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<pre><a name="line-1"></a><span class='hs-comment'>-- arch-tag: Inflate implementation for Haskell</span>
<a name="line-2"></a>
<a name="line-3"></a><span class='hs-comment'>{-
<a name="line-4"></a>Inflate implementation for Haskell
<a name="line-5"></a>
<a name="line-6"></a>Copyright 2004 Ian Lynagh <igloo@earth.li>
<a name="line-7"></a>Licence: 3 clause BSD.
<a name="line-8"></a>
<a name="line-9"></a>\section{Inflate}
<a name="line-10"></a>
<a name="line-11"></a>This module provides a Haskell implementation of the inflate function,
<a name="line-12"></a>as described by RFC 1951.
<a name="line-13"></a>
<a name="line-14"></a>-}</span>
<a name="line-15"></a>
<a name="line-16"></a><span class='hs-comment'>{- |
<a name="line-17"></a> Module : Data.Compression.Inflate
<a name="line-18"></a> Copyright : Copyright (C) 2004 Ian Lynagh
<a name="line-19"></a> License : 3-clause BSD
<a name="line-20"></a>
<a name="line-21"></a> Maintainer : Ian Lynagh,
<a name="line-22"></a> Maintainer : <igloo@earth.li>
<a name="line-23"></a> Stability : provisional
<a name="line-24"></a> Portability: portable
<a name="line-25"></a>
<a name="line-26"></a>Inflate algorithm implementation
<a name="line-27"></a>
<a name="line-28"></a>Copyright (C) 2004 Ian Lynagh
<a name="line-29"></a>-}</span>
<a name="line-30"></a>
<a name="line-31"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Compression</span><span class='hs-varop'>.</span><span class='hs-conid'>Inflate</span> <span class='hs-layout'>(</span><span class='hs-varid'>inflate_string</span><span class='hs-layout'>,</span>
<a name="line-32"></a> <span class='hs-varid'>inflate_string_remainder</span><span class='hs-layout'>,</span>
<a name="line-33"></a> <span class='hs-varid'>inflate</span><span class='hs-layout'>,</span> <span class='hs-conid'>Output</span><span class='hs-layout'>,</span> <span class='hs-conid'>Bit</span><span class='hs-layout'>,</span>
<a name="line-34"></a> <span class='hs-varid'>bits_to_word32</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-35"></a>
<a name="line-36"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Array</span>
<a name="line-37"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span>
<a name="line-38"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Maybe</span>
<a name="line-39"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Char</span>
<a name="line-40"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span>
<a name="line-41"></a>
<a name="line-42"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Bits</span>
<a name="line-43"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Word</span>
<a name="line-44"></a>
<a name="line-45"></a><a name="inflate_string"></a><span class='hs-definition'>inflate_string</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span>
<a name="line-46"></a><span class='hs-definition'>inflate_string</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fst</span> <span class='hs-varop'>.</span> <span class='hs-varid'>inflate_string_remainder</span>
<a name="line-47"></a><span class='hs-comment'>-- map (Data.Char.chr . fromIntegral) $ fst $ inflate $ map Data.Char.ord s</span>
<a name="line-48"></a>
<a name="line-49"></a><a name="inflate_string_remainder"></a><span class='hs-comment'>-- | Returns (Data, Remainder)</span>
<a name="line-50"></a><span class='hs-definition'>inflate_string_remainder</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span> <span class='hs-conid'>String</span><span class='hs-layout'>)</span>
<a name="line-51"></a><span class='hs-definition'>inflate_string_remainder</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span>
<a name="line-52"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>res</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>inflate</span> <span class='hs-varop'>$</span> <span class='hs-varid'>map</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Char</span><span class='hs-varop'>.</span><span class='hs-varid'>ord</span> <span class='hs-varid'>s</span>
<a name="line-53"></a> <span class='hs-varid'>convw32l</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Char</span><span class='hs-varop'>.</span><span class='hs-varid'>chr</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fromIntegral</span><span class='hs-layout'>)</span> <span class='hs-varid'>l</span>
<a name="line-54"></a> <span class='hs-varid'>output</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>convw32l</span> <span class='hs-varop'>$</span> <span class='hs-varid'>fst</span> <span class='hs-varid'>res</span>
<a name="line-55"></a> <span class='hs-varid'>b2w32</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>[]</span>
<a name="line-56"></a> <span class='hs-varid'>b2w32</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>this</span><span class='hs-layout'>,</span> <span class='hs-varid'>next</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>splitAt</span> <span class='hs-num'>8</span> <span class='hs-varid'>b</span>
<a name="line-57"></a> <span class='hs-keyword'>in</span>
<a name="line-58"></a> <span class='hs-varid'>bits_to_word32</span> <span class='hs-varid'>this</span> <span class='hs-conop'>:</span> <span class='hs-varid'>b2w32</span> <span class='hs-varid'>next</span>
<a name="line-59"></a> <span class='hs-varid'>remainder</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>convw32l</span> <span class='hs-varop'>$</span> <span class='hs-varid'>b2w32</span> <span class='hs-varop'>$</span> <span class='hs-varid'>snd</span> <span class='hs-varid'>res</span>
<a name="line-60"></a> <span class='hs-keyword'>in</span>
<a name="line-61"></a> <span class='hs-layout'>(</span><span class='hs-varid'>output</span><span class='hs-layout'>,</span> <span class='hs-varid'>remainder</span><span class='hs-layout'>)</span>
<a name="line-62"></a>
<a name="line-63"></a><a name="Output"></a><span class='hs-comment'>{-
<a name="line-64"></a>\section{Types}
<a name="line-65"></a>
<a name="line-66"></a>Type synonyms are your friend.
