From 8ffd7b73ecbb2d5f7952d1a84c6d5c023d19968c Mon Sep 17 00:00:00 2001 From: Mamoru TASAKA Date: Tue, 21 Dec 2021 20:07:43 +0900 Subject: [PATCH] g1second_order_general_extended_packing: preserve significant bits for signedness on 32bit In g1second_order_general_extended_packing, firstOrderValues or so are restored with grib_get_long_array(), and the restored values are stored in "long" type array. So on 32 bit system, when "bits_per_value" is set to 32 and 32 bit unsigned values are saved with grib_set_long_array(), restored values by grib_get_long_array() are recognized as negative value, which results in wrong result (in grib_second_order.sh). For now, on linux 32 bit system, save 1 significant bit for signedness and restrict bits_per_value to 31, and relax allowed error due to this change. --- ...lass_data_g1second_order_general_extended_packing.c | 10 +++++++++- tests/grib_second_order.sh | 7 ++++++- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/src/grib_accessor_class_data_g1second_order_general_extended_packing.c b/src/grib_accessor_class_data_g1second_order_general_extended_packing.c index 7293d26b..986b1528 100644 --- a/src/grib_accessor_class_data_g1second_order_general_extended_packing.c +++ b/src/grib_accessor_class_data_g1second_order_general_extended_packing.c @@ -1248,7 +1248,15 @@ static int get_bits_per_value(grib_handle* h, const char* bits_per_value_str, lo * because it has already been changed to second order! * We have to take precision=1 for IEEE which is 32bits */ - *bits_per_value = 32; + /* But on 32bit, the most significant bit is for signnedness, so we have to drop one bit + * because it has already been changed to second order! + * We have to take precision=1 for IEEE which is 32bits + */ + if (sizeof(long) == 4) { + *bits_per_value = 31; + } else { + *bits_per_value = 32; + } } return err; } diff --git a/tests/grib_second_order.sh b/tests/grib_second_order.sh index be2e2184..ae01c20a 100755 --- a/tests/grib_second_order.sh +++ b/tests/grib_second_order.sh @@ -143,11 +143,16 @@ grib_check_key_equals $temp3 packingType grid_second_order # ECC-1219: packingType conversion from grid_ieee to grid_second_order # --------------------------------------------------------------------- +if [ $ECCODES_ON_LINUX_32BIT -eq 1 ] ; then + ALLOWED_ERROR=7e-06 +else + ALLOWED_ERROR=3e-06 +fi if [ $ECCODES_ON_WINDOWS -eq 0 ]; then infile=grid_ieee.grib ${tools_dir}/grib_set -r -s packingType=grid_second_order $infile $temp1 grib_check_key_equals $temp1 packingType grid_second_order - ${tools_dir}/grib_compare -cdata:n -R all=3e-06 $infile $temp1 + ${tools_dir}/grib_compare -cdata:n -R all=$ALLOWED_ERROR $infile $temp1 fi # Second order doesn't have a proper representation for constant fields -- 2.33.1