Merge RFC4 (#1865)

This commit is the result of the squashing of rfc4_dev branch in a single
commit. It implements mostly RFC 4 related work.

* Grid handling:
  - remove obsolete and presumably unfinished implementation of grid catalog functionality
  - all grid functionality is in grids.cpp/.hpp
  - vertical and horizontal grid shift: rework to no longer load whole grid into memory
  - remove hgrids and vgrids member from PJ structure, and store them in hgridshift/vgridshift/deformation structures
  - build systems: add optional libtiff dependency. Must be explicitly disabled if not desired
  - add support for horizontal and vertical grids in GeoTIFF, if libtiff is available
  - add GenericShiftGridSet and GenericShiftGrid classes, relying on TIFF grids, that can be used for generic purpose grid-based adjustment
  - add a +proj=xyzgridshift method to perform geocentric translation by grid. Used for French NTF to RGF93 transformation using gr3df97a.tif grid
  - deformation: add support for +grids= for GeoTIFF grids
  - horizontal grid shift: fix failures on points slightly outside a subgrid (fixes #209)

* File management:
  - add a filemanager.cpp/.hpp to deal with file related work
  - test for legacy proj_api.h fileapi
  - proj.h: add proj_context_set_fileapi() and proj_context_set_sqlite3_vfs_name() (fixes #866)
  - add capability to read resource files from the user writable directory

* Network access:
  - build systems: add optional curl dependency
  - add a curl-based default implementation for network related functionality
  - proj.h: add C API to control network functionality, and optionaly provide network callbacks
  - add data/proj.ini with default settings
  - add a SQLite3 local cache of downloaded chunks
  - add proj_is_download_needed() and proj_download_file()

* Use Win32 Unicode APIs and expect all strings to be UTF-8 (fixes #1765)
  For backward compatibility, if PROJ_LIB content is found to be not UTF-8 or
  pointing to a non existing directory, then an attempt at interpretating it
  in the ANSI page encoding is done.
  proj_context_set_search_paths() now assumes strings to be in UTF-8, and
  functions returning paths will also return values in UTF-8.

1 files changed, 0 insertions, 98 deletions

diff --git a/src/nad_cvt.cpp b/src/nad_cvt.cpp
deleted file mode 100644
index e8b8e9b7..00000000
--- a/src/nad_cvt.cpp
+++ /dev/null
@@ -1,98 +0,0 @@
-#define PJ_LIB__
-
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "proj.h"
-#include "proj_internal.h"
-#include <math.h>
-
-#include <limits>
-
-#define MAX_ITERATIONS 10
-#define TOL 1e-12
-
-PJ_LP nad_cvt(projCtx ctx, PJ_LP in, int inverse, struct CTABLE *ct, int grid_count, PJ_GRIDINFO **tables) {
-    PJ_LP t, tb,del, dif;
-    int i = MAX_ITERATIONS;
-    const double toltol = TOL*TOL;
-
-    if (in.lam == HUGE_VAL)
-        return in;
-
-    /* normalize input to ll origin */
-    tb = in;
-    tb.lam -= ct->ll.lam;
-    tb.phi -= ct->ll.phi;
-    tb.lam = adjlon (tb.lam - M_PI) + M_PI;
-
-    t = nad_intr (tb, ct);
-    if (t.lam == HUGE_VAL)
-        return t;
-
-    if (!inverse) {
-        in.lam -= t.lam;
-        in.phi += t.phi;
-        return in;
-    }
-
-    t.lam = tb.lam + t.lam;
-    t.phi = tb.phi - t.phi;
-
-    do {
-        del = nad_intr(t, ct);
-
-        /* In case we are (or have switched) on the null grid, exit now */
-        if( del.lam == 0 && del.phi == 0 )
-            break;
-
-        /* We can possibly go outside of the initial guessed grid, so try */
-        /* to fetch a new grid into which iterate... */
-        if (del.lam == HUGE_VAL)
-        {
-            if( grid_count == 0 )
-                break;
-            PJ_LP lp;
-            lp.lam = t.lam + ct->ll.lam;
-            lp.phi = t.phi + ct->ll.phi;
-            auto newCt = find_ctable(ctx, lp, grid_count, tables);
-            if( newCt == nullptr || newCt == ct )
-                break;
-            pj_log(ctx, PJ_LOG_DEBUG_MINOR, "Switching from grid %s to grid %s",
-                   ct->id,
-                   newCt->id);
-            ct = newCt;
-            t.lam = lp.lam - ct->ll.lam;
-            t.phi = lp.phi - ct->ll.phi;
-            tb = in;
-            tb.lam -= ct->ll.lam;
-            tb.phi -= ct->ll.phi;
-            tb.lam = adjlon (tb.lam - M_PI) + M_PI;
-            dif.lam = std::numeric_limits<double>::max();
-            dif.phi = std::numeric_limits<double>::max();
-            continue;
-        }
-
-        dif.lam = t.lam - del.lam - tb.lam;
-           dif.phi = t.phi + del.phi - tb.phi;
-        t.lam -= dif.lam;
-        t.phi -= dif.phi;
-
-    } while (--i && (dif.lam*dif.lam + dif.phi*dif.phi > toltol)); /* prob. slightly faster than hypot() */
-
-    if (i==0) {
-        /* If we had access to a context, this should go through pj_log, and we should set ctx->errno */
-        if (getenv ("PROJ_DEBUG"))
-            fprintf( stderr, "Inverse grid shift iterator failed to converge.\n" );
-        t.lam = t.phi = HUGE_VAL;
-        return t;
-    }
-
-    /* and again: pj_log and ctx->errno */
-    if (del.lam==HUGE_VAL && getenv ("PROJ_DEBUG"))
-        fprintf (stderr, "Inverse grid shift iteration failed, presumably at grid edge.\nUsing first approximation.\n");
-
-    in.lam = adjlon (t.lam + ct->ll.lam);
-    in.phi = t.phi + ct->ll.phi;
-    return in;
-}