71 lines
1.4 KiB
Go
71 lines
1.4 KiB
Go
// SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
|
|
//
|
|
// SPDX-License-Identifier: MIT
|
|
|
|
package mail
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
)
|
|
|
|
// ErrNoOutWriter is an error message that should be used if a Base64LineBreaker has no out io.Writer set
|
|
const ErrNoOutWriter = "no io.Writer set for Base64LineBreaker"
|
|
|
|
// Base64LineBreaker is an io.WriteCloser that writes Base64 encoded data streams
|
|
// with line breaks at a given line length
|
|
type Base64LineBreaker struct {
|
|
line [MaxBodyLength]byte
|
|
used int
|
|
out io.Writer
|
|
}
|
|
|
|
var nl = []byte(SingleNewLine)
|
|
|
|
// Write writes the data stream and inserts a SingleNewLine when the maximum
|
|
// line length is reached
|
|
func (l *Base64LineBreaker) Write(b []byte) (n int, err error) {
|
|
if l.out == nil {
|
|
err = fmt.Errorf(ErrNoOutWriter)
|
|
return
|
|
}
|
|
if l.used+len(b) < MaxBodyLength {
|
|
copy(l.line[l.used:], b)
|
|
l.used += len(b)
|
|
return len(b), nil
|
|
}
|
|
|
|
n, err = l.out.Write(l.line[0:l.used])
|
|
if err != nil {
|
|
return
|
|
}
|
|
excess := MaxBodyLength - l.used
|
|
l.used = 0
|
|
|
|
n, err = l.out.Write(b[0:excess])
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
n, err = l.out.Write(nl)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
return l.Write(b[excess:])
|
|
}
|
|
|
|
// Close closes the Base64LineBreaker and writes any access data that is still
|
|
// unwritten in memory
|
|
func (l *Base64LineBreaker) Close() (err error) {
|
|
if l.used > 0 {
|
|
_, err = l.out.Write(l.line[0:l.used])
|
|
if err != nil {
|
|
return
|
|
}
|
|
_, err = l.out.Write(nl)
|
|
}
|
|
|
|
return
|
|
}
|