integer_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="l00236"></a>00236 
<a name="l00237"></a><a class="code" href="class_d_word.html#a2dd07047206457697e94ab8011f7958">00237</a>         <a class="code" href="class_d_word.html">DWord</a> <a class="code" href="class_d_word.html#159c633b6d08fc28b7babb58346d7a83">operator-</a>(word a)
<a name="l00238"></a>00238         {
<a name="l00239"></a>00239                 <a class="code" href="class_d_word.html">DWord</a> r;
<a name="l00240"></a>00240 <span class="preprocessor">                #ifdef CRYPTOPP_NATIVE_DWORD_AVAILABLE</span>
<a name="l00241"></a>00241 <span class="preprocessor"></span>                        r.<a class="code" href="class_d_word.html#f1503dcbfece6416389ad1ff69a0c10b">m_whole</a> = <a class="code" href="class_d_word.html#f1503dcbfece6416389ad1ff69a0c10b">m_whole</a> - a;
<a name="l00242"></a>00242 <span class="preprocessor">                #else</span>
<a name="l00243"></a>00243 <span class="preprocessor"></span>                        r.<a class="code" href="class_d_word.html#a96de257ecb1953d63b2818f5711d0ee">m_halfs</a>.low = m_halfs.low - a;
<a name="l00244"></a>00244                         r.<a class="code" href="class_d_word.html#a96de257ecb1953d63b2818f5711d0ee">m_halfs</a>.high = m_halfs.high - (r.<a class="code" href="class_d_word.html#a96de257ecb1953d63b2818f5711d0ee">m_halfs</a>.low &gt; m_halfs.low);
<a name="l00245"></a>00245 <span class="preprocessor">                #endif</span>
<a name="l00246"></a>00246 <span class="preprocessor"></span>                <span class="keywordflow">return</span> r;
<a name="l00247"></a>00247         }
<a name="l00248"></a>00248 
<a name="l00249"></a>00249         <span class="comment">// returns quotient, which must fit in a word</span>
<a name="l00250"></a>00250         word <a class="code" href="class_d_word.html#82597a869878e3924c9e7f03dc7ddcb1">operator/</a>(word divisor);
<a name="l00251"></a>00251 
<a name="l00252"></a>00252         word <a class="code" href="class_d_word.html#9dd87373f7a654e7fec14c7bc147f3eb">operator%</a>(word a);
<a name="l00253"></a>00253 
<a name="l00254"></a><a class="code" href="class_d_word.html#f7eeff45640d336e2dc0f58a8a3d0e5f">00254</a>         <span class="keywordtype">bool</span> <a class="code" href="class_d_word.html#f7eeff45640d336e2dc0f58a8a3d0e5f">operator!</a>()<span class="keyword"> const</span>
<a name="l00255"></a>00255 <span class="keyword">        </span>{
<a name="l00256"></a>00256 <span class="preprocessor">        #ifdef CRYPTOPP_NATIVE_DWORD_AVAILABLE</span>
<a name="l00257"></a>00257 <span class="preprocessor"></span>                <span class="keywordflow">return</span> !<a class="code" href="class_d_word.html#f1503dcbfece6416389ad1ff69a0c10b">m_whole</a>;
<a name="l00258"></a>00258 <span class="preprocessor">        #else</span>
<a name="l00259"></a>00259 <span class="preprocessor"></span>                <span class="keywordflow">return</span> !m_halfs.high &amp;&amp; !m_halfs.low;
<a name="l00260"></a>00260 <span class="preprocessor">        #endif</span>
<a name="l00261"></a>00261 <span class="preprocessor"></span>        }
<a name="l00262"></a>00262 
<a name="l00263"></a><a class="code" href="class_d_word.html#1320d87acfba9cb0b954de7b9ab1a3ad">00263</a>         word <a class="code" href="class_d_word.html#1320d87acfba9cb0b954de7b9ab1a3ad">GetLowHalf</a>()<span class="keyword"> const </span>{<span class="keywordflow">return</span> m_halfs.low;}
