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package rdb
import (
"errors"
"io"
)
type sliceBuffer struct {
s []byte
i int
}
func newSliceBuffer(s []byte) *sliceBuffer {
return &sliceBuffer{s, 0}
}
func (s *sliceBuffer) Slice(n int) ([]byte, error) {
if s.i+n > len(s.s) {
return nil, io.EOF
}
b := s.s[s.i : s.i+n]
s.i += n
return b, nil
}
func (s *sliceBuffer) ReadByte() (byte, error) {
if s.i >= len(s.s) {
return 0, io.EOF
}
b := s.s[s.i]
s.i++
return b, nil
}
func (s *sliceBuffer) Read(b []byte) (int, error) {
if len(b) == 0 {
return 0, nil
}
if s.i >= len(s.s) {
return 0, io.EOF
}
n := copy(b, s.s[s.i:])
s.i += n
return n, nil
}
func (s *sliceBuffer) Seek(offset int64, whence int) (int64, error) {
var abs int64
switch whence {
case 0:
abs = offset
case 1:
abs = int64(s.i) + offset
case 2:
abs = int64(len(s.s)) + offset
default:
return 0, errors.New("invalid whence")
}
if abs < 0 {
return 0, errors.New("negative position")
}
if abs >= 1<<31 {
return 0, errors.New("position out of range")
}
s.i = int(abs)
return abs, nil
}
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