Chaged FileSettings delays type to std::chrono:milliseconds

Changed file format for a FileTape - added and example in the class comment
Removed prev_line_pos and at_first_line fields from FieldTape
Changed Tape data type from int32_t to uint32_t
Cleand up includes
Implemented FileTape methods
Unit tests are in working state

include/tapelib/filetape.h

@@ -2,10 +2,10 @@
 #define FILE_TAPE_H
 
 #include "tape.h"
-#include <cstddef>
-#include <cstdint>
+#include <chrono>
 #include <fstream>
-#include <string>
+
+using std::chrono::milliseconds;
 
 namespace tape {
 
@@ -14,35 +14,46 @@ namespace tape {
  * such as read dealy, write delay etc.
  */
 struct FileTapeSettings {
-    unsigned int read_delay_ms;
-    unsigned int write_delay_ms;
-    unsigned int seek_forward_delay_ms;
-    unsigned int seek_backwards_delay_ms;
+    milliseconds read_delay;
+    milliseconds write_delay;
+    milliseconds seek_forward_delay;
+    milliseconds seek_backwards_delay;
 };
 
-const static struct FileTapeSettings DEFAULT_FT_SETTINGS =
-    FileTapeSettings{.read_delay_ms = 0,
-                     .write_delay_ms = 0,
-                     .seek_forward_delay_ms = 0,
-                     .seek_backwards_delay_ms = 0};
+const static struct FileTapeSettings FT_DEFAULT_SETTINGS =
+    FileTapeSettings{.read_delay = milliseconds(0),
+                     .write_delay = milliseconds(0),
+                     .seek_forward_delay = milliseconds(0),
+                     .seek_backwards_delay = milliseconds(0)};
 
 const static char FT_DELIMETER = '\n';
 
+// uint32_t digits max count is 10
+const static int FT_CELL_SIZE = 10;
+const static int FT_SEEK_OFFSET = FT_CELL_SIZE + 1;
+
 /**
  * Mock tape implementation that uses text files as data source.
  *
  * Simulates tape operations by artificially pausing the execution of some
  * methods using time intervals, specified in command line arguments or a
- * configuration file. Each cell is represented as a plain text 32-bit int
- * separated by FT_DELIMETER. End of the file tape is indicated either by EOF
- * or some arbitrary data that cannot be parsed to int32_t
+ * configuration file. Each cell is represented as a plain text 32-bit unsigned
+ * int, padded to FT_CELL_SIZE with leading zeroes, separated by FT_DELIMETER.
+ * Each cell MUST be FT_CELL_SIZE long to correctly implement write operation
+ * without re-writing the entire file. FT_DELIMETER
+ *
+ * Example of a valid file for a FileTape
+ * - example.txt
+ *   000000001
+ *   000000034
+ *   000001234
+ *   123456789
+ *   000000000
  */
 class FileTape : public Tape {
   private:
     std::fstream file;
     FileTapeSettings settings;
-    size_t prev_line_pos = 0;
-    bool at_first_line = false;
 
   public:
     /**
@@ -54,7 +65,7 @@ class FileTape : public Tape {
      * @param settings FileTape settings
      */
     explicit FileTape(const std::string &file_name,
-                      FileTapeSettings settings = DEFAULT_FT_SETTINGS);
+                      FileTapeSettings settings = FT_DEFAULT_SETTINGS);
 
     /**
      * Initializes a new instance of FileTape that will create and open a file
@@ -66,7 +77,7 @@ class FileTape : public Tape {
      * @param settings FileTape settings
      */
     explicit FileTape(size_t size, const std::string &file_name,
-                      FileTapeSettings settings = DEFAULT_FT_SETTINGS);
+                      FileTapeSettings settings = FT_DEFAULT_SETTINGS);
 
     /**
      * Initializes a new instance of FileTape that will create and open a
@@ -76,7 +87,7 @@ class FileTape : public Tape {
      * @param settings FileTape settings
      */
     explicit FileTape(size_t size,
-                      FileTapeSettings settings = DEFAULT_FT_SETTINGS);
+                      FileTapeSettings settings = FT_DEFAULT_SETTINGS);
 
