getpot: add support for "a+" specifier for nonnegative int parameters.

By Vladimir Dronnikov <dronnikov at gmail.com>.
fdisk and top are converted as an example.

function                                             old     new   delta
getopt32                                            1340    1370     +30
top_main                                            1137    1120     -17
fdisk_main                                          3033    2949     -84
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 30/-101)           Total: -71 bytes

3 files changed, 55 insertions, 44 deletions

diff --git a/libbb/getopt32.c b/libbb/getopt32.c
index 80d5d2822..46807a3b6 100644
--- a/libbb/getopt32.c
+++ b/libbb/getopt32.c
@@ -220,6 +220,14 @@ Special characters:
  "x--x" Variation of the above, it means that -x option should occur
         at most once.
 
+ "a+:"  A plus after a char in opt_complementary means that the parameter
+        for this option is a nonnegative integer. It will be processed
+        with xatoi_u() - allowed range is 0..INT_MAX.
+
+        int param;  // "unsigned param;" will also work
+        opt_complementary = "p+";
+        getopt32(argv, "p:", &param);
+
  "a::"  A double colon after a char in opt_complementary means that the
         option can occur multiple times. Each occurrence will be saved as
         a llist_t element instead of char*.
@@ -275,14 +283,20 @@ Special characters:
 
 const char *opt_complementary;
 
+enum {
+	PARAM_STRING,
+	PARAM_LIST,
+	PARAM_INT,
+};
+
 typedef struct {
-	int opt;
-	int list_flg;
+	unsigned char opt_char;
+	smallint param_type;
 	unsigned switch_on;
 	unsigned switch_off;
 	unsigned incongruously;
 	unsigned requires;
-	void **optarg;               /* char **optarg or llist_t **optarg */
+	void **optarg;  /* char**, llist_t** or int *. */
 	int *counter;
 } t_complementary;
 
@@ -337,12 +351,14 @@ getopt32(char **argv, const char *applet_opts, ...)
 	if (*s == '+' || *s == '-')
 		s++;
 	while (*s) {
-		if (c >= 32) break;
-		on_off->opt = *s;
+		if (c >= 32)
+			break;
+		on_off->opt_char = *s;
 		on_off->switch_on = (1 << c);
 		if (*++s == ':') {
 			on_off->optarg = va_arg(p, void **);
-			while (*++s == ':') /* skip */;
+			while (*++s == ':')
+				continue;
 		}
 		on_off++;
 		c++;
@@ -375,11 +391,12 @@ getopt32(char **argv, const char *applet_opts, ...)
 		for (l_o = long_options; l_o->name; l_o++) {
 			if (l_o->flag)
 				continue;
-			for (on_off = complementary; on_off->opt != 0; on_off++)
-				if (on_off->opt == l_o->val)
+			for (on_off = complementary; on_off->opt_char; on_off++)
+				if (on_off->opt_char == l_o->val)
 					goto next_long;
-			if (c >= 32) break;
-			on_off->opt = l_o->val;
+			if (c >= 32)
+				break;
+			on_off->opt_char = l_o->val;
 			on_off->switch_on = (1 << c);
 			if (l_o->has_arg != no_argument)
 				on_off->optarg = va_arg(p, void **);
@@ -422,11 +439,15 @@ getopt32(char **argv, const char *applet_opts, ...)
 			s++;
 			continue;
 		}
-		for (on_off = complementary; on_off->opt; on_off++)
-			if (on_off->opt == *s)
+		for (on_off = complementary; on_off->opt_char; on_off++)
+			if (on_off->opt_char == *s)
 				break;
 		if (c == ':' && s[2] == ':') {
-			on_off->list_flg++;
+			on_off->param_type = PARAM_LIST;
+			continue;
+		}
+		if (c == '+' && (s[2] == ':' || s[2] == '\0')) {
+			on_off->param_type = PARAM_INT;
 			continue;
 		}
 		if (c == ':' || c == '\0') {
@@ -454,8 +475,8 @@ getopt32(char **argv, const char *applet_opts, ...)
 				else
 					pair_switch = &(pair->switch_off);
 			} else {
-				for (on_off = complementary; on_off->opt; on_off++)
-					if (on_off->opt == *s) {
+				for (on_off = complementary; on_off->opt_char; on_off++)
+					if (on_off->opt_char == *s) {
 						*pair_switch |= on_off->switch_on;
 						break;
 					}
@@ -508,9 +529,9 @@ getopt32(char **argv, const char *applet_opts, ...)
 #endif
 		c &= 0xff; /* fight libc's sign extension */
  loop_arg_is_opt:
-		for (on_off = complementary; on_off->opt != c; on_off++) {
+		for (on_off = complementary; on_off->opt_char != c; on_off++) {
 			/* c==0 if long opt have non NULL flag */
-			if (on_off->opt == 0 && c != 0)
+			if (on_off->opt_char == '\0' && c != '\0')
 				bb_show_usage();
 		}
 		if (flags & on_off->incongruously)
@@ -521,8 +542,10 @@ getopt32(char **argv, const char *applet_opts, ...)
 		flags ^= trigger;
 		if (on_off->counter)
 			(*(on_off->counter))++;
-		if (on_off->list_flg) {
+		if (on_off->param_type == PARAM_LIST) {
 			llist_add_to_end((llist_t **)(on_off->optarg), optarg);
+		} else if (on_off->param_type == PARAM_INT) {
+			*(unsigned*)(on_off->optarg) = xatoi_u(optarg);
 		} else if (on_off->optarg) {
 			*(char **)(on_off->optarg) = optarg;
 		}
@@ -550,7 +573,7 @@ getopt32(char **argv, const char *applet_opts, ...)
 		free(argv[1]);
 #endif
 	/* check depending requires for given options */
-	for (on_off = complementary; on_off->opt; on_off++) {
+	for (on_off = complementary; on_off->opt_char; on_off++) {
 		if (on_off->requires && (flags & on_off->switch_on) &&
 					(flags & on_off->requires) == 0)
 			bb_show_usage();
diff --git a/procps/top.c b/procps/top.c
index 4df58f227..37b6a0cdb 100644
--- a/procps/top.c
+++ b/procps/top.c
@@ -740,7 +740,7 @@ int top_main(int argc, char **argv)
 	int count, lines, col;
 	unsigned interval;
 	int iterations;
-	char *sinterval, *siterations;
+	char *sinterval;
 	SKIP_FEATURE_TOPMEM(const) unsigned scan_mask = TOP_MASK;
 #if ENABLE_FEATURE_USE_TERMIOS
 	struct termios new_settings;
@@ -757,15 +757,12 @@ int top_main(int argc, char **argv)
 	iterations = 0; /* infinite */
 
