Don't crash on malformed HTML in wxHTML font tag handler.

[wxWidgets.git] / src / common / imagbmp.cpp

diff --git a/src/common/imagbmp.cpp b/src/common/imagbmp.cpp
index 3e7a128d101005f7a473af6a8fe8b66475bc28b8..bc6f47c85841979209d41b42b59e2d9b4d6782a0 100644 (file)
--- a/src/common/imagbmp.cpp
+++ b/src/common/imagbmp.cpp
@@ -39,6 +39,16 @@
 // For memcpy
 #include <string.h>
 
+// ----------------------------------------------------------------------------
+// private functions
+// ----------------------------------------------------------------------------
+
+#if wxUSE_ICO_CUR
+
+static bool CanReadICOOrCUR(wxInputStream *stream, wxUint16 resourceType);
+
+#endif // wxUSE_ICO_CUR
+
 //-----------------------------------------------------------------------------
 // wxBMPHandler
 //-----------------------------------------------------------------------------
@@ -684,6 +694,14 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
 
     int linesize = ((width * bpp + 31) / 32) * 4;
 
+    // flag indicating if we have any not fully transparent alpha values: this
+    // is used to account for the bitmaps which use 32bpp format (normally
+    // meaning that they have alpha channel) but have only zeroes in it so that
+    // without this hack they appear fully transparent -- and as this is
+    // unlikely intentional, we consider that they don't have alpha at all in
+    // this case (see #10915)
+    bool hasValidAlpha = false;
+
     /* BMPs are stored upside down */
     for ( int line = (height - 1); line >= 0; line-- )
     {
@@ -895,6 +913,9 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
                 {
                     temp = (unsigned char)((aDword & amask) >> ashift);
                     alpha[line * width + column] = temp;
+
+                    if ( temp != wxALPHA_TRANSPARENT )
+                        hasValidAlpha = true;
                 }
                 column++;
             }
@@ -910,6 +931,13 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
 
     image->SetMask(false);
 
+    // check if we had any valid alpha values in this bitmap
+    if ( alpha && !hasValidAlpha )
+    {
+        // we didn't, so finally discard the alpha channel completely
+        image->ClearAlpha();
+    }
+
     const wxStreamError err = stream.GetLastError();
     return err == wxSTREAM_NO_ERROR || err == wxSTREAM_EOF;
 }
@@ -1406,12 +1434,8 @@ int wxICOHandler::DoGetImageCount(wxInputStream& stream)
 
 bool wxICOHandler::DoCanRead(wxInputStream& stream)
 {
-    unsigned char hdr[4];
-    if ( !stream.Read(hdr, WXSIZEOF(hdr)) )     // it's ok to modify the stream position here
-        return false;
+    return CanReadICOOrCUR(&stream, 1 /*for identifying an icon*/);
 
-    // hdr[2] is one for an icon and two for a cursor
-    return hdr[0] == '\0' && hdr[1] == '\0' && hdr[2] == '\1' && hdr[3] == '\0';
 }
 
 #endif // wxUSE_STREAMS
@@ -1427,12 +1451,7 @@ IMPLEMENT_DYNAMIC_CLASS(wxCURHandler, wxICOHandler)
 
 bool wxCURHandler::DoCanRead(wxInputStream& stream)
 {
-    unsigned char hdr[4];
-    if ( !stream.Read(hdr, WXSIZEOF(hdr)) )     // it's ok to modify the stream position here
-        return false;
-
-    // hdr[2] is one for an icon and two for a cursor
-    return hdr[0] == '\0' && hdr[1] == '\0' && hdr[2] == '\2' && hdr[3] == '\0';
+    return CanReadICOOrCUR(&stream, 2 /*for identifying a cursor*/);
 }
 
 #endif // wxUSE_STREAMS
@@ -1471,6 +1490,19 @@ int wxANIHandler::DoGetImageCount(wxInputStream& stream)
     return decoder.GetFrameCount();
 }
 
+static bool CanReadICOOrCUR(wxInputStream *stream, wxUint16 resourceType)
+{
+    ICONDIR iconDir;
+    if ( !stream->Read(&iconDir, sizeof(iconDir)) )     // it's ok to modify the stream position here
+    {
+        return false;
+    }
+
+    return !iconDir.idReserved // reserved, must be 0
+        && wxUINT16_SWAP_ON_BE(iconDir.idType) == resourceType // either 1 or 2
+        && iconDir.idCount; // must contain at least one image
+}
+
 #endif // wxUSE_STREAMS
 
 #endif // wxUSE_ICO_CUR