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ZenGin Archives

ZenGin archives (ZEN files) contain generic data for use with the ZenGin. Most archives store key-value pairs organized into objects, similar to JSON. Archives have three different encodings: binary archives store unannotated bytes, safe binary archives store binary data annotated with field types and names and ascii archives contain a human-readable form of the same data stored in safe binary archives.

General Concepts

A basic archive file might look like this.

Example ZEN archive (ASCII)
ZenGin Archive
ver 1
saveGame 0
date 17.9.2002 15:21:1
user mario.roeske
objects 7        
[% oCWorld:zCWorld 64513 0]
    [VobTree % 0 0]
        [% zCVob 39168 1]
            bbox3DWS=rawFloat:334.003906 -443.912476 -7493.55371 2734.00391 1956.08765 -5093.55371 
            trafoOSToWSPos=vec3:1534.00403 756.087585 -6293.55371
            [visual % 0 0]
            [ai % 0 0]

At the beginning of the file, the header is defined. It consists of two parts, the first one being the same across all encoding and the second being specific to the encoding used. The data content of the file starts right after the second END. The first line of the file's content, [% oCWorld:zCWorld 64513 0], marks the start of a new object while the last line, [] marks the end of an object.

Each object can contain multiple entries alongside other objects. Each entry has a name, a type and a value. This only applies to ascii and safe binary encodings.

The header of ZEN archives consists of two parts. The first has the same structure for every archive and the second differs between encodings. The first part of the header looks like this. Variable elements of the header have been replaced by <...> placeholders.

Example ZEN archive header
ZenGin Archive
ver 1
saveGame <issave>
date <timestamp>
user <username>

Line breaks denote only one newline (\n) character. The <archiver> is a string value, being either zCArchiverGeneric or zCArchiverBinSafe, in reference to the names of the ZEN archive parser classes in the original source code. <encoding> specifies the type of archive in the file. It is either ASCII (for ascii encoded archives), BINARY (for binary encoded archives) or BIN_SAFE (for safe binary encoded archives). If the archive is a save game file <issave> is set to 1, otherwise it is 0. <timestamp> denotes the date and time the archive was created. It follows the strptime format %d.%m.%Y %H:%M:%S. <username> is the name of the user (originally the windows account name) the archive was created by. For save games this contains the name of the user who saved the game. Refer to the example above for a filled-out version of the header.

The encoding-specific headers follow directly after the END\n line of the first header as can be seen in the example.


Objects in ZEN archives consist of an object name, a class name, a version identifier and an index. The object name is used to describe a unique sub-object of another while the class name is used to identify the type of the object. A ZEN archive object [visual zCParticleFX 0 6] describes a specific sub-object visual of type zCParticleFX meaning it has a set of entries consistent with the definition of a zCParticleFX. Objects without an object name just contain a % instead. Objects always end with [].


This behavior can be seen in the example above. Every object with the class name zCVob has the same set of entries as shown in the example.


The object name must be unique within each sub-object. A ZEN archive like this is invalid.

Text Only
[% oCWorld:zCWorld 64513 0]
    [VobTree % 0 0]
    [VobTree % 0 0]

Class names originally referenced a specific class in C++-code. These classes were polymorphic so an object with a class name zCVobLight:zCVob contains both entries of type zCVob and zCVobLight. The entries of the super-class always precede the entries of the subclass, so the zCVobLight:zCVob would first contain all entries of zCVob and then all entries of zCVobLight. Objects without a class name just contain a % instead.


Class and object names may not contain spaces.

The version of an object is a 32-bit unsigned number which denotes the version of the bottom-most subclass. The version of object [% oCMobInter:oCMOB:zCVob 35585 0] would be 35585. This version, however, only refers to the oCMobInter-part.


This leads to issues when trying to determine whether an object uses the Gothic or the Gothic II definition. If the structure for oCMobInter did not change between the games, the version will be the same. This is not necessarily true for zVob though. Its definition might have changed but this change is not reflected in the version field of the object.

The index field of the object is a 32-bit unsigned number which increments for every object with a class name in the archive. In the example this can be seen with the objects [% oCWorld:zCWorld 64513 0] and [% zCVob 39168 1]. Objects without a class name have an index of 0.


