Fixed heap corruption when reading a corrupted RLE TGA image.

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

diff --git a/src/common/imaggif.cpp b/src/common/imaggif.cpp
index ddcce30a7f18f947f48f8af61d61a9849db5849e..e07eb27cb07d5b74a8eed38a81e5d1f315f8c064 100644 (file)
--- a/src/common/imaggif.cpp
+++ b/src/common/imaggif.cpp
@@ -1,454 +1,811 @@
 /////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////

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

 // Purpose:     wxGIFHandler
 // Purpose:     wxGIFHandler

-// Author:      Guillermo Rodriguez Garcia
-//              wxWindows adaptation by Vaclav Slavik
+// Author:      Vaclav Slavik, Guillermo Rodriguez Garcia, Gershon Elber, Troels K
+// RCS-ID:      $Id$
+// Copyright:   (c) 1999-2011 Vaclav Slavik, Guillermo Rodriguez Garcia, Gershon Elber, Troels K

 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 

-#ifdef __GNUG__
-#pragma implementation "imaggif.h"
-#endif
-

 // For compilers that support precompilation, includes "wx.h".
 // For compilers that support precompilation, includes "wx.h".

-#include <wx/wxprec.h>
+#include "wx/wxprec.h"

 
 #ifdef __BORLANDC__
 
 #ifdef __BORLANDC__

-#pragma hdrstop
+    #pragma hdrstop

 #endif
 
 #endif
 

-#include <wx/wx.h>
+#if wxUSE_IMAGE && wxUSE_GIF
+
+#ifndef WX_PRECOMP
+    #include "wx/intl.h"
+    #include "wx/log.h"
+    #include "wx/palette.h"
+    #include "wx/utils.h"
+#endif

 
 

-#include <wx/image.h>
-#include <wx/wfstream.h>
-#include <wx/module.h>
+#include "wx/imaggif.h"
+#include "wx/gifdecod.h"
+#include "wx/stream.h"
+#include "wx/anidecod.h" // wxImageArray

 
 

-#include <wx/imaggif.h>
+#define GIF89_HDR     "GIF89a"
+#define NETSCAPE_LOOP "NETSCAPE2.0"

 
 

-/*
+// see members.aol.com/royalef/gifabout.htm
+//     members.aol.com/royalef/gif89a.txt

 
 

-FOLLOWING CODE IS BY G.R.G. :
-(except wxInputStream stuff)
+enum
+{
+    GIF_MARKER_EXT       = '!', // 0x21
+    GIF_MARKER_SEP       = ',', // 0x2C
+    GIF_MARKER_ENDOFDATA = ';', // 0x3B
+
+    GIF_MARKER_EXT_GRAPHICS_CONTROL = 0xF9,
+    GIF_MARKER_EXT_COMMENT          = 0xFE,
+    GIF_MARKER_EXT_APP              = 0xFF
+};

 
 

-*/
+#define LZ_MAX_CODE         4095    // Biggest code possible in 12 bits.
+#define FLUSH_OUTPUT        4096    // Impossible code, to signal flush.
+#define FIRST_CODE          4097    // Impossible code, to signal first.

 
 

-/************************************************************************
-  READGIF.H - Leer un archivo GIF de 8 bits
- ------------------------------------------------------------------------
-  Tratamiento Digital de la Imagen
- ------------------------------------------------------------------------
-  Guillermo Rodriguez Garcia
-  <guille@iies.es>
+#define HT_SIZE         8192        // 12bits = 4096 or twice as big!
+#define HT_KEY_MASK     0x1FFF      // 13bits keys

 
 

-  Version: 2.0
-*************************************************************************/
+#define HT_GET_KEY(l)   (l >> 12)
+#define HT_GET_CODE(l)  (l & 0x0FFF)
+#define HT_PUT_KEY(l)   (l << 12)
+#define HT_PUT_CODE(l)  (l & 0x0FFF)

 
 

-typedef struct
+struct wxRGB

 {
 {

-    int w;                  /* width */
-    int h;                  /* height */
-    unsigned char *p;       /* bitmap */
-    unsigned char *pal;     /* palette */
-} IMAGEN;
+    wxUint8 red;
+    wxUint8 green;
+    wxUint8 blue;
+};

 
 

+struct GifHashTableType
+{
+    wxUint32 HTable[HT_SIZE];
+};

 
 

-/************************************************************************
-  READGIF.C - Lee un archivo GIF de 256 colores
- ------------------------------------------------------------------------
-  Tratamiento Digital de la Imagen
- ------------------------------------------------------------------------
-  Guillermo Rodriguez Garcia
-  <guille@iies.es>
+/*static*/ wxString wxGIFHandler::ms_comment;

 
 

-  Version: 2.0
-*************************************************************************/
+IMPLEMENT_DYNAMIC_CLASS(wxGIFHandler,wxImageHandler)

 
 

+//----------------------------------------------------------------------------
+// Forward declarations
+//----------------------------------------------------------------------------

 
 

-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+static int wxGIFHandler_KeyItem(unsigned long item);

 
 

+#if wxUSE_STREAMS

 
 

