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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE CPP, ForeignFunctionInterface #-}</span>
<a name="line-2"></a><span class='hs-comment'>-- We cannot actually specify all the language pragmas, see ghc ticket #</span>
<a name="line-3"></a><span class='hs-comment'>-- If we could, these are what they would be:</span>
<a name="line-4"></a><span class='hs-comment'>{- LANGUAGE DeriveDataTypeable -}</span>
<a name="line-5"></a><span class='hs-comment'>{-# OPTIONS_HADDOCK hide #-}</span>
<a name="line-6"></a>
<a name="line-7"></a><span class='hs-comment'>-- |</span>
<a name="line-8"></a><span class='hs-comment'>-- Module : Data.ByteString.Lazy.Internal</span>
<a name="line-9"></a><span class='hs-comment'>-- License : BSD-style</span>
<a name="line-10"></a><span class='hs-comment'>-- Maintainer : dons@galois.com, duncan@haskell.org</span>
<a name="line-11"></a><span class='hs-comment'>-- Stability : experimental</span>
<a name="line-12"></a><span class='hs-comment'>-- Portability : portable</span>
<a name="line-13"></a><span class='hs-comment'>-- </span>
<a name="line-14"></a><span class='hs-comment'>-- A module containing semi-public 'ByteString' internals. This exposes</span>
<a name="line-15"></a><span class='hs-comment'>-- the 'ByteString' representation and low level construction functions.</span>
<a name="line-16"></a><span class='hs-comment'>-- Modules which extend the 'ByteString' system will need to use this module</span>
<a name="line-17"></a><span class='hs-comment'>-- while ideally most users will be able to make do with the public interface</span>
<a name="line-18"></a><span class='hs-comment'>-- modules.</span>
<a name="line-19"></a><span class='hs-comment'>--</span>
<a name="line-20"></a><span class='hs-keyword'>module</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-layout'>(</span>
<a name="line-21"></a>
<a name="line-22"></a> <span class='hs-comment'>-- * The lazy @ByteString@ type and representation</span>
<a name="line-23"></a> <span class='hs-conid'>ByteString</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-comment'>-- instances: Eq, Ord, Show, Read, Data, Typeable</span>
<a name="line-24"></a> <span class='hs-varid'>chunk</span><span class='hs-layout'>,</span>
<a name="line-25"></a> <span class='hs-varid'>foldrChunks</span><span class='hs-layout'>,</span>
<a name="line-26"></a> <span class='hs-varid'>foldlChunks</span><span class='hs-layout'>,</span>
<a name="line-27"></a>
<a name="line-28"></a> <span class='hs-comment'>-- * Data type invariant and abstraction function</span>
<a name="line-29"></a> <span class='hs-varid'>invariant</span><span class='hs-layout'>,</span>
<a name="line-30"></a> <span class='hs-varid'>checkInvariant</span><span class='hs-layout'>,</span>
<a name="line-31"></a>
<a name="line-32"></a> <span class='hs-comment'>-- * Chunk allocation sizes</span>
<a name="line-33"></a> <span class='hs-varid'>defaultChunkSize</span><span class='hs-layout'>,</span>
<a name="line-34"></a> <span class='hs-varid'>smallChunkSize</span><span class='hs-layout'>,</span>
<a name="line-35"></a> <span class='hs-varid'>chunkOverhead</span>
<a name="line-36"></a>
<a name="line-37"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-38"></a>
<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'>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-40"></a>
<a name="line-41"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Storable</span> <span class='hs-layout'>(</span><span class='hs-conid'>Storable</span><span class='hs-layout'>(</span><span class='hs-varid'>sizeOf</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-42"></a>
<a name="line-43"></a><span class='hs-cpp'>#if defined(__GLASGOW_HASKELL__)</span>
<a name="line-44"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Typeable</span> <span class='hs-layout'>(</span><span class='hs-conid'>Typeable</span><span class='hs-layout'>)</span>
<a name="line-45"></a><span class='hs-cpp'>#if __GLASGOW_HASKELL__ >= 610</span>
<a name="line-46"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Data</span> <span class='hs-layout'>(</span><span class='hs-conid'>Data</span><span class='hs-layout'>)</span>
<a name="line-47"></a><span class='hs-cpp'>#else</span>
<a name="line-48"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Generics</span> <span class='hs-layout'>(</span><span class='hs-conid'>Data</span><span class='hs-layout'>)</span>
<a name="line-49"></a><span class='hs-cpp'>#endif</span>
<a name="line-50"></a><span class='hs-cpp'>#endif</span>
<a name="line-51"></a>
<a name="line-52"></a><a name="ByteString"></a><span class='hs-comment'>-- | A space-efficient representation of a Word8 vector, supporting many</span>
<a name="line-53"></a><a name="ByteString"></a><span class='hs-comment'>-- efficient operations. A 'ByteString' contains 8-bit characters only.</span>
<a name="line-54"></a><a name="ByteString"></a><span class='hs-comment'>--</span>
<a name="line-55"></a><a name="ByteString"></a><span class='hs-comment'>-- Instances of Eq, Ord, Read, Show, Data, Typeable</span>
<a name="line-56"></a><a name="ByteString"></a><span class='hs-comment'>--</span>
