mapnik/plugins/input/shape/dbfile.cpp
2024-07-22 10:20:47 +01:00

237 lines
6.7 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2024 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)
: mapped_memory_file{file_name}
, num_records_(0)
, num_fields_(0)
, record_length_(0)
, record_(0)
{
if (file_)
{
read_header();
}
}
dbf_file::~dbf_file()
{
::operator delete(record_);
}
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;
}