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src/sql/engine/expr/ob_expr_substring_index.h

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+/**
+ * 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_SUBSTRING_INDEX_
+#define OCEANBASE_SQL_ENGINE_EXPR_OB_EXPR_SUBSTRING_INDEX_
+
+#include "lib/container/ob_array.h"
+#include "sql/engine/expr/ob_expr_operator.h"
+
+namespace oceanbase {
+namespace sql {
+class ObExprSubstringIndex : public ObStringExprOperator {
+  public:
+  explicit ObExprSubstringIndex(common::ObIAllocator& alloc);
+  virtual ~ObExprSubstringIndex();
+  virtual int calc_result_type3(ObExprResType& type, ObExprResType& str, ObExprResType& delim, ObExprResType& count,
+      common::ObExprTypeCtx& type_ctx) const;
+  virtual int calc_result3(common::ObObj& result, const common::ObObj& str, const common::ObObj& delim,
+      const common::ObObj& count, 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_substring_index(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& expr_datum);
+
+  private:
+  /**
+   * find m_count apperance of m_delim in m_str(from left or from right)
+   * @param[in] result      calculated result
+   * parma[in] m_str        string
+   * @param[in] m_delim     substring
+   * @param[in] m_count     nth apperance
+   * @return                position of nth apperance of delim
+   */
+  static int string_search(
+      common::ObString& result, const common::ObString& m_str, const common::ObString& m_delim, const int64_t m_count);
+
+  private:
+  DISALLOW_COPY_AND_ASSIGN(ObExprSubstringIndex);
+};
+
+}  // namespace sql
+}  // namespace oceanbase
+
+#endif  // OCEANBASE_SQL_ENGINE_EXPR_OB_EXPR_SUBSTRING_INDEX_