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Line 147: − + − + − uint32 DataStart;+ − uint32 GbxHeadersSize;+ − uint32 GbxHeadersComprSize;+ − uint128 unused;+ − uint32 FileSize;+ − uint128 unused;+ − SAuthorInfo;+ − int32 FolderIndexParent;+ − string FolderName;+ − int32 FolderIndex;+ − string FileName;+ − uint32 unknown;+ − uint32 UncompressedSize;+ − uint32 CompressedSize;+ − uint32 Offset;+ − uint32 [[Class IDs|classID]];+ − if version >= 17:+ − uint32 Size;+ − if version >= 14:+ − uint128 Checksum;+ − uint64 Flags;+ + + + + + + + + + + + + + Line 179:
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→Header versions 6+: Updated a comment
{
{
uint128 headerMD5;
uint128 headerMD5;
uint32 metaDataOffset;
uint32 gbxHeadersStart; // offset to metadata section
uint32 dataOffset;
uint32 dataStart;
if version >= 2:
if version >= 2:
{
{
uint32 metaDataUncompressedSize;
uint32 gbxHeadersSize;
uint32 metaDataCompressedSize;
uint32 gbxHeadersComprSize;
}
}
if version >= 3:
if version >= 3:
{
{
uint256 ContentsChecksum; // Checksum Sha256 of the pack contents starting at next byte
uint256 ContentsChecksum; // Checksum Sha256 of the pack contents starting at next byte
uint32 DecryptFlags; // 0x1 = IsHeaderPrivate, 0x2 = IsCrypted(?), 0x4 = IsDataPrivate, 0x8 = IsImpostor
struct SHeaderFlagsUncrypt
{
uint32 IsHeaderPrivate : 1;
uint32 UseDefaultHeaderKey : 1;
uint32 IsDataPrivate : 1;
uint32 IsImpostor : 1;
uint32 __Unused__ : 28;
};
if (version >= 15)
if (version >= 15)
uint32 HeaderMaxSize; // 0x4000 = Small (16 KB), 0x100000 = Big (1 MB), 0x1000000 = Huge (16 MB)
uint32 HeaderMaxSize; // 0x4000 = Small (16 KB), 0x100000 = Big (1 MB), 0x1000000 = Huge (16 MB)
if (version >= 7)
if (version >= 7)
{
{
SAuthorInfo AuthorInfo; // uint32 version = 0, string login, string nick, string zone, string extra
struct SAuthorInfo
{
uint32 Version;
string Login;
string Nick;
string Zone;
string ExtraInfo;
};
if (version < 9)
if (version < 9)
{
{
if (version >= 13)
if (version >= 13)
string DownloadUrl;
string DownloadUrl;
uint64 CreationDate;
uint64 CreationDate; // Win32 FILETIME structure
string Comment;
string Comment;
if (version >= 12)
if (version >= 12)
string TitleID;
string TitleID;
}
}
string UsageSubDir; // to known the kind of pack it is
string UsageSubDir; // to known the kind of pack it is
string CreationBuildInfo;
string CreationBuildInfo;
uint128 unused;
uint128 unused;
if (version >= 10)
if (version >= 10)
}
}
}
}
Blowfish encrypted: // Unencrypted, if DecryptFlags & 0x3 == 0
Blowfish encrypted: // Unencrypted if neither SHeaderFlagsUncrypt.IsHeaderPrivate nor SHeaderFlagsUncrypt.UseDefaultHeaderKey are set
{
{
uint128 Checksum;
uint128 Checksum;
uint32 GbxHeadersStart;
uint32 GbxHeadersStart; // Offset to the metadata section
if version < 15:
if version < 15:
uint32 DataStart; // If version >= 15: DataStart = HeaderMaxSize
if version >= 2:
if version >= 2:
{
{
uint32 GbxHeadersSize;
uint32 GbxHeadersComprSize;
}
}
if version >= 14:
if version >= 14:
uint128 unused;
if version >= 16:
if version >= 16:
uint32 FileSize;
if version >= 3:
if version >= 3:
uint128 unused;
if version == 6:
if version == 6:
SAuthorInfo;
uint32 Flags;
uint32 Flags;
uint32 NumFolders;
uint32 NumFolders;
FolderDesc Folders[NumFolders]
FolderDesc Folders[NumFolders]
{
{
int32 FolderIndexParent;
string FolderName;
}
}
uint32 NumFiles;
uint32 NumFiles;
FileDesc Files[NumFiles]
FileDesc Files[NumFiles]
{
{
int32 FolderIndex;
string FileName;
uint32 unknown;
uint32 UncompressedSize;
uint32 CompressedSize;
uint32 Offset;
uint32 [[Class IDs|classID]];
if version >= 17:
uint32 Size;
if version >= 14:
uint128 Checksum;
struct SFileDescFlags
{
uint32 IsHashed : 1;
uint32 PublishFid : 1;
uint32 Compression : 4;
uint32 IsSeekable : 1;
uint32 _Unknown_ : 1;
uint32 __Unused1__ : 24;
uint32 DontUseDummyWrite : 1;
uint32 OpaqueUserData : 16;
uint32 PublicFile : 1;
uint32 ForceNoCrypt : 1;
uint32 __Unused2__ : 13;
};
}
}
}
}
===Data===
===Data===
The content of each file starts at Header.dataOffset + FileDesc.offset in the .pak file. First, an 8-byte plaintext IV is read. Then, FileDesc.compressedSize bytes are read and decrypted using Blowfish in CBC mode, using the same key that was used to decrypt the header. If FileDesc.flags & 0x7C is not zero, the file is compressed and should be decompressed using zlib deflate after decryption (it will end up at FileDesc.uncompressedSize bytes).
The content of each file starts at Header.dataStart + FileDesc.offset in the .pak file. From version 15, the data block starts at HeaderMaxSize. First, an 8-byte plaintext IV is read. Then, FileDesc.compressedSize bytes are read and decrypted using Blowfish in CBC mode, using the same key that was used to decrypt the header. If FileDesc.flags & 0x7C is not zero, the file is compressed and should be decompressed using zlib deflate after decryption (it will end up at FileDesc.uncompressedSize bytes).
The type of the file can be found from the extension in the name, or, if this is not available (many file names are actually just hashes), from the [[Class IDs|class ID]].
The type of the file can be found from the extension in the name, or, if this is not available (many file names are actually just hashes), from the [[Class IDs|class ID]].