public LocalFile GetLocalFile(int i)
{
LocalFile lf = new()
{
Filename = Path.GetFileName(ZipFilename),
UncompressedSize = UnCompressedSize,
CRC = this.CRC,
IsDirectory = false,
ModifiedTime = MTime == 0 ? null : (long?)CompressUtils.UtcTicksFromUnixDateTime((int)MTime)
};
return(lf);
}
public static ZipReturn ReadExtraField(byte[] extraField, byte[] bFileName,
LocalFile lf, ref ulong compressedSize, ref ulong relativeOffsetOfLocalHeader,
bool centralDir)
{
int extraFieldLength = extraField.Length;
lf.SetStatus(LocalFileStatus.Zip64, false);
lf.ModifiedTime = null;
lf.AccessedTime = null;
lf.CreatedTime = null;
int blockPos = 0;
// the +4 is added as there must be at least 4 bytes more to read to get the next blocks type and blockLength
// this is added to handle some incorrectly format extra data fields.
while (blockPos <= extraFieldLength - 4)
{
ushort type = BitConverter.ToUInt16(extraField, blockPos);
blockPos += 2;
ushort blockLength = BitConverter.ToUInt16(extraField, blockPos);
blockPos += 2;
int pos = blockPos;
switch (type)
{
/*
* -Zip64 Extended Information Extra Field (0x0001):
* ===============================================
*
* The following is the layout of the zip64 extended
* information "extra" block. If one of the size or
* offset fields in the Local or Central directory
* record is too small to hold the required data,
* a zip64 extended information record is created.
* The order of the fields in the zip64 extended
* information record is fixed, but the fields will
* only appear if the corresponding Local or Central
* directory record field is set to 0xFFFF or 0xFFFFFFFF.
*
* Note: all fields stored in Intel low-byte/high-byte order.
*
* Value Size Description
* ----- ---- -----------
* (ZIP64) 0x0001 2 bytes Tag for this "extra" block type
* Size 2 bytes Size of this "extra" block
* Original
* Size 8 bytes Original uncompressed file size
* Compressed
* Size 8 bytes Size of compressed data
* Relative Header
* Offset 8 bytes Offset of local header record
* Disk Start
* Number 4 bytes Number of the disk on which
* this file starts
*
* This entry in the Local header must include BOTH original
* and compressed file size fields. If encrypting the
* central directory and bit 13 of the general purpose bit
* flag is set indicating masking, the value stored in the
* Local Header for the original file size will be zero.
*/
case 0x0001:
lf.SetStatus(LocalFileStatus.Zip64);
if (lf.UncompressedSize == 0xffffffff)
{
lf.UncompressedSize = BitConverter.ToUInt64(extraField, pos);
pos += 8;
}
if (compressedSize == 0xffffffff)
{
compressedSize = BitConverter.ToUInt64(extraField, pos);
pos += 8;
}
if (centralDir)
{
if (relativeOffsetOfLocalHeader == 0xffffffff)
{
relativeOffsetOfLocalHeader = BitConverter.ToUInt64(extraField, pos);
pos += 8;
}
}
break;
/* PKWARE's authenticity verification */
case 0x0007: // Not Needed
break;
/*
* -PKWARE Win95/WinNT Extra Field (0x000a):
* =======================================
*
* The following description covers PKWARE's "NTFS" attributes
* "extra" block, introduced with the release of PKZIP 2.50 for
* Windows. (Last Revision 20001118)
*
* (Note: At this time the Mtime, Atime and Ctime values may
* be used on any WIN32 system.)
* [Info-ZIP note: In the current implementations, this field has
* a fixed total data size of 32 bytes and is only stored as local
* extra field.]
*
* Value Size Description
* ----- ---- -----------
* (NTFS) 0x000a Short Tag for this "extra" block type
* TSize Short Total Data Size for this block
* Reserved Long for future use
* Tag1 Short NTFS attribute tag value #1
* Size1 Short Size of attribute #1, in bytes
* (var.) SubSize1 Attribute #1 data
* .
* .
* .
* TagN Short NTFS attribute tag value #N
* SizeN Short Size of attribute #N, in bytes
* (var.) SubSizeN Attribute #N data
*
* For NTFS, values for Tag1 through TagN are as follows:
* (currently only one set of attributes is defined for NTFS)
*
* Tag Size Description
* ----- ---- -----------
* 0x0001 2 bytes Tag for attribute #1
* Size1 2 bytes Size of attribute #1, in bytes (24)
* Mtime 8 bytes 64-bit NTFS file last modification time
* Atime 8 bytes 64-bit NTFS file last access time
* Ctime 8 bytes 64-bit NTFS file creation time
*
* The total length for this block is 28 bytes, resulting in a
* fixed size value of 32 for the TSize field of the NTFS block.