<a name="line-57"></a><a name="ByteString"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Chunk</span> <span class='hs-comment'>{-# UNPACK #-}</span> <span class='hs-varop'>!</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span> <span class='hs-conid'>ByteString</span>
<a name="line-58"></a> <span class='hs-keyword'>deriving</span> <span class='hs-layout'>(</span><span class='hs-conid'>Show</span><span class='hs-layout'>,</span> <span class='hs-conid'>Read</span>
<a name="line-59"></a><span class='hs-cpp'>#if defined(__GLASGOW_HASKELL__)</span>
<a name="line-60"></a> <span class='hs-layout'>,</span><span class='hs-conid'>Data</span><span class='hs-layout'>,</span> <span class='hs-conid'>Typeable</span>
<a name="line-61"></a><span class='hs-cpp'>#endif</span>
<a name="line-62"></a> <span class='hs-layout'>)</span>
<a name="line-63"></a>
<a name="line-64"></a><span class='hs-comment'>------------------------------------------------------------------------</span>
<a name="line-65"></a>
<a name="line-66"></a><a name="invariant"></a><span class='hs-comment'>-- | The data type invariant:</span>
<a name="line-67"></a><span class='hs-comment'>-- Every ByteString is either 'Empty' or consists of non-null 'S.ByteString's.</span>
<a name="line-68"></a><span class='hs-comment'>-- All functions must preserve this, and the QC properties must check this.</span>
<a name="line-69"></a><span class='hs-comment'>--</span>
<a name="line-70"></a><span class='hs-definition'>invariant</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-71"></a><span class='hs-definition'>invariant</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-72"></a><span class='hs-definition'>invariant</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunk</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-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>len</span><span class='hs-layout'>)</span> <span class='hs-varid'>cs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>len</span> <span class='hs-varop'>></span> <span class='hs-num'>0</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>invariant</span> <span class='hs-varid'>cs</span>
<a name="line-73"></a>
<a name="line-74"></a><a name="checkInvariant"></a><span class='hs-comment'>-- | In a form that checks the invariant lazily.</span>
<a name="line-75"></a><span class='hs-definition'>checkInvariant</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteString</span>
<a name="line-76"></a><span class='hs-definition'>checkInvariant</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Empty</span>
<a name="line-77"></a><span class='hs-definition'>checkInvariant</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunk</span> <span class='hs-varid'>c</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'>PS</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>len</span><span class='hs-layout'>)</span> <span class='hs-varid'>cs</span><span class='hs-layout'>)</span>
<a name="line-78"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>len</span> <span class='hs-varop'>></span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Chunk</span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-varid'>checkInvariant</span> <span class='hs-varid'>cs</span><span class='hs-layout'>)</span>
<a name="line-79"></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-varop'>$</span> <span class='hs-str'>"Data.ByteString.Lazy: invariant violation:"</span>
<a name="line-80"></a> <span class='hs-varop'>++</span> <span class='hs-varid'>show</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunk</span> <span class='hs-varid'>c</span> <span class='hs-varid'>cs</span><span class='hs-layout'>)</span>
<a name="line-81"></a>
<a name="line-82"></a><span class='hs-comment'>------------------------------------------------------------------------</span>
<a name="line-83"></a>
<a name="line-84"></a><a name="chunk"></a><span class='hs-comment'>-- | Smart constructor for 'Chunk'. Guarantees the data type invariant.</span>
<a name="line-85"></a><span class='hs-definition'>chunk</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> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteString</span>
<a name="line-86"></a><span class='hs-definition'>chunk</span> <span class='hs-varid'>c</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'>PS</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>len</span><span class='hs-layout'>)</span> <span class='hs-varid'>cs</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>len</span> <span class='hs-varop'>==</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>cs</span>
<a name="line-87"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Chunk</span> <span class='hs-varid'>c</span> <span class='hs-varid'>cs</span>
<a name="line-88"></a><span class='hs-comment'>{-# INLINE chunk #-}</span>
<a name="line-89"></a>
<a name="line-90"></a><a name="foldrChunks"></a><span class='hs-comment'>-- | Consume the chunks of a lazy ByteString with a natural right fold.</span>
<a name="line-91"></a><span class='hs-definition'>foldrChunks</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> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span>
<a name="line-92"></a><span class='hs-definition'>foldrChunks</span> <span class='hs-varid'>f</span> <span class='hs-varid'>z</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span>
