<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html> <head> <!-- Generated by HsColour, http://www.cs.york.ac.uk/fp/darcs/hscolour/ --> <title>Data/Text/UnsafeShift.hs</title> <link type='text/css' rel='stylesheet' href='hscolour.css' /> </head> <body> <pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE MagicHash #-}</span> <a name="line-2"></a> <a name="line-3"></a><span class='hs-comment'>-- |</span> <a name="line-4"></a><span class='hs-comment'>-- Module : Data.Text.UnsafeShift</span> <a name="line-5"></a><span class='hs-comment'>-- Copyright : (c) Bryan O'Sullivan 2009</span> <a name="line-6"></a><span class='hs-comment'>--</span> <a name="line-7"></a><span class='hs-comment'>-- License : BSD-style</span> <a name="line-8"></a><span class='hs-comment'>-- Maintainer : bos@serpentine.com, rtomharper@googlemail.com,</span> <a name="line-9"></a><span class='hs-comment'>-- duncan@haskell.org</span> <a name="line-10"></a><span class='hs-comment'>-- Stability : experimental</span> <a name="line-11"></a><span class='hs-comment'>-- Portability : GHC</span> <a name="line-12"></a><span class='hs-comment'>--</span> <a name="line-13"></a><span class='hs-comment'>-- Fast, unchecked bit shifting functions.</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'>UnsafeShift</span> <a name="line-16"></a> <span class='hs-layout'>(</span> <a name="line-17"></a> <span class='hs-conid'>UnsafeShift</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span> <a name="line-18"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <a name="line-19"></a> <a name="line-20"></a><span class='hs-comment'>-- import qualified Data.Bits as Bits</span> <a name="line-21"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>GHC</span><span class='hs-varop'>.</span><span class='hs-conid'>Base</span> <a name="line-22"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>GHC</span><span class='hs-varop'>.</span><span class='hs-conid'>Word</span> <a name="line-23"></a> <a name="line-24"></a><a name="UnsafeShift"></a><span class='hs-comment'>-- | This is a workaround for poor optimisation in GHC 6.8.2. It</span> <a name="line-25"></a><a name="UnsafeShift"></a><span class='hs-comment'>-- fails to notice constant-width shifts, and adds a test and branch</span> <a name="line-26"></a><a name="UnsafeShift"></a><span class='hs-comment'>-- to every shift. This imposes about a 10% performance hit.</span> <a name="line-27"></a><a name="UnsafeShift"></a><span class='hs-comment'>--</span> <a name="line-28"></a><a name="UnsafeShift"></a><span class='hs-comment'>-- These functions are undefined when the amount being shifted by is</span> <a name="line-29"></a><a name="UnsafeShift"></a><span class='hs-comment'>-- greater than the size in bits of a machine Int#.</span> <a name="line-30"></a><a name="UnsafeShift"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>UnsafeShift</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>where</span> <a name="line-31"></a> <span class='hs-varid'>shiftL</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <a name="line-32"></a> <span class='hs-varid'>shiftR</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <a name="line-33"></a> <a name="line-34"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>UnsafeShift</span> <span class='hs-conid'>Word16</span> <span class='hs-keyword'>where</span> <a name="line-35"></a> <span class='hs-comment'>{-# INLINE shiftL #-}</span> <a name="line-36"></a> <span class='hs-varid'>shiftL</span> <span class='hs-layout'>(</span><span class='hs-conid'>W16</span><span class='hs-cpp'>#</span> <span class='hs-varid'>x</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W16</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>narrow16Word</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-cpp'>#</span> <span class='hs-varop'>`</span><span class='hs-varid'>uncheckedShiftL</span><span class='hs-cpp'>#</span><span class='hs-varop'>`</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-37"></a> <a name="line-38"></a> <span class='hs-comment'>{-# INLINE shiftR #-}</span> <a name="line-39"></a> <span class='hs-varid'>shiftR</span> <span class='hs-layout'>(</span><span class='hs-conid'>W16</span><span class='hs-cpp'>#</span> <span class='hs-varid'>x</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W16</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-cpp'>#</span> <span class='hs-varop'>`</span><span class='hs-varid'>uncheckedShiftRL</span><span