github.com/matrixorigin/matrixone@v0.7.0/pkg/sql/plan/function/builtin/multi/trim.go (about)

     1  // Copyright 2022 Matrix Origin
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package multi
    16  
    17  import (
    18  	"github.com/matrixorigin/matrixone/pkg/common/moerr"
    19  	"github.com/matrixorigin/matrixone/pkg/container/types"
    20  	"github.com/matrixorigin/matrixone/pkg/container/vector"
    21  	"github.com/matrixorigin/matrixone/pkg/vm/process"
    22  	"strings"
    23  )
    24  
    25  func trimBoth(src, cuts string) string {
    26  	if len(cuts) == 0 {
    27  		return src
    28  	}
    29  	return trimLeading(trimTrailing(src, cuts), cuts)
    30  }
    31  
    32  func trimLeading(src, cuts string) string {
    33  	if len(cuts) == 0 {
    34  		return src
    35  	}
    36  	for strings.HasPrefix(src, cuts) {
    37  		src = src[len(cuts):]
    38  	}
    39  	return src
    40  }
    41  
    42  func trimTrailing(src, cuts string) string {
    43  	if len(cuts) == 0 {
    44  		return src
    45  	}
    46  	for strings.HasSuffix(src, cuts) {
    47  		src = src[:len(src)-len(cuts)]
    48  	}
    49  	return src
    50  }
    51  
    52  func Trim(parameters []*vector.Vector, result vector.FunctionResultWrapper, proc *process.Process, length int) error {
    53  	tp := strings.ToLower(vector.MustStrCols(parameters[0])[0])
    54  	switch tp {
    55  	case "both":
    56  		return trim(parameters[1:], result, length, trimBoth)
    57  	case "leading":
    58  		return trim(parameters[1:], result, length, trimLeading)
    59  	case "trailing":
    60  		return trim(parameters[1:], result, length, trimTrailing)
    61  	default:
    62  		return moerr.NewNotSupported(proc.Ctx, "trim type %s", tp)
    63  	}
    64  }
    65  
    66  func trim(parameters []*vector.Vector, result vector.FunctionResultWrapper, length int, trimFn func(string, string) string) error {
    67  	cutsets := vector.GenerateFunctionStrParameter(parameters[0])
    68  	origin := vector.GenerateFunctionStrParameter(parameters[1])
    69  	rs := vector.MustFunctionResult[types.Varlena](result)
    70  	for i := uint64(0); i < uint64(length); i++ {
    71  		cutset, cIsNull := cutsets.GetStrValue(i)
    72  		orig, oIsNull := origin.GetStrValue(i)
    73  		if cIsNull || oIsNull {
    74  			if err := rs.AppendStr(nil, true); err != nil {
    75  				return err
    76  			}
    77  			continue
    78  		}
    79  		if err := rs.AppendStr([]byte(trimFn(string(orig), string(cutset))), false); err != nil {
    80  			return err
    81  		}
    82  	}
    83  	return nil
    84  }