<a name="line-67"></a>
<a name="line-68"></a>-}</span>
<a name="line-69"></a><a name="Output"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Output</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Word32</span><span class='hs-keyglyph'>]</span> <span class='hs-comment'>-- The final output</span>
<a name="line-70"></a>
<a name="line-71"></a><a name="Code"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Code</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Word32</span> <span class='hs-comment'>-- A generic code</span>
<a name="line-72"></a><a name="Dist"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Dist</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Code</span> <span class='hs-comment'>-- A distance code</span>
<a name="line-73"></a><a name="LitLen"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>LitLen</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Code</span> <span class='hs-comment'>-- A literal/length code</span>
<a name="line-74"></a><a name="Length"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Length</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Word32</span> <span class='hs-comment'>-- Number of bits needed to identify a code</span>
<a name="line-75"></a>
<a name="line-76"></a><a name="Table"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Table</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>Code</span> <span class='hs-comment'>-- A Huffman table</span>
<a name="line-77"></a><a name="Tables"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Tables</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>Table</span><span class='hs-layout'>,</span> <span class='hs-conid'>Table</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- lit/len and dist Huffman tables</span>
<a name="line-78"></a>
<a name="line-79"></a><a name="Bit"></a><span class='hs-comment'>{-
<a name="line-80"></a>
<a name="line-81"></a>The \verb!Bit! datatype is used for the input. We can show values and
<a name="line-82"></a>convert from the input we are given and to \verb!Word32!s which we us to
<a name="line-83"></a>represent most values.
<a name="line-84"></a>
<a name="line-85"></a>-}</span>
<a name="line-86"></a><a name="Bit"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>Bit</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Bit</span> <span class='hs-conid'>Bool</span>
<a name="line-87"></a> <span class='hs-keyword'>deriving</span> <span class='hs-conid'>Eq</span>
<a name="line-88"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Show</span> <span class='hs-conid'>Bit</span> <span class='hs-keyword'>where</span>
<a name="line-89"></a> <span class='hs-varid'>show</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>show_b</span>
<a name="line-90"></a> <span class='hs-varid'>showList</span> <span class='hs-varid'>bs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>showString</span> <span class='hs-varop'>$</span> <span class='hs-str'>"'"</span> <span class='hs-varop'>++</span> <span class='hs-varid'>map</span> <span class='hs-varid'>show_b</span> <span class='hs-varid'>bs</span> <span class='hs-varop'>++</span> <span class='hs-str'>"'"</span>
<a name="line-91"></a>
<a name="line-92"></a><a name="show_b"></a><span class='hs-definition'>show_b</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bit</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Char</span>
<a name="line-93"></a><span class='hs-definition'>show_b</span> <span class='hs-layout'>(</span><span class='hs-conid'>Bit</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-chr'>'1'</span>
<a name="line-94"></a><span class='hs-definition'>show_b</span> <span class='hs-layout'>(</span><span class='hs-conid'>Bit</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-chr'>'0'</span>
<a name="line-95"></a>
<a name="line-96"></a><a name="int_to_bits"></a><span class='hs-definition'>int_to_bits</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bit</span><span class='hs-keyglyph'>]</span>
<a name="line-97"></a><span class='hs-definition'>int_to_bits</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>word8_to_bits</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fromIntegral</span>
<a name="line-98"></a>
<a name="line-99"></a><a name="word8_to_bits"></a><span class='hs-definition'>word8_to_bits</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word8</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bit</span><span class='hs-keyglyph'>]</span>
<a name="line-100"></a><span class='hs-definition'>word8_to_bits</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bit</span> <span class='hs-layout'>(</span><span class='hs-varid'>testBit</span> <span class='hs-varid'>n</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>0</span><span class='hs-keyglyph'>..</span><span class='hs-num'>7</span><span class='hs-keyglyph'>]</span>
<a name="line-101"></a>
<a name="line-102"></a><a name="bits_to_word32"></a><span class='hs-definition'>bits_to_word32</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bit</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Word32</span>
<a name="line-103"></a><span class='hs-definition'>bits_to_word32</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldr</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-layout'>(</span><span class='hs-conid'>Bit</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-num'>2</span> <span class='hs-varop'>*</span> <span class='hs-varid'>i</span> <span class='hs-varop'>+</span> <span class='hs-layout'>(</span><span class='hs-keyword'>if</span> <span class='hs-varid'>b</span> <span class='hs-keyword'>then</span> <span class='hs-num'>1</span> <span class='hs-keyword'>else</span> <span class='hs-num'>0</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-num'>0</span>
<a name="line-104"></a>
<a name="line-105"></a><a name="State"></a><span class='hs-comment'>{-
<a name="line-106"></a>
<a name="line-107"></a>\section{Monad}
<a name="line-108"></a>
<a name="line-109"></a>offset is rarely used, so make it strict to avoid building huge closures.
