zinflate_8cpp-source.html

Crypto++是一个非常强大的密码学库,主要是功能全

00292 {
00293         <span class="keywordflow">if</span> (!blocking)
00294                 <span class="keywordflow">throw</span> BlockingInputOnly(<span class="stringliteral">"Inflator"</span>);
00295 
00296         <span class="keywordflow">if</span> (hardFlush)
00297                 ProcessInput(<span class="keyword">true</span>);
00298         FlushOutput();
00299 
00300         <span class="keywordflow">return</span> <span class="keyword">false</span>;
00301 }
00302 
00303 <span class="keywordtype">void</span> Inflator::ProcessInput(<span class="keywordtype">bool</span> flush)
00304 {
00305         <span class="keywordflow">while</span> (<span class="keyword">true</span>)
00306         {
00307                 <span class="keywordflow">if</span> (m_inQueue.<a class="code" href="class_byte_queue.html#_d_e_r_set_encodera16">IsEmpty</a>())
00308                         <span class="keywordflow">return</span>;
00309 
00310                 <span class="keywordflow">switch</span> (m_state)
00311                 {
00312                 <span class="keywordflow">case</span> PRE_STREAM:
00313                         <span class="keywordflow">if</span> (!flush &amp;&amp; m_inQueue.<a class="code" href="class_byte_queue.html#_d_e_r_set_encodera15">CurrentSize</a>() &lt; MaxPrestreamHeaderSize())
00314                                 <span class="keywordflow">return</span>;
00315                         ProcessPrestreamHeader();
00316                         m_state = WAIT_HEADER;
00317                         m_maxDistance = 0;
00318                         m_current = 0;
00319                         m_lastFlush = 0;
00320                         m_window.<a class="code" href="class_sec_block.html#_sec_block_with_hinta19">New</a>(1 &lt;&lt; GetLog2WindowSize());
00321                         <span class="keywordflow">break</span>;
00322                 <span class="keywordflow">case</span> WAIT_HEADER:
00323                         {
00324                         <span class="comment">// maximum number of bytes before actual compressed data starts</span>
00325                         <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> MAX_HEADER_SIZE = BitsToBytes(3+5+5+4+19*7+286*15+19*15);
00326                         <span class="keywordflow">if</span> (m_inQueue.<a class="code" href="class_byte_queue.html#_d_e_r_set_encodera15">CurrentSize</a>() &lt; (flush ? 1 : MAX_HEADER_SIZE))
00327                                 <span class="keywordflow">return</span>;
00328                         DecodeHeader();
00329                         <span class="keywordflow">break</span>;
00330                         }
00331                 <span class="keywordflow">case</span> DECODING_BODY:
00332                         <span class="keywordflow">if</span> (!DecodeBody())
00333                                 <span class="keywordflow">return</span>;
00334                         <span class="keywordflow">break</span>;
00335                 <span class="keywordflow">case</span> POST_STREAM:
00336                         <span class="keywordflow">if</span> (!flush &amp;&amp; m_inQueue.<a class="code" href="class_byte_queue.html#_d_e_r_set_encodera15">CurrentSize</a>() &lt; MaxPoststreamTailSize())
00337                                 <span class="keywordflow">return</span>;
00338                         ProcessPoststreamTail();
00339                         m_state = m_repeat ? PRE_STREAM : AFTER_END;
00340                         Output(0, NULL, 0, GetAutoSignalPropagation(), <span class="keyword">true</span>);   <span class="comment">// TODO: non-blocking</span>
00341                         <span class="keywordflow">break</span>;
00342                 <span class="keywordflow">case</span> AFTER_END:
00343                         m_inQueue.<a class="code" href="class_buffered_transformation.html#_zlib_decompressorz7_10">TransferTo</a>(*<a class="code" href="class_filter.html#_zlib_decompressora8">AttachedTransformation</a>());
00344                         <span class="keywordflow">return</span>;
00345                 }
00346         }
00347 }
00348 
00349 <span class="keywordtype">void</span> Inflator::DecodeHeader()
00350 {
00351         <span class="keywordflow">if</span> (!m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera4">FillBuffer</a>(3))
00352                 <span class="keywordflow">throw</span> UnexpectedEndErr();
00353         m_eof = m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(1) != 0;
00354         m_blockType = (byte)m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(2);
00355         <span class="keywordflow">switch</span> (m_blockType)
00356         {
00357         <span class="keywordflow">case</span> 0: <span class="comment">// stored</span>
00358                 {
00359                 m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera6">SkipBits</a>(m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera2">BitsBuffered</a>() % 8);
00360                 <span class="keywordflow">if</span> (!m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera4">FillBuffer</a>(32))
00361                         <span class="keywordflow">throw</span> UnexpectedEndErr();
00362                 m_storedLen = (word16)m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(16);
00363                 word16 nlen = (word16)m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(16);
00364                 <span class="keywordflow">if</span> (nlen != (word16)~m_storedLen)
00365                         <span class="keywordflow">throw</span> BadBlockErr();
00366                 <span class="keywordflow">break</span>;
00367                 }
00368         <span class="keywordflow">case</span> 1: <span class="comment">// fixed codes</span>
00369                 <span class="keywordflow">if</span> (!m_decodersInitializedWithFixedCodes)
00370                 {
00371                         <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> codeLengths[288];
00372                         std::fill(codeLengths + 0, codeLengths + 144, 8);
00373                         std::fill(codeLengths + 144, codeLengths + 256, 9);