*
* The NTFS filetimes are 64-bit unsigned integers, stored in Intel
* (least significant byte first) byte order. They determine the
* number of 1.0E-07 seconds (1/10th microseconds!) past WinNT "epoch",
* which is "01-Jan-1601 00:00:00 UTC".
*
*
* Additional Notes
* ================
* WinRar only write this to the central Directory
*/
case 0x000a:
pos += 4; // Reserved Long for future use
int tag1 = BitConverter.ToInt16(extraField, pos); // Tag1 Short NTFS attribute tag value #1
pos += 2;
int size1 = BitConverter.ToInt16(extraField, pos); // Size1 Short Size of attribute #1, in bytes
pos += 2;
if (tag1 == 0x0001 && size1 == 24
) // (currently only one set of attributes is defined for NTFS)
{
lf.ModifiedTime = CompressUtils.UtcTicksFromNtfsDateTime(BitConverter.ToInt64(extraField, pos)); // Mtime 8 bytes 64-bit NTFS file last modification time
pos += 8;
lf.AccessedTime = CompressUtils.UtcTicksFromNtfsDateTime(BitConverter.ToInt64(extraField, pos)); // Atime 8 bytes 64-bit NTFS file last access time
pos += 8;
lf.CreatedTime = CompressUtils.UtcTicksFromNtfsDateTime(BitConverter.ToInt64(extraField, pos)); // Ctime 8 bytes 64-bit NTFS file creation time
pos += 8;
Debug.WriteLine("modtime = " + new DateTime((long)lf.ModifiedTime));
Debug.WriteLine("Acctime = " + new DateTime((long)lf.AccessedTime));
Debug.WriteLine("Cretime = " + new DateTime((long)lf.CreatedTime));
}
break;
/*
* -Windows NT Security Descriptor Extra Field (0x4453):
* ===================================================
*
* The following is the layout of the NT Security Descriptor (another
* type of ACL) extra block. (Last Revision 19960922)
*
* Local-header version:
*
* Value Size Description
* ----- ---- -----------
* (SD) 0x4453 Short tag for this extra block type ("SD")
* TSize Short total data size for this block
* BSize Long uncompressed SD data size
* Version Byte version of uncompressed SD data format
* CType Short compression type
* EACRC Long CRC value for uncompressed SD data
* (var.) variable compressed SD data
*
* Central-header version:
*
* Value Size Description
* ----- ---- -----------
* (SD) 0x4453 Short tag for this extra block type ("SD")
* TSize Short total data size for this block (4)
* BSize Long size of uncompressed local SD data
*
* The value of CType is interpreted according to the "compression
* method" section above; i.e., 0 for stored, 8 for deflated, etc.
* Version specifies how the compressed data are to be interpreted
* and allows for future expansion of this extra field type. Currently
* only version 0 is defined.
*
* For version 0, the compressed data are to be interpreted as a single
* valid Windows NT SECURITY_DESCRIPTOR data structure, in self-relative
* format.
*
*/
case 0x4453: // Not Needed
break;
/*
* -FWKCS MD5 Extra Field (0x4b46):
* ==============================
*
* 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."
*/
case 0x4B46: // Not Needed
break;
/*
* -Extended Timestamp Extra Field:
* ==============================
*
* The following is the layout of the extended-timestamp extra block.
* (Last Revision 19970118)
*
* Local-header version:
*
* Value Size Description
* ----- ---- -----------
* (time) 0x5455 Short tag for this extra block type ("UT")
* TSize Short total data size for this block
* Flags Byte info bits
* (ModTime) Long time of last modification (UTC/GMT)
* (AcTime) Long time of last access (UTC/GMT)
* (CrTime) Long time of original creation (UTC/GMT)
*
* Central-header version:
*
* Value Size Description
* ----- ---- -----------
* (time) 0x5455 Short tag for this extra block type ("UT")
* TSize Short total data size for this block
* Flags Byte info bits (refers to local header!)
* (ModTime) Long time of last modification (UTC/GMT)
*
* The central-header extra field contains the modification time only,
* or no timestamp at all. TSize is used to flag its presence or
* absence. But note:
*
* If "Flags" indicates that Modtime is present in the local header
* field, it MUST be present in the central header field, too!
* This correspondence is required because the modification time
* value may be used to support trans-timezone freshening and
* updating operations with zip archives.
*
* The time values are in standard Unix signed-long format, indicating
* the number of seconds since 1 January 1970 00:00:00. The times
* are relative to Coordinated Universal Time (UTC), also sometimes
* referred to as Greenwich Mean Time (GMT). To convert to local time,
* the software must know the local timezone offset from UTC/GMT.
