[t1cid] Improve cid_get_cid_from_glyph_index().

Update cid_get_cid_from_glyph_index() to
return an error and CID=0 in the case that
the specified glyph index points to an invalid
entry.

cidgload.h (cid_compute_fd_and_offsets):
Declare new helper function to set the
fd_select and 2 offsets to access the glyph
description data.

cidgload.c (cid_compute_fd_and_offsets):
Move the part loading fd_select and 2 offsets
from cid_load_glyph() to here.  If the loaded
parameters are broken, return the Invalid_Offset
error.  This function does not load the glyph
data, only fills these parameters.

(cid_load_glyph): Use new helper function in above.

cidriver.c (cid_get_cid_from_glyph_index):
Check whether the requested glyph index points
to a valid entry, by calling cid_compute_fd_and_offsets().
If it is valid, fill the cid by the glyph
index (=CID).  If it is invalid, return an
error and fill the cid by 0.

1 files changed, 15 insertions, 3 deletions

diff --git a/src/cid/cidriver.c b/src/cid/cidriver.c
index f7499237d..10cb8c1fd 100644
--- a/src/cid/cidriver.c
+++ b/src/cid/cidriver.c
@@ -150,11 +150,23 @@
                                 FT_UInt  *cid )
   {
     FT_Error  error = FT_Err_Ok;
-    FT_UNUSED( face );
 
 
-    if ( cid )
-      *cid = glyph_index; /* identity mapping */
+    /*
+     * Currently, FreeType does not support an incrementally-
+     * defined CID-keyed font that stores the glyph description
+     * data in /GlyphDirectory array or dictionary.
+     * Thus the font loaded by the incremental loading feature
+     * is not handled in here.
+     */
+    error = cid_compute_fd_and_offsets( face, glyph_index,
+                                        NULL, NULL, NULL );
+
+
+    if ( error )
+      *cid = 0;
+    else
+      *cid = glyph_index;
 
     return error;
   }