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/* This is part of the netCDF package.
Copyright 2005 University Corporation for Atmospheric Research/Unidata
See COPYRIGHT file for conditions of use.
*/
/*
* Example illustrates the use of SZIP compression in netCDF5
* Taken from HDF5 example.
*/
#include <config.h>
#include <stdlib.h>
#include <stdio.h>
#include "nc_tests.h"
#include "err_macros.h"
#include "netcdf.h"
#undef PLAIN
#define USECLOSE
/* Szip Constants. */
#define HDF5_FILTER_SZIP 4
#define H5_SZIP_MAX_PIXELS_PER_BLOCK_IN 32
#define H5_SZIP_MAX_PIXELS_PER_BLOCK_OUT 64
/* Option Mask Flags (Refere to HDF5 szip documentation) */
#define H5_SZIP_ALLOW_K13_OPTION_MASK 1 /*Allows k split = 13 compression mode. (Default)*/
#define H5_SZIP_CHIP_OPTION_MASK 2 /*Compresses exactly as in hardware*/
#define H5_SZIP_EC_OPTION_MASK 4 /*Selects entropy coding method. (Default)*/
#define H5_SZIP_NN_OPTION_MASK 32 /*Selects nearest neighbor coding method*/
#define NX 500
#define NY 600
#define CH_NX 100
#define CH_NY 25
static void initialize(void);
static int compare(void);
static float buf[NX][NY];
static float buf_r[NX][NY];
int
main(void)
{
int ncid, varid, dimids[2];
size_t dims[2], chunk_size[2];
unsigned int szip_params[2]; /* [0]=options_mask [1]=pixels_per_block */
int errcnt = 0;
/* Create a new file using read/write access. */
if(nc_create("testszip.nc", NC_CLOBBER|NC_NETCDF4, &ncid)) ERR;
/* Create dims */
dims[0] = NX;
dims[1] = NY;
if(nc_def_dim(ncid, "x", dims[0], &dimids[0])) ERR;
if(nc_def_dim(ncid, "y", dims[1], &dimids[1])) ERR;
/* Create a dimensioned variable */
if(nc_def_var(ncid, "datasetF32", NC_FLOAT, 2, dimids, &varid)) ERR;
/* no fill */
if(nc_def_var_fill(ncid, varid, 1, NULL)) ERR;
/* Define chunking for the variable:
* the raw data is to be partitioned into 100x100 element chunks.
*/
chunk_size[0] = CH_NX;
chunk_size[1] = CH_NY;
if(nc_def_var_chunking(ncid, varid, NC_CHUNKED, chunk_size)) ERR;
#ifndef PLAIN
/*
* Set parameters for SZIP compression; check the description of
* the H5Pset_szip function in the HDF5 Reference Manual for more
* information.
*/
szip_params[0] = H5_SZIP_NN_OPTION_MASK;
szip_params[1] = H5_SZIP_MAX_PIXELS_PER_BLOCK_IN;
{ int stat = nc_def_var_filter(ncid, varid, HDF5_FILTER_SZIP, 2, szip_params);
if(stat) {
fprintf(stderr,"XXX: %d %s\b",stat,nc_strerror(stat));
ERR;
}
}
#endif
if(nc_enddef(ncid)) ERR;
initialize();
/* Write the array to the file */
if(nc_put_var_float(ncid, varid, &buf[0][0])) ERR;
#ifdef USECLOSE
/* Close and re-open the file */
if(nc_close(ncid)) ERR;
if(nc_open("testszip.nc", NC_NETCDF4, &ncid)) ERR;
if(nc_inq_varid(ncid, "datasetF32", &varid)) ERR;
#endif
/*
* Read the array. This is similar to writing data,
* except the data flows in the opposite direction.
* Note: Decompression should be automatic.
*/
memset(buf_r,0,sizeof(buf_r));
if(nc_get_var_float(ncid, varid, &buf_r[0][0])) ERR;
/* Do comparison */
errcnt = compare();
if(nc_close(ncid)) ERR;
if(errcnt) ERR;
SUMMARIZE_ERR;
FINAL_RESULTS;
return (errcnt==0?0:1);
}
static int
compare()
{
int i,j;
int errs = 0;
/* Do comparison */
for (i=0; i < NX; i++) {
for (j=0; j < NY; j++) {
if(buf[i][j] != buf_r[i][j]) {
errs++;
printf("mismatch: [%d][%d]: write = %f read=%f\n",
i,j,buf[i][j],buf_r[i][j]);
}
}
}
return errs;
}
static void
initialize(void)
{
int i, j;
/* Initialize data buffer with some bogus data. */
for(i=0; i < NX; i++) {
for(j=0; j < NY; j++) {
buf[i][j] = (float)(i + j);
}
}
}
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