<a name="line-110"></a>
<a name="line-111"></a>-}</span>
<a name="line-112"></a><a name="State"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>State</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>State</span> <span class='hs-layout'>{</span> <span class='hs-varid'>bits</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bit</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-comment'>-- remaining input bits</span>
<a name="line-113"></a> <span class='hs-varid'>offset</span> <span class='hs-keyglyph'>::</span> <span class='hs-varop'>!</span><span class='hs-conid'>Word32</span><span class='hs-layout'>,</span> <span class='hs-comment'>-- num bits consumed mod 8</span>
<a name="line-114"></a> <span class='hs-varid'>history</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Array</span> <span class='hs-conid'>Word32</span> <span class='hs-conid'>Word32</span><span class='hs-layout'>,</span> <span class='hs-comment'>-- last 32768 output words</span>
<a name="line-115"></a> <span class='hs-varid'>loc</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word32</span> <span class='hs-comment'>-- where in history we are</span>
<a name="line-116"></a> <span class='hs-layout'>}</span>
<a name="line-117"></a><a name="InfM"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>InfM</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>InfM</span> <span class='hs-layout'>(</span><span class='hs-conid'>State</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>State</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-118"></a>
<a name="line-119"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Monad</span> <span class='hs-conid'>InfM</span> <span class='hs-keyword'>where</span>
<a name="line-120"></a> <span class='hs-comment'>-- (>>=) :: InfM a -> (a -> InfM b) -> InfM b</span>
<a name="line-121"></a> <span class='hs-conid'>InfM</span> <span class='hs-varid'>v</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>InfM</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>v</span> <span class='hs-varid'>s</span>
<a name="line-122"></a> <span class='hs-conid'>InfM</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span>
<a name="line-123"></a> <span class='hs-keyword'>in</span> <span class='hs-varid'>y</span> <span class='hs-varid'>s'</span>
<a name="line-124"></a> <span class='hs-comment'>-- return :: a -> InfM a</span>
<a name="line-125"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>InfM</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-126"></a>
<a name="line-127"></a><a name="set_bits"></a><span class='hs-definition'>set_bits</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bit</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>()</span>
<a name="line-128"></a><span class='hs-definition'>set_bits</span> <span class='hs-varid'>bs</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>InfM</span> <span class='hs-varop'>$</span> <span class='hs-varid'>const</span> <span class='hs-layout'>(</span><span class='hs-conid'>()</span><span class='hs-layout'>,</span> <span class='hs-conid'>State</span> <span class='hs-varid'>bs</span> <span class='hs-num'>0</span> <span class='hs-layout'>(</span><span class='hs-varid'>array</span> <span class='hs-layout'>(</span><span class='hs-num'>0</span><span class='hs-layout'>,</span> <span class='hs-num'>32767</span><span class='hs-layout'>)</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span> <span class='hs-num'>0</span><span class='hs-layout'>)</span>
<a name="line-129"></a>
<a name="line-130"></a><span class='hs-comment'>{-
<a name="line-131"></a>no_bits :: InfM Bool
<a name="line-132"></a>no_bits = InfM $ \s -> (null (bits s), s)
<a name="line-133"></a>-}</span>
<a name="line-134"></a>
<a name="line-135"></a><a name="align_8_bits"></a><span class='hs-definition'>align_8_bits</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>()</span>
<a name="line-136"></a><span class='hs-definition'>align_8_bits</span>
<a name="line-137"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>InfM</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>()</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span> <span class='hs-layout'>{</span> <span class='hs-varid'>bits</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>genericDrop</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-num'>8</span> <span class='hs-comment'>-</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-varop'>`mod`</span> <span class='hs-num'>8</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>bits</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-138"></a> <span class='hs-varid'>offset</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>0</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-139"></a>
<a name="line-140"></a><a name="get_bits"></a><span class='hs-definition'>get_bits</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bit</span><span class='hs-keyglyph'>]</span>
<a name="line-141"></a><span class='hs-definition'>get_bits</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>InfM</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>need</span> <span class='hs-varid'>n</span> <span class='hs-layout'>(</span><span class='hs-varid'>bits</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span>
<a name="line-142"></a> <span class='hs-layout'>(</span><span class='hs-varid'>ys</span><span class='hs-layout'>,</span> <span class='hs-varid'>zs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-143"></a> <span class='hs-layout'>(</span><span class='hs-varid'>ys</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span> <span class='hs-layout'>{</span> <span class='hs-varid'>bits</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>zs</span><span class='hs-layout'>,</span>
<a name="line-144"></a> <span class='hs-varid'>offset</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>n</span> <span class='hs-varop'>+</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-varop'>`mod`</span> <span class='hs-num'>8</span> <span class='hs-layout'>}</span> <span class='hs-layout'>)</span>
<a name="line-145"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>need</span> <span class='hs-num'>0</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-146"></a> <span class='hs-varid'>need</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-str'>"get_bits: Don't have enough!"</span>
<a name="line-147"></a> <span class='hs-varid'>need</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>ys</span><span class='hs-layout'>,</span> <span class='hs-varid'>zs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>need</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-comment'>-</span><span class='hs-num'>1</span><span class='hs-layout'>)</span> <span class='hs-varid'>xs</span> <span class='hs-keyword'>in</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>ys</span><span class='hs-layout'>,</span> <span class='hs-varid'>zs</span><span class='hs-layout'>)</span>
<a name="line-148"></a>
<a name="line-149"></a><a name="extract_InfM"></a><span class='hs-definition'>extract_InfM</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>InfM</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bit</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-150"></a><span class='hs-definition'>extract_InfM</span> <span class='hs-layout'>(</span><span class='hs-conid'>InfM</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>undefined</span> <span class='hs-keyword'>in</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>bits</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-151"></a>
