Implement RFC 2: Initial integration of "GDAL SRS barn" work

This work mostly consists of:
- a C++ implementation of the ISO-19111:2018 / OGC Topic 2
  "Referencing by coordinates" classes to represent Datums,
  Coordinate systems, CRSs (Coordinate Reference Systems) and
  Coordinate Operations.
- methods to convert between this C++ modeling and WKT1, WKT2
  and PROJ string representations of those objects
- management and query of a SQLite3 database of CRS and Coordinate Operation definition
- a C API binding part of those capabilities

This is all-in-one squashed commit of the work of
https://github.com/OSGeo/proj.4/pull/1040

1 files changed, 163 insertions, 0 deletions

diff --git a/include/proj/internal/io_internal.hpp b/include/proj/internal/io_internal.hpp
new file mode 100644
index 00000000..8a32c6eb
--- /dev/null
+++ b/include/proj/internal/io_internal.hpp
@@ -0,0 +1,163 @@
+/******************************************************************************
+ *
+ * Project:  PROJ
+ * Purpose:  ISO19111:2018 implementation
+ * Author:   Even Rouault <even dot rouault at spatialys dot com>
+ *
+ ******************************************************************************
+ * Copyright (c) 2018, Even Rouault <even dot rouault at spatialys dot com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ ****************************************************************************/
+
+#ifndef FROM_PROJ_CPP
+#error This file should only be included from a PROJ cpp file
+#endif
+
+#ifndef IO_INTERNAL_HH_INCLUDED
+#define IO_INTERNAL_HH_INCLUDED
+
+#include <string>
+#include <vector>
+
+#include "proj/util.hpp"
+
+//! @cond Doxygen_Suppress
+
+NS_PROJ_START
+
+namespace io {
+
+// ---------------------------------------------------------------------------
+
+class WKTConstants {
+  public:
+    // WKT1
+    static const std::string GEOCCS;
+    static const std::string GEOGCS;
+    static const std::string DATUM; // WKT2 preferred too
+    static const std::string UNIT;
+    static const std::string SPHEROID;
+    static const std::string AXIS;   // WKT2 too
+    static const std::string PRIMEM; // WKT2 too
+    static const std::string AUTHORITY;
+    static const std::string PROJCS;
+    static const std::string PROJECTION;
+    static const std::string PARAMETER; // WKT2 too
+    static const std::string VERT_CS;
+    static const std::string VERT_DATUM;
+    static const std::string COMPD_CS;
+    static const std::string TOWGS84;     // WKT1 only
+    static const std::string EXTENSION;   // WKT1 only - GDAL specific
+    static const std::string LOCAL_CS;    // WKT1 only
+    static const std::string LOCAL_DATUM; // WKT1 only
+
+    // WKT2 preferred
+    static const std::string GEODCRS;
+    static const std::string LENGTHUNIT;
+    static const std::string ANGLEUNIT;
+    static const std::string SCALEUNIT;
+    static const std::string TIMEUNIT;
+    static const std::string ELLIPSOID;
+    static const std::string CS;
+    static const std::string ID;
+    static const std::string PROJCRS;
+    static const std::string BASEGEODCRS;
+    static const std::string MERIDIAN;
+    static const std::string ORDER;
+    static const std::string ANCHOR;
+    static const std::string CONVERSION;
+    static const std::string METHOD;
+    static const std::string REMARK;
+    static const std::string GEOGCRS;     // WKT2-2018
+    static const std::string BASEGEOGCRS; // WKT2-2018
+    static const std::string SCOPE;
+    static const std::string AREA;
+    static const std::string BBOX;
+    static const std::string CITATION;
+    static const std::string URI;
+    static const std::string VERTCRS;
+    static const std::string VDATUM;
+    static const std::string COMPOUNDCRS;
+    static const std::string PARAMETERFILE;
+    static const std::string COORDINATEOPERATION;
+    static const std::string SOURCECRS;
+    static const std::string TARGETCRS;
+    static const std::string INTERPOLATIONCRS;
+    static const std::string OPERATIONACCURACY;
+    static const std::string CONCATENATEDOPERATION; // WKT2-2018
+    static const std::string STEP;                  // WKT2-2018
+    static const std::string BOUNDCRS;
+    static const std::string ABRIDGEDTRANSFORMATION;
+    static const std::string DERIVINGCONVERSION;
+    static const std::string TDATUM;
+    static const std::string CALENDAR; // WKT2-2018
+    static const std::string TIMEORIGIN;
+    static const std::string TIMECRS;
+    static const std::string VERTICALEXTENT;
+    static const std::string TIMEEXTENT;
+    static const std::string USAGE;            // WKT2-2018
+    static const std::string DYNAMIC;          // WKT2-2018
+    static const std::string FRAMEEPOCH;       // WKT2-2018
+    static const std::string MODEL;            // WKT2-2018
+    static const std::string VELOCITYGRID;     // WKT2-2018
+    static const std::string ENSEMBLE;         // WKT2-2018
+    static const std::string MEMBER;           // WKT2-2018
+    static const std::string ENSEMBLEACCURACY; // WKT2-2018
+    static const std::string DERIVEDPROJCRS;   // WKT2-2018
+    static const std::string BASEPROJCRS;      // WKT2-2018
+    static const std::string EDATUM;
+    static const std::string ENGCRS;
+    static const std::string PDATUM;
+    static const std::string PARAMETRICCRS;
+    static const std::string PARAMETRICUNIT;
+    static const std::string BASEVERTCRS;
+    static const std::string BASEENGCRS;
+    static const std::string BASEPARAMCRS;
+    static const std::string BASETIMECRS;
+
+    // WKT2 alternate (longer or shorter)
+    static const std::string GEODETICCRS;
+    static const std::string GEODETICDATUM;
+    static const std::string PROJECTEDCRS;
+    static const std::string PRIMEMERIDIAN;
+    static const std::string GEOGRAPHICCRS; // WKT2-2018
+    static const std::string TRF;           // WKT2-2018
+    static const std::string VERTICALCRS;
+    static const std::string VERTICALDATUM;
+    static const std::string VRF; // WKT2-2018
+    static const std::string TIMEDATUM;
+    static const std::string ENGINEERINGDATUM;
+    static const std::string ENGINEERINGCRS;
+    static const std::string PARAMETRICDATUM;
+
+    static const std::vector<std::string> &constants() { return constants_; }
+
+  private:
+    static std::vector<std::string> constants_;
+    static const char *createAndAddToConstantList(const char *text);
+};
+
+} // namespace io
+
+NS_PROJ_END
+
+//! @endcond
+
+#endif // IO_INTERNAL_HH_INCLUDED