Add proj_list_* functions that exposes various internal lists (#579)

Fixes #173, #187 and #220

src/PJ_cart.c

@@ -240,6 +240,11 @@ int pj_cart_selftest (void) {
     PJ_DERIVS derivs;
     PJ_FACTORS factors;
 
+    const PJ_OPERATIONS *oper_list;
+    const PJ_ELLPS *ellps_list;
+    const PJ_UNITS *unit_list;
+    const PJ_PRIME_MERIDIANS *pm_list;
+
     int err;
     size_t n, sz;
     double dist, h, t;
@@ -562,6 +567,22 @@ int pj_cart_selftest (void) {
 
     proj_destroy(P);
 
+    /* Check that proj_list_* functions work by looping through them */
+    n = 0;
+    for (oper_list = proj_list_operations(); oper_list->id; ++oper_list) n++;
+    if (n == 0) return 90;
+
+    n = 0;
+    for (ellps_list = proj_list_ellps(); ellps_list->id; ++ellps_list) n++;
+    if (n == 0) return 91;
+
+    n = 0;
+    for (unit_list = proj_list_units(); unit_list->id; ++unit_list) n++;
+    if (n == 0) return 92;
+
+    n = 0;
+    for (pm_list = proj_list_prime_meridians(); pm_list->id; ++pm_list) n++;
+    if (n == 0) return 93;
 
     return 0;
 }

src/pj_obs_api.c

@@ -780,6 +780,22 @@ PJ_FACTORS proj_factors(PJ *P, const LP lp) {
 }
 
 
+const PJ_ELLPS *proj_list_ellps(void) {
+    return pj_get_ellps_ref();
+}
+
+const PJ_UNITS *proj_list_units(void) {
+    return pj_get_units_ref();
+}
+
+const PJ_OPERATIONS *proj_list_operations(void) {
+    return pj_get_list_ref();
+}
+
+const PJ_PRIME_MERIDIANS *proj_list_prime_meridians(void) {
+    return pj_get_prime_meridians_ref();
+}
+
 double proj_torad (double angle_in_degrees) { return PJ_TORAD (angle_in_degrees);}
 double proj_todeg (double angle_in_radians) { return PJ_TODEG (angle_in_radians);}
 

src/proj.def

@@ -143,3 +143,7 @@ EXPORTS
     proj_derivatives               @130
     proj_factors                   @131
 
+    proj_list_operations           @132
+    proj_list_ellps                @133
+    proj_list_units                @134
+    proj_list_prime_meridians      @135

src/proj.h

@@ -205,6 +205,23 @@ typedef struct PJ_GRID_INFO PJ_GRID_INFO;
 struct PJ_INIT_INFO;
 typedef struct PJ_INIT_INFO PJ_INIT_INFO;
 
+/* Data types for list of operations, ellipsoids, datums and units used in PROJ.4 */
+struct PJ_LIST;
+typedef struct PJ_LIST PJ_OPERATIONS;
+
+struct PJ_ELLPS;
+typedef struct PJ_ELLPS PJ_ELLPS;
+
+struct PJ_DATUMS;
+typedef struct PJ_DATUMS PJ_DATUMS;
+
+struct PJ_UNITS;
+typedef struct PJ_UNITS PJ_UNITS;
+
+struct PJ_PRIME_MERIDIANS;
+typedef struct PJ_PRIME_MERIDIANS PJ_PRIME_MERIDIANS;
+
+
 /* Omega, Phi, Kappa: Rotations */
 typedef struct {double o, p, k;}  PJ_OPK;
 
@@ -410,6 +427,12 @@ PJ_PROJ_INFO proj_pj_info(PJ *P);
 PJ_GRID_INFO proj_grid_info(const char *gridname);
 PJ_INIT_INFO proj_init_info(const char *initname);
 
+/* List functions: */
+/* Get lists of operations, ellipsoids, units and prime meridians. */
+const PJ_OPERATIONS       *proj_list_operations(void);
+const PJ_ELLPS            *proj_list_ellps(void);
+const PJ_UNITS            *proj_list_units(void);
+const PJ_PRIME_MERIDIANS  *proj_list_prime_meridians(void);
 
 /* These are trivial, and while occasionaly useful in real code, primarily here to       */
 /* simplify demo code, and in acknowledgement of the proj-internal discrepancy between   */