<a name="line-152"></a><a name="output_w32"></a><span class='hs-definition'>output_w32</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>()</span>
<a name="line-153"></a><span class='hs-definition'>output_w32</span> <span class='hs-varid'>w</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>InfM</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>let</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>loc</span> <span class='hs-varid'>s</span>
<a name="line-154"></a> <span class='hs-keyword'>in</span> <span class='hs-layout'>(</span><span class='hs-conid'>()</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span> <span class='hs-layout'>{</span> <span class='hs-varid'>history</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>history</span> <span class='hs-varid'>s</span> <span class='hs-varop'>//</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>l</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span>
<a name="line-155"></a> <span class='hs-varid'>loc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>l</span> <span class='hs-varop'>+</span> <span class='hs-num'>1</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-156"></a>
<a name="line-157"></a><a name="repeat_w32s"></a><span class='hs-definition'>repeat_w32s</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Word32</span><span class='hs-keyglyph'>]</span>
<a name="line-158"></a><span class='hs-definition'>repeat_w32s</span> <span class='hs-varid'>len</span> <span class='hs-varid'>dist</span>
<a name="line-159"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>InfM</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>let</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>loc</span> <span class='hs-varid'>s</span>
<a name="line-160"></a> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>history</span> <span class='hs-varid'>s</span>
<a name="line-161"></a> <span class='hs-varid'>new</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>h</span><span class='hs-varop'>!</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-varid'>genericTake</span> <span class='hs-varid'>dist</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>l</span> <span class='hs-comment'>-</span> <span class='hs-varid'>dist</span><span class='hs-layout'>)</span> <span class='hs-varop'>`mod`</span> <span class='hs-num'>32768</span><span class='hs-keyglyph'>..</span><span class='hs-num'>32767</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>0</span><span class='hs-keyglyph'>..</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-162"></a> <span class='hs-varid'>new_bit</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>genericTake</span> <span class='hs-varid'>len</span> <span class='hs-layout'>(</span><span class='hs-varid'>cycle</span> <span class='hs-varid'>new</span><span class='hs-layout'>)</span>
<a name="line-163"></a> <span class='hs-varid'>h'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>h</span> <span class='hs-varop'>//</span> <span class='hs-varid'>zip</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varop'>`mod`</span> <span class='hs-num'>32768</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>l</span><span class='hs-keyglyph'>..</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-varid'>new_bit</span>
<a name="line-164"></a> <span class='hs-keyword'>in</span> <span class='hs-layout'>(</span><span class='hs-varid'>new_bit</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span> <span class='hs-layout'>{</span> <span class='hs-varid'>history</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>h'</span><span class='hs-layout'>,</span> <span class='hs-varid'>loc</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>l</span> <span class='hs-varop'>+</span> <span class='hs-varid'>len</span><span class='hs-layout'>)</span> <span class='hs-varop'>`mod`</span> <span class='hs-num'>32768</span> <span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-165"></a>
<a name="line-166"></a><span class='hs-comment'>-----------------------------------</span>
<a name="line-167"></a>
<a name="line-168"></a><a name="get_word32s"></a><span class='hs-definition'>get_word32s</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Word32</span><span class='hs-keyglyph'>]</span>
<a name="line-169"></a><span class='hs-definition'>get_word32s</span> <span class='hs-keyword'>_</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-170"></a><span class='hs-definition'>get_word32s</span> <span class='hs-varid'>b</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>w</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_w32</span> <span class='hs-varid'>b</span>
<a name="line-171"></a> <span class='hs-varid'>ws</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_word32s</span> <span class='hs-varid'>b</span> <span class='hs-layout'>(</span><span class='hs-varid'>n</span><span class='hs-comment'>-</span><span class='hs-num'>1</span><span class='hs-layout'>)</span>
<a name="line-172"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>w</span><span class='hs-conop'>:</span><span class='hs-varid'>ws</span><span class='hs-layout'>)</span>
<a name="line-173"></a>
<a name="line-174"></a><a name="get_w32"></a><span class='hs-definition'>get_w32</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>Word32</span>
<a name="line-175"></a><span class='hs-definition'>get_w32</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>bs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_bits</span> <span class='hs-varid'>i</span>
<a name="line-176"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>bits_to_word32</span> <span class='hs-varid'>bs</span><span class='hs-layout'>)</span>
<a name="line-177"></a>
<a name="line-178"></a><a name="get_bit"></a><span class='hs-definition'>get_bit</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>Bit</span>
<a name="line-179"></a><span class='hs-definition'>get_bit</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_bits</span> <span class='hs-num'>1</span>
<a name="line-180"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>
<a name="line-181"></a>
<a name="line-182"></a><a name="inflate"></a><span class='hs-comment'>{-
<a name="line-183"></a>\section{Inflate itself}
<a name="line-184"></a>
<a name="line-185"></a>The hardcore stuff!
<a name="line-186"></a>
<a name="line-187"></a>-}</span>
<a name="line-188"></a><span class='hs-definition'>inflate</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Int</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Output</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bit</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-189"></a><span class='hs-definition'>inflate</span> <span class='hs-varid'>is</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>extract_InfM</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>set_bits</span> <span class='hs-varop'>$</span> <span class='hs-varid'>concatMap</span> <span class='hs-varid'>int_to_bits</span> <span class='hs-varid'>is</span>
<a name="line-190"></a> <span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>inflate_blocks</span> <span class='hs-conid'>False</span>
<a name="line-191"></a> <span class='hs-varid'>align_8_bits</span>
<a name="line-192"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>
<a name="line-193"></a>
<a name="line-194"></a><a name="inflate_blocks"></a><span class='hs-comment'>-- Bool is true if we have seen the "last" block</span>
<a name="line-195"></a><span class='hs-definition'>inflate_blocks</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>Output</span>
