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<div id="projectname">libaaruformat<span id="projectnumber">&#160;1.0</span>
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<div id="projectbrief">Aaru Data Preservation Suite - Format Library</div>
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<div class="textblock"><code>#include &lt;stddef.h&gt;</code><br />
<code>#include &lt;stdint.h&gt;</code><br />
</div>
<p><a href="gf256_8h_source.html">Go to the source code of this file.</a></p>
<table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 id="header-func-members" class="groupheader"><a id="func-members" name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:af1afff8141cfc915bb37fc01dab39995" id="r_af1afff8141cfc915bb37fc01dab39995"><td class="memItemLeft">uint8_t&#160;</td><td class="memItemRight"><a class="el" href="#af1afff8141cfc915bb37fc01dab39995">gf256_mul</a> (uint8_t a, uint8_t b)</td></tr>
<tr class="memdesc:af1afff8141cfc915bb37fc01dab39995"><td class="mdescLeft">&#160;</td><td class="mdescRight">Multiply two elements in GF(2^8) with polynomial 0x11D. <br /></td></tr>
<tr class="memitem:a1f0071a2ea261bdd2a59cc757a3ce13c" id="r_a1f0071a2ea261bdd2a59cc757a3ce13c"><td class="memItemLeft">uint8_t&#160;</td><td class="memItemRight"><a class="el" href="#a1f0071a2ea261bdd2a59cc757a3ce13c">gf256_div</a> (uint8_t a, uint8_t b)</td></tr>
<tr class="memdesc:a1f0071a2ea261bdd2a59cc757a3ce13c"><td class="mdescLeft">&#160;</td><td class="mdescRight">Divide two elements in GF(2^8). <br /></td></tr>
<tr class="memitem:a43b3c7a9e2c10d25670fd961ae2916ca" id="r_a43b3c7a9e2c10d25670fd961ae2916ca"><td class="memItemLeft">uint8_t&#160;</td><td class="memItemRight"><a class="el" href="#a43b3c7a9e2c10d25670fd961ae2916ca">gf256_inv</a> (uint8_t a)</td></tr>
<tr class="memdesc:a43b3c7a9e2c10d25670fd961ae2916ca"><td class="mdescLeft">&#160;</td><td class="mdescRight">Compute multiplicative inverse in GF(2^8). <br /></td></tr>
<tr class="memitem:ad9ea1dd38b7a45e2c9f967c26d7b05df" id="r_ad9ea1dd38b7a45e2c9f967c26d7b05df"><td class="memItemLeft">void&#160;</td><td class="memItemRight"><a class="el" href="#ad9ea1dd38b7a45e2c9f967c26d7b05df">gf256_mul_region</a> (uint8_t *dst, const uint8_t *src, uint8_t coeff, size_t len)</td></tr>
<tr class="memdesc:ad9ea1dd38b7a45e2c9f967c26d7b05df"><td class="mdescLeft">&#160;</td><td class="mdescRight">Multiply-accumulate a region: dst[i] ^= GF_mul(src[i], coeff) for all i. <br /></td></tr>
<tr class="memitem:a2e7b136d97e3214ff718f46542e276da" id="r_a2e7b136d97e3214ff718f46542e276da"><td class="memItemLeft">void&#160;</td><td class="memItemRight"><a class="el" href="#a2e7b136d97e3214ff718f46542e276da">gf256_xor_region</a> (uint8_t *dst, const uint8_t *src, size_t len)</td></tr>
<tr class="memdesc:a2e7b136d97e3214ff718f46542e276da"><td class="mdescLeft">&#160;</td><td class="mdescRight">XOR a region: dst[i] ^= src[i] for all i. <br /></td></tr>
</table>
<a name="doc-func-members" id="doc-func-members"></a><h2 id="header-doc-func-members" class="groupheader">Function Documentation</h2>
<a id="a1f0071a2ea261bdd2a59cc757a3ce13c" name="a1f0071a2ea261bdd2a59cc757a3ce13c"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a1f0071a2ea261bdd2a59cc757a3ce13c">&#9670;&#160;</a></span>gf256_div()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">uint8_t gf256_div </td>
<td>(</td>
<td class="paramtype">uint8_t</td> <td class="paramname"><span class="paramname"><em>a</em></span>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">uint8_t</td> <td class="paramname"><span class="paramname"><em>b</em></span>&#160;)</td>
</tr>
</table>
</div><div class="memdoc">
