mapnik/plugins/input/shape/shapefile.hpp

/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2006 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: shapefile.hpp 33 2005-04-04 13:01:03Z pavlenko $

#ifndef SHAPEFILE_HPP
#define SHAPEFILE_HPP

#include <mapnik/global.hpp>
#include <mapnik/envelope.hpp>
// boost
#include <boost/utility.hpp>
#include <boost/cstdint.hpp>
#include <boost/iostreams/stream.hpp>

#include <boost/iostreams/device/file.hpp>
#include <boost/iostreams/device/mapped_file.hpp>

#include <cstring>

using mapnik::Envelope;
using mapnik::read_int32_ndr;
using mapnik::read_int32_xdr;
using mapnik::read_double_ndr;
using mapnik::read_double_xdr;


struct RecordTag
{
    typedef char* data_type;
    static data_type alloc(unsigned size)
    {
        return static_cast<data_type>(::operator new(sizeof(char)*size));
    }
    
    static void dealloc(data_type data)
    {
        ::operator delete(data);
    }
};

struct MappedRecordTag
{
    typedef const char* data_type;
    static data_type alloc(unsigned) { return 0;}
    static void dealloc(data_type ) {}
};

template <typename Tag>
struct shape_record
{
    typename Tag::data_type data;
    size_t size;
    mutable size_t pos;
    explicit shape_record(size_t size)
	: 
        data(Tag::alloc(size)),
        size(size),
        pos(0) {} 
      
    void set_data(typename Tag::data_type data_)
    {
        data = data_;
    }

    typename Tag::data_type get_data() 
    {
        return data; 
    }
    
    void skip(unsigned n)
    {
        pos+=n;
    }
      
    int read_ndr_integer()
    {
        int val;
        read_int32_ndr(&data[pos],val);
        pos+=4;
        return val;
    }
      
    int read_xdr_integer()
    {
        int val;
        read_int32_xdr(&data[pos],val);
        pos+=4;
        return val;
    }
      
    double read_double()
    {
        double val;		
        read_double_ndr(&data[pos],val);
        pos+=8;
        return val;
    }
    long remains() 
    {
        return (size-pos);
    }
  
    ~shape_record() 
    {
        Tag::dealloc(data);
    }
 
};

using namespace boost::iostreams;

class shape_file : boost::noncopyable
{  
#ifdef SHAPE_MEMORY_MAPPED_FILE
    stream<mapped_file_source> file_;
#else
    stream<file_source> file_;
#endif
    
public:
#ifdef SHAPE_MEMORY_MAPPED_FILE
    typedef shape_record<MappedRecordTag> record_type;
#else
    typedef shape_record<RecordTag> record_type;
#endif
    
    shape_file() {}

    shape_file(std::string  const& file_name)
        : file_(file_name) {}

    ~shape_file() {}

    inline bool is_open()
    {
        return file_.is_open();
    }


    inline void close()
    {
        if (file_ && file_.is_open())
            file_.close();
    }
    
    inline void read_record(record_type& rec)
    {
#ifdef SHAPE_MEMORY_MAPPED_FILE
	rec.set_data(file_->data() + file_.tellg());
	file_.seekg(rec.size,std::ios::cur);
#else
        file_.read(rec.get_data(),rec.size);
#endif
    }
    
    inline int read_xdr_integer()
    {
        char b[4];
        file_.read(b, 4);
        int val;
        read_int32_xdr(b,val);
        return val;
    }
      
    inline int read_ndr_integer()
    {
        char b[4];
        file_.read(b,4);
        int val;
        read_int32_ndr(b,val);
        return val;
    }
      
    inline double read_double()
    {
        double val;
#ifndef MAPNIK_BIG_ENDIAN
        file_.read(reinterpret_cast<char*>(&val),8);
#else
        char b[8];
        file_.read(b,8);
        read_double_ndr(b,val);
#endif
        return val;
    }
    
    inline void read_envelope(Envelope<double>& envelope)
    {
#ifndef MAPNIK_BIG_ENDIAN
        file_.read(reinterpret_cast<char*>(&envelope),sizeof(envelope));
#else
        char data[4*8];
        file_.read(data,4*8);
        double minx,miny,maxx,maxy;
        read_double_ndr(data + 0*8,minx);
        read_double_ndr(data + 1*8,miny);
        read_double_ndr(data + 2*8,maxx);
        read_double_ndr(data + 3*8,maxy);
        envelope.init(minx,miny,maxx,maxy);
#endif  
    }
      
    inline void skip(std::streampos bytes)
    {
        file_.seekg(bytes,std::ios::cur);
    }
      
    inline void rewind()
    {
        seek(100);
    }
      
    inline void seek(std::streampos pos)
    {
        file_.seekg(pos,std::ios::beg);
    }
      
    inline std::streampos pos()
    {
        return file_.tellg();
    }
      
    inline bool is_eof()
    {
        return file_.eof();
    }
};

#endif //SHAPEFILE_HPP