adds support for CDO-generated weight files to weights2vtk

tools/weights2vtk.c

@@ -13,11 +13,18 @@
 #include "yac_utils.h"
 
 #define YAC_WEIGHT_FILE_VERSION_1_0_STRING "yac weight file 1.0"
+#define CDO_WEIGHT_FILE_TITLE "CDO remapping"
 
 // redefine YAC assert macros
 #undef YAC_ASSERT
 #undef YAC_ASSERT_F
 
+enum weight_file_type {
+  WGT_YAC_1_0,
+  WGT_CDO,
+  WGT_UNKNOWN,
+};
+
 static char const * cmd;
 #define STR_USAGE \
   "Usage: %s -S src_grid_type -T tgt_grid_type " \
@@ -198,6 +205,49 @@ int main(int argc, char ** argv) {
   return EXIT_SUCCESS;
 }
 
+static int check_global_attribute(
+  int ncid, char const * att_name, char const * ref_att_text) {
+
+  int att_matches = 0;
+
+  // global attributes
+  size_t att_len;
+  int status = nc_inq_attlen(ncid, NC_GLOBAL, att_name, &att_len);
+  if (status == NC_NOERR) {
+    char * att_text;
+    att_text = malloc(att_len + 1);
+    att_text[att_len] = '\0';
+    YAC_HANDLE_ERROR(nc_get_att_text(ncid, NC_GLOBAL, att_name, att_text));
+    YAC_ASSERT_F(
+      (strlen(ref_att_text) == att_len) &&
+      !strncmp(att_text, ref_att_text, att_len),
+      "NetCDF file contains attribute string \"%s\", "
+      "but its text does not match (\"%s\" != \"%s\")",
+      att_name, att_text, ref_att_text);
+    free(att_text);
+    att_matches = 1;
+  } else if (status == NC_ENOTATT) {
+    status = NC_NOERR;
+  }
+  YAC_HANDLE_ERROR(status);
+  return att_matches;
+}
+
+static enum weight_file_type determine_weight_file_type(int ncid) {
+
+  // check for YAC weight file
+  if (check_global_attribute(
+        ncid, "version", YAC_WEIGHT_FILE_VERSION_1_0_STRING))
+    return WGT_YAC_1_0;
+
+  // check for CDO weight file
+  if (check_global_attribute(
+        ncid, "title", CDO_WEIGHT_FILE_TITLE))
+    return WGT_CDO;
+
+  return WGT_UNKNOWN;
+}
+
 static void read_link_data(
   char const * weight_filename, int src_address_offset,
   int tgt_address_offset, struct link_data ** links,
@@ -208,51 +258,50 @@ static void read_link_data(
   int ncid, dimid, var_id;
   yac_nc_open(weight_filename, NC_NOWRITE, &ncid);
 
