83 lines
1.6 KiB
Go
83 lines
1.6 KiB
Go
|
package buffer
|
||
|
|
|
||
|
|
import (
|
||
|
|
"bytes"
|
||
|
|
"encoding/gob"
|
||
|
|
"fmt"
|
||
|
|
"io"
|
||
|
|
|
||
|
|
"github.com/djherbis/buffer/limio"
|
||
|
|
)
|
||
|
|
|
||
|
|
type memory struct {
|
||
|
|
N int64
|
||
|
|
*bytes.Buffer
|
||
|
|
}
|
||
|
|
|
||
|
|
// New returns a new in memory BufferAt with max size N.
|
||
|
|
// It's backed by a bytes.Buffer.
|
||
|
|
func New(n int64) BufferAt {
|
||
|
|
return &memory{
|
||
|
|
N: n,
|
||
|
|
Buffer: bytes.NewBuffer(nil),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (buf *memory) Cap() int64 {
|
||
|
|
return buf.N
|
||
|
|
}
|
||
|
|
|
||
|
|
func (buf *memory) Len() int64 {
|
||
|
|
return int64(buf.Buffer.Len())
|
||
|
|
}
|
||
|
|
|
||
|
|
func (buf *memory) Write(p []byte) (n int, err error) {
|
||
|
|
return limio.LimitWriter(buf.Buffer, Gap(buf)).Write(p)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (buf *memory) WriteAt(p []byte, off int64) (n int, err error) {
|
||
|
|
if off > buf.Len() {
|
||
|
|
return 0, io.ErrShortWrite
|
||
|
|
} else if len64(p)+off <= buf.Len() {
|
||
|
|
d := buf.Bytes()[off:]
|
||
|
|
return copy(d, p), nil
|
||
|
|
} else {
|
||
|
|
d := buf.Bytes()[off:]
|
||
|
|
n = copy(d, p)
|
||
|
|
m, err := buf.Write(p[n:])
|
||
|
|
return n + m, err
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (buf *memory) ReadAt(p []byte, off int64) (n int, err error) {
|
||
|
|
return bytes.NewReader(buf.Bytes()).ReadAt(p, off)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (buf *memory) Read(p []byte) (n int, err error) {
|
||
|
|
return io.LimitReader(buf.Buffer, buf.Len()).Read(p)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (buf *memory) ReadFrom(r io.Reader) (n int64, err error) {
|
||
|
|
return buf.Buffer.ReadFrom(io.LimitReader(r, Gap(buf)))
|
||
|
|
}
|
||
|
|
|
||
|
|
func init() {
|
||
|
|
gob.Register(&memory{})
|
||
|
|
}
|
||
|
|
|
||
|
|
func (buf *memory) MarshalBinary() ([]byte, error) {
|
||
|
|
var b bytes.Buffer
|
||
|
|
fmt.Fprintln(&b, buf.N)
|
||
|
|
b.Write(buf.Bytes())
|
||
|
|
return b.Bytes(), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (buf *memory) UnmarshalBinary(bindata []byte) error {
|
||
|
|
data := make([]byte, len(bindata))
|
||
|
|
copy(data, bindata)
|
||
|
|
b := bytes.NewBuffer(data)
|
||
|
|
_, err := fmt.Fscanln(b, &buf.N)
|
||
|
|
buf.Buffer = bytes.NewBuffer(b.Bytes())
|
||
|
|
return err
|
||
|
|
}
|