+    i32.add
+    local.set $inPtrEnd1
+    local.get $outPtr
+    local.set $outPtrBeg
+    ;;
+    ;; sequence processing loop
+    ;;
+    block $noMoreSequence loop $nextSequence
+        local.get $inPtr
+        local.get $inPtrEnd1
+        i32.ge_u                        ;; 5 or less bytes left?
+        br_if $noMoreSequence
+        local.get $inPtr                ;; first sequence of 3 bytes before match-finding loop
+        i32.load8_u
+        i32.const 8
+        i32.shl
+        local.get $inPtr
+        i32.load8_u offset=1
+        i32.const 16
+        i32.shl
+        i32.or
+        local.get $inPtr
+        i32.load8_u offset=2
+        i32.const 24
+        i32.shl
+        i32.or
+        local.set $seq32
+        ;;
+        ;; match-finding loop
+        ;;
+        loop $findMatch block $noMatchFound
+            local.get $inPtr
+            local.get $inPtrEnd2
+            i32.gt_u                    ;; less than 12 bytes left?
+            br_if $noMoreSequence
+            local.get $seq32            ;; update last byte of current sequence
+            i32.const 8
+            i32.shr_u
+            local.get $inPtr
+            i32.load8_u offset=3
+            i32.const 24
+            i32.shl
+            i32.or
+            local.tee $seq32
+            i32.const 0x9E3779B1        ;; compute 16-bit hash
+            i32.mul
+            i32.const 16
+            i32.shr_u                   ;; hash value is at top of stack
+            i32.const 2                 ;; lookup refPtr at hash entry
+            i32.shl
+            local.get $hashPtrBeg
+            i32.add
+            local.tee $hashPtr
+            i32.load
+            local.set $refPtr
+            local.get $hashPtr          ;; update hash entry with inPtr
+            local.get $inPtr
+            i32.store
+            local.get $inPtr
+            local.get $refPtr
+            i32.sub
+            local.tee $moffset          ;; remember match offset, we will need it in case of match
+            i32.const 0xFFFF
+            i32.gt_s                    ;; match offset > 65535 = unusable match
+            br_if $noMatchFound
+            ;;
+            ;; confirm match: different sequences can yield same hash
+            ;; compare-branch each byte to potentially save memory read ops
+            ;;
+            local.get $seq32            ;; byte 0
+            i32.const 0xFF
+            i32.and
+            local.get $refPtr
+            i32.load8_u
+            i32.ne                      ;; refPtr[0] !== inPtr[0]
+            br_if $noMatchFound
+            local.get $seq32            ;; byte 1
+            i32.const 8
+            i32.shr_u
+            i32.const 0xFF
+            i32.and
+            local.get $refPtr
+            i32.load8_u offset=1
+            i32.ne
+            br_if $noMatchFound         ;; refPtr[1] !== inPtr[1]
+            local.get $seq32            ;; byte 2
+            i32.const 16
+            i32.shr_u
+            i32.const 0xFF
+            i32.and
+            local.get $refPtr
+            i32.load8_u offset=2
+            i32.ne                      ;; refPtr[2] !== inPtr[2]
+            br_if $noMatchFound
+            local.get $seq32            ;; byte 3
+            i32.const 24
+            i32.shr_u
+            i32.const 0xFF
+            i32.and
+            local.get $refPtr
+            i32.load8_u offset=3
+            i32.ne                      ;; refPtr[3] !== inPtr[3]
+            br_if $noMatchFound
+            ;;
+            ;; a valid match has been found at this point
+            ;;
+            local.get $inPtr            ;; compute length of literals
+            local.get $anchorPtr
+            i32.sub
+            local.set $llen
+            local.get $inPtr            ;; find match length
+            i32.const 4                 ;; skip over confirmed 4-byte match
+            i32.add
+            local.set $inPtr
+            local.get $refPtr
+            i32.const 4
+            i32.add
+            local.tee $mlen             ;; remember refPtr to later compute match length
+            local.set $refPtr
+            block $endOfMatch loop      ;; scan input buffer until match ends
+                local.get $inPtr
+                local.get $inPtrEnd2
+                i32.ge_u
+                br_if $endOfMatch
+                local.get $inPtr
+                i32.load8_u
+                local.get $refPtr
