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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE BangPatterns, CPP #-}</span>
<a name="line-2"></a><span class='hs-comment'>-- |</span>
<a name="line-3"></a><span class='hs-comment'>-- Module : Data.Text.Foreign</span>
<a name="line-4"></a><span class='hs-comment'>-- Copyright : (c) 2009, 2010 Bryan O'Sullivan</span>
<a name="line-5"></a><span class='hs-comment'>--</span>
<a name="line-6"></a><span class='hs-comment'>-- License : BSD-style</span>
<a name="line-7"></a><span class='hs-comment'>-- Maintainer : bos@serpentine.com, rtomharper@googlemail.com,</span>
<a name="line-8"></a><span class='hs-comment'>-- duncan@haskell.org</span>
<a name="line-9"></a><span class='hs-comment'>-- Stability : experimental</span>
<a name="line-10"></a><span class='hs-comment'>-- Portability : GHC</span>
<a name="line-11"></a><span class='hs-comment'>--</span>
<a name="line-12"></a><span class='hs-comment'>-- Support for using 'Text' data with native code via the Haskell</span>
<a name="line-13"></a><span class='hs-comment'>-- foreign function interface.</span>
<a name="line-14"></a>
<a name="line-15"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Text</span><span class='hs-varop'>.</span><span class='hs-conid'>Foreign</span>
<a name="line-16"></a> <span class='hs-layout'>(</span>
<a name="line-17"></a> <span class='hs-comment'>-- * Interoperability with native code</span>
<a name="line-18"></a> <span class='hs-comment'>-- $interop</span>
<a name="line-19"></a>
<a name="line-20"></a> <span class='hs-comment'>-- * Safe conversion functions</span>
<a name="line-21"></a> <span class='hs-varid'>fromPtr</span>
<a name="line-22"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>useAsPtr</span>
<a name="line-23"></a> <span class='hs-comment'>-- * Unsafe conversion code</span>
<a name="line-24"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>lengthWord16</span>
<a name="line-25"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>unsafeCopyToPtr</span>
<a name="line-26"></a> <span class='hs-comment'>-- * Low-level manipulation</span>
<a name="line-27"></a> <span class='hs-comment'>-- $lowlevel</span>
<a name="line-28"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>dropWord16</span>
<a name="line-29"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>takeWord16</span>
<a name="line-30"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-31"></a>
<a name="line-32"></a><span class='hs-cpp'>#if defined(ASSERTS)</span>
<a name="line-33"></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-34"></a><span class='hs-cpp'>#endif</span>
<a name="line-35"></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-varop'>.</span><span class='hs-conid'>ST</span> <span class='hs-layout'>(</span><span class='hs-varid'>unsafeIOToST</span><span class='hs-layout'>)</span>
<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'>Text</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span> <span class='hs-layout'>(</span><span class='hs-conid'>Text</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>empty</span><span class='hs-layout'>)</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'>Text</span><span class='hs-varop'>.</span><span class='hs-conid'>Unsafe</span> <span class='hs-layout'>(</span><span class='hs-varid'>lengthWord16</span><span class='hs-layout'>)</span>
<a name="line-38"></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'>Text</span><span class='hs-varop'>.</span><span class='hs-conid'>Array</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>A</span>
<a name="line-39"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Word</span> <span class='hs-layout'>(</span><span class='hs-conid'>Word16</span><span class='hs-layout'>)</span>
<a name="line-40"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Alloc</span> <span class='hs-layout'>(</span><span class='hs-varid'>allocaBytes</span><span class='hs-layout'>)</span>
<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'>Ptr</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ptr</span><span class='hs-layout'>,</span> <span class='hs-varid'>castPtr</span><span class='hs-layout'>,</span> <span class='hs-varid'>plusPtr</span><span class='hs-layout'>)</span>
<a name="line-42"></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-varid'>peek</span><span class='hs-layout'>,</span> <span class='hs-varid'>poke</span><span class='hs-layout'>)</span>
<a name="line-43"></a>
<a name="line-44"></a><span class='hs-comment'>-- $interop</span>
<a name="line-45"></a><span class='hs-comment'>--</span>
<a name="line-46"></a><span class='hs-comment'>-- The 'Text' type is implemented using arrays that are not guaranteed</span>
