add support for +options to remove effect of -option

Signed-off-by: Mattias Andrée <maandree@member.fsf.org>

1 files changed, 78 insertions, 36 deletions

diff --git a/src/arg.h b/src/arg.h
index 8d235ba..3fe5145 100644
--- a/src/arg.h
+++ b/src/arg.h
@@ -1,41 +1,83 @@
-/*
- * Copy me if you can.
- * by 20h
+/**
+ * Copyright © 2016  Mattias Andrée <maandree@member.fsf.org>
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
  */
 
-#ifndef ARG_H__
-#define ARG_H__
 
+
+/**
+ * The name of the process.
+ */
 extern char *argv0;
 
-/* use main(int argc, char *argv[]) */
-#define ARGBEGIN	for (argv0 = *argv, argv++, argc--;\
-					argv[0] && argv[0][1]\
-					&& argv[0][0] == '-';\
-					argc--, argv++) {\
-				char argc_;\
-				char **argv_;\
-				int brk_;\
-				if (argv[0][1] == '-' && argv[0][2] == '\0') {\
-					argv++;\
-					argc--;\
-					break;\
-				}\
-				for (brk_ = 0, argv[0]++, argv_ = argv;\
-						argv[0][0] && !brk_;\
-						argv[0]++) {\
-					if (argv_ != argv)\
-						break;\
-					argc_ = argv[0][0];\
-					switch (argc_)
-
-#define ARGEND			}\
-			}
-
-#define ARGF()		((argv[0][1] == '\0' && argv[1] == NULL)?\
-				(char *)0 :\
-				(brk_ = 1, (argv[0][1] != '\0')?\
-					(&argv[0][1]) :\
-					(argc--, argv++, argv[0])))
-
-#endif
+
+
+/**
+ * Start command line parsing.
+ * 
+ * `argv` and `argc` must be available as given to `main`.
+ * The global variable `argv0` must be declare (not necessary
+ * the the same file) and will be set to `argv[0]`.
+ * 
+ * Only short options and "--" are supported. Short options
+ * may start with a '+', in which case `plus` will be 1.
+ * 
+ * @example
+ *     ARGBEGIN {
+ *     case 'a':  printf("%s\n", plus ? "+a" : "-a");                        break;
+ *     case 'b':  if (plus) usage(1); printf("-b\n");                        break;
+ *     case 'c':  if (plus) printf("+c\n"); else printf("-c %s\n", ARGF());  break;
+ *     default:   usage(1);                                                  break;
+ *     } ARGEND;
+ */
+#define ARGBEGIN  \
+do {  \
+	for (argv0 = *argv++, argc -= !!argv0; *argv; argv++, argc--) {  \
+		int plus = argv[0][0] == '+', next__ = 0;  \
+		if (((argv[0][0] != '-') && !plus) || (argv[0][1] == (plus ? '+' : '-'))) {  \
+			if ((argv[0][0] == argv[0][1]) && (argv[0][1] == '-')  && (argv[0][2] == '\0'))  \
+				argc--, argv++;  \
+			break;  \
+		}  \
+		for (argv[0]++; argv[0][0] && !next__;) {  \
+			switch (*(argv[0])++)
+
+/**
+ * End of command line parsing,
+ */
+#define ARGEND  \
+		}  \
+	}  \
+} while (0)
+
+/**
+ * Get the argument of the current option.
+ * Do not use more once per option.
+ * 
+ * The function `noreturn void usage(int)` must be available.
+ * `usage` shall exit if its argument is `1`.
+ * 
+ * @return  The argument of the current option.
+ */
+#define ARGF()  \
+	(next__ = 1, argv[0][0] ? (argv[0])  \
+	 : (argv++, (argv[0]    ? (argc--, argv[0])  \
+	                        : (usage(1), NULL))))
+