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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::</span>byteswap</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-numeric.html">numeric</a></span></div>
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code><a href="cpp-header-bit.html">&lt;bit&gt;</a></code></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> T <span class="sy1">&gt;</span><br />
<span class="kw4">constexpr</span> T byteswap<span class="br0">(</span> T n <span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx23">(C++23 &#36215;)</span></td>
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<p>&#36870;&#36716;&#32473;&#23450;&#25972;&#25968;&#20540; <code>n</code> &#20013;&#30340;&#23383;&#33410;&#12290;</p>
<p><code>std::byteswap</code> &#20165;&#33509; <code>T</code> &#28385;&#36275; <a href="cpp-concepts-integral.html"><code>integral</code></a> &#65292;&#21363; <code>T</code> &#20026;&#25972;&#25968;&#31867;&#22411;&#25165;&#21442;&#19982;&#37325;&#36733;&#20915;&#35758;&#12290;&#33509; <code>T</code> &#25317;&#26377;&#22635;&#20805;&#20301;&#21017;&#31243;&#24207;&#38750;&#33391;&#26500;&#12290;</p>
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
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<td>n</td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p><code>T</code> &#31867;&#22411;&#25972;&#25968;&#20540;&#65292;&#20854;&#23545;&#35937;&#34920;&#31034;&#30001; <code>n</code> &#30340;&#23545;&#35937;&#34920;&#31034;&#30340;&#23383;&#33410;&#25353;&#36870;&#24207;&#32452;&#25104;&#12290;</p>
<h3><span class="mw-headline" id=".E6.B3.A8.E8.A7.A3">&#27880;&#35299;</span></h3>
<p>&#27492;&#20989;&#25968;&#23545;&#22788;&#29702;&#26377;&#19981;&#21516;&#31471;&#24207;&#30340;&#25968;&#25454;&#26377;&#29992;&#12290;</p>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
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<pre class="de1"><span class="co2">#include &lt;bit&gt;</span>
<span class="co2">#include &lt;cstdint&gt;</span>
<span class="co2">#include &lt;concepts&gt;</span>
<span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;iomanip&gt;</span>
<span class="kw1">template</span> <span class="sy1">&lt;</span>std<span class="sy4">::</span><span class="me2">integral</span> T<span class="sy1">&gt;</span>
<span class="kw4">void</span> dump<span class="br0">(</span>T v, <span class="kw4">char</span> term <span class="sy1">=</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="br0">)</span> <span class="br0">{</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-hex.html"><span class="kw1782">std::<span class="me2">hex</span></span></a> <span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-uppercase.html"><span class="kw1774">std::<span class="me2">uppercase</span></span></a> <span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-setfill.html"><span class="kw1795">std::<span class="me2">setfill</span></span></a><span class="br0">(</span><span class="st0">&#39;0&#39;</span><span class="br0">)</span>
<span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-setw.html"><span class="kw1797">std::<span class="me2">setw</span></span></a><span class="br0">(</span>sizeof<span class="br0">(</span>T<span class="br0">)</span> <span class="sy2">*</span> <span class="nu0">2</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> v <span class="sy1">&lt;&lt;</span> <span class="st0">&quot; : &quot;</span><span class="sy4">;</span>
<span class="kw1">for</span> <span class="br0">(</span><a href="cpp-types-size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> i<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span> i <span class="sy3">!</span><span class="sy1">=</span> sizeof<span class="br0">(</span>T<span class="br0">)</span><span class="sy4">;</span> <span class="sy2">++</span>i, v <span class="sy1">&gt;&gt;=</span> <span class="nu0">8</span><span class="br0">)</span> <span class="br0">{</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-setw.html"><span class="kw1797">std::<span class="me2">setw</span></span></a><span class="br0">(</span><span class="nu0">2</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="kw1">static_cast</span><span class="sy1">&lt;</span><span class="kw4">unsigned</span><span class="sy1">&gt;</span><span class="br0">(</span>T<span class="br0">(</span><span class="nu12">0xFF</span><span class="br0">)</span> <span class="sy3">&amp;</span> v<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39; &#39;</span><span class="sy4">;</span>
