keyfork-mnemonic-generate: extract converters

keyfork-mnemonic-generate/src/main.rs

@@ -70,6 +70,34 @@ fn build_wordlist() -> Vec<String> {
         .collect()
 }
 
+#[allow(clippy::trivially_copy_pass_by_ref)]
+fn u8_to_bitslice(byte: &u8) -> [bool; 8] {
+    [
+        byte & (1 << 0) != 0,
+        byte & (1 << 1) != 0,
+        byte & (1 << 2) != 0,
+        byte & (1 << 3) != 0,
+        byte & (1 << 4) != 0,
+        byte & (1 << 5) != 0,
+        byte & (1 << 6) != 0,
+        byte & (1 << 7) != 0,
+    ]
+}
+
+fn bitslice_to_usize(bitslice: [bool; 11]) -> usize {
+    usize::from(bitslice[0])
+        + (usize::from(bitslice[1]) << 1)
+        + (usize::from(bitslice[2]) << 2)
+        + (usize::from(bitslice[3]) << 3)
+        + (usize::from(bitslice[4]) << 4)
+        + (usize::from(bitslice[5]) << 5)
+        + (usize::from(bitslice[6]) << 6)
+        + (usize::from(bitslice[7]) << 7)
+        + (usize::from(bitslice[8]) << 8)
+        + (usize::from(bitslice[9]) << 9)
+        + (usize::from(bitslice[10]) << 10)
+}
+
 fn main() -> Result<(), Box<dyn Error>> {
     if !env::vars()
         .any(|(name, _)| name == "SHOOT_SELF_IN_FOOT" || name == "INSECURE_HARDWARE_ALLOWED")
@@ -105,35 +133,11 @@ fn main() -> Result<(), Box<dyn Error>> {
     let checksum = &hash[..bit_size / 32 / 8];
 
     let seed = [&entropy[..bit_size / 8], checksum].concat();
-    let seed_bits = seed
+    let seed_bits = seed.iter().flat_map(u8_to_bitslice).collect::<Vec<_>>();
-        .iter()
+    let words = seed_bits
-        .flat_map(|byte| {
+        .chunks_exact(11)
-            [
+        .map(|chunk| wordlist[bitslice_to_usize(chunk.try_into().expect("11 bit chunks"))].clone())
-                byte & (1 << 0) != 0,
-                byte & (1 << 1) != 0,
-                byte & (1 << 2) != 0,
-                byte & (1 << 3) != 0,
-                byte & (1 << 4) != 0,
-                byte & (1 << 5) != 0,
-                byte & (1 << 6) != 0,
-                byte & (1 << 7) != 0,
-            ]
-        })
         .collect::<Vec<_>>();
-    let words = seed_bits.chunks_exact(11).map(|chunk| {
-        let index = usize::from(chunk[0])
-            + (usize::from(chunk[1]) << 1)
-            + (usize::from(chunk[2]) << 2)
-            + (usize::from(chunk[3]) << 3)
-            + (usize::from(chunk[4]) << 4)
-            + (usize::from(chunk[5]) << 5)
-            + (usize::from(chunk[6]) << 6)
-            + (usize::from(chunk[7]) << 7)
-            + (usize::from(chunk[8]) << 8)
-            + (usize::from(chunk[9]) << 9)
-            + (usize::from(chunk[10]) << 10);
-        wordlist[index].clone()
-    }).collect::<Vec<_>>();
     println!("{}", words.join(" "));
 
     Ok(())