+                i32.load8_u
+                i32.ne
+                br_if $endOfMatch
+                local.get $inPtr
+                i32.const 1
+                i32.add
+                local.set $inPtr
+                local.get $refPtr
+                i32.const 1
+                i32.add
+                local.set $refPtr
+                br 0
+            end end $endOfMatch
+            ;; encode token
+            local.get $outPtr           ;; output token
+            local.get $llen
+            local.get $refPtr
+            local.get $mlen
+            i32.sub
+            local.tee $mlen
+            call $writeToken
+            local.get $outPtr
+            i32.const 1
+            i32.add
+            local.set $outPtr
+            local.get $llen             ;; encode/write length of literals if needed
+            i32.const 15
+            i32.ge_s
+            if
+                local.get $outPtr
+                local.get $llen
+                call $writeLength
+                local.set $outPtr
+            end
+            ;; copy literals
+            local.get $outPtr
+            local.get $anchorPtr
+            local.get $llen
+            call $copy
+            local.get $outPtr
+            local.get $llen
+            i32.add
+            local.set $outPtr
+            ;; encode match offset
+            local.get $outPtr
+            local.get $moffset
+            i32.store8
+            local.get $outPtr
+            local.get $moffset
+            i32.const 8
+            i32.shr_u
+            i32.store8 offset=1
+            local.get $outPtr
+            i32.const 2
+            i32.add
+            local.set $outPtr
+            local.get $mlen             ;; encode/write length of match if needed
+            i32.const 15
+            i32.ge_s
+            if
+                local.get $outPtr
+                local.get $mlen
+                call $writeLength
+                local.set $outPtr
+            end
+            local.get $inPtr            ;; advance anchor to current position
+            local.set $anchorPtr
+            br $nextSequence
+        end $noMatchFound
+        local.get $inPtr                ;; no match found: advance to next byte
+        i32.const 1
+        i32.add
+        local.set $inPtr
+        br $findMatch end               ;; match offset > 65535 = unusable match
+    end end $noMoreSequence
+    ;;
+    ;; generate last (match-less) sequence if compression succeeded
+    ;;
+    local.get $outPtr
+    local.get $outPtrBeg
+    i32.eq
+    if
+        i32.const 0
+        return
+    end
+    local.get $outPtr
+    local.get $inPtrEnd
+    local.get $anchorPtr
+    i32.sub
+    local.tee $llen
+    i32.const 0
+    call $writeToken
+    local.get $outPtr
+    i32.const 1
+    i32.add
+    local.set $outPtr
+    local.get $llen
+    i32.const 15
+    i32.ge_u
+    if
+        local.get $outPtr
+        local.get $llen
+        call $writeLength
+        local.set $outPtr
+    end
+    local.get $outPtr
+    local.get $anchorPtr
+    local.get $llen
+    call $copy
+    local.get $outPtr                   ;; return number of written bytes
+    local.get $llen
+    i32.add
+    local.get $outPtrBeg
+    i32.sub
+)
+
+;;
+;; unsigned int lz4BlockDecode(
+;;     unsigned int inPtr,
+;;     unsigned int ilen
+;;     unsigned int outPtr
+;; )
+;;
+;; Reference:
+;; https://github.com/lz4/lz4/blob/dev/doc/lz4_Block_format.md
+;;
+(func (export "lz4BlockDecode")
+    (param $inPtr0 i32)                 ;; start of input buffer
+    (param $ilen i32)                   ;; length of input buffer
+    (param $outPtr0 i32)                ;; start of output buffer
+    (result i32)
+    (local $inPtr i32)                  ;; current position in input buffer
+    (local $inPtrEnd i32)               ;; end of input buffer
+    (local $outPtr i32)                 ;; current position in output buffer
+    (local $matchPtr i32)               ;; position of current match
+    (local $token i32)                  ;; sequence token
+    (local $clen i32)                   ;; number of bytes to copy 
+    (local $_ i32)                      ;; general purpose variable
+    local.get $ilen                     ;; if ( ilen == 0 ) { return 0; }
+    i32.eqz
+    if
+        i32.const 0
+        return
+    end
+    local.get $inPtr0
+    local.tee $inPtr                    ;; current position in input buffer
+    local.get $ilen
