| dasadc |
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Table of contents
Procedure
DASADC ( DAS, add data, character )
SUBROUTINE DASADC ( HANDLE, N, BPOS, EPOS, DATA )
Abstract
Add character data to a DAS file.
Required_Reading
DAS
Keywords
ARRAY
ASSIGNMENT
DAS
FILES
Declarations
IMPLICIT NONE
INTEGER HANDLE
INTEGER N
INTEGER BPOS
INTEGER EPOS
CHARACTER*(*) DATA ( * )
Brief_I/O
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
HANDLE I DAS file handle.
N I Number of characters to add to file.
BPOS,
EPOS I Begin and end positions of substrings.
DATA I Array providing the set of substrings to be added
to the character data in the DAS file.
Detailed_Input
HANDLE is a file handle of a DAS file opened for writing.
N is the total number of characters to add to the specified
DAS file.
BPOS,
EPOS are the begin and end character positions that define the
substrings in each of the elements of the input array.
This routine writes the first N characters from the
specified set of substrings to the specified DAS file.
DATA is an array of strings, some portion of whose contents
are to be added to the specified DAS file. Specifically,
the first N characters of the substrings
DATA(I)(BPOS:EPOS), I = 1, ...
are appended to the character data in the file.
DATA must be declared at least as
CHARACTER*(EPOS) DATA ( R )
with the dimension R being at least
R = INT( ( N + SUBLEN - 1 ) / SUBLEN )
and SUBLEN, the length of each of the substrings in
the array to be added to the DAS file, being
SUBLEN = EPOS - BPOS + 1
The order of characters in the input substrings is
considered to increase from left to right within each
element of DATA, and to increase with the indices of the
elements of DATA.
Detailed_Output
None.
See $Particulars for a description of the effect of this routine.
Parameters
None.
Exceptions
1) If the input file handle is invalid, an error is signaled
by a routine in the call tree of this routine.
2) If EPOS or BPOS are outside of the range
[ 1, LEN( DATA(1) ) ]
or if EPOS < BPOS, the error SPICE(BADSUBSTRINGBOUNDS) is
signaled.
3) If the input count N is less than 1, no data will be
added to the specified DAS file.
4) If an I/O error occurs during the data addition attempted
by this routine, the error is signaled by a routine in the
call tree of this routine.
5) If N is greater than the number of characters in the
specified set of input substrings, the results of calling
this routine are unpredictable. This routine cannot
detect this error.
Files
See the description of the argument HANDLE in $Detailed_Input.
Particulars
DAS is a low-level format meant to store and transmit data. As
such, character data in DAS files are not interpreted by SPICELIB
DAS input or output routines. There are no limits on which
character values may be placed in the virtual character array of a
DAS file.
This routine adds character data to a DAS file by "appending" them
after any character data already in the file. The sense in which
the data are "appended" is that the data will occupy a range of
logical addresses for character data that immediately follow the
last logical address of a character that is occupied at the time
this routine is called. The diagram below illustrates this
addition:
+-------------------------+
| (already in use) | Character logical address 1
+-------------------------+
.
.
.
+-------------------------+ Last character logical address
| (already in use) | in use before call to DASADC
+-------------------------+
| DATA(1)(BPOS:BPOS) | First added character
+-------------------------+
| DATA(1)(BPOS+1:BPOS+1) |
+-------------------------+
.
.
.
+-------------------------+
| DATA(1)(EPOS:EPOS) |
+-------------------------+
| DATA(2)(BPOS:BPOS) |
+-------------------------+
.
.
.
+-------------------------+
| DATA(R)(C:C) | N'th added character---here R is
+-------------------------+
INT( (N+L-1)/L )
where L = EPOS - BPOS + 1, and
C is
BPOS + ( N - (R-1)*L ) - 1
The logical organization of the characters in the DAS file is
independent of the order of addition to the file or physical
location of any data of integer or double precision type.
The actual physical write operations that add the input array
DATA to the indicated DAS file may not take place before this
routine returns, since the DAS system buffers data that are
written as well as data that are read. In any case, the data
will be flushed to the file at the time the file is closed, if
not earlier. A physical write of all buffered records can be
forced by calling the SPICELIB routine DASWBR (DAS, write
buffered records).
In order to update character logical addresses that already
contain data, the SPICELIB routine DASUDC (DAS, update data,
character) should be used.
Examples
The numerical results shown for this example may differ across
platforms. The results depend on the SPICE kernels used as
input, the compiler and supporting libraries, and the machine
specific arithmetic implementation.
1) The following example demonstrates the capabilities of the
DAS character data routines. The reader should notice that
in these interfaces, the character data are treated not as
strings (or arrays of strings) but as a stream of single
characters: DAS character data are not limited to
human-readable text. For example, one can store images or
DEM data as DAS character data.
