Unify QFontEngine::getSfntTableData() behavior on all platforms

Being a most significant method in the font API,
getSfntTableData() must behave in exactly the same way on all platforms.
Briefly, it must return true if the table exists in the font,
despite the other params, and always stores the table data length
in 'length' param, thus reporting the amount of bytes actually
needed to store the table data in a buffer.

Change-Id: I7a15465020c1ea818ea46a05ea3b9b7e1cd60d14
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 4 insertions, 7 deletions

diff --git a/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm b/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
index 4fe78cb568..7ec59f552f 100644
--- a/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
+++ b/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
@@ -659,16 +659,13 @@ bool QCoreTextFontEngine::canRender(const QChar *string, int len)
 bool QCoreTextFontEngine::getSfntTableData(uint tag, uchar *buffer, uint *length) const
 {
     QCFType<CFDataRef> table = CTFontCopyTable(ctfont, tag, 0);
-    if (!table || !length)
+    if (!table)
         return false;
     CFIndex tableLength = CFDataGetLength(table);
-    int availableLength = *length;
-    *length = tableLength;
-    if (buffer) {
-        if (tableLength > availableLength)
-            return false;
+    if (buffer && int(*length) >= tableLength)
         CFDataGetBytes(table, CFRangeMake(0, tableLength), buffer);
-    }
+    *length = tableLength;
+    Q_ASSERT(int(*length) > 0);
     return true;
 }