-/* error codes */
-#define E_OK        0               /* everything was OK */
-#define E_ARCHIVO   -1              /* error opening file */
-#define E_FORMATO   -2              /* error in gif header */
-#define E_MEMORIA   -3              /* error allocating memory */
+static int wxGIFHandler_BitSize(int n);

 
 

+#if wxUSE_PALETTE
+static bool wxGIFHandler_GetPalette(const wxImage& image,
+    wxRGB *pal, int *palCount, int *mask_index);
+#endif
+static
+int wxGIFHandler_PaletteFind(const wxRGB& clr, const wxRGB *array, int count);
+
+static bool wxGIFHandler_Write(wxOutputStream *, const void *buf, size_t len);
+static bool wxGIFHandler_WriteByte(wxOutputStream *, wxUint8);
+static bool wxGIFHandler_WriteWord(wxOutputStream *, wxUint16);
+static bool wxGIFHandler_WriteHeader(wxOutputStream *, int width, int height,
+    bool loop, const wxRGB *pal, int palCount,
+    const wxString& comment = wxEmptyString);
+static bool wxGIFHandler_WriteRect(wxOutputStream *, int width, int height);
+#if wxUSE_PALETTE
+static bool wxGIFHandler_WriteTerm(wxOutputStream *);
+#endif
+static bool wxGIFHandler_WriteZero(wxOutputStream *);
+static bool wxGIFHandler_WritePalette(wxOutputStream *,
+    const wxRGB *pal, size_t palCount, int bpp);
+static bool wxGIFHandler_WriteControl(wxOutputStream *,
+    int maskIndex, int delayMilliSecs);
+static bool wxGIFHandler_WriteComment(wxOutputStream *, const wxString&);
+static bool wxGIFHandler_WriteLoop(wxOutputStream *);

 
 

-/* This class binding is by VS, so all bugs in it are mine ;-) */
+static bool wxGIFHandler_BufferedOutput(wxOutputStream *, wxUint8 *buf, int c);
+#endif // wxUSE_STREAMS

 
 

-class gifDecoder
+//-----------------------------------------------------------------------------
+// wxGIFHandler
+//-----------------------------------------------------------------------------
+
+#if wxUSE_STREAMS
+
+bool wxGIFHandler::LoadFile(wxImage *image, wxInputStream& stream,
+    bool verbose, int index)

 {
 {

-    private:
-        /* globals */
-        int            restbits;            /* remaining valid bits */
-        unsigned int   restbyte;            /* remaining bytes in this block */
-        unsigned int   lastbyte;            /* last byte read */
+    wxGIFDecoder *decod;
+    wxGIFErrorCode error;
+    bool ok = true;

 
 

-        unsigned char* file;                /* input file in memory */
-        unsigned int   file_pos, file_size; /* position & size in it */
+//    image->Destroy();
+    decod = new wxGIFDecoder();
+    error = decod->LoadGIF(stream);

 
 

-        int fgetc();
-        void fread(void *ptr, size_t size, size_t nmemb);
-        void fseekcur(int rel_pos);
+    if ((error != wxGIF_OK) && (error != wxGIF_TRUNCATED))
+    {
+        if (verbose)
+        {
+            switch (error)
+            {
+                case wxGIF_INVFORMAT:
+                    wxLogError(_("GIF: error in GIF image format."));
+                    break;
+                case wxGIF_MEMERR:
+                    wxLogError(_("GIF: not enough memory."));
+                    break;
+                default:
+                    wxLogError(_("GIF: unknown error!!!"));
+                    break;
+            }
+        }
+        delete decod;
+        return false;
+    }

 
 

-    public:
-        gifDecoder(unsigned char* mem, int sz) {file = mem; file_pos = 0; file_size = sz;}
-        int getcode(int bits);
-        int dgif(IMAGEN *img, int interl, int bits);
-        int readgif(IMAGEN *img);
-};
+    if ((error == wxGIF_TRUNCATED) && verbose)
+    {
+        wxLogError(_("GIF: data stream seems to be truncated."));
+        // go on; image data is OK
+    }

 
 

+    if (ok)
+    {
+        ok = decod->ConvertToImage(index != -1 ? (size_t)index : 0, image);
+    }
+    else
+    {
+        wxLogError(_("GIF: Invalid gif index."));
+    }
+
+    delete decod;

 
 

-int gifDecoder::fgetc()
+    return ok;
+}
+
+bool wxGIFHandler::SaveFile(wxImage *image,
+    wxOutputStream& stream, bool verbose)

 {
 {

-    if (file_pos < file_size) return file[file_pos++];
-    else return EOF;
+#if wxUSE_PALETTE
+    wxRGB pal[256];
+    int palCount;
+    int maskIndex;
+
+    return wxGIFHandler_GetPalette(*image, pal, &palCount, &maskIndex)
+        && DoSaveFile(*image, &stream, verbose, true /*first?*/, 0,
+            false /*loop?*/, pal, palCount, maskIndex, ms_comment)
+        && wxGIFHandler_WriteTerm(&stream);
+#else
+    wxUnusedVar(image);
+    wxUnusedVar(stream);
+    wxUnusedVar(verbose);
+    return false;
+#endif

