don't crash if one of GetAllCommands() parameters is NULL (coverity checker CID 11)

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

diff --git a/src/common/gifdecod.cpp b/src/common/gifdecod.cpp
index 011d8cf3ad06e2d385bbc767bb450ed19f04eaaf..8fda5f8ae137b2588d566077a4547b08500aac49 100644 (file)
--- a/src/common/gifdecod.cpp
+++ b/src/common/gifdecod.cpp
@@ -8,10 +8,6 @@
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
-#ifdef __GNUG__
-#pragma implementation "gifdecod.h"
-#endif
-
 // For compilers that support precompilation, includes "wx.h".
 #include "wx/wxprec.h"
 
@@ -21,6 +17,7 @@
 
 #ifndef WX_PRECOMP
 #  include "wx/defs.h"
+#  include "wx/palette.h"
 #endif
 
 #if wxUSE_STREAMS && wxUSE_GIF
@@ -115,7 +112,7 @@ bool wxGIFDecoder::ConvertToImage(wxImage *image) const
     image->Create(GetWidth(), GetHeight());
 
     if (!image->Ok())
-        return FALSE;
+        return false;
 
     pal = GetPalette();
     src = GetData();
@@ -142,24 +139,21 @@ bool wxGIFDecoder::ConvertToImage(wxImage *image) const
         image->SetMaskColour(255, 0, 255);
     }
     else
-        image->SetMask(FALSE);
+        image->SetMask(false);
 
 #if wxUSE_PALETTE
-    if (pal)
-    {
-        unsigned char r[256];
-        unsigned char g[256];
-        unsigned char b[256];
+    unsigned char r[256];
+    unsigned char g[256];
+    unsigned char b[256];
 
-        for (i = 0; i < 256; i++)
-        {
-            r[i] = pal[3*i + 0];
-            g[i] = pal[3*i + 1];
-            b[i] = pal[3*i + 2];
-        }
-
-        image->SetPalette(wxPalette(256, r, g, b));
+    for (i = 0; i < 256; i++)
+    {
+        r[i] = pal[3*i + 0];
+        g[i] = pal[3*i + 1];
+        b[i] = pal[3*i + 2];
     }
+
+    image->SetPalette(wxPalette(256, r, g, b));
 #endif // wxUSE_PALETTE
 
     /* copy image data */
@@ -170,7 +164,7 @@ bool wxGIFDecoder::ConvertToImage(wxImage *image) const
         *(dst++) = pal[3 * (*src) + 2];
     }
 
-    return TRUE;
+    return true;
 }
 
 
@@ -207,27 +201,27 @@ bool wxGIFDecoder::IsAnimation() const          { return (m_nimages > 1); }
 bool wxGIFDecoder::GoFirstFrame()
 {
     if (!IsAnimation())
-        return FALSE;
+        return false;
 
     m_image = 1;
     m_pimage = m_pfirst;
-    return TRUE;
+    return true;
 }
 
 bool wxGIFDecoder::GoLastFrame()
 {
     if (!IsAnimation())
-        return FALSE;
+        return false;
 
     m_image = m_nimages;
     m_pimage = m_plast;
-    return TRUE;
+    return true;
 }
 
 bool wxGIFDecoder::GoNextFrame(bool cyclic)
 {
     if (!IsAnimation())
-        return FALSE;
+        return false;
 
     if ((m_image < m_nimages) || (cyclic))
     {
@@ -240,16 +234,16 @@ bool wxGIFDecoder::GoNextFrame(bool cyclic)
             m_pimage = m_pfirst;
         }
 
-        return TRUE;
+        return true;
     }
     else
-        return FALSE;
+        return false;
 }
 
 bool wxGIFDecoder::GoPrevFrame(bool cyclic)
 {
     if (!IsAnimation())
-        return FALSE;
+        return false;
 
     if ((m_image > 1) || (cyclic))
     {
@@ -262,30 +256,32 @@ bool wxGIFDecoder::GoPrevFrame(bool cyclic)
             m_pimage = m_plast;
         }
 
-        return TRUE;
+        return true;
     }
     else
-        return FALSE;
+        return false;
 }
 
 bool wxGIFDecoder::GoFrame(int which)
 {
-    int i;
-
     if (!IsAnimation())
-        return FALSE;
+        return false;
 
     if ((which >= 1) && (which <= m_nimages))
     {
+        m_image = 1;
         m_pimage = m_pfirst;
 
-        for (i = 1; i < which; i++)
+        while (m_image < which)
+        {
+            m_image++;
             m_pimage = m_pimage->next;
+        }
 
-        return TRUE;
+        return true;
     }
     else
-        return FALSE;
+        return false;
 }
 
