mapnik/src/image_cache.cpp
2010-06-02 11:03:30 +00:00

99 lines
3 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2009 Artem Pavlenko
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
//$Id$
// mapnik
#include <mapnik/image_cache.hpp>
#include <mapnik/image_reader.hpp>
// boost
#include <boost/assert.hpp>
#include <boost/filesystem/operations.hpp>
#include <boost/algorithm/string.hpp>
namespace mapnik
{
boost::unordered_map<std::string, image_ptr> image_cache::cache_;
bool image_cache::insert (std::string const& uri, image_ptr img)
{
#ifdef MAPNIK_THREADSAFE
mutex::scoped_lock lock(mutex_);
#endif
return cache_.insert(std::make_pair(uri,img)).second;
}
boost::optional<image_ptr> image_cache::find(std::string const& uri, bool update_cache)
{
#ifdef MAPNIK_THREADSAFE
mutex::scoped_lock lock(mutex_);
#endif
typedef boost::unordered_map<std::string, image_ptr>::const_iterator iterator_type;
boost::optional<image_ptr> result;
iterator_type itr = cache_.find(uri);
if (itr != cache_.end())
{
result.reset(itr->second);
return result;
}
// we can't find image in cache, lets try to load it from filesystem
boost::filesystem::path path(uri);
if (exists(path))
{
try
{
std::auto_ptr<mapnik::image_reader> reader(mapnik::get_image_reader(uri));
if (reader.get())
{
unsigned width = reader->width();
unsigned height = reader->height();
BOOST_ASSERT(width > 0 && height > 0);
mapnik::image_ptr image(new mapnik::image_data_32(width,height));
reader->read(0,0,*image);
result.reset(image);
if (update_cache)
{
cache_.insert(std::make_pair(uri,image));
}
}
}
catch (...)
{
std::cerr << "Exception caught while loading image: " << uri << std::endl;
}
}
else
{
std::cerr << "### WARNING image does not exist: " << uri << std::endl;
}
return result;
}
#ifdef MAPNIK_THREADSAFE
boost::mutex image_cache::mutex_;
#endif
}