GZIP Archive

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GZIP, GZ

  • Format Type : Archive
  • Endian Order : Little Endian
  • Signature : 1F 8B


Format Specifications

//header
2 bytes (uint16) - signature // 1F 8B  (35615)
1 byte (uint8) - compression method  //  1-7  - reserved
                                     //  8    - deflate
1 byte (uint8) - flags  // bit 0   FTEXT - file is ASCII text
                        // bit 1   FHCRC - CRC16 for the gzip header is present
                        // bit 2   FEXTRA - optional extra fields are present
                        // bit 3   FNAME - an original file name is present
                        // bit 4   FCOMMENT - a zero-terminated file comment is present
                        // bit 5   reserved
                        // bit 6   reserved
                        // bit 7   reserved
4 bytes (time) - modification time in Unix format
1 byte (uint8) - extra flags  // 2 - compressor used maximum compression, slowest algorithm
                              // 4 - compressor used fastest algorithm
1 byte (uint8) - operating system / file system  // 0 - FAT filesystem (MS-DOS, OS/2, NT/Win32)
                                                 // 1 - Amiga
                                                 // 2 - VMS (or OpenVMS)
                                                 // 3 - Unix
                                                 // 4 - VM/CMS
                                                 // 5 - Atari TOS
                                                 // 6 - HPFS filesystem (OS/2, NT)
                                                 // 7 - Macintosh
                                                 // 8 - Z-System
                                                 // 9 - CP/M
                                                 // 10 - TOPS-20
                                                 // 11 - NTFS filesystem (NT)
                                                 // 12 - QDOS
                                                 // 13 - Acorn RISCOS
                                                 // 255 - unknown


// extra header
x bytes - optional extra header

// body
x bytes - body with DEFLATE compressed payload

// footer
4 bytes - CRC32
4 bytes (uint32) - size of the original (uncompressed) input data modulo 2^32.

Notes and Comments

None.

Games

List of games using this file format:

  • Deja Vu (*.DAT)

QuickBMS Script

Not written yet.

Compatible Programs

  • Winrar (autodetecs files with GZ extension)

See Also