cat(1p): refactor to get no args working

src/cat.c

@@ -27,68 +27,7 @@
 #include <string.h>
 #include <unistd.h>
 
-int main(int argc, char *argv[]) {
+void cat(FILE *file, bool u) {
-	bool u = false;
-	int opt;
-
-	extern int optind;
-	while ((opt = getopt(argc, argv, "u")) != -1) {
-		switch (opt) {
-			/*
-			 * From cat(1p):
-			 *
-			 * -u        Write bytes from the input file to the standard output
-			 *           without delay as each is read.
-			 */
-			case 'u':
-				u = true;
-				break;
-			default:
-				printf("Usage: %s (-u) file...\n", argv[0]);
-				return EX_USAGE;
-		}
-	}
-
-	int i = 1;
-	FILE *file;
-
-	for (i = optind; i < argc; i++) {
-	  /*
-		 * From cat(1p):
-		 *
-		 * file      A pathname of an input file. If no file operands are
-		 *           specified, the standard input shall be used. If a file is
-		 *           '-', the cat utility shall read from the standard input at
-		 *           that point in the sequence. The cat utility shall not close
-		 *           and reopen standard input when it is referenced in this way,
-		 *           but shall accept multiple occurrences of '-' as a file
-		 *           operand.
-		 */
-		if (argv[i] == "-" || argc == 1) {
-			file = stdin;
-		} else if ((file = fopen(argv[i], "r")) == NULL) {
-			switch (errno) {
-				case EACCES:
-					printf("%s: %s: Permission denied.\n", argv[0], argv[i]);
-					return EX_NOINPUT;
-				case EISDIR:
-					printf("%s: %s: Is a directory.\n", argv[0], argv[i]);
-					return EX_NOINPUT;
-				case ELOOP:
-					printf("%s: %s: Is a symbolic link loop.\n", argv[0], argv[i]);
-					return EX_UNAVAILABLE;
-				case EMFILE:
-					printf("%s: Internal error.\n", argv[0]);
-					return EX_SOFTWARE;
-				case ENOENT: case ENOTDIR: case ENXIO:
-					printf("%s: %s: No such file or directory.\n", argv[0], argv[i]);
-					return EX_NOINPUT;
-				default:
-					printf("%s: Unknown error.\n", argv[0]);
-					return EX_UNAVAILABLE;
-			}
-		}
-
 	int byte = 0; /* variable for storing bytes as they are read */
 	int p = 0; /* index counter for bytes in buffered reading */
 	char buf[4096]; /* buffer for buffered reading */
@@ -115,5 +54,75 @@ int main(int argc, char *argv[]) {
 	if (file != stdin) { fclose(file); }
 }
 
+int main(int argc, char *argv[]) {
+	bool u = false;
+	int opt;
+	int i;
+
+	extern int optind;
+	while ((opt = getopt(argc, argv, "u")) != -1) {
+		switch (opt) {
+			/*
+			 * From cat(1p):
+			 *
+			 * -u        Write bytes from the input file to the standard output
+			 *           without delay as each is read.
+			 */
+			case 'u':
+				u = true;
+				break;
+			default:
+				printf("Usage: %s (-u) file...\n", argv[0]);
+				return EX_USAGE;
+		}
+	}
+
+	/*
+	 * From cat(1p):
+	 *
+	 * file      A pathname of an input file. If no file operands are
+	 *           specified, the standard input shall be used. If a file is
+	 *           '-', the cat utility shall read from the standard input at
+	 *           that point in the sequence. The cat utility shall not close
+	 *           and reopen standard input when it is referenced in this way,
+	 *           but shall accept multiple occurrences of '-' as a file
+	 *           operand.
+	 */
+
+	if (optind == argc) {
+		cat(stdin, u);
+	}
+	
+	FILE *file;
+	for (i = optind; i < argc; i++) {
+		if (argv[i][0] == '-' && argv[i][1] != '\0') {
+			continue;
+		} if (strcmp(argv[i], "-") == 0) {
+			file = stdin;
+		} else if ((file = fopen(argv[i], "r")) == NULL) {
+			switch (errno) {
+				case EACCES:
+					printf("%s: %s: Permission denied.\n", argv[0], argv[i]);
+					return EX_NOINPUT;
+				case EISDIR:
+					printf("%s: %s: Is a directory.\n", argv[0], argv[i]);
+					return EX_NOINPUT;
+				case ELOOP:
+					printf("%s: %s: Is a symbolic link loop.\n", argv[0], argv[i]);
+					return EX_UNAVAILABLE;
+				case EMFILE:
+					printf("%s: Internal error.\n", argv[0]);
+					return EX_SOFTWARE;
+				case ENOENT: case ENOTDIR: case ENXIO:
+					printf("%s: %s: No such file or directory.\n", argv[0], argv[i]);
+					return EX_NOINPUT;
+				default:
+					printf("%s: Unknown error.\n", argv[0]);
+					return EX_UNAVAILABLE;
+			}
+		}
+		cat(file, u);
+	}
+
 	return EX_OK;
 }