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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"><title>Crypto++: iterhash.cpp Source File</title><link href="doxygen.css" rel="stylesheet" type="text/css"><link href="tabs.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.5.2 --><div class="tabs"> <ul> <li><a href="index.html"><span>Main Page</span></a></li> <li><a href="namespaces.html"><span>Namespaces</span></a></li> <li><a href="classes.html"><span>Classes</span></a></li> <li class="current"><a href="files.html"><span>Files</span></a></li> </ul></div><div class="tabs"> <ul> <li><a href="files.html"><span>File List</span></a></li> <li><a href="globals.html"><span>File Members</span></a></li> </ul></div><h1>iterhash.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// iterhash.cpp - written and placed in the public domain by Wei Dai</span><a name="l00002"></a>00002 <a name="l00003"></a>00003 <span class="preprocessor">#include "pch.h"</span><a name="l00004"></a>00004 <a name="l00005"></a>00005 <span class="comment">// prevent Sun's CC compiler from including this file automatically</span><a name="l00006"></a>00006 <span class="preprocessor">#if !defined(__SUNPRO_CC) || defined(CRYPTOPP_MANUALLY_INSTANTIATE_TEMPLATES)</span><a name="l00007"></a>00007 <span class="preprocessor"></span><a name="l00008"></a>00008 <span class="preprocessor">#include "iterhash.h"</span><a name="l00009"></a>00009 <span class="preprocessor">#include "misc.h"</span><a name="l00010"></a>00010 <a name="l00011"></a>00011 NAMESPACE_BEGIN(CryptoPP)<a name="l00012"></a>00012 <a name="l00013"></a><a class="code" href="class_iterated_hash_base.html#3202914349a18f79facb605d75f0d10c">00013</a> template <class T, class BASE> <span class="keywordtype">void</span> <a class="code" href="class_iterated_hash_base.html" title="_">IteratedHashBase</a><T, BASE>::Update(const byte *input, <span class="keywordtype">size_t</span> len)<a name="l00014"></a>00014 {<a name="l00015"></a>00015 HashWordType oldCountLo = m_countLo, oldCountHi = m_countHi;<a name="l00016"></a>00016 <span class="keywordflow">if</span> ((m_countLo = oldCountLo + HashWordType(len)) < oldCountLo)<a name="l00017"></a>00017 m_countHi++; <span class="comment">// carry from low to high</span><a name="l00018"></a>00018 m_countHi += (HashWordType)SafeRightShift<8*<span class="keyword">sizeof</span>(HashWordType)>(len);<a name="l00019"></a>00019 <span class="keywordflow">if</span> (m_countHi < oldCountHi || SafeRightShift<2*8*<span class="keyword">sizeof</span>(HashWordType)>(len) != 0)<a name="l00020"></a>00020 <span class="keywordflow">throw</span> <a class="code" href="class_hash_input_too_long.html" title="exception thrown when trying to hash more data than is allowed by a hash function...">HashInputTooLong</a>(this->AlgorithmName());<a name="l00021"></a>00021 <a name="l00022"></a>00022 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> blockSize = this->BlockSize();<a name="l00023"></a>00023 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> num = ModPowerOf2(oldCountLo, blockSize);<a name="l00024"></a>00024 T* dataBuf = this->DataBuf();<a name="l00025"></a>00025 byte* data = (byte *)dataBuf;<a name="l00026"></a>00026 <a name="l00027"></a>00027 <span class="keywordflow">if</span> (num != 0) <span class="comment">// process left over data</span><a name="l00028"></a>00028 {<a name="l00029"></a>00029 <span class="keywordflow">if</span> ((num+len) >= blockSize)<a name="l00030"></a>00030 {<a name="l00031"></a>00031 memcpy(data+num, input, blockSize-num);<a name="l00032"></a>00032 HashBlock(dataBuf);<a name="l00033"></a>00033 input += (blockSize-num);<a name="l00034"></a>00034 len-=(blockSize - num);<a name="l00035"></a>00035 num=0;<a name="l00036"></a>00036 <span class="comment">// drop through and do the rest</span><a name="l00037"></a>00037 }<a name="l00038"></a>00038 <span class="keywordflow">else</span><a name="l00039"></a>00039 {<a name="l00040"></a>00040 memcpy(data+num, input, len);<a name="l00041"></a>00041 <span class="keywordflow">return</span>;<a name="l00042"></a>00042 }<a name="l00043"></a>00043 }<a name="l00044"></a>00044 <a name="l00045"></a>00045 <span class="comment">// now process the input data in blocks of blockSize bytes and save the leftovers to m_data</span><a name="l00046"></a>00046 <span class="keywordflow">if</span> (len >= blockSize)<a name="l00047"></a>00047 {<a name="l00048"></a>00048 <span class="keywordflow">if</span> (input == data)<a name="l00049"></a>00049 {<a name="l00050"></a>00050 assert(len == blockSize);<a name="l00051"></a>00051 HashBlock(dataBuf);<a name="l00052"></a>00052 <span class="keywordflow">return</span>;<a name="l00053"></a>00053 }<a name="l00054"></a>00054 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (IsAligned<T>(input))<a name="l00055"></a>00055 {<a name="l00056"></a>00056 <span class="keywordtype">size_t</span> leftOver = HashMultipleBlocks((T *)input, len);<a name="l00057"></a>00057 input += (len - leftOver);<a name="l00058"></a>00058 len = leftOver;<a name="l00059"></a>00059 }<a name="l00060"></a>00060 <span class="keywordflow">else</span><a name="l00061"></a>00061 <span class="keywordflow">do</span><a name="l00062"></a>00062 { <span class="comment">// copy input first if it's not aligned correctly</span><a name="l00063"></a>00063 memcpy(data, input, blockSize);<a name="l00064"></a>00064 HashBlock(dataBuf);<a name="l00065"></a>00065 input+=blockSize;<a name="l00066"></a>00066 len-=blockSize;<a name="l00067"></a>00067 } <span class="keywordflow">while</span> (len >= blockSize);<a name="l00068"></a>00068 }⌨️ 快捷键说明
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