 }
 
 }
 

-void gifDecoder::fread(void *ptr, size_t size, size_t nmemb)
+bool wxGIFHandler::DoCanRead( wxInputStream& stream )

 {
 {

-    int todo = size * nmemb;
-    if (todo + file_pos > file_size) todo = file_size - file_pos;
-    memcpy(ptr, file + file_pos, todo);
-    file_pos += todo;
+    wxGIFDecoder decod;
+    return decod.CanRead(stream);
+         // it's ok to modify the stream position here

 }
 
 }
 

-void gifDecoder::fseekcur(int rel_pos)
+int wxGIFHandler::DoGetImageCount( wxInputStream& stream )

 {
 {

-    file_pos += rel_pos;
+    wxGIFDecoder decod;
+    wxGIFErrorCode error = decod.LoadGIF(stream);
+    if ( (error != wxGIF_OK) && (error != wxGIF_TRUNCATED) )
+        return -1;
+
+    // NOTE: this function modifies the current stream position but it's ok
+    //       (see wxImageHandler::GetImageCount)
+
+    return decod.GetFrameCount();

 }
 
 }
 

-/* getcode:
- *  Reads the next code from the file, with size 'bits'
- *  v2.0 - changed to support 'bits' values < 8
- */
-int gifDecoder::getcode(int bits)
+bool wxGIFHandler::DoSaveFile(const wxImage& image, wxOutputStream *stream,
+    bool WXUNUSED(verbose), bool first, int delayMilliSecs, bool loop,
+    const wxRGB *pal, int palCount, int maskIndex, const wxString& comment)

 {
 {

-    unsigned int    mask;           /* bit mask */
-    unsigned int    code;           /* code (result) */
+    const unsigned long colorcount = image.CountColours(256+1);
+    bool ok = colorcount && (colorcount <= 256);
+    if (!ok)
+    {
+        return false;
+    }
+
+    int width = image.GetWidth();
+    int height = image.GetHeight();
+    int width_even = width + ((width % 2) ? 1 : 0);

 
 

+    if (first)
+    {
+        ok = wxGIFHandler_WriteHeader(stream, width, height, loop,
+            pal, palCount, comment);
+    }

 
 

-    /* get remaining bits from last byte read */
-    mask = (1 << bits) - 1;
-    code = (lastbyte >> (8 - restbits)) & mask;
+    ok = ok && wxGIFHandler_WriteControl(stream, maskIndex, delayMilliSecs)
+        && wxGIFHandler_WriteByte(stream, GIF_MARKER_SEP)
+        && wxGIFHandler_WriteRect(stream, width, height);

 
 

-    /* keep reading new bytes until needed */
-    while (bits > restbits)
+    // local palette
+    if (first)

     {
     {

-        /* if no bytes left in this block, read the next block */
-        if (restbyte == 0)
-            restbyte = fgetc();
+        // we already saved the (global) palette
+        ok = ok && wxGIFHandler_WriteZero(stream);
+    }
+    else
+    {
+        const int bpp = wxGIFHandler_BitSize(palCount);
+        wxUint8 b;

 
 

-        /* read next byte and isolate the bits we need */
-        lastbyte = fgetc();
-        mask     = (1 << (bits - restbits)) - 1;
-        code     = code + ((lastbyte & mask) << restbits);
-        restbyte--;
+        b = 0x80;
+        b |=(bpp - 1) << 5;
+        b |=(bpp - 1);
+        b &=~0x40; // clear interlaced

 
 

-        /* adjust total number of bits extracted from the buffer */
-        restbits = restbits + 8;
+        ok = ok && wxGIFHandler_WriteByte(stream, b)
+            && wxGIFHandler_WritePalette(stream, pal, palCount, bpp);

     }
 
     }
 

-    /* find number of bits reamining for next code */
-    restbits = (restbits - bits);
+    if (!ok)
+    {
+        return false;
+    }

 
 

-    return code;
-}
+    if (!InitHashTable())
+    {
+        wxLogError(_("Couldn't initialize GIF hash table."));
+        return false;
+    }
+
+    const wxUint8 *src = image.GetData();
+    wxUint8 *eightBitData = new wxUint8[width];
+
+    SetupCompress(stream, 8);

 
 

-/* dgif:
- *  GIF decoding function. The initial code size (aka root size)
- *  is 'bits'. Supports interlaced images (interl == 1).
- */
-int gifDecoder::dgif(IMAGEN *img, int interl, int bits)
-{
-    int ab_prefix[4096];        /* alphabet (prefixes) */
-    int ab_tail[4096];          /* alphabet (tails) */
-    int stack[4096];            /* decompression stack */
-
-    int ab_clr;                 /* clear code */
-    int ab_fin;                 /* end of info code */
-    int ab_bits;                /* actual symbol width, in bits */
-    int ab_free;                /* first free position in alphabet */
-    int ab_max;                 /* last possible character in alphabet */
-    int pass;                   /* pass number in interlaced images */
-    int pos;                    /* index into decompresion stack */
-    int x, y;                   /* position in image buffer */
-
-    int code, readcode, lastcode, abcabca;
-
-    /* these won't change */
-    ab_clr  = (1 << bits);
-    ab_fin  = (1 << bits) + 1;
-
-    /* these will change through the decompression proccess */
-    ab_bits  = bits + 1;
-    ab_free  = (1 << bits) + 2;
-    ab_max   = (1 << ab_bits) - 1;
-    lastcode = -1;
-    abcabca  = -1;
-    pass     = 1;
-    pos = x = y = 0;
-
-    /* reset static globals */
-    restbits = 0;
-    restbyte = 0;
-    lastbyte = 0;
-
-    do
-    {
-        /* get next code */
-        readcode = code = getcode(ab_bits);
-
-        /* end of image? */
-        if (code == ab_fin) break;
-
-        /* reset alphabet? */
-        if (code == ab_clr)
+    m_pixelCount = height * width_even;
+    for (int y = 0; y < height; y++)
+    {
+        m_pixelCount -= width_even;
+        for (int x = 0; x < width; x++)

