raspikeyer/src/morse.cpp

#include <algorithm>
#include <map>
#include <regex>

#include "morse.h"

static std::map<char, std::string> morseCode = {
    {'A', ".-"},      {'B', "-..."},    {'C', "-.-."},   {'D', "-.."},    {'E', "."},      {'F', "..-."},
    {'G', "--."},     {'H', "...."},    {'I', ".."},     {'J', ".---"},   {'K', "-.-"},    {'L', ".-.."},
    {'M', "--"},      {'N', "-."},      {'O', "---"},    {'P', ".--."},   {'Q', "--.-"},   {'R', ".-."},
    {'S', "..."},     {'T', "-"},       {'U', "..-"},    {'V', "...-"},   {'W', ".--"},    {'X', "-..-"},
    {'Y', "-.--"},    {'Z', "--.."},    {'1', ".----"},  {'2', "..---"},  {'3', "...--"},  {'4', "....-"},
    {'5', "....."},   {'6', "-...."},   {'7', "--..."},  {'8', "---.."},  {'9', "----."},  {'0', "-----"},
    {',', "--..--"},  {'.', ".-.-.-"},  {'?', "..--.."}, {'/', "-..-."},  {'-', "-....-"}, {':', "---..."},
    {'&', ".-..."},   {'\'', ".----."}, {'@', ".--.-."}, {')', "-.--.-"}, {'(', "-.--."},  {'\"', ".-..-."},
    {'=', "-...-"},   // '=' == <BT>
    {'b', "-...-.-"}, // '=' == <BK>
    {'k', "-.--."},   // k == <KN>
    {'s', "...-.-"},  // s == <SK>
    {'+', ".-.-."},   // + == <AR>
    {'a', "-.-.-"},   // a == <KA>
};

void refurbishMessage(std::string &msg)
{
    // Make the message all upper case
    std::transform(msg.begin(), msg.end(), msg.begin(), ::toupper);

    // Encode the special characters as we like it
    msg = std::regex_replace(msg, std::regex("<BT>"), "=");
    msg = std::regex_replace(msg, std::regex("<BK>"), "b");
    msg = std::regex_replace(msg, std::regex("<KN>"), "k");
    msg = std::regex_replace(msg, std::regex("<SK>"), "s");
    msg = std::regex_replace(msg, std::regex("<AR>"), "+");
    msg = std::regex_replace(msg, std::regex("<KA>"), "a");

    // Remove all other unknown characters
    msg.erase(remove_if(msg.begin(), msg.end(),
                        [](const char &c) { return c != ' ' && morseCode.find(c) == morseCode.end(); }),
              msg.end());

    // Remove spaces, if there are too many of them
    msg = std::regex_replace(msg, std::regex("(\\s+)"), " ");
}

std::string messageToMorse(std::string &msg)
{
    refurbishMessage(msg);

    std::string morseString {};

    for (unsigned int i = 0; i < msg.length(); i++) {
        char c = msg[i];
        if (c == ' ') {
            morseString.push_back('w');
            continue;
        }

        // Ignore and continue with next char, if not found
        auto search = morseCode.find(c);
        if (search == morseCode.end()) {
            continue;
        }

        for (unsigned int j = 0; j < morseCode[c].length(); j++) {
            char m = morseCode[c][j];
            if (j == 0 && i > 0 && msg[i - 1] != ' ') {
                morseString.push_back('c');
            }

            morseString += m;

            if (j < morseCode[c].length() - 1) {
                morseString.push_back('i');
            }
        }
    }

    // Append word space if last char was not a blank
    if (msg.back() != ' ') {
        morseString.push_back('w');
    }

    return morseString;
}

std::string charToMorse(char ch) {
    std::string morseString {};

    if (ch == ' ') {
            morseString.push_back('w');
            return morseString;
        }

    for (unsigned int j = 0; j < morseCode[ch].length(); j++) {
            char m = morseCode[ch][j];

            morseString += m;

            if (j < morseCode[ch].length() - 1) {
                morseString.push_back('i');
            }
        }

    morseString.push_back('c');

    return morseString;

}