// gifimage.cpp -- image data from gif file
//
// Written by Frederic Bouvier, started November 2004.
//
// Copyright (C) 2004  Frederic Bouvier - fredb@users.sourceforge.net
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id: gifimage.cpp,v 1.2 2005/05/09 07:01:52 fredb Exp $

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#ifdef HAVE_GIF_LIB_H
#include "gifimage.hpp"
#include <string.h>
#include <stdio.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fstream>

extern "C" {
#  include "gif_lib.h"
}

FGSD_GIFImage::FGSD_GIFImage( bool __reverted )
   :  _reverted( __reverted )
{
}

FGSD_GIFImage::~FGSD_GIFImage ()
{
}

bool FGSD_GIFImage::load (const char *__fileName)
{
   bool ret = false;
   GifFileType *gif = DGifOpenFileName( __fileName );

   if ( gif != 0 ) {
      int res = DGifSlurp( gif );
      if ( res == GIF_OK && gif->ImageCount >= 1 ) {
         SavedImage *image = gif->SavedImages;

         allocImage( gif->SWidth, gif->SHeight );

         for ( int i = 0; i < gif->SHeight; i++ ) {
            int r = _reverted ? gif->SHeight - ( i + 1 ) : i;
            unsigned char *buf = buffer( r );
            for ( int j = 0; j < gif->SWidth; j++ ) {
               char index = image->RasterBits[ i * gif->SWidth + j ];
               GifByteType red = 0;
               GifByteType green = 0;
               GifByteType blue = 0;
               if ( index < gif->SColorMap->ColorCount ) {
                  red = gif->SColorMap->Colors[ index ].Red;
                  green = gif->SColorMap->Colors[ index ].Green;
                  blue = gif->SColorMap->Colors[ index ].Blue;
               }
               buf[ j * 3 + 0 ] = red;
               buf[ j * 3 + 1 ] = green;
               buf[ j * 3 + 2 ] = blue;
            }
         }

         ret = true;
      }

      DGifCloseFile( gif );
   }

   return ret;
}

int FGSD_GIFImage::readData_cb(void *g,unsigned char* b,int l)
{
#ifdef HAVE_DGIFOPEN
   GifFileType *gif = static_cast<GifFileType *>( g );
   return static_cast<FGSD_GIFImage *>( gif->UserData )->readData( b, l );
#else
   return 0;
#endif
}

int FGSD_GIFImage::readData(unsigned char *b,int l)
{
   int nb = l;
   if ( nb + _sent > (int)_len ) {
      nb = _len - _sent;
   }
   ::memcpy( b, _buffer + _sent, nb );
   _sent += nb;

   return nb;
}

bool FGSD_GIFImage::loadFromBuffer( const unsigned char *__buffer, size_t __len )
{
   bool ret = false;
#ifdef HAVE_DGIFOPEN
   _sent = 0;
   _buffer = __buffer;
   _len = __len;
   GifFileType *gif = DGifOpen(this,(InputFunc)readData_cb);
#else
#ifdef HAVE_MKSTEMP
   char *templ = 0;
   char *tmp = getenv("TMP");
   if ( tmp == 0 ) {
      templ = new char[ 17 ];
      strcpy( templ, "/tmp/fgsd$XXXXXX" );
   } else {
      templ = new char[ strlen( tmp ) + 13 ];
      strcpy( templ, tmp );
      strcat( templ, "/fgsd$XXXXXX" );
   }
   int fd = mkstemp( templ );
   if ( fd == -1 ) {
      delete[] templ;
      return false;
   }
   write( fd, (char *)__buffer, __len );
   lseek( fd, 0, SEEK_SET );
   GifFileType *gif = DGifOpenFileHandle( fd );
#else
   char *fn = tempnam( 0, "fgsd$" );
   if ( fn ) {
      std::ofstream fstr( fn, std::ios::trunc | std::ios::binary );
      fstr.write( (char *)__buffer, __len );
   }
   GifFileType *gif = DGifOpenFileName( fn );
#endif
#endif

   if ( gif != 0 ) {
      int res = DGifSlurp( gif );
      if ( res == GIF_OK && gif->ImageCount >= 1 ) {
         SavedImage *image = gif->SavedImages;

         allocImage( gif->SWidth, gif->SHeight );

         for ( int i = 0; i < gif->SHeight; i++ ) {
            int r = _reverted ? gif->SHeight - ( i + 1 ) : i;
            unsigned char *buf = buffer( r );
            for ( int j = 0; j < gif->SWidth; j++ ) {
               char index = image->RasterBits[ i * gif->SWidth + j ];
               GifByteType red = 0;
               GifByteType green = 0;
               GifByteType blue = 0;
               if ( index < gif->SColorMap->ColorCount ) {
                  red = gif->SColorMap->Colors[ index ].Red;
                  green = gif->SColorMap->Colors[ index ].Green;
                  blue = gif->SColorMap->Colors[ index ].Blue;
               }
               buf[ j * 3 + 0 ] = red;
               buf[ j * 3 + 1 ] = green;
               buf[ j * 3 + 2 ] = blue;
            }
         }

         ret = true;
      }

      DGifCloseFile( gif );
   }

#ifndef HAVE_DGIFOPEN
#ifdef HAVE_MKSTEMP
   close( fd );
   unlink( templ );
   delete[] templ;
#else
   unlink( fn );
#endif
#endif

   return ret;
}
#endif