30 lines
695 B
V
30 lines
695 B
V
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module math
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const (
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modf_maxpowtwo = 4.503599627370496000e+15
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)
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// modf returns integer and fractional floating-point numbers
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// that sum to f. Both values have the same sign as f.
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//
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// special cases are:
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// modf(±inf) = ±inf, nan
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// modf(nan) = nan, nan
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pub fn modf(f f64) (f64, f64) {
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abs_f := abs(f)
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mut i := 0.0
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if abs_f >= math.modf_maxpowtwo {
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i = f // it must be an integer
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} else {
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i = abs_f + math.modf_maxpowtwo // shift fraction off right
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i -= math.modf_maxpowtwo // shift back without fraction
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for i > abs_f { // above arithmetic might round
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i -= 1.0 // test again just to be sure
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}
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if f < 0.0 {
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i = -i
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}
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}
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return i, f - i // signed fractional part
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}
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