Fix for always failing assert in GetValue. Save the same value that

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

diff --git a/src/common/gifdecod.cpp b/src/common/gifdecod.cpp
index 68be026a7bb76f0025323b2ce6df31fdd70589d9..0b53e9c627d29b16323fd77c1123d6549d5df699 100644 (file)
--- a/src/common/gifdecod.cpp
+++ b/src/common/gifdecod.cpp
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////

-// Name:        gifdecod.cpp
+// Name:        src/common/gifdecod.cpp

 // Purpose:     wxGIFDecoder, GIF reader for wxImage and wxAnimation
 // Author:      Guillermo Rodriguez Garcia <guille@iies.es>
 // Version:     3.04
 // Purpose:     wxGIFDecoder, GIF reader for wxImage and wxAnimation
 // Author:      Guillermo Rodriguez Garcia <guille@iies.es>
 // Version:     3.04


@@ -12,21 +12,48 @@
 #include "wx/wxprec.h"
 
 #ifdef __BORLANDC__
 #include "wx/wxprec.h"
 
 #ifdef __BORLANDC__

-#  pragma hdrstop
+    #pragma hdrstop

 #endif
 
 #endif
 

+#if wxUSE_STREAMS && wxUSE_GIF
+

 #ifndef WX_PRECOMP
 #ifndef WX_PRECOMP

-#  include "wx/defs.h"
-#  include "wx/palette.h"
+    #include "wx/palette.h"

 #endif
 
 #endif
 

-#if wxUSE_STREAMS && wxUSE_GIF
-

 #include <stdlib.h>
 #include <string.h>
 #include "wx/gifdecod.h"
 
 
 #include <stdlib.h>
 #include <string.h>
 #include "wx/gifdecod.h"
 
 

+
+//---------------------------------------------------------------------------
+// GIFImage
+//---------------------------------------------------------------------------
+
+// internal class for storing GIF image data
+class GIFImage
+{
+public:
+    // def ctor
+    GIFImage();
+
+    unsigned int w;                 /* width */
+    unsigned int h;                 /* height */
+    unsigned int left;              /* x coord (in logical screen) */
+    unsigned int top;               /* y coord (in logical screen) */
+    int transparent;                /* transparent color index (-1 = none) */
+    wxAnimationDisposal disposal;   /* disposal method */
+    long delay;                     /* delay in ms (-1 = unused) */
+    unsigned char *p;               /* bitmap */
+    unsigned char *pal;             /* palette */
+    unsigned int ncolours;          /* number of colours */
+
+    DECLARE_NO_COPY_CLASS(GIFImage)
+};
+
+
+

 //---------------------------------------------------------------------------
 // GIFImage constructor
 //---------------------------------------------------------------------------
 //---------------------------------------------------------------------------
 // GIFImage constructor
 //---------------------------------------------------------------------------


@@ -37,32 +64,19 @@ GIFImage::GIFImage()
     left = 0;
     top = 0;
     transparent = 0;
     left = 0;
     top = 0;
     transparent = 0;

-    disposal = 0;
+    disposal = wxANIM_DONOTREMOVE;

     delay = -1;
     p = (unsigned char *) NULL;
     pal = (unsigned char *) NULL;
     delay = -1;
     p = (unsigned char *) NULL;
     pal = (unsigned char *) NULL;

-    next = (GIFImage *) NULL;
-    prev = (GIFImage *) NULL;
+    ncolours = 0;

 }
 
 //---------------------------------------------------------------------------
 // wxGIFDecoder constructor and destructor
 //---------------------------------------------------------------------------
 
 }
 
 //---------------------------------------------------------------------------
 // wxGIFDecoder constructor and destructor
 //---------------------------------------------------------------------------
 

-wxGIFDecoder::wxGIFDecoder(wxInputStream *s, bool anim)
+wxGIFDecoder::wxGIFDecoder()

 {
 {

-    m_f    = s;
-    m_anim = anim;
-
-    m_background = -1;
-    m_screenw = 0;
-    m_screenh = 0;
-
-    m_pimage  = NULL;
-    m_pfirst  = NULL;
-    m_plast   = NULL;
-    m_image   = 0;
-    m_nimages = 0;

 }
 
 wxGIFDecoder::~wxGIFDecoder()
 }
 
 wxGIFDecoder::~wxGIFDecoder()


