gf2n_8cpp-source.html

著名的密码库Crypto++的文档 C++语言的杰作。程序员必备。

<a name="l00301"></a>00301                         remainder -= divisor;
<a name="l00302"></a>00302                         quotient.<a class="code" href="class_polynomial_mod2.html#b3855a5f77e9bbc7d82a4239ccf59329">SetBit</a>(i);
<a name="l00303"></a>00303                 }
<a name="l00304"></a>00304         }
<a name="l00305"></a>00305 }
<a name="l00306"></a>00306 
<a name="l00307"></a><a class="code" href="class_polynomial_mod2.html#91bb7fc668249f76ee3aea359daf0842">00307</a> <a class="code" href="class_polynomial_mod2.html" title="Polynomial with Coefficients in GF(2).">PolynomialMod2</a> <a class="code" href="class_polynomial_mod2.html#91bb7fc668249f76ee3aea359daf0842">PolynomialMod2::DividedBy</a>(<span class="keyword">const</span> <a class="code" href="class_polynomial_mod2.html" title="Polynomial with Coefficients in GF(2).">PolynomialMod2</a> &amp;b)<span class="keyword"> const</span>
<a name="l00308"></a>00308 <span class="keyword"></span>{
<a name="l00309"></a>00309         <a class="code" href="class_polynomial_mod2.html" title="Polynomial with Coefficients in GF(2).">PolynomialMod2</a> remainder, quotient;
<a name="l00310"></a>00310         <a class="code" href="class_polynomial_mod2.html#73d92da2ee829619041eca82567b87bc" title="calculate r and q such that (a == d*q + r) &amp;&amp; (deg(r) &lt; deg(d))">PolynomialMod2::Divide</a>(remainder, quotient, *<span class="keyword">this</span>, b);
<a name="l00311"></a>00311         <span class="keywordflow">return</span> quotient;
<a name="l00312"></a>00312 }
<a name="l00313"></a>00313 
<a name="l00314"></a><a class="code" href="class_polynomial_mod2.html#1e1e201da250b5fe9ee142705e14ffdc">00314</a> <a class="code" href="class_polynomial_mod2.html" title="Polynomial with Coefficients in GF(2).">PolynomialMod2</a> <a class="code" href="class_polynomial_mod2.html#1e1e201da250b5fe9ee142705e14ffdc">PolynomialMod2::Modulo</a>(<span class="keyword">const</span> <a class="code" href="class_polynomial_mod2.html" title="Polynomial with Coefficients in GF(2).">PolynomialMod2</a> &amp;b)<span class="keyword"> const</span>
<a name="l00315"></a>00315 <span class="keyword"></span>{
<a name="l00316"></a>00316         <a class="code" href="class_polynomial_mod2.html" title="Polynomial with Coefficients in GF(2).">PolynomialMod2</a> remainder, quotient;
<a name="l00317"></a>00317         <a class="code" href="class_polynomial_mod2.html#73d92da2ee829619041eca82567b87bc" title="calculate r and q such that (a == d*q + r) &amp;&amp; (deg(r) &lt; deg(d))">PolynomialMod2::Divide</a>(remainder, quotient, *<span class="keyword">this</span>, b);
<a name="l00318"></a>00318         <span class="keywordflow">return</span> remainder;
<a name="l00319"></a>00319 }
<a name="l00320"></a>00320 
<a name="l00321"></a><a class="code" href="class_polynomial_mod2.html#d73f6f1c7331f2b745c0d61f11d881b9">00321</a> <a class="code" href="class_polynomial_mod2.html" title="Polynomial with Coefficients in GF(2).">PolynomialMod2</a>&amp; <a class="code" href="class_polynomial_mod2.html#d73f6f1c7331f2b745c0d61f11d881b9">PolynomialMod2::operator&lt;&lt;=</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> n)
<a name="l00322"></a>00322 {
<a name="l00323"></a>00323         <span class="keywordflow">if</span> (!reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>())
<a name="l00324"></a>00324                 <span class="keywordflow">return</span> *<span class="keyword">this</span>;
<a name="l00325"></a>00325 
<a name="l00326"></a>00326         <span class="keywordtype">int</span> i;
<a name="l00327"></a>00327         word u;
<a name="l00328"></a>00328         word carry=0;
<a name="l00329"></a>00329         word *r=reg;
<a name="l00330"></a>00330 
<a name="l00331"></a>00331         <span class="keywordflow">if</span> (n==1)       <span class="comment">// special case code for most frequent case</span>
<a name="l00332"></a>00332         {
<a name="l00333"></a>00333                 i = (int)reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>();
<a name="l00334"></a>00334                 <span class="keywordflow">while</span> (i--)
<a name="l00335"></a>00335                 {
<a name="l00336"></a>00336                         u = *r;
<a name="l00337"></a>00337                         *r = (u &lt;&lt; 1) | carry;
<a name="l00338"></a>00338                         carry = u &gt;&gt; (WORD_BITS-1);
<a name="l00339"></a>00339                         r++;
<a name="l00340"></a>00340                 }
<a name="l00341"></a>00341 
<a name="l00342"></a>00342                 <span class="keywordflow">if</span> (carry)
<a name="l00343"></a>00343                 {
<a name="l00344"></a>00344                         reg.<a class="code" href="class_sec_block.html#8dea287fba8236b0979b52beece0ec1b" title="change size only if newSize &gt; current size. contents are preserved">Grow</a>(reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>()+1);
