Utilities.h

char *array[5]; // Array of tokens
void readCommand(char *commandString){ // A utility function used for splitting given command on parts -  string token, use of space as a divider
	
	int i = 0; char *token;	
	// Array[i] holds the following
	array[0] = NULL; // Operation (encode. decode)
	array[1] = NULL; // Target (file, console)
	array[2] = NULL; // Input file path
	array[3] = NULL; // Optional operation ('write' to the file)
	array[4] = NULL; // Output file path
	token = strtok(commandString, " ");
		while (token != NULL){
			array[i++] = token;
			token = strtok (NULL, " ");
	}
}
char *processFileName(char *filename, int fileType){
 
	/* The utility function for validating file name provided by the user.
	   It allowes for entering the file names with or without their extenstions,
	   and helps to avoid mistakes in naming files e.g. file.dat.dat */
	
	char extension[][5]={".dat",".txt"};  // Files extension
	char ext[]={".ext"};				  // Holds the extension provided by user
	int len = strlen(filename);			  // Save length of path
	char* pos;							  // Position of the character
	pos = (filename+len-4);				  // Make pos point to the 4'th last char of string '.'
	strcpy(ext, pos);					  // Get last 4 characters '.ext'
	if(!strcmp(ext,extension[fileType])){ // Compare to the standard extensions types
		*pos='\0';						  // If standard, delete extension provided by the user
	}	
	char filepath[50];					  // Holds the file path
	strcpy(filepath, filename);			  // Copy file path
	strcat(filepath, extension[fileType]);// Add standard extension
	return _strdup(filepath);
 
}
/* Used in writing to file operations. Function checks if file already exists in the given location,
   displays the warning message and prompts for decision on overwriting/terminating operation.
   It returns an integer value used as condition within runCommand() function. This function also
   validates and manage the files extensions distribution */
int validatePath(char *path, int fileType){ 
	
	char choice;						  // Holds user choice on overwriting existing file
	int write;							  // Holds the decision on further action
	
	char filepath[50];					  // Holds the file path
	strcpy(filepath, processFileName(path, fileType)); // manage the file extension
	FILE *fptr = fopen(filepath, "rb");	  // Check if file exists
	if ( fptr  != NULL ) {				  // If exists
		fclose(fptr);
		printf("\n -- WARNING ! : File already exists! 'y' - yes, else - no \n");
		printf("\n      Overwrite? ");
		scanf("%c", &choice);			  // Ask for decision
		if(choice=='y'){
			write = 1;					  // Store the decision
		}
		else {
			write = 0;
		}
 
	}	
	else if ( fptr  == NULL ){			  // If doesn't exist continue writing file
		write=1;	
	} 
	
	return write;
 
}
 
// PRINTING FUNCTIONS----------------------------------------------------------------------------------------------------------------------------
 
/* Prints the table of the unique characters,their frequencies and binary prefixes (Huffman Codes)
   Function is performing additional sort of characterBINARY array created in HuffmanEncoding.h
   in order to match codes with their corresponding letters
*/
void print_Table(char character[], int frequency[], char string[], int size  ){ 
		
		// Attach the binary codes to the corresponding letters in order to print the table correctly
		char temp2[250][20];									// Temp array used for printing codes in the table
		for (int i = 0; i < strlen(character); ++i){		    // For each of unique characters in 'character' array
			for(int j=0; j < strlen(characterASCII); ++j ){ 	// Scan through 'characterASCII' array
				if(character[i]==characterASCII[j]){ 			// If match found
					strcpy(temp2[i], characterBINARY[j]);		// Copy 'characterBinary' data in the same index what 'character' is located
				}
			}
		}
 
	
		printf("\n\n    Table >>> BINARY prefixes:\n\n");
		printf("       ID |  Char | Freq  | Binary Code\n");
		printf("       -------------------------------- \n");
		for (int i=0; i < strlen(character); i++){
			printf("    %5d | %5c | %5d |  %s  \n", (i+1), character[i], frequency[i],temp2[i]);
		}
		printf("       ________________________________ \n");
		printf("\n     Total characters: %d ; Unique characters: %d", strlen(string), size);
		printf("\n\n");
 
}
 
/* Prints the error messages based on given circumstance. It indicates the reason of error */
void printErrorCode(int errorCode, char *filePath){ // Function prints the error messages
 
	switch(errorCode){
 
		case 1:printf("\n -- syntax error 1 : The command was not recognised!  | type help for the commands list\n\n");break;
		case 2:printf("\n -- syntax error 2 : Missing input file path  \n");break;
		case 3:printf("\n -- syntax error 3 : Missing output file path \n");break;
		case 4:printf("\n -- access error 4 : The '%s' file does not exist at this location !\n\n",filePath);break;
		case 5:printf("\n --  limit error   : There must be atleast 2 unique characters !\n\n");
			   printf("        --q to Quit , --help for Help\n\n");break;
		case 6:printf("\n -- syntax error 5 : No target specyfied! \n");break;
		case 7:printf("\n\n\n -- access error : Can't save '%s' file : ACCES DENIED!\n\n",filePath);break;
	}
}
 
/* Prints the 'Help' informations */
void print_Help(){ // 
 
				printf("\n\n  COMMAND LIST \n\n");	
				printf("    ----------------------------------------------------------- \n\n");
				printf("    encode                | run encoding operation \n\n");
				printf("    decode                | run decoding operation \n\n");
				printf("    file  <path>          | reads file from the given location \n\n");
				printf("    console               | reads text from the console \n\n");
				printf("    write <path>          | writes file to the given location\n\n\n");
		
				printf("    clear                 | clear the screen \n\n");
				printf("    help                  | Help \n\n");
				printf("    exit                  | Exit program \n\n");
				printf("    ----------------------------------------------------------- \n\n");
				printf("    Use of the commands:\n\n");
				printf("        1.  encode file <file path>.txt                \n");
				printf("        2.  encode file <file path>.txt write file.dat \n");
				printf("        3.  encode console                             \n");
				printf("        4.  encode console <file path>.dat             \n");
				printf("        5.  decode <file path>.dat                     \n");
				printf("        6.  decode <file path>.dat write file.txt      \n");
				printf("     NOTE: The files extensions are assigned automaticly\n\n");
}
/* Prints header of the program */
void print_Header(){ 
	
				printf("\n HUFFMAN ENCODING-DECODING\n");
				printf("_____________________________________________________\n\n");
				printf(" ----------------------\n");
				printf("  Type 'help' for Help \n");
				printf(" ----------------------\n");					
}
// END OF PRINTING FUNCTIONS---------------------------------------------------------------------------------------------------------------------