Implement CanRead

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

/////////////////////////////////////////////////////////////////////////////
// Name:        imaggif.cpp
// Purpose:     wxGIFHandler
// Author:      Vaclav Slavik
//              Based on wxGIFDecoder by Guillermo Rodriguez Garcia
// RCS-ID:      $Id$
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

/*
We don't put pragma implement in this file because it is already present in
src/common/image.cpp
*/

// For compilers that support precompilation, includes "wx.h".
#include <wx/wxprec.h>

#ifdef __BORLANDC__
#  pragma hdrstop
#endif

#ifndef WX_PRECOMP
#  include "wx/defs.h"
#endif

#include "wx/image.h"
// #include "wx/imaggif.h"
#include "wx/gifdecod.h"
#include "wx/wfstream.h"
#include "wx/module.h"
#include "wx/log.h"

IMPLEMENT_DYNAMIC_CLASS(wxGIFHandler,wxImageHandler)

#if wxUSE_STREAMS

//-----------------------------------------------------------------------------
// wxGIFHandler
//-----------------------------------------------------------------------------

bool wxGIFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool WXUNUSED(verbose) )
{
    wxGIFDecoder *decod;
    bool ok;

    decod = new wxGIFDecoder(&stream, TRUE);
    
    if (decod->ReadGIF() != E_OK)
    {
        wxLogDebug(_T("Error reading GIF"));
        delete decod;
        return FALSE;
    }

    image->Destroy();
    ok = decod->ConvertToImage(image);

    delete decod;
    return ok;
}

bool wxGIFHandler::SaveFile( wxImage * WXUNUSED(image),
                             wxOutputStream& WXUNUSED(stream), bool verbose )
{
    if (verbose) wxLogDebug(_T("wxGIFHandler is read-only!!"));
    return FALSE;
}

bool wxGIFHandler::CanRead( wxInputStream& stream )
{
    unsigned char hdr[5];
    
    stream.Read(&hdr, 5);
    stream.SeekI(-5, wxFromCurrent);
    return (hdr[0] == 'G' && hdr[1] == 'I' && hdr[2] == 'F' && hdr[3] == '8' && hdr[4] == '9');
}

#endif