/* --------------------------------------------------- */
/* ---                Pocitanie slov               --- */
/* --------------------------------------------------- */

/* ---------------------------------------------------
          zapocet z C pre 3MI december 1996
   ---------------------------------------------------
   
   Uloha c.1:
   ----------
     - upravte program tak, aby ako oddelovacie znaky
       jednotlivych slov akceptoval aj znaky:
       '(', ')', '{', '}', ',', '.', '/'
   
   Uloha c.2:
   ----------
     - upravte program tak, aby bol jeho vystup 
       (vypisany zoznam) usporiadany podla percentualnej
       pocetnosti prislusneho slova 
       ( #(vyskytov slova) / #(vsetkych slov)
   --------------------------------------------------- */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* ---  maximalna dlzka slova  --- */
#define	MAX_LEN	1024

/* ---  uchovanie slov a ich pocetnosti  --- */
typedef 
	struct Words_Structure {
		char * word;
		int    count;
		struct Words_Structure * next;
	} WORDS;

typedef WORDS * WORDS_PTR;

/* ---  prototypy funckii  --- */

/* ---
   nacita slovo z 'input' a ulozi ho do 'buffer'
   ak prida na koniec suboru vrati NULL
   --- */
char * get_word(FILE * input, char * buffer);

/* ---  
   prida slovo 'new_word' do na zaciatok 'ptr'
   --- */
void add_word(WORDS_PTR * ptr, char * new_word);

/* ---  
   ak existuje polozka zoznamu 'ptr' obsahujuca
   slovo 'word' tak vrati smernik na nu, inak NULL
   --- */
WORDS_PTR find_word(WORDS_PTR ptr, char * word);

/* ---
   vypise polozky zoznamu 'ptr'
   --- */
void print_words(WORDS_PTR ptr);

/* ---
   zmaze polozky zoznamu 'ptr' a jeho hodnotu nastavi na NULL
   --- */
void delete_words(WORDS_PTR * ptr);


/* ---  main  --- */
int main(int argc, char * argv[]) {
	/* ---  Deklaracia premmenych  --- */
	char buffer[MAX_LEN + 1];
	WORDS_PTR words;
	FILE * input;
	
	if (argc <= 1) {
		/* --- 
		   ak nemame dost zadanych argumentov budeme
		   citat zo standardneho vstupu 
		   --- */
		input = stdin;
	} else {
		/* ---
		   otvor subor zadany z prikazoveho riadku na citanie
		   --- */
		argc--;
		argv++;
		input = fopen(argv[0], "r");
		if (!input) {
			printf("Nemozem nasjst, alebo otvorit zadany subor !\n");
			return -1;
		}
	}
	
	/* ---  na zaciatku je zoznam prazdny  --- */
	words = NULL;
	
	/* ---
	   pokial nie je koniec vstupu pridavaj slova do zoznamu
	   --- */
	while (get_word(input, buffer))
		add_word(&words, buffer);
	
	/* ---  vypis vysledok  --- */
	printf("Pocetnost slov: \n");
	print_words(words);
	
	/* ---  zmaz polozky zoznamu  --- */
	delete_words(&words);

	/* ---
	   ak bol vstup citany zo suboru treba ho zavriet
	   --- */
	if (input != stdin)
		fclose(input);

	/* ---
	   treba vratit vysledok cinnosti programu 
	   --- */
	return 0;
}


/* ---  nacitanie slova zo vstupu  --- */
char * get_word(FILE * input, char * buffer) {
	int c, len = 0;
	buffer[0] = 0;
	
	/* ---  preskoc prazdne znaky  --- */
	while((c = fgetc(input)) != EOF)
		if (c != ' ' && c != '\t' && c != '\n')
			break;
	
	/* ---  ak je koniec suboru vrat NULL  --- */
	if (feof(input))
		return NULL;
	
	/* ---  chyba ?  --- */
	if (ferror(input)) {
		printf("Chyba pri citani suboru !\n");
		exit(-1);
	}
	
	/* ---  pokial nie je oddelovaci znak citaj do bufra  --- */
	do {
		if (c == ' ' || c == '\t' || c == '\n')
			break;
		buffer[len ++] = (char)c;
		buffer[len] = 0;
	} while((c = fgetc(input)) != EOF && len < MAX_LEN);

	/* ---  vrat smernik buffer  --- */
	return buffer;
}

/* ---  pridanie slova do zoznamu  --- */
void add_word(WORDS_PTR * ptr, char * new_word) {
	WORDS_PTR w = NULL;
	
	/* ---  ak uz toto slovo je v zozname  --- */
	if ((w = find_word(*ptr, new_word)) != NULL) {
		/* ---  inkrementuj pocet jeho vyskytov  --- */
		w->count ++;
	} else {
		/* ---  inak vyrob novy zaznam s tymto slovom  --- */
		w = (WORDS_PTR)malloc(sizeof(WORDS));
		memset(w, 0, sizeof(WORDS));
		w->word = (char *)malloc(strlen(new_word) +1);
		strcpy(w->word, new_word);
		w->count = 1;
		w->next = *ptr;
		*ptr = w;
	}
}

/* ---  prehladanie zoznamu  --- */
WORDS_PTR find_word(WORDS_PTR ptr, char * word) {
	while (ptr) {
		/* ---  rovnake slovo ?  --- */
		if (!strcmp(word, ptr->word))
			/* ---  ak ano vrat smernik na polozku  --- */
			return ptr;
		ptr = ptr->next;
	}
	/* ---  polozka s tymto slovom neexistuje vrat NULL  --- */
	return NULL;
}

/* ---  vypis polozky zoznamu  --- */
void print_words(WORDS_PTR ptr) {
	while (ptr) {
		printf("%s (%i)\n", ptr->word, ptr->count);
		ptr = ptr->next;
	}
}

/* ---  zmaz zoznam  --- */
void delete_words(WORDS_PTR * ptr) {
	WORDS_PTR tmp, fre = * ptr;
	while (fre) {
		tmp = fre->next;
		free(fre->word);
		free(fre);
		fre = tmp;
	}
	*ptr = NULL;
}