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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE CPP #-}</span>
<a name="line-2"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-3"></a><span class='hs-comment'>-- |</span>
<a name="line-4"></a><span class='hs-comment'>-- Copyright : (c) 2006-2008 Duncan Coutts</span>
<a name="line-5"></a><span class='hs-comment'>-- License : BSD-style</span>
<a name="line-6"></a><span class='hs-comment'>--</span>
<a name="line-7"></a><span class='hs-comment'>-- Maintainer : duncan@haskell.org</span>
<a name="line-8"></a><span class='hs-comment'>-- Stability : provisional</span>
<a name="line-9"></a><span class='hs-comment'>-- Portability : portable (H98 + FFI)</span>
<a name="line-10"></a><span class='hs-comment'>--</span>
<a name="line-11"></a><span class='hs-comment'>-- Pure stream based interface to lower level zlib wrapper</span>
<a name="line-12"></a><span class='hs-comment'>--</span>
<a name="line-13"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-14"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Codec</span><span class='hs-varop'>.</span><span class='hs-conid'>Compression</span><span class='hs-varop'>.</span><span class='hs-conid'>Zlib</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span> <span class='hs-layout'>(</span>
<a name="line-15"></a>
<a name="line-16"></a> <span class='hs-comment'>-- * Compression</span>
<a name="line-17"></a> <span class='hs-varid'>compress</span><span class='hs-layout'>,</span>
<a name="line-18"></a> <span class='hs-conid'>CompressParams</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-19"></a> <span class='hs-varid'>defaultCompressParams</span><span class='hs-layout'>,</span>
<a name="line-20"></a>
<a name="line-21"></a> <span class='hs-comment'>-- * Decompression</span>
<a name="line-22"></a> <span class='hs-varid'>decompress</span><span class='hs-layout'>,</span>
<a name="line-23"></a> <span class='hs-conid'>DecompressParams</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-24"></a> <span class='hs-varid'>defaultDecompressParams</span><span class='hs-layout'>,</span>
<a name="line-25"></a>
<a name="line-26"></a> <span class='hs-comment'>-- * The compression parameter types</span>
<a name="line-27"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Format</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-28"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>gzipFormat</span><span class='hs-layout'>,</span>
<a name="line-29"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>zlibFormat</span><span class='hs-layout'>,</span>
<a name="line-30"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>rawFormat</span><span class='hs-layout'>,</span>
<a name="line-31"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>gzipOrZlibFormat</span><span class='hs-layout'>,</span>
<a name="line-32"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>CompressionLevel</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-33"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>defaultCompression</span><span class='hs-layout'>,</span>
<a name="line-34"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>noCompression</span><span class='hs-layout'>,</span>
<a name="line-35"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>bestSpeed</span><span class='hs-layout'>,</span>
<a name="line-36"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>bestCompression</span><span class='hs-layout'>,</span>
<a name="line-37"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>compressionLevel</span><span class='hs-layout'>,</span>
<a name="line-38"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Method</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-39"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>deflateMethod</span><span class='hs-layout'>,</span>
<a name="line-40"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>WindowBits</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-41"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>defaultWindowBits</span><span class='hs-layout'>,</span>
<a name="line-42"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>windowBits</span><span class='hs-layout'>,</span>
<a name="line-43"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>MemoryLevel</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-44"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>defaultMemoryLevel</span><span class='hs-layout'>,</span>
<a name="line-45"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>minMemoryLevel</span><span class='hs-layout'>,</span>
<a name="line-46"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>maxMemoryLevel</span><span class='hs-layout'>,</span>
<a name="line-47"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>memoryLevel</span><span class='hs-layout'>,</span>
<a name="line-48"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>CompressionStrategy</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-49"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>defaultStrategy</span><span class='hs-layout'>,</span>
<a name="line-50"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>filteredStrategy</span><span class='hs-layout'>,</span>
<a name="line-51"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>huffmanOnlyStrategy</span><span class='hs-layout'>,</span>
<a name="line-52"></a>
<a name="line-53"></a> <span class='hs-comment'>-- * Low-level API to get explicit error reports</span>
<a name="line-54"></a> <span class='hs-varid'>decompressWithErrors</span><span class='hs-layout'>,</span>
<a name="line-55"></a> <span class='hs-conid'>DecompressStream</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-56"></a> <span class='hs-conid'>DecompressError</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-57"></a> <span class='hs-varid'>foldDecompressStream</span><span class='hs-layout'>,</span>
<a name="line-58"></a> <span class='hs-varid'>fromDecompressStream</span><span class='hs-layout'>,</span>
<a name="line-59"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-60"></a>
<a name="line-61"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Prelude</span> <span class='hs-varid'>hiding</span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span><span class='hs-layout'>)</span>
<a name="line-62"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-varid'>when</span><span class='hs-layout'>)</span>
<a name="line-63"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Exception</span> <span class='hs-layout'>(</span><span class='hs-varid'>assert</span><span class='hs-layout'>)</span>
<a name="line-64"></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'>ByteString</span><span class='hs-varop'>.</span><span class='hs-conid'>Lazy</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>L</span>
<a name="line-65"></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'>ByteString</span><span class='hs-varop'>.</span><span class='hs-conid'>Lazy</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>L</span>
