SQL select query for CSV/JSON (#6648)

select * , select column names have been implemented for CSV.
select * is implemented for JSON.

pkg/s3select/format/helpers.go

@@ -0,0 +1,50 @@
+/*
+ * Minio Cloud Storage, (C) 2018 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package format
+
+import "strconv"
+
+// IsInt - returns a true or false, whether a string can
+// be represented as an int.
+func IsInt(s string) bool {
+	_, err := strconv.Atoi(s)
+	return err == nil
+}
+
+// StringInSlice - this function finds whether a string is in a list
+func StringInSlice(x string, list []string) bool {
+	for _, y := range list {
+		if x == y {
+			return true
+		}
+	}
+	return false
+}
+
+// ProcessSize - this function processes size so that we can calculate bytes BytesProcessed.
+func ProcessSize(myrecord []string) int64 {
+	if len(myrecord) > 0 {
+		var size int64
+		size = int64(len(myrecord)-1) + 1
+		for i := range myrecord {
+			size += int64(len(myrecord[i]))
+		}
+
+		return size
+	}
+	return 0
+}