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function uncompress(source, uncompressedSize) {
/*
based off https://github.com/emscripten-core/emscripten/blob/main/third_party/mini-lz4.js
The license only applies to the body of this function (``uncompress``).
====
MiniLZ4: Minimal LZ4 block decoding and encoding.
based off of node-lz4, https://github.com/pierrec/node-lz4
====
Copyright (c) 2012 Pierre Curto
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
====
changes have the same license
*/
/**
* Decode a block. Assumptions: input contains all sequences of a
* chunk, output is large enough to receive the decoded data.
* If the output buffer is too small, an error will be thrown.
* If the returned value is negative, an error occurred at the returned offset.
*
* @param {ArrayBufferView} input input data
* @param {ArrayBufferView} output output data
* @param {number=} sIdx
* @param {number=} eIdx
* @return {number} number of decoded bytes
* @private
*/
function uncompressBlock (input, output, sIdx, eIdx) {
sIdx = sIdx || 0
eIdx = eIdx || (input.length - sIdx)
// Process each sequence in the incoming data
for (var i = sIdx, n = eIdx, j = 0; i < n;) {
var token = input[i++]
// Literals
var literals_length = (token >> 4)
if (literals_length > 0) {
// length of literals
var l = literals_length + 240
while (l === 255) {
l = input[i++]
literals_length += l
}
// Copy the literals
var end = i + literals_length
while (i < end) output[j++] = input[i++]
// End of buffer?
if (i === n) return j
}
// Match copy
// 2 bytes offset (little endian)
var offset = input[i++] | (input[i++] << 8)
// XXX 0 is an invalid offset value
if (offset === 0) return j
if (offset > j) return -(i-2)
// length of match copy
var match_length = (token & 0xf)
var l = match_length + 240
while (l === 255) {
l = input[i++]
match_length += l
}
// Copy the match
var pos = j - offset // position of the match copy in the current output
var end = j + match_length + 4 // minmatch = 4
while (j < end) output[j++] = output[pos++]
}
return j
}
var result = new ArrayBuffer(uncompressedSize);
var sourceIndex = 0;
var destIndex = 0;
var blockSize;
while((blockSize = (source[sourceIndex] | (source[sourceIndex + 1] << 8) | (source[sourceIndex + 2] << 16) | (source[sourceIndex + 3] << 24))) > 0)
{
sourceIndex += 4;
if (blockSize & 0x80000000)
{
blockSize &= 0x7FFFFFFFF;
for (var i = 0; i < blockSize; i++) {
result[destIndex++] = source[sourceIndex++];
}
}
else
{
destIndex += uncompressBlock(source, new Uint8Array(result, destIndex, uncompressedSize - destIndex), sourceIndex, sourceIndex + blockSize);
sourceIndex += blockSize;
}
}
return new Uint8Array(result, 0, uncompressedSize);
}