<a name="line-66"></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'>ByteString</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>S</span>
<a name="line-67"></a>
<a name="line-68"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Codec</span><span class='hs-varop'>.</span><span class='hs-conid'>Compression</span><span class='hs-varop'>.</span><span class='hs-conid'>Zlib</span><span class='hs-varop'>.</span><span class='hs-conid'>Stream</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>Stream</span>
<a name="line-69"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Codec</span><span class='hs-varop'>.</span><span class='hs-conid'>Compression</span><span class='hs-varop'>.</span><span class='hs-conid'>Zlib</span><span class='hs-varop'>.</span><span class='hs-conid'>Stream</span> <span class='hs-layout'>(</span><span class='hs-conid'>Stream</span><span class='hs-layout'>)</span>
<a name="line-70"></a>
<a name="line-71"></a><a name="CompressParams"></a><span class='hs-comment'>-- | The full set of parameters for compression. The defaults are</span>
<a name="line-72"></a><a name="CompressParams"></a><span class='hs-comment'>-- 'defaultCompressParams'.</span>
<a name="line-73"></a><a name="CompressParams"></a><span class='hs-comment'>--</span>
<a name="line-74"></a><a name="CompressParams"></a><span class='hs-comment'>-- The 'compressBufferSize' is the size of the first output buffer containing</span>
<a name="line-75"></a><a name="CompressParams"></a><span class='hs-comment'>-- the compressed data. If you know an approximate upper bound on the size of</span>
<a name="line-76"></a><a name="CompressParams"></a><span class='hs-comment'>-- the compressed data then setting this parameter can save memory. The default</span>
<a name="line-77"></a><a name="CompressParams"></a><span class='hs-comment'>-- compression output buffer size is @16k@. If your extimate is wrong it does</span>
<a name="line-78"></a><a name="CompressParams"></a><span class='hs-comment'>-- not matter too much, the default buffer size will be used for the remaining</span>
<a name="line-79"></a><a name="CompressParams"></a><span class='hs-comment'>-- chunks.</span>
<a name="line-80"></a><a name="CompressParams"></a><span class='hs-comment'>--</span>
<a name="line-81"></a><a name="CompressParams"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>CompressParams</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>CompressParams</span> <span class='hs-layout'>{</span>
<a name="line-82"></a> <span class='hs-varid'>compressLevel</span> <span class='hs-keyglyph'>::</span> <span class='hs-varop'>!</span><span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>CompressionLevel</span><span class='hs-layout'>,</span>
<a name="line-83"></a> <span class='hs-varid'>compressMethod</span> <span class='hs-keyglyph'>::</span> <span class='hs-varop'>!</span><span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Method</span><span class='hs-layout'>,</span>
<a name="line-84"></a> <span class='hs-varid'>compressWindowBits</span> <span class='hs-keyglyph'>::</span> <span class='hs-varop'>!</span><span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>WindowBits</span><span class='hs-layout'>,</span>
<a name="line-85"></a> <span class='hs-varid'>compressMemoryLevel</span> <span class='hs-keyglyph'>::</span> <span class='hs-varop'>!</span><span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>MemoryLevel</span><span class='hs-layout'>,</span>
<a name="line-86"></a> <span class='hs-varid'>compressStrategy</span> <span class='hs-keyglyph'>::</span> <span class='hs-varop'>!</span><span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>CompressionStrategy</span><span class='hs-layout'>,</span>
<a name="line-87"></a> <span class='hs-varid'>compressBufferSize</span> <span class='hs-keyglyph'>::</span> <span class='hs-varop'>!</span><span class='hs-conid'>Int</span>
<a name="line-88"></a><span class='hs-layout'>}</span>
<a name="line-89"></a>
<a name="line-90"></a><a name="DecompressParams"></a><span class='hs-comment'>-- | The full set of parameters for decompression. The defaults are</span>
<a name="line-91"></a><a name="DecompressParams"></a><span class='hs-comment'>-- 'defaultDecompressParams'.</span>
<a name="line-92"></a><a name="DecompressParams"></a><span class='hs-comment'>--</span>
<a name="line-93"></a><a name="DecompressParams"></a><span class='hs-comment'>-- The 'decompressBufferSize' is the size of the first output buffer,</span>
<a name="line-94"></a><a name="DecompressParams"></a><span class='hs-comment'>-- containing the uncompressed data. If you know an exact or approximate upper</span>
<a name="line-95"></a><a name="DecompressParams"></a><span class='hs-comment'>-- bound on the size of the decompressed data then setting this parameter can</span>
<a name="line-96"></a><a name="DecompressParams"></a><span class='hs-comment'>-- save memory. The default decompression output buffer size is @32k@. If your</span>
<a name="line-97"></a><a name="DecompressParams"></a><span class='hs-comment'>-- extimate is wrong it does not matter too much, the default buffer size will</span>
<a name="line-98"></a><a name="DecompressParams"></a><span class='hs-comment'>-- be used for the remaining chunks.</span>
<a name="line-99"></a><a name="DecompressParams"></a><span class='hs-comment'>--</span>
<a name="line-100"></a><a name="DecompressParams"></a><span class='hs-comment'>-- One particular use case for setting the 'decompressBufferSize' is if you</span>
<a name="line-101"></a><a name="DecompressParams"></a><span class='hs-comment'>-- know the exact size of the decompressed data and want to produce a strict</span>
<a name="line-102"></a><a name="DecompressParams"></a><span class='hs-comment'>-- 'Data.ByteString.ByteString'. The compression and deccompression functions</span>
<a name="line-103"></a><a name="DecompressParams"></a><span class='hs-comment'>-- use lazy 'Data.ByteString.Lazy.ByteString's but if you set the</span>
<a name="line-104"></a><a name="DecompressParams"></a><span class='hs-comment'>-- 'decompressBufferSize' correctly then you can generate a lazy</span>
<a name="line-105"></a><a name="DecompressParams"></a><span class='hs-comment'>-- 'Data.ByteString.Lazy.ByteString' with exactly one chunk, which can be</span>
<a name="line-106"></a><a name="DecompressParams"></a><span class='hs-comment'>-- converted to a strict 'Data.ByteString.ByteString' in @O(1)@ time using</span>
<a name="line-107"></a><a name="DecompressParams"></a><span class='hs-comment'>-- @'Data.ByteString.concat' . 'Data.ByteString.Lazy.toChunks'@.</span>
<a name="line-108"></a><a name="DecompressParams"></a><span class='hs-comment'>--</span>
<a name="line-109"></a><a name="DecompressParams"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>DecompressParams</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>DecompressParams</span> <span class='hs-layout'>{</span>
