dtoma · December 29, 2016 07:05 · dtoma · Dec 27, 2016
diff --git a/bf.cpp b/bf.cpp
 #include <cstdio>
 #include <functional>
 #include <unordered_map>
 #include <vector>

 // Notes
 // [some brainfuck fluff by daniel b cristofani](http://www.hevanet.com/cristofd/brainfuck/)
 // [The Epistle to the Implementors](http://www.hevanet.com/cristofd/brainfuck/epistle.html)
 // [The BrainFuck Compiler Collection](https://github.com/Sirflankalot/bfcc)

 // TODO
 // - [ ] Parser
 // - [ ] Tests
 // - [ ] Graphics
 // - [ ] Fuzzing
 // - [ ] Speed

 namespace {
    auto print_buffer(std::vector<int32_t> const& buffer, std::size_t data_ptr) {
        printf("buffer: ");
        for (auto const& e : buffer) { printf("%2i|", (int)e); }
        printf("\n        ");
        printf("%*c\n", (int)(data_ptr * 3) + 2, '^');
    }

    auto print_tape(std::string const& tape, std::size_t instr_ptr) {
        printf("tape: ");
        for (auto const& e : tape) { printf("%c", e); }
        printf("\n      ");
        printf("%*c\n", (int)instr_ptr, '^');
    }
 }

 int main(int ac, char** av) {
    if (ac < 3) {
        fprintf(stderr, "usage:\n\t%s buffer_size<int> program<string>\n", av[0]);
        return 1;
    }

    printf("BF interpreter running\n");

    std::string tape { av[2] };
    std::size_t instr_ptr = 0;

    std::vector<int32_t> buffer(std::atoi(av[1]));
    std::size_t data_ptr = 0;

    std::unordered_map<char, std::function<void (void)>> commands = {
        { '>', [&data_ptr]() { data_ptr += 1; } },
        { '<', [&data_ptr]() { data_ptr -= 1; } },
        { '+', [&data_ptr, &buffer]() { buffer[data_ptr] += 1; } },
        { '-', [&data_ptr, &buffer]() { buffer[data_ptr] -= 1; } },
        { '.', [&data_ptr, &buffer]() { printf("%c", buffer[data_ptr]); } },
        { ',', [&data_ptr, &buffer]() { buffer[data_ptr] = std::fgetc(stdin); } },
        { '[', [&data_ptr, &buffer, &instr_ptr, tape]() {
                if (buffer[data_ptr] != 0) { return; }
                instr_ptr -= 1;
                while (tape[instr_ptr] != ']') { instr_ptr += 1; }
            } },
        { ']', [&data_ptr, &buffer, &instr_ptr, tape]() {
                if (buffer[data_ptr] == 0) { return; }
                instr_ptr -= 1;
                std::size_t closed_braces = 0;
                while (tape[instr_ptr] != '[') {
                    instr_ptr -= 1;
                    // skip nested loops on the way back to the original '['
                    if (tape[instr_ptr] == ']') { closed_braces += 1; }
                    if (tape[instr_ptr] == '[' && closed_braces != 0) {
                        closed_braces -= 1; instr_ptr -= 1;
                    }
                }
            } }
    };

    auto end = tape.size();
    while (instr_ptr < end) {
        auto instruction = tape[instr_ptr];
        instr_ptr += 1;
        if (auto search = commands.find(instruction); search != std::end(commands)) {
            search->second();
        }
        // Uncomment to print the tape and buffer's status and step on enter
        // print_buffer(buffer, data_ptr);
        // print_tape(tape, instr_ptr);
        // std::getc(stdin);
    }
    printf("\n");
 }
	#include <cstdio>
	#include <functional>
	#include <unordered_map>
	#include <vector>

	// Notes
	// [some brainfuck fluff by daniel b cristofani](http://www.hevanet.com/cristofd/brainfuck/)
	// [The Epistle to the Implementors](http://www.hevanet.com/cristofd/brainfuck/epistle.html)
	// [The BrainFuck Compiler Collection](https://github.com/Sirflankalot/bfcc)

	// TODO
	// - [ ] Parser
	// - [ ] Tests
	// - [ ] Graphics
	// - [ ] Fuzzing
	// - [ ] Speed

	namespace {
	auto print_buffer(std::vector<int32_t> const& buffer, std::size_t data_ptr) {
	printf("buffer: ");
	for (auto const& e : buffer) { printf("%2i\|", (int)e); }
	printf("\n ");
	printf("%c\n", (int)(data_ptr 3) + 2, '^');
	}

	auto print_tape(std::string const& tape, std::size_t instr_ptr) {
	printf("tape: ");
	for (auto const& e : tape) { printf("%c", e); }
	printf("\n ");
	printf("%*c\n", (int)instr_ptr, '^');
	}
	}

	int main(int ac, char** av) {
	if (ac < 3) {
	fprintf(stderr, "usage:\n\t%s buffer_size<int> program<string>\n", av[0]);
	return 1;
	}

	printf("BF interpreter running\n");

	std::string tape { av[2] };
	std::size_t instr_ptr = 0;

	std::vector<int32_t> buffer(std::atoi(av[1]));
	std::size_t data_ptr = 0;

	std::unordered_map<char, std::function<void (void)>> commands = {
	{ '>', [&data_ptr]() { data_ptr += 1; } },
	{ '<', [&data_ptr]() { data_ptr -= 1; } },
	{ '+', [&data_ptr, &buffer]() { buffer[data_ptr] += 1; } },
	{ '-', [&data_ptr, &buffer]() { buffer[data_ptr] -= 1; } },
	{ '.', [&data_ptr, &buffer]() { printf("%c", buffer[data_ptr]); } },
	{ ',', [&data_ptr, &buffer]() { buffer[data_ptr] = std::fgetc(stdin); } },
	{ '[', [&data_ptr, &buffer, &instr_ptr, tape]() {
	if (buffer[data_ptr] != 0) { return; }
	instr_ptr -= 1;
	while (tape[instr_ptr] != ']') { instr_ptr += 1; }
	} },
	{ ']', [&data_ptr, &buffer, &instr_ptr, tape]() {
	if (buffer[data_ptr] == 0) { return; }
	instr_ptr -= 1;
	std::size_t closed_braces = 0;
	while (tape[instr_ptr] != '[') {
	instr_ptr -= 1;
	// skip nested loops on the way back to the original '['
	if (tape[instr_ptr] == ']') { closed_braces += 1; }
	if (tape[instr_ptr] == '[' && closed_braces != 0) {
	closed_braces -= 1; instr_ptr -= 1;
	}
	}
	} }
	};

	auto end = tape.size();
	while (instr_ptr < end) {
	auto instruction = tape[instr_ptr];
	instr_ptr += 1;
	if (auto search = commands.find(instruction); search != std::end(commands)) {
	search->second();
	}
	// Uncomment to print the tape and buffer's status and step on enter
	// print_buffer(buffer, data_ptr);
	// print_tape(tape, instr_ptr);
	// std::getc(stdin);
	}
	printf("\n");
	}