GRIB-364: Memory fault when packing GRIB2 files with 'log preprocessing'

src/grib_accessor_class_data_g2simple_packing.c

@@ -216,7 +216,17 @@ static int pack_double(grib_accessor* a, const double* cval, size_t* len)
         for (i = 0; i < n_vals; i++)
             val[i] += units_bias;
 
-    ret = super->pack_double(a, val, len);
+    if (super != grib_accessor_class_data_g2simple_packing) {
+        /* Normal case: parent not same as me! */
+        ret = super->pack_double(a, val, len);
+    }
+    else {
+        /* GRIB-364: simple packing with logarithm pre-processing */
+        grib_accessor_class* super2 = NULL;
+        Assert(super->super);
+        super2 = *(super->super);
+        ret    = super2->pack_double(a, val, len);
+    }
     switch (ret) {
         case GRIB_CONSTANT_FIELD:
             grib_buffer_replace(a, NULL, 0, 1, 1);

src/grib_accessor_class_data_g2simple_packing_with_preprocessing.c

@@ -183,6 +183,7 @@ static int unpack_double(grib_accessor* a, double* val, size_t* len)
 {
     grib_accessor_data_g2simple_packing_with_preprocessing* self = (grib_accessor_data_g2simple_packing_with_preprocessing*)a;
     grib_accessor_class* super                                   = *(a->cclass->super);
+    grib_accessor_class* super2                                  = NULL;
 
     size_t n_vals = 0;
     long nn       = 0;
@@ -213,7 +214,9 @@ static int unpack_double(grib_accessor* a, double* val, size_t* len)
         return err;
     }
 
-    err = super->unpack_double(a, val, &n_vals);
+    Assert(super->super);
+    super2 = *(super->super);
+    err    = super2->unpack_double(a, val, &n_vals); /* GRIB-364 */
     if (err != GRIB_SUCCESS)
         return err;
 
@@ -266,6 +269,7 @@ static int pre_processing_func(double* values, long length, long pre_processing,
     int ret         = 0;
     double min      = values[0];
     double next_min = values[0];
+    Assert(length > 0);
 
     switch (pre_processing) {
         /* NONE */
@@ -286,15 +290,21 @@ static int pre_processing_func(double* values, long length, long pre_processing,
                 }
                 if (min > 0) {
                     *pre_processing_parameter = 0;
-                    for (i = 0; i < length; i++)
+                    for (i = 0; i < length; i++) {
+                        DebugAssert(values[i] > 0);
                         values[i] = log(values[i]);
+                    }
                 }
                 else {
+                    double ppp                = 0;
                     *pre_processing_parameter = next_min - 2 * min;
                     if (next_min == min)
                         return ret;
-                    for (i = 0; i < length; i++)
-                        values[i] = log(values[i] + *pre_processing_parameter);
+                    ppp = *pre_processing_parameter;
+                    for (i = 0; i < length; i++) {
+                        DebugAssert((values[i] + ppp) > 0);
+                        values[i] = log(values[i] + ppp);
+                    }
                 }
             }
             else {

tests/grib_change_packing.sh

@@ -18,8 +18,8 @@ packing1="
 packing2="
     grid_ieee
     grid_simple
-    grid_simple_matrix"
-#TODO: grid_simple_log_preprocessing
+    grid_simple_matrix
+    grid_simple_log_preprocessing"
 
 if [ $HAVE_JPEG -eq 1 ]; then
     packing2="grid_jpeg "$packing2