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oceanbase/src/sql/engine/expr/ob_expr_weight_string.cpp
2023-04-27 11:11:24 +00:00

250 lines
9.8 KiB
C++

/**
* 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.
*/
#define USING_LOG_PREFIX SQL_ENG
#define OB_MAX_WEIGHT OB_MAX_VARCHAR_LENGTH
#include <string.h>
#include "objit/common/ob_item_type.h"
#include "sql/engine/expr/ob_expr_weight_string.h"
#include "sql/engine/expr/ob_expr_operator.h"
#include "share/object/ob_obj_cast.h"
#include "lib/oblog/ob_log.h"
#include "sql/engine/expr/ob_datum_cast.h"
#include "ob_expr_util.h"
#include "sql/engine/ob_exec_context.h"
#include "sql/session/ob_sql_session_info.h"
using namespace oceanbase::common;
namespace oceanbase
{
namespace sql
{
ObExprWeightString::ObExprWeightString(ObIAllocator &alloc)
: ObStringExprOperator(alloc, T_FUN_SYS_WEIGHT_STRING, N_WEIGHT_STRING, MORE_THAN_ZERO, NOT_VALID_FOR_GENERATED_COL)
{
}
ObExprWeightString::~ObExprWeightString()
{
}
int ObExprWeightString::calc_result_typeN(ObExprResType &type,
ObExprResType *types_stack,
int64_t param_num,
ObExprTypeCtx &type_ctx) const
{
int ret = OB_SUCCESS;
UNUSED(param_num);
CK (OB_NOT_NULL(type_ctx.get_session()));
if (NOT_ROW_DIMENSION != row_dimension_ || ObMaxType == types_stack[0].get_type()) {
ret = OB_ERR_INVALID_TYPE_FOR_OP;
} else {
uint64_t max_length = OB_MAX_VARBINARY_LENGTH; // The maximum length of the result of WEIGHT_STRING()
uint64_t result_length = types_stack[1].get_param().get_int();
uint64_t nweight = types_stack[2].get_param().get_int();
bool as_binary = types_stack[4].get_param().get_int();
ObCollationLevel coll_level = CS_LEVEL_INVALID;
if (as_binary) {
coll_level = CS_LEVEL_IMPLICIT;
type_ctx.set_cast_mode(type_ctx.get_cast_mode() | CM_NULL_ON_WARN);
types_stack[0].set_calc_type(ObVarcharType);
} else {
coll_level = types_stack[0].get_collation_level();
if (types_stack[0].get_type() > ObUNumberType &&
types_stack[0].get_type() != ObBitType &&
types_stack[0].get_type() != ObYearType) {
// When the input is not a numeric type, convert to a varchar type
type_ctx.set_cast_mode(type_ctx.get_cast_mode() | CM_NULL_ON_WARN);
types_stack[0].set_calc_type(ObVarcharType);
}
}
ObCollationType collation_type = types_stack[0].get_collation_type();
const ObCharsetInfo *cs = ObCharset::get_charset(collation_type);
if (types_stack[0].get_type() == ObDateTimeType ||
types_stack[0].get_type() == ObTimestampType ||
types_stack[0].get_type() == ObDateType ||
types_stack[0].get_type() == ObTimeType ) {
// For types such as date, time, etc., the max_lenght is the length of the type entered
max_length = types_stack[0].get_length();
} else if (result_length > 0) {
max_length = result_length;
} else if (as_binary) {
// In the case of as_binary, the max_length with nweight as the output result
max_length = nweight;
} else {
// If the input is others, use cs->mbmaxlen to calculate the max_length
max_length = cs->mbmaxlen * MAX(nweight, types_stack[0].get_length()*cs->mbmaxlen);
}
type.set_varchar();
type.set_collation_type(CS_TYPE_BINARY);
type.set_collation_level(coll_level);
type.set_length(max_length);
}
return ret;
}
int ObExprWeightString::eval_weight_string(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res_datum)
{
int ret = OB_SUCCESS;
ObDatum *arg = NULL;
ObDatum *result_length_arg = NULL;
ObDatum *nweights_arg = NULL;
ObDatum *flags_arg = NULL;
ObDatum *as_binary_arg = NULL;
if (OB_FAIL(expr.args_[0]->eval(ctx, arg)) ||
OB_FAIL(expr.args_[1]->eval(ctx, result_length_arg)) ||
OB_FAIL(expr.args_[2]->eval(ctx, nweights_arg)) ||
OB_FAIL(expr.args_[3]->eval(ctx, flags_arg)) ||
OB_FAIL(expr.args_[4]->eval(ctx, as_binary_arg))) {
LOG_WARN("eval arg failed", K(ret),
KP(arg),
KP(result_length_arg),
KP(nweights_arg),
KP(flags_arg),
KP(as_binary_arg));
} else {
const ObString str = arg->get_string();
uint64_t result_length = result_length_arg->get_int();
uint64_t nweights = nweights_arg->get_int();
uint64_t flags = flags_arg->get_int();
bool as_binary = as_binary_arg->get_int();
int64_t max_allowed_packet = 0;
ObSQLSessionInfo *session = ctx.exec_ctx_.get_my_session();
if (arg->is_null()) {
res_datum.set_null();
} else if (!as_binary && (expr.args_[0]->datum_meta_.type_ <= ObUNumberType ||
expr.args_[0]->datum_meta_.type_ == ObBitType ||
expr.args_[0]->datum_meta_.type_ == ObYearType)) {
res_datum.set_null();
} else if (arg->get_string().empty() && nweights == 0) {
res_datum.set_string(nullptr,0);
} else {
if (OB_FAIL(session->get_max_allowed_packet(max_allowed_packet))) {
if (OB_ENTRY_NOT_EXIST == ret) {
ret = OB_SUCCESS;
max_allowed_packet = OB_MAX_VARCHAR_LENGTH;
} else {
LOG_WARN("Failed to get max allow packet size", K(ret));
}
}
// Get the character set and collation information of the input string
ObCollationType collation_type = CS_TYPE_INVALID;
if (as_binary) {
collation_type = CS_TYPE_BINARY;
} else {
collation_type = expr.args_[0]->datum_meta_.cs_type_;
}
const ObCharsetInfo *cs = ObCharset::get_charset(collation_type);
flags = ob_strxfrm_flag_normalize(flags, cs->levels_for_order);
// calc the length of result
size_t frm_length = 0;
size_t tmp_length = 0;
if (result_length > 0) {
tmp_length = result_length;
} else {
tmp_length = cs->coll->strnxfrmlen(cs, cs->mbmaxlen*MAX(str.length() , nweights));
}
if (tmp_length >= max_allowed_packet) {
// The return result exceeds the maximum limit and returns NULL.
