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<pre><a name="line-1"></a><span class='hs-comment'>{-
<a name="line-2"></a>Copyright (C) 2004-2005 John Goerzen <jgoerzen@complete.org>
<a name="line-3"></a>
<a name="line-4"></a>This program is free software; you can redistribute it and/or modify
<a name="line-5"></a>it under the terms of the GNU General Public License as published by
<a name="line-6"></a>the Free Software Foundation; either version 2 of the License, or
<a name="line-7"></a>(at your option) any later version.
<a name="line-8"></a>
<a name="line-9"></a>This program is distributed in the hope that it will be useful,
<a name="line-10"></a>but WITHOUT ANY WARRANTY; without even the implied warranty of
<a name="line-11"></a>MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
<a name="line-12"></a>GNU General Public License for more details.
<a name="line-13"></a>
<a name="line-14"></a>You should have received a copy of the GNU General Public License
<a name="line-15"></a>along with this program; if not, write to the Free Software
<a name="line-16"></a>Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
<a name="line-17"></a>-}</span>
<a name="line-18"></a>
<a name="line-19"></a><span class='hs-comment'>{- |
<a name="line-20"></a> Module : System.IO.Utils
<a name="line-21"></a> Copyright : Copyright (C) 2004-2006 John Goerzen
<a name="line-22"></a> License : GNU GPL, version 2 or above
<a name="line-23"></a>
<a name="line-24"></a> Maintainer : John Goerzen <jgoerzen@complete.org>
<a name="line-25"></a> Stability : provisional
<a name="line-26"></a> Portability: portable
<a name="line-27"></a>-}</span>
<a name="line-28"></a>
<a name="line-29"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Utils</span><span class='hs-layout'>(</span><span class='hs-comment'>-- * Entire File Handle Utilities</span>
<a name="line-30"></a> <span class='hs-comment'>-- ** Opened Handle Data Copying</span>
<a name="line-31"></a> <span class='hs-varid'>hCopy</span><span class='hs-layout'>,</span> <span class='hs-varid'>hCopyProgress</span><span class='hs-layout'>,</span> <span class='hs-varid'>hLineCopy</span><span class='hs-layout'>,</span> <span class='hs-varid'>lineCopy</span><span class='hs-layout'>,</span>
<a name="line-32"></a> <span class='hs-comment'>-- ** Disk File Data Copying</span>
<a name="line-33"></a> <span class='hs-varid'>copyFileLinesToFile</span><span class='hs-layout'>,</span>
<a name="line-34"></a> <span class='hs-comment'>-- * Line Processing Utilities</span>
<a name="line-35"></a> <span class='hs-varid'>hPutStrLns</span><span class='hs-layout'>,</span> <span class='hs-varid'>hGetLines</span><span class='hs-layout'>,</span>
<a name="line-36"></a> <span class='hs-comment'>-- * Lazy Interaction</span>
<a name="line-37"></a> <span class='hs-comment'>-- ** Character-based</span>
<a name="line-38"></a> <span class='hs-varid'>hInteract</span><span class='hs-layout'>,</span>
<a name="line-39"></a> <span class='hs-comment'>-- ** Line-based</span>
<a name="line-40"></a> <span class='hs-varid'>hLineInteract</span><span class='hs-layout'>,</span> <span class='hs-varid'>lineInteract</span><span class='hs-layout'>,</span>
<a name="line-41"></a> <span class='hs-comment'>-- ** Misc. Lazy</span>
<a name="line-42"></a> <span class='hs-varid'>lazyMapM</span><span class='hs-layout'>,</span>
<a name="line-43"></a> <span class='hs-comment'>-- * Optimizations</span>
<a name="line-44"></a> <span class='hs-varid'>optimizeForBatch</span><span class='hs-layout'>,</span> <span class='hs-varid'>optimizeForInteraction</span>
<a name="line-45"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-46"></a>
<a name="line-47"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Unsafe</span> <span class='hs-layout'>(</span><span class='hs-varid'>unsafeInterleaveIO</span><span class='hs-layout'>)</span>
<a name="line-48"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span>
<a name="line-49"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span> <span class='hs-layout'>(</span><span class='hs-varid'>genericLength</span><span class='hs-layout'>)</span>
<a name="line-50"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>HVIO</span>
<a name="line-51"></a>
<a name="line-52"></a><a name="hPutStrLns"></a><span class='hs-comment'>{- | Given a list of strings, output a line containing each item, adding
<a name="line-53"></a>newlines as appropriate. The list is not expected to have newlines already.
