add vendoring with go dep

vendor/github.com/influxdata/influxdb/influxql/iterator_mapper.go

@@ -0,0 +1,44 @@
+package influxql
+
+import "fmt"
+
+type IteratorMap interface {
+	Value(tags Tags, buf []interface{}) interface{}
+}
+
+type FieldMap int
+
+func (i FieldMap) Value(tags Tags, buf []interface{}) interface{} { return buf[i] }
+
+type TagMap string
+
+func (s TagMap) Value(tags Tags, buf []interface{}) interface{} { return tags.Value(string(s)) }
+
+type NullMap struct{}
+
+func (NullMap) Value(tags Tags, buf []interface{}) interface{} { return nil }
+
+func NewIteratorMapper(itrs []Iterator, driver IteratorMap, fields []IteratorMap, opt IteratorOptions) Iterator {
+	if driver != nil {
+		switch driver := driver.(type) {
+		case FieldMap:
+			switch itrs[int(driver)].(type) {
+			case FloatIterator:
+				return newFloatIteratorMapper(itrs, driver, fields, opt)
+			case IntegerIterator:
+				return newIntegerIteratorMapper(itrs, driver, fields, opt)
+			case StringIterator:
+				return newStringIteratorMapper(itrs, driver, fields, opt)
+			case BooleanIterator:
+				return newBooleanIteratorMapper(itrs, driver, fields, opt)
+			default:
+				panic(fmt.Sprintf("unable to map iterator type: %T", itrs[int(driver)]))
+			}
+		case TagMap:
+			return newStringIteratorMapper(itrs, driver, fields, opt)
+		default:
+			panic(fmt.Sprintf("unable to create iterator mapper with driveression type: %T", driver))
+		}
+	}
+	return newFloatIteratorMapper(itrs, nil, fields, opt)
+}