irrlicht/tests/fast_atof.cpp

177 lines
4.7 KiB
C++

// Copyright (C) 2008-2009 Colin MacDonald
// No rights reserved: this software is in the public domain.
#include "testUtils.h"
using namespace irr;
using namespace core;
//! This was an older Irrlicht implementation, tested against for reference.
static inline u32 old_strtol10(const char* in, const char** out=0)
{
u32 value = 0;
while ( ( *in >= '0') && ( *in <= '9' ))
{
value = ( value * 10 ) + ( *in - '0' );
++in;
}
if (out)
*out = in;
return value;
}
//! This was an older Irrlicht implementation, tested against for reference.
static inline const char* old_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) old_strtol10 ( c, &c );
if (*c == '.')
{
++c;
//float pl = (float)strtol(c, &t, 10);
float pl = (float) old_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)old_strtol10(c, &c);
if (einv)
exp *= -1.0f;
f *= (float)pow(10.0f, exp);
}
}
if (inv)
f *= -1.0f;
out = f;
return c;
}
//! This was an older Irrlicht implementation, tested against for reference.
static inline float old_fast_atof(const char* c)
{
float ret;
old_fast_atof_move(c, ret);
return ret;
}
static bool testCalculation(const char * valueString)
{
const f32 newFastValue = fast_atof(valueString);
const f32 oldFastValue = old_fast_atof(valueString);
const f32 atofValue = (f32)atof(valueString);
logTestString("\n String '%s'\n New fast %.40f\n Old fast %.40f\n atof %.40f\n",
valueString, newFastValue, oldFastValue, atofValue);
bool accurate = fabs(newFastValue - atofValue) <= fabs(oldFastValue - atofValue);
if(!accurate)
logTestString("*** ERROR - less accurate than old method ***\n\n");
return accurate;
}
//! Test both the accuracy and speed of Irrlicht's fast_atof() implementation.
bool fast_atof(void)
{
bool accurate = true;
accurate &= testCalculation("340282346638528859811704183484516925440.000000");
accurate &= testCalculation("3.402823466e+38F");
accurate &= testCalculation("3402823466e+29F");
accurate &= testCalculation("-340282346638528859811704183484516925440.000000");
accurate &= testCalculation("-3.402823466e+38F");
accurate &= testCalculation("-3402823466e+29F");
accurate &= testCalculation("34028234663852885981170418348451692544.000000");
accurate &= testCalculation("3.402823466e+37F");
accurate &= testCalculation("3402823466e+28F");
accurate &= testCalculation("-34028234663852885981170418348451692544.000000");
accurate &= testCalculation("-3.402823466e+37F");
accurate &= testCalculation("-3402823466e+28F");
accurate &= testCalculation(".00234567");
accurate &= testCalculation("-.00234567");
accurate &= testCalculation("0.00234567");
accurate &= testCalculation("-0.00234567");
accurate &= testCalculation("1.175494351e-38F");
accurate &= testCalculation("1175494351e-47F");
accurate &= testCalculation("1.175494351e-37F");
accurate &= testCalculation("1.175494351e-36F");
accurate &= testCalculation("-1.175494351e-36F");
accurate &= testCalculation("123456.789");
accurate &= testCalculation("-123456.789");
accurate &= testCalculation("0000123456.789");
accurate &= testCalculation("-0000123456.789");
accurate &= testCalculation("-0.0690462109446526");
if(!accurate)
{
logTestString("Calculation is not accurate, so the speed is irrelevant\n");
return false;
}
IrrlichtDevice* device = createDevice(video::EDT_NULL);
if (!device)
return false;
ITimer* timer = device->getTimer();
enum { ITERATIONS = 100000 };
int i;
f32 value;
u32 then = timer->getRealTime();
for(i = 0; i < ITERATIONS; ++i)
value = (f32)atof("-340282346638528859811704183484516925440.000000");
const u32 atofTime = timer->getRealTime() - then;
then += atofTime;
for(i = 0; i < ITERATIONS; ++i)
value = fast_atof("-340282346638528859811704183484516925440.000000");
const u32 fastAtofTime = timer->getRealTime() - then;
then += fastAtofTime;
for(i = 0; i < ITERATIONS; ++i)
value = old_fast_atof("-340282346638528859811704183484516925440.000000");
const u32 oldFastAtofTime = timer->getRealTime() - then;
logTestString(" atof time = %d\n fast_atof Time = %d\nold fast_atof time = %d\n",
atofTime, fastAtofTime, oldFastAtofTime);
device->drop();
if(fastAtofTime > (1.2f*atofTime))
{
logTestString("The fast method is slower than atof()\n");
return false;
}
return true;
}