Features: List of enabled ones

src/codes_util.cc

@@ -405,6 +405,18 @@ int compute_scaled_value_and_scale_factor(
     return err;
 }
 
+static const char* known_features[] = {
+    "AEC",
+    "MEMFS",
+    "JPG",
+    "PNG",
+    "ECCODES_THREADS",
+    "ECCODES_OMP_THREADS",
+    "NETCDF",
+    "FORTRAN",
+    "GEOGRAPHY"
+};
+
 #define NUMBER(x) (sizeof(x) / sizeof(x[0]))
 int codes_is_feature_enabled(const char* feature)
 {
@@ -418,19 +430,9 @@ int codes_is_feature_enabled(const char* feature)
     int fortran_enabled       = 0;
     int geography_enabled     = 0;
 
-    const char* known_features[] = {
-        "AEC",
-        "MEMFS",
-        "JPG",
-        "PNG",
-        "ECCODES_THREADS",
-        "ECCODES_OMP_THREADS",
-        "NETCDF",
-        "FORTRAN",
-        "GEOGRAPHY"
-    };
     int found_feature = 0;
-    for (size_t i = 0; i < NUMBER(known_features); ++i) {
+    const size_t num = NUMBER(known_features);
+    for (size_t i = 0; i < num; ++i) {
         if (STR_EQUAL(feature, known_features[i])) {
             found_feature = 1;
             break;
@@ -439,7 +441,7 @@ int codes_is_feature_enabled(const char* feature)
     if (!found_feature) {
         grib_context* c = grib_context_get_default();
         grib_context_log(c, GRIB_LOG_ERROR, "Unknown feature '%s'. Select one of:", feature);
-        for (size_t i = 0; i < NUMBER(known_features); ++i) {
+        for (size_t i = 0; i < num; ++i) {
             grib_context_log(c, GRIB_LOG_ERROR, "\t%s", known_features[i]);
         }
         return 0;
@@ -456,7 +458,7 @@ int codes_is_feature_enabled(const char* feature)
     jpg_enabled = 1;
     #endif
 #endif
-#if defined(HAVE_LIBPNG)
+#if HAVE_LIBPNG
     png_enabled = 1;
 #endif
 #if defined(HAVE_MEMFS)
@@ -508,3 +510,21 @@ int codes_is_feature_enabled(const char* feature)
 
     return 0;
 }
+
+int codes_enabled_features(char* result, size_t* length)
+{
+    const size_t num = NUMBER(known_features);
+    for (size_t i = 0; i < num; ++i) {
+        if (codes_is_feature_enabled(known_features[i])) {
+            strcat(result, known_features[i]);
+            strcat(result, " ");
+        }
+    }
+
+    const size_t actual_length = strlen(result);
+    if (result[actual_length - 1] == ' ')
+        result[actual_length - 1] = '\0';
+    Assert(*length >= actual_length);
+    *length = actual_length;
+    return GRIB_SUCCESS;
+}

src/eccodes.h

@@ -1402,7 +1402,8 @@ int codes_check_message_footer(const void* bytes, size_t length, ProductKind pro
 
 /* Features enabled */
 int codes_is_feature_enabled(const char* feature);
-
+/* result must be allocated by the caller and its length must be large enough */
+int codes_enabled_features(char* result, size_t* length);
 
 /* --------------------------------------- */
 #define CODES_UTIL_GRID_SPEC_REGULAR_LL                   GRIB_UTIL_GRID_SPEC_REGULAR_LL

src/eccodes_prototypes.h

@@ -858,6 +858,8 @@ bool is_sorted_ascending(double arr[], size_t n);
 bool is_sorted_descending(double arr[], size_t n);
 int compute_scaled_value_and_scale_factor(double input, int64_t scaled_value_max, int64_t scale_factor_max, int64_t* ret_value, int64_t* ret_factor);
 int codes_is_feature_enabled(const char* feature);
+int codes_enabled_features(char* result, size_t* length);
+
 
 /* grib_util.cc */
 grib_handle* grib_util_sections_copy(grib_handle* hfrom, grib_handle* hto, int what, int* err);

tests/unit_tests.cc

@@ -807,6 +807,17 @@ void test_is_feature_enabled()
     Assert( 0 == codes_is_feature_enabled("total rubbish") );
 }
 
+void test_codes_enabled_features()
+{
+    printf("Running %s ...\n", __func__);
+
+    size_t len = 512;
+    char* features = (char*)malloc(len * sizeof(char));
+    int err = codes_enabled_features(features, &len);
+    Assert(!err);
+    printf("\tEnabled features are: '%s'\n", features);
+    free(features);
+}
 
 int main(int argc, char** argv)
 {
@@ -874,6 +885,7 @@ int main(int argc, char** argv)
     test_grib2_select_PDTN();
     test_grib2_choose_PDTN();
     test_is_feature_enabled();
+    test_codes_enabled_features();
 
     return 0;
 }