<a name="line-110"></a> <span class='hs-varid'>decompressWindowBits</span> <span class='hs-keyglyph'>::</span> <span class='hs-varop'>!</span><span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>WindowBits</span><span class='hs-layout'>,</span>
<a name="line-111"></a> <span class='hs-varid'>decompressBufferSize</span> <span class='hs-keyglyph'>::</span> <span class='hs-varop'>!</span><span class='hs-conid'>Int</span>
<a name="line-112"></a><span class='hs-layout'>}</span>
<a name="line-113"></a>
<a name="line-114"></a><a name="defaultCompressParams"></a><span class='hs-comment'>-- | The default set of parameters for compression. This is typically used with</span>
<a name="line-115"></a><span class='hs-comment'>-- the @compressWith@ function with specific parameters overridden.</span>
<a name="line-116"></a><span class='hs-comment'>--</span>
<a name="line-117"></a><span class='hs-definition'>defaultCompressParams</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>CompressParams</span>
<a name="line-118"></a><span class='hs-definition'>defaultCompressParams</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>CompressParams</span> <span class='hs-layout'>{</span>
<a name="line-119"></a> <span class='hs-varid'>compressLevel</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>defaultCompression</span><span class='hs-layout'>,</span>
<a name="line-120"></a> <span class='hs-varid'>compressMethod</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>deflateMethod</span><span class='hs-layout'>,</span>
<a name="line-121"></a> <span class='hs-varid'>compressWindowBits</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>defaultWindowBits</span><span class='hs-layout'>,</span>
<a name="line-122"></a> <span class='hs-varid'>compressMemoryLevel</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>defaultMemoryLevel</span><span class='hs-layout'>,</span>
<a name="line-123"></a> <span class='hs-varid'>compressStrategy</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>defaultStrategy</span><span class='hs-layout'>,</span>
<a name="line-124"></a> <span class='hs-varid'>compressBufferSize</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>defaultCompressBufferSize</span>
<a name="line-125"></a><span class='hs-layout'>}</span>
<a name="line-126"></a>
<a name="line-127"></a><a name="defaultDecompressParams"></a><span class='hs-comment'>-- | The default set of parameters for decompression. This is typically used with</span>
<a name="line-128"></a><span class='hs-comment'>-- the @compressWith@ function with specific parameters overridden.</span>
<a name="line-129"></a><span class='hs-comment'>--</span>
<a name="line-130"></a><span class='hs-definition'>defaultDecompressParams</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>DecompressParams</span>
<a name="line-131"></a><span class='hs-definition'>defaultDecompressParams</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>DecompressParams</span> <span class='hs-layout'>{</span>
<a name="line-132"></a> <span class='hs-varid'>decompressWindowBits</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>defaultWindowBits</span><span class='hs-layout'>,</span>
<a name="line-133"></a> <span class='hs-varid'>decompressBufferSize</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>defaultDecompressBufferSize</span>
<a name="line-134"></a><span class='hs-layout'>}</span>
<a name="line-135"></a>
<a name="line-136"></a><a name="defaultCompressBufferSize"></a><span class='hs-comment'>-- | The default chunk sizes for the output of compression and decompression</span>
<a name="line-137"></a><span class='hs-comment'>-- are 16k and 32k respectively (less a small accounting overhead).</span>
<a name="line-138"></a><span class='hs-comment'>--</span>
<a name="line-139"></a><span class='hs-definition'>defaultCompressBufferSize</span><span class='hs-layout'>,</span> <span class='hs-varid'>defaultDecompressBufferSize</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span>
<a name="line-140"></a><span class='hs-definition'>defaultCompressBufferSize</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>16</span> <span class='hs-varop'>*</span> <span class='hs-num'>1024</span> <span class='hs-comment'>-</span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-varid'>chunkOverhead</span>
<a name="line-141"></a><a name="defaultDecompressBufferSize"></a><span class='hs-definition'>defaultDecompressBufferSize</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>32</span> <span class='hs-varop'>*</span> <span class='hs-num'>1024</span> <span class='hs-comment'>-</span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-varid'>chunkOverhead</span>
<a name="line-142"></a>
<a name="line-143"></a><a name="DecompressStream"></a><span class='hs-comment'>-- | A sequence of chunks of data produced from decompression.</span>
<a name="line-144"></a><a name="DecompressStream"></a><span class='hs-comment'>--</span>
<a name="line-145"></a><a name="DecompressStream"></a><span class='hs-comment'>-- The difference from a simple list is that it contains a representation of</span>
<a name="line-146"></a><a name="DecompressStream"></a><span class='hs-comment'>-- errors as data rather than as exceptions. This allows you to handle error</span>
<a name="line-147"></a><a name="DecompressStream"></a><span class='hs-comment'>-- conditions explicitly.</span>
<a name="line-148"></a><a name="DecompressStream"></a><span class='hs-comment'>--</span>
<a name="line-149"></a><a name="DecompressStream"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>DecompressStream</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>StreamEnd</span>
<a name="line-150"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>StreamChunk</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span> <span class='hs-conid'>DecompressStream</span>
<a name="line-151"></a>
<a name="line-152"></a> <span class='hs-comment'>-- | An error code and a human readable error message.</span>
<a name="line-153"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>StreamError</span> <span class='hs-conid'>DecompressError</span> <span class='hs-conid'>String</span>
<a name="line-154"></a>
<a name="line-155"></a><a name="DecompressError"></a><span class='hs-comment'>-- | The possible error cases when decompressing a stream.</span>
<a name="line-156"></a><a name="DecompressError"></a><span class='hs-comment'>--</span>
<a name="line-157"></a><a name="DecompressError"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>DecompressError</span> <span class='hs-keyglyph'>=</span>
<a name="line-158"></a> <span class='hs-comment'>-- | The compressed data stream ended prematurely. This may happen if the</span>
<a name="line-159"></a> <span class='hs-comment'>-- input data stream was truncated.</span>
<a name="line-160"></a> <span class='hs-conid'>TruncatedInput</span>
<a name="line-161"></a>
<a name="line-162"></a> <span class='hs-comment'>-- | It is possible to do zlib compression with a custom dictionary. This</span>
<a name="line-163"></a> <span class='hs-comment'>-- allows slightly higher compression ratios for short files. However such</span>
