wymath.cpp

一个不错

/* Copyright license: GNU LGPL (see file COPYING)           by I.J.Wang (2004)
*/

#define WYLIB_SOURCE
#include "wymath.h"
#include "wy__scanum.h"
#include <math.h>    // for isnan(..)..

//
// See wynum.h for declaration
//
inline static bool wy__testfail_neg(float) { return false; };
inline static bool wy__testfail_neg(double) { return false; };

namespace Wy {

// Accept: [+-]ddd.ddd[(eE)[+-]ggg]
//
//  ddd is internally converted to long long, digits of ddd>18 may overflow
//
WyRet _strnum(double& res, const char** endptr, WyCSeg cseg)
{
 typedef double FopType;      // Type for float operation
 typedef long long ResInt;    // Integer type for result of text conversion
 const char* buf=cseg.begin();
 const size_t blen=cseg.size();
 WyRet r;
 ResInt res1,res2;
 int fdig,texp;
 size_t sblen(blen);

 for(;;) {
   r=Wy::wy_strnum3(res1,res2,fdig,texp,endptr,buf,sblen);
   const int dpp=fdig+texp;
   if(texp<=0) {
     if(dpp>fdig) {
       if(sblen<7) {
         WY_THROW( WyRet() );
       }
       --sblen;
       continue;
     }
   } else {
     if(dpp<=fdig) {
       if(sblen<7) {
         WY_THROW( WyRet() );
       }
       --sblen;
       continue;
     }
   }

   res=(static_cast<FopType>(res1)*std::pow(10.0,static_cast<double>(texp))+
        static_cast<FopType>(res2)*std::pow(10.0,static_cast<double>(dpp)) );
   //if(finite(res)==0)
   if(isinf(res)||isnan(res)) {
     --sblen;
     continue;
   }

   if(r==Ok) {
     break;
   }
   if(sblen==blen) {
     break;
   }
 }
 if(sblen!=blen) {
   WY_RETURN(Wym_ERANGE);
 }
 return(r);
};

//
// Accept: [+-]ddd.ddd[(eE)[+-]ggg]
//
//  ddd is internally converted to long long, digits of ddd>18 may overflow
//
WyRet _strnum(float& res, const char** endptr, WyCSeg cseg)
{
 typedef double FopType;      // Type for float operation
 typedef long long ResInt;    // Integer type for result of text conversion
 const char* buf=cseg.begin();
 const size_t blen=cseg.size();
 WyRet r;
 ResInt res1,res2;
 int fdig,texp;
 size_t sblen(blen);

 for(;;) {
   r=Wy::wy_strnum3(res1,res2,fdig,texp,endptr,buf,sblen);
   const int dpp=fdig+texp;
   if(texp<=0) {
     if(dpp>fdig) {
       if(sblen<7) {
         WY_THROW( WyRet() );
       }
       --sblen;
       continue;
     }
   } else {
     if(dpp<=fdig) {
       if(sblen<7) {
         WY_THROW( WyRet() );
       }
       --sblen;
       continue;
     }
   }

   res=(static_cast<FopType>(res1)*std::pow(10.0,static_cast<double>(texp))+
        static_cast<FopType>(res2)*std::pow(10.0,static_cast<double>(dpp)) );
   //if(finite(res)==0)
   if(isinf(res)||isnan(res)) {
     --sblen;
     continue;
   }

   if(r==Ok) {
     break;
   }
   if(sblen==blen) {
     break;
   }
 }
 if(sblen!=blen) {
   WY_RETURN(Wym_ERANGE);
 }
 return(r);
};

WyRet _strnum(float& res, const char** endptr, WyCSeg cseg, const int& radix)
 {
   if((radix!=10)&&(radix!=0)) {
     WY_RETURN( Wym_EINVAL );
   }
   return _strnum(res,endptr,cseg); 
 };
WyRet _strnum(double& res, const char** endptr, WyCSeg cseg, const int& radix)
 {
   if((radix!=10)&&(radix!=0)) {
     WY_RETURN( Wym_EINVAL );
   }
   return _strnum(res,endptr,cseg); 
 };

WyRet _strnum(float& res, const char** endptr, WyCSeg cseg, int& radix)
 {
   if(radix!=10) {
     if(radix!=0) {
       WY_RETURN( Wym_EINVAL );
     }
     radix=10;
   }
   return _strnum(res,endptr,cseg); 
 };

WyRet _strnum(double& res, const char** endptr, WyCSeg cseg, int& radix)
 {
   if(radix!=10) {
     if(radix!=0) {
       WY_RETURN( Wym_EINVAL );
     }
     radix=10;
   }
   return _strnum(res,endptr,cseg); 
 };

bool wy_roughly_equ(double a, double b) WY__TSPC()
{
 const double ErrorRatio=1e-7;
 if(b==0) {
   return (a>-ErrorRatio)&&(a<ErrorRatio);
 } else {
   const double er((b-a)/b);
   return (er>-ErrorRatio)&&(er<ErrorRatio);
 }
};

//-----------
WyRet _scanum(float& n, size_t& idx, const WyCSeg& text, const int& radix)
{ return wy__scanum(n,idx,text,radix); };
WyRet _scanum(double& n, size_t& idx, const WyCSeg& text, const int& radix)
{ return wy__scanum(n,idx,text,radix); };

WyRet _scanum(float& n, size_t& idx, const WyCSeg& text)
{ return wy__scanum(n,idx,text,0); };
WyRet _scanum(double& n, size_t& idx, const WyCSeg& text)
{ return wy__scanum(n,idx,text,0); };
}; // End of Wy