-  // global attributes
-  size_t version_len;
-  char * version;
-  YAC_HANDLE_ERROR(nc_inq_attlen(ncid, NC_GLOBAL, "version", &version_len));
-  version = malloc(version_len + 1);
-  version[version_len] = '\0';
-  YAC_HANDLE_ERROR(nc_get_att_text(ncid, NC_GLOBAL, "version", version));
-  YAC_ASSERT(
-    (strlen(YAC_WEIGHT_FILE_VERSION_1_0_STRING) == version_len) &&
-    !strncmp(version, YAC_WEIGHT_FILE_VERSION_1_0_STRING, version_len),
-    "version string from weight file is not \""
-    YAC_WEIGHT_FILE_VERSION_1_0_STRING "\"");
-  free(version);
-
-  size_t str_link_len;
-  char * str_link;
-  var_id = NC_GLOBAL;
-  YAC_HANDLE_ERROR(nc_inq_attlen(ncid, var_id, "contains_links", &str_link_len));
-  str_link = malloc(str_link_len + 1);
-  str_link[str_link_len] = '\0';
-  YAC_HANDLE_ERROR(nc_get_att_text(ncid, var_id, "contains_links", str_link));
-
-  int contains_links =
-    (strlen("TRUE") == str_link_len) &&
-    !strncmp("TRUE", str_link, str_link_len);
+  enum weight_file_type wgt_type = determine_weight_file_type(ncid);
+
   YAC_ASSERT(
-    contains_links ||
-    ((strlen("FALSE") == str_link_len) &&
-    !strncmp("FALSE", str_link, str_link_len)),
-    "invalid global attribute contains_links")
-
-  if (!contains_links) {
-    *links = NULL;
-    *num_links = 0;
-    *src_locations = NULL;
-    *max_src_idx = 0;
-    *max_tgt_idx = 0;
-    return;
+    (wgt_type == WGT_YAC_1_0) ||
+    (wgt_type == WGT_CDO),
+    "ERROR(read_link_data): unsupported weight file type")
+
+  if (wgt_type == WGT_YAC_1_0) {
+
+    size_t str_link_len;
+    char * str_link;
+    var_id = NC_GLOBAL;
+    YAC_HANDLE_ERROR(nc_inq_attlen(ncid, var_id, "contains_links", &str_link_len));
+    str_link = malloc(str_link_len + 1);
+    str_link[str_link_len] = '\0';
+    YAC_HANDLE_ERROR(nc_get_att_text(ncid, var_id, "contains_links", str_link));
+
+    int contains_links =
+      (strlen("TRUE") == str_link_len) &&
+      !strncmp("TRUE", str_link, str_link_len);
+    YAC_ASSERT(
+      contains_links ||
+      ((strlen("FALSE") == str_link_len) &&
+      !strncmp("FALSE", str_link, str_link_len)),
+      "invalid global attribute contains_links")
+
+    free(str_link);
+
+    if (!contains_links) {
+      *links = NULL;
+      *num_links = 0;
+      *src_locations = NULL;
+      *max_src_idx = 0;
+      *max_tgt_idx = 0;
+      return;
+    }
   }
 
   size_t num_wgts = 0;
   yac_nc_inq_dimid(ncid, "num_wgts", &dimid);
   YAC_HANDLE_ERROR(nc_inq_dimlen(ncid, dimid, &num_wgts));
-  YAC_ASSERT(
-    num_wgts == 1, "YAC only supports num_wgts == 1")
+  YAC_ASSERT_F(
+    num_wgts == 1, "unsupported number of weights per link "
+    "(num_wgts = %zu; has to be 1)", num_wgts)
 
   // get number of links from file
   size_t num_links_in_file = 0;
@@ -262,54 +311,79 @@ static void read_link_data(
   *num_links = num_links_in_file;
   *links = malloc(num_links_in_file * sizeof(**links));
 
-  // get number of pointsets
   size_t num_pointsets = 0;
-  yac_nc_inq_dimid(ncid, "num_src_fields", &dimid);
-  YAC_HANDLE_ERROR(nc_inq_dimlen(ncid, dimid, &num_pointsets));
-  YAC_ASSERT(num_pointsets > 0, "no point sets in file")
-
-  // get max location string length from file
-  size_t max_loc_str_len;
-  yac_nc_inq_dimid(ncid, "max_loc_str_len", &dimid);
-  YAC_HANDLE_ERROR(nc_inq_dimlen(ncid, dimid, &max_loc_str_len));
-  YAC_ASSERT(
-    max_loc_str_len == YAC_MAX_LOC_STR_LEN,
-    "wrong max location string length in weight file")
+  unsigned * num_links_per_pointset;
 
-  // get source locations
-  *src_locations = malloc(num_pointsets * sizeof(**src_locations));
-  yac_nc_inq_varid(ncid, "src_locations", &var_id);
+  // read weight file type specific fields
+  switch (wgt_type) {
+    case (WGT_YAC_1_0): {
 
-  for (unsigned i = 0; i < num_pointsets; ++i) {
+      // get number of pointsets
+      yac_nc_inq_dimid(ncid, "num_src_fields", &dimid);
 