<a name="line-164"></a> <span class='hs-comment'>-- compressed streams require the same dictionary when decompressing. This</span>
<a name="line-165"></a> <span class='hs-comment'>-- zlib binding does not currently support custom dictionaries. This error</span>
<a name="line-166"></a> <span class='hs-comment'>-- is for when we encounter a compressed stream that needs a dictionary.</span>
<a name="line-167"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>DictionaryRequired</span>
<a name="line-168"></a>
<a name="line-169"></a> <span class='hs-comment'>-- | If the compressed data stream is corrupted in any way then you will</span>
<a name="line-170"></a> <span class='hs-comment'>-- get this error, for example if the input data just isn't a compressed</span>
<a name="line-171"></a> <span class='hs-comment'>-- zlib data stream. In particular if the data checksum turns out to be</span>
<a name="line-172"></a> <span class='hs-comment'>-- wrong then you will get all the decompressed data but this error at the</span>
<a name="line-173"></a> <span class='hs-comment'>-- end, instead of the normal sucessful 'StreamEnd'.</span>
<a name="line-174"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>DataError</span>
<a name="line-175"></a>
<a name="line-176"></a><a name="foldDecompressStream"></a><span class='hs-comment'>-- | Fold an 'DecompressionStream'. Just like 'foldr' but with an extra error</span>
<a name="line-177"></a><span class='hs-comment'>-- case. For example to convert to a list and translate the errors into</span>
<a name="line-178"></a><span class='hs-comment'>-- exceptions:</span>
<a name="line-179"></a><span class='hs-comment'>--</span>
<a name="line-180"></a><span class='hs-comment'>-- > foldDecompressStream (:) [] (\code msg -> error msg)</span>
<a name="line-181"></a><span class='hs-comment'>--</span>
<a name="line-182"></a><span class='hs-definition'>foldDecompressStream</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span>
<a name="line-183"></a> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>DecompressError</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-184"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>DecompressStream</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span>
<a name="line-185"></a><span class='hs-definition'>foldDecompressStream</span> <span class='hs-varid'>chunk</span> <span class='hs-varid'>end</span> <span class='hs-varid'>err</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fold</span>
<a name="line-186"></a> <span class='hs-keyword'>where</span>
<a name="line-187"></a> <span class='hs-varid'>fold</span> <span class='hs-conid'>StreamEnd</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>end</span>
<a name="line-188"></a> <span class='hs-varid'>fold</span> <span class='hs-layout'>(</span><span class='hs-conid'>StreamChunk</span> <span class='hs-varid'>bs</span> <span class='hs-varid'>stream</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>chunk</span> <span class='hs-varid'>bs</span> <span class='hs-layout'>(</span><span class='hs-varid'>fold</span> <span class='hs-varid'>stream</span><span class='hs-layout'>)</span>
<a name="line-189"></a> <span class='hs-varid'>fold</span> <span class='hs-layout'>(</span><span class='hs-conid'>StreamError</span> <span class='hs-varid'>code</span> <span class='hs-varid'>msg</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>err</span> <span class='hs-varid'>code</span> <span class='hs-varid'>msg</span>
<a name="line-190"></a>
<a name="line-191"></a><a name="fromDecompressStream"></a><span class='hs-comment'>-- | Convert a 'DecompressStream' to a lazy 'ByteString'. If any decompression</span>
<a name="line-192"></a><span class='hs-comment'>-- errors are encountered then they are thrown as exceptions.</span>
<a name="line-193"></a><span class='hs-comment'>--</span>
<a name="line-194"></a><span class='hs-comment'>-- This is a special case of 'foldDecompressStream'.</span>
<a name="line-195"></a><span class='hs-comment'>--</span>
<a name="line-196"></a><span class='hs-definition'>fromDecompressStream</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>DecompressStream</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span>
<a name="line-197"></a><span class='hs-definition'>fromDecompressStream</span> <span class='hs-keyglyph'>=</span>
<a name="line-198"></a> <span class='hs-varid'>foldDecompressStream</span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-conid'>Chunk</span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-conid'>Empty</span>
<a name="line-199"></a> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-sel'>_code</span> <span class='hs-varid'>msg</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>error</span> <span class='hs-layout'>(</span><span class='hs-str'>"Codec.Compression.Zlib: "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>msg</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-200"></a>
<a name="line-201"></a><span class='hs-comment'>--TODO: throw DecompressError as an Exception class type and document that it</span>
<a name="line-202"></a><span class='hs-comment'>-- does this.</span>
<a name="line-203"></a>
<a name="line-204"></a><a name="compress"></a><span class='hs-comment'>-- | Compress a data stream.</span>
<a name="line-205"></a><span class='hs-comment'>--</span>
<a name="line-206"></a><span class='hs-comment'>-- There are no expected error conditions. All input data streams are valid. It</span>
<a name="line-207"></a><span class='hs-comment'>-- is possible for unexpected errors to occur, such as running out of memory,</span>
<a name="line-208"></a><span class='hs-comment'>-- or finding the wrong version of the zlib C library, these are thrown as</span>
<a name="line-209"></a><span class='hs-comment'>-- exceptions.</span>
<a name="line-210"></a><span class='hs-comment'>--</span>
<a name="line-211"></a><span class='hs-definition'>compress</span>
<a name="line-212"></a> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Format</span>
<a name="line-213"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>CompressParams</span>
<a name="line-214"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span>
<a name="line-215"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span>
<a name="line-216"></a><span class='hs-definition'>compress</span> <span class='hs-varid'>format</span>
<a name="line-217"></a> <span class='hs-layout'>(</span><span class='hs-conid'>CompressParams</span> <span class='hs-varid'>compLevel</span> <span class='hs-varid'>method</span> <span class='hs-varid'>bits</span> <span class='hs-varid'>memLevel</span> <span class='hs-varid'>strategy</span> <span class='hs-varid'>initChunkSize</span><span class='hs-layout'>)</span>
<a name="line-218"></a> <span class='hs-varid'>input</span> <span class='hs-keyglyph'>=</span>
