Fail blob creation if length overflows or is too large
Fail if blob start plus length overflows; or if blob length
is greater than 2GB. It takes a while for fonts to get to that
size. In the mean time, it protects against bugs like this:
http://www.icu-project.org/trac/ticket/11450
Also avoids some weird issues with 32bit vs 64bit systems
as we accept length as unsigned int. As such, a length of
-1 will cause overflow on 32bit machines, but happily
accepted on a 64bit machine. Avoid that.
diff --git a/test/api/test-blob.c b/test/api/test-blob.c
index bbb7e2e..f671331 100644
--- a/test/api/test-blob.c
+++ b/test/api/test-blob.c
@@ -53,6 +53,9 @@
g_assert (hb_blob_is_immutable (hb_blob_get_empty ()));
g_assert (hb_blob_get_empty () != NULL);
g_assert (hb_blob_get_empty () == hb_blob_create (NULL, 0, HB_MEMORY_MODE_READONLY, NULL, NULL));
+ g_assert (hb_blob_get_empty () == hb_blob_create ("asdf", 0, HB_MEMORY_MODE_READONLY, NULL, NULL));
+ g_assert (hb_blob_get_empty () == hb_blob_create (NULL, -1, HB_MEMORY_MODE_READONLY, NULL, NULL));
+ g_assert (hb_blob_get_empty () == hb_blob_create ("asdfg", -1, HB_MEMORY_MODE_READONLY, NULL, NULL));
blob = hb_blob_get_empty ();
g_assert (blob == hb_blob_get_empty ());
