file rewad and write

CMakeLists.txt

@@ -3,4 +3,4 @@ project(Steganography)
 
 set(CMAKE_CXX_STANDARD 17)
 
-add_executable(Steganography main.cpp src/utils/argparse.h src/steganography/ISteganography.h src/steganography/JpgStegano.h src/steganography/JpgStegano.cpp)
+add_executable(Steganography main.cpp src/utils/argparse.h src/steganography/ISteganography.h src/steganography/JpgStegano.h src/steganography/JpgStegano.cpp src/utils/fileutil.h)

src/steganography/JpgStegano.cpp

@@ -2,12 +2,16 @@
 // Created by kyohei.okawa on 2021/07/05.
 //
 
+#include <fstream>
+#include <iostream>
 #include <string>
 #include <vector>
 #include "./JpgStegano.h"
+#include "../utils/fileutil.h"
 
 void JpgStegano::Insert(std::string imagePath, std::string str) {
-
+    std::vector<std::byte> data = FileUtil::Read(imagePath);
+    FileUtil::Write(data, imagePath);
 }
 
 std::vector<std::byte> JpgStegano::Load(std::string imagePath) {

src/utils/fileutil.h

@@ -0,0 +1,55 @@
+//
+// Created by kyohei.okawa on 2021/07/05.
+//
+
+#ifndef STEGANOGRAPHY_FILEUTIL_H
+#define STEGANOGRAPHY_FILEUTIL_H
+
+#include <stdio.h>
+#include <fstream>
+#include <iostream>
+
+namespace FileUtil {
+
+    std::vector<std::byte> Read(std::string path) {
+        std::ifstream ifs(path, std::ios::binary);
+        if (ifs.fail()) {
+            std::cerr << "Failed to open file" << std::endl;
+            return std::vector<std::byte>();
+        }
+
+
+        ifs.seekg(0, std::ios::end);
+        long long int size = ifs.tellg();
+        ifs.seekg(0);
+
+        char *data = new char[size];
+        ifs.read(data, size);
+        std::vector<std::byte> ret;
+        for (int i = 0; i < size; i++) {
+            ret.push_back((std::byte) data[i]);
+        }
+        delete[] data;
+
+        ifs.close();
+        return ret;
+    }
+
+    void Write(std::vector<std::byte> data, std::string path) {
+        std::ofstream fout(path, std::ios::out | std::ios::binary | std::ios::trunc);
+
+        if (fout.fail()) {
+            std::cerr << "Failed to open file" << std::endl;
+            return;
+        }
+
+        for(int i = 0; i < data.size(); i++) {
+            fout.write((char *)&data[i], sizeof(std::byte));
+        }
+
+        fout.close();
+    }
+
+}
+
+#endif //STEGANOGRAPHY_FILEUTIL_H