float LCG::FloatNeg1_1()
{
u32 i = (u32)Int();
u32 one = ((i & 0x00800000) << 8) /* random sign bit */ | 0x3F800000 /* fixed exponent */;
i = one | (i & 0x007FFFFF) /* random mantissa */;
float f = ReinterpretAsFloat(i); // f is now in range ]-2, -1[ union [1, 2].
float fone = ReinterpretAsFloat(one); // +/- 1, of same sign as f.
return f - fone;
}
float LCG::Float()
{
u32 i = ((u32)Int() & 0x007FFFFF /* random mantissa */) | 0x3F800000 /* fixed exponent */;
float f = ReinterpretAsFloat(i); // f is now in range [1, 2[
f -= 1.f; // Map to range [0, 1[
return f;
}
float LCG::Float01Incl()
{
for(int i = 0; i < 100; ++i)
{
u32 val = (u32)Int() & 0x00FFFFFF;
if (val > 0x800000)
continue;
else if (val == 0x800000)
return 1.0f;
else
{
val |= 0x3F800000;
return ReinterpretAsFloat(val) - 1.f;
}
}
return Float();
}
float DeserializeFloat(const char *str, const char **outEndStr)
{
if (!str)
return FLOAT_NAN;
while(*str > 0 && *str <= ' ')
++str;
if (*str == 0)
return FLOAT_NAN;
if (MATH_NEXT_WORD_IS(str, "NaN("))
{
str += strlen("NaN("); //MATH_SKIP_WORD(str, "NaN(");
u32 x;
int n = sscanf(str, "%X", (unsigned int *)&x);
if (n != 1)
return FLOAT_NAN;
while(*str != 0)
{
++str;
if (*str == ')')
{
++str;
break;
}
}
if (outEndStr)
*outEndStr = str;
return ReinterpretAsFloat(x);
}
float f;
if (!strncmp(str, "-inf", 4)) { f = -FLOAT_INF; str += 4; }
else if (!strncmp(str, "inf", 3)) { f = FLOAT_INF; str += 3; }
else f = (float)strtod(str, const_cast<char**>(&str));
while(*str > 0 && *str <= ' ')
++str;
if (*str == ',' || *str == ';')
++str;
while(*str > 0 && *str <= ' ')
++str;
if (outEndStr)
*outEndStr = str;
return f;
}