@@ -72,24 +86,17 @@ wxGIFDecoder::~wxGIFDecoder()
 
 void wxGIFDecoder::Destroy()
 {
 
 void wxGIFDecoder::Destroy()
 {

-    GIFImage *pimg, *paux;
-
-    pimg = m_pfirst;
-
-    while (pimg != NULL)
+    wxASSERT(m_nFrames==m_frames.GetCount());
+    for (size_t i=0; i<m_nFrames; i++)

     {
     {

-        paux = pimg->next;
-        free(pimg->p);
-        free(pimg->pal);
-        delete pimg;
-        pimg = paux;
+        GIFImage *f = (GIFImage*)m_frames[i];
+        free(f->p);
+        free(f->pal);
+        delete f;

     }
 
     }
 

-    m_pimage  = NULL;
-    m_pfirst  = NULL;
-    m_plast   = NULL;
-    m_image   = 0;
-    m_nimages = 0;
+    m_frames.Clear();
+    m_nFrames = 0;

 }
 
 
 }
 
 


@@ -99,7 +106,7 @@ void wxGIFDecoder::Destroy()
 
 // This function was designed by Vaclav Slavik
 
 
 // This function was designed by Vaclav Slavik
 

-bool wxGIFDecoder::ConvertToImage(wxImage *image) const
+bool wxGIFDecoder::ConvertToImage(size_t frame, wxImage *image) const

 {
     unsigned char *src, *dst, *pal;
     unsigned long i;
 {
     unsigned char *src, *dst, *pal;
     unsigned long i;


@@ -109,20 +116,21 @@ bool wxGIFDecoder::ConvertToImage(wxImage *image) const
     image->Destroy();
 
     /* create the image */
     image->Destroy();
 
     /* create the image */

-    image->Create(GetWidth(), GetHeight());
+    wxSize sz = GetFrameSize(frame);
+    image->Create(sz.GetWidth(), sz.GetHeight());

 
     if (!image->Ok())
         return false;
 
 
     if (!image->Ok())
         return false;
 

-    pal = GetPalette();
-    src = GetData();
+    pal = GetPalette(frame);
+    src = GetData(frame);

     dst = image->GetData();
     dst = image->GetData();

-    transparent = GetTransparentColour();
+    transparent = GetTransparentColourIndex(frame);

 
     /* set transparent colour mask */
     if (transparent != -1)
     {
 
     /* set transparent colour mask */
     if (transparent != -1)
     {

-        for (i = 0; i < 256; i++)
+        for (i = 0; i < GetNcolours(frame); i++)

         {
             if ((pal[3 * i + 0] == 255) &&
                 (pal[3 * i + 1] == 0) &&
         {
             if ((pal[3 * i + 0] == 255) &&
                 (pal[3 * i + 1] == 0) &&


@@ -142,25 +150,23 @@ bool wxGIFDecoder::ConvertToImage(wxImage *image) const
         image->SetMask(false);
 
 #if wxUSE_PALETTE
         image->SetMask(false);
 
 #if wxUSE_PALETTE

-    if (pal)
-    {
-        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];
-        }
+    unsigned char r[256];
+    unsigned char g[256];
+    unsigned char b[256];

 
 

-        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(GetNcolours(frame), r, g, b));

 #endif // wxUSE_PALETTE
 
     /* copy image data */
 #endif // wxUSE_PALETTE
 
     /* copy image data */

-    for (i = 0; i < (GetWidth() * GetHeight()); i++, src++)
+    unsigned long npixel = sz.GetWidth() * sz.GetHeight();
+    for (i = 0; i < npixel; i++, src++)

     {
         *(dst++) = pal[3 * (*src) + 0];
         *(dst++) = pal[3 * (*src) + 1];
     {
         *(dst++) = pal[3 * (*src) + 0];
         *(dst++) = pal[3 * (*src) + 1];


@@ -175,117 +181,48 @@ bool wxGIFDecoder::ConvertToImage(wxImage *image) const
 // Data accessors
 //---------------------------------------------------------------------------
 
 // Data accessors
 //---------------------------------------------------------------------------
 

-// Get data for current frame
-
-int wxGIFDecoder::GetFrameIndex() const         { return m_image; }
-unsigned char* wxGIFDecoder::GetData() const    { return (m_pimage->p); }
-unsigned char* wxGIFDecoder::GetPalette() const { return (m_pimage->pal); }
-unsigned int wxGIFDecoder::GetWidth() const     { return (m_pimage->w); }
-unsigned int wxGIFDecoder::GetHeight() const    { return (m_pimage->h); }
-unsigned int wxGIFDecoder::GetTop() const       { return (m_pimage->top); }
-unsigned int wxGIFDecoder::GetLeft() const      { return (m_pimage->left); }
-int wxGIFDecoder::GetTransparentColour() const  { return (m_pimage->transparent); }
-int wxGIFDecoder::GetDisposalMethod() const     { return (m_pimage->disposal); }
-long wxGIFDecoder::GetDelay() const             { return (m_pimage->delay); }
-
-// Get global data
+#define GetFrame(n)     ((GIFImage*)m_frames[n])

