Initial commit.

src/main.rs

@@ -0,0 +1,97 @@
+fn main() {
+    println!("{:?}", get_byte(2));
+}
+
+fn get_byte(id: i32) -> u8 {
+    let pid : f64 = 4.0 * series(1, id) - 2.0 * series(4, id) - series(5, id) - series(6, id);
+
+    let mut y : f64 = (pid - (pid as i32) as f64 + 1.0).abs();
+
+    y = 16.0 * (y - y.floor());
+
+    let first : u8 = y as u8;
+
+    y = 16.0 * (y - y.floor());
+
+    let second : u8 = y as u8;
+
+    (first << 4) | second
+}
+
+
+fn series(m: i32, id: i32) -> f64 {
+    const EPS : f64 = 1e-17;
+
+    let mut ak : f64;
+    let mut p : f64;
+    let mut s : f64 = 0.0;
+    let mut t : f64;
+
+    for k in 0..id {
+      ak = (8 * k + m) as f64;
+      p = (id - k) as f64;
+      t = expm(p, ak);
+      s = s + t / ak;
+      s = s - (s as i32) as f64;
+    }
+
+    for k in id..id + 101 {
+      ak = (8 * k + m) as f64;
+      t = 16f64.powi(id - k) / ak;
+
+      if t < EPS {
+          break;
+      }
+
+      s = s + t;
+      s = s - (s as i32) as f64;
+    }
+
+    s
+}
+
+fn expm(p: f64, ak: f64) -> f64 {
+    const NTP : usize = 25;
+
+    let mut tp = vec![1f64; NTP];
+    let mut i : i32 = 0;
+    let mut p1 : f64;
+    let mut pt : f64;
+    let mut r : f64;
+
+    for n in 1..NTP {
+        tp[n] = 2.0 * tp[n - 1];
+    }
+
+    if ak == 1.0 {
+        return 0.0;
+    }
+
+    for n in 0..NTP {
+        if tp[n] > p {
+            i = n as i32;
+            break;
+        }
+    }
+
+    pt = tp[(i - 1) as usize];
+    p1 = p;
+    r = 1.0;
+
+    for _ in 1..i + 1 {
+      if p1 >= pt {
+        r = 16.0 * r;
+        r = r - ((r / ak) as i32) as f64 * ak;
+        p1 = p1 - pt;
+      }
+
+      pt = 0.5 * pt;
+
+      if pt >= 1.0 {
+        r = r * r;
+        r = r - ((r / ak) as i32) as f64 * ak;
+      }
+    }
+
+    r
+}