zdeflate_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="l00360"></a>00360 }
<a name="l00361"></a>00361 
<a name="l00362"></a><a class="code" href="class_deflator.html#f39e464efb6676829a3b9f3ea0c5f19c">00362</a> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> <a class="code" href="class_deflator.html#f39e464efb6676829a3b9f3ea0c5f19c">Deflator::LongestMatch</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> &amp;bestMatch)<span class="keyword"> const</span>
<a name="l00363"></a>00363 <span class="keyword"></span>{
<a name="l00364"></a>00364         assert(<a class="code" href="class_deflator.html#2767a520eafdf665867a5e7d1de058d7">m_previousLength</a> &lt; <a class="code" href="class_deflator.html#5d1d2b1a7c83fa2b2ebb2adeb646d4ba76770cb68144334520c092799bbb212f">MAX_MATCH</a>);
<a name="l00365"></a>00365 
<a name="l00366"></a>00366         bestMatch = 0;
<a name="l00367"></a>00367         <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> bestLength = STDMAX(<a class="code" href="class_deflator.html#2767a520eafdf665867a5e7d1de058d7">m_previousLength</a>, (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span>)<a class="code" href="class_deflator.html#5d1d2b1a7c83fa2b2ebb2adeb646d4ba627d91626b89f0f830d8aaab84f7b5b0">MIN_MATCH</a>-1);
<a name="l00368"></a>00368         <span class="keywordflow">if</span> (<a class="code" href="class_deflator.html#e7b072afd802843284402d648e64412d">m_lookahead</a> &lt;= bestLength)
<a name="l00369"></a>00369                 <span class="keywordflow">return</span> 0;
<a name="l00370"></a>00370 
<a name="l00371"></a>00371         <span class="keyword">const</span> byte *scan = <a class="code" href="class_deflator.html#3d899c14cdac6972d8128c32befe3c1a">m_byteBuffer</a> + <a class="code" href="class_deflator.html#42a99f00a21bdf38d9daa15dd2ec8a5d">m_stringStart</a>, *scanEnd = scan + STDMIN((<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span>)<a class="code" href="class_deflator.html#5d1d2b1a7c83fa2b2ebb2adeb646d4ba76770cb68144334520c092799bbb212f">MAX_MATCH</a>, <a class="code" href="class_deflator.html#e7b072afd802843284402d648e64412d">m_lookahead</a>);
<a name="l00372"></a>00372         <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> limit = m_stringStart &gt; (<a class="code" href="class_deflator.html#cbb3318729a2a96a2d957c36c7dcd158">DSIZE</a>-MAX_MATCH) ? m_stringStart - (<a class="code" href="class_deflator.html#cbb3318729a2a96a2d957c36c7dcd158">DSIZE</a>-MAX_MATCH) : 0;
<a name="l00373"></a>00373         <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> current = <a class="code" href="class_deflator.html#e72ff240bd264f77f2099c71966fdbf5">m_head</a>[<a class="code" href="class_deflator.html#44c260b1a4ac0fa54e5e80c4df0ff121">ComputeHash</a>(scan)];
<a name="l00374"></a>00374 
<a name="l00375"></a>00375         <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> chainLength = <a class="code" href="class_deflator.html#29f0111d74dfdcf365f84ff070714504">MAX_CHAIN_LENGTH</a>;
<a name="l00376"></a>00376         <span class="keywordflow">if</span> (<a class="code" href="class_deflator.html#2767a520eafdf665867a5e7d1de058d7">m_previousLength</a> &gt;= <a class="code" href="class_deflator.html#d5abb84cfaeaa82079f4c98930ba69ce">GOOD_MATCH</a>)
<a name="l00377"></a>00377                 chainLength &gt;&gt;= 2;
<a name="l00378"></a>00378 
<a name="l00379"></a>00379         <span class="keywordflow">while</span> (current &gt; limit &amp;&amp; --chainLength &gt; 0)
<a name="l00380"></a>00380         {
<a name="l00381"></a>00381                 <span class="keyword">const</span> byte *match = <a class="code" href="class_deflator.html#3d899c14cdac6972d8128c32befe3c1a">m_byteBuffer</a> + current;
<a name="l00382"></a>00382                 assert(scan + bestLength &lt; <a class="code" href="class_deflator.html#3d899c14cdac6972d8128c32befe3c1a">m_byteBuffer</a> + m_stringStart + <a class="code" href="class_deflator.html#e7b072afd802843284402d648e64412d">m_lookahead</a>);
<a name="l00383"></a>00383                 <span class="keywordflow">if</span> (scan[bestLength-1] == match[bestLength-1] &amp;&amp; scan[bestLength] == match[bestLength] &amp;&amp; scan[0] == match[0] &amp;&amp; scan[1] == match[1])
<a name="l00384"></a>00384                 {
<a name="l00385"></a>00385                         assert(scan[2] == match[2]);
