Function ellps_shape

ThirdParty/libproj/vtklibproj/src/ell_set.cpp:246–353

/

/***************************************************************************************/
static int ellps_shape (PJ *P) {
/***************************************************************************************/
    const char *keys[]  = {"rf", "f", "es", "e", "b"};
    paralist *par = nullptr;
    size_t i, len;

    par = nullptr;
    len = sizeof (keys) / sizeof (char *);

    free(P->def_shape);
    P->def_shape = nullptr;

    /* Check which shape key is specified */
    for (i = 0;  i < len;  i++) {
        par = pj_get_param (P->params, keys[i]);
        if (par)
            break;
    }

    /* Not giving a shape parameter means selecting a sphere, unless shape */
    /* has been selected previously via ellps=xxx */
    if (nullptr==par && P->es != 0)
        return 0;
    if (nullptr==par && P->es==0) {
        P->es = P->f = 0;
        P->b = P->a;
        return 0;
    }

    P->def_shape = pj_strdup(par->param);
    par->used = 1;
    P->es = P->f = P->b = P->e = P->rf = 0;

    switch (i) {

    /* reverse flattening, rf */
    case 0:
         P->rf = pj_atof (pj_param_value (par));
         if (HUGE_VAL==P->rf || P->rf <= 0)
         {
            proj_log_error(P, _("Invalid value for rf. Should be > 0"));
            return proj_errno_set (P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);
         }
         P->f = 1 / P->rf;
         P->es = 2*P->f - P->f*P->f;
         break;

    /* flattening, f */
    case 1:
        P->f = pj_atof (pj_param_value (par));
        if (HUGE_VAL==P->f || P->f < 0)
        {
            proj_log_error(P, _("Invalid value for f. Should be >= 0"));
            return proj_errno_set (P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);
        }

        P->rf = P->f != 0.0 ? 1.0/P->f: HUGE_VAL;
        P->es = 2*P->f - P->f*P->f;