read_sd.c

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#include <string.h>
#include "l1io.h"
#include <mfhdf.h>
 
int32 read_sd(l1info_struct l1info, char *arr_name, float *array)
/*******************************************************************
 
   read_sd
 
   purpose: read a full science dataset to a float array
 
   Returns type: int32 - return status: 0 is good
 
   Parameters: (in calling order)
      Type              Name            I/O     Description
      ----              ----            ---     -----------
      struct l1info_struct   l1info      I      information  struct
                                                about the opened file
      char *            arr_name         I      name of science dataset 
                                                to read
      float *           array            O      array of data from the sds
                                                already allocated outside
 
   Modification history:
      Programmer        Date            Description of change
      ----------        ----            ---------------------
      W. Robinson       9-Feb-1995      Original development
 
 *******************************************************************/
 {
    int j;
    int32 index, rank, sdid, numbertype, nattrs, data_dims[5];
    int32 start[5], edge[5];
    char name[H4_MAX_NC_NAME]; /*  MAX_NC_NAME is max # chars for this */
 
    /*
     *  SDnametoindex is used to zero in on the data we want,
     *  ie. get the index of the data
     */
    if ((index = SDnametoindex(l1info.sdfid, arr_name)) < 0) {
        printf("read_sd: couldn't find %s in the dataset\n",
                arr_name);
        return -1;
    }
 
    /*
     *  next, get the SD ID for the data
     */
    if ((sdid = SDselect(l1info.sdfid, index)) < 0) {
        printf("read_sd: Failed in SDselect for item %s\n",
                arr_name);
        return -1;
    }
 
    /*
     *  now, get the size information of the data item
     */
    if (SDgetinfo(sdid, name, &rank, data_dims, &numbertype,
            &nattrs) < 0) {
        printf("read_sd: Failed in SDgetinfo for item %s\n",
                arr_name);
        return -1;
    }
 
    if (numbertype != DFNT_FLOAT32) {
        printf(
                "read_sd: Type of data to be read is not float32 for item %s\n",
                arr_name);
        return -1;
    }
 
    /*
     *  compute the read controls for whole array
     */
 
    for (j = 0; j < rank; j++) {
        start[j] = 0;
        edge[j] = data_dims[j];
    }
 
    /*
     *  read the data
     */
    if (SDreaddata(sdid, start, NULL, edge, array) < 0) {
        printf("read_sd: failure to read data for item %s\n", arr_name);
        return -1;
    }
    return 0;
}