79 lines
1.4 KiB
Go
79 lines
1.4 KiB
Go
//Package b64 encodes base64 and does formating for S/MIME
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package b64
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import (
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"bytes"
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"encoding/base64"
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"io"
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)
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// From https://golang.org/src/encoding/pem/pem.go
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//Takes an byteslice and outputs the base64 encoded version with linebreaks. The constant PemLineLength defines the lenght of the lines.
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func EncodeBase64(in []byte) ([]byte, error) {
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var buf bytes.Buffer
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var breaker lineBreaker
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breaker.out = &buf
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b64 := base64.NewEncoder(base64.StdEncoding, &breaker)
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if _, err := b64.Write(in); err != nil {
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return nil, err
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}
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b64.Close()
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breaker.Close()
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return buf.Bytes(), nil
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}
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//Lenght of the lines in the output of the function EncodeBase64.
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const PemLineLength = 64
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type lineBreaker struct {
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line [PemLineLength]byte
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used int
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out io.Writer
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}
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var nl = []byte{'\n'}
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func (l *lineBreaker) Write(b []byte) (n int, err error) {
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if l.used+len(b) < PemLineLength {
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copy(l.line[l.used:], b)
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l.used += len(b)
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return len(b), nil
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}
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n, err = l.out.Write(l.line[0:l.used])
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if err != nil {
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return
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}
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excess := PemLineLength - l.used
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l.used = 0
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n, err = l.out.Write(b[0:excess])
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if err != nil {
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return
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}
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n, err = l.out.Write(nl)
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if err != nil {
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return
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}
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return l.Write(b[excess:])
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}
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func (l *lineBreaker) Close() (err error) {
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if l.used > 0 {
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_, err = l.out.Write(l.line[0:l.used])
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if err != nil {
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return
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}
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_, err = l.out.Write(nl)
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}
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return
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}
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