bug: string range length signed/unsigned.

* lib.c (length_str_range): On platforms where wchar_t is
unsigned, we calculate bogus values for reversed ranges.
On Android, gcc warns about the code, and the recently
added tests fail.  Let's cast the characters to long before
doing the subtraction, which is the argument type of labs.

1 files changed, 2 insertions, 1 deletions

diff --git a/lib.c b/lib.c
index 11cf3340..512810f2 100644
--- a/lib.c
+++ b/lib.c
@@ -564,7 +564,8 @@ static val length_str_range(val from, val to)
     cnum i;
 
     for (i = 0; fs[i]; i++)
-      out = mul(out, num(labs(ts[i] - fs[i]) + 1));
+      out = mul(out, num(labs(convert(long, ts[i]) -
+                              convert(long, fs[i])) + 1));
 
     gc_hint(from);
     gc_hint(to);