<a name="line-47"></a><span class='hs-comment'>-- to have a fixed address in the Haskell heap. All communication with</span>
<a name="line-48"></a><span class='hs-comment'>-- native code must thus occur by copying data back and forth.</span>
<a name="line-49"></a><span class='hs-comment'>--</span>
<a name="line-50"></a><span class='hs-comment'>-- The 'Text' type's internal representation is UTF-16, using the</span>
<a name="line-51"></a><span class='hs-comment'>-- platform's native endianness. This makes copied data suitable for</span>
<a name="line-52"></a><span class='hs-comment'>-- use with native libraries that use a similar representation, such</span>
<a name="line-53"></a><span class='hs-comment'>-- as ICU. To interoperate with native libraries that use different</span>
<a name="line-54"></a><span class='hs-comment'>-- internal representations, such as UTF-8 or UTF-32, consider using</span>
<a name="line-55"></a><span class='hs-comment'>-- the functions in the 'Data.Text.Encoding' module.</span>
<a name="line-56"></a>
<a name="line-57"></a><a name="fromPtr"></a><span class='hs-comment'>-- | /O(n)/ Create a new 'Text' from a 'Ptr' 'Word16' by copying the</span>
<a name="line-58"></a><span class='hs-comment'>-- contents of the array.</span>
<a name="line-59"></a><span class='hs-definition'>fromPtr</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Ptr</span> <span class='hs-conid'>Word16</span> <span class='hs-comment'>-- ^ source array</span>
<a name="line-60"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span> <span class='hs-comment'>-- ^ length of source array (in 'Word16' units)</span>
<a name="line-61"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Text</span>
<a name="line-62"></a><span class='hs-definition'>fromPtr</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-varid'>empty</span>
<a name="line-63"></a><span class='hs-definition'>fromPtr</span> <span class='hs-varid'>ptr</span> <span class='hs-varid'>len</span> <span class='hs-keyglyph'>=</span>
<a name="line-64"></a><span class='hs-cpp'>#if defined(ASSERTS)</span>
<a name="line-65"></a> <span class='hs-varid'>assert</span> <span class='hs-layout'>(</span><span class='hs-varid'>len</span> <span class='hs-varop'>></span> <span class='hs-num'>0</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-66"></a><span class='hs-cpp'>#endif</span>
<a name="line-67"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$!</span> <span class='hs-conid'>Text</span> <span class='hs-varid'>arr</span> <span class='hs-num'>0</span> <span class='hs-varid'>len</span>
<a name="line-68"></a> <span class='hs-keyword'>where</span>
<a name="line-69"></a> <span class='hs-varid'>arr</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>A</span><span class='hs-varop'>.</span><span class='hs-varid'>run</span> <span class='hs-layout'>(</span><span class='hs-conid'>A</span><span class='hs-varop'>.</span><span class='hs-varid'>unsafeNew</span> <span class='hs-varid'>len</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>copy</span><span class='hs-layout'>)</span>
<a name="line-70"></a> <span class='hs-varid'>copy</span> <span class='hs-varid'>marr</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>loop</span> <span class='hs-varid'>ptr</span> <span class='hs-num'>0</span>
<a name="line-71"></a> <span class='hs-keyword'>where</span>
<a name="line-72"></a> <span class='hs-varid'>loop</span> <span class='hs-varop'>!</span><span class='hs-varid'>p</span> <span class='hs-varop'>!</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>i</span> <span class='hs-varop'>==</span> <span class='hs-varid'>len</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varid'>marr</span>
<a name="line-73"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-74"></a> <span class='hs-conid'>A</span><span class='hs-varop'>.</span><span class='hs-varid'>unsafeWrite</span> <span class='hs-varid'>marr</span> <span class='hs-varid'>i</span> <span class='hs-varop'>=<<</span> <span class='hs-varid'>unsafeIOToST</span> <span class='hs-layout'>(</span><span class='hs-varid'>peek</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span>
<a name="line-75"></a> <span class='hs-varid'>loop</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-varop'>`plusPtr`</span> <span class='hs-num'>2</span><span class='hs-layout'>)</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>
<a name="line-76"></a>
<a name="line-77"></a><span class='hs-comment'>-- $lowlevel</span>
<a name="line-78"></a><span class='hs-comment'>--</span>
<a name="line-79"></a><span class='hs-comment'>-- Foreign functions that use UTF-16 internally may return indices in</span>
<a name="line-80"></a><span class='hs-comment'>-- units of 'Word16' instead of characters. These functions may</span>
