extra.fld
来自「zip压缩」· FLD 代码 · 共 1,244 行 · 第 1/4 页
FLD
1,244 行
================================== The following is the layout of the new Info-ZIP extra block for Unix. (Last Revision 19960922) Local-header version: Value Size Description ----- ---- ----------- (Unix2) 0x7855 Short tag for this extra block type ("Ux") TSize Short total data size for this block (4) UID Short Unix user ID GID Short Unix group ID Central-header version: Value Size Description ----- ---- ----------- (Unix2) 0x7855 Short tag for this extra block type ("Ux") TSize Short total data size for this block (0) The data size of the central-header version is zero; it is used solely as a flag that UID/GID info is present in the local-header extra field. If additional fields are ever added to the local version, the central version may be extended to indicate this. Note that Unix UIDs and GIDs are usually specific to a particular machine, and they generally require root access to restore. -ASi Unix Extra Field: ==================== The following is the layout of the ASi extra block for Unix. The local-header and central-header versions are identical. (Last Revision 19960916) Value Size Description ----- ---- ----------- (Unix3) 0x756e Short tag for this extra block type ("nu") TSize Short total data size for this block CRC Long CRC-32 of the remaining data Mode Short file permissions SizDev Long symlink'd size OR major/minor dev num UID Short user ID GID Short group ID (var.) variable symbolic link filename Mode is the standard Unix st_mode field from struct stat, containing user/group/other permissions, setuid/setgid and symlink info, etc. If Mode indicates that this file is a symbolic link, SizDev is the size of the file to which the link points. Otherwise, if the file is a device, SizDev contains the standard Unix st_rdev field from struct stat (includes the major and minor numbers of the device). SizDev is undefined in other cases. If Mode indicates that the file is a symbolic link, the final field will be the name of the file to which the link points. The file- name length can be inferred from TSize. [Note that TSize may incorrectly refer to the data size not counting the CRC; i.e., it may be four bytes too small.] -BeOS Extra Field: ================ The following is the layout of the file-attributes extra block for BeOS. (Last Revision 19970531) Local-header version: Value Size Description ----- ---- ----------- (BeOS) 0x6542 Short tag for this extra block type ("Be") TSize Short total data size for this block BSize Long uncompressed file attribute data size Flags Byte info bits (CType) Short compression type (CRC) Long CRC value for uncompressed file attribs Attribs variable file attribute data Central-header version: Value Size Description ----- ---- ----------- (BeOS) 0x6542 Short tag for this extra block type ("Be") TSize Short total data size for this block (5) BSize Long size of uncompr. local EF block data Flags Byte info bits The least significant bit of Flags in both headers indicates whether the LOCAL extra field is uncompressed (and therefore whether CType and CRC are omitted): bit 0 if set, Attribs is uncompressed (no CType, CRC) bits 1-7 reserved; if set, assume error or unknown data Currently the only supported compression types are deflated (type 8) and stored (type 0); the latter is not used by Info-ZIP's Zip but is supported by UnZip. Attribs is a BeOS-specific block of data in big-endian format with the following structure (if compressed, uncompress it first): Value Size Description ----- ---- ----------- Name variable attribute name (null-terminated string) Type Long attribute type (32-bit unsigned integer) Size Long Long data size for this sub-block (64 bits) Data variable attribute data The attribute structure is repeated for every attribute. The Data field may contain anything--text, flags, bitmaps, etc. -SMS/QDOS Extra Field: ==================== The following is the layout of the file-attributes extra block for SMS/QDOS. The local-header and central-header versions are identical. (Last Revision 19960929) Value Size Description ----- ---- ----------- (QDOS) 0xfb4a Short tag for this extra block type TSize Short total data size for this block LongID Long extra-field signature (ExtraID) Long additional signature/flag bytes QDirect 64 bytes qdirect structure LongID may be "QZHD" or "QDOS". In the latter case, ExtraID will be present. Its first three bytes are "02\0"; the last byte is currently undefined. QDirect contains the file's uncompressed directory info (qdirect struct). Its elements are in native (big-endian) format: d_length beLong file length d_access byte file access type d_type byte file type d_datalen beLong data length d_reserved beLong unused d_szname beShort size of filename d_name 36 bytes filename d_update beLong time of last update d_refdate beLong file version number d_backup beLong time