package toreader import "io" type OffsetReader struct { r io.ReaderAt off int64 } func NewOffsetReader(r io.ReaderAt, off int64) *OffsetReader { return &OffsetReader{ r: r, off: off, } } func (r OffsetReader) ReadAt(p []byte, off int64) (n int, e error) { return r.r.ReadAt(p, off+r.off) }