<a name="line-81"></a><span class='hs-comment'>-- safely be used with such indices, as they will adjust offsets if</span>
<a name="line-82"></a><span class='hs-comment'>-- necessary to preserve the validity of a Unicode string.</span>
<a name="line-83"></a>
<a name="line-84"></a><a name="takeWord16"></a><span class='hs-comment'>-- | /O(1)/ Return the prefix of the 'Text' of @n@ 'Word16' units in</span>
<a name="line-85"></a><span class='hs-comment'>-- length.</span>
<a name="line-86"></a><span class='hs-comment'>--</span>
<a name="line-87"></a><span class='hs-comment'>-- If @n@ would cause the 'Text' to end inside a surrogate pair, the</span>
<a name="line-88"></a><span class='hs-comment'>-- end of the prefix will be advanced by one additional 'Word16' unit</span>
<a name="line-89"></a><span class='hs-comment'>-- to maintain its validity.</span>
<a name="line-90"></a><span class='hs-definition'>takeWord16</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Text</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Text</span>
<a name="line-91"></a><span class='hs-definition'>takeWord16</span> <span class='hs-varid'>n</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Text</span> <span class='hs-varid'>arr</span> <span class='hs-varid'>off</span> <span class='hs-varid'>len</span><span class='hs-layout'>)</span>
<a name="line-92"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>n</span> <span class='hs-varop'><=</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>empty</span>
<a name="line-93"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>n</span> <span class='hs-varop'>>=</span> <span class='hs-varid'>len</span> <span class='hs-varop'>||</span> <span class='hs-varid'>m</span> <span class='hs-varop'>>=</span> <span class='hs-varid'>len</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t</span>
<a name="line-94"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Text</span> <span class='hs-varid'>arr</span> <span class='hs-varid'>off</span> <span class='hs-varid'>m</span>
<a name="line-95"></a> <span class='hs-keyword'>where</span>
<a name="line-96"></a> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>w</span> <span class='hs-varop'><</span> <span class='hs-num'>0xDB00</span> <span class='hs-varop'>||</span> <span class='hs-varid'>w</span> <span class='hs-varop'>></span> <span class='hs-num'>0xD8FF</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>n</span>
<a name="line-97"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>n</span><span class='hs-varop'>+</span><span class='hs-num'>1</span>
<a name="line-98"></a> <span class='hs-varid'>w</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>A</span><span class='hs-varop'>.</span><span class='hs-varid'>unsafeIndex</span> <span class='hs-varid'>arr</span> <span class='hs-layout'>(</span><span class='hs-varid'>off</span><span class='hs-varop'>+</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-99"></a>
<a name="line-100"></a><a name="dropWord16"></a><span class='hs-comment'>-- | /O(1)/ Return the suffix of the 'Text', with @n@ 'Word16' units</span>
<a name="line-101"></a><span class='hs-comment'>-- dropped from its beginning.</span>
<a name="line-102"></a><span class='hs-comment'>--</span>
<a name="line-103"></a><span class='hs-comment'>-- If @n@ would cause the 'Text' to begin inside a surrogate pair, the</span>
<a name="line-104"></a><span class='hs-comment'>-- beginning of the suffix will be advanced by one additional 'Word16'</span>
<a name="line-105"></a><span class='hs-comment'>-- unit to maintain its validity.</span>
<a name="line-106"></a><span class='hs-definition'>dropWord16</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Text</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Text</span>
<a name="line-107"></a><span class='hs-definition'>dropWord16</span> <span class='hs-varid'>n</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Text</span> <span class='hs-varid'>arr</span> <span class='hs-varid'>off</span> <span class='hs-varid'>len</span><span class='hs-layout'>)</span>
<a name="line-108"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>n</span> <span class='hs-varop'><=</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t</span>
<a name="line-109"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>n</span> <span class='hs-varop'>>=</span> <span class='hs-varid'>len</span> <span class='hs-varop'>||</span> <span class='hs-varid'>m</span> <span class='hs-varop'>>=</span> <span class='hs-varid'>len</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>empty</span>
<a name="line-110"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Text</span> <span class='hs-varid'>arr</span> <span class='hs-layout'>(</span><span class='hs-varid'>off</span><span class='hs-varop'>+</span><span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>len</span><span class='hs-comment'>-</span><span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-111"></a> <span class='hs-keyword'>where</span>
