gst/matroska/: fix signed integer reading/writing.

Original commit message from CVS:
2004-01-02  Ronald Bultje  <rbultje@ronald.bitfreak.net>

* gst/matroska/ebml-read.c: (gst_ebml_read_sint):
* gst/matroska/ebml-write.c: (gst_ebml_write_sint):
fix signed integer reading/writing.

1 files changed, 7 insertions, 1 deletions

diff --git a/gst/matroska/ebml-write.c b/gst/matroska/ebml-write.c
index 46cfd4a5..b6504867 100644
--- a/gst/matroska/ebml-write.c
+++ b/gst/matroska/ebml-write.c
@@ -391,7 +391,13 @@ gst_ebml_write_sint (GstEbmlWrite *ebml,
   guint size = gst_ebml_write_get_uint_size (unum);
 
   /* make unsigned */
-  unum = (num < 0 ? -num : num) + (1LLU << ((8 * size) - 1));
+  if (num >= 0) {
+    unum = num;
+  } else {
+    unum = 0x80 << (size - 1);
+    unum += num;
+    unum |= 0x80 << (size - 1);
+  }
 
   /* write */
   gst_ebml_write_element_id (buf, id);