<a name="l00345"></a>00345                         reg[reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>()-1] = carry;
<a name="l00346"></a>00346                 }
<a name="l00347"></a>00347 
<a name="l00348"></a>00348                 <span class="keywordflow">return</span> *<span class="keyword">this</span>;
<a name="l00349"></a>00349         }
<a name="l00350"></a>00350 
<a name="l00351"></a>00351         <span class="keywordtype">int</span> shiftWords = n / WORD_BITS;
<a name="l00352"></a>00352         <span class="keywordtype">int</span> shiftBits = n % WORD_BITS;
<a name="l00353"></a>00353 
<a name="l00354"></a>00354         <span class="keywordflow">if</span> (shiftBits)
<a name="l00355"></a>00355         {
<a name="l00356"></a>00356                 i = (int)reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>();
<a name="l00357"></a>00357                 <span class="keywordflow">while</span> (i--)
<a name="l00358"></a>00358                 {
<a name="l00359"></a>00359                         u = *r;
<a name="l00360"></a>00360                         *r = (u &lt;&lt; shiftBits) | carry;
<a name="l00361"></a>00361                         carry = u &gt;&gt; (WORD_BITS-shiftBits);
<a name="l00362"></a>00362                         r++;
<a name="l00363"></a>00363                 }
<a name="l00364"></a>00364         }
<a name="l00365"></a>00365 
<a name="l00366"></a>00366         <span class="keywordflow">if</span> (carry)
<a name="l00367"></a>00367         {
<a name="l00368"></a>00368                 reg.<a class="code" href="class_sec_block.html#8dea287fba8236b0979b52beece0ec1b" title="change size only if newSize &gt; current size. contents are preserved">Grow</a>(reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>()+shiftWords+1);
<a name="l00369"></a>00369                 reg[reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>()-1] = carry;
<a name="l00370"></a>00370         }
<a name="l00371"></a>00371         <span class="keywordflow">else</span>
<a name="l00372"></a>00372                 reg.<a class="code" href="class_sec_block.html#8dea287fba8236b0979b52beece0ec1b" title="change size only if newSize &gt; current size. contents are preserved">Grow</a>(reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>()+shiftWords);
<a name="l00373"></a>00373 
<a name="l00374"></a>00374         <span class="keywordflow">if</span> (shiftWords)
<a name="l00375"></a>00375         {
<a name="l00376"></a>00376                 <span class="keywordflow">for</span> (i = (<span class="keywordtype">int</span>)reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>()-1; i&gt;=shiftWords; i--)
<a name="l00377"></a>00377                         reg[i] = reg[i-shiftWords];
<a name="l00378"></a>00378                 <span class="keywordflow">for</span> (; i&gt;=0; i--)
<a name="l00379"></a>00379                         reg[i] = 0;
<a name="l00380"></a>00380         }
<a name="l00381"></a>00381 
<a name="l00382"></a>00382         <span class="keywordflow">return</span> *<span class="keyword">this</span>;
<a name="l00383"></a>00383 }
<a name="l00384"></a>00384 
<a name="l00385"></a><a class="code" href="class_polynomial_mod2.html#16f09c3dcc4ac6019c4f42012b177a37">00385</a> <a class="code" href="class_polynomial_mod2.html" title="Polynomial with Coefficients in GF(2).">PolynomialMod2</a>&amp; <a class="code" href="class_polynomial_mod2.html#16f09c3dcc4ac6019c4f42012b177a37">PolynomialMod2::operator&gt;&gt;=</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> n)
<a name="l00386"></a>00386 {
<a name="l00387"></a>00387         <span class="keywordflow">if</span> (!reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>())
<a name="l00388"></a>00388                 <span class="keywordflow">return</span> *<span class="keyword">this</span>;
<a name="l00389"></a>00389 
<a name="l00390"></a>00390         <span class="keywordtype">int</span> shiftWords = n / WORD_BITS;
<a name="l00391"></a>00391         <span class="keywordtype">int</span> shiftBits = n % WORD_BITS;
<a name="l00392"></a>00392 
<a name="l00393"></a>00393         <span class="keywordtype">size_t</span> i;
<a name="l00394"></a>00394         word u;
<a name="l00395"></a>00395         word carry=0;
<a name="l00396"></a>00396         word *r=reg+reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>()-1;
<a name="l00397"></a>00397 
<a name="l00398"></a>00398         <span class="keywordflow">if</span> (shiftBits)
<a name="l00399"></a>00399         {
<a name="l00400"></a>00400                 i = reg.<a class="code" href="class_sec_block.html#f5999bffe3193e62719cc0792b0282a7">size</a>();
<a name="l00401"></a>00401                 <span class="keywordflow">while</span> (i--)
<a name="l00402"></a>00402                 {
<a name="l00403"></a>00403                         u = *r;
<a name="l00404"></a>00404                         *r = (u &gt;&gt; shiftBits) | carry;
<a name="l00405"></a>00405                         carry = u &lt;&lt; (WORD_BITS-shiftBits);
<a name="l00406"></a>00406                         r--;
<a name="l00407"></a>00407                 }