go_sshkeys/internal/utils.go
2022-03-05 19:22:40 -05:00

67 lines
1.2 KiB
Go

package internal
import (
"bytes"
"encoding/binary"
)
/*
ReadSizeBytes returns a uint32 allocator for a given set of data for preparation of packing into bytes.
data can be one of:
- string
- byte/uint8
- []byte/[]uint8
- *bytes.Buffer
- *bytes.Reader
If pack is true, the original data will be appended to the returned allocated *bytes.Reader.
NOTE: If data is a *bytes.Reader, the bytes WILL be consumed within that reader.
*/
func ReadSizeBytes(data interface{}, pack bool) (allocated *bytes.Reader, err error) {
var u uint32
var b []byte
var sizer []byte = make([]byte, 4)
switch t := data.(type) {
case string:
b = []byte(t)
case byte:
// b = []byte{0x0, 0x0, 0x0, 0x1}
b = []byte{t}
case []byte:
b = t
case bytes.Buffer:
t2 := &t
b = t2.Bytes()
case *bytes.Buffer:
b = t.Bytes()
case bytes.Reader:
t2 := &t
b = make([]byte, t2.Len())
if _, err = t2.Read(b); err != nil {
return
}
case *bytes.Reader:
b = make([]byte, t.Len())
if _, err = t.Read(b); err != nil {
return
}
}
u = uint32(len(b))
binary.BigEndian.PutUint32(sizer, u)
if !pack {
allocated = bytes.NewReader(sizer)
} else {
b = append(sizer, b...)
allocated = bytes.NewReader(b)
}
return
}