cpp conversion: remove useless pj_, PJ_ and proj_ filename prefixes

1 files changed, 74 insertions, 0 deletions

diff --git a/src/projections/gstmerc.cpp b/src/projections/gstmerc.cpp
new file mode 100644
index 00000000..9b819bac
--- /dev/null
+++ b/src/projections/gstmerc.cpp
@@ -0,0 +1,74 @@
+#define PJ_LIB__
+
+#include <errno.h>
+#include <math.h>
+
+#include "projects.h"
+
+PROJ_HEAD(gstmerc, "Gauss-Schreiber Transverse Mercator (aka Gauss-Laborde Reunion)")
+    "\n\tCyl, Sph&Ell\n\tlat_0= lon_0= k_0=";
+
+namespace { // anonymous namespace
+struct pj_opaque {
+    double lamc;
+    double phic;
+    double c;
+    double n1;
+    double n2;
+    double XS;
+    double YS;
+};
+} // anonymous namespace
+
+
+static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
+    XY xy = {0.0,0.0};
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
+    double L, Ls, sinLs1, Ls1;
+
+    L = Q->n1*lp.lam;
+    Ls = Q->c + Q->n1 * log(pj_tsfn(-1.0 * lp.phi, -1.0 * sin(lp.phi), P->e));
+    sinLs1 = sin(L) / cosh(Ls);
+    Ls1 = log(pj_tsfn(-1.0 * asin(sinLs1), 0.0, 0.0));
+    xy.x = (Q->XS + Q->n2*Ls1) * P->ra;
+    xy.y = (Q->YS + Q->n2*atan(sinh(Ls) / cos(L))) * P->ra;
+
+    return xy;
+}
+
+
+static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
+    LP lp = {0.0,0.0};
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
+    double L, LC, sinC;
+
+    L = atan(sinh((xy.x * P->a - Q->XS) / Q->n2) / cos((xy.y * P->a - Q->YS) / Q->n2));
+    sinC = sin((xy.y * P->a - Q->YS) / Q->n2) / cosh((xy.x * P->a - Q->XS) / Q->n2);
+    LC = log(pj_tsfn(-1.0 * asin(sinC), 0.0, 0.0));
+    lp.lam = L / Q->n1;
+    lp.phi = -1.0 * pj_phi2(P->ctx, exp((LC - Q->c) / Q->n1), P->e);
+
+    return lp;
+}
+
+
+PJ *PROJECTION(gstmerc) {
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
+        return pj_default_destructor (P, ENOMEM);
+    P->opaque = Q;
+
+    Q->lamc = P->lam0;
+    Q->n1 = sqrt(1.0 + P->es * pow(cos(P->phi0), 4.0) / (1.0 - P->es));
+    Q->phic = asin(sin(P->phi0) / Q->n1);
+    Q->c = log(pj_tsfn(-1.0 * Q->phic, 0.0, 0.0))
+         - Q->n1 * log(pj_tsfn(-1.0 * P->phi0, -1.0 * sin(P->phi0), P->e));
+    Q->n2 = P->k0 * P->a * sqrt(1.0 - P->es) / (1.0 - P->es * sin(P->phi0) * sin(P->phi0));
+    Q->XS = 0;
+    Q->YS = -1.0 * Q->n2 * Q->phic;
+
+    P->inv = s_inverse;
+    P->fwd = s_forward;
+
+    return P;
+}