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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++: polynomi.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>polynomi.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// polynomi.cpp - written and placed in the public domain by Wei Dai</span><a name="l00002"></a>00002 <a name="l00003"></a>00003 <span class="comment">// Part of the code for polynomial evaluation and interpolation</span><a name="l00004"></a>00004 <span class="comment">// originally came from Hal Finney's public domain secsplit.c.</span><a name="l00005"></a>00005 <a name="l00006"></a>00006 <span class="preprocessor">#include "pch.h"</span><a name="l00007"></a>00007 <span class="preprocessor">#include "<a class="code" href="polynomi_8h.html">polynomi.h</a>"</span><a name="l00008"></a>00008 <span class="preprocessor">#include "secblock.h"</span><a name="l00009"></a>00009 <a name="l00010"></a>00010 <span class="preprocessor">#include <sstream></span><a name="l00011"></a>00011 <span class="preprocessor">#include <iostream></span><a name="l00012"></a>00012 <a name="l00013"></a>00013 NAMESPACE_BEGIN(CryptoPP)<a name="l00014"></a>00014 <a name="l00015"></a>00015 template <class T><a name="l00016"></a><a class="code" href="class_polynomial_over.html#3a895100d291eba0fba02f50b57d1d44">00016</a> <span class="keywordtype">void</span> <a class="code" href="class_polynomial_over.html" title="represents single-variable polynomials over arbitrary rings">PolynomialOver</a><T>::Randomize(<a class="code" href="class_random_number_generator.html" title="interface for random number generators">RandomNumberGenerator</a> &rng, const <a class="code" href="class_polynomial_over_1_1_randomization_parameter.html" title="specify the distribution for randomization functions">RandomizationParameter</a> &parameter, const Ring &ring)<a name="l00017"></a>00017 {<a name="l00018"></a>00018 m_coefficients.resize(parameter.m_coefficientCount);<a name="l00019"></a>00019 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i=0; i<m_coefficients.size(); ++i)<a name="l00020"></a>00020 m_coefficients[i] = ring.RandomElement(rng, parameter.m_coefficientParameter);<a name="l00021"></a>00021 }<a name="l00022"></a>00022 <a name="l00023"></a>00023 <span class="keyword">template</span> <<span class="keyword">class</span> T><a name="l00024"></a>00024 <span class="keywordtype">void</span> <a class="code" href="class_polynomial_over.html" title="represents single-variable polynomials over arbitrary rings">PolynomialOver<T>::FromStr</a>(<span class="keyword">const</span> <span class="keywordtype">char</span> *str, <span class="keyword">const</span> Ring &ring)<a name="l00025"></a>00025 {<a name="l00026"></a>00026 std::istringstream in((<span class="keywordtype">char</span> *)str);<a name="l00027"></a>00027 <span class="keywordtype">bool</span> positive = <span class="keyword">true</span>;<a name="l00028"></a>00028 <a class="code" href="class_polynomial_over.html#2eb91afba2d1f0c11f78f5825ecd5408">CoefficientType</a> coef;<a name="l00029"></a>00029 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> power;<a name="l00030"></a>00030 <a name="l00031"></a>00031 <span class="keywordflow">while</span> (in)<a name="l00032"></a>00032 {<a name="l00033"></a>00033 std::ws(in);<a name="l00034"></a>00034 <span class="keywordflow">if</span> (in.peek() == <span class="charliteral">'x'</span>)<a name="l00035"></a>00035 coef = ring.MultiplicativeIdentity();<a name="l00036"></a>00036 <span class="keywordflow">else</span><a name="l00037"></a>00037 in >> coef;<a name="l00038"></a>00038 <a name="l00039"></a>00039 std::ws(in);<a name="l00040"></a>00040 <span class="keywordflow">if</span> (in.peek() == <span class="charliteral">'x'</span>)<a name="l00041"></a>00041 {<a name="l00042"></a>00042 in.get();<a name="l00043"></a>00043 std::ws(in);<a name="l00044"></a>00044 <span class="keywordflow">if</span> (in.peek() == <span class="charliteral">'^'</span>)<a