1 files changed, 92 insertions, 0 deletions
diff --git a/lib/src/lib.rs b/lib/src/lib.rs
new file mode 100644
index 0000000..a8d48b6
--- /dev/null
+++ b/lib/src/lib.rs
@@ -0,0 +1,92 @@
+
+
+const HEADERS: [&[u8]; 3] = [b"asd", b"adf", b"ads"];
+const HOME_RIGHT: [u8; 4] = [b'a',b's',b'd',b'f'];
+const HOME_LEFT: [u8; 4] = [b'h',b'j',b'k',b'l'];
+const ABOVE_RIGHT: [u8; 4] = [b'w',b'e',b'r',b't'];
+const ABOVE_LEFT: [u8; 4] = [b'u',b'i',b'o',b'p'];
+
+pub fn encode(buf: &[u8]) -> Vec<u8> {
+    let mut out = Vec::new();
+
+    let h = HEADERS[fastrand::usize(..HEADERS.len())];
+    for s in h {
+        out.push(*s);
+    }
+
+
+    for byte in buf {
+        let stuff = encode_byte(*byte);
+        for b in stuff {
+            out.push(b);
+        }
+    }
+    out
+}
+
+fn encode_byte(byte: u8) -> [u8; 4] {
+    [some_dict()[((byte & 0b11000000) >> 6) as usize],
+     some_dict()[((byte & 0b00110000) >> 4) as usize],
+     some_dict()[((byte & 0b00001100) >> 2) as usize],
+     some_dict()[(byte & 0b00000011) as usize]
+    ]
+}
+
+fn some_dict() -> &'static [u8; 4] {
+    let q = fastrand::usize(0..10);
+    if q < 4 {
+        return &HOME_RIGHT
+    }
+    if q < 8 {
+        return &HOME_LEFT
+    }
+    if q < 9 {
+        return &ABOVE_RIGHT
+    }
+    return &ABOVE_LEFT
+}
+
+pub fn decode(buf: &[u8]) -> Vec<u8> {
+    let buf = &buf[3..];
+
+    let mut out = Vec::new();
+    for pair in buf.chunks(4) {
+        out.push((decode_sym(pair[0]) << 6)
+            + (decode_sym(pair[1]) << 4)
+            + (decode_sym(pair[2]) << 2)
+            + decode_sym(pair[3]));
+    }
+    out
+}
+
+pub fn decode_sym(sym: u8) -> u8 {
+    let find = |d: &[u8; 4]| -> Option<u8> {
+        d.iter().enumerate().find(|s| s.1 == &sym).map(|s| s.0 as u8)
+    };
+    find(&HOME_RIGHT)
+        .or_else(|| find(&HOME_LEFT))
+        .or_else(|| find(&ABOVE_RIGHT))
+        .or_else(|| find(&ABOVE_LEFT))
+        .unwrap()
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let hello = b"hello, world!";
+        assert_eq!(&hello[..], &decode(&encode(hello)));
+    }
+
+    #[test]
+    fn random() {
+        for _ in 0..1000 {
+            let mut buf = vec![0; fastrand::usize(..1000)];
+            buf.iter_mut().for_each(|s| *s = fastrand::u8(..));
+            assert_eq!(&buf[..], &decode(&encode(&buf)));
+        }
+    }
+}