1 files changed, 61 insertions, 0 deletions
diff --git a/src/helpers.rs b/src/helpers.rs
new file mode 100644
index 0000000..32f0e25
--- /dev/null
+++ b/src/helpers.rs
@@ -0,0 +1,61 @@
+
+use errors::*;
+use crypto::digest::Digest;
+use crypto::blake2b::Blake2b;
+
+/// Helper to calculate a discovery key from a public key. 'key' should be 32 bytes; the returned
+/// array will also be 32 bytes long.
+///
+/// dat discovery keys are calculated as a BLAKE2b "keyed hash" (using the passed key) of the string
+/// "hypercore" (with no trailing null byte).
+pub fn make_discovery_key(key: &[u8]) -> Vec<u8> {
+    let mut discovery_key = [0; 32];
+    let mut hash = Blake2b::new_keyed(32, key);
+    hash.input(&"hypercore".as_bytes());
+    hash.result(&mut discovery_key);
+    discovery_key.to_vec()
+}
+
+/// Helper to parse a dat address (aka, public key) in string format.
+///
+/// Address can start with 'dat://'. It should contain 64 hexadecimal characters.
+pub fn parse_dat_address(input: &str) -> Result<Vec<u8>> {
+
+    let raw_key = if input.starts_with("dat://") {
+        &input[6..]
+    } else {
+        input
+    };
+    if raw_key.len() != 32 * 2 {
+        bail!("dat key not correct length");
+    }
+    let mut key_bytes = vec![];
+    for i in 0..32 {
+        let r = u8::from_str_radix(&raw_key[2 * i..2 * i + 2], 16);
+        match r {
+            Ok(b) => key_bytes.push(b),
+            Err(e) => bail!("Problem with hex: {}", e),
+        };
+    }
+    Ok(key_bytes)
+}
+
+#[test]
+fn test_parse_dat_address() {
+
+    assert!(parse_dat_address(
+        "c7638882870abd4044d6467b0738f15e3a36f57c3a7f7f3417fd7e4e0841d597").is_ok());
+    assert!(parse_dat_address(
+        "C7638882870ABD4044D6467B0738F15E3A36F57C3A7F7F3417FD7E4E0841D597").is_ok());
+    assert!(parse_dat_address(
+        "dat://c7638882870abd4044d6467b0738f15e3a36f57c3a7f7f3417fd7e4e0841d597").is_ok());
+
+    assert!(parse_dat_address(
+        "c7638882870ab").is_err());
+    assert!(parse_dat_address(
+        "g7638882870abd4044d6467b0738f15e3a36f57c3a7f7f3417fd7e4e0841d597").is_err());
+    assert!(parse_dat_address(
+        "dat://c7638882870abd4044d6467b0738f15e3a36f57c3a7f7f3417fd7e4e0841d5970").is_err());
+    assert!(parse_dat_address(
+        "dat://c7638882870abd4044d6467b0738f15e3a36f57c3a7f7f3417fd7e4e0841d59").is_err());
+}