<a name="line-219"></a> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-varid'>fromChunks</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>run</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-220"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>deflateInit</span> <span class='hs-varid'>format</span> <span class='hs-varid'>compLevel</span> <span class='hs-varid'>method</span> <span class='hs-varid'>bits</span> <span class='hs-varid'>memLevel</span> <span class='hs-varid'>strategy</span>
<a name="line-221"></a> <span class='hs-keyword'>case</span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-varid'>toChunks</span> <span class='hs-varid'>input</span> <span class='hs-keyword'>of</span>
<a name="line-222"></a> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fillBuffers</span> <span class='hs-num'>20</span> <span class='hs-conid'>[]</span> <span class='hs-comment'>--gzip header is 20 bytes, others even smaller</span>
<a name="line-223"></a> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>PS</span> <span class='hs-varid'>inFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span> <span class='hs-conop'>:</span> <span class='hs-varid'>chunks</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-224"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>pushInputBuffer</span> <span class='hs-varid'>inFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span>
<a name="line-225"></a> <span class='hs-varid'>fillBuffers</span> <span class='hs-varid'>initChunkSize</span> <span class='hs-varid'>chunks</span>
<a name="line-226"></a>
<a name="line-227"></a> <span class='hs-keyword'>where</span>
<a name="line-228"></a> <span class='hs-comment'>-- we flick between two states:</span>
<a name="line-229"></a> <span class='hs-comment'>-- * where one or other buffer is empty</span>
<a name="line-230"></a> <span class='hs-comment'>-- - in which case we refill one or both</span>
<a name="line-231"></a> <span class='hs-comment'>-- * where both buffers are non-empty</span>
<a name="line-232"></a> <span class='hs-comment'>-- - in which case we compress until a buffer is empty</span>
<a name="line-233"></a>
<a name="line-234"></a> <span class='hs-varid'>fillBuffers</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span>
<a name="line-235"></a> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-keyglyph'>]</span>
<a name="line-236"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Stream</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-keyglyph'>]</span>
<a name="line-237"></a> <span class='hs-varid'>fillBuffers</span> <span class='hs-varid'>outChunkSize</span> <span class='hs-varid'>inChunks</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-238"></a><span class='hs-cpp'>#ifdef DEBUG</span>
<a name="line-239"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>consistencyCheck</span>
<a name="line-240"></a><span class='hs-cpp'>#endif</span>
<a name="line-241"></a>
<a name="line-242"></a> <span class='hs-comment'>-- in this state there are two possabilities:</span>
<a name="line-243"></a> <span class='hs-comment'>-- * no outbut buffer space is available</span>
<a name="line-244"></a> <span class='hs-comment'>-- - in which case we must make more available</span>
<a name="line-245"></a> <span class='hs-comment'>-- * no input buffer is available</span>
<a name="line-246"></a> <span class='hs-comment'>-- - in which case we must supply more</span>
<a name="line-247"></a> <span class='hs-varid'>inputBufferEmpty</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>inputBufferEmpty</span>
<a name="line-248"></a> <span class='hs-varid'>outputBufferFull</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>outputBufferFull</span>
<a name="line-249"></a>
<a name="line-250"></a> <span class='hs-varid'>assert</span> <span class='hs-layout'>(</span><span class='hs-varid'>inputBufferEmpty</span> <span class='hs-varop'>||</span> <span class='hs-varid'>outputBufferFull</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-251"></a>
<a name="line-252"></a> <span class='hs-varid'>when</span> <span class='hs-varid'>outputBufferFull</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-253"></a> <span class='hs-varid'>outFPtr</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>unsafeLiftIO</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>mallocByteString</span> <span class='hs-varid'>outChunkSize</span><span class='hs-layout'>)</span>
<a name="line-254"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>pushOutputBuffer</span> <span class='hs-varid'>outFPtr</span> <span class='hs-num'>0</span> <span class='hs-varid'>outChunkSize</span>
<a name="line-255"></a>
<a name="line-256"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>inputBufferEmpty</span>
<a name="line-257"></a> <span class='hs-keyword'>then</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>inChunks</span> <span class='hs-keyword'>of</span>
<a name="line-258"></a> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>drainBuffers</span> <span class='hs-conid'>[]</span>
<a name="line-259"></a> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>PS</span> <span class='hs-varid'>inFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span> <span class='hs-conop'>:</span> <span class='hs-varid'>inChunks'</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-260"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>pushInputBuffer</span> <span class='hs-varid'>inFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span>
<a name="line-261"></a> <span class='hs-varid'>drainBuffers</span> <span class='hs-varid'>inChunks'</span>
<a name="line-262"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>drainBuffers</span> <span class='hs-varid'>inChunks</span>
<a name="line-263"></a>
<a name="line-264"></a>
<a name="line-265"></a> <span class='hs-varid'>drainBuffers</span> <span class='hs-keyglyph'>::</span>
<a name="line-266"></a> <span class='hs-keyglyph'>[</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-keyglyph'>]</span>
<a name="line-267"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Stream</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-keyglyph'>]</span>
<a name="line-268"></a> <span class='hs-varid'>drainBuffers</span> <span class='hs-varid'>inChunks</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-269"></a>
<a name="line-270"></a> <span class='hs-varid'>inputBufferEmpty'</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>inputBufferEmpty</span>
<a name="line-271"></a> <span class='hs-varid'>outputBufferFull'</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>outputBufferFull</span>
<a name="line-272"></a> <span class='hs-varid'>assert</span><span class='hs-layout'>(</span><span class='hs-varid'>not</span> <span class='hs-varid'>outputBufferFull'</span>
<a name="line-273"></a> <span class='hs-varop'>&&</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span> <span class='hs-varid'>inChunks</span> <span class='hs-varop'>||</span> <span class='hs-varid'>not</span> <span class='hs-varid'>inputBufferEmpty'</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-274"></a> <span class='hs-comment'>-- this invariant guarantees we can always make forward progress</span>
