Trade Wars Export file format (TWX)
===================================

File version: 1

Copyright (C)2000 SWATH & ATTAC
The format is free to use by anyone.
For more information please contact us:

SWATH
Site:   http://www.swath.net
E-mail: support@swath.net

ATTAC
Site:   http://www.tw-attac.com
E-mail: tradewars@hotmail.com


The TWX file structure
----------------------

TWX_FILE_HEADER
n*TWX_SECTOR

n = The total number of sectors.


Data structures (presented in C/C++)
------------------------------------

All integers are signed and have the following sizes:

char  - 1 byte  (-1, 0 - +127)
short - 2 bytes (-32768 - +32767)
long  - 4 bytes (-2147483648 - +2147483647)

The binary stored integers should have TCP/IP network order.
Use functions like htons(), htonl(), ntohs() and ntohl()
to convert numbers from host byte order to network order
and vice versa.
Example: 0x12345678 should be stored as 0x12 0x34 0x56 0x78

typedef struct {		// Size: 256 bytes
	char id[4];		// File ID: "TWEX"
	long time_created;	// Timestamp when created (See TS)
	long ver;		// File version (See VE)
	long sectors;		// Total number of sectors
	long stardock;		// StarDock location (-1=Unknown)
	long cls0port_sol;	// Class 0 port: Sol (-1=Unknown)
	long cls0port_alpha;	// Class 0 port: Alpha Centauri (-1=Unknown)
	long cls0port_rylos;	// Class 0 port: Rylos (-1=Unknown)
	long crc32;		// Checksum (See CH)
	char reserved[220];	// Reserved for future use (Set to 0)
} TWX_FILE_HEADER;

typedef struct {		// Size: 96 bytes
	char info;		// Sector info (See SI)
	char navhaz;		// NavHaz percentage (0-100) (-1=Unknown)
	short reserved2;	// Reserved for future use (Set to 0)
	long sector_update;	// Timestamp from last sector update
				//  (0=Never updated) (See TS and USI)
	long ftrs;		// Fighters (-1=Unknown)
	short ftr_owner;	// Fighter owner (Reserved, set to -1)
	char ftr_type;		// Fighter type (1=Toll, 2=Offensive, 3=Defensive,
				//  0=Merchenary, -1=Unknown)
	char anom;		// Anomality (0=No, 1=Yes, -1=Unknown)
	short armids;		// Armid mines (-1=Unknown)
	short armid_owner;	// Armid owner (Reserved, set to -1)
	short limpets;		// Limpet mines (-1=Unknown)
	short limpet_owner;	// Limpet owner (Reserved, set to -1)
	long port_amt[3];	// Port amount [FOE] (-1=Unknown)
	char port_per[3];	// Port percentage [FOE] (0-100) (-1=Unknown)
	char warps;		// # of warp sectors (-1=Unknown)
	long warp_sect[6];	// Warp sectors
	long port_update;	// Timestamp from last port update
				//  (0=Never updated) (See TS and USI)
	long density;		// Sector density (-1=Unknown)
	char reserved[24];	// Reserved for future use (Set to 0)
} TWX_SECTOR;


Extra field information
-----------------------

=== TS ===
A standard timestamp like the one returned from the C function time().
The number of seconds elapsed since midnight (00:00:00), January 1, 1970,
coordinated universal time.

=== VE ===
The file version.
All helpers should control the file version and if you don't support
the version you should not import the file. If you support a certain
version you should support all previous versions too since they will
be a subset of the later version.

=== CH ===
The 32-bit checksum is calculated using XOR. Look at the file as
a big array of 4 byte longs. XOR all those together with the crc32
field set to 0. The result should be written to the crc32 field.
When checking the checksum you simply perform the XOR for the
whole file including the crc32 field. The result should be 0 (zero).
If not, the file is corrupted and should not be imported.

=== SI ===
0-9 = Port class 0-9
10  = Empty (no port)
11  = Unexplored
12  = Port destroyed
+16 = Port under construction (16+class)
Examples:
 2 = Class 2 port (BSB)
18 = Class 2 port (BSB) under construction

=== USI ===
This section describes when to update the timestamps for a sector.
It is important to follow these rules since it would affect
the merge of sector info when doing an import of a TWX file.
Initially both sector_update and port_update should be set to 0.

Unexplored sector (info == 11):
-If you update the sector warps when info=11, that means that you are
 entering ZTM data. When importing an unexplored sector the timestamp
 should not be used since all sector warps are correct and should be merged.
 When updating the sector with known data (info != 11), you should overwrite
 the sector and write a new timestamp.

Visited, Scanned or E-Probed sector (info != 11):
-Now, the complete sector info is revealed. Update the sector_update timestamp.
 Only explored sectors that are newer can overwrite this kind of sector.
 Note that the port data should be handled separately, using port_update.

When you visit a port in a sector or get a port report:
-Now, you will get the complete port info.
 Update the port_update timestamp.

CIM download:
-A CIM download does only contain known sectors.
 Therefore you will only get new port info.
 (All the sector warps are already known)
 If new port info is stored, update the port_update timestamp.