github.com/datastax/go-cassandra-native-protocol@v0.0.0-20220706104457-5e8aad05cf90/primitive/long_string.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  	"errors"
    19  	"fmt"
    20  	"io"
    21  )
    22  
    23  // [long string]
    24  
    25  func ReadLongString(source io.Reader) (string, error) {
    26  	if length, err := ReadInt(source); err != nil {
    27  		return "", fmt.Errorf("cannot read [long string] length: %w", err)
    28  	} else if length <= 0 {
    29  		return "", nil
    30  	} else {
    31  		decoded := make([]byte, length)
    32  		if _, err := io.ReadFull(source, decoded); err != nil {
    33  			return "", fmt.Errorf("cannot read [long string] content: %w", err)
    34  		}
    35  		return string(decoded), nil
    36  	}
    37  }
    38  
    39  func WriteLongString(s string, dest io.Writer) error {
    40  	length := len(s)
    41  	if err := WriteInt(int32(length), dest); err != nil {
    42  		return fmt.Errorf("cannot write [long string] length: %w", err)
    43  	} else if n, err := dest.Write([]byte(s)); err != nil {
    44  		return fmt.Errorf("cannot write [long string] length: %w", err)
    45  	} else if n < length {
    46  		return errors.New("not enough capacity to write [long string] content")
    47  	}
    48  	return nil
    49  }
    50  
    51  func LengthOfLongString(s string) int {
    52  	return LengthOfInt + len(s)
    53  }