<a name="line-275"></a> <span class='hs-comment'>-- and that therefore a BufferError is impossible</span>
<a name="line-276"></a>
<a name="line-277"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>flush</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>null</span> <span class='hs-varid'>inChunks</span> <span class='hs-keyword'>then</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Finish</span> <span class='hs-keyword'>else</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>NoFlush</span>
<a name="line-278"></a> <span class='hs-varid'>status</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>deflate</span> <span class='hs-varid'>flush</span>
<a name="line-279"></a>
<a name="line-280"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>status</span> <span class='hs-keyword'>of</span>
<a name="line-281"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Ok</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-282"></a> <span class='hs-varid'>outputBufferFull</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>outputBufferFull</span>
<a name="line-283"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>outputBufferFull</span>
<a name="line-284"></a> <span class='hs-keyword'>then</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>(</span><span class='hs-varid'>outFPtr</span><span class='hs-layout'>,</span> <span class='hs-varid'>offset</span><span class='hs-layout'>,</span> <span class='hs-varid'>length</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>popOutputBuffer</span>
<a name="line-285"></a> <span class='hs-varid'>outChunks</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>unsafeInterleave</span>
<a name="line-286"></a> <span class='hs-layout'>(</span><span class='hs-varid'>fillBuffers</span> <span class='hs-varid'>defaultCompressBufferSize</span> <span class='hs-varid'>inChunks</span><span class='hs-layout'>)</span>
<a name="line-287"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>PS</span> <span class='hs-varid'>outFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span> <span class='hs-conop'>:</span> <span class='hs-varid'>outChunks</span><span class='hs-layout'>)</span>
<a name="line-288"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>fillBuffers</span> <span class='hs-varid'>defaultCompressBufferSize</span> <span class='hs-varid'>inChunks</span>
<a name="line-289"></a>
<a name="line-290"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>StreamEnd</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-291"></a> <span class='hs-varid'>inputBufferEmpty</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>inputBufferEmpty</span>
<a name="line-292"></a> <span class='hs-varid'>assert</span> <span class='hs-varid'>inputBufferEmpty</span> <span class='hs-varop'>$</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-293"></a> <span class='hs-varid'>outputBufferBytesAvailable</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>outputBufferBytesAvailable</span>
<a name="line-294"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>outputBufferBytesAvailable</span> <span class='hs-varop'>></span> <span class='hs-num'>0</span>
<a name="line-295"></a> <span class='hs-keyword'>then</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>(</span><span class='hs-varid'>outFPtr</span><span class='hs-layout'>,</span> <span class='hs-varid'>offset</span><span class='hs-layout'>,</span> <span class='hs-varid'>length</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>popOutputBuffer</span>
<a name="line-296"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>finalise</span>
<a name="line-297"></a> <span class='hs-varid'>return</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>PS</span> <span class='hs-varid'>outFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span><span class='hs-keyglyph'>]</span>
<a name="line-298"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>do</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>finalise</span>
<a name="line-299"></a> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-300"></a>
<a name="line-301"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Error</span> <span class='hs-varid'>code</span> <span class='hs-varid'>msg</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>code</span> <span class='hs-keyword'>of</span>
<a name="line-302"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>BufferError</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fail</span> <span class='hs-str'>"BufferError should be impossible!"</span>
<a name="line-303"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>NeedDict</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fail</span> <span class='hs-str'>"NeedDict is impossible!"</span>
<a name="line-304"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fail</span> <span class='hs-varid'>msg</span>
<a name="line-305"></a>
<a name="line-306"></a>
<a name="line-307"></a><a name="decompress"></a><span class='hs-comment'>-- | Decompress a data stream.</span>
<a name="line-308"></a><span class='hs-comment'>--</span>
<a name="line-309"></a><span class='hs-comment'>-- It will throw an exception if any error is encountered in the input data. If</span>
<a name="line-310"></a><span class='hs-comment'>-- you need more control over error handling then use 'decompressWithErrors'.</span>
<a name="line-311"></a><span class='hs-comment'>--</span>
<a name="line-312"></a><span class='hs-definition'>decompress</span>
<a name="line-313"></a> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Format</span>
<a name="line-314"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>DecompressParams</span>
<a name="line-315"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span>
<a name="line-316"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span>
<a name="line-317"></a><span class='hs-definition'>decompress</span> <span class='hs-varid'>format</span> <span class='hs-varid'>params</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fromDecompressStream</span>
<a name="line-318"></a> <span class='hs-varop'>.</span> <span class='hs-varid'>decompressWithErrors</span> <span class='hs-varid'>format</span> <span class='hs-varid'>params</span>
<a name="line-319"></a>
<a name="line-320"></a><a name="decompressWithErrors"></a><span class='hs-comment'>-- | Like 'decompress' but returns a 'DecompressStream' data structure that</span>
<a name="line-321"></a><span class='hs-comment'>-- contains an explicit representation of the error conditions that one may</span>
<a name="line-322"></a><span class='hs-comment'>-- encounter when decompressing.</span>
<a name="line-323"></a><span class='hs-comment'>--</span>
<a name="line-324"></a><span class='hs-comment'>-- Note that in addition to errors in the input data, it is possible for other</span>
<a name="line-325"></a><span class='hs-comment'>-- unexpected errors to occur, such as out of memory, or finding the wrong</span>
<a name="line-326"></a><span class='hs-comment'>-- version of the zlib C library, these are still thrown as exceptions (because</span>
