PRO test_num_3d_arr, data, status, xsize, ysize, zsize, dtype

; Description: This module tests that the parameter "data" contains a three-dimensional array. 
;              In other words, it checks that "data" is non-empty, contains numbers of any of 
;              the types BYTE, INTEGER, LONG, FLOAT, DOUBLE, UINT, ULONG, LONG64 or ULONG64, 
;              and has exactly three dimensions. If the module finds that "data" does indeed 
;              contain a three-dimensional array, then it also determines the array size and 
;              saves this information in the parameters "xsize", "ysize", and "zsize". Finally,
;              the module also returns the IDL type code of the parameter "data".
;
; Input Parameters:
;
;   data - ANY - The parameter to be tested whether or not it satisfies the properties that a 
;                three-dimensional array of number data would have.
;
; Output Parameters:
;
;   status - INTEGER - The parameter "status" is set to "1" if the parameter "data" is a
;                      non-empty array of numbers of any of the types BYTE, INTEGER, LONG, 
;                      FLOAT, DOUBLE, UINT, ULONG, LONG64 or ULONG64, with exactly three 
;                      dimensions. Otherwise, the module sets the value of "status" to "0".
;   xsize - LONG - The array size along the x-axis. This parameter is only calculated if 
;                  "status" is set to "1".
;   ysize - LONG - The array size along the y-axis. This parameter is only calculated if 
;                  "status" is set to "1".
;   zsize - LONG - The array size along the z-axis. This parameter is only calculated if 
;                  "status" is set to "1".
;   dtype - INTEGER - The IDL type code of the data values stored in "data". Note that IDL 
;                     type codes of 1, 2, 3, 4, 5, 12, 13, 14 and 15 correspond to variable 
;                     types of BYTE, INTEGER, LONG, FLOAT, DOUBLE, UINT, ULONG, LONG64 and 
;                     ULONG64, respectively.
;
; Author: Dan Bramich (dmb@ing.iac.es)
;
; History:
;
;   11/12/2008 - Module created (dmb)

;Determine the IDL type code for "data"

;Check that "data" has three dimensions

;If "data" is three-dimensional and contains numbers of any of the types BYTE, INTEGER, LONG, FLOAT,
;DOUBLE, UINT, ULONG, LONG64 or ULONG64, then set the value of "status" to "1" and determine the
;array size