<a name="l00386"></a>00386                         <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> len = (<span class="keywordtype">unsigned</span> int)(
<a name="l00387"></a>00387 #<span class="keywordflow">if</span> defined(_STDEXT_BEGIN) &amp;&amp; !(defined(_MSC_VER) &amp;&amp; _MSC_VER &lt; 1400)
<a name="l00388"></a>00388                                 stdext::unchecked_mismatch
<a name="l00389"></a>00389 #<span class="keywordflow">else</span>
<a name="l00390"></a>00390                                 std::mismatch
<a name="l00391"></a>00391 #endif
<a name="l00392"></a>00392                                 (scan+3, scanEnd, match+3).first - scan);
<a name="l00393"></a>00393                         assert(len != bestLength);
<a name="l00394"></a>00394                         <span class="keywordflow">if</span> (len &gt; bestLength)
<a name="l00395"></a>00395                         {
<a name="l00396"></a>00396                                 bestLength = len;
<a name="l00397"></a>00397                                 bestMatch = current;
<a name="l00398"></a>00398                                 <span class="keywordflow">if</span> (len == (scanEnd - scan))
<a name="l00399"></a>00399                                         <span class="keywordflow">break</span>;
<a name="l00400"></a>00400                         }
<a name="l00401"></a>00401                 }
<a name="l00402"></a>00402                 current = <a class="code" href="class_deflator.html#ad7bfe8bebc06108c48f08d96e1f88f2">m_prev</a>[current &amp; <a class="code" href="class_deflator.html#bc8dd3d3c28d9b188dd1c19510294a0b">DMASK</a>];
<a name="l00403"></a>00403         }
<a name="l00404"></a>00404         <span class="keywordflow">return</span> (bestMatch &gt; 0) ? bestLength : 0;
<a name="l00405"></a>00405 }
<a name="l00406"></a>00406 
<a name="l00407"></a><a class="code" href="class_deflator.html#ded37de66827ee6def1d3bb5a7c19315">00407</a> <span class="keyword">inline</span> <span class="keywordtype">void</span> <a class="code" href="class_deflator.html#ded37de66827ee6def1d3bb5a7c19315">Deflator::InsertString</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> start)
<a name="l00408"></a>00408 {
<a name="l00409"></a>00409         <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> hash = <a class="code" href="class_deflator.html#44c260b1a4ac0fa54e5e80c4df0ff121">ComputeHash</a>(<a class="code" href="class_deflator.html#3d899c14cdac6972d8128c32befe3c1a">m_byteBuffer</a> + start);
<a name="l00410"></a>00410         <a class="code" href="class_deflator.html#ad7bfe8bebc06108c48f08d96e1f88f2">m_prev</a>[start &amp; <a class="code" href="class_deflator.html#bc8dd3d3c28d9b188dd1c19510294a0b">DMASK</a>] = <a class="code" href="class_deflator.html#e72ff240bd264f77f2099c71966fdbf5">m_head</a>[hash];
<a name="l00411"></a>00411         <a class="code" href="class_deflator.html#e72ff240bd264f77f2099c71966fdbf5">m_head</a>[hash] = start;
<a name="l00412"></a>00412 }
<a name="l00413"></a>00413 
<a name="l00414"></a><a class="code" href="class_deflator.html#3002c3031d2432fa3d201caeec1a7f4b">00414</a> <span class="keywordtype">void</span> <a class="code" href="class_deflator.html#3002c3031d2432fa3d201caeec1a7f4b">Deflator::ProcessBuffer</a>()
<a name="l00415"></a>00415 {
<a name="l00416"></a>00416         <span class="keywordflow">if</span> (!<a class="code" href="class_deflator.html#061a05e91d67cdf0d326ccf870cf7ef1">m_headerWritten</a>)
<a name="l00417"></a>00417         {
<a name="l00418"></a>00418                 <a class="code" href="class_deflator.html#4d36fef18ebdbd5827fcb41ab4d8203a">WritePrestreamHeader</a>();
<a name="l00419"></a>00419                 <a class="code" href="class_deflator.html#061a05e91d67cdf0d326ccf870cf7ef1">m_headerWritten</a> = <span class="keyword">true</span>;
<a name="l00420"></a>00420         }
<a name="l00421"></a>00421 
<a name="l00422"></a>00422         <span class="keywordflow">if</span> (<a class="code" href="class_deflator.html#028cf53ff50d3bdd7ce3b8823fb01036">m_deflateLevel</a> == 0)
<a name="l00423"></a>00423         {
<a name="l00424"></a>00424                 <a class="code" href="class_deflator.html#42a99f00a21bdf38d9daa15dd2ec8a5d">m_stringStart</a> += <a class="code" href="class_deflator.html#e7b072afd802843284402d648e64412d">m_lookahead</a>;