<a name="line-54"></a>-}</span>
<a name="line-55"></a><span class='hs-definition'>hPutStrLns</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>HVIO</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-56"></a><span class='hs-definition'>hPutStrLns</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mapM_</span> <span class='hs-varop'>$</span> <span class='hs-varid'>vPutStrLn</span> <span class='hs-varid'>h</span>
<a name="line-57"></a>
<a name="line-58"></a><span class='hs-comment'>{- | Given a handle, returns a list of all the lines in that handle.
<a name="line-59"></a>Thanks to lazy evaluation, this list does not have to be read all at once.
<a name="line-60"></a>
<a name="line-61"></a>Combined with 'hPutStrLns', this can make a powerful way to develop
<a name="line-62"></a>filters. See the 'lineInteract' function for more on that concept.
<a name="line-63"></a>
<a name="line-64"></a>Example:
<a name="line-65"></a>
<a name="line-66"></a>> main = do
<a name="line-67"></a>> l <- hGetLines stdin
<a name="line-68"></a>> hPutStrLns stdout $ filter (startswith "1") l
<a name="line-69"></a>
<a name="line-70"></a>-}</span>
<a name="line-71"></a>
<a name="line-72"></a><a name="hGetLines"></a><span class='hs-comment'>-- FIXME: does hGetContents h >>= return . lines not work?</span>
<a name="line-73"></a><span class='hs-definition'>hGetLines</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>HVIO</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span>
<a name="line-74"></a><span class='hs-definition'>hGetLines</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafeInterleaveIO</span> <span class='hs-layout'>(</span><span class='hs-keyword'>do</span>
<a name="line-75"></a> <span class='hs-varid'>ieof</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vIsEOF</span> <span class='hs-varid'>h</span>
<a name="line-76"></a> <span class='hs-keyword'>if</span> <span class='hs-layout'>(</span><span class='hs-varid'>ieof</span><span class='hs-layout'>)</span>
<a name="line-77"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-78"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>do</span>
<a name="line-79"></a> <span class='hs-varid'>line</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vGetLine</span> <span class='hs-varid'>h</span>
<a name="line-80"></a> <span class='hs-varid'>remainder</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>hGetLines</span> <span class='hs-varid'>h</span>
<a name="line-81"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>line</span> <span class='hs-conop'>:</span> <span class='hs-varid'>remainder</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-82"></a>
<a name="line-83"></a>
<a name="line-84"></a><a name="hInteract"></a><span class='hs-comment'>{- | This is similar to the built-in 'System.IO.interact', but works
<a name="line-85"></a>on any handle, not just stdin and stdout.
<a name="line-86"></a>
<a name="line-87"></a>In other words:
<a name="line-88"></a>
<a name="line-89"></a>> interact = hInteract stdin stdout
<a name="line-90"></a>-}</span>
<a name="line-91"></a><span class='hs-definition'>hInteract</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>HVIO</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>HVIO</span> <span class='hs-varid'>b</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-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-92"></a><span class='hs-definition'>hInteract</span> <span class='hs-varid'>finput</span> <span class='hs-varid'>foutput</span> <span class='hs-varid'>func</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-93"></a> <span class='hs-varid'>content</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vGetContents</span> <span class='hs-varid'>finput</span>
<a name="line-94"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-varid'>foutput</span> <span class='hs-layout'>(</span><span class='hs-varid'>func</span> <span class='hs-varid'>content</span><span class='hs-layout'>)</span>
<a name="line-95"></a>
<a name="line-96"></a><a name="lineInteract"></a><span class='hs-comment'>{- | Line-based interaction. This is similar to wrapping your
<a name="line-97"></a>interact functions with 'lines' and 'unlines'. This equality holds:
<a name="line-98"></a>
<a name="line-99"></a>> lineInteract = hLineInteract stdin stdout
<a name="line-100"></a>
<a name="line-101"></a>Here's an example:
<a name="line-102"></a>
<a name="line-103"></a>> main = lineInteract (filter (startswith "1"))
<a name="line-104"></a>
<a name="line-105"></a>This will act as a simple version of grep -- all lines that start with 1
<a name="line-106"></a>will be displayed; all others will be ignored.