 
@@ -506,7 +502,7 @@ int wxGIFDecoder::dgif(GIFImage *img, int interl, int bits)
                     /* loop until a valid y coordinate has been
                     found, Or if the maximum number of passes has
                     been reached, exit the loop, and stop image
-                    decoding (At this point the image is succesfully
+                    decoding (At this point the image is successfully
                     decoded).
                     If we don't loop, but merely set y to some other
                     value, that new value might still be invalid depending
@@ -611,16 +607,18 @@ as an End of Information itself)
 
 
 // CanRead:
-//  Returns TRUE if the file looks like a valid GIF, FALSE otherwise.
+//  Returns true if the file looks like a valid GIF, false otherwise.
 //
 bool wxGIFDecoder::CanRead()
 {
     unsigned char buf[3];
 
-    m_f->Read(buf, 3);
-    m_f->SeekI(-3, wxFromCurrent);
+    if ( !m_f->Read(buf, WXSIZEOF(buf)) )
+        return false;
+
+    m_f->SeekI(-(wxFileOffset)WXSIZEOF(buf), wxFromCurrent);
 
-    return (memcmp(buf, "GIF", 3) == 0);
+    return memcmp(buf, "GIF", WXSIZEOF(buf)) == 0;
 }
 
 
@@ -660,7 +658,7 @@ int wxGIFDecoder::ReadGIF()
 
     if (memcmp(buf + 3, "89a", 3) < 0)
     {
-        m_anim = FALSE;
+        m_anim = false;
     }
 
     /* read logical screen descriptor block (LSDB) */
@@ -674,6 +672,11 @@ int wxGIFDecoder::ReadGIF()
     m_screenw = buf[0] + 256 * buf[1];
     m_screenh = buf[2] + 256 * buf[3];
 
+    if ((m_screenw == 0) || (m_screenh == 0))
+    {
+        return wxGIF_INVFORMAT;
+    }
+
     /* load global color map if available */
     if ((buf[4] & 0x80) == 0x80)
     {
@@ -698,9 +701,9 @@ int wxGIFDecoder::ReadGIF()
     pprev = NULL;
     pimg  = NULL;
 
-    bool done = FALSE;
+    bool done = false;
 
-    while(!done)
+    while (!done)
     {
         type = (unsigned char)m_f->GetC();
 
@@ -724,7 +727,7 @@ int wxGIFDecoder::ReadGIF()
         /* end of data? */
         if (type == 0x3B)
         {
-            done = TRUE;
+            done = true;
         }
         else
         /* extension block? */
@@ -749,7 +752,7 @@ int wxGIFDecoder::ReadGIF()
                     transparent = buf[4];
 
                 /* read disposal method */
-                disposal = (buf[1] & 0x1C) - 1;
+                disposal = ((buf[1] & 0x1C) >> 2) - 1;
             }
             else
             /* other extension, skip */
@@ -759,7 +762,7 @@ int wxGIFDecoder::ReadGIF()
                     m_f->SeekI(i, wxFromCurrent);
                     if (m_f->Eof())
                     {
-                        done = TRUE;
+                        done = true;
                         break;
                     }
                 }
@@ -796,7 +799,7 @@ int wxGIFDecoder::ReadGIF()
             pimg->w = buf[4] + 256 * buf[5];
             pimg->h = buf[6] + 256 * buf[7];
 
-            if (pimg->w == 0 || pimg->h == 0)
+            if ((pimg->w == 0) || (pimg->w > m_screenw) || (pimg->h == 0) || (pimg->h > m_screenh))
             {
                 Destroy();
                 return wxGIF_INVFORMAT;
@@ -842,6 +845,11 @@ int wxGIFDecoder::ReadGIF()
 
             /* get initial code size from first byte in raster data */
             bits = (unsigned char)m_f->GetC();
+            if (bits == 0)
+            {
+                Destroy();
+                return wxGIF_INVFORMAT;
+            }
 
             /* decode image */
             int result = dgif(pimg, interl, bits);
@@ -854,11 +862,11 @@ int wxGIFDecoder::ReadGIF()
 
             /* if this is not an animated GIF, exit after first image */
             if (!m_anim)
-                done = TRUE;
+                done = true;
         }
     }
 
-    if (m_nimages == 0)
+    if (m_nimages <= 0)
     {
         Destroy();
         return wxGIF_INVFORMAT;
@@ -903,8 +911,8 @@ int wxGIFDecoder::ReadGIF()
             if ((buf[8] & 0x80) == 0x80)
             {
                 ncolors = 2 << (buf[8] & 0x07);
-                off_t pos = m_f->TellI();
-                off_t numBytes = 3 * ncolors;
+                wxFileOffset pos = m_f->TellI();
+                wxFileOffset numBytes = 3 * ncolors;
                 m_f->SeekI(numBytes, wxFromCurrent);
                 if (m_f->TellI() != (pos + numBytes))
                 {