res_datum.set_null();
} else {
int used_nweights = nweights;
size_t input_length = str.length();
if (used_nweights) {
//truncate input string
input_length = std::min(input_length, cs->cset->charpos(cs, str.ptr(), str.ptr() + str.length(), nweights));
} else {
//calc char length
used_nweights = cs->cset->numchars(cs, str.ptr(), str.ptr() + str.length());
}
bool is_valid_unicode_tmp = 1;
char *out_buf = expr.get_str_res_mem(ctx, tmp_length);
// For the case where the input is an empty string but the nweight is not 0,
// the weight_string function will call strnxfrm() to padding the result
// eg:
// mysql> select HEX(WEIGHT_STRING('' as char(3)));
// +-----------------------------------+
// | HEX(WEIGHT_STRING('' as char(3))) |
// +-----------------------------------+
// | 002000200020 |
// +-----------------------------------+
// However, the strnxfrm requires that the input cannot be a null ptr,
// so an empty string is set as the input.
const char* tmp_empty_str = "";
if (OB_ISNULL(out_buf)) {
ret = OB_ALLOCATE_MEMORY_FAILED;
LOG_WARN("failed to alloc output buf",K(ret));
} else {
frm_length = cs->coll->strnxfrm(cs,
reinterpret_cast<uchar *>(out_buf),
tmp_length,
used_nweights,
str.ptr() != NULL? reinterpret_cast<const uchar *>(str.ptr()) : reinterpret_cast<const uchar *>(tmp_empty_str),
input_length,
flags,
&is_valid_unicode_tmp);
res_datum.set_string(out_buf,frm_length);
}
}
}
}
return ret;
}
int ObExprWeightString::cg_expr(ObExprCGCtx &op_cg_ctx, const ObRawExpr &raw_expr,
ObExpr &rt_expr) const
{
UNUSED(op_cg_ctx);
UNUSED(raw_expr);
rt_expr.eval_func_ = ObExprWeightString::eval_weight_string;
return OB_SUCCESS;
}
uint64_t ObExprWeightString::ob_strxfrm_flag_normalize(uint64_t flags, uint64_t maximum)
{
/* If levels are omitted, then 1-maximum is assumed*/
if (!(flags & OB_STRXFRM_LEVEL_ALL)) {
static uint64_t def_level_flags[]= {0, 0x01, 0x03, 0x07, 0x0F, 0x1F, 0x3F };
uint64_t flag_pad= flags & (OB_STRXFRM_PAD_WITH_SPACE | OB_STRXFRM_PAD_TO_MAXLEN);
flags= def_level_flags[maximum] | flag_pad;
}
else {
uint64_t i = 0;
uint64_t flag_lev= flags & OB_STRXFRM_LEVEL_ALL;
uint64_t flag_dsc= (flags >> OB_STRXFRM_DESC_SHIFT) & OB_STRXFRM_LEVEL_ALL;
uint64_t flag_rev= (flags >> OB_STRXFRM_REVERSE_SHIFT) & OB_STRXFRM_LEVEL_ALL;
uint64_t flag_pad= flags & (OB_STRXFRM_PAD_WITH_SPACE | OB_STRXFRM_PAD_TO_MAXLEN);
/*
If any level number is greater than the maximum,
it is treated as the maximum.
*/
maximum--;
flags= 0;
for (i= 0; i < OB_STRXFRM_NLEVELS; i++)
{
uint64_t src_bit= 1 << i;
if (flag_lev & src_bit) {
uint64_t dst_bit= 1 << OB_MIN(i, maximum);
flags|= dst_bit;
flags|= (flag_dsc & dst_bit) << OB_STRXFRM_DESC_SHIFT;
flags|= (flag_rev & dst_bit) << OB_STRXFRM_REVERSE_SHIFT;
}
}
flags|= flag_pad;
}
return flags;
}
}
}