core, eth: add bloombit indexer, filter based on it

1 files changed, 14 insertions, 0 deletions

diff --git a/core/types/bloom9.go b/core/types/bloom9.go
index 60aacc301..bdc6e60e7 100644
--- a/core/types/bloom9.go
+++ b/core/types/bloom9.go
@@ -106,6 +106,20 @@ func LogsBloom(logs []*Log) *big.Int {
 	return bin
 }
 
+type BloomIndexList [3]uint
+
+// BloomIndexes returns the bloom filter bit indexes belonging to the given key
+func BloomIndexes(b []byte) BloomIndexList {
+	b = crypto.Keccak256(b[:])
+
+	var r [3]uint
+	for i, _ := range r {
+		r[i] = (uint(b[i+i+1]) + (uint(b[i+i]) << 8)) & 2047
+	}
+
+	return r
+}
+
 func bloom9(b []byte) *big.Int {
 	b = crypto.Keccak256(b[:])