name="l00045"></a>00045 {<a name="l00046"></a>00046 in.get();<a name="l00047"></a>00047 in >> power;<a name="l00048"></a>00048 }<a name="l00049"></a>00049 <span class="keywordflow">else</span><a name="l00050"></a>00050 power = 1;<a name="l00051"></a>00051 }<a name="l00052"></a>00052 <span class="keywordflow">else</span><a name="l00053"></a>00053 power = 0;<a name="l00054"></a>00054 <a name="l00055"></a>00055 <span class="keywordflow">if</span> (!positive)<a name="l00056"></a>00056 coef = ring.Inverse(coef);<a name="l00057"></a>00057 <a name="l00058"></a>00058 <a class="code" href="class_polynomial_over.html#ac4ab97afda49a151fc9dbd8eaf9aa16" title="set the coefficient for x^i to value">SetCoefficient</a>(power, coef, ring);<a name="l00059"></a>00059 <a name="l00060"></a>00060 std::ws(in);<a name="l00061"></a>00061 <span class="keywordflow">switch</span> (in.get())<a name="l00062"></a>00062 {<a name="l00063"></a>00063 <span class="keywordflow">case</span> <span class="charliteral">'+'</span>:<a name="l00064"></a>00064 positive = <span class="keyword">true</span>;<a name="l00065"></a>00065 <span class="keywordflow">break</span>;<a name="l00066"></a>00066 <span class="keywordflow">case</span> <span class="charliteral">'-'</span>:<a name="l00067"></a>00067 positive = <span class="keyword">false</span>;<a name="l00068"></a>00068 <span class="keywordflow">break</span>;<a name="l00069"></a>00069 <span class="keywordflow">default</span>:<a name="l00070"></a>00070 <span class="keywordflow">return</span>; <span class="comment">// something's wrong with the input string</span><a name="l00071"></a>00071 }<a name="l00072"></a>00072 }<a name="l00073"></a>00073 }<a name="l00074"></a>00074 <a name="l00075"></a>00075 <span class="keyword">template</span> <<span class="keyword">class</span> T><a name="l00076"></a><a class="code" href="class_polynomial_over.html#65c6004a42608f31008ff066f2eba3e2">00076</a> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> <a class="code" href="class_polynomial_over.html#65c6004a42608f31008ff066f2eba3e2">PolynomialOver<T>::CoefficientCount</a>(<span class="keyword">const</span> <a class="code" href="class_polynomial_over.html#f87a6be38193e61c7aecb8c96510583e">Ring</a> &ring)<span class="keyword"> const</span><a name="l00077"></a>00077 <span class="keyword"></span>{<a name="l00078"></a>00078 <span class="keywordtype">unsigned</span> count = m_coefficients.size();<a name="l00079"></a>00079 <span class="keywordflow">while</span> (count && ring.Equal(m_coefficients[count-1], ring.Identity()))<a name="l00080"></a>00080 count--;<a name="l00081"></a>00081 <span class="keyword">const_cast<</span>std::vector<CoefficientType> &<span class="keyword">></span>(m_coefficients).resize(count);<a name="l00082"></a>00082 <span class="keywordflow">return</span> count;<a name="l00083"></a>00083 }<a name="l00084"></a>00084 <a name="l00085"></a>00085 <span class="keyword">template</span> <<span class="keyword">class</span> T><a name="l00086"></a><a class="code" href="class_polynomial_over.html#e35221cf35e25478e07de2e5fcebf0f9">00086</a> <span class="keyword">typename</span> <a class="code" href="class_polynomial_over.html" title="represents single-variable polynomials over arbitrary rings">PolynomialOver<T>::CoefficientType</a> <a class="code" href="class_polynomial_over.html#e35221cf35e25478e07de2e5fcebf0f9" title="return coefficient for x^i">PolynomialOver<T>::GetCoefficient</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i, <span class="keyword">const</span> <a class="code" href="class_polynomial_over.html#f87a6be38193e61c7aecb8c96510583e">Ring</a> &ring)<span class="keyword"> const </span><a name="l00087"></a>00087 <span class="keyword"></span>{<a name="l00088"></a>00088 <span class="keywordflow">return</span> (i < m_coefficients.size()) ? m_coefficients[i] : ring.Identity();<a name="l00089"></a>00089 }<a name="l00090"></a>00090 ⌨️ 快捷键说明
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