NASA Ocean Color

ocssw V2022

 #include <netcdf.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <math.h>
 #include <stdio.h>
 #include <nc4utils.h>
  
 #define DEFAULT_CHUNK_SIZE 1000
  
 #define NEW_CACHE_SIZE 16000000
 #define NEW_CACHE_NELEMS 2003
 #define NEW_CACHE_PREEMPTION .75 
  
 void nc_init_chunk_cache() {
     /* Change chunk cache. */
     int status = nc_set_chunk_cache(NEW_CACHE_SIZE, NEW_CACHE_NELEMS, NEW_CACHE_PREEMPTION);
     if (status != NC_NOERR) {
         fprintf(stderr, "-E- %s line %d: Could not set NetCDF4 cache size.\n", __FILE__, __LINE__);
         exit(EXIT_FAILURE);
     }
 }
  
 void nc_init_compress(int32_t nc_id, int32_t var_id, int32_t *dimids, int32_t rank,
         size_t *chunksize, int deflate_level) {
     int i, status;
  
     // if deflate level below 0 then don't deflate
     if (deflate_level < 1)
         return;
  
     size_t dimlength;
     if (rank > 3) {
         printf("Whoops!  Refusing to chunk/compress more than 3 dimensions");
         exit(EXIT_FAILURE);
     }
     size_t suggested_size[3] = {32,256,40};
     if (rank == 2) {
         suggested_size[0] = 256;
         suggested_size[1] = 2048;
     }
     // Set  chunksize for each dimension, if one has not been provided
     for (i = 0; i < rank; i++) {
         if (chunksize==NULL || chunksize[i]==0) {
             chunksize[i] = suggested_size[i];
         }
         status = nc_inq_dimlen(nc_id, dimids[i], &dimlength);
         if (status != NC_NOERR) {
             fprintf(stderr, "-E- %s line %d: Could not read size of dimension.\n", __FILE__, __LINE__);
             exit(EXIT_FAILURE);
         }
         if(chunksize[i] > dimlength)
             chunksize[i] = dimlength;
     }
  
     /* Set compression */
     /* First set chunking */
     status = nc_def_var_chunking(nc_id, var_id, NC_CHUNKED, chunksize);
     if (status != NC_NOERR) {
         printf("-E- %s %d: %s \n", __FILE__, __LINE__,
                 nc_strerror(status));
         exit(EXIT_FAILURE);
     }
     /* Now we can set compression */
     status = nc_def_var_deflate(nc_id, var_id, NC_SHUFFLE, 9,
             deflate_level);
     if (status != NC_NOERR) {
         printf("-E- %s %d: %s \n", __FILE__, __LINE__,
                 nc_strerror(status));
         exit(EXIT_FAILURE);
     }
 }
  
 /* Check a set of chunksizes to see if they specify a chunk that is too big. */
 int check_chunksizes(size_t type_len, int32_t ndims, const size_t *chunksizes) {
     double dprod;
     int d;
  
     dprod = (double) type_len;
     for (d = 0; d < ndims; d++) {
         if (chunksizes[d] < 1)
             return NC_EINVAL;
         dprod *= (double) chunksizes[d];
     }
  
     if (dprod > (double) NC_MAX_UINT)
         return NC_EBADCHUNK;
  
     return NC_NOERR;
 }