<p>Divide two elements in GF(2^8). </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">a</td><td>Dividend. </td></tr>
<tr><td class="paramname">b</td><td>Divisor (must be non-zero). </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>Quotient a/b in GF(2^8). </dd></dl>
<p class="definition">Definition at line <a class="el" href="gf256_8c_source.html#l00084">84</a> of file <a class="el" href="gf256_8c_source.html">gf256.c</a>.</p>
<p class="reference">References <a class="el" href="gf256_8c_source.html#l00043">gf256_exp_table</a>, <a class="el" href="gf256_8c_source.html#l00051">gf256_init_tables()</a>, and <a class="el" href="gf256_8c_source.html#l00041">gf256_log_table</a>.</p>
</div>
</div>
<a id="a43b3c7a9e2c10d25670fd961ae2916ca" name="a43b3c7a9e2c10d25670fd961ae2916ca"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a43b3c7a9e2c10d25670fd961ae2916ca">&#9670;&#160;</a></span>gf256_inv()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">uint8_t gf256_inv </td>
<td>(</td>
<td class="paramtype">uint8_t</td> <td class="paramname"><span class="paramname"><em>a</em></span></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Compute multiplicative inverse in GF(2^8). </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">a</td><td>Element (must be non-zero). </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>Inverse a^(-1) in GF(2^8). </dd></dl>
<p class="definition">Definition at line <a class="el" href="gf256_8c_source.html#l00092">92</a> of file <a class="el" href="gf256_8c_source.html">gf256.c</a>.</p>
<p class="reference">References <a class="el" href="gf256_8c_source.html#l00043">gf256_exp_table</a>, <a class="el" href="gf256_8c_source.html#l00051">gf256_init_tables()</a>, and <a class="el" href="gf256_8c_source.html#l00041">gf256_log_table</a>.</p>
<p class="reference">Referenced by <a class="el" href="reed__solomon_8c_source.html#l00084">invert_matrix()</a>.</p>
</div>
</div>
<a id="af1afff8141cfc915bb37fc01dab39995" name="af1afff8141cfc915bb37fc01dab39995"></a>
<h2 class="memtitle"><span class="permalink"><a href="#af1afff8141cfc915bb37fc01dab39995">&#9670;&#160;</a></span>gf256_mul()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">uint8_t gf256_mul </td>
<td>(</td>
<td class="paramtype">uint8_t</td> <td class="paramname"><span class="paramname"><em>a</em></span>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">uint8_t</td> <td class="paramname"><span class="paramname"><em>b</em></span>&#160;)</td>
</tr>
</table>
</div><div class="memdoc">
<p>Multiply two elements in GF(2^8) with polynomial 0x11D. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">a</td><td>First operand. </td></tr>
<tr><td class="paramname">b</td><td>Second operand. </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>Product a*b in GF(2^8). </dd></dl>
<p class="definition">Definition at line <a class="el" href="gf256_8c_source.html#l00077">77</a> of file <a class="el" href="gf256_8c_source.html">gf256.c</a>.</p>
<p class="reference">References <a class="el" href="gf256_8c_source.html#l00043">gf256_exp_table</a>, <a class="el" href="gf256_8c_source.html#l00051">gf256_init_tables()</a>, and <a class="el" href="gf256_8c_source.html#l00041">gf256_log_table</a>.</p>
<p class="reference">Referenced by <a class="el" href="reed__solomon_8c_source.html#l00058">build_vandermonde()</a>, <a class="el" href="gf256_8c_source.html#l00114">gf256_build_mul_tables()</a>, <a class="el" href="reed__solomon_8c_source.html#l00084">invert_matrix()</a>, <a class="el" href="reed__solomon_8c_source.html#l00150">rs_create()</a>, and <a class="el" href="reed__solomon_8c_source.html#l00218">rs_decode()</a>.</p>