+    i32.add
+    local.set $inPtrEnd
+    local.get $outPtr0                  ;; start of output buffer
+    local.set $outPtr                   ;; current position in output buffer
+    block $noMoreSequence loop          ;; iterate through all sequences
+        local.get $inPtr
+        local.get $inPtrEnd
+        i32.ge_u
+        br_if $noMoreSequence           ;; break when nothing left to read in input buffer
+        local.get $inPtr                ;; read token -- consume one byte
+        i32.load8_u
+        local.get $inPtr
+        i32.const 1
+        i32.add
+        local.set $inPtr
+        local.tee $token                ;; extract length of literals from token
+        i32.const 4
+        i32.shr_u
+        local.tee $clen                 ;; consume extra length bytes if present
+        i32.eqz
+        if else
+            local.get $clen
+            i32.const 15
+            i32.eq
+            if loop
+                local.get $inPtr
+                i32.load8_u
+                local.get $inPtr
+                i32.const 1
+                i32.add
+                local.set $inPtr
+                local.tee $_
+                local.get $clen
+                i32.add
+                local.set $clen
+                local.get $_
+                i32.const 255
+                i32.eq
+                br_if 0
+            end end
+            local.get $outPtr           ;; copy literals to output buffer
+            local.get $inPtr
+            local.get $clen
+            call $copy
+            local.get $outPtr           ;; advance output buffer pointer past copy
+            local.get $clen
+            i32.add
+            local.set $outPtr
+            local.get $clen             ;; advance input buffer pointer past literals
+            local.get $inPtr
+            i32.add
+            local.tee $inPtr
+            local.get $inPtrEnd         ;; exit if this is the last sequence
+            i32.eq
+            br_if $noMoreSequence
+        end
+        local.get $outPtr               ;; read match offset
+        local.get $inPtr
+        i32.load8_u
+        local.get $inPtr
+        i32.load8_u offset=1
+        i32.const 8
+        i32.shl
+        i32.or
+        i32.sub
+        local.tee $matchPtr
+        local.get $outPtr               ;; match position can't be outside input buffer bounds
+        i32.eq
+        br_if $noMoreSequence
+        local.get $matchPtr
+        local.get $inPtrEnd
+        i32.lt_u
+        br_if $noMoreSequence
+        local.get $inPtr                ;; advance input pointer past match offset bytes
+        i32.const 2
+        i32.add
+        local.set $inPtr
+        local.get $token                ;; extract length of match from token
+        i32.const 15
+        i32.and
+        i32.const 4
+        i32.add
+        local.tee $clen
+        i32.const 19                    ;; consume extra length bytes if present
+        i32.eq
+        if loop
+            local.get $inPtr
+            i32.load8_u
+            local.get $inPtr
+            i32.const 1
+            i32.add
+            local.set $inPtr
+            local.tee $_
+            local.get $clen
+            i32.add
+            local.set $clen
+            local.get $_
+            i32.const 255
+            i32.eq
+            br_if 0
+        end end
+        local.get $outPtr               ;; copy match to output buffer
+        local.get $matchPtr
+        local.get $clen
+        call $copy
+        local.get $clen                 ;; advance output buffer pointer past copy
+        local.get $outPtr
+        i32.add
+        local.set $outPtr
+        br 0
+    end end $noMoreSequence
+    local.get $outPtr                   ;; return number of written bytes
+    local.get $outPtr0
+    i32.sub
+)
+
+;;
+;; Private functions
+;;
+
+;;
+;; Encode a sequence token
+;;
+;; Reference documentation:
+;; https://github.com/lz4/lz4/blob/dev/doc/lz4_Block_format.md
+;;
+(func $writeToken
+    (param $outPtr i32)
+    (param $llen i32)
+    (param $mlen i32)
+    local.get $outPtr
+    local.get $llen
+    i32.const 15
+    local.get $llen
+    i32.const 15
+    i32.lt_u
+    select
+    i32.const 4
+    i32.shl
+    local.get $mlen
+    i32.const 15
+    local.get $mlen
+    i32.const 15
+    i32.lt_u
+    select
+    i32.or
+    i32.store8
+)
+
+;;
+;; Encode and output length bytes. The return value is the pointer following
+;; the last byte written.
