ChipWizard save format notes

chipwizard.txt

ChipWizard save format notes:
* stored in save.dat base64-encoded and zlib compressed
* multi-byte integers are little-endian

4-byte header at start of file: 0xEA 0x03 0x00 0x00

120 bytes of data for layout
* 4 bytes for each cell, 5 rows × 6 columns
* starts at lower-left corner, proceeds to the right, wrapping to the next row above

byte 1: bit field for components
  0x01: metal
  0x02: n-type
  0x04: p-type
  0x08: capacitor
  0x10: via
  0x20: transistor type (set by n-type, cleared by p-type, persists after deletion)
  0x40 & 0x80: unused
byte 2: metal connections, only lowest 4 bits used
  0x01: right
  0x02: top
  0x04: left
  0x08: bottom
byte 3: n-type connections (same values as metal)
byte 4: p-type connections (same values as metal)


Examples in binary:
metal, none:    00000001 00000000 00000000 00000000
metal, right:   00000001 00000001 00000000 00000000
metal, top:     00000001 00000010 00000000 00000000
metal, left:    00000001 00000100 00000000 00000000
metal, bottom:  00000001 00001000 00000000 00000000
n-type, none:   00100010 00000000 00000000 00000000
n-type, right:  00100010 00000000 00000001 00000000
n-type, top:    00100010 00000000 00000010 00000000
n-type, left:   00100010 00000000 00000100 00000000
n-type, bottom: 00100010 00000000 00001000 00000000
p-type, none:   00000100 00000000 00000000 00000000
p-type, right:  00000100 00000000 00000000 00000001
p-type, top:    00000100 00000000 00000000 00000010
p-type, left:   00000100 00000000 00000000 00000100
p-type, bottom: 00000100 00000000 00000000 00001000
capacitor:      00001000 00000000 00000000 00000000 (exclusive with silicon)
via:            00010000 00000000 00000000 00000000 (can only be placed on silicon)

p-type, L&R:         00000100 00000000 00000000 00000101  (p-type, right | p-type, left)
PNP, base on top:    00100110 00000000 00000010 00000101  (p-type, right | p-type, left | n-type, up)

n-type, L&R:         00100010 00000000 00000101 00000000  (n-type, right | n-type, left)
NPN, base on bottom: 00000110 00000000 00000101 00000010  (n-type, right | n-type, left | p-type, up)

The transistor type flag is used to distinguish between transistors that have the same connection layout:
PNP, base on top and bottom:  00000110 00000000 00000101 00001010
NPN, base on left and right:  00100110 00000000 00000101 00001010
It gets set when dragging over a cell with n-type silicon selected.


This is followed by 0x01 and 16 more bytes if there's a selection, or just 0x00 if not
selection format:
  u4: lower-left corner x
  u4: lower-left corner y
  u4: width
  u4: height

dump_chipwizard.py

#!/usr/bin/env python3
"""Reads ChipWizard solutions from `save.dat` and pretty-prints them."""

import base64
import io
import struct
import sys
import zlib

for line in sys.stdin:
    key, _, string = line.partition(" = ")
    if not key.startswith("Volgograd.Solution"):
        continue
    data = zlib.decompress(base64.b64decode(string.strip()))
    stream = io.BytesIO(data)
    print(f"{key}:")
    # check header
    assert struct.unpack("<I", stream.read(4))[0] == 1002
    rows = []
    for r in range(5):
        row = []
        for c in range(6):
            cell = stream.read(4)
            row.append(cell)
        rows.append(row)
    if stream.read(1)[0]:
        selection = True
        x, y, width, height = struct.unpack("<4I", stream.read(16))
    else:
        selection = False

    # print in reverse order, to match the layout in-game
    for row in rows[::-1]:
        for cell in row:
            print(" ".join([f"{byte:08b}" for byte in cell]), end="  ")
        print()
    if selection:
        print(f"Selection: {x=}, {y=}, {width=}, {height=}")
    print()