<a name="line-196"></a><span class='hs-definition'>inflate_blocks</span> <span class='hs-conid'>True</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-197"></a><span class='hs-definition'>inflate_blocks</span> <span class='hs-conid'>False</span>
<a name="line-198"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bit</span> <span class='hs-varid'>is_last</span><span class='hs-layout'>,</span> <span class='hs-conid'>Bit</span> <span class='hs-varid'>t1</span><span class='hs-layout'>,</span> <span class='hs-conid'>Bit</span> <span class='hs-varid'>t2</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_bits</span> <span class='hs-num'>3</span>
<a name="line-199"></a> <span class='hs-keyword'>case</span> <span class='hs-layout'>(</span><span class='hs-varid'>t1</span><span class='hs-layout'>,</span> <span class='hs-varid'>t2</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span>
<a name="line-200"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-201"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>align_8_bits</span>
<a name="line-202"></a> <span class='hs-varid'>len</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_w32</span> <span class='hs-num'>16</span>
<a name="line-203"></a> <span class='hs-varid'>nlen</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_w32</span> <span class='hs-num'>16</span>
<a name="line-204"></a> <span class='hs-varid'>unless</span> <span class='hs-layout'>(</span><span class='hs-varid'>len</span> <span class='hs-varop'>+</span> <span class='hs-varid'>nlen</span> <span class='hs-varop'>==</span> <span class='hs-num'>2</span><span class='hs-varop'>^</span><span class='hs-layout'>(</span><span class='hs-num'>32</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span><span class='hs-layout'>)</span> <span class='hs-comment'>-</span> <span class='hs-num'>1</span><span class='hs-layout'>)</span>
<a name="line-205"></a> <span class='hs-varop'>$</span> <span class='hs-varid'>error</span> <span class='hs-str'>"inflate_blocks: Mismatched lengths"</span>
<a name="line-206"></a> <span class='hs-varid'>ws</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_word32s</span> <span class='hs-num'>8</span> <span class='hs-varid'>len</span>
<a name="line-207"></a> <span class='hs-varid'>mapM_</span> <span class='hs-varid'>output_w32</span> <span class='hs-varid'>ws</span>
<a name="line-208"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>ws</span>
<a name="line-209"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-210"></a> <span class='hs-varid'>inflate_codes</span> <span class='hs-varid'>is_last</span> <span class='hs-varid'>inflate_trees_fixed</span>
<a name="line-211"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-212"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>tables</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>inflate_tables</span>
<a name="line-213"></a> <span class='hs-varid'>inflate_codes</span> <span class='hs-varid'>is_last</span> <span class='hs-varid'>tables</span>
<a name="line-214"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-215"></a> <span class='hs-varid'>error</span> <span class='hs-layout'>(</span><span class='hs-str'>"inflate_blocks: case 11 reserved"</span><span class='hs-layout'>)</span>
<a name="line-216"></a>
<a name="line-217"></a><a name="inflate_tables"></a><span class='hs-definition'>inflate_tables</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>Tables</span>
<a name="line-218"></a><span class='hs-definition'>inflate_tables</span>
<a name="line-219"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>hlit</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_w32</span> <span class='hs-num'>5</span>
<a name="line-220"></a> <span class='hs-varid'>hdist</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_w32</span> <span class='hs-num'>5</span>
<a name="line-221"></a> <span class='hs-varid'>hclen</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_w32</span> <span class='hs-num'>4</span>
<a name="line-222"></a> <span class='hs-varid'>llc_bs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_bits</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>hclen</span> <span class='hs-varop'>+</span> <span class='hs-num'>4</span><span class='hs-layout'>)</span> <span class='hs-varop'>*</span> <span class='hs-num'>3</span><span class='hs-layout'>)</span>
<a name="line-223"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>llc_bs'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>zip</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>bits_to_word32</span> <span class='hs-varop'>$</span> <span class='hs-varid'>triple</span> <span class='hs-varid'>llc_bs</span><span class='hs-layout'>)</span>
<a name="line-224"></a> <span class='hs-keyglyph'>[</span><span class='hs-num'>16</span><span class='hs-layout'>,</span><span class='hs-num'>17</span><span class='hs-layout'>,</span><span class='hs-num'>18</span><span class='hs-layout'>,</span><span class='hs-num'>0</span><span class='hs-layout'>,</span><span class='hs-num'>8</span><span class='hs-layout'>,</span><span class='hs-num'>7</span><span class='hs-layout'>,</span><span class='hs-num'>9</span><span class='hs-layout'>,</span><span class='hs-num'>6</span><span class='hs-layout'>,</span><span class='hs-num'>10</span><span class='hs-layout'>,</span><span class='hs-num'>5</span><span class='hs-layout'>,</span><span class='hs-num'>11</span><span class='hs-layout'>,</span><span class='hs-num'>4</span><span class='hs-layout'>,</span><span class='hs-num'>12</span><span class='hs-layout'>,</span><span class='hs-num'>3</span><span class='hs-layout'>,</span><span class='hs-num'>13</span><span class='hs-layout'>,</span><span class='hs-num'>2</span><span class='hs-layout'>,</span><span class='hs-num'>14</span><span class='hs-layout'>,</span><span class='hs-num'>1</span><span class='hs-layout'>,</span><span class='hs-num'>15</span><span class='hs-keyglyph'>]</span>
<a name="line-225"></a> <span class='hs-varid'>tab</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>make_table</span> <span class='hs-varid'>llc_bs'</span>
<a name="line-226"></a> <span class='hs-varid'>lit_dist_lengths</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>make_lit_dist_lengths</span> <span class='hs-varid'>tab</span>
<a name="line-227"></a> <span class='hs-layout'>(</span><span class='hs-num'>258</span> <span class='hs-varop'>+</span> <span class='hs-varid'>hlit</span> <span class='hs-varop'>+</span> <span class='hs-varid'>hdist</span><span class='hs-layout'>)</span>
<a name="line-228"></a> <span class='hs-layout'>(</span><span class='hs-varid'>error</span> <span class='hs-str'>"inflate_tables dummy"</span><span class='hs-layout'>)</span>
<a name="line-229"></a> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>lit_lengths</span><span class='hs-layout'>,</span> <span class='hs-varid'>dist_lengths</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>genericSplitAt</span> <span class='hs-layout'>(</span><span class='hs-num'>257</span> <span class='hs-varop'>+</span> <span class='hs-varid'>hlit</span><span class='hs-layout'>)</span>
<a name="line-230"></a> <span class='hs-varid'>lit_dist_lengths</span>
