mapnik/plugins/input/shape/dbfile.cpp
2021-01-05 14:39:07 +00:00

281 lines
7.2 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2021 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
*
*****************************************************************************/
// mapnik
#include <mapnik/value/types.hpp>
#include <mapnik/global.hpp>
#include <mapnik/util/utf_conv_win.hpp>
#include <mapnik/unicode.hpp>
#include <mapnik/util/trim.hpp>
#include "dbfile.hpp"
#include <mapnik/warning.hpp>
MAPNIK_DISABLE_WARNING_PUSH
#include <mapnik/warning_ignore.hpp>
#include <boost/spirit/home/x3.hpp>
#if defined(MAPNIK_MEMORY_MAPPED_FILE)
#include <boost/interprocess/mapped_region.hpp>
#include <mapnik/mapped_memory_cache.hpp>
#endif
MAPNIK_DISABLE_WARNING_POP
// stl
#include <cstdint>
#include <string>
#include <cstring>
#include <stdexcept>
dbf_file::dbf_file()
: num_records_(0),
num_fields_(0),
record_length_(0),
record_(0) {}
dbf_file::dbf_file(std::string const& file_name)
:num_records_(0),
num_fields_(0),
record_length_(0),
#if defined(MAPNIK_MEMORY_MAPPED_FILE)
file_(),
#elif defined(_WINDOWS)
file_(mapnik::utf8_to_utf16(file_name), std::ios::in | std::ios::binary),
#else
file_(file_name.c_str() ,std::ios::in | std::ios::binary),
#endif
record_(0)
{
#if defined(MAPNIK_MEMORY_MAPPED_FILE)
boost::optional<mapnik::mapped_region_ptr> memory = mapnik::mapped_memory_cache::instance().find(file_name,true);
if (memory)
{
mapped_region_ = *memory;
file_.buffer(static_cast<char*>((*memory)->get_address()),(*memory)->get_size());
}
else
{
throw std::runtime_error("could not create file mapping for "+file_name);
}
#endif
if (file_)
{
read_header();
}
}
dbf_file::~dbf_file()
{
::operator delete(record_);
}
bool dbf_file::is_open()
{
#if defined(MAPNIK_MEMORY_MAPPED_FILE)
return (file_.buffer().second > 0);
#else
return file_.is_open();
#endif
}
int dbf_file::num_records() const
{
return num_records_;
}
int dbf_file::num_fields() const
{
return num_fields_;
}
void dbf_file::move_to(int index)
{
if (index>0 && index<=num_records_)
{
std::streampos pos=(num_fields_<<5)+34+(index-1)*(record_length_+1);
file_.seekg(pos,std::ios::beg);
file_.read(record_,record_length_);
}
}
std::string dbf_file::string_value(int col) const
{
if (col>=0 && col<num_fields_)
{
return std::string(record_+fields_[col].offset_,fields_[col].length_);
}
return "";
}
const field_descriptor& dbf_file::descriptor(int col) const
{
assert(col>=0 && col<num_fields_);
return fields_[col];
}
void dbf_file::add_attribute(int col, mapnik::transcoder const& tr, mapnik::feature_impl & f) const
{
using namespace boost::spirit;
if (col>=0 && col<num_fields_)
{
std::string const& name=fields_[col].name_;
// NOTE: ensure types handled here are matched in shape_datasource.cpp
switch (fields_[col].type_)
{
case 'C':
case 'D':
{
// FIXME - avoid constructing std::string on stack
std::string str(record_+fields_[col].offset_,fields_[col].length_);
mapnik::util::trim(str);
f.put(name,tr.transcode(str.c_str()));
break;
}
case 'L':
{
char ch = record_[fields_[col].offset_];
if ( ch == '1' || ch == 't' || ch == 'T' || ch == 'y' || ch == 'Y')
{
f.put(name,true);
}
else
{
// NOTE: null logical fields use '?'
f.put(name,false);
}
break;
}
case 'N': // numeric
case 'O': // double
case 'F': // float
{
if (record_[fields_[col].offset_] == '*')
{
// NOTE: we intentionally do not store null here
// since it is equivalent to the attribute not existing
break;
}
if ( fields_[col].dec_>0 )
{
double val = 0.0;
const char *itr = record_+fields_[col].offset_;
const char *end = itr + fields_[col].length_;
x3::ascii::space_type space;
static x3::double_type double_;
if (x3::phrase_parse(itr,end,double_,space,val))
{
f.put(name,val);
}
}
else
{
mapnik::value_integer val = 0;
const char *itr = record_+fields_[col].offset_;
const char *end = itr + fields_[col].length_;
x3::ascii::space_type space;
static x3::int_parser<mapnik::value_integer,10,1,-1> numeric_parser;
if (x3::phrase_parse(itr, end, numeric_parser, space, val))
{
f.put(name,val);
}
}
break;
}
}
}
}
void dbf_file::read_header()
{
char c=file_.get();
if (c=='\3' || c=='\131')
{
skip(3);
num_records_=read_int();
assert(num_records_>=0);
num_fields_=read_short();
assert(num_fields_>0);
num_fields_=(num_fields_-33)/32;
skip(22);
std::streampos offset=0;
char name[11];
std::memset(&name,0,11);
fields_.reserve(num_fields_);
for (int i=0;i<num_fields_;++i)
{
field_descriptor desc;
desc.index_=i;
file_.read(name,10);
desc.name_=name;
// TODO - when is this trim needed?
mapnik::util::trim(desc.name_);
skip(1);
desc.type_=file_.get();
skip(4);
desc.length_=file_.get();
desc.dec_=file_.get();
skip(14);
desc.offset_=offset;
offset+=desc.length_;
fields_.push_back(desc);
}
record_length_=offset;
if (record_length_>0)
{
record_=static_cast<char*>(::operator new (sizeof(char)*record_length_));
}
}
}
int dbf_file::read_short()
{
char b[2];
file_.read(b,2);
std::int16_t val;
mapnik::read_int16_ndr(b,val);
return val;
}
int dbf_file::read_int()
{
char b[4];
file_.read(b,4);
std::int32_t val;
mapnik::read_int32_ndr(b,val);
return val;
}
void dbf_file::skip(int bytes)
{
file_.seekg(bytes,std::ios::cur);
}