cat(1p): cleanup

src/cat.c

@@ -20,6 +20,7 @@
 
 #include <errno.h>
 #include <sysexits.h>
+#include <sys/stat.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -29,26 +30,26 @@ void cat(FILE *file, bool u) {
 	int p = 0; /* index counter for bytes in buffered reading */
 	char buf[4096]; /* buffer for buffered reading */
 
-	while (byte != EOF) {
-		byte = fgetc(file);
-
-		if (u) {
+	if (u) {
+		while (byte != EOF) {
+			byte = fgetc(file);
 			putchar(byte);
-		} else {
+		}
+	} else {
+		while (byte != EOF) {
+			byte = fgetc(file);
 			if (p > sizeof(buf)) {
 				fputs(buf, stdout);
 				p = 0;
+			} else {
+				buf[p] = byte;
+				p += 1;
 			}
-
-			buf[p] = byte;
-			p += 1;
 		}
+
+		fwrite(buf, 1, p, stdout);
+		fflush(stdout);
 	}
-
-	fwrite(buf, 1, p, stdout);
-	fflush(stdout);
-
-	if (file != stdin) { fclose(file); }
 }
 
 int main(int argc, char *argv[]) {
@@ -91,11 +92,20 @@ int main(int argc, char *argv[]) {
 	}
 	
 	FILE *file;
+	struct stat stats;
+
 	for (i = optind; i < argc; i++) {
-		if (argv[i][0] == '-' && argv[i][1] != '\0') {
-			continue;
-		} else if (argv[i][0] == '-' && argv[i][1] == '\0') {
-			file = stdin;
+		if (argv[i][0] == '-') {
+			switch (argv[i][1]) {
+				case '\0':
+					file = stdin;
+					break;
+				default:
+					continue;
+			}
+		} else if (stat(argv[i], &stats) == 0 && S_ISDIR(stats.st_mode)) {
+			fprintf(stderr, "%s: %s: Is a directory.\n", argv[0], argv[i]);
+			return EX_NOINPUT;
 		} else if ((file = fopen(argv[i], "r")) == NULL) {
 			switch (errno) {
 				case EACCES:
@@ -118,7 +128,9 @@ int main(int argc, char *argv[]) {
 					return EX_UNAVAILABLE;
 			}
 		}
+
 		cat(file, u);
+		if (file != stdin) { fclose(file); }
 	}
 
 	return EX_OK;