btrfs-progs: cleanup and comment parse_range

Simplify a check and unindent some code.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/cmds-balance.c b/cmds-balance.c
index b02e40d..c1219be 100644 (file)
--- a/cmds-balance.c
+++ b/cmds-balance.c
@@ -88,43 +88,54 @@ static int parse_u64(const char *str, u64 *result)
        return 0;
 }
 
+/*
+ * Parse range that's missing some part that can be implicit:
+ * a..b        - exact range, a can be equal to b
+ * a.. - implicitly unbounded maximum (end == (u64)-1)
+ * ..b - implicitly starting at 0
+ * a   - invalid; unclear semantics, use parse_u64 instead
+ *
+ * Returned values are u64, value validation and interpretation should be done
+ * by the caller.
+ */
 static int parse_range(const char *range, u64 *start, u64 *end)
 {
        char *dots;
+       const char *rest;
+       int skipped = 0;
 
        dots = strstr(range, "..");
-       if (dots) {
-               const char *rest = dots + 2;
-               int skipped = 0;
-
-               *dots = 0;
+       if (!dots)
+               return 1;
 
-               if (!*rest) {
-                       *end = (u64)-1;
-                       skipped++;
-               } else {
-                       if (parse_u64(rest, end))
-                               return 1;
-               }
-               if (dots == range) {
-                       *start = 0;
-                       skipped++;
-               } else {
-                       if (parse_u64(range, start))
-                               return 1;
-               }
+       rest = dots + 2;
+       *dots = 0;
 
-               if (*start >= *end) {
-                       fprintf(stderr, "Range %llu..%llu doesn't make "
-                               "sense\n", (unsigned long long)*start,
-                               (unsigned long long)*end);
+       if (!*rest) {
+               *end = (u64)-1;
+               skipped++;
+       } else {
+               if (parse_u64(rest, end))
                        return 1;
-               }
+       }
+       if (dots == range) {
+               *start = 0;
+               skipped++;
+       } else {
+               if (parse_u64(range, start))
+                       return 1;
+       }
 
-               if (skipped <= 1)
-                       return 0;
+       if (*start >= *end) {
+               fprintf(stderr, "Range %llu..%llu doesn't make "
+                       "sense\n", (unsigned long long)*start,
+                       (unsigned long long)*end);
+               return 1;
        }
 
+       if (skipped <= 1)
+               return 0;
+
        return 1;
 }