 
 

-unsigned int wxGIFDecoder::GetLogicalScreenWidth() const    { return m_screenw; }
-unsigned int wxGIFDecoder::GetLogicalScreenHeight() const   { return m_screenh; }
-int wxGIFDecoder::GetBackgroundColour() const   { return m_background; }
-int wxGIFDecoder::GetNumberOfFrames() const     { return m_nimages; }
-bool wxGIFDecoder::IsAnimation() const          { return (m_nimages > 1); }

 
 

+// Get data for current frame

 
 

-//---------------------------------------------------------------------------
-// Functions to move through the animation
-//---------------------------------------------------------------------------
-
-bool wxGIFDecoder::GoFirstFrame()
+wxSize wxGIFDecoder::GetFrameSize(size_t frame) const 

 {
 {

-    if (!IsAnimation())
-        return false;
-
-    m_image = 1;
-    m_pimage = m_pfirst;
-    return true;
+    return wxSize(GetFrame(frame)->w, GetFrame(frame)->h);

 }
 
 }
 

-bool wxGIFDecoder::GoLastFrame()
+wxPoint wxGIFDecoder::GetFramePosition(size_t frame) const

 {
 {

-    if (!IsAnimation())
-        return false;
-
-    m_image = m_nimages;
-    m_pimage = m_plast;
-    return true;
+    return wxPoint(GetFrame(frame)->left, GetFrame(frame)->top);

 }
 
 }
 

-bool wxGIFDecoder::GoNextFrame(bool cyclic)
+wxAnimationDisposal wxGIFDecoder::GetDisposalMethod(size_t frame) const

 {
 {

-    if (!IsAnimation())
-        return false;
-
-    if ((m_image < m_nimages) || (cyclic))
-    {
-        m_pimage = m_pimage->next;
-        m_image++;
-
-        if (!m_pimage)
-        {
-            m_image = 1;
-            m_pimage = m_pfirst;
-        }
-
-        return true;
-    }
-    else
-        return false;
+    return GetFrame(frame)->disposal;

 }
 
 }
 

-bool wxGIFDecoder::GoPrevFrame(bool cyclic)
+long wxGIFDecoder::GetDelay(size_t frame) const

 {
 {

-    if (!IsAnimation())
-        return false;
-
-    if ((m_image > 1) || (cyclic))
-    {
-        m_pimage = m_pimage->prev;
-        m_image--;
-
-        if (!m_pimage)
-        {
-            m_image = m_nimages;
-            m_pimage = m_plast;
-        }
-
-        return true;
-    }
-    else
-        return false;
+    return GetFrame(frame)->delay;

 }
 
 }
 

-bool wxGIFDecoder::GoFrame(int which)
+wxColour wxGIFDecoder::GetTransparentColour(size_t frame) const

 {
 {

-    if (!IsAnimation())
-        return false;
+    unsigned char *pal = GetFrame(frame)->pal;
+    int n = GetFrame(frame)->transparent;
+    if (n == -1)
+        return wxNullColour;
+
+    return wxColour(pal[n*3 + 0],
+                    pal[n*3 + 1],
+                    pal[n*3 + 2]);
+}

 
 

-    if ((which >= 1) && (which <= m_nimages))
-    {
-        m_image = 1;
-        m_pimage = m_pfirst;
+unsigned char* wxGIFDecoder::GetData(size_t frame) const    { return (GetFrame(frame)->p); }
+unsigned char* wxGIFDecoder::GetPalette(size_t frame) const { return (GetFrame(frame)->pal); }
+unsigned int wxGIFDecoder::GetNcolours(size_t frame) const  { return (GetFrame(frame)->ncolours); }
+int wxGIFDecoder::GetTransparentColourIndex(size_t frame) const  { return (GetFrame(frame)->transparent); }

 
 

-        while (m_image < which)
-        {
-            m_image++;
-            m_pimage = m_pimage->next;
-        }
-
-        return true;
-    }
-    else
-        return false;
-}

 
 
 //---------------------------------------------------------------------------
 
 
 //---------------------------------------------------------------------------


@@ -295,12 +232,11 @@ bool wxGIFDecoder::GoFrame(int which)
 // getcode:
 //  Reads the next code from the file stream, with size 'bits'
 //
 // getcode:
 //  Reads the next code from the file stream, with size 'bits'
 //

