Initial QSfera import

Server/vendor/github.com/RoaringBitmap/roaring/v2/clz.go

@@ -0,0 +1,19 @@
+//go:build go1.9
+// +build go1.9
+
+// "go1.9", from Go version 1.9 onward
+// See https://golang.org/pkg/go/build/#hdr-Build_Constraints
+
+package roaring
+
+import "math/bits"
+
+// countLeadingOnes returns the number of leading zeros bits in x; the result is 64 for x == 0.
+func countLeadingZeros(x uint64) int {
+	return bits.LeadingZeros64(x)
+}
+
+// countLeadingOnes returns the number of leading ones bits in x; the result is 0 for x == 0.
+func countLeadingOnes(x uint64) int {
+	return bits.LeadingZeros64(^x)
+}