OpenSceneGraph/src/osg/Math.cpp
2010-05-28 15:47:52 +00:00

115 lines
3.1 KiB
C++

/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
*
* This library is open source and may be redistributed and/or modified under
* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
* (at your option) any later version. The full license is in LICENSE file
* included with this distribution, and on the openscenegraph.org website.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* OpenSceneGraph Public License for more details.
*/
#include <osg/Math>
#include <string.h>
double osg::asciiToDouble(const char* str)
{
const char* ptr = str;
// check if could be a hex number.
if (strncmp(ptr,"0x",2)==0)
{
double value = 0.0;
// skip over leading 0x, and then go through rest of string
// checking to make sure all values are 0...9 or a..f.
ptr+=2;
while (
*ptr!=0 &&
((*ptr>='0' && *ptr<='9') ||
(*ptr>='a' && *ptr<='f') ||
(*ptr>='A' && *ptr<='F'))
)
{
if (*ptr>='0' && *ptr<='9') value = value*16.0 + double(*ptr-'0');
else if (*ptr>='a' && *ptr<='f') value = value*16.0 + double(*ptr-'a'+10);
else if (*ptr>='A' && *ptr<='F') value = value*16.0 + double(*ptr-'A'+10);
++ptr;
}
// OSG_NOTICE<<"Read "<<str<<" result = "<<value<<std::endl;
return value;
}
ptr = str;
bool hadDecimal[2];
double value[2];
double sign[2];
double decimalMultiplier[2];
hadDecimal[0] = hadDecimal[1] = false;
sign[0] = sign[1] = 1.0;
value[0] = value[1] = 0.0;
decimalMultiplier[0] = decimalMultiplier[1] = 0.1;
int pos = 0;
// compute mantissa and exponent parts
while (*ptr!=0 && pos<2)
{
if (*ptr=='+')
{
sign[pos] = 1.0;
}
else if (*ptr=='-')
{
sign[pos] = -1.0;
}
else if (*ptr>='0' && *ptr<='9')
{
if (!hadDecimal[pos])
{
value[pos] = value[pos]*10.0 + double(*ptr-'0');
}
else
{
value[pos] = value[pos] + decimalMultiplier[pos] * double(*ptr-'0');
decimalMultiplier[pos] *= 0.1;
}
}
else if (*ptr=='.')
{
hadDecimal[pos] = true;
}
else if (*ptr=='e' || *ptr=='E')
{
if (pos==1) break;
pos = 1;
}
else
{
break;
}
++ptr;
}
if (pos==0)
{
// OSG_NOTICE<<"Read "<<str<<" result = "<<value[0]*sign[0]<<std::endl;
return value[0]*sign[0];
}
else
{
double mantissa = value[0]*sign[0];
double exponent = value[1]*sign[1];
//OSG_NOTICE<<"Read "<<str<<" mantissa = "<<mantissa<<" exponent="<<exponent<<" result = "<<mantissa*pow(10.0,exponent)<<std::endl;
return mantissa*pow(10.0,exponent);
}
}