Copy copies bits from src to dst, seeking past blocks of zero bits in src. These blocks are omitted, creating a file with holes in dst.
(dst io.WriteSeeker, src io.Reader, buf []byte)
| 21 | // Copy copies bits from src to dst, seeking past blocks of zero bits in src. These |
| 22 | // blocks are omitted, creating a file with holes in dst. |
| 23 | func copyBuffer(dst io.WriteSeeker, src io.Reader, buf []byte) (written int64, err error) { |
| 24 | for { |
| 25 | nr, er := src.Read(buf) |
| 26 | if nr > 0 { //nolint:nestif |
| 27 | // If non-zero data is read, write it. Otherwise, skip forwards. |
| 28 | if isAllZero(buf) { |
| 29 | dst.Seek(int64(nr), io.SeekCurrent) //nolint:errcheck |
| 30 | written += int64(nr) |
| 31 | |
| 32 | continue |
| 33 | } |
| 34 | |
| 35 | nw, ew := dst.Write(buf[0:nr]) |
| 36 | if nw < 0 || nr < nw { |
| 37 | nw = 0 |
| 38 | |
| 39 | if ew == nil { |
| 40 | ew = errors.New("invalid write result") |
| 41 | } |
| 42 | } |
| 43 | |
| 44 | written += int64(nw) |
| 45 | |
| 46 | if ew != nil { |
| 47 | err = ew |
| 48 | break |
| 49 | } |
| 50 | |
| 51 | if nr != nw { |
| 52 | err = io.ErrShortWrite |
| 53 | break |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | if er != nil { |
| 58 | if er != io.EOF { |
| 59 | err = er |
| 60 | } |
| 61 | |
| 62 | break |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | return written, err |
| 67 | } |
| 68 | |
| 69 | func isAllZero(buf []byte) bool { |
| 70 | for _, b := range buf { |