139
edits
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Added some more comments to both headers
{
{
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:
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)
}
}
}
}
Blowfish encrypted: // Unencrypted, if DecryptFlags & 0x3 == 0
Blowfish encrypted: // Unencrypted, if (DecryptFlags & 0x3) == 0
{
{
uint128 Checksum;
uint128 Checksum;
uint32 GbxHeadersStart;
uint32 GbxHeadersStart; // Offset to the metadata section
if version < 15:
if version < 15:
uint32 DataStart;
uint32 DataStart; // If version >= 15: DataStart = HeaderMaxSize
if version >= 2:
if version >= 2:
{
{
===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]].