-int wxGIFDecoder::getcode(int bits, int ab_fin)
+int wxGIFDecoder::getcode(wxInputStream& stream, int bits, int ab_fin)

 {
     unsigned int mask;          /* bit mask */
     unsigned int code;          /* code (result) */
 
 {
     unsigned int mask;          /* bit mask */
     unsigned int code;          /* code (result) */
 

-

     /* get remaining bits from last byte read */
     mask = (1 << bits) - 1;
     code = (m_lastbyte >> (8 - m_restbits)) & mask;
     /* get remaining bits from last byte read */
     mask = (1 << bits) - 1;
     code = (m_lastbyte >> (8 - m_restbits)) & mask;


@@ -311,7 +247,7 @@ int wxGIFDecoder::getcode(int bits, int ab_fin)
         /* if no bytes left in this block, read the next block */
         if (m_restbyte == 0)
         {
         /* if no bytes left in this block, read the next block */
         if (m_restbyte == 0)
         {

-            m_restbyte = (unsigned char)m_f->GetC();
+            m_restbyte = (unsigned char)stream.GetC();

 
             /* Some encoders are a bit broken: instead of issuing
              * an end-of-image symbol (ab_fin) they come up with
 
             /* Some encoders are a bit broken: instead of issuing
              * an end-of-image symbol (ab_fin) they come up with


@@ -325,8 +261,8 @@ int wxGIFDecoder::getcode(int bits, int ab_fin)
             }
 
             /* prefetch data */
             }
 
             /* prefetch data */

-            m_f->Read((void *) m_buffer, m_restbyte);
-            if (m_f->LastRead() != m_restbyte)
+            stream.Read((void *) m_buffer, m_restbyte);
+            if (stream.LastRead() != m_restbyte)

             {
                 code = ab_fin;
                 return code;
             {
                 code = ab_fin;
                 return code;


@@ -356,7 +292,7 @@ int wxGIFDecoder::getcode(int bits, int ab_fin)
 //  is 'bits'. Supports interlaced images (interl == 1).
 //  Returns wxGIF_OK (== 0) on success, or an error code if something
 // fails (see header file for details)
 //  is 'bits'. Supports interlaced images (interl == 1).
 //  Returns wxGIF_OK (== 0) on success, or an error code if something
 // fails (see header file for details)

-int wxGIFDecoder::dgif(GIFImage *img, int interl, int bits)
+wxGIFErrorCode wxGIFDecoder::dgif(wxInputStream& stream, GIFImage *img, int interl, int bits)

 {
     static const int allocSize = 4096 + 1;
     int *ab_prefix = new int[allocSize]; /* alphabet (prefixes) */
 {
     static const int allocSize = 4096 + 1;
     int *ab_prefix = new int[allocSize]; /* alphabet (prefixes) */


@@ -412,7 +348,7 @@ int wxGIFDecoder::dgif(GIFImage *img, int interl, int bits)
     do
     {
         /* get next code */
     do
     {
         /* get next code */

-        readcode = code = getcode(ab_bits, ab_fin);
+        readcode = code = getcode(stream, ab_bits, ab_fin);

 
         /* end of image? */
         if (code == ab_fin) break;
 
         /* end of image? */
         if (code == ab_fin) break;


@@ -470,6 +406,25 @@ int wxGIFDecoder::dgif(GIFImage *img, int interl, int bits)
         /* make new entry in alphabet (only if NOT just cleared) */
         if (lastcode != -1)
         {
         /* make new entry in alphabet (only if NOT just cleared) */
         if (lastcode != -1)
         {

+            // Normally, after the alphabet is full and can't grow any
+            // further (ab_free == 4096), encoder should (must?) emit CLEAR
+            // to reset it. This checks whether we really got it, otherwise
+            // the GIF is damaged.
+            if (ab_free > ab_max)
+            {
+                delete[] ab_prefix;
+                delete[] ab_tail;
+                delete[] stack;
+                return wxGIF_INVFORMAT;
+            }
+
+            // This assert seems unnecessary since the condition above
+            // eliminates the only case in which it went false. But I really
+            // don't like being forced to ask "Who in .text could have
+            // written there?!" And I wouldn't have been forced to ask if
+            // this line had already been here.
+            wxASSERT(ab_free < allocSize);
+

             ab_prefix[ab_free] = lastcode;
             ab_tail[ab_free]   = code;
             ab_free++;
             ab_prefix[ab_free] = lastcode;
             ab_tail[ab_free]   = code;
             ab_free++;


