implement expr asin/acos/cot/cos in mysql mode

src/sql/engine/expr/ob_expr_cot.cpp

@@ -0,0 +1,70 @@
+/**
+ * Copyright 2014-2016 Alibaba Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ *
+ * Authors:
+ *     zimiao<kaizhan.dkz@antgroup.com>
+ */
+#define USING_LOG_PREFIX SQL_ENG
+#include "sql/parser/ob_item_type.h"
+#include "lib/oblog/ob_log.h"
+#include "lib/number/ob_number_v2.h"
+#include "sql/engine/expr/ob_expr_cot.h"
+#include "sql/session/ob_sql_session_info.h"
+#include <math.h>
+namespace oceanbase
+{
+using namespace common;
+using namespace common::number;
+namespace sql
+{
+ObExprCot::ObExprCot(ObIAllocator &alloc)
+    : ObFuncExprOperator(alloc, T_FUN_SYS_COT, N_COT, 1, NOT_ROW_DIMENSION)
+{
+}
+ObExprCot::~ObExprCot()
+{
+}
+int ObExprCot::calc_result_type1(ObExprResType &type,
+                                 ObExprResType &radian,
+                                 ObExprTypeCtx &type_ctx) const
+{
+  return calc_trig_function_result_type1(type, radian, type_ctx);
+}
+int ObExprCot::calc_result1(ObObj &result,
+                            const ObObj &radian_obj,
+                            ObExprCtx &expr_ctx) const
+{
+  int ret = OB_SUCCESS;
+  if (radian_obj.is_null()) {
+    result.set_null();
+  } else if (OB_ISNULL(expr_ctx.calc_buf_)) {
+    ret = OB_NOT_INIT;
+    LOG_WARN("expr_ctx.calc_buf_ is NULL", K(ret));
+  } else if (radian_obj.is_double()) {
+    double arg = radian_obj.get_double();
+    double tan_out = tan(arg);
+    // to check tan(arg) is small enough to be zero
+    if (0.0 == tan_out) {
+      ret = OB_INVALID_ARGUMENT;
+      LOG_WARN("tan(x) is zero", K(ret));
+    } else {
+      double res = 1.0/tan_out;
+      if (!std::isfinite(res)) {
+        ret = OB_INVALID_ARGUMENT;
+        LOG_WARN("tan(x) is like zero", K(ret));
+      } else {
+        result.set_double(res);
+      }
+    }
+  } else {
+    ret = OB_ERR_UNEXPECTED;
+  }
+  return ret;
+}
+} /* sql */
+} /* oceanbase */