Add work-around for potentially unavailable grib_get_length function.

* It's only in grib_api releases 1.12 and after.

configure

@@ -27312,6 +27312,17 @@ else
   ENABLE_NETCDF_FALSE=
 fi
+for ac_func in grib_get_length
+do :
+  ac_fn_c_check_func "$LINENO" "grib_get_length" "ac_cv_func_grib_get_length"
+if test "x$ac_cv_func_grib_get_length" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_GRIB_GET_LENGTH 1
+_ACEOF
+
+fi
+done
+
 #  ----------------------------------------------------------------------
 # Compile with MPI support
 # Sed expression to map a string onto a valid argument string part.

configure.ac

@@ -129,6 +129,7 @@ AC_CHECK_LIB(m, floor)
 # Add basic configure options
 ACX_OPTIONS
 AM_CONDITIONAL([ENABLE_NETCDF],[test x$ENABLE_NETCDF = xyes])
+AC_CHECK_FUNCS([grib_get_length])
 #  ----------------------------------------------------------------------
 # Compile with MPI support
 AC_ARG_ENABLE([mpi],

src/config.h.in

@@ -46,6 +46,9 @@
 /* Define to 1 if you have the <grib_api.h> header file. */
 #undef HAVE_GRIB_API_H
 
+/* Define to 1 if you have the `grib_get_length' function. */
+#undef HAVE_GRIB_GET_LENGTH
+
 /* Define to 1 if you have the <hdf5.h> header file. */
 #undef HAVE_HDF5_H
 

src/gribapi_utilities.c

@@ -28,11 +28,45 @@
 //A simple wrapper for grib_get_string() that returns a newly allocated string.
 char* gribCopyString(grib_handle* gribHandle, const char* key)
 {
+  char* result = NULL;
   size_t length;
-  if(grib_get_length(gribHandle, key, &length)) return NULL;
-  char* result = xmalloc(length);
-  if(!grib_get_string(gribHandle, key, result, &length)) return result;
+#ifdef HAVE_GRIB_GET_LENGTH
+  if(!grib_get_length(gribHandle, key, &length))
+  {
+    char* result = xmalloc(length);
+    if(!grib_get_string(gribHandle, key, result, &length))
+      result = xrealloc(result, length);
+    else
+    {
+      free(result);
+      result = NULL;
+    }
+  }
+#else
+  length = 1024;         /* there's an implementation limit
+                          * that makes strings longer than
+                          * this unlikely in grib_api versions
+                          * not providing grib_get_length */
+  int rc;
+  result = xmalloc(length);
+  while ((rc = grib_get_string(gribHandle, key, result, &length))
+         == GRIB_BUFFER_TOO_SMALL || rc == GRIB_ARRAY_TOO_SMALL)
+  {
+    if (length <= 1024UL * 1024UL)
+    {
+      length *= 2;
+      result = xrealloc(result, length);
+    }
+    else
+      break;
+  }
+  if (!rc)
+  {
+    result = xrealloc(result, length);
+    return result;
+  }
   free(result);
+#endif
   return NULL;
 }
 
@@ -40,12 +74,29 @@ char* gribCopyString(grib_handle* gribHandle, const char* key)
 //Returns true if the key exists and the value is equal to the given string.
 bool gribCheckString(grib_handle* gribHandle, const char* key, const char* expectedValue)
 {
-  size_t expectedLength = strlen(expectedValue) + 1, length;
+  size_t expectedLength = strlen(expectedValue) + 1;
+#ifdef HAVE_GRIB_GET_LENGTH
+  size_t length;
   if(grib_get_length(gribHandle, key, &length)) return false;
   if(length != expectedLength) return false;
-  char value[length];
+  char *value = xmalloc(length);
   if(grib_get_string(gribHandle, key, value, &length)) return false;
-  return !strcmp(value, expectedValue);
+  int rc = !strcmp(value, expectedValue);
+  free(value);
+#else
+  char *value = gribCopyString(gribHandle, key);
+  int rc;
+  if (value)
+  {
+    rc = strlen(value) + 1 == expectedLength ?
+      !strcmp(value, expectedValue)
+      : false;
+  }
+  else
+    rc = false;
+  free(value);
+#endif
+  return rc;
 }
 
 //A simple wrapper for grib_get_long() for the usecase that the result is only compared to a given constant value.

src/iterator_grib.c

@@ -611,7 +611,12 @@ int cdiGribIterator_getLong(CdiGribIterator* me, const char* key, long* result)
 */
 int cdiGribIterator_getLength(CdiGribIterator* me, const char* key, size_t* result)
 {
+#ifdef HAVE_GRIB_GET_LENGTH
   return grib_get_length(me->gribHandle, key, result);
+#else
+  Error("unimplemented");
+  return -1;
+#endif
 }
 
 /**