00374                         std::fill(codeLengths + 256, codeLengths + 280, 7);
00375                         std::fill(codeLengths + 280, codeLengths + 288, 8);
00376                         m_literalDecoder.<a class="code" href="class_huffman_decoder.html#_huffman_decodera2">Initialize</a>(codeLengths, 288);
00377                         std::fill(codeLengths + 0, codeLengths + 32, 5);
00378                         m_distanceDecoder.<a class="code" href="class_huffman_decoder.html#_huffman_decodera2">Initialize</a>(codeLengths, 32);
00379                         m_decodersInitializedWithFixedCodes = <span class="keyword">true</span>;
00380                 }
00381                 m_nextDecode = LITERAL;
00382                 <span class="keywordflow">break</span>;
00383         <span class="keywordflow">case</span> 2: <span class="comment">// dynamic codes</span>
00384                 {
00385                 m_decodersInitializedWithFixedCodes = <span class="keyword">false</span>;
00386                 <span class="keywordflow">if</span> (!m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera4">FillBuffer</a>(5+5+4))
00387                         <span class="keywordflow">throw</span> UnexpectedEndErr();
00388                 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> hlit = m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(5);
00389                 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> hdist = m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(5);
00390                 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> hclen = m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(4);
00391 
00392                 FixedSizeSecBlock&lt;unsigned int, 286+32&gt; codeLengths;
00393                 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i;
00394                 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> border[] = {    <span class="comment">// Order of the bit length code lengths</span>
00395                         16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
00396                 std::fill(codeLengths.<a class="code" href="class_sec_block.html#_sec_block_with_hinta7">begin</a>(), codeLengths+19, 0);
00397                 <span class="keywordflow">for</span> (i=0; i&lt;hclen+4; i++)
00398                         codeLengths[border[i]] = m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(3);
00399 
00400                 <span class="keywordflow">try</span>
00401                 {
00402                         <a class="code" href="class_huffman_decoder.html">HuffmanDecoder</a> codeLengthDecoder(codeLengths, 19);
00403                         <span class="keywordflow">for</span> (i = 0; i &lt; hlit+257+hdist+1; )
00404                         {
00405                                 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> k, count, repeater;
00406                                 <span class="keywordtype">bool</span> result = codeLengthDecoder.<a class="code" href="class_huffman_decoder.html#_huffman_decodera3">Decode</a>(m_reader, k);
00407                                 <span class="keywordflow">if</span> (!result)
00408                                         <span class="keywordflow">throw</span> UnexpectedEndErr();
00409                                 <span class="keywordflow">if</span> (k &lt;= 15)
00410                                 {
00411                                         count = 1;
00412                                         repeater = k;
00413                                 }
00414                                 <span class="keywordflow">else</span> <span class="keywordflow">switch</span> (k)
00415                                 {
00416                                 <span class="keywordflow">case</span> 16:
00417                                         <span class="keywordflow">if</span> (!m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera4">FillBuffer</a>(2))
00418                                                 <span class="keywordflow">throw</span> UnexpectedEndErr();
00419                                         count = 3 + m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(2);
00420                                         <span class="keywordflow">if</span> (i == 0)
00421                                                 <span class="keywordflow">throw</span> BadBlockErr();
00422                                         repeater = codeLengths[i-1];
00423                                         <span class="keywordflow">break</span>;
00424                                 <span class="keywordflow">case</span> 17:
00425                                         <span class="keywordflow">if</span> (!m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera4">FillBuffer</a>(3))
00426                                                 <span class="keywordflow">throw</span> UnexpectedEndErr();
00427                                         count = 3 + m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(3);
00428                                         repeater = 0;
00429                                         <span class="keywordflow">break</span>;
00430                                 <span class="keywordflow">case</span> 18:
00431                                         <span class="keywordflow">if</span> (!m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera4">FillBuffer</a>(7))
00432                                                 <span class="keywordflow">throw</span> UnexpectedEndErr();
00433                                         count = 11 + m_reader.<a class="code" href="class_low_first_bit_reader.html#_low_first_bit_readera7">GetBits</a>(7);
00434                                         repeater = 0;
00435                                         <span class="keywordflow">break</span>;
00436                                 }
00437                                 <span class="keywordflow">if</span> (i + count &gt; hlit+257+hdist+1)
00438                                         <span class="keywordflow">throw</span> BadBlockErr();
00439                                 std::fill(codeLengths + i, codeLengths + i + count, repeater);
00440                                 i += count;