refactor height filter to appease cppcheck & MSVC (GPSBabel#473)

* refactor heightgrid to appease cppcheck.

With newer versions (somwhere after 1.82) of cppcheck analyzing
height.cc took an excessive amount of time.
By making these variables private static class members instead of
member function static variables we avoid the cppcheck issues.

* tweak height to work around MSVC 2017 error.

and hopefully MSVC 2015 error as well.

* don't include cstdint within class definition.

It can lead to compile failures.  This was done in heightgrid.h,
but the include guards in cstdint hid the error.

.codacy.yaml

@@ -5,7 +5,6 @@ exclude_paths:
   - 'shapelib/**'
   - 'zlib/**'
   - coverity_model.cc
-  - height.cc # It takes newer cppcheck versions, somewhere > 1.82, an excessive amount of time to analyze heightgrid.h
   - strptime.[ch]
   - jeeps/gpsproj.cc
   - jeeps/gpsproj.h

height.cc

@@ -24,13 +24,23 @@
 
 #include "defs.h"
 #include "height.h"
-#include <cmath>
-#include <cstdlib>
+#include <cmath>    // for floor
+#include <cstdint>  // for int8_t
+#include <cstdlib>  // for strtod
 
 #define MYNAME "height"
 
 #if FILTERS_ENABLED
 
+// Until c++17 we have to define odr-used constexpr static data members at namespace scope.
+#if __cplusplus < 201703L
+constexpr double HeightFilter::geoid_grid_deg;
+constexpr double HeightFilter::geoid_scale;
+constexpr int HeightFilter::geoid_row;
+constexpr int HeightFilter::geoid_col;
+constexpr int8_t HeightFilter::geoid_delta[geoid_row][geoid_col];
+#endif
+
 double HeightFilter::bilinear(double x1, double y1, double x2, double y2, double x, double y, double z11, double z12, double z21, double z22)
 {
   if (y1 == y2 && x1 == x2) {
@@ -51,9 +61,6 @@ double HeightFilter::bilinear(double x1, double y1, double x2, double y2, double
 /* return geoid separation (MSL - WGS84) in meters, given a lat/lot in degrees */
 double HeightFilter::wgs84_separation(double lat, double lon)
 {
-#include "heightgrid.h"
-
-
   /* sanity checks to prevent segfault on bad data */
   if ((lat > 90.0) || (lat < -90.0)) {
     fatal(MYNAME ": Invalid latitude value (%f)\n", lat);
@@ -62,35 +69,35 @@ double HeightFilter::wgs84_separation(double lat, double lon)
     fatal(MYNAME ": Invalid longitude value (%f)\n", lon);
   }
 
-  int ilat = (int)floor((90.0+lat)/GEOID_GRID_DEG);
-  int ilon = (int)floor((180.0+lon)/GEOID_GRID_DEG);
+  auto ilat = static_cast<int>(floor((90.0+lat)/geoid_grid_deg));
+  auto ilon = static_cast<int>(floor((180.0+lon)/geoid_grid_deg));
 
   int ilat1 = ilat;
   int ilon1 = ilon;
-  int ilat2 = (ilat < GEOID_ROW-1)? ilat+1:ilat;
-  int ilon2 = (ilon < GEOID_COL-1)? ilon+1:ilon;
+  int ilat2 = (ilat < geoid_row-1)? ilat+1:ilat;
+  int ilon2 = (ilon < geoid_col-1)? ilon+1:ilon;
 
   return bilinear(
-           ilon1*GEOID_GRID_DEG-180.0,ilat1*GEOID_GRID_DEG-90.0,
-           ilon2*GEOID_GRID_DEG-180.0,ilat2*GEOID_GRID_DEG-90.0,
+           ilon1*geoid_grid_deg-180.0, ilat1*geoid_grid_deg-90.0,
+           ilon2*geoid_grid_deg-180.0, ilat2*geoid_grid_deg-90.0,
            lon, lat,
-           (double)geoid_delta[ilon1+ilat1*GEOID_COL]/GEOID_SCALE,
-           (double)geoid_delta[ilon2+ilat1*GEOID_COL]/GEOID_SCALE,
-           (double)geoid_delta[ilon1+ilat2*GEOID_COL]/GEOID_SCALE,
-           (double)geoid_delta[ilon2+ilat2*GEOID_COL]/GEOID_SCALE
+           static_cast<double>(geoid_delta[ilat1][ilon1])/geoid_scale,
+           static_cast<double>(geoid_delta[ilat1][ilon2])/geoid_scale,
+           static_cast<double>(geoid_delta[ilat2][ilon1])/geoid_scale,
+           static_cast<double>(geoid_delta[ilat2][ilon2])/geoid_scale
          );
 }
 
 void HeightFilter::correct_height(const Waypoint* wpt)
 {
-  Waypoint* waypointp = const_cast<Waypoint*>(wpt);
+  auto* waypointp = const_cast<Waypoint*>(wpt);
 
   if (waypointp->altitude != unknown_alt) {
-    if (addopt) {
+    if (addopt != nullptr) {
       waypointp->altitude += addf;
     }
 
-    if (wgs84tomslopt) {
+    if (wgs84tomslopt != nullptr) {
       waypointp->altitude -= wgs84_separation(waypointp->latitude, waypointp->longitude);
     }
   }
@@ -100,7 +107,7 @@ void HeightFilter::init()
 {
   char* unit;
 
-  if (addopt) {
+  if (addopt != nullptr) {
     addf = strtod(addopt, &unit);
 
     if (*unit == 'f' || *unit== 'F') {

height.h

@@ -24,10 +24,12 @@
 #ifndef HEIGHT_H_INCLUDED_
 #define HEIGHT_H_INCLUDED_
 
+#include <cstdint>         // for int8_t in heightgrid.h
+
 #include <QtCore/QVector>  // for QVector
 
-#include "defs.h"    // for ARG_NOMINMAX, Waypoint (ptr only), arglist_t
-#include "filter.h"  // for Filter
+#include "defs.h"          // for arglist_t, ARG_NOMINMAX, ARGTYPE_BEGIN_REQ, ARGTYPE_BOOL, ARGTYPE_END_REQ, ARGTYPE_FLOAT, Waypoint
+#include "filter.h"        // for Filter
 
 #if FILTERS_ENABLED
 
@@ -45,6 +47,8 @@ class HeightFilter:public Filter
   char* addopt        = nullptr;
   char* wgs84tomslopt = nullptr;
   double addf;
+  // include static constexpr data member definitions with intializers for grid as private members.
+  #include "heightgrid.h"
 
   QVector<arglist_t> args = {
     {