Created
May 8, 2022 04:05
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A brainfuck interpreter I wrote in C++ for fun.
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| #include <fstream> | |
| #include <iostream> | |
| std::string minimize(std::string s) { | |
| std::string res; | |
| for (char c : s) | |
| if ((std::string("[],.<>+-")).find(c) != std::string::npos) | |
| res += c; | |
| return res; | |
| } | |
| int main(int argc, char* argv[]) { | |
| if (argc != 2) { | |
| std::cout << "Usage: " << argv[0] << " <file>\n"; | |
| return 1; | |
| } | |
| std::ifstream file(argv[1]); | |
| if (!file.is_open()) { | |
| std::cout << "Could not open file \"" << argv[1] << "\"\n"; | |
| return 1; | |
| } | |
| char c; | |
| std::string contents; | |
| while (file.get(c)) contents += c; | |
| std::string compact = minimize(contents); | |
| const char* code = compact.c_str(); | |
| const char* ctr = code; | |
| char mem[30000]; | |
| std::fill(mem, mem + 30000, 0); | |
| char* ptr = mem; | |
| int pos = 0; | |
| int i; | |
| while (*ctr) { | |
| switch (*ctr) { | |
| case '>': | |
| ptr++; | |
| if (++pos == 30000) { | |
| std::cout << "Memory overflow\n"; | |
| return 1; | |
| } | |
| break; | |
| case '<': | |
| ptr--; | |
| if (--pos == -1) { | |
| std::cout << "Memory underflow\n"; | |
| return 1; | |
| } | |
| break; | |
| case '+': | |
| if (++*ptr > 255) *ptr = 0; | |
| break; | |
| case '-': | |
| if (--*ptr < 0) *ptr = 255; | |
| break; | |
| case '.': | |
| std::cout << *ptr; | |
| break; | |
| case ',': | |
| std::cin >> *ptr; | |
| break; | |
| case '[': | |
| i = 1; | |
| if (*ptr == 0) { | |
| do { | |
| ctr++; | |
| if (*ctr == '[') | |
| i++; | |
| else if (*ctr == ']') | |
| i--; | |
| } while (i != 0); | |
| } | |
| break; | |
| case ']': | |
| i = 0; | |
| do { | |
| if (*ctr == '[') | |
| i++; | |
| else if (*ctr == ']') | |
| i--; | |
| ctr--; | |
| } while (i != 0); | |
| } | |
| ctr++; | |
| } | |
| } |
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