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oceanbase/src/sql/engine/expr/ob_expr_util.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 _OB_ENGINE_EXPR_EXPR_UTIL_H_
#define _OB_ENGINE_EXPR_EXPR_UTIL_H_
#include "lib/number/ob_number_v2.h"
#include "sql/engine/expr/ob_expr_operator.h"
namespace oceanbase {
namespace sql {
//
// temporary allocator for number operation. e.g.:
// ObNumStackAllocator num_alloc;
// number::ObNumber num;
// num.from(int_val, num_alloc);
// expr_datum.set_number(num); // set_datum will deep copy num value.
//
template <int64_t NUM_CNT = 1>
class ObNumStackAllocator : public common::ObDataBuffer {
public:
ObNumStackAllocator() : ObDataBuffer(local_buf_, sizeof(local_buf_))
{}
private:
char local_buf_[NUM_CNT * common::number::ObNumber::MAX_BYTE_LEN];
};
typedef ObNumStackAllocator<1> ObNumStackOnceAlloc;
#define array_elements(A) ((uint)(sizeof(A) / sizeof(A[0])))
class ObExprUtil {
public:
static int get_trunc_int64(const common::ObObj& obj, common::ObExprCtx& expr_ctx, int64_t& out);
static int get_round_int64(const common::ObObj& obj, common::ObExprCtx& expr_ctx, int64_t& out);
static int get_trunc_int64(common::number::ObNumber& nmb, common::ObExprCtx& expr_ctx, int64_t& out);
static int get_round_int64(common::number::ObNumber& nmb, common::ObExprCtx& expr_ctx, int64_t& out);
static int kmp_reverse(const char* x, int64_t m, const char* y, int64_t n, int64_t count, int64_t& pos);
static int kmp(const char* x, int64_t m, const char* y, int64_t n, int64_t count, int64_t& pos);
static int get_mb_str_info(const common::ObString& str, common::ObCollationType cs_type,
common::ObIArray<size_t>& byte_num, common::ObIArray<size_t>& byte_offset);
static double round_double(double val, int64_t dec);
static double round_double_nearest(double val, int64_t dec);
static uint64_t round_uint64(uint64_t val, int64_t dec);
static double trunc_double(double val, int64_t dec);
template <typename T>
static T trunc_integer(T val, int64_t dec);
// truncate the decimal part, truncate to INT64_MAX/INT64_MIN too if out of range.
static int trunc_num2int64(const common::number::ObNumber& nmb, int64_t& v);
// get number out of ObDatum and truncate to int64
static int trunc_num2int64(const common::ObDatum& datum, int64_t& v)
{
return trunc_num2int64(common::number::ObNumber(datum.get_number()), v);
}
// Get integer value from integer parameter which type is ObIntType in mysql
// or ObNumberType in oracle.
//
// Keep %int_val unchanged if datum is NULL or datum->is_null().
static int get_int_param_val(common::ObDatum* datum, int64_t& int_val);
// Set the ASCII string to expression result.
// e.g.:
// dump() need result is NLS_CHARACTERSET, but we can only generate ASCII string in code,
// this function is used to convert the result characterset.
static int set_expr_ascii_result(
const ObExpr& expr, ObEvalCtx& ctx, common::ObDatum& expr_datum, const common::ObString& ascii_str);
static int convert_string_collation(const common::ObString& in_str, const common::ObCollationType& in_collation,
common::ObString& out_str, const common::ObCollationType& out_collation, common::ObIAllocator& alloc);
static int need_convert_string_collation(
const common::ObCollationType& in_collation, const common::ObCollationType& out_collation, bool& need_convert);
// deep copy src to out.
// it is ok if src and out is same. like this deep_copy_str(str1, str1, alloc)
static int deep_copy_str(const common::ObString& src, common::ObString& out, common::ObIAllocator& alloc);
static int eval_generated_column(const ObExpr& rt_expr, ObEvalCtx& ctx, ObDatum& expr_datum);
static int eval_stack_overflow_check(const ObExpr& rt_expr, ObEvalCtx& ctx, ObDatum& expr_datum);
private:
static int get_int64_from_num(common::number::ObNumber& nmb, common::ObExprCtx& expr_ctx,
const bool is_trunc, // true: trunc; false: round
int64_t& out);
static int get_int64_from_obj(const common::ObObj& obj, common::ObExprCtx& expr_ctx,
const bool is_trunc, // true: trunc; false: round
int64_t& out);
DISALLOW_COPY_AND_ASSIGN(ObExprUtil);
};
// make sure T is int/uint type
template <typename T>
T ObExprUtil::trunc_integer(T val, int64_t dec)
{
volatile T res = 0;
if (dec >= 0) {
res = val;
} else {
const int64_t max_integer_desc = 19;
if (std::abs(dec) > max_integer_desc) {
res = 0;
} else {
const T pow_val = std::pow(10, static_cast<int64_t>(std::abs(dec)));
res = (val / pow_val) * pow_val;
}
}
return res;
}
// define triangle calc functions
// eg: sin/cos/tan sinh/cosh/tanh asin/acos/atan
// note: atan2 is defined elsewhere
#define DEF_CALC_TRIGONOMETRIC_EXPR(tritype, INVALID_DOUBLE_ARG_CHECK, INVALID_DOUBLE_ARG_ERRNO) \
int calc_##tritype##_expr(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& res_datum) \
{ \
int ret = OB_SUCCESS; \
ObDatum* radian = NULL; \
if (OB_FAIL(expr.args_[0]->eval(ctx, radian))) { \
LOG_WARN("eval radian arg failed", K(ret), K(expr)); \
} else if (radian->is_null()) { \
/* radian is already be cast to number type, no need to is_null_oracle */ \
res_datum.set_null(); \
} else if (ObNumberType == expr.args_[0]->datum_meta_.type_) { \
number::ObNumber res_nmb; \
number::ObNumber radian_nmb(radian->get_number()); \
if (OB_FAIL(radian_nmb.tritype(res_nmb, ctx.get_reset_tmp_alloc()))) { \
LOG_WARN("calc expr failed", K(ret), K(radian_nmb), K(expr)); \
} else { \
res_datum.set_number(res_nmb); \
} \
} else if (ObDoubleType == expr.args_[0]->datum_meta_.type_) { \
const double arg = radian->get_double(); \
if (INVALID_DOUBLE_ARG_CHECK) { \
res_datum.set_null(); \
} else { \
res_datum.set_double(tritype(arg)); \
} \
} else { \
ret = OB_ERR_UNEXPECTED; \
} \
return ret; \
}
} // namespace sql
} // namespace oceanbase
#endif /* _OB_ENGINE_EXPR_EXPR_UTIL_H_ */