<a name="line-107"></a>-}</span>
<a name="line-108"></a><span class='hs-definition'>lineInteract</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-109"></a><span class='hs-definition'>lineInteract</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hLineInteract</span> <span class='hs-varid'>stdin</span> <span class='hs-varid'>stdout</span>
<a name="line-110"></a>
<a name="line-111"></a><a name="hLineInteract"></a><span class='hs-comment'>{- | Line-based interaction over arbitrary handles. This is similar
<a name="line-112"></a>to wrapping hInteract with 'lines' and 'unlines'.
<a name="line-113"></a>
<a name="line-114"></a>One could view this function like this:
<a name="line-115"></a>
<a name="line-116"></a>> hLineInteract finput foutput func =
<a name="line-117"></a>> let newf = unlines . func . lines in
<a name="line-118"></a>> hInteract finput foutput newf
<a name="line-119"></a>
<a name="line-120"></a>Though the actual implementation is this for efficiency:
<a name="line-121"></a>
<a name="line-122"></a>> hLineInteract finput foutput func =
<a name="line-123"></a>> do
<a name="line-124"></a>> lines <- hGetLines finput
<a name="line-125"></a>> hPutStrLns foutput (func lines)
<a name="line-126"></a>-}</span>
<a name="line-127"></a><span class='hs-definition'>hLineInteract</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>HVIO</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>HVIO</span> <span class='hs-varid'>b</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-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-128"></a><span class='hs-definition'>hLineInteract</span> <span class='hs-varid'>finput</span> <span class='hs-varid'>foutput</span> <span class='hs-varid'>func</span> <span class='hs-keyglyph'>=</span>
<a name="line-129"></a> <span class='hs-keyword'>do</span>
<a name="line-130"></a> <span class='hs-varid'>lines</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>hGetLines</span> <span class='hs-varid'>finput</span>
<a name="line-131"></a> <span class='hs-varid'>hPutStrLns</span> <span class='hs-varid'>foutput</span> <span class='hs-layout'>(</span><span class='hs-varid'>func</span> <span class='hs-varid'>lines</span><span class='hs-layout'>)</span>
<a name="line-132"></a>
<a name="line-133"></a><a name="hCopy"></a><span class='hs-comment'>{- | Copies from one handle to another in raw mode (using
<a name="line-134"></a>hGetContents).
<a name="line-135"></a>-}</span>
<a name="line-136"></a><span class='hs-definition'>hCopy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>HVIO</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>HVIO</span> <span class='hs-varid'>b</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-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-137"></a><span class='hs-definition'>hCopy</span> <span class='hs-varid'>hin</span> <span class='hs-varid'>hout</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-138"></a> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vGetContents</span> <span class='hs-varid'>hin</span>
<a name="line-139"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-varid'>hout</span> <span class='hs-varid'>c</span>
<a name="line-140"></a>
<a name="line-141"></a><a name="hCopyProgress"></a><span class='hs-comment'>{- | Copies from one handle to another in raw mode (using hGetContents).
<a name="line-142"></a>Takes a function to provide progress updates to the user.