<a name="line-327"></a><span class='hs-comment'>-- representing them as data would make this function impure).</span>
<a name="line-328"></a><span class='hs-comment'>--</span>
<a name="line-329"></a><span class='hs-definition'>decompressWithErrors</span>
<a name="line-330"></a> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Format</span>
<a name="line-331"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>DecompressParams</span>
<a name="line-332"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span>
<a name="line-333"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>DecompressStream</span>
<a name="line-334"></a><span class='hs-definition'>decompressWithErrors</span> <span class='hs-varid'>format</span> <span class='hs-layout'>(</span><span class='hs-conid'>DecompressParams</span> <span class='hs-varid'>bits</span> <span class='hs-varid'>initChunkSize</span><span class='hs-layout'>)</span> <span class='hs-varid'>input</span> <span class='hs-keyglyph'>=</span>
<a name="line-335"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>run</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-336"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>inflateInit</span> <span class='hs-varid'>format</span> <span class='hs-varid'>bits</span>
<a name="line-337"></a> <span class='hs-keyword'>case</span> <span class='hs-conid'>L</span><span class='hs-varop'>.</span><span class='hs-varid'>toChunks</span> <span class='hs-varid'>input</span> <span class='hs-keyword'>of</span>
<a name="line-338"></a> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fillBuffers</span> <span class='hs-num'>4</span> <span class='hs-conid'>[]</span> <span class='hs-comment'>--always an error anyway</span>
<a name="line-339"></a> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>PS</span> <span class='hs-varid'>inFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span> <span class='hs-conop'>:</span> <span class='hs-varid'>chunks</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-340"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>pushInputBuffer</span> <span class='hs-varid'>inFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span>
<a name="line-341"></a> <span class='hs-varid'>fillBuffers</span> <span class='hs-varid'>initChunkSize</span> <span class='hs-varid'>chunks</span>
<a name="line-342"></a>
<a name="line-343"></a> <span class='hs-keyword'>where</span>
<a name="line-344"></a> <span class='hs-comment'>-- we flick between two states:</span>
<a name="line-345"></a> <span class='hs-comment'>-- * where one or other buffer is empty</span>
<a name="line-346"></a> <span class='hs-comment'>-- - in which case we refill one or both</span>
<a name="line-347"></a> <span class='hs-comment'>-- * where both buffers are non-empty</span>
<a name="line-348"></a> <span class='hs-comment'>-- - in which case we compress until a buffer is empty</span>
<a name="line-349"></a>
<a name="line-350"></a> <span class='hs-varid'>fillBuffers</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span>
<a name="line-351"></a> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-keyglyph'>]</span>
<a name="line-352"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Stream</span> <span class='hs-conid'>DecompressStream</span>
<a name="line-353"></a> <span class='hs-varid'>fillBuffers</span> <span class='hs-varid'>outChunkSize</span> <span class='hs-varid'>inChunks</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-354"></a><span class='hs-cpp'>#ifdef DEBUG</span>
<a name="line-355"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>consistencyCheck</span>
<a name="line-356"></a><span class='hs-cpp'>#endif</span>
<a name="line-357"></a>
<a name="line-358"></a> <span class='hs-comment'>-- in this state there are two possabilities:</span>
<a name="line-359"></a> <span class='hs-comment'>-- * no outbut buffer space is available</span>
<a name="line-360"></a> <span class='hs-comment'>-- - in which case we must make more available</span>
<a name="line-361"></a> <span class='hs-comment'>-- * no input buffer is available</span>
<a name="line-362"></a> <span class='hs-comment'>-- - in which case we must supply more</span>
<a name="line-363"></a> <span class='hs-varid'>inputBufferEmpty</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>inputBufferEmpty</span>
<a name="line-364"></a> <span class='hs-varid'>outputBufferFull</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>outputBufferFull</span>
<a name="line-365"></a>
<a name="line-366"></a> <span class='hs-varid'>assert</span> <span class='hs-layout'>(</span><span class='hs-varid'>inputBufferEmpty</span> <span class='hs-varop'>||</span> <span class='hs-varid'>outputBufferFull</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-367"></a>
<a name="line-368"></a> <span class='hs-varid'>when</span> <span class='hs-varid'>outputBufferFull</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-369"></a> <span class='hs-varid'>outFPtr</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>unsafeLiftIO</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>mallocByteString</span> <span class='hs-varid'>outChunkSize</span><span class='hs-layout'>)</span>
<a name="line-370"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>pushOutputBuffer</span> <span class='hs-varid'>outFPtr</span> <span class='hs-num'>0</span> <span class='hs-varid'>outChunkSize</span>
<a name="line-371"></a>
<a name="line-372"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>inputBufferEmpty</span>
<a name="line-373"></a> <span class='hs-keyword'>then</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>inChunks</span> <span class='hs-keyword'>of</span>
<a name="line-374"></a> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>drainBuffers</span> <span class='hs-conid'>[]</span>
<a name="line-375"></a> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>PS</span> <span class='hs-varid'>inFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span> <span class='hs-conop'>:</span> <span class='hs-varid'>inChunks'</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-376"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>pushInputBuffer</span> <span class='hs-varid'>inFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span>
<a name="line-377"></a> <span class='hs-varid'>drainBuffers</span> <span class='hs-varid'>inChunks'</span>
<a name="line-378"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>drainBuffers</span> <span class='hs-varid'>inChunks</span>
<a name="line-379"></a>
<a name="line-380"></a>
<a name="line-381"></a> <span class='hs-varid'>drainBuffers</span> <span class='hs-keyglyph'>::</span>
<a name="line-382"></a> <span class='hs-keyglyph'>[</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-keyglyph'>]</span>
<a name="line-383"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Stream</span> <span class='hs-conid'>DecompressStream</span>
<a name="line-384"></a> <span class='hs-varid'>drainBuffers</span> <span class='hs-varid'>inChunks</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-385"></a>