<a name="line-231"></a> <span class='hs-varid'>lit_table</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>make_table</span> <span class='hs-layout'>(</span><span class='hs-varid'>zip</span> <span class='hs-varid'>lit_lengths</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>0</span><span class='hs-keyglyph'>..</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-232"></a> <span class='hs-varid'>dist_table</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>make_table</span> <span class='hs-layout'>(</span><span class='hs-varid'>zip</span> <span class='hs-varid'>dist_lengths</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>0</span><span class='hs-keyglyph'>..</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-233"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>lit_table</span><span class='hs-layout'>,</span> <span class='hs-varid'>dist_table</span><span class='hs-layout'>)</span>
<a name="line-234"></a>
<a name="line-235"></a><a name="triple"></a><span class='hs-definition'>triple</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span>
<a name="line-236"></a><span class='hs-definition'>triple</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-conop'>:</span><span class='hs-varid'>b</span><span class='hs-conop'>:</span><span class='hs-varid'>c</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>b</span><span class='hs-layout'>,</span><span class='hs-varid'>c</span><span class='hs-keyglyph'>]</span><span class='hs-conop'>:</span><span class='hs-varid'>triple</span> <span class='hs-varid'>xs</span>
<a name="line-237"></a><span class='hs-definition'>triple</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>[]</span>
<a name="line-238"></a><span class='hs-definition'>triple</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-str'>"triple: can't happen"</span>
<a name="line-239"></a>
<a name="line-240"></a><a name="make_lit_dist_lengths"></a><span class='hs-definition'>make_lit_dist_lengths</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Table</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Word32</span><span class='hs-keyglyph'>]</span>
<a name="line-241"></a><span class='hs-definition'>make_lit_dist_lengths</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>i</span> <span class='hs-varop'><</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-str'>"make_lit_dist_lengths i < 0"</span>
<a name="line-242"></a><span class='hs-definition'>make_lit_dist_lengths</span> <span class='hs-keyword'>_</span> <span class='hs-num'>0</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-243"></a><span class='hs-definition'>make_lit_dist_lengths</span> <span class='hs-varid'>tab</span> <span class='hs-varid'>i</span> <span class='hs-varid'>last_thing</span>
<a name="line-244"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tab</span>
<a name="line-245"></a> <span class='hs-layout'>(</span><span class='hs-varid'>ls</span><span class='hs-layout'>,</span> <span class='hs-varid'>i'</span><span class='hs-layout'>,</span> <span class='hs-varid'>last_thing'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>meta_code</span> <span class='hs-varid'>i</span> <span class='hs-varid'>c</span> <span class='hs-varid'>last_thing</span>
<a name="line-246"></a> <span class='hs-varid'>ws</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>make_lit_dist_lengths</span> <span class='hs-varid'>tab</span> <span class='hs-varid'>i'</span> <span class='hs-varid'>last_thing'</span>
<a name="line-247"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>ls</span> <span class='hs-varop'>++</span> <span class='hs-varid'>ws</span><span class='hs-layout'>)</span>
<a name="line-248"></a>
<a name="line-249"></a><a name="meta_code"></a><span class='hs-definition'>meta_code</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Code</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>Word32</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-conid'>Word32</span><span class='hs-layout'>,</span> <span class='hs-conid'>Word32</span><span class='hs-layout'>)</span>
<a name="line-250"></a><span class='hs-definition'>meta_code</span> <span class='hs-varid'>c</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>i</span> <span class='hs-varop'><</span> <span class='hs-num'>16</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>i</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span> <span class='hs-comment'>-</span> <span class='hs-num'>1</span><span class='hs-layout'>,</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-251"></a><span class='hs-definition'>meta_code</span> <span class='hs-varid'>c</span> <span class='hs-num'>16</span> <span class='hs-varid'>last_thing</span>
<a name="line-252"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_bits</span> <span class='hs-num'>2</span>
<a name="line-253"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>3</span> <span class='hs-varop'>+</span> <span class='hs-varid'>bits_to_word32</span> <span class='hs-varid'>xs</span>
<a name="line-254"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>genericReplicate</span> <span class='hs-varid'>l</span> <span class='hs-varid'>last_thing</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span> <span class='hs-comment'>-</span> <span class='hs-varid'>l</span><span class='hs-layout'>,</span> <span class='hs-varid'>last_thing</span><span class='hs-layout'>)</span>
<a name="line-255"></a><span class='hs-definition'>meta_code</span> <span class='hs-varid'>c</span> <span class='hs-num'>17</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_bits</span> <span class='hs-num'>3</span>
<a name="line-256"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>3</span> <span class='hs-varop'>+</span> <span class='hs-varid'>bits_to_word32</span> <span class='hs-varid'>xs</span>
<a name="line-257"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>genericReplicate</span> <span class='hs-varid'>l</span> <span class='hs-num'>0</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span> <span class='hs-comment'>-</span> <span class='hs-varid'>l</span><span class='hs-layout'>,</span> <span class='hs-num'>0</span><span class='hs-layout'>)</span>
<a name="line-258"></a><span class='hs-definition'>meta_code</span> <span class='hs-varid'>c</span> <span class='hs-num'>18</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_bits</span> <span class='hs-num'>7</span>
<a name="line-259"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>11</span> <span class='hs-varop'>+</span> <span class='hs-varid'>bits_to_word32</span> <span class='hs-varid'>xs</span>
<a name="line-260"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>genericReplicate</span> <span class='hs-varid'>l</span> <span class='hs-num'>0</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span> <span class='hs-comment'>-</span> <span class='hs-varid'>l</span><span class='hs-layout'>,</span> <span class='hs-num'>0</span><span class='hs-layout'>)</span>
<a name="line-261"></a><span class='hs-definition'>meta_code</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-str'>"meta_code: "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>show</span> <span class='hs-varid'>i</span>
<a name="line-262"></a>
<a name="line-263"></a><a name="inflate_codes"></a><span class='hs-definition'>inflate_codes</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Tables</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>Output</span>
<a name="line-264"></a><span class='hs-definition'>inflate_codes</span> <span class='hs-varid'>seen_last</span> <span class='hs-varid'>tabs</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-varid'>tab_litlen</span><span class='hs-layout'>,</span> <span class='hs-varid'>tab_dist</span><span class='hs-layout'>)</span>
<a name="line-265"></a> <span class='hs-keyglyph'>=</span>
<a name="line-266"></a> <span class='hs-comment'>{- do done <- no_bits
<a name="line-267"></a> if done
<a name="line-268"></a> then return [] -- XXX Is this right?
