Replace code_elements in epsg with statically sized type for faster c…

…ompile times and replace binary search with perfect hashing.

include/boost/geometry/srs/projections/code.hpp

@@ -10,42 +10,154 @@
 #ifndef BOOST_GEOMETRY_PROJECTIONS_CODE_HPP
 #define BOOST_GEOMETRY_PROJECTIONS_CODE_HPP
 
-
-#include <algorithm>
+#include <cstdint>
 
 #include <boost/geometry/srs/projections/dpar.hpp>
 
-
 namespace boost { namespace geometry { namespace projections
 {
 
-
 #ifndef DOXYGEN_NO_DETAIL
 namespace detail
 {
 
+ template <std::size_t MaxParams, bool HasTowgs84 = true>
  struct code_element
  {
+ union parameter_variant
+ {
+ bool b;
+ int i;
+ double v;
+ //spheroid
+ //nadgrids,
+ //towgs84
+ };
+
  int code;
- srs::dpar::parameters<> parameters;
+ std::int8_t parameter_count;
+ std::int8_t towgs84_size {0};
+ // Not bundling the following together into a struct to avoid 8-byte-alignment.
+ std::int8_t parameter_variant_tags[MaxParams];
+ std::int16_t parameter_ids[MaxParams];
+ parameter_variant parameters[MaxParams];
+ double towgs84_data[7];
  };
 
- struct code_element_less
+ template <std::size_t MaxParams>
+ struct code_element<MaxParams, false>
  {
- inline bool operator()(code_element const& l, code_element const& r) const
+ union parameter_variant
  {
- return l.code < r.code;
+ bool b;
+ int i;
+ double v;
+ };
+
+ int code;
+ std::int8_t parameter_count;
+ std::int8_t parameter_variant_tags[MaxParams];
+ std::int16_t parameter_ids[MaxParams];
+ parameter_variant parameters[MaxParams];
+ };
+
+ template <bool HasTowgs84 = true>
+ struct code_element_to_towgs84
+ {
+ template <std::size_t MaxParams>
+ static void apply(code_element<MaxParams, true> const& e,
+ srs::dpar::parameters<double>& out)
+ {
+ using p = srs::dpar::parameter<double>;
+ out(p(srs::dpar::name_towgs84::towgs84,
+ srs::detail::towgs84<double>(e.towgs84_data, e.towgs84_data + e.towgs84_size)));
  }
  };
 
- template<typename RandIt>
- inline RandIt binary_find_code_element(RandIt first, RandIt last, int code)
+ template <>
+ struct code_element_to_towgs84<false>
+ {
+ template <std::size_t MaxParams>
+ static void apply(code_element<MaxParams, false> const&, srs::dpar::parameters<double>&) {}
+ };
+
+
+ template <std::size_t MaxParams, bool HasTowgs84>
+ inline srs::dpar::parameters<>
+ code_element_to_dpar_parameters(code_element<MaxParams, HasTowgs84> const& e)
  {
- code_element_less comp;
- code_element value;
- value.code = code;
- first = std::lower_bound(first, last, value, comp);
- return first != last && !comp(value, *first) ? first : last;
+ using namespace srs::dpar;
+ using p = srs::dpar::parameter<double>;
+ srs::dpar::parameters<> out;
+ out.reserve(e.parameter_count);
+ for (int i = 0; i < e.parameter_count; ++i)
+ {
+ auto const& id = e.parameter_ids[i];
+ auto const& pv = e.parameters[i];
+ auto const& tag = e.parameter_variant_tags[i];
+ if (id == -1)
+ {
+ out(p());
+ }
+ else if (id < static_cast<int>(name_r::alpha)) // f
+ {
+ out(p(static_cast<name_f>(id), pv.v));
+ }
+ else if (id < static_cast<int>(name_i::aperture)) // r
+ {
+ out(p(static_cast<name_r>(id), pv.v));
+ }
+ else if (id < static_cast<int>(name_be::czech)) // i
+ {
+ out(p(static_cast<name_i>(id), pv.i));
+ }
+ else if (id < static_cast<int>(name_datum::datum)) // be
+ {
+ out(p(static_cast<name_be>(id), pv.b));
+ }
+ else if (id == static_cast<int>(name_datum::datum)) //datum
+ {
+ out(p(name_datum::datum, static_cast<value_datum>(pv.i)));
+ }
+ else if ( id == static_cast<int>(name_ellps::ellps)) //ellps
+ {
+ out(p(name_ellps::ellps, static_cast<value_ellps>(pv.i)));
+ }
+ // no occurence of ellps with spheroid in arr
+ // no occurence of mode in arr
+ // no occurence of nadgrids in arr
+ // no occurence of orient in arr
+ else if (id == static_cast<name_pm>(name_pm::pm)) //pm
+ {
+ if (tag == 1)
+ {
+ out(p(name_pm::pm, static_cast<value_pm>(pv.i)));
+ }
+ else //if tag == 2
+ {
+ out(p(name_pm::pm, pv.v));
+ }
+ }
+ else if (id < static_cast<int>(name_sweep::sweep)) // proj
+ {
+ out(p(static_cast<name_proj>(id), static_cast<value_proj>(pv.i)));
+ }
+ else if (id == static_cast<int>(name_sweep::sweep)) // sweep
+ {
+ out(p(name_sweep::sweep, static_cast<value_sweep>(pv.i)));
+ }
+ else if (id == static_cast<int>(name_towgs84::towgs84)) //towgs84
+ {
+ code_element_to_towgs84<HasTowgs84>::apply(e, out);
+ }
+ // no occurence of axis in arr
+ else if (id == static_cast<int>(name_units::units)) //units
+ {
+ out(p(name_units::units, static_cast<value_units>(pv.i)));
+ }
+ // no occurence of vunits in arr
+ }
+ return out;
  }
 
 }

include/boost/geometry/srs/projections/dpar.hpp

@@ -722,8 +722,11 @@ struct parameter
  {
  return m_value.which() == srs::detail::find_type_index<variant_type, V>::value;
  }
-
+#if defined(BOOST_GEOMETRY_ENABLE_SRS_PARAMETER_DEBUGGING)
+public:
+#else
 private:
+#endif
  int m_id;
  variant_type m_value;
 };
@@ -801,8 +804,9 @@ class parameters
  const_iterator begin() const { return m_params.begin(); }
  const_iterator end() const { return m_params.end(); }
  const_reference operator[](size_type i) const { return m_params[i]; }
- size_type size() { return m_params.size(); }
- bool empty() { return m_params.empty(); }
+ size_type size() const { return m_params.size(); }
+ bool empty() const { return m_params.empty(); }
+ void reserve(std::size_t s) { m_params.reserve(s); }
 
 private:
  container_type m_params;