Introduce compatibility for cs2cs-style proj-strings into the 4D API.

Parameters such as towgs84, nadgrids and geoidgrids was previously only
handled by pj_transform(). This commit add a compatibility layer in
proj_create() by calling the pj_cs2cs_emulation_setup() function. This
function sets up a handful of predefined transformation objects on the
PJ object that is being created. Each of these transformation objects
are related to the cs2cs-style parameters we are trying to emulate in
the 4D API. That is, if the +towgs84 parameters is used we create
P->helmert with the parameters specified in +towgs84. Similarly for
+axis, +nadgrids and +geoidgrids. When these transformation objects
exists we use them in the prepare and finalize functions in pj_fwd/
pj_inv. If no cs2cs-style parametes are specified we skip those
parts of the prepare and finalizing steps.

Co-authored-by:Thomas Knudsen <thokn@sdfe.dk>
Co-authored-by:Kristian Evers <kristianevers@gmail.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/src/pj_malloc.c b/src/pj_malloc.c
index 63278a56..cfb7f658 100644
--- a/src/pj_malloc.c
+++ b/src/pj_malloc.c
@@ -162,6 +162,32 @@ void *pj_dealloc_params (PJ_CONTEXT *ctx, paralist *start, int errlev) {
 }
 
 
+
+
+/************************************************************************/
+/*                              pj_free()                               */
+/*                                                                      */
+/*      This is the application callable entry point for destroying     */
+/*      a projection definition.  It does work generic to all           */
+/*      projection types, and then calls the projection specific        */
+/*      free function, P->destructor(), to do local work.               */
+/*      In most cases P->destructor()==pj_default_destructor.           */
+/************************************************************************/
+
+void pj_free(PJ *P) {
+    if (0==P)
+        return;
+    /* free projection parameters - all the hard work is done by */
+    /* pj_default_destructor, which is supposed */
+    /* to be called as the last step of the local destructor     */
+    /* pointed to by P->destructor. In most cases,               */
+    /* pj_default_destructor actually *is* what is pointed to    */
+    P->destructor (P, 0);
+}
+
+
+
+
 /*****************************************************************************/
 void *pj_default_destructor (PJ *P, int errlev) {   /* Destructor */
 /*****************************************************************************
@@ -196,6 +222,14 @@ void *pj_default_destructor (PJ *P, int errlev) {   /* Destructor */
     /* free parameter list elements */
     pj_dealloc_params (pj_get_ctx(P), P->params, errlev);
 
+    /* free the cs2cs emulation elements */
+    pj_free (P->axisswap);
+    pj_free (P->helmert);
+    pj_free (P->cart);
+    pj_free (P->cart_wgs84);
+    pj_free (P->hgridshift);
+    pj_free (P->vgridshift);
+
     pj_dealloc (P->opaque);
     return pj_dealloc(P);
 }