1 files changed, 92 insertions, 0 deletions
diff --git a/vendor/libm/src/math/atan2f.rs b/vendor/libm/src/math/atan2f.rs
new file mode 100644
index 000000000..7bbe5f1d4
--- /dev/null
+++ b/vendor/libm/src/math/atan2f.rs
@@ -0,0 +1,92 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_atan2f.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+use super::atanf;
+use super::fabsf;
+
+const PI: f32 = 3.1415927410e+00; /* 0x40490fdb */
+const PI_LO: f32 = -8.7422776573e-08; /* 0xb3bbbd2e */
+
+/// Arctangent of y/x (f32)
+///
+/// Computes the inverse tangent (arc tangent) of `y/x`.
+/// Produces the correct result even for angles near pi/2 or -pi/2 (that is, when `x` is near 0).
+/// Returns a value in radians, in the range of -pi to pi.
+#[inline]
+#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
+pub fn atan2f(y: f32, x: f32) -> f32 {
+    if x.is_nan() || y.is_nan() {
+        return x + y;
+    }
+    let mut ix = x.to_bits();
+    let mut iy = y.to_bits();
+
+    if ix == 0x3f800000 {
+        /* x=1.0 */
+        return atanf(y);
+    }
+    let m = ((iy >> 31) & 1) | ((ix >> 30) & 2); /* 2*sign(x)+sign(y) */
+    ix &= 0x7fffffff;
+    iy &= 0x7fffffff;
+
+    /* when y = 0 */
+    if iy == 0 {
+        return match m {
+            0 | 1 => y,   /* atan(+-0,+anything)=+-0 */
+            2 => PI,      /* atan(+0,-anything) = pi */
+            3 | _ => -PI, /* atan(-0,-anything) =-pi */
+        };
+    }
+    /* when x = 0 */
+    if ix == 0 {
+        return if m & 1 != 0 { -PI / 2. } else { PI / 2. };
+    }
+    /* when x is INF */
+    if ix == 0x7f800000 {
+        return if iy == 0x7f800000 {
+            match m {
+                0 => PI / 4.,           /* atan(+INF,+INF) */
+                1 => -PI / 4.,          /* atan(-INF,+INF) */
+                2 => 3. * PI / 4.,      /* atan(+INF,-INF)*/
+                3 | _ => -3. * PI / 4., /* atan(-INF,-INF)*/
+            }
+        } else {
+            match m {
+                0 => 0.,      /* atan(+...,+INF) */
+                1 => -0.,     /* atan(-...,+INF) */
+                2 => PI,      /* atan(+...,-INF) */
+                3 | _ => -PI, /* atan(-...,-INF) */
+            }
+        };
+    }
+    /* |y/x| > 0x1p26 */
+    if (ix + (26 << 23) < iy) || (iy == 0x7f800000) {
+        return if m & 1 != 0 { -PI / 2. } else { PI / 2. };
+    }
+
+    /* z = atan(|y/x|) with correct underflow */
+    let z = if (m & 2 != 0) && (iy + (26 << 23) < ix) {
+        /*|y/x| < 0x1p-26, x < 0 */
+        0.
+    } else {
+        atanf(fabsf(y / x))
+    };
+    match m {
+        0 => z,                /* atan(+,+) */
+        1 => -z,               /* atan(-,+) */
+        2 => PI - (z - PI_LO), /* atan(+,-) */
+        _ => (z - PI_LO) - PI, /* case 3 */ /* atan(-,-) */
+    }
+}