github.com/datastax/go-cassandra-native-protocol@v0.0.0-20220706104457-5e8aad05cf90/primitive/string_list.go (about)

     1  // Copyright 2020 DataStax
     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 primitive
    16  
    17  import (
    18  	"fmt"
    19  	"io"
    20  )
    21  
    22  // [string list]
    23  
    24  func ReadStringList(source io.Reader) (decoded []string, err error) {
    25  	var length uint16
    26  	length, err = ReadShort(source)
    27  	if err != nil {
    28  		return nil, fmt.Errorf("cannot read [string list] length: %w", err)
    29  	}
    30  
    31  	if length < 0 {
    32  		return nil, nil
    33  	} else if length == 0 {
    34  		return []string{}, nil
    35  	}
    36  
    37  	decoded = make([]string, length)
    38  	for i := uint16(0); i < length; i++ {
    39  		var str string
    40  		str, err = ReadString(source)
    41  		if err != nil {
    42  			return nil, fmt.Errorf("cannot read [string list] element %d: %w", i, err)
    43  		}
    44  		decoded[i] = str
    45  	}
    46  	return decoded, nil
    47  }
    48  
    49  func WriteStringList(list []string, dest io.Writer) error {
    50  	length := len(list)
    51  	if err := WriteShort(uint16(length), dest); err != nil {
    52  		return fmt.Errorf("cannot write [string list] length: %w", err)
    53  	}
    54  	for i, s := range list {
    55  		if err := WriteString(s, dest); err != nil {
    56  			return fmt.Errorf("cannot write [string list] element %d: %w", i, err)
    57  		}
    58  	}
    59  	return nil
    60  }
    61  
    62  func LengthOfStringList(list []string) int {
    63  	length := LengthOfShort
    64  	for _, s := range list {
    65  		length += LengthOfString(s)
    66  	}
    67  	return length
    68  }