 	/* do normal option parsing */
-	opt_complementary = "-";
-	getopt32(argv, "d:n:b", &sinterval, &siterations);
+	opt_complementary = "-:n+";
+	getopt32(argv, "d:n:b", &sinterval, &iterations);
 	if (option_mask32 & 0x1) {
 		/* Need to limit it to not overflow poll timeout */
 		interval = xatou16(sinterval); // -d
 	}
-	if (option_mask32 & 0x2)
-		iterations = xatoi_u(siterations); // -n
-	//if (option_mask32 & 0x4) // -b
 
 	/* change to /proc */
 	xchdir("/proc");
diff --git a/util-linux/fdisk.c b/util-linux/fdisk.c
index cd053b876..c98a74fc0 100644
--- a/util-linux/fdisk.c
+++ b/util-linux/fdisk.c
@@ -2754,7 +2754,6 @@ unknown_command(int c)
 int fdisk_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int fdisk_main(int argc, char **argv)
 {
-	char *str_b, *str_C, *str_H, *str_S;
 	unsigned opt;
 	/*
 	 *  fdisk -v
@@ -2776,8 +2775,9 @@ int fdisk_main(int argc, char **argv)
 
 	INIT_G();
 
+	opt_complementary = "b+:C+:H+:S+"; /* numeric params */
 	opt = getopt32(argv, "b:C:H:lS:u" USE_FEATURE_FDISK_BLKSIZE("s"),
-				&str_b, &str_C, &str_H, &str_S);
+				&sector_size, &user_cylinders, &user_heads, &user_sectors);
 	argc -= optind;
 	argv += optind;
 	if (opt & OPT_b) { // -b
@@ -2785,27 +2785,18 @@ int fdisk_main(int argc, char **argv)
 		   so cannot be combined with multiple disks,
 		   and the same goes for the C/H/S options.
 		*/
-		sector_size = xatoi_u(str_b);
-		if (sector_size != 512 && sector_size != 1024 &&
-			sector_size != 2048)
+		if (sector_size != 512 && sector_size != 1024
+		 && sector_size != 2048)
 			bb_show_usage();
 		sector_offset = 2;
 		user_set_sector_size = 1;
 	}
-	if (opt & OPT_C) user_cylinders = xatoi_u(str_C); // -C
-	if (opt & OPT_H) { // -H
-		user_heads = xatoi_u(str_H);
-		if (user_heads <= 0 || user_heads >= 256)
-			user_heads = 0;
-	}
-	//if (opt & OPT_l) // -l
-	if (opt & OPT_S) { // -S
-		user_sectors = xatoi_u(str_S);
-		if (user_sectors <= 0 || user_sectors >= 64)
-			user_sectors = 0;
-	}
-	if (opt & OPT_u) display_in_cyl_units = 0; // -u
-	//if (opt & OPT_s) // -s
+	if (user_heads <= 0 || user_heads >= 256)
+		user_heads = 0;
+	if (user_sectors <= 0 || user_sectors >= 64)
+		user_sectors = 0;
+	if (opt & OPT_u)
+		display_in_cyl_units = 0; // -u
 
 	if (user_set_sector_size && argc != 1)
 		printf("Warning: the -b (set sector size) option should"