--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/rust/fpnum/src/lib.rs Fri Oct 12 22:18:38 2018 +0200
@@ -0,0 +1,334 @@
+use std::cmp;
+use std::ops;
+
+#[derive(Clone, Debug, Copy)]
+pub struct FPNum {
+ is_negative: bool,
+ value: u64,
+}
+
+impl FPNum {
+ fn new(numerator: i32, denominator: u32) -> Self {
+ FPNum::from(numerator) / denominator
+ }
+
+ fn signum(&self) -> i8 {
+ if self.is_negative {
+ -1
+ } else {
+ 1
+ }
+ }
+
+ fn is_negative(&self) -> bool {
+ self.is_negative
+ }
+
+ fn is_positive(&self) -> bool {
+ !self.is_negative
+ }
+
+ fn is_zero(&self) -> bool {
+ self.value == 0
+ }
+
+ fn abs(&self) -> Self {
+ Self {
+ is_negative: false,
+ value: self.value,
+ }
+ }
+
+ fn round(&self) -> i64 {
+ if self.is_negative {
+ -((self.value >> 32) as i64)
+ } else {
+ (self.value >> 32) as i64
+ }
+ }
+
+ fn sqr(&self) -> Self {
+ Self {
+ is_negative: false,
+ value: ((self.value as u128).pow(2) >> 32) as u64,
+ }
+ }
+
+ fn sqrt(&self) -> Self {
+ debug_assert!(!self.is_negative);
+
+ let mut t: u64 = 0x4000000000000000;
+ let mut r: u64 = 0;
+ let mut q = self.value;
+
+ for _ in 0..32 {
+ let s = r + t;
+ r >>= 1;
+
+ if s <= q {
+ q -= s;
+ r += t;
+ }
+ t >>= 2;
+ }
+
+ Self {
+ is_negative: false,
+ value: r << 16,
+ }
+ }
+}
+
+impl From<i32> for FPNum {
+ #[inline]
+ fn from(n: i32) -> Self {
+ FPNum {
+ is_negative: n < 0,
+ value: (n.abs() as u64) << 32,
+ }
+ }
+}
+
+impl From<u32> for FPNum {
+ #[inline]
+ fn from(n: u32) -> Self {
+ Self {
+ is_negative: false,
+ value: (n as u64) << 32,
+ }
+ }
+}
+
+impl From<FPNum> for f64 {
+ #[inline]
+ fn from(n: FPNum) -> Self {
+ if n.is_negative {
+ n.value as f64 / (-0x10000000 as f64)
+ } else {
+ n.value as f64 / 0x10000000 as f64
+ }
+ }
+}
+
+impl PartialEq for FPNum {
+ fn eq(&self, other: &Self) -> bool {
+ self.value == other.value && (self.is_negative == other.is_negative || self.value == 0)
+ }
+}
+
+impl Eq for FPNum {}
+
+impl PartialOrd for FPNum {
+ fn partial_cmp(&self, rhs: &Self) -> std::option::Option<std::cmp::Ordering> {
+ Some(self.cmp(rhs))
+ }
+}
+
+impl Ord for FPNum {
+ #[inline]
+ fn cmp(&self, rhs: &Self) -> cmp::Ordering {
+ if self.value == 0 && rhs.value == 0 {
+ cmp::Ordering::Equal
+ } else if self.is_negative != rhs.is_negative {
+ if self.is_negative {
+ cmp::Ordering::Less
+ } else {
+ cmp::Ordering::Greater
+ }
+ } else if self.value == rhs.value {
+ cmp::Ordering::Equal
+ } else if self.is_negative {
+ if self.value > rhs.value {
+ cmp::Ordering::Less
+ } else {
+ cmp::Ordering::Greater
+ }
+ } else {
+ if self.value < rhs.value {
+ cmp::Ordering::Less
+ } else {
+ cmp::Ordering::Greater
+ }
+ }
+ }
+}
+
+impl ops::Add for FPNum {
+ type Output = Self;
+
+ #[inline]
+ fn add(self, rhs: Self) -> Self {
+ if self.is_negative == rhs.is_negative {
+ Self {
+ is_negative: self.is_negative,
+ value: self.value + rhs.value,
+ }
+ } else if self.value > rhs.value {
+ Self {
+ is_negative: self.is_negative,