<span class="br0">}</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-hex.html"><span class="kw1781">std::<span class="me2">dec</span></span></a> <span class="sy1">&lt;&lt;</span> term<span class="sy4">;</span>
<span class="br0">}</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
static_assert<span class="br0">(</span>std<span class="sy4">::</span><span class="me2">byteswap</span><span class="br0">(</span><span class="st0">&#39;a&#39;</span><span class="br0">)</span> <span class="sy1">==</span> <span class="st0">&#39;a&#39;</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;byteswap for U16:<span class="es1">\n</span>&quot;</span><span class="sy4">;</span>
<span class="kw4">constexpr</span> <span class="kw4">auto</span> x <span class="sy1">=</span> <a href="cpp-types-integer.html"><span class="kw121">std::<span class="me2">uint16_t</span></span></a><span class="br0">(</span><span class="nu12">0xCAFE</span><span class="br0">)</span><span class="sy4">;</span>
dump<span class="br0">(</span>x<span class="br0">)</span><span class="sy4">;</span>
dump<span class="br0">(</span>std<span class="sy4">::</span><span class="me2">byteswap</span><span class="br0">(</span>x<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;<span class="es1">\n</span>byteswap for U32:<span class="es1">\n</span>&quot;</span><span class="sy4">;</span>
<span class="kw4">constexpr</span> <span class="kw4">auto</span> y <span class="sy1">=</span> <a href="cpp-types-integer.html"><span class="kw122">std::<span class="me2">uint32_t</span></span></a><span class="br0">(</span>0xDEADBEEFu<span class="br0">)</span><span class="sy4">;</span>
dump<span class="br0">(</span>y<span class="br0">)</span><span class="sy4">;</span>
dump<span class="br0">(</span>std<span class="sy4">::</span><span class="me2">byteswap</span><span class="br0">(</span>y<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;<span class="es1">\n</span>byteswap for U64:<span class="es1">\n</span>&quot;</span><span class="sy4">;</span>
<span class="kw4">constexpr</span> <span class="kw4">auto</span> z <span class="sy1">=</span> <a href="cpp-types-integer.html"><span class="kw123">std::<span class="me2">uint64_t</span></span></a><span class="br0">{</span>0x0123456789ABCDEFull<span class="br0">}</span><span class="sy4">;</span>
dump<span class="br0">(</span>z<span class="br0">)</span><span class="sy4">;</span>
dump<span class="br0">(</span>std<span class="sy4">::</span><span class="me2">byteswap</span><span class="br0">(</span>z<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div>
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<p>&#21487;&#33021;&#30340;&#36755;&#20986;&#65306;</p>
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<pre class="de1">byteswap for U16:
CAFE : FE CA
FECA : CA FE
byteswap for U32:
DEADBEEF : EF BE AD DE
EFBEADDE : DE AD BE EF
byteswap for U64:
0123456789ABCDEF : EF CD AB 89 67 45 23 01
EFCDAB8967452301 : 01 23 45 67 89 AB CD EF</pre></div>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
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<div><a href="cpp-types-endian.html"><span class="t-lines"><span>endian</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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<td>&#25351;&#31034;&#26631;&#37327;&#31867;&#22411;&#30340;&#31471;&#24207;<br />
<span class="t-mark">(&#26522;&#20030;)</span></td>
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<div class="t-dsc-member-div">
<div><a href="cpp-numeric-rotl.html"><span class="t-lines"><span>rotl</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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<td>&#35745;&#31639;&#36880;&#20301;&#24038;&#26059;&#36716;&#30340;&#32467;&#26524;<br />
<span class="t-mark">(&#20989;&#25968;&#27169;&#26495;)</span></td>
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<div><a href="cpp-numeric-rotr.html"><span class="t-lines"><span>rotr</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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<td>&#35745;&#31639;&#36880;&#20301;&#21491;&#26059;&#36716;&#30340;&#32467;&#26524;<br />
<span class="t-mark">(&#20989;&#25968;&#27169;&#26495;)</span></td>
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