<a name="line-143"></a>-}</span>
<a name="line-144"></a><span class='hs-definition'>hCopyProgress</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>HVIO</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>HVIO</span> <span class='hs-varid'>c</span><span class='hs-layout'>,</span> <span class='hs-conid'>Integral</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span>
<a name="line-145"></a> <span class='hs-varid'>b</span> <span class='hs-comment'>-- ^ Input handle</span>
<a name="line-146"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-comment'>-- ^ Output handle</span>
<a name="line-147"></a> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Integer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- ^ Progress function -- the bool is always False unless this is the final call</span>
<a name="line-148"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span> <span class='hs-comment'>-- Block size</span>
<a name="line-149"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- Estimated file size (passed to func)</span>
<a name="line-150"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Integer</span> <span class='hs-comment'>-- Number of bytes copied</span>
<a name="line-151"></a><span class='hs-definition'>hCopyProgress</span> <span class='hs-varid'>hin</span> <span class='hs-varid'>hout</span> <span class='hs-varid'>func</span> <span class='hs-varid'>bsize</span> <span class='hs-varid'>estsize</span> <span class='hs-keyglyph'>=</span>
<a name="line-152"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>copyFunc</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Integer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Integer</span>
<a name="line-153"></a> <span class='hs-varid'>copyFunc</span> <span class='hs-conid'>[]</span> <span class='hs-varid'>count</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varid'>count</span>
<a name="line-154"></a> <span class='hs-varid'>copyFunc</span> <span class='hs-varid'>indata</span> <span class='hs-varid'>count</span> <span class='hs-keyglyph'>=</span>
<a name="line-155"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>block</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>take</span> <span class='hs-varid'>bsize</span> <span class='hs-varid'>indata</span>
<a name="line-156"></a> <span class='hs-varid'>remainder</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>drop</span> <span class='hs-varid'>bsize</span> <span class='hs-varid'>indata</span>
<a name="line-157"></a> <span class='hs-varid'>newcount</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>count</span> <span class='hs-varop'>+</span> <span class='hs-layout'>(</span><span class='hs-varid'>genericLength</span> <span class='hs-varid'>block</span><span class='hs-layout'>)</span>
<a name="line-158"></a> <span class='hs-keyword'>in</span>
<a name="line-159"></a> <span class='hs-keyword'>do</span>
<a name="line-160"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-varid'>hout</span> <span class='hs-varid'>block</span>
<a name="line-161"></a> <span class='hs-varid'>func</span> <span class='hs-varid'>estsize</span> <span class='hs-varid'>count</span> <span class='hs-conid'>False</span>
<a name="line-162"></a> <span class='hs-varid'>copyFunc</span> <span class='hs-varid'>remainder</span> <span class='hs-varid'>newcount</span>
<a name="line-163"></a> <span class='hs-keyword'>in</span>
<a name="line-164"></a> <span class='hs-keyword'>do</span>
<a name="line-165"></a> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vGetContents</span> <span class='hs-varid'>hin</span>
<a name="line-166"></a> <span class='hs-varid'>bytes</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>copyFunc</span> <span class='hs-varid'>c</span> <span class='hs-num'>0</span>
<a name="line-167"></a> <span class='hs-varid'>func</span> <span class='hs-varid'>estsize</span> <span class='hs-varid'>bytes</span> <span class='hs-conid'>True</span>
<a name="line-168"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>bytes</span>
<a name="line-169"></a>
<a name="line-170"></a><a name="hLineCopy"></a><span class='hs-comment'>{- | Copies from one handle to another in text mode (with lines).
<a name="line-171"></a>Like 'hBlockCopy', this implementation is nice:
<a name="line-172"></a>
<a name="line-173"></a>> hLineCopy hin hout = hLineInteract hin hout id
<a name="line-174"></a>-}</span>
<a name="line-175"></a><span class='hs-definition'>hLineCopy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>HVIO</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>HVIO</span> <span class='hs-varid'>b</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-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span><span class='hs-conid'>()</span>
<a name="line-176"></a><span class='hs-definition'>hLineCopy</span> <span class='hs-varid'>hin</span> <span class='hs-varid'>hout</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hLineInteract</span> <span class='hs-varid'>hin</span> <span class='hs-varid'>hout</span> <span class='hs-varid'>id</span>
<a name="line-177"></a>
<a name="line-178"></a><a name="lineCopy"></a><span class='hs-comment'>{- | Copies from 'stdin' to 'stdout' using lines. An alias for 'hLineCopy'
<a name="line-179"></a>over 'stdin' and 'stdout'. -}</span>
<a name="line-180"></a><span class='hs-definition'>lineCopy</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-181"></a><span class='hs-definition'>lineCopy</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hLineCopy</span> <span class='hs-varid'>stdin</span> <span class='hs-varid'>stdout</span>
<a name="line-182"></a>
<a name="line-183"></a><a name="copyFileLinesToFile"></a><span class='hs-comment'>{- | Copies one filename to another in text mode.