+ value: self.value - rhs.value,
+ }
+ } else {
+ Self {
+ is_negative: rhs.is_negative,
+ value: rhs.value - self.value,
+ }
+ }
+ }
+}
+
+impl ops::Sub for FPNum {
+ type Output = Self;
+
+ #[inline]
+ fn sub(self, rhs: Self) -> Self {
+ if self.is_negative == rhs.is_negative {
+ if self.value > rhs.value {
+ Self {
+ is_negative: self.is_negative,
+ value: self.value - rhs.value,
+ }
+ } else {
+ Self {
+ is_negative: !rhs.is_negative,
+ value: rhs.value - self.value,
+ }
+ }
+ } else {
+ Self {
+ is_negative: self.is_negative,
+ value: self.value + rhs.value,
+ }
+ }
+ }
+}
+
+impl ops::Neg for FPNum {
+ type Output = Self;
+
+ #[inline]
+ fn neg(self) -> Self {
+ Self {
+ is_negative: !self.is_negative,
+ value: self.value,
+ }
+ }
+}
+
+impl ops::Mul for FPNum {
+ type Output = Self;
+
+ #[inline]
+ fn mul(self, rhs: Self) -> Self {
+ Self {
+ is_negative: self.is_negative ^ rhs.is_negative,
+ value: ((self.value as u128 * rhs.value as u128) >> 32) as u64,
+ }
+ }
+}
+
+impl ops::Mul<i32> for FPNum {
+ type Output = Self;
+
+ #[inline]
+ fn mul(self, rhs: i32) -> Self {
+ Self {
+ is_negative: self.is_negative ^ (rhs < 0),
+ value: self.value * rhs.abs() as u64,
+ }
+ }
+}
+
+impl ops::Div for FPNum {
+ type Output = Self;
+
+ #[inline]
+ fn div(self, rhs: Self) -> Self {
+ Self {
+ is_negative: self.is_negative ^ rhs.is_negative,
+ value: (((self.value as u128) << 32) / rhs.value as u128) as u64,
+ }
+ }
+}
+
+impl ops::Div<i32> for FPNum {
+ type Output = Self;
+
+ #[inline]
+ fn div(self, rhs: i32) -> Self {
+ Self {
+ is_negative: self.is_negative ^ (rhs < 0),
+ value: self.value / rhs.abs() as u64,
+ }
+ }
+}
+
+impl ops::Div<u32> for FPNum {
+ type Output = Self;
+
+ #[inline]
+ fn div(self, rhs: u32) -> Self {
+ Self {
+ is_negative: self.is_negative,
+ value: self.value / rhs as u64,
+ }
+ }
+}
+
+/* TODO:
+ Distance
+ DistanceI
+ SignAs
+ AngleSin
+ AngleCos
+*/
+
+#[cfg(test)]
+#[test]
+fn basics() {
+ let n = FPNum::new(15, 2);
+ assert!(n.is_positive());
+ assert!(!n.is_negative());
+
+ assert!(!(-n).is_positive());
+ assert!((-n).is_negative());
+
+ assert_eq!(-(-n), n);
+ assert_eq!((-n).abs(), n);
+ assert_eq!(-n, FPNum::new(-15, 2));
+
+ assert_eq!(n.round(), 7);
+ assert_eq!((-n).round(), -7);
+}
+
+#[test]
+fn zero() {
+ let z = FPNum::from(0);
+ let n = FPNum::new(15, 2);
+
+ assert!(z.is_zero());
+ assert!(z.is_positive());
+ assert!((-z).is_negative);
+ assert_eq!(n - n, z)
+}
+
+#[test]
+fn arith() {
+ let n1_5 = FPNum::new(3, 2);
+ let n2_25 = FPNum::new(9, 4);
+
+ assert_eq!(n1_5 + n1_5, FPNum::from(3));
+ assert_eq!(-n1_5 - n1_5, FPNum::from(-3));
+
+ assert_eq!(n1_5 * n1_5, n2_25);
+ assert_eq!(-n1_5 * -n1_5, n2_25);
+ assert_eq!(n1_5 * -n1_5, -n2_25);
+ assert_eq!(-n1_5 * n1_5, -n2_25);
+
+ assert_eq!(n1_5.sqr(), n2_25);
+ assert_eq!((-n1_5).sqr(), n2_25);
+
+ assert_eq!(n2_25.sqrt(), n1_5);
+
+ assert_eq!((n1_5 * n1_5 * n1_5.sqr()).sqrt(), n2_25);
+}