*
* The lower three bits of Flags in both headers indicate which time-
* stamps are present in the LOCAL extra field:
*
* bit 0 if set, modification time is present
* bit 1 if set, access time is present
* bit 2 if set, creation time is present
* bits 3-7 reserved for additional timestamps; not set
*
* Those times that are present will appear in the order indicated, but
* any combination of times may be omitted. (Creation time may be
* present without access time, for example.) TSize should equal
* (1 + 4*(number of set bits in Flags)), as the block is currently
* defined. Other timestamps may be added in the future.
*/
case 0x5455:
byte flags = extraField[pos];
pos += 1;
if ((flags & 1) == 1)
{
lf.ModifiedTime = CompressUtils.UtcTicksFromUnixDateTime(BitConverter.ToInt32(extraField, pos)); // (ModTime) Long time of last modification (UTC/GMT)
Debug.WriteLine("Umodtime = " + new DateTime((long)lf.ModifiedTime));
pos += 4;
}
if (!centralDir)
{
if ((flags & 2) == 2)
{
lf.AccessedTime = CompressUtils.UtcTicksFromUnixDateTime(BitConverter.ToInt32(extraField, pos)); // (AcTime) Long time of last access (UTC/GMT)
Debug.WriteLine("UAcctime = " + new DateTime((long)lf.AccessedTime));
pos += 4;
}
if ((flags & 4) == 4)
{
lf.CreatedTime = CompressUtils.UtcTicksFromUnixDateTime(BitConverter.ToInt32(extraField, pos)); // (CrTime) Long time of original creation (UTC/GMT)
Debug.WriteLine("UCretime = " + new DateTime((long)lf.CreatedTime));
pos += 4;
}
}
break;
/*
* -Info-ZIP Unix Extra Field (type 1):
* ==================================
*
* The following is the layout of the old Info-ZIP extra block for
* Unix. It has been replaced by the extended-timestamp extra block
* (0x5455) and the Unix type 2 extra block (0x7855).
* (Last Revision 19970118)
*
* Local-header version:
*
* Value Size Description
* ----- ---- -----------
* (Unix1) 0x5855 Short tag for this extra block type ("UX")
* TSize Short total data size for this block
* AcTime Long time of last access (UTC/GMT)
* ModTime Long time of last modification (UTC/GMT)
* UID Short Unix user ID (optional)
* GID Short Unix group ID (optional)
*
* Central-header version:
*
* Value Size Description
* ----- ---- -----------
* (Unix1) 0x5855 Short tag for this extra block type ("UX")
* TSize Short total data size for this block
* AcTime Long time of last access (GMT/UTC)
* ModTime Long time of last modification (GMT/UTC)
*
* The file access and modification times are in standard Unix signed-
* long format, indicating the number of seconds since 1 January 1970
* 00:00:00. The times are relative to Coordinated Universal Time
* (UTC), also sometimes referred to as Greenwich Mean Time (GMT). To
* convert to local time, the software must know the local timezone
* offset from UTC/GMT. The modification time may be used by non-Unix
* systems to support inter-timezone freshening and updating of zip
* archives.
*
* The local-header extra block may optionally contain UID and GID
* info for the file. The local-header TSize value is the only
* indication of this. Note that Unix UIDs and GIDs are usually
* specific to a particular machine, and they generally require root
* access to restore.
*
* This extra field type is obsolete, but it has been in use since
* mid-1994. Therefore future archiving software should continue to
* support it. Some guidelines:
*
* An archive member should either contain the old "Unix1"
* extra field block or the new extra field types "time" and/or
* "Unix2".
*
* If both the old "Unix1" block type and one or both of the new
* block types "time" and "Unix2" are found, the "Unix1" block
* should be considered invalid and ignored.
*
* Unarchiving software should recognize both old and new extra
* field block types, but the info from new types overrides the
* old "Unix1" field.
*
* Archiving software should recognize "Unix1" extra fields for
* timestamp comparison but never create it for updated, freshened
* or new archive members. When copying existing members to a new
* archive, any "Unix1" extra field blocks should be converted to
* the new "time" and/or "Unix2" types.
*/
case 0x5855:
lf.AccessedTime = CompressUtils.UtcTicksFromUnixDateTime(BitConverter.ToInt32(extraField, pos)); // AcTime Long time of last access (UTC/GMT)
Debug.WriteLine("UAcctime = " + new DateTime((long)lf.AccessedTime));
pos += 4;
lf.ModifiedTime = CompressUtils.UtcTicksFromUnixDateTime(BitConverter.ToInt32(extraField, pos)); // ModTime Long time of last modification (UTC/GMT)
Debug.WriteLine("Umodtime = " + new DateTime((long)lf.ModifiedTime));
pos += 4;
break;
/*
* -Info-ZIP Unicode Path Extra Field:
* =================================
*
* Stores the UTF-8 version of the entry path as stored in the
* local header and central directory header.
