Expose pj_factors and pj_deriv in public API. (#546)

Expose pj_factors and pj_deriv in public API.

proj_derivatives() and proj_factors() has been
introduced to the public proj.h API. The new functions are simply
wrappers for the original functions. The h argument of the two functions
has been omitted in the new wrappers as it does not seem to be used very
much (if at all?).

1 files changed, 52 insertions, 2 deletions

diff --git a/src/pj_obs_api.c b/src/pj_obs_api.c
index 05fe58f0..b06f0823 100644
--- a/src/pj_obs_api.c
+++ b/src/pj_obs_api.c
@@ -37,7 +37,6 @@
 #include "proj_internal.h"
 #include "projects.h"
 #include <geodesic.h>
-
 #include <stddef.h>
 #include <errno.h>
 
@@ -517,7 +516,56 @@ char *proj_definition_retrieve (PJ *P) {
     return pj_get_def(P, 0);
 }
 
-/* ...and get rid of it safely */
+
+/*****************************************************************************/
+PJ_DERIVS proj_derivatives(const PJ *P, const LP lp) {
+/******************************************************************************
+    Derivatives of coordinates.
+
+    returns PJ_DERIVS. If unsuccessfull error number is set and the returned
+    struct contains NULL data.
+
+******************************************************************************/
+    PJ_DERIVS derivs;
+
+    /* casting to struct DERIVS for compatibility reasons */
+    if (pj_deriv(lp, 1e-5, (PJ *)P, (struct DERIVS *)&derivs)) {
+        /* errno set in pj_derivs */
+        memset(&derivs, 0, sizeof(PJ_DERIVS));
+    }
+
+    return derivs;
+}
+
+
+/*****************************************************************************/
+PJ_FACTORS proj_factors(const PJ *P, const LP lp) {
+/******************************************************************************
+    Cartographic characteristics at point lp.
+
+    Characteristics include meridian, parallel and areal scales, angular
+    distortion, meridian/parallel, meridian convergence and scale error.
+
+    returns PJ_FACTORS. If unsuccessfull error number is set and the returned
+    struct contains NULL data.
+
+******************************************************************************/
+    PJ_FACTORS factors;
+
+    /* pj_factors rely code being zero */
+    factors.code = 0;
+
+    /* casting to struct FACTORS for compatibility reasons */
+    if (pj_factors(lp, (PJ *)P, 0.0, (struct FACTORS *)&factors)) {
+        /* errno set in pj_factors */
+        memset(&factors, 0, sizeof(PJ_FACTORS));
+    }
+
+    return factors;
+}
+
+
+/* Release, or free, memory that was retrieved by the above functions */
 void *proj_release (void *buffer) {
     return pj_dealloc (buffer);
 }
@@ -537,3 +585,5 @@ double proj_dmstor(const char *is, char **rs) {
 char*  proj_rtodms(char *s, double r, int pos, int neg) {
     return rtodms(s, r, pos, neg);
 }
+
+