The example shows how to add a variable amount of character
data to a new DAS file, how to update some of the character
logical addresses within that file, and how to read that
data out to a different array.
Example code begins here.
PROGRAM DASADC_EX1
IMPLICIT NONE
C
C Local parameters.
C
CHARACTER*(*) FNAME
PARAMETER ( FNAME = 'dasadc_ex1.das' )
CHARACTER*(*) TYPE
PARAMETER ( TYPE = 'TEST' )
C
C Local variables.
C
CHARACTER*(22) CDATIN ( 3 )
CHARACTER*(30) CDATOU ( 10 )
INTEGER HANDLE
INTEGER I
DATA CDATOU / '..............................',
. '..............................',
. '..............................',
. '..............................',
. '..............................',
. '..............................',
. '..............................',
. '..............................',
. ' 1 2 3',
. '123456789012345678901234567890' /
C
C Open a new DAS file. Use the file name as the internal
C file name, and reserve no records for comments.
C
CALL DASONW ( FNAME, TYPE, FNAME, 0, HANDLE )
C
C Set the input data. Note that these data will be
C considered as a binary data stream: DAS character data
C are not limited to human-readable text. For example,
C one can store images or DEM data as DAS character data.
C
CDATIN ( 1 ) = '--F-345678901234567890'
CDATIN ( 2 ) = '--S-345678901234567890'
CDATIN ( 3 ) = '--T-IRDxxxxxxxxxxxxxxx'
C
C Add the last 20 characters of the first two elements
C of CDATIN, and the 3rd character from the third one.
C
CALL DASADC ( HANDLE, 41, 3, 22, CDATIN )
C
C Update the 10th, 20th and 30th character in the DAS
C file with a vertical bar.
C
DO I = 1, 3
CALL DASUDC ( HANDLE, I*10, I*10, 1, 1, '|' )
END DO
C
C Close the file.
C
CALL DASCLS ( HANDLE )
C
C Now verify the addition of data by opening the
C file for read access and retrieving the data.
C
CALL DASOPR ( FNAME, HANDLE )
C
C Read the 41 characters that we stored on the DAS
C file. Update the data on the CDATOU array, placing
C 6 characters on each element, starting from the
C 10th position.
C
CALL DASRDC ( HANDLE, 1, 41, 10, 15, CDATOU )
C
C Dump the data to the screen. Note that the last
C three lines should remain unmodified, and that
C only 5 characters will be written on the 7th line.
C
WRITE (*,*)
WRITE (*,*) 'Data from "', FNAME, '":'
WRITE (*,*)
DO I = 1, 10
WRITE (*,*) CDATOU(I)
END DO
C
C Close the file.
C
CALL DASCLS ( HANDLE )
END
When this program was executed on a Mac/Intel/gfortran/64-bit
platform, the output was:
Data from "dasadc_ex1.das":
.........F-3456...............
.........789|12...............
.........345678...............
.........9|S-34...............
.........56789|...............
.........123456...............
.........7890T................
..............................
1 2 3
123456789012345678901234567890
Note that after run completion, a new DAS file exists in the
output directory.
Restrictions
None.
Literature_References
None.
Author_and_Institution
N.J. Bachman (JPL)
J. Diaz del Rio (ODC Space)
K.R. Gehringer (JPL)
W.L. Taber (JPL)
Version
SPICELIB Version 1.3.0, 08-OCT-2021 (JDR) (NJB)
Added IMPLICIT NONE statement. Updated the code to avoid that
DASCUD is called with a negative number of character words
when the input count N is negative.
Made local variable RECORD a saved variable which is
initialized by a DATA statement.
Bug fix: added FAILED call after DASHFS call.
Edited the header to comply with NAIF standard.
Replaced example code with one that demonstrates the usage and
effect of all DAS character data routines.
Updated entries in the $Revisions section.
SPICELIB Version 1.2.0, 10-APR-2014 (NJB)
Deleted declarations of unused parameters.
Corrected header comments: routine that flushes
written, buffered records is DASWBR, not DASWUR.
SPICELIB Version 1.1.1, 19-DEC-1995 (NJB)
Corrected title of permuted index entry section.
SPICELIB Version 1.1.0, 12-MAY-1994 (KRG) (NJB)
Test of FAILED() added to loop termination condition.
Removed references to specific DAS file open routines in the
$Detailed_Input section of the header. This was done in order
to minimize documentation changes if the DAS open routines ever
change.
Modified the $Examples section to demonstrate the new ID word
format which includes a file type and to include a call to the
new routine DASONW, open new, which makes use of the file
type. Also, a variable for the type of the file to be created
was added.
SPICELIB Version 1.0.0, 11-NOV-1992 (NJB) (WLT)
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Fri Dec 31 18:36:10 2021