<a name="line-386"></a> <span class='hs-varid'>inputBufferEmpty'</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>inputBufferEmpty</span>
<a name="line-387"></a> <span class='hs-varid'>outputBufferFull'</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>outputBufferFull</span>
<a name="line-388"></a> <span class='hs-varid'>assert</span><span class='hs-layout'>(</span><span class='hs-varid'>not</span> <span class='hs-varid'>outputBufferFull'</span>
<a name="line-389"></a> <span class='hs-varop'>&&</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span> <span class='hs-varid'>inChunks</span> <span class='hs-varop'>||</span> <span class='hs-varid'>not</span> <span class='hs-varid'>inputBufferEmpty'</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-390"></a> <span class='hs-comment'>-- this invariant guarantees we can always make forward progress or at</span>
<a name="line-391"></a> <span class='hs-comment'>-- least if a BufferError does occur that it must be due to a premature EOF</span>
<a name="line-392"></a>
<a name="line-393"></a> <span class='hs-varid'>status</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>inflate</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>NoFlush</span>
<a name="line-394"></a>
<a name="line-395"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>status</span> <span class='hs-keyword'>of</span>
<a name="line-396"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Ok</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-397"></a> <span class='hs-varid'>outputBufferFull</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>outputBufferFull</span>
<a name="line-398"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>outputBufferFull</span>
<a name="line-399"></a> <span class='hs-keyword'>then</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>(</span><span class='hs-varid'>outFPtr</span><span class='hs-layout'>,</span> <span class='hs-varid'>offset</span><span class='hs-layout'>,</span> <span class='hs-varid'>length</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>popOutputBuffer</span>
<a name="line-400"></a> <span class='hs-varid'>outChunks</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>unsafeInterleave</span>
<a name="line-401"></a> <span class='hs-layout'>(</span><span class='hs-varid'>fillBuffers</span> <span class='hs-varid'>defaultDecompressBufferSize</span> <span class='hs-varid'>inChunks</span><span class='hs-layout'>)</span>
<a name="line-402"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>StreamChunk</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>PS</span> <span class='hs-varid'>outFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span><span class='hs-layout'>)</span> <span class='hs-varid'>outChunks</span>
<a name="line-403"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>fillBuffers</span> <span class='hs-varid'>defaultDecompressBufferSize</span> <span class='hs-varid'>inChunks</span>
<a name="line-404"></a>
<a name="line-405"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>StreamEnd</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>finish</span> <span class='hs-conid'>StreamEnd</span>
<a name="line-406"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>Error</span> <span class='hs-varid'>code</span> <span class='hs-varid'>msg</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>code</span> <span class='hs-keyword'>of</span>
<a name="line-407"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>BufferError</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>finish</span> <span class='hs-layout'>(</span><span class='hs-conid'>StreamError</span> <span class='hs-conid'>TruncatedInput</span> <span class='hs-varid'>msg'</span><span class='hs-layout'>)</span>
<a name="line-408"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>msg'</span> <span class='hs-keyglyph'>=</span> <span class='hs-str'>"premature end of compressed stream"</span>
<a name="line-409"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>NeedDict</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>finish</span> <span class='hs-layout'>(</span><span class='hs-conid'>StreamError</span> <span class='hs-conid'>DictionaryRequired</span> <span class='hs-varid'>msg</span><span class='hs-layout'>)</span>
<a name="line-410"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-conid'>DataError</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>finish</span> <span class='hs-layout'>(</span><span class='hs-conid'>StreamError</span> <span class='hs-conid'>DataError</span> <span class='hs-varid'>msg</span><span class='hs-layout'>)</span>
<a name="line-411"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fail</span> <span class='hs-varid'>msg</span>
<a name="line-412"></a>
<a name="line-413"></a> <span class='hs-comment'>-- Note even if we end with an error we still try to flush the last chunk if</span>
<a name="line-414"></a> <span class='hs-comment'>-- there is one. The user just has to decide what they want to trust.</span>
<a name="line-415"></a> <span class='hs-varid'>finish</span> <span class='hs-varid'>end</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-416"></a> <span class='hs-comment'>-- Note that there may be input bytes still available if the stream</span>
<a name="line-417"></a> <span class='hs-comment'>-- is embeded in some other data stream. Here we just silently discard</span>
<a name="line-418"></a> <span class='hs-comment'>-- any trailing data.</span>
<a name="line-419"></a> <span class='hs-varid'>outputBufferBytesAvailable</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>outputBufferBytesAvailable</span>
<a name="line-420"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>outputBufferBytesAvailable</span> <span class='hs-varop'>></span> <span class='hs-num'>0</span>
<a name="line-421"></a> <span class='hs-keyword'>then</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>(</span><span class='hs-varid'>outFPtr</span><span class='hs-layout'>,</span> <span class='hs-varid'>offset</span><span class='hs-layout'>,</span> <span class='hs-varid'>length</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>popOutputBuffer</span>
<a name="line-422"></a> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>finalise</span>
<a name="line-423"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>StreamChunk</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>PS</span> <span class='hs-varid'>outFPtr</span> <span class='hs-varid'>offset</span> <span class='hs-varid'>length</span><span class='hs-layout'>)</span> <span class='hs-varid'>end</span><span class='hs-layout'>)</span>
<a name="line-424"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>do</span> <span class='hs-conid'>Stream</span><span class='hs-varop'>.</span><span class='hs-varid'>finalise</span>
<a name="line-425"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>end</span>
</pre></body>
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