<a name="l00264"></a><a class="code" href="class_d_word.html#2a572c34533f004ab4753188558738a3">00264</a>         word <a class="code" href="class_d_word.html#2a572c34533f004ab4753188558738a3">GetHighHalf</a>()<span class="keyword"> const </span>{<span class="keywordflow">return</span> m_halfs.high;}
<a name="l00265"></a><a class="code" href="class_d_word.html#0a7727f1cc7d67635b8c8df68b374380">00265</a>         word <a class="code" href="class_d_word.html#0a7727f1cc7d67635b8c8df68b374380">GetHighHalfAsBorrow</a>()<span class="keyword"> const </span>{<span class="keywordflow">return</span> 0-m_halfs.high;}
<a name="l00266"></a>00266 
<a name="l00267"></a>00267 <span class="keyword">private</span>:
<a name="l00268"></a>00268         <span class="keyword">union</span>
<a name="l00269"></a>00269         {
<a name="l00270"></a>00270 <span class="preprocessor">        #ifdef CRYPTOPP_NATIVE_DWORD_AVAILABLE</span>
<a name="l00271"></a><a class="code" href="class_d_word.html#f1503dcbfece6416389ad1ff69a0c10b">00271</a> <span class="preprocessor"></span>                dword <a class="code" href="class_d_word.html#f1503dcbfece6416389ad1ff69a0c10b">m_whole</a>;
<a name="l00272"></a>00272 <span class="preprocessor">        #endif</span>
<a name="l00273"></a>00273 <span class="preprocessor"></span>                <span class="keyword">struct</span>
<a name="l00274"></a>00274                 {
<a name="l00275"></a>00275 <span class="preprocessor">                #ifdef IS_LITTLE_ENDIAN</span>
<a name="l00276"></a><a class="code" href="class_d_word.html#be364d3c0509c62f464e3813e152502e">00276</a> <span class="preprocessor"></span>                        word <a class="code" href="class_d_word.html#be364d3c0509c62f464e3813e152502e">low</a>;
<a name="l00277"></a><a class="code" href="class_d_word.html#b961352c0156e8a803cc7f06fac36f4f">00277</a>                         word <a class="code" href="class_d_word.html#b961352c0156e8a803cc7f06fac36f4f">high</a>;
<a name="l00278"></a>00278 <span class="preprocessor">                #else</span>
<a name="l00279"></a>00279 <span class="preprocessor"></span>                        word high;
<a name="l00280"></a>00280                         word low;
<a name="l00281"></a>00281 <span class="preprocessor">                #endif</span>
<a name="l00282"></a>00282 <span class="preprocessor"></span>                } m_halfs;
<a name="l00283"></a>00283         };
<a name="l00284"></a>00284 };
<a name="l00285"></a>00285 
<a name="l00286"></a><a class="code" href="class_word.html">00286</a> <span class="keyword">class </span><a class="code" href="class_word.html">Word</a>
<a name="l00287"></a>00287 {
<a name="l00288"></a>00288 <span class="keyword">public</span>:
<a name="l00289"></a><a class="code" href="class_word.html#17baf7109d46beb48d5b469f3baedc48">00289</a>         <a class="code" href="class_word.html#17baf7109d46beb48d5b469f3baedc48">Word</a>() {}
<a name="l00290"></a>00290 
<a name="l00291"></a><a class="code" href="class_word.html#7755d2fa17ee18931eb5a8f763219867">00291</a>         <a class="code" href="class_word.html#17baf7109d46beb48d5b469f3baedc48">Word</a>(word value)
<a name="l00292"></a>00292         {
<a name="l00293"></a>00293                 m_whole = value;
<a name="l00294"></a>00294         }