<a name="line-93"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>go</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>z</span>
<a name="line-94"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunk</span> <span class='hs-varid'>c</span> <span class='hs-varid'>cs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>cs</span><span class='hs-layout'>)</span>
<a name="line-95"></a><span class='hs-comment'>{-# INLINE foldrChunks #-}</span>
<a name="line-96"></a>
<a name="line-97"></a><a name="foldlChunks"></a><span class='hs-comment'>-- | Consume the chunks of a lazy ByteString with a strict, tail-recursive,</span>
<a name="line-98"></a><span class='hs-comment'>-- accumulating left fold.</span>
<a name="line-99"></a><span class='hs-definition'>foldlChunks</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</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> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span>
<a name="line-100"></a><span class='hs-definition'>foldlChunks</span> <span class='hs-varid'>f</span> <span class='hs-varid'>z</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>z</span>
<a name="line-101"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>go</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>a</span> <span class='hs-varop'>`seq`</span> <span class='hs-conid'>False</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>undefined</span>
<a name="line-102"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>a</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>a</span>
<a name="line-103"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>a</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunk</span> <span class='hs-varid'>c</span> <span class='hs-varid'>cs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>a</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-varid'>cs</span>
<a name="line-104"></a><span class='hs-comment'>{-# INLINE foldlChunks #-}</span>
<a name="line-105"></a>
<a name="line-106"></a><span class='hs-comment'>------------------------------------------------------------------------</span>
<a name="line-107"></a>
<a name="line-108"></a><span class='hs-comment'>-- The representation uses lists of packed chunks. When we have to convert from</span>
<a name="line-109"></a><span class='hs-comment'>-- a lazy list to the chunked representation, then by default we use this</span>
<a name="line-110"></a><span class='hs-comment'>-- chunk size. Some functions give you more control over the chunk size.</span>
<a name="line-111"></a><span class='hs-comment'>--</span>
<a name="line-112"></a><span class='hs-comment'>-- Measurements here:</span>
<a name="line-113"></a><span class='hs-comment'>-- <a href="http://www.cse.unsw.edu.au/~dons/tmp/chunksize_v_cache.png">http://www.cse.unsw.edu.au/~dons/tmp/chunksize_v_cache.png</a></span>
<a name="line-114"></a><span class='hs-comment'>--</span>
<a name="line-115"></a><span class='hs-comment'>-- indicate that a value around 0.5 to 1 x your L2 cache is best.</span>
<a name="line-116"></a><span class='hs-comment'>-- The following value assumes people have something greater than 128k,</span>
<a name="line-117"></a><span class='hs-comment'>-- and need to share the cache with other programs.</span>
<a name="line-118"></a>
<a name="line-119"></a><a name="defaultChunkSize"></a><span class='hs-comment'>-- | Currently set to 32k, less the memory management overhead</span>
<a name="line-120"></a><span class='hs-definition'>defaultChunkSize</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span>
<a name="line-121"></a><span class='hs-definition'>defaultChunkSize</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>32</span> <span class='hs-varop'>*</span> <span class='hs-varid'>k</span> <span class='hs-comment'>-</span> <span class='hs-varid'>chunkOverhead</span>
<a name="line-122"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>1024</span>
<a name="line-123"></a>
<a name="line-124"></a><a name="smallChunkSize"></a><span class='hs-comment'>-- | Currently set to 4k, less the memory management overhead</span>
<a name="line-125"></a><span class='hs-definition'>smallChunkSize</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span>
<a name="line-126"></a><span class='hs-definition'>smallChunkSize</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>4</span> <span class='hs-varop'>*</span> <span class='hs-varid'>k</span> <span class='hs-comment'>-</span> <span class='hs-varid'>chunkOverhead</span>
<a name="line-127"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>1024</span>
<a name="line-128"></a>
<a name="line-129"></a><a name="chunkOverhead"></a><span class='hs-comment'>-- | The memory management overhead. Currently this is tuned for GHC only.</span>
<a name="line-130"></a><span class='hs-definition'>chunkOverhead</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span>
<a name="line-131"></a><span class='hs-definition'>chunkOverhead</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>2</span> <span class='hs-varop'>*</span> <span class='hs-varid'>sizeOf</span> <span class='hs-layout'>(</span><span class='hs-varid'>undefined</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span><span class='hs-layout'>)</span>
</pre></body>
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