Shop Item List Format

This document describes the shop item list block format used inside the Wasteland 1 GAME1 and GAME2 files.

It covers:

• how shop lists are located
• the outer block structure
• the rotating-XOR decoded payload
• the shop-item record layout

Scope

Shop item lists are not self-describing.

The game uses executable metadata from the executable to locate them.

See EXE Format for the structure and locations of those tables.

In the shipped Wasteland 1 data:

• GAME1 contains three actual shop item list blocks
• GAME2 contains one actual shop item list block
• the fourth GAME1 shop slot used by the executable tables points to the end of GAME1 and no block exists there

Observed offsets in the shipped files:

• GAME1: 157131, 157897, 158663
• GAME2: 171469

All multi-byte integer fields are little-endian.

The rotating-XOR algorithm used by the encrypted payload is documented separately:

• Rotating-XOR

Outer Block Layout

Each shop list block is fixed-size and begins with:

Offset	Type	Meaning
+0x00	char[4]	"msq0" in GAME1, "msq1" in GAME2
+0x04	u8	XOR byte 1
+0x05	u8	XOR byte 2
+0x06	u8[760]	Rotating-XOR encrypted payload

Total block size:

4 + 2 + 760 = 766 bytes = 0x2FE
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This fixed size matches the spacing of the real shop blocks in GAME1 and the final block length in GAME2.

Rotating-XOR Decoding

The 760-byte payload uses the rotating-XOR decoding described in Rotating-XOR.

Decode exactly 760 bytes after the two XOR bytes and verify that the final checksum equals endChecksum.

Decoded Payload Layout

The decoded shop-list payload is:

Offset	Size	Meaning
0x000	8	Fixed header bytes
0x008	94 * 8	Shop item records

The fixed decoded header bytes are identical across all real shop lists examined:

60 60 60 00 37 08 F8 39
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Their purpose is currently unknown.

Shop Item Record

Each shop item record is 8 bytes long:

Offset within record	Type	Meaning
+0x00	u16	Price
+0x02	u8	Stock
+0x03	u8	Packed type/flags byte
+0x04	u8	Capacity
+0x05	u8	Skill
+0x06	u8	Damage
+0x07	u8	Ammo item ID

Packed Type/Flags Byte

The byte at offset +0x03 is interpreted as:

itemType   = byte >> 3
lowFlags   = byte & 0x07
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Observed semantics in the shipped data:

• the upper 5 bits store the item type ID
• the low bits act as a demolition flag
• only values 0 and 1 were observed in the low 3 bits across all real shop entries

So the currently understood interpretation is:

demolition = (lowFlags == 1)
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with other low-bit combinations currently undocumented.

Record Count

Every real shop list examined contains exactly 94 records:

760 decoded bytes = 8-byte header + 94 * 8-byte items
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Unused entries still occupy their full 8-byte slots.

Validation Notes

Useful consistency checks when implementing a reader:

• the block must begin with "msq0" or "msq1"
• the total block size should be 0x2FE bytes
• rotating-XOR decoding must produce exactly 760 bytes
• the first 8 decoded bytes should match 60 60 60 00 37 08 F8 39
• the decoded payload should contain exactly 94 item records