88 lines
2.2 KiB
C++
88 lines
2.2 KiB
C++
#include <cstdint>
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#include <string>
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#include <array>
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#include <stack>
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#include <fstream>
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#include <iostream>
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#include <filesystem>
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std::string get_file_contents(std::ifstream& file_stream) {
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std::string file_string;
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file_stream.seekg(0, std::ios::end);
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file_string.resize(file_stream.tellg());
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file_stream.seekg(0, std::ios::beg);
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file_stream.read(&file_string[0], file_string.size());
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return file_string;
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}
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std::string get_brainfuck_code(const std::string& file) {
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std::string code;
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for (auto c : file) {
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switch (c) {
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case '>': case '<':
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case '+': case '-':
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case '.': case ',':
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case '[': case ']':
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code.push_back(c);
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}
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}
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return code;
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}
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template<typename value_type, std::size_t size>
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struct bf_context_t {
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std::array<value_type, size> cells;
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std::stack<std::size_t> scope;
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std::uintptr_t ptr;
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};
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int main(int argc, char* argv[]) {
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if (argc < 2) {
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std::cout << "Usage: " << argv[0] << std::endl;
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return 1;
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}
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const std::string file_path = argv[1];
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if (!std::filesystem::exists(file_path)) {
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std::cout << "Could not find file." << std::endl;
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return 1;
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}
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std::ifstream file_stream(file_path);
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if (!file_stream) {
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std::cout << "Could not open file." << std::endl;
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return 1;
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}
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const std::string file_contents = get_file_contents(file_stream);
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const std::string bf_code = get_brainfuck_code(file_contents);
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// by default, std::cin skips whitespace
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std::cin >> std::noskipws;
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auto ctx = bf_context_t<std::uint8_t, 30'000>{};
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for (auto ip = 0; ip < bf_code.length(); ++ip) {
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switch (bf_code[ip]) {
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case '>': ++ctx.ptr; break;
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case '<': --ctx.ptr; break;
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case '+': ++ctx.cells[ctx.ptr]; break;
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case '-': --ctx.cells[ctx.ptr]; break;
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case '.': std::cout << (char)ctx.cells[ctx.ptr]; break;
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case ',': std::cin >> ctx.cells[ctx.ptr]; break;
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case '[': ctx.scope.push(ip); break;
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case ']': if (ctx.cells[ctx.ptr]) ip = ctx.scope.top() - 1; ctx.scope.pop(); break;
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}
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}
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}
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