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vendor/github.com/RoaringBitmap/roaring/setutil_generic.go

@@ -0,0 +1,64 @@
+//go:build !arm64 || gccgo || appengine
+// +build !arm64 gccgo appengine
+
+package roaring
+
+func union2by2(set1 []uint16, set2 []uint16, buffer []uint16) int {
+	pos := 0
+	k1 := 0
+	k2 := 0
+	if 0 == len(set2) {
+		buffer = buffer[:len(set1)]
+		copy(buffer, set1[:])
+		return len(set1)
+	}
+	if 0 == len(set1) {
+		buffer = buffer[:len(set2)]
+		copy(buffer, set2[:])
+		return len(set2)
+	}
+	s1 := set1[k1]
+	s2 := set2[k2]
+	buffer = buffer[:cap(buffer)]
+	for {
+		if s1 < s2 {
+			buffer[pos] = s1
+			pos++
+			k1++
+			if k1 >= len(set1) {
+				copy(buffer[pos:], set2[k2:])
+				pos += len(set2) - k2
+				break
+			}
+			s1 = set1[k1]
+		} else if s1 == s2 {
+			buffer[pos] = s1
+			pos++
+			k1++
+			k2++
+			if k1 >= len(set1) {
+				copy(buffer[pos:], set2[k2:])
+				pos += len(set2) - k2
+				break
+			}
+			if k2 >= len(set2) {
+				copy(buffer[pos:], set1[k1:])
+				pos += len(set1) - k1
+				break
+			}
+			s1 = set1[k1]
+			s2 = set2[k2]
+		} else { // if (set1[k1]>set2[k2])
+			buffer[pos] = s2
+			pos++
+			k2++
+			if k2 >= len(set2) {
+				copy(buffer[pos:], set1[k1:])
+				pos += len(set1) - k1
+				break
+			}
+			s2 = set2[k2]
+		}
+	}
+	return pos
+}