The concept of entries only really applies to archives with ascii or safe binary encoding. An entry originally represented a field in a C++-class which defined an object. For this reason, each entry has a name, a type and a value. The following entry types are supported:

Type Name Type ID1 Description
string 1 ISO-8859-1 encoded text
int 2 A 32-bit signed integer
float 3 An IEEE 754 floating-point number
byte 4 An 8-bit unsigned integer
word 5 An 16-bit unsigned integer
bool 6 An boolean value2
vec3 7 A set of 3 IEEE 754 floating-point numbers
color 8 A set of 4 8-bit unsigned integers
raw 9 A set of an arbitrary amount of 8-bit unsigned integers
rawFloat 16 A set of an arbitrary amount of IEEE 754 floating-point numbers
enum 17 A 32-bit unsigned integer3
hash 18 A 32-bit unsigned integer; specific to the safe binary encoding


ASCII-archives are human-readable ZEN archives, comparable to JSON. Contrary to its name, the file is not actually using the ASCII text encoding. Rather these files are encoded in ISO-8859-1 or alternatively Windows-1252 (because the characters used are encoded identically).

ASCII ZEN-archives use a line-based format. Every line after the header contains exactly one object start statement, entry statement or object end token. Leading whitespace is ignored.


The encoding specific header for the ASCII-encoding looks like this. Variable elements of the header have been replaced by <...> placeholders.

Text Only
objects <count>

<count> denotes the total number of objects in the archive. Refer to the example above for a filled-out version of the header.


As stated above, objects in ASCII-ZENs start with a line [% oCWorld:zCWorld 64513 0] defined as [<object name> <class name> <version> <index>]. This is explained further in the section about objects.


Entries in ASCII-ZENs follow the format <name>:<type>=<value> where <name> is a C++ identifier, <type> is one of the type names mentioned in the entries section with the exclusion of the hash type. <value> depends on the given type. It has the following formats:

Type Name Format Regex Example
string An unlimited number of characters excluding newline characters ^[^\n\r]* field=string:This is a string
int A decimal 32-bit integer ^[+-]?\d+$ field=int:199
float A decimal floating point value with decimal separator . ^[+-]?(\d+\.)?\d+$ field=float:-1.0
byte A decimal 8-bit unsigned integer ^\d{1,3}$ field=byte:255
word A decimal 16-bit unsigned integer ^\d+$ field=word:1001
bool A decimal 1-bit integer ^[01]$ field=bool:1
vec3 A set of three floating point values ^[+-]?(\d+\.)?\d+ [+-]?(\d+\.)?\d+ [+-]?(\d+\.)?\d+$ field=vec3:1.0 -0.1 +100
color A set of four 8-bit unsigned integers ^\d{1,3} \d{1,3} \d{1,3} \d{1,3}$ field=color:100 0 255 12
raw An unlimited number of hexadecimal bytes ^([0-9A-Fa-f]{2})* field=raw:0fac3256b1
rawFloat An unlimited number of floating point values ^([+-]?(\d+\.)?\d+ )* field=rawFloat:1.0 -100
enum A decimal 32-bit unsigned integer ^\d+$ field=enum:10


Binary archives are little more than containers for raw bytes. They don't actually contain key-value pairs.


The encoding specific header for the Binary-encoding is the same as that of the ascii encoding. Variable elements of the header have been replaced by <...> placeholders.

Text Only
objects <count>

<count> denotes the total number of objects in the archive.


Objects in binary ZENs don't work like they do in the ascii and safe binary encodings. No object end marker is stored and the beginning of an object does not follow the same format.

Binary archive object begin structure
#pragma pack(push, 1)
struct zen_object_begin {
    uint32_t object_size; //the size of the object in bytes, including the header.
    uint16_t version; // the *version* number of the object
    uint32_t index; // the *index* of the object
    char* object_name; // The *name* of the object including a null-termination character
    char* class_name; // The *class* of the object including a null-termination character
#pragma pack(pop)


Binary ZENs just contains packed bytes with no added type annotations. This makes it very difficult to determine the layout of structures within it without having access to the original source code.

To read an integer from a binary ZEN for example, the next four bytes are read in literally like this (assuming a little-endian architecture).

Binary archive entry read scalar example
int32_t zen_binary_read_int(FILE* fp) {
    int32_t value = 0;
    fread(&value, sizeof(value), 1, fp);
    return value;


On big-endian architectures, the value read would have to be byte-swapped after reading.

This method of extracting values from binary archives is also used for aggregate types, like the vec3. Instead of reading just one float from the input, three are read like this.

Binary ZEN entry read vector example
typedef struct vec3 {
    float x;
    float y;
    float z;
} vec3_t;

vec3_t zen_binary_read_int(FILE* fp) {
    vec3_t value;
    fread(&value.x, sizeof(float), 1, fp);
    fread(&value.y, sizeof(float), 1, fp);
    fread(&value.z, sizeof(float), 1, fp);
    return value;

Refer to the following table for type sizes.

