FROM gcc:10.1

RUN apt update && apt install -y xboard

ENTRYPOINT []

{

"name": "cpp-chess",

"dockerFile": "Dockerfile",

"extensions": [

"ms-vscode.cpptools"

]

}

**/*~

**/*.o

**/*.d

src/error.txt

**/*.dat

src/error.txt

{

"configurations": [

{

"name": "Linux",

"includePath": [

"${workspaceFolder}/**"

],

"defines": [],

"compilerPath": "/usr/bin/g++",

"cStandard": "c11",

"cppStandard": "c++20",

"intelliSenseMode": "clang-x64"

}

],

"version": 4

}

{

"git.ignoreLimitWarning": true,

"files.associations": {

"array": "cpp",

"atomic": "cpp",

"hash_map": "cpp",

"hash_set": "cpp",

"strstream": "cpp",

"*.tcc": "cpp",

"bitset": "cpp",

"cctype": "cpp",

"chrono": "cpp",

"clocale": "cpp",

"cmath": "cpp",

"codecvt": "cpp",

"complex": "cpp",

"condition_variable": "cpp",

"csignal": "cpp",

"cstdarg": "cpp",

"cstddef": "cpp",

"cstdint": "cpp",

"cstdio": "cpp",

"cstdlib": "cpp",

"cstring": "cpp",

"ctime": "cpp",

"cwchar": "cpp",

"cwctype": "cpp",

"deque": "cpp",

"forward_list": "cpp",

"list": "cpp",

"unordered_map": "cpp",

"unordered_set": "cpp",

"vector": "cpp",

"exception": "cpp",

"rope": "cpp",

"slist": "cpp",

"fstream": "cpp",

"functional": "cpp",

"future": "cpp",

"initializer_list": "cpp",

"iomanip": "cpp",

"iosfwd": "cpp",

"iostream": "cpp",

"istream": "cpp",

"limits": "cpp",

"memory": "cpp",

"mutex": "cpp",

"new": "cpp",

"numeric": "cpp",

"optional": "cpp",

"ostream": "cpp",

"ratio": "cpp",

"shared_mutex": "cpp",

"sstream": "cpp",

"stdexcept": "cpp",

"streambuf": "cpp",

"string_view": "cpp",

"system_error": "cpp",

"thread": "cpp",

"cinttypes": "cpp",

"tuple": "cpp",

"type_traits": "cpp",

"typeindex": "cpp",

"typeinfo": "cpp",

"utility": "cpp",

"valarray": "cpp",

"*.ipp": "cpp",

"variant": "cpp",

"string": "cpp",

"algorithm": "cpp"

}

}

FROM gcc:10.1

RUN apt update && apt install -y xboard

WORKDIR /chess/src

ADD src /chess/src

ARG DB=

ARG XB=

RUN DB=$DB XB=$XB make

ENTRYPOINT ["./chess"]

run: build

docker run --rm -it --init --volume $(shell pwd)/tables:/chess/src/tables:rw --volume $(shell pwd)/xboard_commands:/chess/src/xboard_commands:rw --name chess chess

run_db: build_db

docker run --rm -it --init --volume $(shell pwd)/tables:/chess/src/tables:rw --volume $(shell pwd)/xboard_commands:/chess/src/xboard_commands:rw --name chess_db chess_db

run_xb: build_xb

docker run --rm -i --init --volume $(shell pwd)/tables:/chess/src/tables:rw --volume $(shell pwd)/xboard_commands:/chess/src/xboard_commands:rw --name chess_xb chess_xb

run_db_xb: build_db_xb

docker run --rm -i --init --volume $(shell pwd)/tables:/chess/src/tables:rw --volume $(shell pwd)/xboard_commands:/chess/src/xboard_commands:rw --name chess_db_xb chess_db_xb

build_all: build build_db build_xb build_db_xb

build:

docker build --tag chess .

build_db:

docker build --build-arg DB=DB --tag chess_db .

build_xb:

docker build --build-arg XB=XB --tag chess_xb .

build_db_xb:

docker build --build-arg DB=DB --build-arg XB=XB --tag chess_db_xb .

TLDR: Don't waste your time by looking here.

Source code (C++98) for the program made in my master thesis: Generation and compression of endgame tables in chess with fast random access using OBDDs.

When I wrote this program I made use of several optimizations that we're based on how the compiler I was using happened to behave.

In some cases this was a deliberate (but bad) choice. In most cases I didn't know better.

These are some of the mistakes that I've been hit by:

* I assumed that a `char` was an unsigned 8 bit integer.

* I assumed that I could write to one union member and read the corresponding bits from another union member

A few times I've tried to rectify the errors and make the program work again.

But this is hard work with 35k lines of poorly documented code :-/

Currently large parts of it is working (in a dockerized build environment) but there are still significant problems.

Known bugs

* Some short versions of commands causes crash (e.g. "ctfi ..." instead of "construct from table index ...")

* With retrograde construction many (all?) invalid positions are stored as draw (-125) instead of illegal (-128). This reduces how much the tables can be compressed as OBDDs.

* The 5 piece KPPKP endgame cannot be constructed as it contains a position with a depth to mate of 127 (`8/8/8/8/1p2P3/4P3/1k6/3K4 w - - 0 1`). This cannot fit in the `uint8_t` as values -124 and below are reserved.

* When compiled against XBoard an error is logged when quitting the program (`free(): double free detected in tcache 2`)

* Retrograde construction of KBNKP fails for a position with a pawn at an invalid square:

* The endgames tables that are built seems to be correct. At least they are correct for some longest mates for 5 piece endgames ([test.com](src/test.com))

* The chess engine can be used by xboard (tested with version 4.9.1). As command use `make run_xb` using the root of this repository as folder. This assumes you have docker installed. Maybe you should run `make run_xb` first to prebuild the image.

import sys

def main(fn1, fn2, max_count):

with open(fn1, "rb") as f:

data1 = f.read()

with open(fn2, "rb") as f:

data2 = f.read()

for i, (b1, b2) in enumerate(zip(data1, data2)):

if b1 != b2:

print("{} != {} at index {}".format(ord(b1), ord(b2), i))

max_count -= 1

if not max_count:

break

main(sys.argv[1], sys.argv[2], int(sys.argv[3] if len(sys.argv) > 3 else 10))