* (Last Revision 20070912)
*
* Value Size Description
* ----- ---- -----------
* (UPath) 0x7075 Short tag for this extra block type ("up")
* TSize Short total data size for this block
* Version Byte version of this extra field, currently 1
* NameCRC32 Long CRC-32 checksum of standard name field
* UnicodeName variable UTF-8 version of the entry file name
*
* Currently Version is set to the number 1. If there is a need
* to change this field, the version will be incremented. Changes
* may not be backward compatible so this extra field should not be
* used if the version is not recognized.
*
* The NameCRC32 is the standard zip CRC32 checksum of the File Name
* field in the header. This is used to verify that the header
* File Name field has not changed since the Unicode Path extra field
* was created. This can happen if a utility renames the entry but
* does not update the UTF-8 path extra field. If the CRC check fails,
* this UTF-8 Path Extra Field should be ignored and the File Name field
* in the header should be used instead.
*
* The UnicodeName is the UTF-8 version of the contents of the File
* Name field in the header, without any trailing NUL. The standard
* name field in the Zip entry header remains filled with the entry
* name coded in the local machine's extended ASCII system charset.
* As UnicodeName is defined to be UTF-8, no UTF-8 byte order mark
* (BOM) is used. The length of this field is determined by
* subtracting the size of the previous fields from TSize.
* If both the File Name and Comment fields are UTF-8, the new General
* Purpose Bit Flag, bit 11 (Language encoding flag (EFS)), should be
* used to indicate that both the header File Name and Comment fields
* are UTF-8 and, in this case, the Unicode Path and Unicode Comment
* extra fields are not needed and should not be created. Note that,
* for backward compatibility, bit 11 should only be used if the native
* character set of the paths and comments being zipped up are already
* in UTF-8. The same method, either general purpose bit 11 or extra
* fields, should be used in both the Local and Central Directory Header
* for a file.
*
* Utilisation rules:
* 1. This field shall never be created for names consisting solely of
* 7-bit ASCII characters.
* 2. On a system that already uses UTF-8 as system charset, this field
* shall not repeat the string pattern already stored in the Zip
* entry's standard name field. Instead, a field of exactly 9 bytes
* (70 75 05 00 01 and 4 bytes CRC) should be created.
* In this form with 5 data bytes, the field serves as indicator
* for the UTF-8 encoding of the standard Zip header's name field.
* 3. This field shall not be used whenever the calculated CRC-32 of
* the entry's standard name field does not match the provided
* CRC checksum value. A mismatch of the CRC check indicates that
* the standard name field was changed by some non-"up"-aware
* utility without synchronizing this UTF-8 name e.f. block.
*/
case 0x7075:
byte version = extraField[pos];
pos += 1;
uint nameCRC32 = BitConverter.ToUInt32(extraField, pos);
pos += 4;
CRC crcTest = new();
crcTest.SlurpBlock(bFileName, 0, bFileName.Length);
uint fCRC = crcTest.Crc32ResultU;
if (nameCRC32 == fCRC)
{
int charLen = blockLength - 5;
lf.Filename = Encoding.UTF8.GetString(extraField, pos, charLen);
}
break;
/*
* -Info-ZIP UNIX Extra Field (type 2):
* ==================================
*
* 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.
*
*/
case 0x7855: // Not Needed
break;
/*
* -Info-ZIP New Unix Extra Field:
* ====================================
*
* Currently stores Unix UIDs/GIDs up to 32 bits.
* (Last Revision 20080509)
*
* Value Size Description
* ----- ---- -----------
* (UnixN) 0x7875 Short tag for this extra block type ("ux")
* TSize Short total data size for this block
* Version 1 byte version of this extra field, currently 1
* UIDSize 1 byte Size of UID field
* UID Variable UID for this entry
* GIDSize 1 byte Size of GID field
* GID Variable GID for this entry
*
* Currently Version is set to the number 1. If there is a need
* to change this field, the version will be incremented. Changes
* may not be backward compatible so this extra field should not be
* used if the version is not recognized.
*
* UIDSize is the size of the UID field in bytes. This size should
* match the size of the UID field on the target OS.
*
* UID is the UID for this entry in standard little endian format.
*
* GIDSize is the size of the GID field in bytes. This size should
* match the size of the GID field on the target OS.
*
* GID is the GID for this entry in standard little endian format.
*
* If both the old 16-bit Unix extra field (tag 0x7855, Info-ZIP Unix2)
* and this extra field are present, the values in this extra field
* supercede the values in that extra field.
*/
case 0x7875: // Not Needed
break;
/* UNKNOWN */
case 0xe57a:
break;
default:
break;
}
blockPos += blockLength;
}
return(ZipReturn.ZipGood);
}