     /**
      * Advances the underlying fstream to a new line.
@@ -97,14 +108,14 @@ class FileTape : public Tape {
      *
      * @return number from the line, or 0 if data can not be parsed.
      */
-    int32_t read() override;
+    uint32_t read() override;
 
     /**
      * Writes data to the current line.
      *
      * @param data Number, that should be written to the current line.
      */
-    void write(int32_t data) override;
+    void write(uint32_t data) override;
 };
 
 } // namespace tape

include/tapelib/tape.h

@@ -9,7 +9,7 @@ namespace tape {
  * Abstract class representing a magnetic tape.
  *
  * Tape is a storage medium consisting of N cells, where each cell contains a
- * 32-bit signed integer. Data can be read or written into one cell at a time.
+ * 32-bit unsigned integer. Data can be read or written into one cell at a time.
  * Tape can be moved one cell forward or backwards in order to change the
  * targeted cell. Tape performs every operation sequentially. The amount of data
  * stored on a single tape could exceed the amount of available RAM. Moving tape
@@ -45,14 +45,14 @@ class Tape {
      *
      * @return number, that is stored on the current cell.
      */
-    virtual int32_t read() = 0;
+    virtual uint32_t read() = 0;
 
     /**
      * Writes data to the current cell.
      *
      * @param data Number, that should be written to the current cell.
      */
-    virtual void write(int32_t data) = 0;
+    virtual void write(uint32_t data) = 0;
 };
 
 } // namespace tape

src/filetape.cpp

@@ -1,41 +1,81 @@
 #include "filetape.h"
-#include <array>
-#include <cstdint>
-#include <cstdio>
-#include <fstream>
-#include <string>
+#include <thread>
 
+using std::fstream;
 using tape::FileTape;
 
 FileTape::FileTape(const std::string &file_name, FileTapeSettings settings)
     : settings(settings) {
-    this->file = std::fstream(file_name);
+    this->file = fstream(file_name);
+}
+
+void fill_file_with_empty_cells(size_t size, fstream &file) {
+    file << std::setfill('0') << std::setw(tape::FT_CELL_SIZE + 1);
+    for (int i = 0; i < size; i++) {
+        file << tape::FT_DELIMETER << std::setfill('0')
+             << std::setw(tape::FT_CELL_SIZE + 1);
+    }
+    file.seekg(0, fstream::beg);
 }
 
 FileTape::FileTape(size_t size, const std::string &file_name,
                    FileTapeSettings settings)
     : FileTape(file_name, settings) {
-    this->file << "0";
-    for (int i = 0; i < size; i++) {
-        this->file << FT_DELIMETER << "0";
-    }
+    this->file =
+        fstream(file_name, fstream::in | fstream::out | fstream::trunc);
+    fill_file_with_empty_cells(size, file);
 }
 
 FileTape::FileTape(size_t size, FileTapeSettings settings)
     : settings(settings) {
     std::array<char, L_tmpnam> file_name{};
+    // tmpnam is unsafe, but its cross-platform
+    // create a platform dependant tmp file handler later
     std::tmpnam(file_name.data());
-    this->file = std::fstream(file_name.data());
-    this->file << "0";
-    for (int i = 0; i < size; i++) {
-        this->file << FT_DELIMETER << "0";
-    }
+    this->file =
+        fstream(file_name.data(), fstream::in | fstream::out | fstream::trunc);
+    fill_file_with_empty_cells(size, file);
 }
 
-bool FileTape::seek_forward() { return true; }
+bool FileTape::seek_backwards() {
+    std::this_thread::sleep_for(this->settings.seek_backwards_delay);
+    if (this->file.tellg() == 0) {
+        return false;
+    }
+    this->file.seekg(-FT_SEEK_OFFSET, fstream::cur);
+    return true;
+}
 
-bool FileTape::seek_backwards() { return true; }
+bool FileTape::seek_forward() {
+    std::this_thread::sleep_for(this->settings.seek_forward_delay);
+    this->file.seekg(FT_SEEK_OFFSET, fstream::cur);
+    this->file.peek();
+    if (this->file.eof()) {
+        this->file.clear();
+        this->file.seekg(-FT_SEEK_OFFSET, fstream::end);
+        return false;
+    }
+    return true;
+}
 