<a name="line-112"></a> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>w</span> <span class='hs-varop'><</span> <span class='hs-num'>0xD800</span> <span class='hs-varop'>||</span> <span class='hs-varid'>w</span> <span class='hs-varop'>></span> <span class='hs-num'>0xDBFF</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>n</span>
<a name="line-113"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>n</span><span class='hs-varop'>+</span><span class='hs-num'>1</span>
<a name="line-114"></a> <span class='hs-varid'>w</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>A</span><span class='hs-varop'>.</span><span class='hs-varid'>unsafeIndex</span> <span class='hs-varid'>arr</span> <span class='hs-layout'>(</span><span class='hs-varid'>off</span><span class='hs-varop'>+</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-115"></a>
<a name="line-116"></a><a name="unsafeCopyToPtr"></a><span class='hs-comment'>-- | /O(n)/ Copy a 'Text' to an array. The array is assumed to be big</span>
<a name="line-117"></a><span class='hs-comment'>-- enough to hold the contents of the entire 'Text'.</span>
<a name="line-118"></a><span class='hs-definition'>unsafeCopyToPtr</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Text</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Ptr</span> <span class='hs-conid'>Word16</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-119"></a><span class='hs-definition'>unsafeCopyToPtr</span> <span class='hs-layout'>(</span><span class='hs-conid'>Text</span> <span class='hs-varid'>arr</span> <span class='hs-varid'>off</span> <span class='hs-varid'>len</span><span class='hs-layout'>)</span> <span class='hs-varid'>ptr</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>loop</span> <span class='hs-varid'>ptr</span> <span class='hs-varid'>off</span>
<a name="line-120"></a> <span class='hs-keyword'>where</span>
<a name="line-121"></a> <span class='hs-varid'>end</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>off</span> <span class='hs-varop'>+</span> <span class='hs-varid'>len</span>
<a name="line-122"></a> <span class='hs-varid'>loop</span> <span class='hs-varop'>!</span><span class='hs-varid'>p</span> <span class='hs-varop'>!</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>i</span> <span class='hs-varop'>==</span> <span class='hs-varid'>end</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-123"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-124"></a> <span class='hs-varid'>poke</span> <span class='hs-varid'>p</span> <span class='hs-layout'>(</span><span class='hs-conid'>A</span><span class='hs-varop'>.</span><span class='hs-varid'>unsafeIndex</span> <span class='hs-varid'>arr</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-125"></a> <span class='hs-varid'>loop</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-varop'>`plusPtr`</span> <span class='hs-num'>2</span><span class='hs-layout'>)</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>
<a name="line-126"></a>
<a name="line-127"></a><a name="useAsPtr"></a><span class='hs-comment'>-- | /O(n)/ Perform an action on a temporary, mutable copy of a</span>
<a name="line-128"></a><span class='hs-comment'>-- 'Text'. The copy is freed as soon as the action returns.</span>
<a name="line-129"></a><span class='hs-definition'>useAsPtr</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Text</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Ptr</span> <span class='hs-conid'>Word16</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span>
<a name="line-130"></a><span class='hs-definition'>useAsPtr</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Text</span> <span class='hs-sel'>_arr</span> <span class='hs-sel'>_off</span> <span class='hs-varid'>len</span><span class='hs-layout'>)</span> <span class='hs-varid'>action</span> <span class='hs-keyglyph'>=</span>
<a name="line-131"></a> <span class='hs-varid'>allocaBytes</span> <span class='hs-layout'>(</span><span class='hs-varid'>len</span> <span class='hs-varop'>*</span> <span class='hs-num'>2</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>buf</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-132"></a> <span class='hs-varid'>unsafeCopyToPtr</span> <span class='hs-varid'>t</span> <span class='hs-varid'>buf</span>
<a name="line-133"></a> <span class='hs-varid'>action</span> <span class='hs-layout'>(</span><span class='hs-varid'>castPtr</span> <span class='hs-varid'>buf</span><span class='hs-layout'>)</span> <span class='hs-varid'>len</span>
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