<a name="line-184"></a>
<a name="line-185"></a>Please note that the Unix permission bits are set at a default; you may
<a name="line-186"></a>need to adjust them after the copy yourself.
<a name="line-187"></a>
<a name="line-188"></a>This function is implemented using 'hLineCopy' internally. -}</span>
<a name="line-189"></a><span class='hs-definition'>copyFileLinesToFile</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>FilePath</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>FilePath</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-190"></a><span class='hs-definition'>copyFileLinesToFile</span> <span class='hs-varid'>infn</span> <span class='hs-varid'>outfn</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-191"></a> <span class='hs-varid'>hin</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>openFile</span> <span class='hs-varid'>infn</span> <span class='hs-conid'>ReadMode</span>
<a name="line-192"></a> <span class='hs-varid'>hout</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>openFile</span> <span class='hs-varid'>outfn</span> <span class='hs-conid'>WriteMode</span>
<a name="line-193"></a> <span class='hs-varid'>hLineCopy</span> <span class='hs-varid'>hin</span> <span class='hs-varid'>hout</span>
<a name="line-194"></a> <span class='hs-varid'>hClose</span> <span class='hs-varid'>hin</span>
<a name="line-195"></a> <span class='hs-varid'>hClose</span> <span class='hs-varid'>hout</span>
<a name="line-196"></a> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-197"></a>
<a name="line-198"></a><a name="optimizeForBatch"></a><span class='hs-comment'>{- | Sets stdin and stdout to be block-buffered. This can save a huge amount
<a name="line-199"></a>of system resources since far fewer syscalls are made, and can make programs
<a name="line-200"></a>run much faster. -}</span>
<a name="line-201"></a><span class='hs-definition'>optimizeForBatch</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-202"></a><span class='hs-definition'>optimizeForBatch</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-203"></a> <span class='hs-varid'>hSetBuffering</span> <span class='hs-varid'>stdin</span> <span class='hs-layout'>(</span><span class='hs-conid'>BlockBuffering</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-num'>4096</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-204"></a> <span class='hs-varid'>hSetBuffering</span> <span class='hs-varid'>stdout</span> <span class='hs-layout'>(</span><span class='hs-conid'>BlockBuffering</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-num'>4096</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-205"></a>
<a name="line-206"></a><a name="optimizeForInteraction"></a><span class='hs-comment'>{- | Sets stdin and stdout to be line-buffered. This saves resources
<a name="line-207"></a>on stdout, but not many on stdin, since it it still looking for newlines. -}</span>
<a name="line-208"></a><span class='hs-definition'>optimizeForInteraction</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-209"></a><span class='hs-definition'>optimizeForInteraction</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-210"></a> <span class='hs-varid'>hSetBuffering</span> <span class='hs-varid'>stdin</span> <span class='hs-conid'>LineBuffering</span>
<a name="line-211"></a> <span class='hs-varid'>hSetBuffering</span> <span class='hs-varid'>stdout</span> <span class='hs-conid'>LineBuffering</span>
<a name="line-212"></a>
<a name="line-213"></a><a name="lazyMapM"></a><span class='hs-comment'>{- | Applies a given function to every item in a list, and returns
<a name="line-214"></a>the new list. Unlike the system\'s mapM, items are evaluated lazily. -}</span>
<a name="line-215"></a><span class='hs-definition'>lazyMapM</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'>IO</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span>
<a name="line-216"></a><span class='hs-definition'>lazyMapM</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-217"></a><span class='hs-definition'>lazyMapM</span> <span class='hs-varid'>conv</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-218"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>this</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>conv</span> <span class='hs-varid'>x</span>
<a name="line-219"></a> <span class='hs-varid'>next</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>unsafeInterleaveIO</span> <span class='hs-varop'>$</span> <span class='hs-varid'>lazyMapM</span> <span class='hs-varid'>conv</span> <span class='hs-varid'>xs</span>
<a name="line-220"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>this</span><span class='hs-conop'>:</span><span class='hs-varid'>next</span><span class='hs-layout'>)</span>
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