Add key lookup support for tables in Go (#7644)

* Add support for key lookup for tables in Go

* Run clang format

* Run go fmt on tests

* Remove TODO in tests

* Update LookupByKey API

* Update LookupByKey API

* Don't use resolvePointer in expectEq

* Use generated getters instead of reading values directly from buffer

* Fix typo

Co-authored-by: Derek Bailey <derekbailey@google.com>

tests/MyGame/Example/Referrable.go

@@ -67,6 +67,43 @@ func (rcv *Referrable) MutateId(n uint64) bool {
 	return rcv._tab.MutateUint64Slot(4, n)
 }
 
+func ReferrableKeyCompare(o1, o2 flatbuffers.UOffsetT, buf []byte) bool {
+	obj1 := &Referrable{}
+	obj2 := &Referrable{}
+	obj1.Init(buf, flatbuffers.UOffsetT(len(buf)) - o1)
+	obj2.Init(buf, flatbuffers.UOffsetT(len(buf)) - o2)
+	return obj1.Id() < obj2.Id()
+}
+
+func (rcv *Referrable) LookupByKey(key uint64, vectorLocation flatbuffers.UOffsetT, buf []byte) bool {
+	span := flatbuffers.GetUOffsetT(buf[vectorLocation - 4:])
+	start := flatbuffers.UOffsetT(0)
+	for span != 0 {
+		middle := span / 2
+		tableOffset := flatbuffers.GetIndirectOffset(buf, vectorLocation+ 4 * (start + middle))
+		obj := &Referrable{}
+		obj.Init(buf, tableOffset)
+		val := obj.Id()
+		comp := 0
+		if val > key {
+			comp = 1
+		} else if val < key {
+			comp = -1
+		}
+		if comp > 0 {
+			span = middle
+		} else if comp < 0 {
+			middle += 1
+			start += middle
+			span -= middle
+		} else {
+			rcv.Init(buf, tableOffset)
+			return true
+		}
+	}
+	return false
+}
+
 func ReferrableStart(builder *flatbuffers.Builder) {
 	builder.StartObject(1)
 }