class='hs-cpp'>#</span><span class='hs-varop'>`</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <a name="line-40"></a> <a name="line-41"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>UnsafeShift</span> <span class='hs-conid'>Word32</span> <span class='hs-keyword'>where</span> <a name="line-42"></a> <span class='hs-comment'>{-# INLINE shiftL #-}</span> <a name="line-43"></a> <span class='hs-varid'>shiftL</span> <span class='hs-layout'>(</span><span class='hs-conid'>W32</span><span class='hs-cpp'>#</span> <span class='hs-varid'>x</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W32</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>narrow32Word</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-cpp'>#</span> <span class='hs-varop'>`</span><span class='hs-varid'>uncheckedShiftL</span><span class='hs-cpp'>#</span><span class='hs-varop'>`</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-44"></a> <a name="line-45"></a> <span class='hs-comment'>{-# INLINE shiftR #-}</span> <a name="line-46"></a> <span class='hs-varid'>shiftR</span> <span class='hs-layout'>(</span><span class='hs-conid'>W32</span><span class='hs-cpp'>#</span> <span class='hs-varid'>x</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W32</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-cpp'>#</span> <span class='hs-varop'>`</span><span class='hs-varid'>uncheckedShiftRL</span><span class='hs-cpp'>#</span><span class='hs-varop'>`</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <a name="line-47"></a> <a name="line-48"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>UnsafeShift</span> <span class='hs-conid'>Word64</span> <span class='hs-keyword'>where</span> <a name="line-49"></a> <span class='hs-comment'>{-# INLINE shiftL #-}</span> <a name="line-50"></a> <span class='hs-varid'>shiftL</span> <span class='hs-layout'>(</span><span class='hs-conid'>W64</span><span class='hs-cpp'>#</span> <span class='hs-varid'>x</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W64</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-cpp'>#</span> <span class='hs-varop'>`</span><span class='hs-varid'>uncheckedShiftL64</span><span class='hs-cpp'>#</span><span class='hs-varop'>`</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <a name="line-51"></a> <a name="line-52"></a> <span class='hs-comment'>{-# INLINE shiftR #-}</span> <a name="line-53"></a> <span class='hs-varid'>shiftR</span> <span class='hs-layout'>(</span><span class='hs-conid'>W64</span><span class='hs-cpp'>#</span> <span class='hs-varid'>x</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W64</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-cpp'>#</span> <span class='hs-varop'>`</span><span class='hs-varid'>uncheckedShiftRL64</span><span class='hs-cpp'>#</span><span class='hs-varop'>`</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <a name="line-54"></a> <a name="line-55"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>UnsafeShift</span> <span class='hs-conid'>Int</span> <span class='hs-keyword'>where</span> <a name="line-56"></a> <span class='hs-comment'>{-# INLINE shiftL #-}</span> <a name="line-57"></a> <span class='hs-varid'>shiftL</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>x</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-cpp'>#</span> <span class='hs-varop'>`</span><span class='hs-varid'>iShiftL</span><span class='hs-cpp'>#</span><span class='hs-varop'>`</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <a name="line-58"></a> <a name="line-59"></a> <span class='hs-comment'>{-# INLINE shiftR #-}</span> <a name="line-60"></a> <span class='hs-varid'>shiftR</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>x</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>I</span><span class='hs-cpp'>#</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-cpp'>#</span> <span class='hs-varop'>`</span><span class='hs-varid'>iShiftRA</span><span class='hs-cpp'>#</span><span class='hs-varop'>`</span> <span class='hs-varid'>i</span><span class='hs-cpp'>#</span><span class='hs-layout'>)</span> <a name="line-61"></a> <a name="line-62"></a><span class='hs-comment'>{- <a name="line-63"></a>instance UnsafeShift Integer where <a name="line-64"></a> {-# INLINE shiftL #-} <a name="line-65"></a> shiftL = Bits.shiftL <a name="line-66"></a> <a name="line-67"></a> {-# INLINE shiftR #-} <a name="line-68"></a> shiftR = Bits.shiftR <a name="line-69"></a>-}</span> </pre></body> </html>