Fast Java interpreter for Brainfuck language with optimizations, memory management and multi dialect support
Brainfuck is an esoteric programming language created in 1993 by Urban Müller.
Notable for its extreme minimalism, the language consists of only eight simple commands, a data pointer and an
instruction pointer. While it is fully Turing complete, it is not intended for practical use, but to challenge and amuse
programmers. Brainfuck requires one to break commands into microscopic steps.
Learn more about Brainfuck here
- Fast interpreter with multiple dialects
- Dialect converter
- Swing-based GUI
- Executable JAR with command line interface
- Optimizations (clear loops, pre-calculating loop points, instruction batching)
If you run the packaged JAR directly, you get both CLI and GUI entry points:
java -jar Brainfuck4J-<version>.jar # GUI (Brainfuck Studio)
java -jar Brainfuck4J-<version>.jar run ... # CLIWhen using the Gradle project directly you can run:
./gradlew run # GUI (no args)
./gradlew run --args="run program.bf" # CLIExamples:
# Run a Brainfuck file with defaults (BRAINFUCK dialect, INTEGER memory, 30000 cells)
java -jar Brainfuck4J-<version>.jar run hello.bf
# Run with explicit dialect and memory settings
java -jar Brainfuck4J-<version>.jar run hello.bf --dialect BRAINFUCK --memory INTEGER --size 60000
# Convert between dialects
java -jar Brainfuck4J-<version>.jar convert input.bf output.troll --from BRAINFUCK --to TROLLSCRIPT
# List supported dialects and memory types
java -jar Brainfuck4J-<version>.jar list dialects
java -jar Brainfuck4J-<version>.jar list memoriesIf you want to depend on Brainfuck4J in your own project, use the Maven repository here:
https://mvnrepository.com/artifact/de.florianreuth/brainfuck4j
or
https://maven.florianreuth.de/#/snapshots/de/florianreuth/brainfuck4j (for snapshots)
The repository page includes the latest coordinates and setup instructions.
Jar builds can be downloaded from my build server: https://build.florianreuth.de/job/Brainfuck4J/
For accessing multiple dialects, the DialectType and Dialect classes can be used to convert between dialects or
define your own:
import de.florianreuth.brainfuck4j.dialect.Dialect;
import de.florianreuth.brainfuck4j.dialect.DialectType;
// Convert a Brainfuck program to TrollScript
final String trollScript = DialectType.BRAINFUCK.convert(
">++++++[<++++++>-]<.",
DialectType.TROLLSCRIPT
);
// Create a custom Brainfuck-like dialect
final Dialect customDialect = new Dialect(
">", // increment pointer
"<", // decrement pointer
"+", // increment cell
"-", // decrement cell
"[", // loop start
"]", // loop end
",", // input
"." // output
);The main entry point is the singleton Brainfuck4J.INSTANCE. You supply input/output streams, a memory implementation
and the (optionally pre-converted) program:
import de.florianreuth.brainfuck4j.Brainfuck4J;
import de.florianreuth.brainfuck4j.dialect.DialectType;
import de.florianreuth.brainfuck4j.memory.AbstractMemory;
import de.florianreuth.brainfuck4j.memory.MemoryType;
import de.florianreuth.brainfuck4j.instruction.Instruction;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.PrintStream;
import java.nio.charset.StandardCharsets;
import java.util.List;
// Original program in an arbitrary dialect
final String source = ">++++++[<++++++>-]<.";
final DialectType dialect = DialectType.BRAINFUCK;
// Normalize to pure Brainfuck if needed
String program = source;
if (dialect != DialectType.BRAINFUCK) {
program = dialect.convert(source, DialectType.BRAINFUCK);
}
// Optional input for the Brainfuck program
final byte[] inputBytes = new byte[0];
final InputStream in = new ByteArrayInputStream(inputBytes);
// Capture the output in memory (you can also pass System.out)
final ByteArrayOutputStream outBuffer = new ByteArrayOutputStream();
final PrintStream out = new PrintStream(outBuffer, true, StandardCharsets.UTF_8);
// Choose memory type and size
final MemoryType memoryType = MemoryType.INTEGER; // or BYTE, SHORT, ...
final int memorySize = 30000;
final AbstractMemory memory = memoryType.create(memorySize);
// Run the program and get the optimized instruction list
final List<Instruction> instructions = Brainfuck4J.INSTANCE.run(in, out, memory, program);
// Read output as string
final String output = outBuffer.toString(StandardCharsets.UTF_8);
System.out.println("Program output: " + output);
System.out.println("Instructions executed: " + instructions.size());Brainfuck4J.INSTANCE.run(...)performs parsing, optimizations and execution.InstructionandInstructionTypedescribe the optimized instruction stream.MemoryTypeandAbstractMemoryimplement the memory model (byte/short/int, size, bounds checking).DialectTypeandDialecthandle multi-dialect support and conversion.
All undocumented methods and classes are considered internal implementation details and may change.
This program / software was developed with the help of the following resources: