mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
117 lines
3.6 KiB
JavaScript
117 lines
3.6 KiB
JavaScript
function uncompress(source, uncompressedSize) {
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/*
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based off https://github.com/emscripten-core/emscripten/blob/main/third_party/mini-lz4.js
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The license only applies to the body of this function (``uncompress``).
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====
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MiniLZ4: Minimal LZ4 block decoding and encoding.
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based off of node-lz4, https://github.com/pierrec/node-lz4
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====
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Copyright (c) 2012 Pierre Curto
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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====
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changes have the same license
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*/
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/**
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* Decode a block. Assumptions: input contains all sequences of a
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* chunk, output is large enough to receive the decoded data.
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* If the output buffer is too small, an error will be thrown.
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* If the returned value is negative, an error occurred at the returned offset.
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*
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* @param {ArrayBufferView} input input data
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* @param {ArrayBufferView} output output data
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* @param {number=} sIdx
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* @param {number=} eIdx
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* @return {number} number of decoded bytes
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* @private
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*/
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function uncompressBlock (input, output, sIdx, eIdx) {
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sIdx = sIdx || 0
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eIdx = eIdx || (input.length - sIdx)
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// Process each sequence in the incoming data
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for (var i = sIdx, n = eIdx, j = 0; i < n;) {
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var token = input[i++]
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// Literals
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var literals_length = (token >> 4)
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if (literals_length > 0) {
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// length of literals
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var l = literals_length + 240
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while (l === 255) {
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l = input[i++]
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literals_length += l
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}
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// Copy the literals
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var end = i + literals_length
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while (i < end) output[j++] = input[i++]
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// End of buffer?
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if (i === n) return j
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}
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// Match copy
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// 2 bytes offset (little endian)
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var offset = input[i++] | (input[i++] << 8)
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// XXX 0 is an invalid offset value
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if (offset === 0) return j
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if (offset > j) return -(i-2)
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// length of match copy
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var match_length = (token & 0xf)
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var l = match_length + 240
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while (l === 255) {
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l = input[i++]
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match_length += l
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}
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// Copy the match
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var pos = j - offset // position of the match copy in the current output
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var end = j + match_length + 4 // minmatch = 4
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while (j < end) output[j++] = output[pos++]
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}
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return j
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}
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var result = new ArrayBuffer(uncompressedSize);
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var sourceIndex = 0;
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var destIndex = 0;
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var blockSize;
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while((blockSize = (source[sourceIndex] | (source[sourceIndex + 1] << 8) | (source[sourceIndex + 2] << 16) | (source[sourceIndex + 3] << 24))) > 0)
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{
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sourceIndex += 4;
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if (blockSize & 0x80000000)
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{
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blockSize &= 0x7FFFFFFFF;
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for (var i = 0; i < blockSize; i++) {
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result[destIndex++] = source[sourceIndex++];
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}
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}
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else
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{
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destIndex += uncompressBlock(source, new Uint8Array(result, destIndex, uncompressedSize - destIndex), sourceIndex, sourceIndex + blockSize);
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sourceIndex += blockSize;
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}
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}
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return new Uint8Array(result, 0, uncompressedSize);
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}
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