<a name="l00295"></a>00295 
<a name="l00296"></a><a class="code" href="class_word.html#fa9303935900b3db97500b14d57655ff">00296</a>         <a class="code" href="class_word.html#17baf7109d46beb48d5b469f3baedc48">Word</a>(hword low, hword high)
<a name="l00297"></a>00297         {
<a name="l00298"></a>00298                 m_whole = low | (word(high) &lt;&lt; (WORD_BITS/2));
<a name="l00299"></a>00299         }
<a name="l00300"></a>00300 
<a name="l00301"></a><a class="code" href="class_word.html#e67733582b922d0737c28292b33ed83b">00301</a>         <span class="keyword">static</span> <a class="code" href="class_word.html">Word</a> <a class="code" href="class_word.html#e67733582b922d0737c28292b33ed83b">Multiply</a>(hword a, hword b)
<a name="l00302"></a>00302         {
<a name="l00303"></a>00303                 <a class="code" href="class_word.html">Word</a> r;
<a name="l00304"></a>00304                 r.<a class="code" href="class_word.html#100f37628da4e4eb81059906e14c2ac0">m_whole</a> = (word)a * b;
<a name="l00305"></a>00305                 <span class="keywordflow">return</span> r;
<a name="l00306"></a>00306         }
<a name="l00307"></a>00307 
<a name="l00308"></a><a class="code" href="class_word.html#95c8ed23e30aa0ee042b89d5f0aa179e">00308</a>         <a class="code" href="class_word.html">Word</a> <a class="code" href="class_word.html#95c8ed23e30aa0ee042b89d5f0aa179e">operator-</a>(<a class="code" href="class_word.html">Word</a> a)
<a name="l00309"></a>00309         {
<a name="l00310"></a>00310                 <a class="code" href="class_word.html">Word</a> r;
<a name="l00311"></a>00311                 r.<a class="code" href="class_word.html#100f37628da4e4eb81059906e14c2ac0">m_whole</a> = m_whole - a.<a class="code" href="class_word.html#100f37628da4e4eb81059906e14c2ac0">m_whole</a>;
<a name="l00312"></a>00312                 <span class="keywordflow">return</span> r;
<a name="l00313"></a>00313         }
<a name="l00314"></a>00314 
<a name="l00315"></a><a class="code" href="class_word.html#76b96e8ec4893b3d6631328cd5cf2795">00315</a>         <a class="code" href="class_word.html">Word</a> <a class="code" href="class_word.html#95c8ed23e30aa0ee042b89d5f0aa179e">operator-</a>(hword a)
<a name="l00316"></a>00316         {
<a name="l00317"></a>00317                 <a class="code" href="class_word.html">Word</a> r;
<a name="l00318"></a>00318                 r.<a class="code" href="class_word.html#100f37628da4e4eb81059906e14c2ac0">m_whole</a> = m_whole - a;
<a name="l00319"></a>00319                 <span class="keywordflow">return</span> r;
<a name="l00320"></a>00320         }
<a name="l00321"></a>00321 
<a name="l00322"></a>00322         <span class="comment">// returns quotient, which must fit in a word</span>
<a name="l00323"></a><a class="code" href="class_word.html#4afdaf0220c6c6c3dc118771dc102012">00323</a>         hword <a class="code" href="class_word.html#4afdaf0220c6c6c3dc118771dc102012">operator/</a>(hword divisor)
<a name="l00324"></a>00324         {
<a name="l00325"></a>00325                 <span class="keywordflow">return</span> hword(m_whole / divisor);
<a name="l00326"></a>00326         }
<a name="l00327"></a>00327 
<a name="l00328"></a><a class="code" href="class_word.html#5f7b66510791ef34ba1d36407f622efb">00328</a>         <span class="keywordtype">bool</span> <a class="code" href="class_word.html#5f7b66510791ef34ba1d36407f622efb">operator!</a>()<span class="keyword"> const</span>