@@ -612,20 +567,20 @@ as an End of Information itself)
 // CanRead:
 //  Returns true if the file looks like a valid GIF, false otherwise.
 //
 // CanRead:
 //  Returns true if the file looks like a valid GIF, false otherwise.
 //

-bool wxGIFDecoder::CanRead()
+bool wxGIFDecoder::CanRead(wxInputStream &stream) const

 {
     unsigned char buf[3];
 
 {
     unsigned char buf[3];
 

-    if ( !m_f->Read(buf, WXSIZEOF(buf)) )
+    if ( !stream.Read(buf, WXSIZEOF(buf)) )

         return false;
 
         return false;
 

-    m_f->SeekI(-(wxFileOffset)WXSIZEOF(buf), wxFromCurrent);
+    stream.SeekI(-(wxFileOffset)WXSIZEOF(buf), wxFromCurrent);

 
     return memcmp(buf, "GIF", WXSIZEOF(buf)) == 0;
 }
 
 
 
     return memcmp(buf, "GIF", WXSIZEOF(buf)) == 0;
 }
 
 

-// ReadGIF:
+// LoadGIF:

 //  Reads and decodes one or more GIF images, depending on whether
 //  animated GIF support is enabled. Can read GIFs with any bit
 //  size (color depth), but the output images are always expanded
 //  Reads and decodes one or more GIF images, depending on whether
 //  animated GIF support is enabled. Can read GIFs with any bit
 //  size (color depth), but the output images are always expanded


@@ -634,49 +589,48 @@ bool wxGIFDecoder::CanRead()
 //  (== 0) on success, or an error code if something fails (see
 //  header file for details)
 //
 //  (== 0) on success, or an error code if something fails (see
 //  header file for details)
 //

-int wxGIFDecoder::ReadGIF()
+wxGIFErrorCode wxGIFDecoder::LoadGIF(wxInputStream& stream)

 {
 {

-    unsigned int ncolors;
-    int           bits, interl, transparent, disposal, i;
+    unsigned int  global_ncolors = 0;
+    int           bits, interl, transparent, i;
+    wxAnimationDisposal disposal;

     long          size;
     long          delay;
     unsigned char type = 0;
     unsigned char pal[768];
     unsigned char buf[16];
     long          size;
     long          delay;
     unsigned char type = 0;
     unsigned char pal[768];
     unsigned char buf[16];

-    GIFImage      **ppimg;
-    GIFImage      *pimg, *pprev;
+    bool anim = true;

 
     /* check GIF signature */
 
     /* check GIF signature */

-    if (!CanRead())
+    if (!CanRead(stream))

         return wxGIF_INVFORMAT;
 
     /* check for animated GIF support (ver. >= 89a) */
 
     static const size_t headerSize = (3 + 3);
         return wxGIF_INVFORMAT;
 
     /* check for animated GIF support (ver. >= 89a) */
 
     static const size_t headerSize = (3 + 3);

-    m_f->Read(buf, headerSize);
-    if (m_f->LastRead() != headerSize)
+    stream.Read(buf, headerSize);
+    if (stream.LastRead() != headerSize)

     {
         return wxGIF_INVFORMAT;
     }
 
     if (memcmp(buf + 3, "89a", 3) < 0)
     {
     {
         return wxGIF_INVFORMAT;
     }
 
     if (memcmp(buf + 3, "89a", 3) < 0)
     {

-        m_anim = false;
+        anim = false;

     }
 
     /* read logical screen descriptor block (LSDB) */
     static const size_t lsdbSize = (2 + 2 + 1 + 1 + 1);
     }
 
     /* read logical screen descriptor block (LSDB) */
     static const size_t lsdbSize = (2 + 2 + 1 + 1 + 1);

-    m_f->Read(buf, lsdbSize);
-    if (m_f->LastRead() != lsdbSize)
+    stream.Read(buf, lsdbSize);
+    if (stream.LastRead() != lsdbSize)

     {
         return wxGIF_INVFORMAT;
     }
 
     {
         return wxGIF_INVFORMAT;
     }
 

-    m_screenw = buf[0] + 256 * buf[1];
-    m_screenh = buf[2] + 256 * buf[3];
+    m_szAnimation.SetWidth( buf[0] + 256 * buf[1] );
+    m_szAnimation.SetHeight( buf[2] + 256 * buf[3] );

 
 

