From 4848a99acaf1e7cd5db2c7c9f6cddda01deac4c1 Mon Sep 17 00:00:00 2001
From: Matt Jaffee <jaffee@umbel.com>
Date: Tue, 30 May 2017 13:19:02 -0500
Subject: [PATCH] unionRunRun working - messy

---
 roaring/roaring.go               | 66 +++++++++++++++++++++++++++++++-
 roaring/roaring_internal_test.go | 35 +++++++++++++++++
 2 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/roaring/roaring.go b/roaring/roaring.go
index 729cf3ec4..201e2be21 100644
--- a/roaring/roaring.go
+++ b/roaring/roaring.go
@@ -1865,7 +1865,71 @@ func unionArrayRun(a, b *container) *container {
 }
 
 func unionRunRun(a, b *container) *container {
-	return nil
+	na, nb := len(a.runs), len(b.runs)
+	if na == 0 {
+		return b.clone()
+	} else if nb == 0 {
+		return a.clone()
+	}
+	output := &container{
+		runs: make([]interval32, 0, na+nb),
+	}
+	i, j := 0, 0
+	if a.runs[0].start < b.runs[0].start {
+		output.runs = append(output.runs, a.runs[0])
+		i = 1
+	} else {
+		output.runs = append(output.runs, b.runs[0])
+		j = 1
+	}
+	for i < na && j < nb {
+		va, vb := a.runs[i], b.runs[j]
+		lastrun := output.runs[len(output.runs)-1]
+		if va.start < vb.start {
+			if va.start <= lastrun.last+1 {
+				if lastrun.last < va.last {
+					lastrun.last = va.last
+					output.runs[len(output.runs)-1] = lastrun
+				}
+			} else {
+				output.runs = append(output.runs, va)
+			}
+			i++
+		} else {
+			if vb.start <= lastrun.last+1 {
+				if lastrun.last < vb.last {
+					lastrun.last = vb.last
+					output.runs[len(output.runs)-1] = lastrun
+				}
+			} else {
+				output.runs = append(output.runs, vb)
+			}
+			j++
+		}
+	}
+	var k int
+	var rest []interval32
+	if i < na {
+		k = i
+		rest = a.runs
+	} else {
+		k = j
+		rest = b.runs
+	}
+	for k < len(rest) {
+		vk := rest[k]
+		lastrun := output.runs[len(output.runs)-1]
+		if vk.start <= lastrun.last+1 {
+			if lastrun.last < vk.last {
+				lastrun.last = vk.last
+				output.runs[len(output.runs)-1] = lastrun
+			}
+		} else {
+			output.runs = append(output.runs, vk)
+		}
+		k++
+	}
+	return output
 }
 
 func unionBitmapRun(a, b *container) *container {
diff --git a/roaring/roaring_internal_test.go b/roaring/roaring_internal_test.go
index 91e256e05..0231bf93f 100644
--- a/roaring/roaring_internal_test.go
+++ b/roaring/roaring_internal_test.go
@@ -525,3 +525,38 @@ func TestIntersectBitmapRunArray(t *testing.T) {
 	}
 
 }
+
+func TestUnionRunRun(t *testing.T) {
+	a := &container{}
+	b := &container{}
+	tests := []struct {
+		aruns []interval32
+		bruns []interval32
+		exp   []interval32
+	}{
+		{
+			aruns: []interval32{},
+			bruns: []interval32{{start: 5, last: 10}},
+			exp:   []interval32{{start: 5, last: 10}},
+		},
+		{
+			aruns: []interval32{{start: 5, last: 12}},
+			bruns: []interval32{{start: 5, last: 10}},
+			exp:   []interval32{{start: 5, last: 12}},
+		},
+		{
+			aruns: []interval32{{start: 1, last: 3}, {start: 5, last: 5}, {start: 7, last: 8}, {start: 9, last: 12}},
+			bruns: []interval32{{start: 5, last: 10}},
+			exp:   []interval32{{start: 1, last: 3}, {start: 5, last: 12}},
+		},
+	}
+	for i, test := range tests {
+		a.runs = test.aruns
+		b.runs = test.bruns
+		ret := unionRunRun(a, b)
+		if !reflect.DeepEqual(ret.runs, test.exp) {
+			t.Fatalf("test #%v expected %v, but got %v", i, test.exp, ret.runs)
+		}
+	}
+
+}