#include <stddef.h> /* size_t */

#include "libpsargs.h"

/* Test string containing { c, '\0' } without iteration.
 * Theoretically saves a little bit of time compared to strcmp(3). */
#define SCMPFLAT(a, b) (*(a) != '\0' && *((a)+1) == '\0' && *(a) == (b))

int
check_arg(char **args){
	enum {
		UNINITIALIZED = 0,
		NORMAL = 1,
		INLPAREN = 2
	} s;
	int terms;

	for(s = UNINITIALIZED, terms = 0; *args != NULL; ++args)
		switch(s){
		case UNINITIALIZED: case NORMAL:
			if(SCMPFLAT(*args, l))
				s = INLPAREN;
			else
				return 0; /* syntax error */
			break;
		default: /* >= INLPAREN */
			/* decrement s if on an rparen, increment if on lparen
			 * increment terms if on an rparen */
			if(args[0][1] == '\0'){
				s += (args[0][0] == L_PAREN)
					- (args[0][0] == R_PAREN);
				terms +=
					(args[0][0] == R_PAREN && s == NORMAL);
			}
			break;
		}

	/* make sure nothing's open */
	return terms * (s == NORMAL);
}

char **
corresponding_arg(char **arg){
	size_t p;

	for(p = 1; p > 0;){
		++arg;
		/* branching here potentially saves a comparison.
		 * this seems like the most optimal way to do this,
		 * maybe it isn't, i don't care too much */
		if(SCMPFLAT(*arg, L_PAREN))
			++p;
		else if(SCMPFLAT(*arg, R_PAREN))
			--p;
	}

	return arg;
}

#undef SCMPFLAT