/
utils.go
51 lines (42 loc) · 1.16 KB
/
utils.go
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package dbengine
import (
"encoding/binary"
"io"
)
// WriteDataWithVarintSizePrefix - writes data to w with a varint size prefix
func WriteDataWithVarintSizePrefix(w io.Writer, raw []byte) (written int, err error) {
buf := make([]byte, binary.MaxVarintLen64, binary.MaxVarintLen64)
n := binary.PutUvarint(buf, uint64(len(raw)))
buf = buf[:n]
written, err = w.Write(buf)
if err != nil {
return written, err
}
dataWritten, err := w.Write(raw)
written += dataWritten
if err != nil {
return written, err
}
return written, nil
}
// VarintSizePrefixDataReader - a reader interface for varint prefixed data
type VarintSizePrefixDataReader interface {
io.Reader
io.ByteReader
}
// ReadDataWithVarintPrefix - read a varint prefixed data block into buf. If buf is too small
// a new allocated slice will be returned. It is also valid to pass `nil` for buf.
func ReadDataWithVarintPrefix(r VarintSizePrefixDataReader, buf []byte) ([]byte, error) {
l, err := binary.ReadUvarint(r)
if err != nil {
return nil, err
}
if buf == nil || uint64(len(buf)) < l {
buf = make([]byte, l, l)
}
n, err := r.Read(buf)
if err != nil {
return nil, err
}
return buf[:n], nil
}