115 lines
2.1 KiB
C
115 lines
2.1 KiB
C
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// Copyright (C) 2002-2007 Nikolaus Gebhardt
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// This file is part of the "Irrlicht Engine" and the "irrXML" project.
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// For conditions of distribution and use, see copyright notice in irrlicht.h and irrXML.h
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// Adapted to the ASSIMP library because the builtin atof indeed takes AGES to parse a
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// float inside a large string. Before parsing, it does a strlen on the given point.
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#ifndef __FAST_A_TO_F_H_INCLUDED__
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#define __FAST_A_TO_F_H_INCLUDED__
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#include <math.h>
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namespace Assimp
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{
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const float fast_atof_table[16] = { // we write [16] here instead of [] to work around a swig bug
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0.f,
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0.1f,
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0.01f,
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0.001f,
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0.0001f,
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0.00001f,
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0.000001f,
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0.0000001f,
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0.00000001f,
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0.000000001f,
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0.0000000001f,
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0.00000000001f,
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0.000000000001f,
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0.0000000000001f,
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0.00000000000001f,
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0.000000000000001f
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};
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inline unsigned int strtol10( const char* in, const char** out=0)
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{
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unsigned int value = 0;
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while ( 1 )
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{
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if ( *in < '0' || *in > '9' )
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break;
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value = ( value * 10 ) + ( *in - '0' );
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++in;
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}
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if (out)
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*out = in;
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return value;
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}
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//! Provides a fast function for converting a string into a float,
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//! about 6 times faster than atof in win32.
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// If you find any bugs, please send them to me, niko (at) irrlicht3d.org.
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inline const char* fast_atof_move( const char* c, float& out)
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{
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bool inv = false;
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const char *t;
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float f;
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if (*c=='-')
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{
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++c;
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inv = true;
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}
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//f = (float)strtol(c, &t, 10);
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f = (float) strtol10 ( c, &c );
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if (*c == '.')
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{
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++c;
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//float pl = (float)strtol(c, &t, 10);
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float pl = (float) strtol10 ( c, &t );
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pl *= fast_atof_table[t-c];
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f += pl;
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c = t;
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if (*c == 'e')
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{
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++c;
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//float exp = (float)strtol(c, &t, 10);
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bool einv = (*c=='-');
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if (einv)
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++c;
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float exp = (float)strtol10(c, &c);
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if (einv)
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exp *= -1.0f;
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f *= pow(10.0f, exp);
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}
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}
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if (inv)
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f *= -1.0f;
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out = f;
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return c;
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}
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inline float fast_atof(const char* c)
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{
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float ret;
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fast_atof_move(c, ret);
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return ret;
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}
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} // end of namespace Assimp
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#endif
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