-    char loc_str[YAC_MAX_LOC_STR_LEN];
+      num_pointsets = 0;
+      YAC_HANDLE_ERROR(nc_inq_dimlen(ncid, dimid, &num_pointsets));
+      YAC_ASSERT(num_pointsets > 0, "no point sets in file")
 
-    size_t str_start[2] = {i, 0};
-    size_t str_count[2] = {1, YAC_MAX_LOC_STR_LEN};
+      // get max location string length from file
+      size_t max_loc_str_len;
+      yac_nc_inq_dimid(ncid, "max_loc_str_len", &dimid);
+      YAC_HANDLE_ERROR(nc_inq_dimlen(ncid, dimid, &max_loc_str_len));
+      YAC_ASSERT(
+        max_loc_str_len == YAC_MAX_LOC_STR_LEN,
+        "wrong max location string length in weight file")
 
-    YAC_HANDLE_ERROR(nc_get_vara_text(ncid, var_id, str_start, str_count, loc_str));
+      // get source locations
+      *src_locations = malloc(num_pointsets * sizeof(**src_locations));
+      yac_nc_inq_varid(ncid, "src_locations", &var_id);
 
-    (*src_locations)[i] = yac_str2loc(loc_str);
-  }
+      for (unsigned i = 0; i < num_pointsets; ++i) {
 
-  // get target location
-  yac_nc_inq_varid(ncid, "dst_location", &var_id);
-  {
-    char loc_str[YAC_MAX_LOC_STR_LEN];
-    YAC_HANDLE_ERROR(nc_get_var_text(ncid, var_id, loc_str));
-    *tgt_location = yac_str2loc(loc_str);
-  }
+        char loc_str[YAC_MAX_LOC_STR_LEN];
+
+        size_t str_start[2] = {i, 0};
+        size_t str_count[2] = {1, YAC_MAX_LOC_STR_LEN};
+
+        YAC_HANDLE_ERROR(
+          nc_get_vara_text(ncid, var_id, str_start, str_count, loc_str));
+
+        (*src_locations)[i] = yac_str2loc(loc_str);
+      }
+
+      // get target location
+      yac_nc_inq_varid(ncid, "dst_location", &var_id);
+      {
+        char loc_str[YAC_MAX_LOC_STR_LEN];
+        YAC_HANDLE_ERROR(nc_get_var_text(ncid, var_id, loc_str));
+        *tgt_location = yac_str2loc(loc_str);
+      }
+
+      // get number of links per pointset
+      num_links_per_pointset =
+        malloc(num_pointsets * sizeof(*num_links_per_pointset));
+      yac_nc_inq_varid(ncid, "num_links_per_src_field", &var_id);
+      YAC_HANDLE_ERROR(nc_get_var_uint(ncid, var_id, num_links_per_pointset));
 
-  // get number of links per pointset
-  unsigned * num_links_per_pointset =
-    malloc(num_pointsets * sizeof(*num_links_per_pointset));
-  yac_nc_inq_varid(ncid, "num_links_per_src_field", &var_id);
-  YAC_HANDLE_ERROR(nc_get_var_uint(ncid, var_id, num_links_per_pointset));
+      break;
+    }
+    default:
+    case (WGT_CDO): {
+
+      num_pointsets = 1;
+      *src_locations = malloc(num_pointsets * sizeof(**src_locations));
+      (*src_locations)[0] = YAC_LOC_CELL;
+      *tgt_location = YAC_LOC_CELL;
+      num_links_per_pointset =
+        malloc(num_pointsets * sizeof(*num_links_per_pointset));
+      num_links_per_pointset[0] = num_links_in_file;
+      break;
+    }
+  };
 
   for (unsigned points_idx = 0, link_idx = 0; points_idx < num_pointsets;
-       ++points_idx)
+      ++points_idx)
     for (unsigned i = 0; i < num_links_per_pointset[points_idx];
-         ++i, ++link_idx)
+        ++i, ++link_idx)
       (*links)[link_idx].points_idx = points_idx;
   free(num_links_per_pointset);