implemented rfile reading

simulator_SIC_XE/include/file_reader.h

@@ -0,0 +1,19 @@
+#pragma once
+#include "reader.h"
+#include <string>
+#include <fstream>
+
+class FileReader : public Reader {
+public:
+    explicit FileReader(const std::string &path, std::ios::openmode m = std::ios::binary);
+    ~FileReader() override;
+
+    int readByte() override;
+    bool readBytes(uint8_t* buf, size_t len) override;
+    std::string readString(size_t len) override;
+
+    bool good() const;
+
+private:
+    std::ifstream in;
+};

simulator_SIC_XE/include/reader.h

@@ -0,0 +1,15 @@
+#pragma once
+#include <string>
+#include <cstdint>
+
+// Abstract Reader class: read bytes/strings from a source (file, string, etc.)
+class Reader {
+public:
+    virtual ~Reader() = default;
+    // return 0..255 on success, -1 on EOF/error
+    virtual int readByte() = 0;
+    // read exactly len bytes into buf; return true on success
+    virtual bool readBytes(uint8_t* buf, size_t len) = 0;
+    // read up to len bytes into a std::string; may return shorter string on EOF
+    virtual std::string readString(size_t len) = 0;
+};

simulator_SIC_XE/include/string_reader.h

@@ -0,0 +1,17 @@
+#pragma once
+#include "reader.h"
+#include <string>
+#include <sstream>
+
+class StringReader : public Reader {
+public:
+    explicit StringReader(const std::string &s);
+    ~StringReader() override;
+
+    int readByte() override;
+    bool readBytes(uint8_t* buf, size_t len) override;
+    std::string readString(size_t len) override;
+
+private:
+    std::istringstream in;
+};