-    const int maxScreenSize = 4 << 10;
-    if ((m_screenw <= 0) || (m_screenw > maxScreenSize) || (m_screenh <= 0) || (m_screenh > maxScreenSize))
+    if ((m_szAnimation.GetWidth() == 0) || (m_szAnimation.GetHeight() == 0))

     {
         return wxGIF_INVFORMAT;
     }
     {
         return wxGIF_INVFORMAT;
     }


@@ -684,32 +638,30 @@ int wxGIFDecoder::ReadGIF()
     /* load global color map if available */
     if ((buf[4] & 0x80) == 0x80)
     {
     /* load global color map if available */
     if ((buf[4] & 0x80) == 0x80)
     {

-        m_background = buf[5];
+        int backgroundColIndex = buf[5];

 
 

-        ncolors = 2 << (buf[4] & 0x07);
-        size_t numBytes = 3 * ncolors;
-        m_f->Read(pal, numBytes);
-        if (m_f->LastRead() != numBytes)
+        global_ncolors = 2 << (buf[4] & 0x07);
+        size_t numBytes = 3 * global_ncolors;
+        stream.Read(pal, numBytes);
+        if (stream.LastRead() != numBytes)

         {
             return wxGIF_INVFORMAT;
         }
         {
             return wxGIF_INVFORMAT;
         }

+
+        m_background.Set(pal[backgroundColIndex*3 + 0],
+                         pal[backgroundColIndex*3 + 1],
+                         pal[backgroundColIndex*3 + 2]);

     }
 
     /* transparent colour, disposal method and delay default to unused */
     transparent = -1;
     }
 
     /* transparent colour, disposal method and delay default to unused */
     transparent = -1;

-    disposal = -1;
+    disposal = wxANIM_UNSPECIFIED;

     delay = -1;
 
     delay = -1;
 

-    /* read images */
-    ppimg = &m_pfirst;
-    pprev = NULL;
-    pimg  = NULL;
-

     bool done = false;
     bool done = false;

-

     while (!done)
     {
     while (!done)
     {

-        type = (unsigned char)m_f->GetC();
+        type = (unsigned char)stream.GetC();

 
         /*
         If the end of file has been reached (or an error) and a ";"
 
         /*
         If the end of file has been reached (or an error) and a ";"


@@ -719,7 +671,7 @@ int wxGIFDecoder::ReadGIF()
         be decoded as far as possible). returning wxGIF_TRUNCATED is not
         possible here since some init code is done after this loop.
         */
         be decoded as far as possible). returning wxGIF_TRUNCATED is not
         possible here since some init code is done after this loop.
         */

-        if (m_f->Eof())// || !m_f->IsOk())
+        if (stream.Eof())// || !stream.IsOk())

         {
             /*
             type is set to some bogus value, so there's no
         {
             /*
             type is set to some bogus value, so there's no


@@ -737,12 +689,12 @@ int wxGIFDecoder::ReadGIF()
         /* extension block? */
         if (type == 0x21)
         {
         /* extension block? */
         if (type == 0x21)
         {

-            if (((unsigned char)m_f->GetC()) == 0xF9)
+            if (((unsigned char)stream.GetC()) == 0xF9)

             /* graphics control extension, parse it */
             {
                 static const size_t gceSize = 6;
             /* graphics control extension, parse it */
             {
                 static const size_t gceSize = 6;

-                m_f->Read(buf, gceSize);
-                if (m_f->LastRead() != gceSize)
+                stream.Read(buf, gceSize);
+                if (stream.LastRead() != gceSize)

                 {
                     Destroy();
                     return wxGIF_INVFORMAT;
                 {
                     Destroy();
                     return wxGIF_INVFORMAT;


@@ -756,19 +708,19 @@ int wxGIFDecoder::ReadGIF()
                     transparent = buf[4];
 
                 /* read disposal method */
                     transparent = buf[4];
 
                 /* read disposal method */

-                disposal = ((buf[1] & 0x1C) >> 2) - 1;
+                disposal = (wxAnimationDisposal)(((buf[1] & 0x1C) >> 2) - 1);

             }
             else
             /* other extension, skip */
             {
             }
             else
             /* other extension, skip */
             {

-                while ((i = (unsigned char)m_f->GetC()) != 0)
+                while ((i = (unsigned char)stream.GetC()) != 0)

                 {
                 {

-                    m_f->SeekI(i, wxFromCurrent);
-                    if (m_f->Eof())
+                    if (stream.Eof() || (stream.LastRead() == 0))

                     {
                         done = true;
                         break;
                     }
                     {
                         done = true;
                         break;
                     }

+                    stream.SeekI(i, wxFromCurrent);

