Release v0.3.0

vendor/github.com/lightningnetwork/lnd/shachain/utils.go

@@ -0,0 +1,74 @@
+package shachain
+
+import (
+	"encoding/hex"
+
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+)
+
+// getBit return bit on index at position.
+func getBit(index index, position uint8) uint8 {
+	return uint8((uint64(index) >> position) & 1)
+}
+
+func getPrefix(index index, position uint8) uint64 {
+	//	+ -------------------------- +
+	// 	| №  | value | mask | return |
+	//	+ -- + ----- + ---- + ------ +
+	//	| 63 |	 1   |  0   |	 0   |
+	//	| 62 |	 0   |  0   |	 0   |
+	//	| 61 |   1   |  0   |	 0   |
+	//		....
+	//	|  4 |	 1   |  0   |	 0   |
+	//	|  3 |   1   |  0   |	 0   |
+	//	|  2 |   1   |  1   |	 1   | <--- position
+	//	|  1 |   0   |  1   |	 0   |
+	//	|  0 |   1   |  1   |	 1   |
+	//	+ -- + ----- + ---- + ------ +
+
+	var zero uint64
+	mask := (zero - 1) - uint64((1<<position)-1)
+	return (uint64(index) & mask)
+}
+
+// countTrailingZeros counts number of trailing zero bits, this function is
+// used to determine the number of element bucket.
+func countTrailingZeros(index index) uint8 {
+	var zeros uint8
+	for ; zeros < maxHeight; zeros++ {
+
+		if getBit(index, zeros) != 0 {
+			break
+		}
+	}
+
+	return zeros
+}
+
+// hashFromString takes a hex-encoded string as input and creates an instance of
+// chainhash.Hash. The chainhash.NewHashFromStr function not suitable because
+// it reverse the given hash.
+func hashFromString(s string) (*chainhash.Hash, error) {
+	// Return an error if hash string is too long.
+	if len(s) > chainhash.MaxHashStringSize {
+		return nil, chainhash.ErrHashStrSize
+	}
+
+	// Hex decoder expects the hash to be a multiple of two.
+	if len(s)%2 != 0 {
+		s = "0" + s
+	}
+
+	// Convert string hash to bytes.
+	buf, err := hex.DecodeString(s)
+	if err != nil {
+		return nil, err
+	}
+
+	hash, err := chainhash.NewHash(buf)
+	if err != nil {
+		return nil, err
+	}
+
+	return hash, nil
+}