<a name="line-269"></a> else -}</span>
<a name="line-270"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tab_litlen</span><span class='hs-layout'>;</span>
<a name="line-271"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>i</span> <span class='hs-varop'>==</span> <span class='hs-num'>256</span>
<a name="line-272"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>inflate_blocks</span> <span class='hs-varid'>seen_last</span>
<a name="line-273"></a> <span class='hs-keyword'>else</span>
<a name="line-274"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>pref</span> <span class='hs-keyglyph'><-</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>i</span> <span class='hs-varop'><</span> <span class='hs-num'>256</span>
<a name="line-275"></a> <span class='hs-keyword'>then</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>output_w32</span> <span class='hs-varid'>i</span>
<a name="line-276"></a> <span class='hs-varid'>return</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>i</span><span class='hs-keyglyph'>]</span>
<a name="line-277"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>lookup</span> <span class='hs-varid'>i</span> <span class='hs-varid'>litlens</span> <span class='hs-keyword'>of</span>
<a name="line-278"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>error</span> <span class='hs-str'>"do_code_litlen"</span>
<a name="line-279"></a> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>base</span><span class='hs-layout'>,</span> <span class='hs-varid'>num_bits</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-280"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>extra</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_w32</span> <span class='hs-varid'>num_bits</span>
<a name="line-281"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>base</span> <span class='hs-varop'>+</span> <span class='hs-varid'>extra</span>
<a name="line-282"></a> <span class='hs-varid'>dist</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>dist_code</span> <span class='hs-varid'>tab_dist</span>
<a name="line-283"></a> <span class='hs-varid'>repeat_w32s</span> <span class='hs-varid'>l</span> <span class='hs-varid'>dist</span>
<a name="line-284"></a> <span class='hs-varid'>o</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>inflate_codes</span> <span class='hs-varid'>seen_last</span> <span class='hs-varid'>tabs</span>
<a name="line-285"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>pref</span> <span class='hs-varop'>++</span> <span class='hs-varid'>o</span><span class='hs-layout'>)</span>
<a name="line-286"></a>
<a name="line-287"></a><a name="litlens"></a><span class='hs-definition'>litlens</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Code</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-conid'>LitLen</span><span class='hs-layout'>,</span> <span class='hs-conid'>Word32</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-288"></a><span class='hs-definition'>litlens</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>zip</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>257</span><span class='hs-keyglyph'>..</span><span class='hs-num'>285</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>$</span> <span class='hs-varid'>mk_bases</span> <span class='hs-num'>3</span> <span class='hs-varid'>litlen_counts</span> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-num'>258</span><span class='hs-layout'>,</span> <span class='hs-num'>0</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-289"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>litlen_counts</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-num'>8</span><span class='hs-layout'>,</span><span class='hs-num'>0</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span><span class='hs-layout'>(</span><span class='hs-num'>4</span><span class='hs-layout'>,</span><span class='hs-num'>1</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span><span class='hs-layout'>(</span><span class='hs-num'>4</span><span class='hs-layout'>,</span><span class='hs-num'>2</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span><span class='hs-layout'>(</span><span class='hs-num'>4</span><span class='hs-layout'>,</span><span class='hs-num'>3</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span><span class='hs-layout'>(</span><span class='hs-num'>4</span><span class='hs-layout'>,</span><span class='hs-num'>4</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span><span class='hs-layout'>(</span><span class='hs-num'>4</span><span class='hs-layout'>,</span><span class='hs-num'>5</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-290"></a>
<a name="line-291"></a><a name="dist_code"></a><span class='hs-definition'>dist_code</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Table</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>Dist</span>
<a name="line-292"></a><span class='hs-definition'>dist_code</span> <span class='hs-varid'>tab</span>
<a name="line-293"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>code</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>tab</span>
<a name="line-294"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>lookup</span> <span class='hs-varid'>code</span> <span class='hs-varid'>dists</span> <span class='hs-keyword'>of</span>
<a name="line-295"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>error</span> <span class='hs-str'>"dist_code"</span>
<a name="line-296"></a> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>base</span><span class='hs-layout'>,</span> <span class='hs-varid'>num_bits</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span> <span class='hs-varid'>extra</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_w32</span> <span class='hs-varid'>num_bits</span>
<a name="line-297"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>base</span> <span class='hs-varop'>+</span> <span class='hs-varid'>extra</span><span class='hs-layout'>)</span>
<a name="line-298"></a>
<a name="line-299"></a><a name="dists"></a><span class='hs-definition'>dists</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Code</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-conid'>Dist</span><span class='hs-layout'>,</span> <span class='hs-conid'>Word32</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-300"></a><span class='hs-definition'>dists</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>zip</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>0</span><span class='hs-keyglyph'>..</span><span class='hs-num'>29</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>$</span> <span class='hs-varid'>mk_bases</span> <span class='hs-num'>1</span> <span class='hs-varid'>dist_counts</span>
<a name="line-301"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>dist_counts</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-num'>4</span><span class='hs-layout'>,</span><span class='hs-num'>0</span><span class='hs-layout'>)</span><span class='hs-conop'>:</span><span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-conid'>(,)</span> <span class='hs-num'>2</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>1</span><span class='hs-keyglyph'>..</span><span class='hs-num'>13</span><span class='hs-keyglyph'>]</span>
<a name="line-302"></a>
<a name="line-303"></a><a name="mk_bases"></a><span class='hs-definition'>mk_bases</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Int</span><span class='hs-layout'>,</span> <span class='hs-conid'>Word32</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Word32</span><span class='hs-layout'>,</span> <span class='hs-conid'>Word32</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-304"></a><span class='hs-definition'>mk_bases</span> <span class='hs-varid'>base</span> <span class='hs-varid'>counts</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>snd</span> <span class='hs-varop'>$</span> <span class='hs-varid'>mapAccumL</span> <span class='hs-varid'>next_base</span> <span class='hs-varid'>base</span> <span class='hs-varid'>incs</span>
<a name="line-305"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>next_base</span> <span class='hs-varid'>current</span> <span class='hs-varid'>bs</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>current</span> <span class='hs-varop'>+</span> <span class='hs-num'>2</span><span class='hs-varop'>^</span><span class='hs-varid'>bs</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varid'>current</span><span class='hs-layout'>,</span> <span class='hs-varid'>bs</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-306"></a> <span class='hs-varid'>incs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>concat</span> <span class='hs-varop'>$</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>uncurry</span> <span class='hs-varid'>replicate</span><span class='hs-layout'>)</span> <span class='hs-varid'>counts</span>
<a name="line-307"></a>
<a name="line-308"></a><a name="inflate_trees_fixed"></a><span class='hs-comment'>{-
<a name="line-309"></a>\section{Fixed tables}
<a name="line-310"></a>
<a name="line-311"></a>The fixed tables. Not much to say really.
