121 lines
3.3 KiB
Haxe
121 lines
3.3 KiB
Haxe
/*
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* Copyright (C)2005-2019 Haxe Foundation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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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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*
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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
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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package haxe.zip;
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enum Huffman {
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Found(i:Int);
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NeedBit(left:Huffman, right:Huffman);
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NeedBits(n:Int, table:Array<Huffman>);
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}
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class HuffTools {
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public function new() {}
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function treeDepth(t) {
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return switch (t) {
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case Found(_): 0;
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case NeedBits(_, _): throw "assert";
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case NeedBit(a, b):
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var da = treeDepth(a);
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var db = treeDepth(b);
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1 + ((da < db) ? da : db);
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}
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}
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function treeCompress(t) {
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var d = treeDepth(t);
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if (d == 0)
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return t;
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if (d == 1)
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return switch (t) {
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case NeedBit(a, b): NeedBit(treeCompress(a), treeCompress(b));
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default: throw "assert";
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}
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var size = 1 << d;
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var table = new Array();
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for (i in 0...size)
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table.push(Found(-1));
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treeWalk(table, 0, 0, d, t);
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return NeedBits(d, table);
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}
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function treeWalk(table, p, cd, d, t) {
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switch (t) {
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case NeedBit(a, b):
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if (d > 0) {
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treeWalk(table, p, cd + 1, d - 1, a);
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treeWalk(table, p | (1 << cd), cd + 1, d - 1, b);
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} else
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table[p] = treeCompress(t);
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default:
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table[p] = treeCompress(t);
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}
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}
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function treeMake(bits:haxe.ds.IntMap<Int>, maxbits:Int, v:Int, len:Int) {
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if (len > maxbits)
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throw "Invalid huffman";
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var idx = (v << 5) | len;
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if (bits.exists(idx))
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return Found(bits.get(idx));
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v <<= 1;
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len += 1;
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return NeedBit(treeMake(bits, maxbits, v, len), treeMake(bits, maxbits, v | 1, len));
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}
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public function make(lengths, pos, nlengths, maxbits) {
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if (nlengths == 1) {
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return NeedBit(Found(0), Found(0));
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}
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var counts = new Array();
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var tmp = new Array();
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if (maxbits > 32)
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throw "Invalid huffman";
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for (i in 0...maxbits) {
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counts.push(0);
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tmp.push(0);
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}
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for (i in 0...nlengths) {
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var p = lengths[i + pos];
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if (p >= maxbits)
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throw "Invalid huffman";
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counts[p]++;
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}
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var code = 0;
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for (i in 1...maxbits - 1) {
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code = (code + counts[i]) << 1;
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tmp[i] = code;
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}
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var bits = new haxe.ds.IntMap();
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for (i in 0...nlengths) {
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var l = lengths[i + pos];
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if (l != 0) {
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var n = tmp[l - 1];
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tmp[l - 1] = n + 1;
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bits.set((n << 5) | l, i);
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}
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}
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return treeCompress(NeedBit(treeMake(bits, maxbits, 0, 1), treeMake(bits, maxbits, 1, 1)));
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}
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}
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