Add KeyHasher based on CRC-32

crc32.go

@@ -0,0 +1,38 @@
+package jump
+
+import "hash"
+
+type crc32Hasher struct {
+	crc32 hash.Hash32
+}
+
+func (h *crc32Hasher) Write(p []byte) (n int, err error) {
+	return h.crc32.Write(p)
+}
+
+func (h *crc32Hasher) Sum(b []byte) []byte {
+	return h.crc32.Sum(b)
+}
+
+func (h *crc32Hasher) Reset() {
+	h.crc32.Reset()
+}
+
+func (h *crc32Hasher) Size() int {
+	return h.crc32.Size()
+}
+
+func (h *crc32Hasher) BlockSize() int {
+	return h.crc32.BlockSize()
+}
+
+func (h *crc32Hasher) Sum32() uint32 {
+	return h.crc32.Sum32()
+}
+
+func (h *crc32Hasher) Sum64() uint64 {
+	return uint64(h.crc32.Sum32())
+}
+
+var _ hash.Hash32 = (*crc32Hasher)(nil)
+var _ hash.Hash64 = (*crc32Hasher)(nil)