<a name="line-312"></a>
<a name="line-313"></a>-}</span>
<a name="line-314"></a><span class='hs-definition'>inflate_trees_fixed</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Tables</span>
<a name="line-315"></a><span class='hs-definition'>inflate_trees_fixed</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>make_table</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-num'>8</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>0</span><span class='hs-keyglyph'>..</span><span class='hs-num'>143</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span>
<a name="line-316"></a> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-num'>9</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>144</span><span class='hs-keyglyph'>..</span><span class='hs-num'>255</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span>
<a name="line-317"></a> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-num'>7</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>256</span><span class='hs-keyglyph'>..</span><span class='hs-num'>279</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span>
<a name="line-318"></a> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-num'>8</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>280</span><span class='hs-keyglyph'>..</span><span class='hs-num'>287</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span>
<a name="line-319"></a> <span class='hs-varid'>make_table</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-num'>5</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>0</span><span class='hs-keyglyph'>..</span><span class='hs-num'>29</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-320"></a>
<a name="line-321"></a><a name="Tree"></a><span class='hs-comment'>{-
<a name="line-322"></a>\section{The Huffman Tree}
<a name="line-323"></a>
<a name="line-324"></a>As the name suggests, the obvious way to store Huffman trees is in a
<a name="line-325"></a>tree datastructure. Externally we want to view them as functions though,
<a name="line-326"></a>so we wrap the tree with \verb!get_code! which takes a list of bits and
<a name="line-327"></a>returns the corresponding code and the remaining bits. To make a tree
<a name="line-328"></a>from a list of length code pairs is a simple recursive process.
<a name="line-329"></a>
<a name="line-330"></a>-}</span>
<a name="line-331"></a><a name="Tree"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>Tree</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-conid'>Tree</span> <span class='hs-conid'>Tree</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Leaf</span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Null</span>
<a name="line-332"></a>
<a name="line-333"></a><a name="make_table"></a><span class='hs-definition'>make_table</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Length</span><span class='hs-layout'>,</span> <span class='hs-conid'>Code</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Table</span>
<a name="line-334"></a><span class='hs-definition'>make_table</span> <span class='hs-varid'>lcs</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>make_tree</span> <span class='hs-num'>0</span> <span class='hs-varop'>$</span> <span class='hs-varid'>sort</span> <span class='hs-varop'>$</span> <span class='hs-varid'>filter</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>/=</span> <span class='hs-num'>0</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fst</span><span class='hs-layout'>)</span> <span class='hs-varid'>lcs</span> <span class='hs-keyword'>of</span>
<a name="line-335"></a> <span class='hs-layout'>(</span><span class='hs-varid'>tree</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>get_code</span> <span class='hs-varid'>tree</span>
<a name="line-336"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-str'>"make_table: Left-over lcs from"</span>
<a name="line-337"></a>
<a name="line-338"></a><a name="get_code"></a><span class='hs-definition'>get_code</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Tree</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>InfM</span> <span class='hs-conid'>Code</span>
<a name="line-339"></a><span class='hs-definition'>get_code</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>zero_tree</span> <span class='hs-varid'>one_tree</span><span class='hs-layout'>)</span>
<a name="line-340"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-conid'>Bit</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get_bit</span>
<a name="line-341"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>b</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>get_code</span> <span class='hs-varid'>one_tree</span> <span class='hs-keyword'>else</span> <span class='hs-varid'>get_code</span> <span class='hs-varid'>zero_tree</span>
<a name="line-342"></a><span class='hs-definition'>get_code</span> <span class='hs-layout'>(</span><span class='hs-conid'>Leaf</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varid'>w</span>
<a name="line-343"></a><span class='hs-definition'>get_code</span> <span class='hs-conid'>Null</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-str'>"get_code Null"</span>
<a name="line-344"></a>
<a name="line-345"></a><a name="make_tree"></a><span class='hs-definition'>make_tree</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word32</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Length</span><span class='hs-layout'>,</span> <span class='hs-conid'>Code</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Tree</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Length</span><span class='hs-layout'>,</span> <span class='hs-conid'>Code</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-346"></a><span class='hs-definition'>make_tree</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>Null</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-347"></a><span class='hs-definition'>make_tree</span> <span class='hs-varid'>i</span> <span class='hs-varid'>lcs</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>l</span><span class='hs-layout'>,</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span><span class='hs-conop'>:</span><span class='hs-varid'>lcs'</span><span class='hs-layout'>)</span>
<a name="line-348"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>i</span> <span class='hs-varop'>==</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>Leaf</span> <span class='hs-varid'>c</span><span class='hs-layout'>,</span> <span class='hs-varid'>lcs'</span><span class='hs-layout'>)</span>
<a name="line-349"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>i</span> <span class='hs-varop'><</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>zero_tree</span><span class='hs-layout'>,</span> <span class='hs-varid'>lcs_z</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>make_tree</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-varop'>+</span><span class='hs-num'>1</span><span class='hs-layout'>)</span> <span class='hs-varid'>lcs</span>
<a name="line-350"></a> <span class='hs-layout'>(</span><span class='hs-varid'>one_tree</span><span class='hs-layout'>,</span> <span class='hs-varid'>lcs_o</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>make_tree</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-varop'>+</span><span class='hs-num'>1</span><span class='hs-layout'>)</span> <span class='hs-varid'>lcs_z</span>
<a name="line-351"></a> <span class='hs-keyword'>in</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>zero_tree</span> <span class='hs-varid'>one_tree</span><span class='hs-layout'>,</span> <span class='hs-varid'>lcs_o</span><span class='hs-layout'>)</span>
<a name="line-352"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-str'>"make_tree: can't happen"</span>
<a name="line-353"></a>
<a name="line-354"></a>
</pre></body>
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