Type Name C-equivalent Byte Count
string char[] 1 * n
int int32_t 4
float float 4
byte uint8_t 1
word uint16_t 2
bool uint8_t 1
vec3 struct { float, float, float } 4 * 3
color struct { uint8_t, uint8_t, uint8_t, uint8_t } 1 * 4
raw uint8_t[] 1 * n
rawFloat float[] 4 * n
enum uint32_t 4

Safe Binary

Safe binary archives store binary values annotated with field types and names. They are the most prevalent types of archives and also the ones in which world data is stored. The values of entries as well as their prefixes are stored in a packed binary format. This encoding is not fully reverse-engineered.


The header of safe binary archives is also binary and has the following structure.

Safe binary archive header structure
#pragma pack(push, 1)
struct zen_binsafe_header {
    uint32_t bs_version; // A separate version identifier for the version of the safe binary encoding used.
    uint32_t object_count; // The total number of objects in the archive
    uint32_t hash_table_offset; // The offset of the hash table from the beginning of the file in bytes; discussed below.
#pragma pack(pop)

In addition to the secondary header, safe binary archives also contain a so-called hash table4 which stores field name information. The hash table is a binary structure as well; it looks like this.

Safe binary ZEN hash table structure
#pragma pack(push, 1)
struct zen_binsafe_hashtable_entry {
    uint16_t name_length; // The length of the name string at the end of the structure
    uint16_t insertion_index; // The index of this entry in the hashtable `entries` member array
    uint32_t bucket_index; // The bucket index of this entry. See below.
    char name[]; // The name of the entry. This name is the field name of the entry as explained below

struct zen_binsafe_hashtable {
    uint32_t size; // The number of entries in the hash table. Corresponds with the length of the `entries` member array.
    zen_binsafe_hashtable_entry entries[]; // An array of all hash table entries; unordered.
#pragma pack(pop)

The bucket_index is calculated using the following algorithm:

/* The capacity of the hash table was always the same: 0x61 buckets. */

int zen_calculate_bucket_index(char const* key) {
    int hash = 0;

    while (*key != '\0') {
       hash = hash * 0x21 + (int) *key;
       key += 1;



In safe binary ZENs, objects are handled in almost the same way entries are. Objects definitions are preceded by the string type identifier \x01 and a 16-bit string length value. The value of this string is the same as the object definition for ASCII-ZENs: Objects start with a line [% oCWorld:zCWorld 64513 0] defined as [<object name> <class name> <version> <index>]. This is explained further in the section about objects.

A full object definition might look like this: \x01\x1B\x00[% oCWorld:zCWorld 64513 0].


Note that objects are never preceded by a field name like entries are.


Every entry in safe binary ZENs is preceded by a field name index and a type identifier including a length if applicable. File name indexes start with a \x12 which is followed by a 32-bit unsigned integer, indicating an index into the hash table discussed above. The name of the hash table entry at that index is the name of the field.

A boolean entry in this format might look like \x12\x01\x00\00\x00\x06\x01\x00\x00\x00. It hashtable index is 1 and its value is true. Type IDs are always uint8_ts and hashtable indices are always uint32_ts.

Reference the table below for all types in safe binary archives.

Type Name Type ID Has Length? C-equivalent Byte Count
string 1 Yes char[] 1 * n
int 2 No int32_t 4
float 3 No float 4
byte 4 No uint8_t 1
word 5 No uint16_t 2
bool 6 No uint32_t 4
vec3 7 No struct { float, float, float } 4 * 3
color 8 No struct { uint8_t, uint8_t, uint8_t, uint8_t } 1 * 4
raw 9 Yes uint8_t[] 1 * n
rawFloat 16 Yes float[] 4 * n
enum 17 No uint32_t 4


Entries with a length prefix, are encoded like this: \x12\x01\x00\00\x00\x01\x0D\x00Hello, world!. It hashtable index is 1, its length is 0x0D and its value is Hello, World!. Note that the length is always a uint16_t and always follows directly after the type ID.

  1. The type index is relevant only for safe binary encoded archives. 

  2. The actual representation of this value changes between encodings. With the safe binary encoding a boolean value is represented as a 32-bit unsigned integer while it is represented as an 8-bit integer in the binary encoding. 

  3. Enums represent an actual enumeration value in C++-code. 

  4. The origin of that name is unknown. It has been used in ZenLib to describe this element of the format.