104 lines
2.8 KiB
Rust
104 lines
2.8 KiB
Rust
use std::{fmt, fmt::Write, ops};
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pub struct Fx32(i32);
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impl Fx32
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{
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const FRACBITS: u32 = 16;
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const FRACMASK: u32 = 0xFFFF;
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const ONE: i32 = 1 << Fx32::FRACBITS;
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pub fn to_bits(&self) -> u32 {self.0 as u32}
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pub fn set_bits(&mut self, bits: u32) {self.0 = bits as i32}
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pub fn from_bits(bits: u32) -> Fx32 {Fx32(bits as i32)}
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pub fn integ(&self) -> i16 {(self.0 >> Fx32::FRACBITS) as i16}
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pub fn fract(&self) -> u16 {(self.0 as u32 & Fx32::FRACMASK) as u16}
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pub fn mul_i(&self, n: i32) -> Fx32 {Fx32(self.0 * n)}
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pub fn div_i(&self, n: i32) -> Fx32 {Fx32(self.0 / n)}
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}
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impl From<i32> for Fx32 {fn from(n: i32) -> Fx32 {Fx32(n << Fx32::FRACBITS)}}
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impl ops::Add for Fx32
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{type Output = Fx32; fn add(self, o: Fx32) -> Fx32 {Fx32(self.0 + o.0)}}
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impl ops::Sub for Fx32
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{type Output = Fx32; fn sub(self, o: Fx32) -> Fx32 {Fx32(self.0 - o.0)}}
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impl ops::Mul for Fx32
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{
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type Output = Fx32;
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fn mul(self, o: Fx32) -> Fx32
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{Fx32((self.0 as i64 * o.0 as i64 / Fx32::ONE as i64) as i32)}
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}
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impl ops::Div for Fx32
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{
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type Output = Fx32;
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fn div(self, o: Fx32) -> Fx32
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{Fx32((self.0 as i64 * Fx32::ONE as i64 / o.0 as i64) as i32)}
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}
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impl ops::Neg for Fx32
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{type Output = Fx32; fn neg(self) -> Fx32 {Fx32(-self.0)}}
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impl ops::Not for Fx32
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{type Output = Fx32; fn not(self) -> Fx32 {Fx32(!self.0)}}
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impl fmt::Display for Fx32
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{
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result
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{
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let prec = f.precision().unwrap_or(1);
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let widt = f.width().unwrap_or(0);
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write!(f, "{:widt$}.", self.integ(), widt = widt)?;
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let mut k = self.to_bits();
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for _ in 0..prec {
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k &= Fx32::FRACMASK;
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k *= 10;
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let d = k >> Fx32::FRACBITS;
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let d = d % 10;
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f.write_char((d as u8 + b'0') as char)?;
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}
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Ok(())
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}
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}
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impl fmt::Debug for Fx32
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{
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result
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{fmt::Display::fmt(self, f)}
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}
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#[test]
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fn fx32_basic_ops()
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{
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let seven_div_2 = 3 << Fx32::FRACBITS | Fx32::FRACMASK / 2 + 1;
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assert_eq!((Fx32::from(1) + 1.into()).to_bits(), 2 << Fx32::FRACBITS);
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assert_eq!((Fx32::from(2) - 1.into()).to_bits(), 1 << Fx32::FRACBITS);
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assert_eq!((Fx32::from(6) * 2.into()).to_bits(), 12 << Fx32::FRACBITS);
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assert_eq!((Fx32::from(6).mul_i(2) ).to_bits(), 12 << Fx32::FRACBITS);
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assert_eq!((Fx32::from(7) / 2.into()).to_bits(), seven_div_2);
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assert_eq!((Fx32::from(7).div_i(2) ).to_bits(), seven_div_2);
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}
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#[test]
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#[should_panic]
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#[allow(unused_must_use)]
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fn fx32_overflow()
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{
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Fx32::from(32767) + 1.into();
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}
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#[test]
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fn fx32_printing()
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{
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assert_eq!(format!("{}", Fx32::from(6)), "6.0");
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assert_eq!(format!("{}", Fx32::from(7).div_i(2)), "3.5");
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assert_eq!(format!("{:7.7}", Fx32::from_bits(0xDEAD_BEEF)), " -8531.7458343");
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}
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// EOF
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