queue_of_queues.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include "../../include/queue.h"

//insert an element in tail queue
#define INSERT_TOKEN(STR) \
	do { \
		/*create new element*/ \
		tok_len = strlen(STR); \
		telt = malloc(sizeof(struct tentry)); \
		telt->name = malloc(tok_len + 1); \
		memcpy(telt->name, STR, tok_len); \
		telt->name[tok_len] = '\0'; \
		\
		STAILQ_INSERT_TAIL(thead, telt, pts); \
		} \
	while (0)

//insert an element in tail queue
#define INSERT_NONT(STR) \
	do { \
		bool found;\
		\
		/*search for new element in tail queue*/ \
		found = false; \
		STAILQ_FOREACH(nelt, &hnonterminals, pts) \
			if (!strcmp(STR, nnelt->name)) { \
				found = true; \
				break; \
				} \
		/*if it wasn't found then create and insert it at the head*/ \
		if (found == false) { \
			/*name of nonterminal*/ \
			tok_len = strlen(STR); \
			nnelt = malloc(sizeof(struct nentry)); \
			nnelt->name = malloc(tok_len + 1); \
			memcpy(nnelt->name, STR, tok_len); \
			nnelt->name[tok_len] = '\0'; \
			nnelt->pruned = false; \
			/*head of tokens' tree*/ \
			thead = (struct tentryhead *)malloc(sizeof(struct tentryhead)); \
			thead->stqh_first = NULL; \
			thead->stqh_last = thead->stqh_first; \
			STAILQ_INIT(thead); \
			nnelt->tokens = thead; \
			\
			STAILQ_INSERT_TAIL(&hnonterminals, nnelt, pts); \
			} \
		} \
	while (0)


//macro for printing error messages easily
#define error(...) fprintf(stderr, "error: %name: %i: %name\n", __func__, __LINE__, __VA_ARGS__)

struct tentry {
	STAILQ_ENTRY(tentry) pts;	//pointers
	char *name;					//null-terminated string
	};
    
struct nentry {
	STAILQ_ENTRY(nentry) pts;	//pointers
	char *name;					//null-terminated string
	bool pruned;				//was this nonterminal definition pruned?
	struct tentryhead *tokens;	//pointer to tail queue of tokens
	};

int main (int argc, char** argv)
{
    unsigned tok_len;
    char buffer[] = "tok1 tok2 tok3 tok4 tok5 tok6";
    const char token_seps[] = " ";
    char *tag;
    
    /*element in single-linked tail queue of tokens, new and existing elements in single-linked
    tail queue of nonterminals*/
    struct tentry *telt;
	struct nentry *nnelt, *nelt;
 
   	//initialization of sturctures
	STAILQ_HEAD(tentryhead, tentry);
	struct tentryhead *thead;
	STAILQ_HEAD(nentryhead, nentry) hnonterminals = STAILQ_HEAD_INITIALIZER(hnonterminals);
	STAILQ_INIT(&hnonterminals);
    
    //logic goes here------------------------------------------------------------------------------
    
    //begin processing of grammar rules from their start
	if ( (tag = strtok(buffer, token_seps)) != NULL) {
	
		do {
			//printf("tag = %s\n", tag);
			if ( (!strcmp(tag, "tok1")) || (!strcmp(tag, "tok4")) ) {
				INSERT_NONT(tag);
				}
			else {
				INSERT_TOKEN(tag);
				}
			
		} while ( (tag = strtok(NULL, token_seps)) != NULL);
		
		}
    
    printf("output: \n");
    STAILQ_FOREACH(nelt, &hnonterminals, pts) {
		printf("\n%s: ", nelt->name);
		STAILQ_FOREACH(telt, (struct tentryhead *)nelt->tokens, pts)
			printf("%s ", telt->name);
		}
	printf("\n");
	//free entries and delete tail queue
	while (!STAILQ_EMPTY(&hnonterminals)) {
		nelt = STAILQ_FIRST(&hnonterminals);
		STAILQ_REMOVE_HEAD(&hnonterminals, pts);
		
		while (!STAILQ_EMPTY((struct tentryhead *)nelt->tokens)) {
			telt = STAILQ_FIRST((struct tentryhead *)nelt->tokens);
			STAILQ_REMOVE_HEAD((struct tentryhead *)nelt->tokens, pts);
			
			free(telt->name);
			free(telt);
			}
		
		free(nelt->tokens);
		free(nelt->name);
		free(nelt);
	
		}
    

 
    return 0;
}