                 }
             }
         }
                 }
             }
         }


@@ -777,7 +729,7 @@ int wxGIFDecoder::ReadGIF()
         if (type == 0x2C)
         {
             /* allocate memory for IMAGEN struct */
         if (type == 0x2C)
         {
             /* allocate memory for IMAGEN struct */

-            pimg = (*ppimg) = new GIFImage();
+            GIFImage *pimg = new GIFImage();

 
             if (pimg == NULL)
             {
 
             if (pimg == NULL)
             {


@@ -787,8 +739,8 @@ int wxGIFDecoder::ReadGIF()
 
             /* fill in the data */
             static const size_t idbSize = (2 + 2 + 2 + 2 + 1);
 
             /* fill in the data */
             static const size_t idbSize = (2 + 2 + 2 + 2 + 1);

-            m_f->Read(buf, idbSize);
-            if (m_f->LastRead() != idbSize)
+            stream.Read(buf, idbSize);
+            if (stream.LastRead() != idbSize)

             {
                 Destroy();
                 return wxGIF_INVFORMAT;
             {
                 Destroy();
                 return wxGIF_INVFORMAT;


@@ -803,7 +755,8 @@ int wxGIFDecoder::ReadGIF()
             pimg->w = buf[4] + 256 * buf[5];
             pimg->h = buf[6] + 256 * buf[7];
 
             pimg->w = buf[4] + 256 * buf[5];
             pimg->h = buf[6] + 256 * buf[7];
 

-            if ((pimg->w <= 0) || (pimg->w > maxScreenSize) || (pimg->h <= 0) || (pimg->h > maxScreenSize))
+            if ((pimg->w == 0) || (pimg->w > (unsigned int)m_szAnimation.GetWidth()) || 
+                (pimg->h == 0) || (pimg->h > (unsigned int)m_szAnimation.GetHeight()))

             {
                 Destroy();
                 return wxGIF_INVFORMAT;
             {
                 Destroy();
                 return wxGIF_INVFORMAT;


@@ -815,10 +768,6 @@ int wxGIFDecoder::ReadGIF()
             pimg->transparent = transparent;
             pimg->disposal = disposal;
             pimg->delay = delay;
             pimg->transparent = transparent;
             pimg->disposal = disposal;
             pimg->delay = delay;

-            pimg->next = NULL;
-            pimg->prev = pprev;
-            pprev = pimg;
-            ppimg = &pimg->next;

 
             /* allocate memory for image and palette */
             pimg->p   = (unsigned char *) malloc((size_t)size);
 
             /* allocate memory for image and palette */
             pimg->p   = (unsigned char *) malloc((size_t)size);


@@ -833,11 +782,11 @@ int wxGIFDecoder::ReadGIF()
             /* load local color map if available, else use global map */
             if ((buf[8] & 0x80) == 0x80)
             {
             /* load local color map if available, else use global map */
             if ((buf[8] & 0x80) == 0x80)
             {

-                ncolors = 2 << (buf[8] & 0x07);
-                size_t numBytes = 3 * ncolors;
-                if (numBytes > 0)
-                    m_f->Read(pimg->pal, numBytes);
-                if ((numBytes <= 0) || (m_f->LastRead() != numBytes))
+                unsigned int local_ncolors = 2 << (buf[8] & 0x07);
+                size_t numBytes = 3 * local_ncolors;
+                stream.Read(pimg->pal, numBytes);
+                pimg->ncolours = local_ncolors;
+                if (stream.LastRead() != numBytes)

                 {
                     Destroy();
                     return wxGIF_INVFORMAT;
                 {
                     Destroy();
                     return wxGIF_INVFORMAT;


@@ -846,10 +795,11 @@ int wxGIFDecoder::ReadGIF()
             else
             {
                 memcpy(pimg->pal, pal, 768);
             else
             {
                 memcpy(pimg->pal, pal, 768);

+                pimg->ncolours = global_ncolors;

             }
 
             /* get initial code size from first byte in raster data */
             }
 
             /* get initial code size from first byte in raster data */

-            bits = (unsigned char)m_f->GetC();
+            bits = (unsigned char)stream.GetC();

             if (bits == 0)
             {
                 Destroy();
             if (bits == 0)
             {
                 Destroy();


@@ -857,56 +807,59 @@ int wxGIFDecoder::ReadGIF()
             }
 
             /* decode image */
             }
 
             /* decode image */

-            int result = dgif(pimg, interl, bits);
+            wxGIFErrorCode result = dgif(stream, pimg, interl, bits);

             if (result != wxGIF_OK)
             {
                 Destroy();
                 return result;
             }
             if (result != wxGIF_OK)
             {
                 Destroy();
                 return result;
             }