<a name="l00425"></a>00425                 <a class="code" href="class_deflator.html#e7b072afd802843284402d648e64412d">m_lookahead</a> = 0;
<a name="l00426"></a>00426                 <a class="code" href="class_deflator.html#7bbef1e0fe539c42509a7bebefc7cb1e">m_blockLength</a> = <a class="code" href="class_deflator.html#42a99f00a21bdf38d9daa15dd2ec8a5d">m_stringStart</a> - <a class="code" href="class_deflator.html#f664ac5ab288e3099324ef2ad051719e">m_blockStart</a>;
<a name="l00427"></a>00427                 <a class="code" href="class_deflator.html#5241d030b8b368014b1c04281bf87fc3">m_matchAvailable</a> = <span class="keyword">false</span>;
<a name="l00428"></a>00428                 <span class="keywordflow">return</span>;
<a name="l00429"></a>00429         }
<a name="l00430"></a>00430 
<a name="l00431"></a>00431         <span class="keywordflow">while</span> (<a class="code" href="class_deflator.html#e7b072afd802843284402d648e64412d">m_lookahead</a> &gt; <a class="code" href="class_deflator.html#3646115b10f173efb62402985657bb05">m_minLookahead</a>)
<a name="l00432"></a>00432         {
<a name="l00433"></a>00433                 <span class="keywordflow">while</span> (<a class="code" href="class_deflator.html#8e20cb9e5a29755b016386778221c825">m_dictionaryEnd</a> &lt; <a class="code" href="class_deflator.html#42a99f00a21bdf38d9daa15dd2ec8a5d">m_stringStart</a> &amp;&amp; <a class="code" href="class_deflator.html#8e20cb9e5a29755b016386778221c825">m_dictionaryEnd</a>+3 &lt;= <a class="code" href="class_deflator.html#42a99f00a21bdf38d9daa15dd2ec8a5d">m_stringStart</a>+<a class="code" href="class_deflator.html#e7b072afd802843284402d648e64412d">m_lookahead</a>)
<a name="l00434"></a>00434                         <a class="code" href="class_deflator.html#ded37de66827ee6def1d3bb5a7c19315">InsertString</a>(<a class="code" href="class_deflator.html#8e20cb9e5a29755b016386778221c825">m_dictionaryEnd</a>++);
<a name="l00435"></a>00435 
<a name="l00436"></a>00436                 <span class="keywordflow">if</span> (<a class="code" href="class_deflator.html#5241d030b8b368014b1c04281bf87fc3">m_matchAvailable</a>)
<a name="l00437"></a>00437                 {
<a name="l00438"></a>00438                         <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> matchPosition, matchLength;
<a name="l00439"></a>00439                         <span class="keywordtype">bool</span> usePreviousMatch;
<a name="l00440"></a>00440                         <span class="keywordflow">if</span> (<a class="code" href="class_deflator.html#2767a520eafdf665867a5e7d1de058d7">m_previousLength</a> &gt;= <a class="code" href="class_deflator.html#821630c70545472963ac78bda4b46ac1">MAX_LAZYLENGTH</a>)
<a name="l00441"></a>00441                                 usePreviousMatch = <span class="keyword">true</span>;
<a name="l00442"></a>00442                         <span class="keywordflow">else</span>
<a name="l00443"></a>00443                         {
<a name="l00444"></a>00444                                 matchLength = <a class="code" href="class_deflator.html#f39e464efb6676829a3b9f3ea0c5f19c">LongestMatch</a>(matchPosition);
<a name="l00445"></a>00445                                 usePreviousMatch = (matchLength == 0);
<a name="l00446"></a>00446                         }
<a name="l00447"></a>00447                         <span class="keywordflow">if</span> (usePreviousMatch)
<a name="l00448"></a>00448                         {
<a name="l00449"></a>00449                                 <a class="code" href="class_deflator.html#5a5cb6258e2cfa731e47dfe33e2f9e4d">MatchFound</a>(<a class="code" href="class_deflator.html#42a99f00a21bdf38d9daa15dd2ec8a5d">m_stringStart</a>-1-<a class="code" href="class_deflator.html#f7bedc29fcbbdf6b8bf3aa8e06a3945a">m_previousMatch</a>, <a class="code" href="class_deflator.html#2767a520eafdf665867a5e7d1de058d7">m_previousLength</a>);
<a name="l00450"></a>00450                                 <a class="code" href="class_deflator.html#42a99f00a21bdf38d9daa15dd2ec8a5d">m_stringStart</a> += <a class="code" href="class_deflator.html#2767a520eafdf665867a5e7d1de058d7">m_previousLength</a>-1;
<a name="l00451"></a>00451                                 <a class="code" href="class_deflator.html#e7b072afd802843284402d648e64412d">m_lookahead</a> -= <a class="code" href="class_deflator.html#2767a520eafdf665867a5e7d1de058d7"