-int32_t FileTape::read() { return 0; }
+uint32_t FileTape::read() {
+    std::this_thread::sleep_for(this->settings.read_delay);
+    uint32_t data = 0;
+    this->file >> data;
+    if (this->file.eof()) {
+        this->file.clear();
+        this->file.seekg(-FT_SEEK_OFFSET + 2, fstream::end);
+        return data;
+    }
+    this->file.seekg(-FT_SEEK_OFFSET + 1, fstream::cur);
+    return data;
+}
 
-void FileTape::write(int32_t data) {}
+void FileTape::write(uint32_t data) {
+    std::this_thread::sleep_for(this->settings.write_delay);
+    std::stringstream cell;
+    cell << std::setfill('0') << std::setw(FT_CELL_SIZE)
+         << std::to_string(data);
+    this->file.write(cell.str().data(), FT_CELL_SIZE);
+    this->file.seekg(-FT_SEEK_OFFSET + 1, fstream::cur);
+}

src/tape_config.cpp

@@ -1,6 +1,4 @@
 #include "tape_config.h"
-#include "filetape.h"
-#include <string>
 
 struct CommandLineArgs {
     std::string config_file_path;

tests/CMakeLists.txt

@@ -5,3 +5,4 @@ target_link_libraries(filetape_tests PRIVATE tapelib)
 target_link_libraries(filetape_tests PRIVATE Catch2::Catch2WithMain)
 
 add_test(filetape_tests filetape_tests)
+add_compile_definitions(FILETAPE_TEST_FILE=\"${PROJECT_SOURCE_DIR}/tests/assets/filetape_test_data.txt\")

tests/assets/filetape_test_data.txt

@@ -1,5 +1,5 @@
-1
-2
-3
-4
-5
+0000000001
+0000000002
+0000000003
+0000000004
+0000000005

tests/filetape_tests.cpp

@@ -1,10 +1,9 @@
 #include "filetape.h"
 #include <catch2/catch_test_macros.hpp>
-#include <cstdio>
 
 // NOLINTBEGIN(readability-function-cognitive-complexity)
 TEST_CASE("Reading data from a FileTape", "[filetape]") {
-    tape::FileTape tape("assets/filetape_test_data.txt");
+    tape::FileTape tape(FILETAPE_TEST_FILE);
 
     SECTION("Read all data sequentially") {
         REQUIRE(tape.read() == 1);
@@ -35,7 +34,7 @@ TEST_CASE("Reading data from a FileTape", "[filetape]") {
 }
 
 TEST_CASE("Seeking forward and backwards", "[filetape]") {
-    tape::FileTape tape("assets/filetape_test_data.txt");
+    tape::FileTape tape(FILETAPE_TEST_FILE);
 
     SECTION("Rewinding at the beginning of a file tape") {
         REQUIRE(tape.seek_backwards() == false);
@@ -64,11 +63,20 @@ TEST_CASE("Seeking forward and backwards", "[filetape]") {
 }
 
 TEST_CASE("Writing to a file tape", "[filetape]") {
-    // init a temp file to modify
-    // std::string tmp_file_name = "/tmp/"
-    // std::unique_ptr<std::FILE> tmp_file(std::tmpfile());
-    // std::fstream tmp(tmp_file);
-    // std::fstream tmp(tmp_file);
-    // tape::FileTape tape("assets/filetape_test_data.txt");
+    tape::FileTape tape(3);
+
+    tape.write(0);
+    REQUIRE(tape.read() == 0);
+    tape.seek_forward();
+    tape.write(1);
+    REQUIRE(tape.read() == 1);
+    tape.seek_forward();
+    tape.write(2);
+    REQUIRE(tape.read() == 2);
+    tape.write(3);
+    REQUIRE(tape.read() == 3);
+    tape.seek_backwards();
+    tape.write(4);
+    REQUIRE(tape.read() == 4);
 }
 // NOLINTEND(readability-function-cognitive-complexity)