assimp/code/irrXML/fast_atof.h

140 lines
2.3 KiB
C++

// Copyright (C) 2002-2005 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 <math.h>
namespace irr
{
namespace core
{
const float fast_atof_table[] = {
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
};
//! Provides a fast function for converting a string into a float,
//! about 6 times faster than atof in win32.
// If you find any bugs, please send them to me, niko (at) irrlicht3d.org.
inline char* fast_atof_move(char* c, float& out)
{
bool inv = false;
char *t;
float f;
if (*c=='-')
{
c++;
inv = true;
}
f = (float)strtol(c, &t, 10);
c = t;
if (*c == '.')
{
c++;
float pl = (float)strtol(c, &t, 10);
pl *= fast_atof_table[t-c];
f += pl;
c = t;
if (*c == 'e')
{
++c;
float exp = (float)strtol(c, &t, 10);
f *= (float)pow(10.0f, exp);
c = t;
}
}
if (inv)
f *= -1.0f;
out = f;
return c;
}
//! Provides a fast function for converting a string into a float,
//! about 6 times faster than atof in win32.
// If you find any bugs, please send them to me, niko (at) irrlicht3d.org.
inline const char* fast_atof_move_const(const char* c, float& out)
{
bool inv = false;
char *t;
float f;
if (*c=='-')
{
c++;
inv = true;
}
f = (float)strtol(c, &t, 10);
c = t;
if (*c == '.')
{
c++;
float pl = (float)strtol(c, &t, 10);
pl *= fast_atof_table[t-c];
f += pl;
c = t;
if (*c == 'e')
{
++c;
f32 exp = (f32)strtol(c, &t, 10);
f *= (f32)powf(10.0f, exp);
c = t;
}
}
if (inv)
f *= -1.0f;
out = f;
return c;
}
inline float fast_atof(const char* c)
{
float ret;
fast_atof_move_const(c, ret);
return ret;
}
} // end namespace core
}// end namespace irr
#endif