Morse Encoder & Displayer

#include <LiquidCrystal.h>

LiquidCrystal lcd(2, 3, 4, 5, 6, 7);

#define BUZZER 11

#define SMALLER_DELAY 128

PROGMEM const uint8_t morse_code_a_z[26] = {
  0b01100000, // A .-
  0b10010101, // B -...
  0b10011001, // C -.-.
  0b10010100, // D -..
  0b01000000, // E .
  0b01011001, // F ..-.
  0b10100100, // G --.
  0b01010101, // H ....
  0b01010000, // I ..
  0b01101010, // J .---
  0b10011000, // K -.-
  0b01100101, // L .-..
  0b10100000, // M --
  0b10010000, // N -.
  0b10101000, // O ---
  0b01101001, // P .--.
  0b10100110, // Q --.-
  0b01100100, // R .-.
  0b01010100, // S ...
  0b10000000, // T -
  0b01011000, // U ..-
  0b01010110, // V ...-
  0b01101000, // W .--
  0b10010110, // X -..-
  0b10011010, // Y -.--
  0b10100101, // Z --..
};

void send_bit(const bool& dash) {
  lcd.print(dash ? '-' : '.');
  analogWrite(BUZZER, 63);
  delay((dash ? 3 : 1) * SMALLER_DELAY);
  digitalWrite(BUZZER, LOW);
  delay(1 * SMALLER_DELAY);
}

uint8_t hpos = 0;

void send_char(const char& c) {
  // Send the character to the LCD
  lcd.setCursor(hpos++, 0);
  lcd.print(c);
  
  // Position the cursor to the next line to start the .- sequence
  lcd.setCursor(0, 1);
  lcd.print("     ");
  lcd.setCursor(0, 1);
}

void print_number(const char& number) {
  if (!isDigit(number)) return;

  send_char(number);
  
  uint8_t num = number - '0';
  for (uint8_t i = 0 ; i < 5 ; i++) {
    if (num == i) num += 10;
    
    if (num < 6 + i) send_bit(false);
    else send_bit(true);
  }
}

void print_character(char character) {
  if (!isAlpha(character)) return;

  if (isLowerCase(character)) character += 'A' - 'a';

  send_char(character);

  uint8_t code = morse_code_a_z[character - 'A'];
  while (code != 0) {
    switch (code >> 6) {
      case 0:
      break;
      case 1:
      send_bit(false);
      break;
      case 2:
      send_bit(true);
      break;
      case 3:
      Serial.print("Error while printing character: ");
      Serial.println(character);
      Serial.print("Got 3 in the 2 leftmost bits of code ");
      Serial.println(code, BIN);
      break;
      default:
      Serial.print("Error while printing character: ");
      Serial.println(character);
      Serial.print("Got ? in the 2 leftmost bits of code ");
      Serial.println(code, BIN);
    }
    code <<= 2;
  }
}

void print_whitespace() {
  send_char(' ');
  delay(3 * SMALLER_DELAY);
}

void print_char(const char& character) {
  if (isWhitespace(character)) print_whitespace();
  else if (isAlpha(character)) print_character(character);
  else if (isDigit(character)) print_number(character);
  else if (isPunct(character)) { send_char(character); delay(1 * SMALLER_DELAY); }
  else if (character == '\0') {}
  else if (character == '\1') { /* This happens at the end of every string, don't know why */ }
  else {
    Serial.print("Error: unknown character ");
    Serial.print(character);
    Serial.print(" (0b");
    Serial.print((uint8_t)character, BIN);
    Serial.println(")");
    send_char('?');
    analogWrite(BUZZER, 63);
    delay(4 * SMALLER_DELAY);
    digitalWrite(BUZZER, LOW);
    delay(1 * SMALLER_DELAY);
  }
  
  delay(2 * SMALLER_DELAY);
}

void print_string(const char* characters, int len = 15) {
  for (uint8_t pos = 0 ; pos <= len ; pos++) {
    print_char(characters[pos]);
  }
}

void reset_LCD() {
  hpos = 0;

  lcd.clear();
  lcd.noCursor();
  lcd.setCursor(0, 0);
}

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  
  lcd.begin(16, 2);
  reset_LCD();

  pinMode(BUZZER, OUTPUT);
}

char* readStr() {
  uint8_t idx = 0;
  char* str = (char*)malloc(128 * sizeof(char));
  
  while (Serial.available() && idx < 128) {
    str[idx] = Serial.read();
    idx++;
    delay(2);
  }
  for ( ; idx < 128 ; idx++) {
    str[idx] = '\0';
  }

  return str;
}

void serialEvent() {
  while (Serial.available()) {
    char* string;
    Serial.setTimeout(-1);
    string = readStr();
    Serial.print("Received: ");
    Serial.println(string);
    
    char substr[16];
    for (uint8_t c = 0 ; c < 128 && string[c] != '\0' && string[c] != '\r' && string[c] != '\n' ; c += 16) {
      for (uint8_t offset = 0 ; offset < 15 ; offset++) {
        if (string[c + offset] != '\0' && string[c + offset] != '\r' && string[c + offset] != '\n') {
          substr[offset] = string[c + offset];
        } else {
          substr[offset] = '\0';
        }
      }

      reset_LCD();
      print_string(substr);
    }

    free((void*)string);
  }
  lcd.setCursor(0, 1);
  lcd.print("     ");
  lcd.setCursor(0, 0);
}

void loop() {
}