void dasec_c ( SpiceInt handle,
SpiceInt * n,
void * buffer,
SpiceBoolean * done )
Extract comments from the comment area of a binary DAS file.
Variable I/O Description
-------- --- --------------------------------------------------
handle I Handle of binary DAS file open with read access.
bufsiz I Maximum size, in lines, of buffer.
buflen I Line length associated with buffer.
n O Number of comments extracted from the DAS file.
buffer O Buffer in which extracted comments are placed.
done O Indicates whether all comments have been extracted.
handle The file handle of a binary DAS file which has been
opened with read access.
bufsiz The maximum number of comments that may be placed into
buffer. This would typically be the declared array size
for the C character string array passed into this
buflen is the common length of the strings in buffer, including the
n The number of comment lines extracted from the comment area
of the binary DAS file attached to handle. This number will
be <= bufsiz on output. If n == bufsiz and done !=
SPICETRUE then there are more comments left to extract. If
n == 0, then done == SPICETRUE, i.e., there were no
comments in the comment area. If there are comments in the
comment area, or comments remaining after the extraction
process has begun, n > 0, always.
buffer A list of at most bufsiz comments which have been
extracted from the comment area of the binary DAS
file attached to handle. buffer should be declared as
ConstSpiceChar buffer [bufsiz][buflen]
Each string in buffer is null-terminated.
done A boolean flag indicating whether or not all of the
comment lines from the comment area of the DAS file have
been read. This variable has the value SPICETRUE after the
last comment line has been read. It will have the value
If there are no comments in the comment area, this
variable will have the value SPICETRUE, and n == 0.
1) If the size of the output line buffer is is not positive,
the error SPICE(INVALIDARGUMENT) will be signaled.
2) If a comment line in a DAS file is longer than the length
of a character string array element of BUFFER, the error
SPICE(COMMENTTOOLONG) will be signaled.
3) If there is a mismatch between the number of comment
characters found and the number of comment characters
expected, the error SPICE(BADDASCOMMENTAREA) will be
4) If the binary DAS file attached to HANDLE is not open for
reading, an error will be signaled by a routine called by
5) If the input buffer pointer is null, the error SPICE(NULLPOINTER)
will be signaled.
6) If the input buffer string length buflen is not at least 2,
the error SPICE(STRINGTOOSHORT) will be signaled.
See argument handle in $ Detailed_Input.
Binary DAS files contain an area which is reserved for storing
annotations or descriptive textual information describing the data
contained in a file. This area is referred to as the "comment
area" of the file. The comment area of a DAS file is a line
oriented medium for storing textual information. The comment
area preserves any leading or embedded white space in the line(s)
of text which are stored, so that the appearance of the of
information will be unchanged when it is retrieved (extracted) at
some other time. Trailing blanks, however, are NOT preserved,
due to the way that character strings are represented in
standard Fortran 77.
This routine will read the comments from the comment area of
a binary DAS file, placing them into a line buffer. If the line
buffer is not large enough to hold the entire comment area,
the portion read will be returned to the caller, and the done
flag will be set to SPICEFALSE. This allows the comment area to be
read in "chunks," a buffer at a time. After all of the comment
lines have been read, the done flag will be set to SPICETRUE.
After all of the comments in DAS file have been read, the next
call to this routine will start reading comments at the start
of the comment area.
This routine can be used to "simultaneously" extract comments
from the comment areas of multiple binary DAS files.
1) The following example will extract the entire comment area of a
binary DAS file attached to HANDLE, displaying the comments on
the terminal screen.
int main( int argc, char ** argv )
#define LNSIZE 81
#define MAXBUF 25
SpiceChar buffer [MAXBUF][LNSIZE];
SpiceChar * filename;
filename = argv;
dasopr_ ( filename, &handle, (ftnlen)strlen(filename) );
done = SPICEFALSE;
while ( !done )
dasec_c( handle, MAXBUF, LNSIZE, &n, buffer, &done );
for ( i = 0; i < n; i++ )
printf ( "%s\n", buffer[i] );
return ( 0 );
1) The comment area may consist only of printing ASCII characters,
decimal values 32 - 126.
2) There is NO maximum length imposed on the significant portion
of a text line that may be placed into the comment area of a
DAS file. The maximum length of a line stored in the comment
area should be kept reasonable, so that they may be easily
extracted. A good value for this would be 255 characters, as
this can easily accommodate "screen width" lines as well as
long lines which may contain some other form of information.
N.J. Bachman (JPL)
K.R. Gehringer (JPL)
-CSPICE Version 1.1.0, 29-JUL-2015 (NJB)
Bug fix: removed semi-colon at end of the "if"
statement controlling execution of the call
to F2C_ConvertStrTrArr. This semi-colon turned
out to have no effect on the behavior of the
-CSPICE Version 1.0.0, 24-FEB-2003 (NJB) (KRG)
extract comments from a das file