check the return code of wxStream::Read() in wxImageHandler::DoCanRead()

and avoid reading uninitialized memory when it fails git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15601 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
2002-05-18 12:41:51 +00:00
parent baaae89f09
commit 79fa23744b
9 changed files with 55 additions and 33 deletions
--- a/src/common/imagjpeg.cpp
+++ b/src/common/imagjpeg.cpp
@@ -378,9 +378,11 @@ bool wxJPEGHandler::DoCanRead( wxInputStream& stream )
 {
    unsigned char hdr[2];

-    stream.Read(hdr, 2);
-    stream.SeekI(-2, wxFromCurrent);
-    return (hdr[0] == 0xFF && hdr[1] == 0xD8);
+    if ( !stream.Read(hdr, WXSIZEOF(hdr)) )
+        return FALSE;
+
+    stream.SeekI(-WXSIZEOF(hdr), wxFromCurrent);
+    return hdr[0] == 0xFF && hdr[1] == 0xD8;
 }

 #endif   // wxUSE_STREAMS