spark fix: negative num supp add

miscutils/spark.c

@@ -4,75 +4,78 @@
 #include <string.h>
 #include <math.h>
 
-long parse_long(const char *str) {
-	long val;
+int parse_long(const char *str, long *res) {
 	char *ptr;
 
-	val = strtol(str, &ptr, 0);
-	if (*ptr || val == 0)
-		return 1;
+	*res = strtol(str, &ptr, 0);
+	if (*ptr)
+		return 0;
 
-	return val;
+	return 1;
 }
 
-void print(long diff, long val, long min) {
+void print(long diff, char *str, long min) {
+	long val = 0;
+	if (!parse_long(str, &val))
+		return;
+
+	val -= min;
 	putchar('\xe2');
 	putchar('\x96');
-	putchar('\x82' + round(val - min - 1) / diff * 7);
+	putchar('\x81' + round(val) / diff * 7);
 }
 
 int main(int argc, char **argv) {
-	unsigned int r_flag = 0;
-	char ret = '\n';
-
-	int opt;
-	while ((opt = getopt(argc, argv, "nr")) != -1) {
-		switch (opt) {
-			case 'r':
-				r_flag = 1;
-				break;
-
-			case 'n':
-				ret = '\r';
-				break;
-
-			default:
-				printf("spark [val1 val2...]\n\t[-n Use \\r] [-r Reverse args]\n");
-				return 0;
-		}
-	}
-
-	argv += optind;
-	argc -= optind;
-
-	if (argc == 0) {
+	if (argc == 1) {
 		fprintf(stderr, "spark: missing operands\n");
 		return 1;
 	}
 
+	unsigned int r_flag = 0;
+	char ret = '\n';
+
 	long min = 0;
 	long max = 0;
 
 	for (int i = 1; i < argc; i++) {
-		long val = parse_long(argv[i]);
-		if (val > max)
-			max = val;
+		long val = 0;
+		if (parse_long(argv[i], &val)) {
+			if (val > max)
+				max = val;
 
-		else if (val < min)
-			min = val;
+			else if (val < min)
+				min = val;
+		}
+
+		else if (!strcmp(argv[i], "-r")) {
+			r_flag = 1;
+			argv++;
+			argc--;
+		}
+
+		else if (!strcmp(argv[i], "-n")) {
+			ret = '\r';
+			argv++;
+			argc--;
+		}
+
+		else {
+			printf("spark [num1 num2...]\n\t[-n Use \\r] [-r Reverse]\n");
+			return 0;
+		}
 	}
 
-	long diff = max - min - 1;
+	long diff = max - min;
 	if (diff < 1)
 		diff = 1;
 
 	if (r_flag)
-		for (int i = argc - 1; i >= 0; i--)
-			print(diff, parse_long(argv[i]), min);
+		for (int i = argc - 1; i >= 1; i--)
+			print(diff, argv[i], min);
 
 	else
-		for (int i = 0; i < argc; i++)
-			print(diff, parse_long(argv[i]), min);
+		for (int i = 1; i < argc; i++)
+			 print(diff, argv[i], min);
 
 	putchar(ret);
 	return 0;