// morse.cpp

#include "morse.h"
#include <cstring>
#include <iostream>

// This array has one element per printable character
// starting with ' '. If I was trying for space and speed efficiency, 
// I could represent the same information using just 40 characters,
// one for each of the Morse codes. 
const char Morse::charm[95][7] = {
      	"", "", "", "", "", "", "", "",
    "", "", "", "", "--..--", "", ".-.-.-", "", "-----", ".----",
    "..---", "...--", "....-", ".....", "-....", "--...", "---..",
					"----.", "---...", "-.-.-.",
    "", "", "", "", "", ".-", "-...", "-.-.", "-..", ".",
    "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--", "-.", "---",
    ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--", "-..-", "-.--",
    "--..", "", "", "", "", "", "", ".-", "-...", "-.-.", 
    "-..", ".", "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--", 
    "-.", "---", ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--", 
    "-..-", "-.--", "--..", "", "", "", ""
      };

// mc has one character per morse code encoding as a number.
// In the encoding '.' is represented as '0', '-' as '1'.
// The encoded sequence is preceded by a '1' and it is interpreted as 
// a binary number.
const char Morse::mc[128] = 
		"--ETIANMSURWDKGOHVF-"
		"L-PJBXCYZQ--54-3---2"
		"-------16-------7---"
		"8-90----------------"
		"-----.--------------"
		"------;--------,----"
		":------";

const char * Morse::char2morse(char c)
{
    return charm[int(c)-int(' ')];
}

char Morse::morse2char(const char * s) 
{
	int sum = 1;
	for (const char * p = s; (*p == '.') || (*p == '-'); p++)
		sum = 2*sum + (((*p)=='.')?0:1);
	return mc[(sum<127)?sum:0];
}