         {
         {

-            /* reset main variables */
-            ab_bits  = bits + 1;
-            ab_free  = (1 << bits) + 2;
-            ab_max   = (1 << ab_bits) - 1;
-            lastcode = -1;
-            abcabca  = -1;
-
-            /* skip to next code */
-            continue;
+            wxRGB rgb;
+            rgb.red   = src[0];
+            rgb.green = src[1];
+            rgb.blue  = src[2];
+            int index = wxGIFHandler_PaletteFind(rgb, pal, palCount);
+            wxASSERT(index != wxNOT_FOUND);
+            eightBitData[x] = (wxUint8)index;
+            src+=3;

         }
 
         }
 

-        /* unknown code: special case (like in ABCABCA) */
-        if (code >= ab_free)
+        ok = CompressLine(stream, eightBitData, width);
+        if (!ok)

         {
         {

-            code = lastcode;            /* take last string */
-            stack[pos++] = abcabca;     /* add first character */
+            break;

         }
         }

+    }
+
+    delete [] eightBitData;
+
+    wxDELETE(m_hashTable);

 
 

-        /* build the string for this code in the stack */
-        while (code > ab_clr)
+    return ok;
+}
+
+bool wxGIFHandler::SaveAnimation(const wxImageArray& images,
+    wxOutputStream *stream, bool verbose, int delayMilliSecs,
+    const wxString& comment)
+{
+#if wxUSE_PALETTE
+    bool ok = true;
+    size_t i;
+
+    wxSize size(0,0);
+    for (i = 0; (i < images.GetCount()) && ok; i++)
+    {
+        const wxImage& image = images.Item(i);
+        wxSize temp(image.GetWidth(), image.GetHeight());
+        ok = ok && image.HasPalette();
+        if (i)

         {
         {

-            stack[pos++] = ab_tail[code];
-            code         = ab_prefix[code];
+           ok = ok && (size == temp);

         }
         }

-        stack[pos] = code;              /* push last code into the stack */
-        abcabca    = code;              /* save for special case */
-
-        /* make new entry in alphabet (only if NOT just cleared) */
-        if (lastcode != -1)
+        else

         {
         {

-            ab_prefix[ab_free] = lastcode;
-            ab_tail[ab_free]   = code;
-            ab_free++;
+           size = temp;
+        }
+    }
+
+    for (i = 0; (i < images.GetCount()) && ok; i++)
+    {
+        const wxImage& image = images.Item(i);
+
+        wxRGB pal[256];
+        int palCount;
+        int maskIndex;
+
+        ok = wxGIFHandler_GetPalette(image, pal, &palCount, &maskIndex)
+          && DoSaveFile(image, stream, verbose, i == 0 /*first?*/, delayMilliSecs,
+            true /*loop?*/, pal, palCount, maskIndex,
+            comment.length() ? comment : ms_comment);
+    }

 
 

-            if ((ab_free > ab_max) && (ab_bits < 12))
+    return ok && wxGIFHandler_WriteTerm(stream);
+#else
+    wxUnusedVar(images);
+    wxUnusedVar(stream);
+    wxUnusedVar(verbose);
+    wxUnusedVar(delayMilliSecs);
+    wxUnusedVar(comment);
+
+    return false;
+#endif
+}
+
+bool wxGIFHandler::CompressOutput(wxOutputStream *stream, int code)
+{
+    if (code == FLUSH_OUTPUT)
+    {
+        while (m_crntShiftState > 0)
+        {
+            // Get rid of what is left in DWord, and flush it.
+            if (!wxGIFHandler_BufferedOutput(stream, m_LZBuf,
+                m_crntShiftDWord & 0xff))

             {
             {

-                ab_bits++;
-                ab_max = (1 << ab_bits) - 1;
+                return false;

             }
             }

+            m_crntShiftDWord >>= 8;
+            m_crntShiftState -= 8;

         }
         }

-
-        /* dump stack data to the buffer */
-        while (pos >= 0)
+        m_crntShiftState = 0;                       // For next time.
+        if (!wxGIFHandler_BufferedOutput(stream, m_LZBuf, FLUSH_OUTPUT))
+        {
+            return false;
+        }
+    }
+    else
+    {
+        m_crntShiftDWord |= ((long) code) << m_crntShiftState;
+        m_crntShiftState += m_runningBits;
+        while (m_crntShiftState >= 8)

