diff options
| -rw-r--r-- | compression/rle/read_write.go | 60 |
1 files changed, 30 insertions, 30 deletions
diff --git a/compression/rle/read_write.go b/compression/rle/read_write.go index b4b73dab4..a5b80222c 100644 --- a/compression/rle/read_write.go +++ b/compression/rle/read_write.go @@ -45,39 +45,39 @@ func Decompress(dat []byte) ([]byte, error) { return buf.Bytes(), nil } +func compressBlock(dat []byte) (ret []byte, n int) { + switch { + case dat[0] == token: + return []byte{token, tokenToken}, 1 + case len(dat) > 1 && dat[0] == 0x0 && dat[1] == 0x0: + j := 0 + for j <= 254 && j < len(dat) { + if dat[j] != 0 { + break + } + j++ + } + return []byte{token, byte(j + 2)}, j + case len(dat) >= 32: + if dat[0] == empty[0] && bytes.Compare(dat[:32], empty) == 0 { + return []byte{token, emptyShaToken}, 32 + } else if dat[0] == emptyList[0] && bytes.Compare(dat[:32], emptyList) == 0 { + return []byte{token, emptyListShaToken}, 32 + } + fallthrough + default: + return dat[:1], 1 + } +} + func Compress(dat []byte) []byte { buf := new(bytes.Buffer) - for i := 0; i < len(dat); i++ { - if dat[i] == token { - buf.Write([]byte{token, tokenToken}) - } else if i+1 < len(dat) { - if dat[i] == 0x0 && dat[i+1] == 0x0 { - j := 0 - for j <= 254 && i+j < len(dat) { - if dat[i+j] != 0 { - break - } - j++ - } - buf.Write([]byte{token, byte(j + 2)}) - i += (j - 1) - } else if len(dat[i:]) >= 32 { - if dat[i] == empty[0] && bytes.Compare(dat[i:i+32], empty) == 0 { - buf.Write([]byte{token, emptyShaToken}) - i += 31 - } else if dat[i] == emptyList[0] && bytes.Compare(dat[i:i+32], emptyList) == 0 { - buf.Write([]byte{token, emptyListShaToken}) - i += 31 - } else { - buf.WriteByte(dat[i]) - } - } else { - buf.WriteByte(dat[i]) - } - } else { - buf.WriteByte(dat[i]) - } + i := 0 + for i < len(dat) { + b, n := compressBlock(dat[i:]) + buf.Write(b) + i += n } return buf.Bytes() |