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https://github.com/20kdc/OC-KittenOS.git
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dcd7154ec2
This license change should only increase the amount of stuff people can do in countries where the public domain is not a valid concept. If this license somehow restricts you as opposed to the previous one, please file an issue.
292 lines
7.5 KiB
Lua
292 lines
7.5 KiB
Lua
-- Copyright (C) 2018-2021 by KittenOS NEO contributors
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--
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-- Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
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--
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-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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-- THIS SOFTWARE.
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-- THIS NEXT LINE IS CLEARLY AWFUL
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$bdBDWindow = nil
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-- THE DEFLATE DECOMPRESSOR OF MADNESS --
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-- Core I/O --
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-- $dfAlignToByteRemaining is
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-- set to 8 in the outer engine
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${
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function $dfGetIntField($L|lLen, $L|lVal)
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$lVal = 0
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for $L|lI = 0, $lLen - 1 do
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if coroutine.yield() then
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$lVal = $lVal + 2^$lI
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end
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end
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return $lVal
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end
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$}
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-- Huffman Core --
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-- The approach here is based around 1-prefixed integers.
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-- These are stored in a flat table.
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-- So 0b1000 is the pattern 000.
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${
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function $dfReadHuffmanSymbol($L|lTree, $L|lVal)
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$lVal = 1
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while not $lTree[$lVal] do
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$lVal = ($lVal * 2) + $dfGetIntField(1)
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end
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return $lTree[$lVal]
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end
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$}
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${
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function $dfGenHuffmanTree($L|lCodeLens)
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-- $L|lI (used everywhere; defining inside creates a bug because it gets globalized)
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$L|lNextCode = {}
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${
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-- To explain:
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-- lNextCode is needed all the way to the end.
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-- But lBLCount isn't needed after it's used to
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-- generate lNextCode.
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-- And lCode is very, very temporary.
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-- Hence this massive block.
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$L|lBLCount = {}
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-- Note the 0
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for $lI = 0, 15 do
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$lBLCount[$lI] = 0
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end
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for $lI = 0, #$lCodeLens do
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${
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$L|lCodeLen = $lCodeLens[$lI]
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if $lCodeLen ~= 0 then
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$lBLCount[$lCodeLen] = $lBLCount[$lCodeLen] + 1
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end
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$}
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end
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$L|lCode = 0
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for $lI = 1, 15 do
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$lCode = ($lCode + $lBLCount[$lI - 1]) * 2
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$lNextCode[$lI] = $lCode
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end
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$}
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$L|lTree = {}
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for $lI = 0, #$lCodeLens do
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${
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$L|lCodeLen = $lCodeLens[$lI]
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if $lCodeLen ~= 0 then
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$L|lPow = math.floor(2 ^ $lCodeLen)
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assert($lNextCode[$lCodeLen] < $lPow, "Tl" .. $lCodeLen)
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$L|lK = $lNextCode[$lCodeLen] + $lPow
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assert(not $lTree[$lK], "conflict @ " .. $lK)
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$lTree[$lK] = $lI
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$lNextCode[$lCodeLen] = $lNextCode[$lCodeLen] + 1
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end
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$}
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end
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return $lTree
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end
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$}
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-- DEFLATE fixed trees --
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${
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$L|dfFixedTL = {}
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for $L|lI = 0, 143 do $dfFixedTL[$lI] = 8 end
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for $lI = 144, 255 do $dfFixedTL[$lI] = 9 end
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for $lI = 256, 279 do $dfFixedTL[$lI] = 7 end
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for $lI = 280, 287 do $dfFixedTL[$lI] = 8 end
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$dfFixedLit = $dfGenHuffmanTree($dfFixedTL)
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-- last line possibly destroyed dfFixedTL, but that's alright
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$dfFixedTL = {}
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for $lI = 0, 31 do $dfFixedTL[$lI] = 5 end
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$dfFixedDst = $dfGenHuffmanTree($dfFixedTL)
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$}
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-- DEFLATE LZ Core --
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$dfWindow = ("\x00"):rep(2^15)
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$dfPushBuf = ""
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${
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function $dfOutput($L|lData)
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$dfWindow = ($dfWindow .. $lData):sub(-2^15)
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$dfPushBuf = $dfPushBuf .. $lData
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end
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$}
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$dfBittblLength = {
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0, 0, 0, 0, 0, 0, 0, 0,
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1, 1, 1, 1, 2, 2, 2, 2,
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3, 3, 3, 3, 4, 4, 4, 4,
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5, 5, 5, 5, 0
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}
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$dfBasetblLength = {
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3, 4, 5, 6, 7, 8, 9, 10,
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11, 13, 15, 17, 19, 23, 27, 31,
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35, 43, 51, 59, 67, 83, 99, 115,
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131, 163, 195, 227, 258
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}
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$dfBittblDist = {
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0, 0, 0, 0, 1, 1, 2, 2,
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3, 3, 4, 4, 5, 5, 6, 6,
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7, 7, 8, 8, 9, 9, 10, 10,
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11, 11, 12, 12, 13, 13
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}
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$dfBasetblDist = {
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1, 2, 3, 4, 5, 7, 9, 13,
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17, 25, 33, 49, 65, 97, 129, 193,
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257, 385, 513, 769, 1025, 1537, 2049, 3073,
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4097, 6145, 8193, 12289, 16385, 24577
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}
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${
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function $dfReadBlockBody($L|lLit, $L|lDst, $L|lLitSym, $L|lLen, $L|lDCode, $L|lPtr)
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while true do
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$lLitSym = $dfReadHuffmanSymbol($lLit)
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if $lLitSym <= 255 then