of last backup (archive date) -AOS/VS Extra Field: ================== The following is the layout of the extra block for Data General AOS/VS. The local-header and central-header versions are identical. (Last Revision 19961125) Value Size Description ----- ---- ----------- (AOSVS) 0x5356 Short tag for this extra block type ("VS") TSize Short total data size for this block "FCI\0" Long extra-field signature Version Byte version of AOS/VS extra block (10 = 1.0) Fstat variable fstat packet AclBuf variable raw ACL data ($MXACL bytes) Fstat contains the file's uncompressed fstat packet, which is one of the following: normal fstat packet (P_FSTAT struct) DIR/CPD fstat packet (P_FSTAT_DIR struct) unit (device) fstat packet (P_FSTAT_UNIT struct) IPC file fstat packet (P_FSTAT_IPC struct) AclBuf contains the raw ACL data; its length is $MXACL. -Tandem NSK Extra Field: ====================== The following is the layout of the file-attributes extra block for Tandem NSK. The local-header and central-header versions are identical. (Last Revision 19981221) Value Size Description ----- ---- ----------- (TA) 0x4154 Short tag for this extra block type ("TA") TSize Short total data size for this block (20) NSKattrs 20 Bytes NSK attributes -THEOS Extra Field: ================= The following is the layout of the file-attributes extra block for Theos. The local-header and central-header versions are identical. (Last Revision 19990206) Value Size Description ----- ---- ----------- (Theos) 0x6854 Short 'Th' signature size Short size of extra block flags Byte reserved for future use filesize Long file size fileorg Byte type of file (see below) keylen Short key length for indexed and keyed files, data segment size for 16 bits programs reclen Short record length for indexed,keyed and direct, text segment size for 16 bits programs filegrow Byte growing factor for indexed,keyed and direct protect Byte protections (see below) reserved Short reserved for future use File types ========== 0x80 library (keyed access list of files) 0x40 directory 0x10 stream file 0x08 direct file 0x04 keyed file 0x02 indexed file 0x0e reserved 0x01 16 bits real mode program (obsolete) 0x21 16 bits protected mode program 0x41 32 bits protected mode program Protection codes ================ User protection --------------- 0x01 non readable 0x02 non writable 0x04 non executable 0x08 non erasable Other protection ---------------- 0x10 non readable 0x20 non writable 0x40 non executable Theos before 4.0 0x40 modified Theos 4.x 0x80 not hidden -THEOS old inofficial Extra Field: ================================ The following is the layout of an inoffical former version of a Theos file-attributes extra blocks. This layout was never published and is no longer created. However, UnZip can optionally support it when compiling with the option flag OLD_THEOS_EXTRA defined. Both the local-header and central-header versions are identical. (Last Revision 19990206) Value Size Description ----- ---- ----------- (THS0) 0x4854 Short 'TH' signature size Short size of extra block flags Short reserved for future use filesize Long file size reclen Short record length for indexed,keyed and direct, text segment size for 16 bits programs keylen Short key length for indexed and keyed files, data segment size for 16 bits programs filegrow Byte growing factor for indexed,keyed and direct reserved 3 Bytes reserved for future use -FWKCS MD5 Extra Field: ===================== The FWKCS Contents_Signature System, used in automatically identifying files independent of filename, optionally adds and uses an extra field to support the rapid creation of an enhanced contents_signature. There is no local-header version; the following applies only to the central header. (Last Revision 19961207) Central-header version: Value Size Description ----- ---- ----------- (MD5) 0x4b46 Short tag for this extra block type ("FK") TSize Short total data size for this block (19) "MD5" 3 bytes extra-field signature MD5hash 16 bytes 128-bit MD5 hash of uncompressed data (low byte first) When FWKCS revises a .ZIP file central directory to add this extra field for a file, it also replaces the central directory entry for that file's uncompressed file length with a measured value. FWKCS provides an option to strip this extra field, if present, from a .ZIP file central directory. In adding this extra field, FWKCS preserves .ZIP file Authenticity Verification; if stripping this extra field, FWKCS preserves all versions of AV through PKZIP version 2.04g. FWKCS, and FWKCS Contents_Signature System, are trademarks of Frederick W. Kantor. (1) R. Rivest, RFC1321.TXT, MIT Laboratory for Computer Science and RSA Data Security, Inc., April 1992. ll.76-77: "The MD5 algorithm is being placed in the public domain for review and possible adoption as a standard."⌨️ 快捷键说明
复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?