<a name="l00329"></a>00329 <span class="keyword">        </span>{
<a name="l00330"></a>00330                 <span class="keywordflow">return</span> !m_whole;
<a name="l00331"></a>00331         }
<a name="l00332"></a>00332 
<a name="l00333"></a><a class="code" href="class_word.html#10078f81e29678249c1d81791ed096ce">00333</a>         word <a class="code" href="class_word.html#10078f81e29678249c1d81791ed096ce">GetWhole</a>()<span class="keyword"> const </span>{<span class="keywordflow">return</span> m_whole;}
<a name="l00334"></a><a class="code" href="class_word.html#524c2ada082266b8437093a2d221df96">00334</a>         hword <a class="code" href="class_word.html#524c2ada082266b8437093a2d221df96">GetLowHalf</a>()<span class="keyword"> const </span>{<span class="keywordflow">return</span> hword(m_whole);}
<a name="l00335"></a><a class="code" href="class_word.html#e817e13c45b9199fbb8125d99ce30350">00335</a>         hword <a class="code" href="class_word.html#e817e13c45b9199fbb8125d99ce30350">GetHighHalf</a>()<span class="keyword"> const </span>{<span class="keywordflow">return</span> hword(m_whole&gt;&gt;(WORD_BITS/2));}
<a name="l00336"></a><a class="code" href="class_word.html#08ef4c68a16133075ba1e98a65666257">00336</a>         hword <a class="code" href="class_word.html#08ef4c68a16133075ba1e98a65666257">GetHighHalfAsBorrow</a>()<span class="keyword"> const </span>{<span class="keywordflow">return</span> 0-hword(m_whole&gt;&gt;(WORD_BITS/2));}
<a name="l00337"></a>00337         
<a name="l00338"></a>00338 <span class="keyword">private</span>:
<a name="l00339"></a>00339         word m_whole;
<a name="l00340"></a>00340 };
<a name="l00341"></a>00341 
<a name="l00342"></a>00342 <span class="comment">// do a 3 word by 2 word divide, returns quotient and leaves remainder in A</span>
<a name="l00343"></a>00343 <span class="keyword">template</span> &lt;<span class="keyword">class</span> S, <span class="keyword">class</span> D&gt;
<a name="l00344"></a>00344 S DivideThreeWordsByTwo(S *A, S B0, S B1, D *dummy=NULL)
<a name="l00345"></a>00345 {
<a name="l00346"></a>00346         <span class="comment">// assert {A[2],A[1]} &lt; {B1,B0}, so quotient can fit in a S</span>
<a name="l00347"></a>00347         assert(A[2] &lt; B1 || (A[2]==B1 &amp;&amp; A[1] &lt; B0));
<a name="l00348"></a>00348 
<a name="l00349"></a>00349         <span class="comment">// estimate the quotient: do a 2 S by 1 S divide</span>
<a name="l00350"></a>00350         S Q;
<a name="l00351"></a>00351         <span class="keywordflow">if</span> (S(B1+1) == 0)
<a name="l00352"></a>00352                 Q = A[2];
<a name="l00353"></a>00353         <span class="keywordflow">else</span>
<a name="l00354"></a>00354                 Q = D(A[1], A[2]) / S(B1+1);
<a name="l00355"></a>00355 
<a name="l00356"></a>00356         <span class="comment">// now subtract Q*B from A</span>
<a name="l00357"></a>00357         D p = D::Multiply(B0, Q);
<a name="l00358"></a>00358         D u = (D) A[0] - p.GetLowHalf();
<a name="l00359"></a>00359         A[0] = u.GetLowHalf();
<a name="l00360"></a>00360         u = (D) A[1] - p.GetHighHalf() - u.GetHighHalfAsBorrow() - D::Multiply(B1, Q);
<a name="l00361"></a>00361         A[1] = u.GetLowHalf();
<a name="l00362"></a>00362         A[2] += u.GetHighHalf();
<a name="l00363"></a>00363