dafgsr_c |
Table of contents
Proceduredafgsr_c ( DAF, get summary/descriptor record ) void dafgsr_c ( SpiceInt handle, SpiceInt recno, SpiceInt begin, SpiceInt end, SpiceDouble * data, SpiceBoolean * found ) AbstractRead a portion of the contents of a summary record in a DAF file. Required_ReadingDAF KeywordsFILES Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- handle I Handle of DAF. recno I Record number. begin I First word to read from record. end I Last word to read from record. data O Contents of record. found O SPICETRUE if record is found. Detailed_Inputhandle is the handle associated with a DAF. recno is the record number of a particular double precision record within the DAF, whose contents are to be read. DAF record numbers start at 1. begin is the first word in the specified record to be returned. Word numbers range from 1 to 128. end is the final word in the specified record to be returned. Word numbers range from 1 to 128. Detailed_Outputdata contains the specified portion (from `begin' to `end', inclusive) of the specified record from the specified file. found is SPICETRUE when the specified record is found, and is SPICEFALSE otherwise. ParametersNone. Exceptions1) If `handle' does not belong to any file that is currently open, an error is signaled by a routine in the call tree of this routine. 2) If an error occurs while reading the record, the error is signaled by a routine in the call tree of this routine. 3) Bad values for `begin' and `end' ( begin < 1, end > 128, end < begin ) are not diagnosed. See -Particulars and -Restrictions for the effect of this routine in this case. FilesThe input `handle' must refer to a DAF file that is open for read or write access. Particularsdafgsr_c checks the DAF record buffer to see if the requested record can be returned without actually reading it from external storage. If not, it reads the record and stores it in the buffer, typically removing another record from the buffer as a result. Once in the buffer, the specified portion of the record is returned, using the following control loop. for ( j = 0, i = max(1,begin); i <= min(128,end); i++, j++ ) { data[j] = buffered_DAF_record[i]; } Therefore bad values for `begin' and `end' (begin < 1, end < begin, etc.) are not signaled as errors, but result in the actions implied by the above. ExamplesThe following code fragment illustrates one way that dafgsr_c and dafwdr_ can be used to update part of a summary record. If the record does not yet exist, we can assume that it is filled with zeros. #include "SpiceUsr.h" #include "SpiceZfc.h" SpiceInt size = 128; SpiceInt recno; SpiceInt handle; . . . dafgsr_c ( handle, recno, 1, 128, drec, &found ); if ( !found ) { cleard_ ( &size, drec ); } for ( i = first; i <= last; i++ ) { drec[i] = new_value[i]; } dafwdr_ ( &handle, &recno, drec ); Note that since only entire records may be written using dafwdr_, the entire record needs to be read also. Restrictions1) Bad values for `begin' and `end' ( begin < 1, end > 128, end < begin ) are not signaled as errors. The effects of such assignments on the returned data are defined by the following control structure: for ( j = 0, i = max(1,begin); i <= min(128,end); i++, j++ ) { data[j] = buffered_DAF_record[i]; } Literature_ReferencesNone. Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) F.S. Turner (JPL) Version-CSPICE Version 1.1.0, 08-AUG-2021 (JDR) (NJB) Bug fix: now the number of records read is not incremented once it reaches intmax_c, if it does. Edited the header to comply with NAIF standard. Updated -Detailed_Input, -Exceptions, -Particulars and -Restrictions sections. -CSPICE Version 1.0.0, 17-JUN-2009 (NJB) (FST) Index_Entriesread DAF summary record Link to routine dafgsr_c source file dafgsr_c.c |
Fri Dec 31 18:41:03 2021