Merge pull request from GitHub pr175

src/sql/engine/expr/ob_expr_export_set.h

@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) 2021 OceanBase
+ * OceanBase CE is licensed under Mulan PubL v2.
+ * You can use this software according to the terms and conditions of the Mulan PubL v2.
+ * You may obtain a copy of Mulan PubL v2 at:
+ *          http://license.coscl.org.cn/MulanPubL-2.0
+ * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+ * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+ * See the Mulan PubL v2 for more details.
+ */
+
+#ifndef OCEANBASE_SQL_ENGINE_EXPR_OB_EXPR_EXPORT_SET_
+#define OCEANBASE_SQL_ENGINE_EXPR_OB_EXPR_EXPORT_SET_
+
+#include "sql/engine/expr/ob_expr_operator.h"
+
+namespace oceanbase {
+namespace sql {
+class ObExprExportSet : public ObStringExprOperator {
+public:
+  explicit ObExprExportSet(common::ObIAllocator& alloc);
+  virtual ~ObExprExportSet();
+  virtual int calc_result_typeN(
+      ObExprResType& type, ObExprResType* types_array, int64_t param_num, common::ObExprTypeCtx& type_ctx) const;
+  virtual int calc_resultN(
+      common::ObObj& result, const common::ObObj* objs_array, int64_t param_num, common::ObExprCtx& expr_ctx) const;
+  virtual int calc_export_set(common::ObObj& result, const common::ObObj& bits, const common::ObObj& on,
+      const common::ObObj& off, const common::ObObj& sep, const common::ObObj& n_bits, common::ObExprCtx& expr_ctx) const;
+  virtual int cg_expr(ObExprCGCtx& op_cg_ctx, const ObRawExpr& raw_expr, ObExpr& rt_expr) const override;
+  static int eval_export_set(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& expr_datum);
+private:
+  // disallow copy
+  DISALLOW_COPY_AND_ASSIGN(ObExprExportSet);
+  // helper func
+  static int calc_export_set_inner(ObString& ret_str, const uint64_t bits, const ObString& on, const ObString& off,
+    const ObString& sep, const int64_t n_bits, ObExprStringBuf& string_buf);
+};
+}  // namespace sql
+}  // namespace oceanbase
+
+#endif  // OCEANBASE_SQL_ENGINE_EXPR_OB_EXPR_EXPORT_SET_