my solution to lab5

lab/inc/args.h

@@ -0,0 +1,82 @@
+#ifndef JOS_INC_ARGS_H
+#define JOS_INC_ARGS_H
+
+struct Argstate;
+
+// JOS command-line parsing functions.
+
+// Initializes the Argstate buffer from argc and argv.
+// (Note: it is safe to use a 'const char **' for argv.)
+void argstart(int *argc, char **argv, struct Argstate *args);
+
+// Returns the next flag in the argument list,
+// or -1 if there are no more flags.
+//
+// Flags stop at a non-flag (anything that doesn't start with '-'),
+// at the end of the argument list, before "-", or after "--",
+// whichever comes first.  Any "--" argument is not returned.
+//
+// Consumes arguments from the argc/argv array passed in to argstart.
+// If you argstart with an argc/argv array of ["sh", "-i", "foo"],
+// the first call to argnext will return 'i' and change the array to
+// ["sh", "foo"].  Thus, when argnext returns -1, the argc/argv array
+// contains just the non-flag arguments.
+int argnext(struct Argstate *);
+
+// Returns the next value for the current flag, or 0 if it has no value.
+// For example, given an argument list ["-fval1", "val2", "val3"],
+// a call to argnext() will return 'f', after which repeated calls to
+// argnextvalue will return "val1", "val2", and "val3".
+// Consumes arguments from the argc/argv array.
+char *argnextvalue(struct Argstate *);
+
+// Returns the current flag's value, or 0 if it has no value.
+// Behaves like argnextvalue, except that repeated calls to argvalue will
+// return the same value.
+char *argvalue(struct Argstate *);
+
+// Example:
+//
+//	#include <inc/lib.h>
+//
+//	void
+//	umain(int argc, char **argv)
+//	{
+//		int i;
+//		struct Argstate args;
+//
+//		argstart(&argc, argv, &args);
+//		while ((i = argnext(&args)) >= 0)
+//			switch (i) {
+//			case 'r':
+//			case 'x':
+//				cprintf("'-%c' flag\n", i);
+//				break;
+//			case 'f':
+//				cprintf("'-f %s' flag\n", argvalue(&args));
+//				break;
+//			default:
+//				cprintf("unknown flag\n");
+//			}
+//
+//		for (i = 1; i < argc; i++)
+//			cprintf("argument '%s'\n", argv[i]);
+//	}
+//
+// If this program is run with the arguments
+// ["-rx", "-f", "foo", "--", "-r", "duh"]
+// it will print out
+//	'-r' flag
+//	'-x' flag
+//	'-f foo' flag
+//	argument '-r'
+//	argument 'duh'
+
+struct Argstate {
+	int *argc;
+	const char **argv;
+	const char *curarg;
+	const char *argvalue;
+};
+
+#endif