         {
         {

-            (img->p)[x + (y * (img->w))] = (char)stack[pos--];
+            // Dump out full bytes:
+            if (!wxGIFHandler_BufferedOutput(stream, m_LZBuf,
+                m_crntShiftDWord & 0xff))
+            {
+                return false;
+            }
+            m_crntShiftDWord >>= 8;
+            m_crntShiftState -= 8;
+        }
+    }
+
+    // If code can't fit into RunningBits bits, must raise its size. Note
+    // however that codes above LZ_MAX_CODE are used for special signaling.
+    if ( (m_runningCode >= m_maxCode1) && (code <= LZ_MAX_CODE))
+    {
+        m_maxCode1 = 1 << ++m_runningBits;
+    }
+    return true;
+}
+
+bool wxGIFHandler::SetupCompress(wxOutputStream *stream, int bpp)
+{
+    m_LZBuf[0] = 0;           // Nothing was output yet.
+    m_clearCode = (1 << bpp);
+    m_EOFCode = m_clearCode + 1;
+    m_runningCode = m_EOFCode + 1;
+    m_runningBits = bpp + 1;     // Number of bits per code.
+    m_maxCode1 = 1 << m_runningBits;       // Max. code + 1.
+    m_crntCode = FIRST_CODE;       // Signal that this is first one!
+    m_crntShiftState = 0;      // No information in CrntShiftDWord.
+    m_crntShiftDWord = 0;
+
+    // Clear hash table and send Clear to make sure the decoder does the same.
+    ClearHashTable();
+
+    return wxGIFHandler_WriteByte(stream, (wxUint8)bpp)
+        && CompressOutput(stream, m_clearCode);
+}

 
 

-            if (++x >= (img->w))
+bool wxGIFHandler::CompressLine(wxOutputStream *stream,
+    const wxUint8 *line, int lineLen)
+{
+    int i = 0, crntCode, newCode;
+    unsigned long newKey;
+    wxUint8 pixel;
+    if (m_crntCode == FIRST_CODE)                  // It's first time!
+        crntCode = line[i++];
+    else
+        crntCode = m_crntCode;     // Get last code in compression.
+
+    while (i < lineLen)
+    {
+        // Decode lineLen items.
+        pixel = line[i++];                    // Get next pixel from stream.
+        // Form a new unique key to search hash table for the code combines
+        // crntCode as Prefix string with Pixel as postfix char.
+        newKey = (((unsigned long) crntCode) << 8) + pixel;
+        if ((newCode = ExistsHashTable(newKey)) >= 0)
+        {
+            // This Key is already there, or the string is old one, so
+            // simply take new code as our crntCode:
+            crntCode = newCode;
+        }
+        else
+        {
+            // Put it in hash table, output the prefix code, and make our
+            // crntCode equal to Pixel.
+            if (!CompressOutput(stream, crntCode))

             {
             {

-                x = 0;
+                return false;
+            }

 
 

-                if (interl)
-                {
-                    /* support for interlaced images */
-                    switch (pass)
-                    {
-                        case 1: y += 8; break;
-                        case 2: y += 8; break;
-                        case 3: y += 4; break;
-                        case 4: y += 2; break;
-                    }
-                    if (y >= (img->h))
-                    {
-                        switch (++pass)
-                        {
-                            case 2: y = 4; break;
-                            case 3: y = 2; break;
-                            case 4: y = 1; break;
-                        }
-                    }
-                }
-                else
+            crntCode = pixel;
+
+            // If however the HashTable is full, we send a clear first and
+            // Clear the hash table.
+            if (m_runningCode >= LZ_MAX_CODE)
+            {
+                // Time to do some clearance:
+                if (!CompressOutput(stream, m_clearCode))

                 {
                 {

-                    /* non-interlaced */
-                    y++;
+                    return false;

                 }
                 }

+
+                m_runningCode = m_EOFCode + 1;
+                m_runningBits = 8 + 1;
+                m_maxCode1 = 1 << m_runningBits;
+                ClearHashTable();
+            }
+            else
+            {
+                // Put this unique key with its relative Code in hash table:
+                InsertHashTable(newKey, m_runningCode++);

             }
         }
             }
         }

-
-        pos = 0;
-        lastcode = readcode;

     }
     }

-    while (code != ab_fin);
+    // Preserve the current state of the compression algorithm:
+    m_crntCode = crntCode;
+    if (m_pixelCount == 0)
+    {
+        // We are done - output last Code and flush output buffers:
+        if (!CompressOutput(stream, crntCode)
+            || !CompressOutput(stream, m_EOFCode)
+            || !CompressOutput(stream, FLUSH_OUTPUT))
+        {
+            return false;
+        }
+    }

 
 

-    return 0;
+    return true;