+;;
+;; Reference documentation:
+;; https://github.com/lz4/lz4/blob/dev/doc/lz4_Block_format.md
+;;
+(func $writeLength
+    (param $outPtr i32)
+    (param $len i32)
+    (result i32)
+    local.get $len
+    i32.const 15
+    i32.sub
+    local.set $len
+    loop
+        local.get $outPtr
+        local.get $len
+        i32.const 255
+        local.get $len
+        i32.const 255
+        i32.lt_u
+        select
+        i32.store8
+        local.get $outPtr
+        i32.const 1
+        i32.add
+        local.set $outPtr
+        local.get $len
+        i32.const 255
+        i32.sub
+        local.tee $len
+        i32.const 0
+        i32.ge_s
+        br_if 0
+    end
+    local.get $outPtr
+)
+
+;;
+;; Copy n bytes from source to destination.
+;;
+;; It is overlap-safe only from left-to-right -- which is only what is
+;; required in the current module.
+;;
+(func $copy
+    (param $dst i32)
+    (param $src i32)
+    (param $len i32)
+    block $lessThan8 loop
+        local.get $len
+        i32.const 8
+        i32.lt_u
+        br_if $lessThan8
+        local.get $dst
+        local.get $src
+        i32.load8_u
+        i32.store8
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=1
+        i32.store8 offset=1
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=2
+        i32.store8 offset=2
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=3
+        i32.store8 offset=3
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=4
+        i32.store8 offset=4
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=5
+        i32.store8 offset=5
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=6
+        i32.store8 offset=6
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=7
+        i32.store8 offset=7
+        local.get $dst
+        i32.const 8
+        i32.add
+        local.set $dst
+        local.get $src
+        i32.const 8
+        i32.add
+        local.set $src
+        local.get $len
+        i32.const -8
+        i32.add
+        local.set $len
+        br 0
+    end end $lessThan8
+    local.get $len
+    i32.const 4
+    i32.ge_u
+    if
+        local.get $dst
+        local.get $src
+        i32.load8_u
+        i32.store8
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=1
+        i32.store8 offset=1
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=2
+        i32.store8 offset=2
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=3
+        i32.store8 offset=3
+        local.get $dst
+        i32.const 4
+        i32.add
+        local.set $dst
+        local.get $src
+        i32.const 4
+        i32.add
+        local.set $src
+        local.get $len
+        i32.const -4
+        i32.add
+        local.set $len
+    end
+    local.get $len
+    i32.const 2
+    i32.ge_u
+    if
+        local.get $dst
+        local.get $src
+        i32.load8_u
+        i32.store8
+        local.get $dst
+        local.get $src
+        i32.load8_u offset=1
+        i32.store8 offset=1
+        local.get $dst
+        i32.const 2
+        i32.add
+        local.set $dst
+        local.get $src
+        i32.const 2
+        i32.add
+        local.set $src
+        local.get $len
+        i32.const -2
+        i32.add
+        local.set $len
+    end
+    local.get $len
+    i32.eqz
+    if else
+        local.get $dst
+        local.get $src
+        i32.load8_u
+        i32.store8
+    end
+)
+
+;;
+;; module end
+;;
+)