-            m_nimages++;
+
+            /* add the image to our frame array */
+            m_frames.Add((void*)pimg);
+            m_nFrames++;

 
             /* if this is not an animated GIF, exit after first image */
 
             /* if this is not an animated GIF, exit after first image */

-            if (!m_anim)
+            if (!anim)

                 done = true;
         }
     }
 
                 done = true;
         }
     }
 

-    if (m_nimages <= 0)
+    if (m_nFrames <= 0)

     {
         Destroy();
         return wxGIF_INVFORMAT;
     }
 
     {
         Destroy();
         return wxGIF_INVFORMAT;
     }
 

-    /* setup image pointers */
-    m_image = 1;
-    m_plast = pimg;
-    m_pimage = m_pfirst;
-

     /* try to read to the end of the stream */
     while (type != 0x3B)
     {
     /* try to read to the end of the stream */
     while (type != 0x3B)
     {

-        if (!m_f->IsOk())
+        if (!stream.IsOk())

             return wxGIF_TRUNCATED;
 
             return wxGIF_TRUNCATED;
 

-        type = (unsigned char)m_f->GetC();
+        type = (unsigned char)stream.GetC();

 
         if (type == 0x21)
         {
             /* extension type */
 
         if (type == 0x21)
         {
             /* extension type */

-            (void) m_f->GetC();
+            (void) stream.GetC();

 
             /* skip all data */
 
             /* skip all data */

-            while ((i = (unsigned char)m_f->GetC()) != 0)
+            while ((i = (unsigned char)stream.GetC()) != 0)

             {
             {

-                m_f->SeekI(i, wxFromCurrent);
+                if (stream.Eof() || (stream.LastRead() == 0))
+                {
+                    Destroy();
+                    return wxGIF_INVFORMAT;
+                }
+                stream.SeekI(i, wxFromCurrent);

             }
         }
         else if (type == 0x2C)
         {
             /* image descriptor block */
             static const size_t idbSize = (2 + 2 + 2 + 2 + 1);
             }
         }
         else if (type == 0x2C)
         {
             /* image descriptor block */
             static const size_t idbSize = (2 + 2 + 2 + 2 + 1);

-            m_f->Read(buf, idbSize);
-            if (m_f->LastRead() != idbSize)
+            stream.Read(buf, idbSize);
+            if (stream.LastRead() != idbSize)

             {
                 Destroy();
                 return wxGIF_INVFORMAT;
             {
                 Destroy();
                 return wxGIF_INVFORMAT;


@@ -915,30 +868,28 @@ int wxGIFDecoder::ReadGIF()
             /* local color map */
             if ((buf[8] & 0x80) == 0x80)
             {
             /* local color map */
             if ((buf[8] & 0x80) == 0x80)
             {

-                ncolors = 2 << (buf[8] & 0x07);
-                if (ncolors <= 0)
-                {
-                    Destroy();
-                    return wxGIF_INVFORMAT;
-                }
-
-                wxFileOffset pos = m_f->TellI();
-                wxFileOffset numBytes = 3 * ncolors;
-                m_f->SeekI(numBytes, wxFromCurrent);
-                if (m_f->TellI() != (pos + numBytes))
-                {
-                    Destroy();
-                    return wxGIF_INVFORMAT;
-                }
+                unsigned int local_ncolors = 2 << (buf[8] & 0x07);
+                wxFileOffset numBytes = 3 * local_ncolors;
+                stream.SeekI(numBytes, wxFromCurrent);

             }
 
             /* initial code size */
             }
 
             /* initial code size */

-            (void) m_f->GetC();
+            (void) stream.GetC();
+            if (stream.Eof() || (stream.LastRead() == 0))
+            {
+                Destroy();
+                return wxGIF_INVFORMAT;
+            }

 
             /* skip all data */
 
             /* skip all data */

-            while ((i = (unsigned char)m_f->GetC()) != 0)
+            while ((i = (unsigned char)stream.GetC()) != 0)

             {
             {

-                m_f->SeekI(i, wxFromCurrent);
+                if (stream.Eof() || (stream.LastRead() == 0))
+                {
+                    Destroy();
+                    return wxGIF_INVFORMAT;
+                }
+                stream.SeekI(i, wxFromCurrent);

             }
         }
         else if ((type != 0x3B) && (type != 00)) /* testing */
             }
         }
         else if ((type != 0x3B) && (type != 00)) /* testing */