D2R Save file reader/editor (OFFLINE only)

This is a D2S file (Diablo Save file) reader and editor. Implemented completely in C++ - purely out of curiosity and as a hobby for reading and editing stats of OFFLINE characters.

TL;DR

How to use the tool: Usage

What can this tool do:

1. Read a .d2S save file and print out character attributes.
2. Edit the .d2S file with any attribute values desired.

What this tool cannot do:

1. Edit any online character.
2. Add/edit any specific skills. 3:$ . Add/edit any specific items.

Save file format

A D2S file consists of a 765 byte header followed by the character attributes, skills and then items.

Byte	Length	Description
0	4	Magic (0xaa55aa55)
4	4	Version (0x61 for D2R)
8	4	File size
12	4	Checksum
...	...	...
765	2	Stats begin (0x6667)

Details of the save file format are courtesy of: https://github.com/krisives/d2s-format

Stats encoding

Actual stats start from byte 767 in the file. The format of the attributes is:

attribute_id (9 bits)	attribute_value (variable length)

Attribute lengths are variable and are defined as:

         10, // Strength
         10, // Energy
         10, // Dex
         10, // Vit
         10, // Stats left
         8, // Skills left
         21, // HP
         21, // Max HP
         21, // Mana
         21, // Max Mana
         21, // Stamina
         21, // Max stamina
         7, // Level
         32, // Experience,
         25, // Gold
         25 // Stashed Gold

Attribute IDs are encoded in 9 bits and the values are:

         "Strength" = 0,
         "Energy" = 1,
         "Dexterity" = 2,
         "Vitality" = 3,
         "Stats left" = 4,
         "Skills left" = 5,
         "HP" = 6,
         "Max HP" = 7,
         "Mana" = 8,
         "Max Mana" = 9,
         "Stamina" = 10,
         "Max Stamina" = 11,
         "Level" = 12,
         "Experience" = 13,
         "Gold" = 14,
         "Stash Gold" = 15

The end of the attribute section is determined by the presence of an "invalid" attribute_id - 9 bits of all 1s (0x1ff or 511)

Reading the stats

One important thing to note is that each byte in the stats section is actually bit-reversed and stored in the file. For example, if the bit-stream in the file is : 00000000 00011110 00001000 10010000, it needs to be interpreted as:

1. Reverse the bits: 00000000 01111000 00010000 00001001
2. Read 9 bits:

00000000 01111000 00010000 00001001
^        ^

Gives: 000000000

3. Reverse the 9 bits: 000000000 gives the attribute_id: 0 - Strength
4. Strength value is 10 bits, so read the next 10 bits:

00000000 01111000 00010000 00001001
          ^         ^

gives: 1111000000

5. Reverse the 10 bits: 0000001111 : 15
6. Read the next 9 bits for the next attribute:

00000000 01111000 00010000 00001001
                     ^        ^

gives: 100000000

7. Reverse the 9 bits read: 000000001 gives the attribute_id: 1 - Energy
8. Read the next 10 bits... and so on, until we find the attribute_id: 111111111 or 0x1ff

Modfying the stats.

Stats that are to be modified can be put in the edit.cfg file:

Strength=512
Energy=230
Dexterity=413
Vitality=872
Stats left=14
Skills left=14
HP=500
Max HP=500
Mana=500
Max Mana=500
Stamina=199
Max Stamina=199
Level=1
Experience=0
Gold=8000
Stash Gold=1000

Values which are 0 remain unmodified, else the value present in the edit.cfg file is added to the character.

Usage

1. Compile the binary: g++ d2r_edit.cc util.cc char.cc -o d2r
2. Invoke the tool: ./d2r <d2s_file_path>

Example:

$ bin/d2r ../Diablo\ II\ Resurrected/N_one.d2s
...
...
...
----------------------------
Processed 54 bytes
----------------------------
Name: N_one
Class: Necromancer
----------------------------
Strength: 512
Energy: 512
Dexterity: 512
Vitality: 0
Stats left: 14
Skills left: 14
Max HP: 500
Mana: 500
Max Mana: 500
Stamina: 199
Max Stamina: 199
Level: 1
Experience: 104214
Gold: 8000
Stash Gold: 1000
----------------------------