readexample.c

/*************************************************************************\
* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
* National Laboratory.
* Copyright (c) 2002 The Regents of the University of California, as
* Operator of Los Alamos National Laboratory.
* This file is distributed subject to a Software License Agreement found
* in the file LICENSE that is included with this distribution. 
\*************************************************************************/
 
/* program: readexample.c
 * purpose: simple example of reading an SDDS file
 *
 * Michael Borland, 1994
 $Log: not supported by cvs2svn $
 Revision 1.3  1995/09/06 14:55:58  saunders
 First test release of SDDS1.5
 
 */
#include "SDDS.h"
 
char *USAGE = "readexample <SDDSinput>\n\
This program is a simple example that illustrates the use of\n\
SDDS input routines.\n\
Program by Michael Borland. ("__DATE__
              " "__TIME__
              ", SVN revision: " SVN_VERSION ")\n";
 
#define COLUMNS 2
 
main(int argc, char **argv) {
  SDDS_DATASET SDDS_dataset;
  char *input;
  char *column_name[COLUMNS] = {"f", "FFT"};
  char *column_units[COLUMNS] = {"MHz", ""};
  double *f;
  float *FFT;
  long i, rows, *fl;
 
  if (argc != 2) {
    fprintf(stderr, "error: no input file given\nusage: %s\n", USAGE);
    exit(1);
  }
 
  input = argv[1];
 
  if (!SDDS_InitializeInput(&SDDS_dataset, input)) {
    SDDS_PrintErrors(stderr, SDDS_VERBOSE_PrintErrors);
    exit(1);
  }
 
  for (i = 0; i < COLUMNS; i++) {
    long code;
    if ((code = SDDS_CheckColumn(&SDDS_dataset, column_name[i], column_units[i], 0, NULL)) == SDDS_CHECK_NONEXISTENT) {
      fprintf(stderr, "column %s not in file\n", column_name[i]);
      exit(1);
    }
    if (code == SDDS_CHECK_WRONGUNITS) {
      fprintf(stderr, "column %s doesn't have expected units (%s)\n", column_name[i], column_units[i]);
      exit(1);
    }
  }
 
  if (SDDS_ReadPage(&SDDS_dataset) != 1 || (rows = SDDS_CountRowsOfInterest(&SDDS_dataset)) < 0) {
    fprintf(stderr, "first page of data set is unreadable or empty\n");
    SDDS_PrintErrors(stderr, SDDS_VERBOSE_PrintErrors);
    exit(1);
  }
 
  if (!(f = SDDS_GetColumnInDoubles(&SDDS_dataset, column_name[0]))) {
    fprintf(stderr, "unable to read column %s\n", column_name[0]);
    SDDS_PrintErrors(stderr, SDDS_VERBOSE_PrintErrors);
    exit(1);
  }
 
  if (!(fl = SDDS_GetNumericColumn(&SDDS_dataset, column_name[0], SDDS_LONG))) {
    fprintf(stderr, "unable to read column %s\n", column_name[0]);
    SDDS_PrintErrors(stderr, SDDS_VERBOSE_PrintErrors);
    exit(1);
  }
 
  if (!(FFT = SDDS_GetNumericColumn(&SDDS_dataset, column_name[1], SDDS_FLOAT))) {
    fprintf(stderr, "unable to read column %s\n", column_name[1]);
    SDDS_PrintErrors(stderr, SDDS_VERBOSE_PrintErrors);
    exit(1);
  }
 
  for (i = 0; i < rows; i++)
    fprintf(stderr, "row %ld:  %ld, %e, %e\n", i, fl[i], f[i], FFT[i]);
 
  SDDS_Terminate(&SDDS_dataset);
}