bonus almost working

.vscode/settings.json

@@ -5,6 +5,7 @@
     "interrupt.h": "c",
     "timer.h": "c",
     "usart.h": "c",
-    "utils.h": "c"
+    "utils.h": "c",
+    "bitmanip.h": "c"
   }
 }

module02/ex04/main.c

@@ -13,9 +13,35 @@
 // TIMER
 #define PERIOD				2000
 #define PRESCALE_VALUE		1024													// can be 1, 8, 64, 256, 1024
+#define STRLEN_LITERAL(str)			(sizeof(str) / sizeof(str[0]) - 1)						// -1 to remove the null terminator, only works with string literals, not with pointers
 
 // END MACROS
 
+// FUNCTION PROTOTYPES
+void uart_init();
+// char uart_rx(void);
+void uart_tx(char c);
+void uart_printstr(const char* str);
+void check_str(char input, volatile char compare_str[], unsigned int length);
+void reset_message();
+void ask_for_username();
+void ask_for_password();
+void on_error();
+void on_success();
+
+// GLOBAL VARIABLES
+typedef enum {
+    USERNAME,
+    PASSWORD
+} State;
+volatile char username[] = "admin";
+volatile char password[] = "password";
+volatile int input_index = 0;
+volatile State state = USERNAME;
+volatile int input_match = FALSE;
+volatile int username_correct = FALSE;
+volatile int password_correct = FALSE;
+
 void uart_init() {
 	UBRR0H = (unsigned char) (BAUD_PRESCALER(USART_BAUDRATE) >> 8);					// 20.11.5 : UBRRnL and UBRRnH – USART Baud Rate Registers
 	UBRR0L = (unsigned char) BAUD_PRESCALER(USART_BAUDRATE);
@@ -35,22 +61,120 @@ void uart_tx(char c) {
 	UDR0 = (unsigned char) c;														// 20.11.1 : Put data into buffer, UDRn – USART I/O Data Register (read and write)
 }
 
+void uart_printstr(const char* str) {
+	while (*str) {
+		uart_tx(*str);
+		str++;
+	}
+}
+
 ISR(USART_RX_vect) {																// Table 12-7 : we select the code for USART Receive
 	// char received_char = uart_rx();
-	char received_char = UDR0;				// Read received character
+	char received_char = UDR0;														// read received character
-	if (received_char == '\b' || received_char == 127) {  // If backspace is received
+	if (received_char == '\b' || received_char == 127) {							// if backspace is received
+		if (input_index <= 0) return;
+		input_index--;
 		uart_tx('\b');  // Move cursor back
 		uart_tx(' ');   // Erase the character on screen
 		uart_tx('\b');  // Move cursor back again
+	} else if (received_char == '\n' || received_char == '\r') {					// if enter is received
+		if (state == USERNAME) {
+			if (input_index == STRLEN_LITERAL(username) && input_match) {
+				username_correct = TRUE;
 			} else {
-		uart_tx(SWITCH_CASE(received_char)); // Toggle case and send back
+				username_correct = FALSE;
+				uart_printstr("(error1)");
 			}
+			input_match = FALSE;
+			state = PASSWORD;
+			input_index = 0;
+			uart_tx('\r');															// Move cursor to next line
+			uart_tx('\n');
+			ask_for_password();
+		} else if (state == PASSWORD) {
+			if (!username_correct) {
+				uart_printstr("(error2)");
+				return reset_message();
+			}
+			if (input_index != STRLEN_LITERAL(password)) {
+				uart_printstr("(error3)");
+				return reset_message();
+			}
+			if (!input_match) {
+				uart_printstr("(error4)");
+				return reset_message();
+			}
+			uart_tx('\r');															// Move cursor to next line
+			uart_tx('\n');
+			on_success();
+		}
+	} else {
+		if (state == USERNAME) {
+			check_str(received_char, username, STRLEN_LITERAL(username));
+			uart_tx(received_char);
+		}
+		else if (state == PASSWORD) {
+			check_str(received_char, password, STRLEN_LITERAL(password));
+			uart_tx('*');
+		}
+		input_index++;
+	}
+}
+
+void check_str(char input, volatile char compare_str[], unsigned int length) {
+	if (input_index >= length) {														// index has not already been incremented, so we need to compare greater or equal
+		uart_printstr("(error5)");
+		input_match = FALSE;
+		return;
+	}
+	if (input != compare_str[input_index]) {
+		uart_printstr("(error6)");
+		input_match = FALSE;
+		return;
+	}
+	// if we reach this point, the input character matches the compare_str character
+	if (input_index == 0) {
+		input_match = TRUE;
+		return;
+	}
+	// if we reach this point, the input character is not the first character of the compare_str
+	if (input_match == FALSE) {
+		// if any previous character did not match, we don't need to check the next character
+		uart_printstr("(error7)");
+		return;
+	}
+	input_match = TRUE;
+}
+
+void reset_message() {
+	input_index = 0;
+	input_match = FALSE;
+	username_correct = FALSE;
+	password_correct = FALSE;
+	state = USERNAME;
+	uart_tx('\r');																// Move cursor to next line
+	uart_tx('\n');
+	on_error();
+	ask_for_username();
+}
+void ask_for_username() {
+	uart_printstr("Enter your login: \r\n    username: ");
+}
+void ask_for_password() {
+	uart_printstr("    password: ");
+}
+void on_error() {
+	uart_printstr("Bad combinaison username/password\r\n\r\n");
+}
+void on_success() {
+	uart_printstr("Hello spectre!\r\nShall we play a game?\r\n");
 }
 
 // ask for username and password
 // `screen /dev/ttyUSB0 115200`
 int main() {
 	uart_init();
+	ask_for_username();
 
 	SREG |= ENABLE_GLOBAL_INTERRUPT;												// 7.3.1 : Status Register, bit 7 : I – Global Interrupt Enable
 

module02/ex04/utils.h

@@ -16,4 +16,8 @@
 // text
 #define SWITCH_CASE(ch) (((ch) >= 'A' && (ch) <= 'Z') || ((ch) >= 'a' && (ch) <= 'z') ? ((ch) ^ (1 << 5)) : (ch))
 
+// boolean
+#define TRUE						1
+#define FALSE						0
+
 #endif // UTILS_H