[hackers] [libzahl] Why zbits returns 1 for 0 || Mattias Andrée

[git]

commit fe15c7e5b115cae4717f5481e7962cf376066387
Author:     Mattias Andrée <maand...@kth.se>
AuthorDate: Wed Mar 2 08:57:46 2016 +0100
Commit:     Mattias Andrée <maand...@kth.se>
CommitDate: Wed Mar 2 08:57:50 2016 +0100

    Why zbits returns 1 for 0
    
    Signed-off-by: Mattias Andrée <maand...@kth.se>

diff --git a/man/zbits.3 b/man/zbits.3
index 3dea6d9..191a87c 100644
--- a/man/zbits.3
+++ b/man/zbits.3
@@ -25,6 +25,14 @@ absolute value of
 \(em or 1 if
 .I a
 is zero.
+.SH RATIONALE
+.B zbits
+returns 1 rather than 0 if
+.B a
+is zero, this is to avoid off-by-one errors
+and it is the number of digits requires to
+write the number in binary. You will see this
+in corresponding functions in other libraries.
 .SH SEE ALSO
 .BR zlsb (3),
 .BR zzero (3)
diff --git a/src/zbits.c b/src/zbits.c
index 8ada62f..f0c15c9 100644
--- a/src/zbits.c
+++ b/src/zbits.c
@@ -7,9 +7,8 @@ zbits(z_t a)
 {
        size_t i;
        zahl_char_t x;
-       if (zzero(a)) {
-               return 1;
-       }
+       if (zzero(a))
+               return 1; /* Deliver us from evil! */
        for (i = a->used - 1;; i--) {
                x = a->chars[i];
                if (x) {