/*********************************************************

             SUBROUTINE READLEVEL

 READLEVEL READS REAL DATA FROM A STANDARD GRID FILE IN BULK FORM.
 THE STANDARD GRID FILE IS A THREE DIMENSIONAL GRID, I,J,K WITH
 I DENOTING LONGITUDINAL, J DENOTING LATITUDINAL, AND K
 DENOTING DEPTH.  WRITELEVEL CAN TAKE AN ARRAY OF ANY SIZE
 AND WRITE IT TO A FILE SET UP FOR THE SAME GRID SIZE OR
 ANOTHER GRID SIZE.

**********************************************************/

readlevel_(

 int *iadim,            /* STARTING LONGITUDE FOR ARRAY */
 int *jadim,            /* STARTING LATITUDE FOR ARRAY */
 int *k1,               /* FIRST DEPTH FOR ARRAY */
 int *idims,            /* STARTING LONGITUDE GRID */
 int *jdims,            /* STARTING LATITUDE GRID */
 int *idime,            /* ENDING LONGITUDE GRID */
 int *jdime,            /* ENDING LATITUDE GRID */
 int *idim,             /* MAXIMUM LONGITUDE SPACING FOR FILE */
 int *jdim,             /* MAXIMUM LATITUDE SPACING FOR FILE */
 int *iparm,            /* MAXIMUM LONGITUDE SPACING FOR DATA ARRAY */
 int *jparm,            /* MAXIMUM LATITUDE SPACING FOR DATA ARRAY */
 int *ks,               /* STARTING DEPTH LEVEL */
 int *ke,               /* ENDING DEPTH LEVEL */
 int *fn,               /* FILE IDENTIFICATION NUMBER */
 float *temp            /* DATA */

            )

{

/***********************************************************

 LEVELSIZE - SIZE OF ONE GRID LEVEL FOR FILE
 RECORD - POINTER TO CORRECT LEVEL FOR FILE
 LATITUDE - POINTER TO CORRECT LATITUDE COORDINATE FOR FILE
 ARRAYSIZE - SIZE OF ONE ARRAY LEVEL
 ARECORD - POINTER TO CORRECT LEVEL FOR ARRAY
 ALATITUDE - POINTER TO CORRECT LATITUDE COORDINATE FOR ARRAY
 K - CURRENT DEPTH POINT FOR FILE
 J - CURRENT LATITUDE POINT FOR FILE
 I - CURRENT LONGITUDE POINT FOR FILE
 KA - CURRENT DEPTH POINT FOR ARRAY
 JA - CURRENT LATITUDE POINT FOR ARRAY
 IA - CURRENT LONGITUDE POINT FOR ARRAY

*************************************************************/

 int levelsize, record, latitude, ll, l, j, k, i;
 int arraysize, arecord, alatitude, ja, ka, ia;
 int ist, ied;

/*************************************************************

 CALCULATE LEVEL SIZE AND ARRAY SIZE
 SET BASE DEPTH FOR ARRAY

**************************************************************/

 levelsize = *idim * *jdim;
 arraysize = *iparm * *jparm;
 ka = *k1-1;

 if ( *idims > *idime ) ll = 2;
 else ll=1;

/*************************************************************

 RUN THROUGH K (DEPTH) LEVELS

**************************************************************/

 for ( k = *ks; k <= *ke; k++ ) {

/*************************************************************

 CALCULATE DEPTH POINTER FOR FILE AND ARRAY
 SET BASE VALUE FOR ARRAY LATITUDE

**************************************************************/

  ka +=1;
  record = ( k-1 ) * levelsize;
  arecord = ( ka-1 ) * arraysize;
  ja = *jadim-1;

/*************************************************************

 RUN THROUGH J ( LATITUDE ) POINTS

**************************************************************/

  for ( j = *jdims; j <= *jdime; j++ ) {

/*************************************************************

 ADJUST LONGITUDE GRID STARTING, ENDING POINTS DEPENDENT ON
 WHETHER THE GREENWICH MERIDIAN HAS BEEN CROSSED OR NOT

**************************************************************/

   for ( l = 1; l <= ll; l++ ) {

    if ( ll == 2 ) {

     if ( l == 1 ) {
      ist= *idims;
      ied= *idim;
     }

     else {
      ist= 1;
      ied= *idime;
     }

    }

    else {
     ist= *idims;
     ied= *idime;
    }

/*************************************************************

 CALCULATE LATITUDE POINTER FOR FILE AND ARRAY
 SET BASE VALUE FOR ARRAY LONGITUDE

**************************************************************/

    if ( l == 1 ) {
    
     ja +=1;
     ia = *iadim-2;

    }

    latitude = *idim * (j-1) + ( ist-1 );
    alatitude = *iparm * (ja-1);

/*************************************************************

 GO TO CORRECT POINT IN FILE

**************************************************************/

    fseek( fp[*fn],(record+latitude)*sizeof(float),SEEK_SET);

/*************************************************************

 RUN THROUGH I (LONGITUDE) POINTS

**************************************************************/

    for ( i = ist -1; i < ied; i++ ) {

     ia +=1;

/*************************************************************

 READ DATA FROM FILE

**************************************************************/

     fread( (temp+arecord+alatitude+ia), sizeof(float),1,fp[(*fn)]);

    }

   }

  }

 } 

}