 }
 
 }
 

-/* readgif:
- *  Reads a GIF image from the file with filename 'nombre' in the
- *  IMAGEN structure pointed by 'img'. Can read GIFs with any bit
- *  size (color depth), but the output image is always expanded
- *  to 8 bits per pixel. Also, the image palette always contains
- *  256 colors, although some of them may be unused. Returns E_OK
- *  (== 0) on success, or an error code if something fails. Error
- *  codes are E_ARCHIVO, E_FORMATO, E_MEMORIA (see above).
- */
-int gifDecoder::readgif(IMAGEN *img)
+#endif  // wxUSE_STREAMS
+
+bool wxGIFHandler::InitHashTable()

 {
 {

-    int             size, ncolors, bits, interl, i;
-    unsigned char   pal[768];
-    unsigned char   buf[16];
+    if (!m_hashTable)
+    {
+        m_hashTable = new GifHashTableType();
+    }
+
+    if (!m_hashTable)
+    {
+        return false;
+    }

 
 

+    ClearHashTable();

 
 

-    /* read header and logical screen descriptor block (LSDB) */
-    fread(buf, 1, 13);
+    return true;
+}

 
 

-    /* check GIF signature */
-    if (memcmp(buf, "GIF", 3) != 0) return E_FORMATO;
+void wxGIFHandler::ClearHashTable()
+{
+    int index = HT_SIZE;
+    wxUint32 *HTable = m_hashTable->HTable;

 
 

-    /* load global color map if available */
-    if ((buf[10] & 0x80) == 0x80)
+    while (--index>=0)

     {
     {

-        ncolors = 2 << (buf[10] & 0x07);
-        fread(pal, 1, 3 * ncolors);
+        HTable[index] = 0xfffffffful;

     }
     }

+}

 
 

-    /* skip extensions */
-    while (fgetc() == 0x21)            /* separator */
-    {
-        fgetc();                       /* function code */
+void wxGIFHandler::InsertHashTable(unsigned long key, int code)
+{
+    int hKey = wxGIFHandler_KeyItem(key);
+    wxUint32 *HTable = m_hashTable->HTable;

 
 

-        while ((i = fgetc()) != 0)     /* byte count */
-            fseekcur(i);
+    while (HT_GET_KEY(HTable[hKey]) != 0xFFFFFL)
+    {
+        hKey = (hKey + 1) & HT_KEY_MASK;

     }
     }

+    HTable[hKey] = HT_PUT_KEY(key) | HT_PUT_CODE(code);
+}

 
 

-    /* read image descriptor block (IDB) */
-    fread(buf, 1, 9);
-    img->w = buf[4] + 256 * buf[5];

 
 

-    img->h = buf[6] + 256 * buf[7];
-    size   = img->w * img->h;
-    interl = ((buf[8] & 0x40)? 1 : 0);
+int wxGIFHandler::ExistsHashTable(unsigned long key)
+{
+    int hKey = wxGIFHandler_KeyItem(key);
+    wxUint32 *HTable = m_hashTable->HTable, HTKey;

 
 

-    /* load local color map if available */
-    if ((buf[8] & 0x80) == 0x80)
+    while ((HTKey = HT_GET_KEY(HTable[hKey])) != 0xFFFFFL)

     {
     {

-        ncolors = 2 << (buf[8] & 0x07);
-        fread(pal, 1, 3 * ncolors);
+        if (key == HTKey)
+        {
+            return HT_GET_CODE(HTable[hKey]);
+        }
+        hKey = (hKey + 1) & HT_KEY_MASK;

     }
     }

+    return -1;
+}

 
 

-    /* get initial code size from first byte in raster data */
-    bits = fgetc();
-
-    /* allocate memory for image and palette */
-    if ((img->p   = (unsigned char*) malloc(size)) == NULL) return E_MEMORIA;
-    if ((img->pal = (unsigned char*) malloc(768))  == NULL) return E_MEMORIA;
+// ---------------------------------------------------------------------------
+// implementation of global private functions
+// ---------------------------------------------------------------------------

 
 

-    /* shift palette to fit VGA 6-bit format */
-    for (i = 0; i < 768; i++)
-        (img->pal)[i] = (unsigned char)pal[i] /* >> 2 not needed under wxWin */;
+int wxGIFHandler_KeyItem(unsigned long item)
+{
+    return ((item >> 12) ^ item) & HT_KEY_MASK;
+}

 
 

-    /* decode GIF */
-    dgif(img, interl, bits);
+#if wxUSE_STREAMS

 
 

-    /* finish successfully :-) */
-    return E_OK;
+int wxGIFHandler_BitSize(int n)
+{
+    int i;
+    for (i = 1; i <= 8; i++)
+    {
+        if ((1 << i) >= n)
+        {
+            break;
+        }
+    }
+    return i;

 }
 
 }
 

-/*
+#if wxUSE_PALETTE
+bool wxGIFHandler_GetPalette(const wxImage& image,
+    wxRGB *pal, int *pPalCount, int *pMaskIndex)
+{
+    if (!image.HasPalette())
+    {
+        return false;
+    }

 
 

-FOLLOWING CODE IS BY V.S. :
+    const wxPalette& palette = image.GetPalette();
+    int palCount = palette.GetColoursCount();

 
 

-*/
+    for (int i = 0; i < palCount; ++i)
+    {
+        if (!palette.GetRGB(i, &pal[i].red, &pal[i].green, &pal[i].blue))
+        {
+            break;
+        }
+    }
+    if (image.HasMask())
+    {
+        wxRGB mask;