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<a id="ad9ea1dd38b7a45e2c9f967c26d7b05df" name="ad9ea1dd38b7a45e2c9f967c26d7b05df"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ad9ea1dd38b7a45e2c9f967c26d7b05df">&#9670;&#160;</a></span>gf256_mul_region()</h2>
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<div class="memproto">
<table class="memname">
<tr>
<td class="memname">void gf256_mul_region </td>
<td>(</td>
<td class="paramtype">uint8_t *</td> <td class="paramname"><span class="paramname"><em>dst</em></span>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">const uint8_t *</td> <td class="paramname"><span class="paramname"><em>src</em></span>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">uint8_t</td> <td class="paramname"><span class="paramname"><em>coeff</em></span>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">size_t</td> <td class="paramname"><span class="paramname"><em>len</em></span>&#160;)</td>
</tr>
</table>
</div><div class="memdoc">
<p>Multiply-accumulate a region: dst[i] ^= GF_mul(src[i], coeff) for all i. </p>
<p>Uses SIMD acceleration when available (AVX2 &gt; SSSE3 &gt; NEON &gt; scalar). If coeff is 0, this is a no-op. If coeff is 1, this is XOR.</p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">dst</td><td>Destination buffer (read-modify-write). </td></tr>
<tr><td class="paramname">src</td><td>Source buffer (read-only). </td></tr>
<tr><td class="paramname">coeff</td><td>GF(2^8) coefficient. </td></tr>
<tr><td class="paramname">len</td><td>Number of bytes to process. </td></tr>
</table>
</dd>
</dl>
<p class="definition">Definition at line <a class="el" href="gf256_8c_source.html#l00324">324</a> of file <a class="el" href="gf256_8c_source.html">gf256.c</a>.</p>
<p class="reference">References <a class="el" href="gf256_8c_source.html#l00051">gf256_init_tables()</a>, <a class="el" href="gf256_8c_source.html#l00126">gf256_mul_region_scalar()</a>, and <a class="el" href="gf256_8c_source.html#l00344">gf256_xor_region()</a>.</p>
<p class="reference">Referenced by <a class="el" href="reed__solomon_8c_source.html#l00218">rs_decode()</a>, and <a class="el" href="reed__solomon_8c_source.html#l00213">rs_encode_incremental()</a>.</p>
</div>
</div>
<a id="a2e7b136d97e3214ff718f46542e276da" name="a2e7b136d97e3214ff718f46542e276da"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a2e7b136d97e3214ff718f46542e276da">&#9670;&#160;</a></span>gf256_xor_region()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">void gf256_xor_region </td>
<td>(</td>
<td class="paramtype">uint8_t *</td> <td class="paramname"><span class="paramname"><em>dst</em></span>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">const uint8_t *</td> <td class="paramname"><span class="paramname"><em>src</em></span>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">size_t</td> <td class="paramname"><span class="paramname"><em>len</em></span>&#160;)</td>
</tr>
</table>
</div><div class="memdoc">
<p>XOR a region: dst[i] ^= src[i] for all i. </p>
<p>Uses SIMD acceleration when available.</p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">dst</td><td>Destination buffer (read-modify-write). </td></tr>
<tr><td class="paramname">src</td><td>Source buffer (read-only). </td></tr>
<tr><td class="paramname">len</td><td>Number of bytes to process. </td></tr>
</table>
</dd>
</dl>
<p class="definition">Definition at line <a class="el" href="gf256_8c_source.html#l00344">344</a> of file <a class="el" href="gf256_8c_source.html">gf256.c</a>.</p>
<p class="reference">References <a class="el" href="gf256_8c_source.html#l00135">gf256_xor_region_scalar()</a>.</p>
<p class="reference">Referenced by <a class="el" href="gf256_8c_source.html#l00324">gf256_mul_region()</a>.</p>
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