Fix failing transliteration spec

lib/ffi-icu/transliteration.rb

@@ -39,25 +39,23 @@ module ICU
         text_length = FFI::MemoryPointer.new :int32
 
 
+        retried = false
+
+        begin
+          # resets to original size on retry
           [limit, text_length].each do |ptr|
             ptr.put_int32(0, unicode_size)
           end
 
-        retried = false
-
-        begin
           Lib.check_error do |error|
             Lib.utrans_transUChars(@tr, buf, text_length, capacity, 0, limit, error)
           end
         rescue BufferOverflowError
           new_size = text_length.get_int32(0)
-          raise BufferOverflowError, "needed: #{new_size}" if retried
+          raise BufferOverflowError, "needed #{new_size}" if retried
 
           buf = buf.resized_to(new_size)
-          capacity = new_size
-
-          # reset to original size
-          text_length.put_int32 0, unicode_size
+          capacity = new_size + 1
 
           retried = true
           retry

test.c

@@ -29,11 +29,11 @@ int main (int argc, char const *argv[])
   }
 
   UChar from[256];
-  UChar buf[256];
+  UChar buf[6];
 
   int32_t text_length, limit;
 
-  u_uastrcpy(from, "Hello World");
+  u_uastrcpy(from, "abcde");
   u_strcpy(buf, from);
 
   limit = text_length = u_strlen(buf);