From 98215c5ad6f9ad618aab5126b78ada1cbbd82e86 Mon Sep 17 00:00:00 2001
From: Christoph Urlacher <christoph.urlacher@protonmail.com>
Date: Thu, 18 Jan 2024 21:12:40 +0100
Subject: [PATCH] Implemented .bfuck file reading

---
 include/lex.hpp | 16 ++++++++++++++++
 src/lex.cpp     | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 include/lex.hpp
 create mode 100644 src/lex.cpp

diff --git a/include/lex.hpp b/include/lex.hpp
new file mode 100644
index 0000000..f9a6556
--- /dev/null
+++ b/include/lex.hpp
@@ -0,0 +1,16 @@
+#ifndef __LEX_H_
+#define __LEX_H_
+
+#include <string>
+
+/**
+ * @brief Lex a brainfuck file to a string from disk. Each element is a token.
+ * @param path The path to the file to be lexed
+ * @param tokens The string where the tokens will be written to
+ * @return True if the file was lexed successfully
+ */
+bool lex_brainfuck_file(const std::string &path, std::string &tokens);
+
+bool token_string_valid(std::string_view tokens);
+
+#endif
\ No newline at end of file
diff --git a/src/lex.cpp b/src/lex.cpp
new file mode 100644
index 0000000..adaf023
--- /dev/null
+++ b/src/lex.cpp
@@ -0,0 +1,47 @@
+#include "lex.hpp"
+
+#include <iostream>
+#include <fstream>
+#include <algorithm>
+
+bool lex_brainfuck_file(const std::string &path, std::string &tokens) {
+    if (!tokens.empty()) {
+        std::cout << "Result string \"tokens\" has to be empty!" << std::endl;
+        return false;
+    }
+
+    std::ifstream input_stream;
+    input_stream.open(path, std::ios::in);
+    if (!input_stream.is_open()) {
+        std::cout << "Failed to open file \"" << path << "\"" << std::endl;
+        return false;
+    }
+
+    std::string line;
+    while (std::getline(input_stream, line)) {
+        tokens += line;
+    }
+
+    if (!input_stream.eof() && input_stream.fail()) {
+        std::cout << "Error reading from file \"" << path << "\"" << std::endl;
+        input_stream.close();
+        return false;
+    }
+    input_stream.close();
+
+    if (!token_string_valid(tokens)) {
+        std::cout << "Program is invalid!" << std::endl;
+        return false;
+    }
+
+    std::cout << "Lexed BrainFuck program:\n" << tokens << std::endl;
+    return true;
+}
+
+bool token_string_valid(const std::string_view tokens) {
+    std::string valid_tokens = "><+-.,[]";
+
+    return std::ranges::all_of(tokens.begin(), tokens.end(), [&valid_tokens](const char c){
+        return valid_tokens.find(c) != std::string::npos;
+    });
+}
\ No newline at end of file