Add subcrate which impls a simple SPV client from Bitcoin Core RPC

[rust-lightning] / lightning-block-sync / src / utils.rs

diff --git a/lightning-block-sync/src/utils.rs b/lightning-block-sync/src/utils.rs
new file mode 100644 (file)
index 0000000..90c97b5
--- /dev/null
+++ b/lightning-block-sync/src/utils.rs
@@ -0,0 +1,44 @@
+use bitcoin::util::uint::Uint256;
+
+pub fn hex_to_uint256(hex: &str) -> Option<Uint256> {
+       if hex.len() != 64 { return None; }
+       let mut out = [0u64; 4];
+
+       let mut b: u64 = 0;
+       for (idx, c) in hex.as_bytes().iter().enumerate() {
+               b <<= 4;
+               match *c {
+                       b'A'..=b'F' => b |= (c - b'A' + 10) as u64,
+                       b'a'..=b'f' => b |= (c - b'a' + 10) as u64,
+                       b'0'..=b'9' => b |= (c - b'0') as u64,
+                       _ => return None,
+               }
+               if idx % 16 == 15 {
+                       out[3 - (idx / 16)] = b;
+                       b = 0;
+               }
+       }
+       Some(Uint256::from(&out[..]))
+}
+
+#[cfg(feature = "rpc-client")]
+pub fn hex_to_vec(hex: &str) -> Option<Vec<u8>> {
+       let mut out = Vec::with_capacity(hex.len() / 2);
+
+       let mut b = 0;
+       for (idx, c) in hex.as_bytes().iter().enumerate() {
+               b <<= 4;
+               match *c {
+                       b'A'..=b'F' => b |= c - b'A' + 10,
+                       b'a'..=b'f' => b |= c - b'a' + 10,
+                       b'0'..=b'9' => b |= c - b'0',
+                       _ => return None,
+               }
+               if (idx & 1) == 1 {
+                       out.push(b);
+                       b = 0;
+               }
+       }
+
+       Some(out)
+}