 
 

-//-----------------------------------------------------------------------------
-// wxGIFHandler
-//-----------------------------------------------------------------------------
+        mask.red   = image.GetMaskRed();
+        mask.green = image.GetMaskGreen();
+        mask.blue  = image.GetMaskBlue();
+        *pMaskIndex = wxGIFHandler_PaletteFind(mask, pal, palCount);
+        if ( (*pMaskIndex == wxNOT_FOUND) && (palCount < 256))
+        {
+            *pMaskIndex = palCount;
+            pal[palCount++] = mask;
+        }
+    }
+    else
+    {
+        *pMaskIndex = wxNOT_FOUND;
+    }
+    *pPalCount = palCount;

 
 

-IMPLEMENT_DYNAMIC_CLASS(wxGIFHandler,wxImageHandler)
+    return true;
+}
+#endif // wxUSE_PALETTE

 
 

-bool wxGIFHandler::LoadFile( wxImage *image, wxInputStream& stream )
+int wxGIFHandler_PaletteFind(const wxRGB& clr, const wxRGB *array, int count)

 {
 {

-    unsigned char *ptr, *src, *pal;
-    int file_size;
-    unsigned char* file_con;
-    IMAGEN igif;
-    int i;
-    gifDecoder *decod;
+    for (int i = 0; i < count; i++)
+    {
+        if (   (clr.red   == array[i].red)
+            && (clr.green == array[i].green)
+            && (clr.blue  == array[i].blue))
+        {
+            return i;
+        }
+    }

 
 

-    image->Destroy();
+    return wxNOT_FOUND;
+}

 
 

-    file_size = stream.StreamSize();
-    file_con = (unsigned char*) malloc(file_size);
-    stream.Read(file_con, file_size);
-    decod = new gifDecoder(file_con, file_size);
+bool wxGIFHandler_Write(wxOutputStream *stream, const void *buf, size_t len)
+{
+    return (len == stream->Write(buf, len).LastWrite());
+}

 
 

-    if (decod -> readgif(&igif) != E_OK) {
-        wxLogDebug("Error reading GIF");
-        free(file_con);
-        delete decod;
-        return FALSE;
-    }
-    free(file_con);
-    delete decod;
+bool wxGIFHandler_WriteByte(wxOutputStream *stream, wxUint8 byte)
+{
+    return wxGIFHandler_Write(stream, &byte, sizeof(byte));
+}
+
+bool wxGIFHandler_WriteWord(wxOutputStream *stream, wxUint16 word)
+{
+    wxUint8 buf[2];

 
 

-    image->Create(igif.w, igif.h);
-    if (!image->Ok()) {
-        free(igif.pal);
-        free(igif.p);
-        return FALSE;
+    buf[0] = word & 0xff;
+    buf[1] = (word >> 8) & 0xff;
+    return wxGIFHandler_Write(stream, &word, sizeof(word));
+}
+
+bool wxGIFHandler_WriteHeader(wxOutputStream *stream, int width, int height,
+    bool loop, const wxRGB *pal, int palCount, const wxString& comment)
+{
+    const int bpp = wxGIFHandler_BitSize(palCount);
+    wxUint8 buf[3];
+
+    bool ok = wxGIFHandler_Write(stream, GIF89_HDR, sizeof(GIF89_HDR)-1)
+        && wxGIFHandler_WriteWord(stream, (wxUint16) width)
+        && wxGIFHandler_WriteWord(stream, (wxUint16) height);
+
+    buf[0] = 0x80;
+    buf[0] |=(bpp - 1) << 5;
+    buf[0] |=(bpp - 1);
+    buf[1] = 0; // background color == entry 0
+    buf[2] = 0; // aspect ratio 1:1
+    ok = ok && wxGIFHandler_Write(stream, buf, sizeof(buf))
+        && wxGIFHandler_WritePalette(stream, pal, palCount, bpp);
+
+    if (loop)
+    {
+       ok = ok && wxGIFHandler_WriteLoop(stream);

     }
     }

-    image->SetMask(FALSE);

 
 

-    ptr = image->GetData();
-    src = igif.p;
-    pal = igif.pal;
-    for (i = 0; i < igif.w * igif.h; i++, src++) {
-        *(ptr++) = pal[3 * (*src) + 0];
-        *(ptr++) = pal[3 * (*src) + 1];
-        *(ptr++) = pal[3 * (*src) + 2];
+    if ( !comment.empty() )
+    {
+       ok = ok && wxGIFHandler_WriteComment(stream, comment);

     }
 
     }
 

-    free(igif.pal);
-    free(igif.p);
-    return TRUE;
+    return ok;

 }
 
 }
 

-bool wxGIFHandler::SaveFile( wxImage *image, wxOutputStream& stream )
+bool wxGIFHandler_WriteRect(wxOutputStream *stream, int width, int height)

