package restorer import ( "github.com/restic/restic/internal/restic" ) // WriteAt writes p to f.File at offset. It tries to do a sparse write // and updates f.size. func (f *partialFile) WriteAt(p []byte, offset int64) (n int, err error) { if !f.sparse { return f.File.WriteAt(p, offset) } n = len(p) // Skip the longest all-zero prefix of p. // If it's long enough, we can punch a hole in the file. skipped := restic.ZeroPrefixLen(p) p = p[skipped:] offset += int64(skipped) switch { case len(p) == 0: // All zeros, file already big enough. A previous WriteAt or // Truncate will have produced the zeros in f.File. default: var n2 int n2, err = f.File.WriteAt(p, offset) n = skipped + n2 } return n, err }