lib/file: Implement cutString function

src/lib/file.cpp

@@ -65,6 +65,8 @@ void File::open(){
 
 void File::close(){
     this->fileStream.close();
+    std::filesystem::path filePath = this->path;
+    this->size = ErrorOr<uint64_t>(std::filesystem::file_size(filePath));
     this->isOpen = false;
 }
 
@@ -255,7 +257,7 @@ ErrorOr<uint8_t> File::cutByte(){
         std::filesystem::resize_file(this->path, readData.size());
         this->fileStream.seekg(0);
         this->write(readData);
-        this->cursorPosition++;
+        //this->cursorPosition++;
         delete[] buffer;
     }catch(std::exception& e){
         failure = true;
@@ -280,7 +282,7 @@ ErrorOr<std::vector<uint8_t>> File::cut(uint64_t length){
         std::filesystem::resize_file(this->path, readData.size());
         this->fileStream.seekg(0);
         this->write(readData);
-        this->cursorPosition += length;
+        //this->cursorPosition += length;
         delete[] buffer;
     }catch(std::exception& e){
         failure = true;
@@ -289,6 +291,30 @@ ErrorOr<std::vector<uint8_t>> File::cut(uint64_t length){
     return failure ? ErrorOr<std::vector<uint8_t>>(true, ErrorCodes::UNKNOWN) :ErrorOr<std::vector<uint8_t>>(bytes);
 }
 
+ErrorOr<tiny_utf8::string> File::cutString(uint64_t length){
+    bool failure = false;
+    tiny_utf8::string cutString;
+    try{
+        uint8_t* buffer = new uint8_t[this->size.value];
+        tiny_utf8::string readData;
+
+        this->fileStream.read(reinterpret_cast<char*>(buffer), this->size.value);
+        readData = tiny_utf8::string((char *) buffer, 0, this->size.value);
+        
+        cutString = readData.substr(this->cursorPosition, length);
+
+        std::filesystem::resize_file(this->path, readData.size()-cutString.size());
+        this->fileStream.seekg(0);
+        this->writeString(readData.substr(this->cursorPosition+length));
+        //this->cursorPosition += length;
+        delete[] buffer;
+    }catch(std::exception& e){
+        failure = true;
+    }
+
+    return failure ? ErrorOr<tiny_utf8::string>(true, ErrorCodes::UNKNOWN) : ErrorOr<tiny_utf8::string>(cutString);
+}
+
 ErrorOr<File*> File::open(std::string path, char mode, uint64_t startPosition){
     if (!std::filesystem::exists(path) && (mode == 'r' || mode == 'm')) {
         return ErrorOr<File*>(true, ErrorCodes::FILE_NOT_FOUND, nullptr);

src/test/file.cpp

@@ -177,6 +177,7 @@ int main(){
     tiny_utf8::string cutByteString = readFile->readString(readFile->size.value).value;
     readFile->close();    
 
+    ASSERT(modifyFile->cursorPosition == modifyFile->size.value);
     ASSERT(cutByte.value == '.');
     ASSERT(cutByteString == "Hallo, Hi THE CAKE IS A LIE, Ich bin Shwoomple");
     std::cout << "Passed cut byte test." << std::endl;
@@ -191,7 +192,24 @@ int main(){
     tiny_utf8::string cutBytesString = readFile->readString(readFile->size.value).value;
     readFile->close();
 
+
+    ASSERT(modifyFile->cursorPosition == 9);
     ASSERT(cutBytes.value == std::vector<uint8_t>({' ', 'T', 'H', 'E', ' ', 'C', 'A', 'K', 'E', ' ', 'I', 'S', ' ','A', ' ', 'L', 'I', 'E'}))
     ASSERT(cutBytesString == "Hallo, Hi, Ich bin Shwoomple");
     std::cout << "Passed cut test." << std::endl;
+
+    modifyFile->open();
+    modifyFile->cursorPosition = 0;
+    ErrorOr<tiny_utf8::string> cutString = modifyFile->cutString(7);
+    modifyFile->close();
+
+    readFile->open();
+    readFile->cursorPosition = 0;
+    tiny_utf8::string cutReadString = readFile->readString(readFile->size.value).value;
+    readFile->close();
+
+    ASSERT(modifyFile->cursorPosition == 0);
+    ASSERT(cutString.value == "Hallo, ");
+    ASSERT(cutReadString == "Hi, Ich bin Shwoomple");
+    std::cout << "Passed cutString test." << std::endl;
 }