 {
 {

-    wxLogDebug("wxGIFHandler is read-only!!");
-    return FALSE;
+    return wxGIFHandler_WriteWord(stream, 0) // left
+        && wxGIFHandler_WriteWord(stream, 0) // top
+        && wxGIFHandler_WriteWord(stream, (wxUint16) width)
+        && wxGIFHandler_WriteWord(stream, (wxUint16) height);

 }
 
 }
 

-//////////////////// Module:
+#if wxUSE_PALETTE
+bool wxGIFHandler_WriteTerm(wxOutputStream *stream)
+{
+    return wxGIFHandler_WriteByte(stream, GIF_MARKER_ENDOFDATA);
+}
+#endif

 
 

-/* We haven't yet decided to go for the wxModule approach or
- * explicit handler-adding: assuming the latter for now -- JACS
+bool wxGIFHandler_WriteZero(wxOutputStream *stream)
+{
+    return wxGIFHandler_WriteByte(stream, 0);
+}

 
 

-class wxGIFModule : public wxModule
+bool wxGIFHandler_WritePalette(wxOutputStream *stream,
+    const wxRGB *array, size_t count, int bpp)

 {
 {

-    DECLARE_DYNAMIC_CLASS(wxGIFModule)
+    wxUint8 buf[3];
+    for (int i = 0; (i < (1 << bpp)); i++)
+    {
+        if (i < (int)count)
+        {
+            buf[0] = array[i].red;
+            buf[1] = array[i].green;
+            buf[2] = array[i].blue;
+        }
+        else
+        {
+            buf[0] = buf[1] = buf[2] = 0;
+        }

 
 

-    public:
-        virtual bool OnInit()
+        if ( !wxGIFHandler_Write(stream, buf, sizeof(buf)) )

         {
         {

-            wxImage::AddHandler(new wxGIFHandler);
-            return TRUE;
+            return false;

         }
         }

-        virtual void OnExit() {}
-};
+    }
+
+    return true;
+}
+
+bool wxGIFHandler_WriteControl(wxOutputStream *stream,
+    int maskIndex, int delayMilliSecs)
+{
+    wxUint8 buf[8];
+
+    buf[0] = GIF_MARKER_EXT;    // extension marker
+    buf[1] = GIF_MARKER_EXT_GRAPHICS_CONTROL;
+    buf[2] = 4;     // length of block
+    buf[3] = (maskIndex != wxNOT_FOUND) ? 1 : 0;   // has transparency
+    buf[4] = delayMilliSecs / 10; // delay time
+    buf[5] = 0;
+    buf[6] = (maskIndex != wxNOT_FOUND) ? (wxUint8) maskIndex : 0;
+    buf[7] = 0;
+    return wxGIFHandler_Write(stream, buf, sizeof(buf));
+}
+
+bool wxGIFHandler_WriteComment(wxOutputStream *stream, const wxString& comment)
+{
+    wxUint8 buf[3];
+    wxCharBuffer text(comment.mb_str());
+    size_t len = strlen(text.data());
+    len = wxMin(len, 255);
+
+    buf[0] = GIF_MARKER_EXT;
+    buf[1] = GIF_MARKER_EXT_COMMENT;
+    buf[2] = (wxUint8)len;
+
+    return wxGIFHandler_Write(stream, buf, sizeof(buf))
+        && wxGIFHandler_Write(stream, text.data(), len)
+        && wxGIFHandler_WriteZero(stream);
+}
+
+bool wxGIFHandler_WriteLoop(wxOutputStream *stream)
+{
+    wxUint8 buf[4];
+    const int loopcount = 0; // infinite
+
+    buf[0] = GIF_MARKER_EXT;
+    buf[1] = GIF_MARKER_EXT_APP;
+    buf[2] = 0x0B;
+    bool ok = wxGIFHandler_Write(stream, buf, 3)
+        && wxGIFHandler_Write(stream, NETSCAPE_LOOP, sizeof(NETSCAPE_LOOP)-1);
+
+    buf[0] = 3;
+    buf[1] = 1;
+    buf[2] = loopcount & 0xFF;
+    buf[3] = loopcount >> 8;
+
+    return ok && wxGIFHandler_Write(stream, buf, 4)
+        && wxGIFHandler_WriteZero(stream);
+}

 
 

-IMPLEMENT_DYNAMIC_CLASS(wxGIFModule, wxModule)
+bool wxGIFHandler_BufferedOutput(wxOutputStream *stream, wxUint8 *buf, int c)
+{
+    bool ok = true;

 
 

-*/
+    if (c == FLUSH_OUTPUT)
+    {
+        // Flush everything out.
+        if (buf[0])
+        {
+            ok = wxGIFHandler_Write(stream, buf, buf[0]+1);
+        }
+        // Mark end of compressed data, by an empty block (see GIF doc):
+        wxGIFHandler_WriteZero(stream);
+    }
+    else
+    {
+        if (buf[0] == 255)
+        {
+            // Dump out this buffer - it is full:
+            ok = wxGIFHandler_Write(stream, buf, buf[0] + 1);
+            buf[0] = 0;
+        }
+        buf[++buf[0]] = c;
+    }
+
+    return ok;
+}

 
 

+#endif // wxUSE_STREAMS

 
 

+#endif  // wxUSE_IMAGE && wxUSE_GIF