Number.hpp Source File

00001 /*==========================================================================
00002  * Copyright (c) 2001 Carnegie Mellon University.  All Rights Reserved.
00003  *
00004  * Use of the Lemur Toolkit for Language Modeling and Information Retrieval
00005  * is subject to the terms of the software license set forth in the LICENSE
00006  * file included with this software, and also available at
00007  * http://www.cs.cmu.edu/~lemur/license.html
00008  *
00009  *==========================================================================
00010 */
00011 
00012 
00013 // ----------------------------------------------------------------------
00014 // Number.hpp
00015 // 10.5.95 
00016 // ----------------------------------------------------------------------
00017 
00018 #ifndef _NUMBERH_
00019 #define _NUMBERH_
00020 
00021 // #pragma interface
00022 
00023 #include "common_headers.hpp"
00024 
00025 template <class U>
00026 class Number
00027 {
00028 public:
00029   Number() {}
00030   Number(const U& u_p) { u = u_p; }
00031 
00032   int hash() const 
00033     {
00034         int i, hashval=1, nBytes=sizeof(u);
00035         char *p = (char*) &u;
00036         for (i=0; i<nBytes; i++)
00037           hashval = p[i] + 31*hashval;
00038         if (hashval<0) hashval*=-1;
00039         return hashval;
00040     }
00041   int Hash() const { return hash(); }
00042 
00043   void read(istream &is)  { is.read(&u, sizeof(u));  }
00044   void write(ostream &os)  { os.write(&u, sizeof(u));  }
00045 
00046   int operator<(const Number<U>& that)  const { return (u< that.u? 1: 0); }
00047   int operator<=(const Number<U>& that) const { return (u<=that.u? 1: 0); }
00048   int operator>(const Number<U>& that)  const { return (u> that.u? 1: 0); }
00049   int operator>=(const Number<U>& that) const { return (u>=that.u? 1: 0); }
00050   int operator==(const Number<U>& that) const { return (u==that.u? 1: 0); }
00051   int operator!=(const Number<U>& that) const { return (u!=that.u? 1: 0); }
00052 
00053   Number<U> operator+=(const Number<U>& that) { u+=that.u; return u; }
00054   Number<U> operator-=(const Number<U>& that) { u-=that.u; return u; }
00055   Number<U> operator*=(const Number<U>& that) { u*=that.u; return u; }
00056   Number<U> operator/=(const Number<U>& that) { u/=that.u; return u; }
00057 
00058   Number<U> operator+(const Number<U>& that)  { return u+that.u; }
00059   Number<U> operator-(const Number<U>& that)  { return u-that.u; }
00060   Number<U> operator*(const Number<U>& that)  { return u*that.u; }
00061   Number<U> operator/(const Number<U>& that)  { return u/that.u; }
00062 
00063 
00064   template <U> friend ostream& operator<<(ostream&, const Number<U>&) {
00065     os << s.u; return os;}
00066   // changed to remove dependence on GUIDE_DECLS, C. Zhai, 2/20/2001
00067   
00068   // friend ostream& operator<<(ostream&, const Number<U>&);
00069   // this old version didn't work! (C. Zhai)
00070 
00071   operator U() const { return u; }
00072   
00073 private:
00074   U u;
00075 };
00076 
00077 // the following doesn't seem to work
00078 
00079 /* It's now inside the class declaration. C. Zhai, 2/20/2001
00080 template <class U>
00081 ostream& operator<<(ostream& os,  const Number<U>& s) {os<<s.u;return os;}
00082 */
00083 
00084 #endif
00085