refactor code

pscat/pscat.c

@@ -1,12 +1,14 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
 #ifndef DONT_USE_SYSTEM_SYSEXITS
 #	include <sysexits.h>
 #else
-#	include "../include/sysexits.h"
+#	include "../sysexits/sysexits.h"
 #endif /* ifndef DONT_USE_SYSTEM_SYSEXITS */
 
-#include <stdio.h>
-#include <sys/wait.h>
-#include <unistd.h>
+#include "psargs.h"
 
 static char *program_name = "pscat";
 
@@ -16,56 +18,21 @@ static char *program_name = "pscat";
 #	define L_PAREN '['
 #	define R_PAREN ']'
 #else
-#	include "../include/ascii.h"
+#	include "../ascii/ascii.h"
 #	define L_PAREN ASCII_LEFT_SQUARE_BRACKET
 #	define R_PAREN ASCII_RIGHT_SQUARE_BRACKET
 #endif /* ifndef USE_ASCII_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))
-
-/* Verifies arguments to pscat are sensible. */
-static int
-check_arg(char **argv){
-	enum {
-		UNINITIALIZED = 0,
-		NORMAL = 1,
-		INLPAREN = 2
-	} s;
-	int terms;
-
-	for(s = UNINITIALIZED, terms = 0; *argv != NULL; ++argv)
-		switch(s){
-		case UNINITIALIZED: case NORMAL:
-			if(SCMPFLAT(*argv, L_PAREN))
-				s = INLPAREN;
-			else
-				return 0; /* syntax error */
-			break;
-		default: /* >= INLPAREN */
-			if(argv[0][1] == '\0'){
-				s -= (argv[0][0] == R_PAREN);
-				terms += (argv[0][0] == R_PAREN && s == NORMAL);
-				s += (argv[0][0] == L_PAREN);
-			}
-			break;
-		}
-
-	return terms;
-}
-
 int main(int argc, char *argv[]){
 	char **psstart;
 	int child;
 	int i;
-	int p;
 	int retval;
 	int terms;
 
 	retval = 0;
 
-	if((terms = check_arg(++argv)) == 0){
+	if((terms = check_arg(++argv, L_PAREN, R_PAREN)) == 0){
 		fprintf(stderr,
 			"Usage: %s \"[\" [utility [argument...]] \"]\" ...\n",
 			argv[0] == NULL ? program_name : argv[0]
@@ -75,18 +42,8 @@ int main(int argc, char *argv[]){
 
 	/* loop starts with *argv -> the next L_PAREN */
 	for(i = 0; i < terms; ++i){
-		psstart = ++argv;
-		p = 1;
-		while(p > 0){
-			++argv;
-			/* 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(*argv, L_PAREN))
-				++p;
-			else if(SCMPFLAT(*argv, R_PAREN))
-				--p;
-		}
+		psstart = argv + 1;
+		argv = corresponding_arg(argv, L_PAREN, R_PAREN);
 		/* *argv -> the corresponding R_PAREN. turn it into NULL to
 		 * terminate the argument list to send to execvp(3) */
 		*argv = NULL;