/
changestream.go
63 lines (47 loc) · 1.03 KB
/
changestream.go
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package server
import (
"bytes"
"io"
)
func NewChangeStream(r io.ReadCloser) io.ReadCloser {
return &ChangeStream{r, []byte{}}
}
type ChangeStream struct {
io.ReadCloser
// being used for temporarily rest, when being replaced with longer
overflow []byte
}
func (cs *ChangeStream) Read(p []byte) (n int, err error) {
copy(p, cs.overflow)
n, err = cs.ReadCloser.Read(p[len(cs.overflow):])
if err == io.EOF {
} else if err != nil {
return n, err
}
cs.overflow = []byte{}
needle := []byte("Politie")
repl := []byte("eitiloP")
// currently we are assuming:
for i := 0; i < n-len(needle); i++ {
if bytes.Compare(p[i:i+len(needle)], needle) != 0 {
continue
}
newIndex := i
// take care of longer, sizes, put in rest buffer.
for j := 0; j < len(repl); j++ {
p[newIndex] = repl[j]
newIndex++
}
oldIndex := i + len(needle)
for oldIndex < n {
p[newIndex] = p[oldIndex]
oldIndex++
newIndex++
}
n = newIndex
}
return n, err
}
func (cs *ChangeStream) Close() error {
return cs.ReadCloser.Close()
}