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$dfOutput(string.char($lLitSym))
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elseif $lLitSym == 256 then
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return
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elseif $lLitSym <= 285 then
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$lLen = $dfBasetblLength[$lLitSym - 256] + $dfGetIntField($dfBittblLength[$lLitSym - 256])
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$lDCode = $dfReadHuffmanSymbol($lDst)
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$lPtr = 32769 - ($dfBasetblDist[$lDCode + 1] + $dfGetIntField($dfBittblDist[$lDCode + 1]))
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for $L|lI = 1, $lLen do
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$dfOutput($dfWindow:sub($lPtr, $lPtr))
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end
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else
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error("nt" .. v)
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end
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end
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end
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$}
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-- Huffman Dynamics --
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${
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function $dfReadHuffmanDynamicSubcodes($L|lDistLens, $L|lCount, $L|lMetatree, $L|lCode)
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-- used a lot: $L|lI
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$lCode = 0
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$lDistLens[-1] = 0
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while $lCode < $lCount do
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-- use a tmpglb since it's just for the chain
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$L|lInstr = $dfReadHuffmanSymbol($lMetatree)
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if $lInstr < 16 then
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$lDistLens[$lCode] = $lInstr
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$lCode = $lCode + 1
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elseif $lInstr == 16 then
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for $lI = 1, 3 + $dfGetIntField(2) do
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$lDistLens[$lCode] = $lDistLens[$lCode - 1]
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$lCode = $lCode + 1
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assert($lCode <= $lCount, "sc.over")
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end
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elseif $lInstr == 17 then
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for $lI = 1, 3 + $dfGetIntField(3) do
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$lDistLens[$lCode] = 0
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$lCode = $lCode + 1
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assert($lCode <= $lCount, "sc.over")
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end
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elseif $lInstr == 18 then
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for $lI = 1, 11 + $dfGetIntField(7) do
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$lDistLens[$lCode] = 0
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$lCode = $lCode + 1
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assert($lCode <= $lCount, "sc.over")
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end
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else
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-- is this even possible?
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error("sc.unki")
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end
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end
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$lDistLens[-1] = nil
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return $lDistLens
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end
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$}
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$dfDynamicMetalensScramble = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}
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${
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function $dfReadHuffmanDynamic($L|lState, $L|lLiteralSize, $L|lDistanceSize, $L|lDistanceLens)
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-- $L|lI loop variable, used all over
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-- to save on locals, this is reused
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-- as metalens
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$lState = {}
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for $lI = 0, 18 do $lState[$lI] = 0 end
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$lLiteralSize = $dfGetIntField(5) + 257
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$lDistanceSize = $dfGetIntField(5) + 1
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for $lI = 1, $dfGetIntField(4) + 4 do
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$lState[$dfDynamicMetalensScramble[$lI]] = $dfGetIntField(3)
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end
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-- as metatree
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$lState = $dfGenHuffmanTree($lState)
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-- as concatenated subcodes
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$lState = $dfReadHuffmanDynamicSubcodes({}, $lLiteralSize + $lDistanceSize, $lState)
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-- The distance lengths are removed from lState,
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-- while being added to lDistanceLens
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-- The result is completion
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$lDistanceLens = {}
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for $lI = 0, $lDistanceSize - 1 do
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$lDistanceLens[$lI] = $lState[$lLiteralSize + $lI]
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$lState[$lLiteralSize + $lI] = nil
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end
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return $dfGenHuffmanTree($lState), $dfGenHuffmanTree($lDistanceLens)
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end
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$}
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-- Main Thread --
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${
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$dfThread = coroutine.create(function ($L|lFinal, $L|lLitLen)
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while true do
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$lFinal = coroutine.yield()
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$L|lBlockType = $dfGetIntField(2)
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if $lBlockType == 0 then
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-- literal
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$dfGetIntField($dfAlignToByteRemaining)
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$lLitLen = $dfGetIntField(16)
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-- this is weird, ignore it
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$dfGetIntField(16)
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for $L|lI = 1, $lLitLen do
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$dfOutput(string.char($dfGetIntField(8)))
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end
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elseif $lBlockType == 1 then
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-- fixed Huffman
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$dfReadBlockBody($dfFixedLit, $dfFixedDst)
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elseif $lBlockType == 2 then
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-- dynamic Huffman
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$dfReadBlockBody($dfReadHuffmanDynamic())
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else
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error("b3")
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end
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while $lFinal do
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coroutine.yield()
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end
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end
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end)
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$}
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-- The Outer Engine --
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coroutine.resume($dfThread)
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${
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function $engineInput($L|lData, $L|lByte)
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for $L|lI = 1, #$lData do
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$lByte = $lData:byte($lI)
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$dfAlignToByteRemaining = 8
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while $dfAlignToByteRemaining > 0 do
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-- If we're providing the first bit (v = 8), then there are 7 bits remaining.
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-- So this hits 0 when the *next* 8 yields will provide an as-is byte.
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$dfAlignToByteRemaining = $dfAlignToByteRemaining - 1
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assert(coroutine.resume($dfThread, $lByte % 2 == 1))
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$lByte = math.floor($lByte / 2)
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end
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end
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-- flush prepared buffer
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$engineOutput($dfPushBuf)
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$dfPushBuf = ""
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end
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$}
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