move ported cpp_shared resources

src/common/cpp_essentials/util.rs

@@ -0,0 +1,43 @@
+use crate::common::Result;
+use crate::{Exceptions, Point};
+
+use super::{DMRegressionLine, Direction, RegressionLine};
+
+#[inline(always)]
+pub fn float_min<T: PartialOrd>(a: T, b: T) -> T {
+    if a > b {
+        b
+    } else {
+        a
+    }
+}
+
+#[inline(always)]
+pub fn float_max<T: PartialOrd>(a: T, b: T) -> T {
+    if a < b {
+        b
+    } else {
+        a
+    }
+}
+
+#[inline(always)]
+pub fn intersect(l1: &DMRegressionLine, l2: &DMRegressionLine) -> Result<Point> {
+    if !(l1.isValid() && l2.isValid()) {
+        return Err(Exceptions::ILLEGAL_STATE);
+    }
+    let d = l1.a * l2.b - l1.b * l2.a;
+    let x = (l1.c * l2.b - l1.b * l2.c) / d;
+    let y = (l1.a * l2.c - l1.c * l2.a) / d;
+    Ok(Point { x, y })
+}
+
+#[allow(dead_code)]
+#[inline(always)]
+pub fn opposite(dir: Direction) -> Direction {
+    if dir == Direction::Left {
+        Direction::Right
+    } else {
+        Direction::Left
+    }
+}