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fast_atof.h

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// Copyright (C) 2002-2008 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine" and the "irrXML" project.
// For conditions of distribution and use, see copyright notice in irrlicht.h and irrXML.h

#ifndef __FAST_A_TO_F_H_INCLUDED__
#define __FAST_A_TO_F_H_INCLUDED__

#include <stdlib.h>
#include "irrMath.h"

namespace irr
{
namespace core
{

// we write [16] here instead of [] to work around a swig bug
const float fast_atof_table[16] = {
        0.f,
        0.1f,
        0.01f,
        0.001f,
        0.0001f,
        0.00001f,
        0.000001f,
        0.0000001f,
        0.00000001f,
        0.000000001f,
        0.0000000001f,
        0.00000000001f,
        0.000000000001f,
        0.0000000000001f,
        0.00000000000001f,
        0.000000000000001f
};

inline u32 strtol10(const char* in, const char** out=0)
{
        u32 value = 0;

        while ( 1 )
        {
                if ( *in < '0' || *in > '9' )
                        break;

                value = ( value * 10 ) + ( *in - '0' );
                ++in;
        }
        if (out)
                *out = in;
        return value;
}

// If you find any bugs, please send them to me, niko (at) irrlicht3d.org.
inline const char* fast_atof_move( const char* c, float& out)
{
        bool inv = false;
        const char *t;
        float f;

        if (*c=='-')
        {
                ++c;
                inv = true;
        }

        //f = (float)strtol(c, &t, 10);
        f = (float) strtol10 ( c, &c );

        if (*c == '.')
        {
                ++c;

                //float pl = (float)strtol(c, &t, 10);
                float pl = (float) strtol10 ( c, &t );
                pl *= fast_atof_table[t-c];

                f += pl;

                c = t;

                if (*c == 'e')
                {
                        ++c;
                        //float exp = (float)strtol(c, &t, 10);
                        bool einv = (*c=='-');
                        if (einv)
                                ++c;

                        float exp = (float)strtol10(c, &c);
                        if (einv)
                                exp *= -1.0f;

                        f *= (float)pow(10.0f, exp);
                }
        }

        if (inv)
                f *= -1.0f;

        out = f;
        return c;
}

inline float fast_atof(const char* c)
{
        float ret;
        fast_atof_move(c, ret);
        return ret;
}

} // end namespace core
} // end namespace irr

#endif

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The Irrlicht Engine Documentation © 2003-2008 by Nikolaus Gebhardt. Generated on Sun Sep 21 08:57:41 2008 by Doxygen (1.4.2)