Ubuntu Manpage: ms_selection - Routines to manage and use data selection lists.

NAME

       ms_selection - Routines to manage and use data selection lists.

SYNOPSIS

       #include <libmseed.h>

       Selections *ms_matchselect ( Selections *selections, char *srcname,
                                    hptime_t starttime, hptime_t endtime,
                                    SelectTime **ppselecttime );

       Selections *msr_matchselect ( Selections *selections, MSRecord *msr,
                                     SelectTime **ppselecttime );

       int  ms_addselect ( Selections **ppselections, char *srcname,
                          hptime_t starttime, hptime_t endtime );

       int  ms_addselect_comp ( Selections **ppselections, char *net,
                                char *sta, char *loc, char *chan, char *qual,
                                hptime_t starttime, hptime_t endtime );

       int  ms_readselectionsfile ( Selections **ppselections, char *filename );

       void ms_freeselections ( Selections *selections );

       void ms_printselections ( Selections *selections );

DESCRIPTION

These routines serve as a convienence facility for creating a list of data selections and using it to
match data. The selection criteria are the srcname and optional start and end times. The srcname
components in a selection may contain globbing characters for matching (wildcards, character range,
etc.). A srcname is generally composed of network, station, location, channel and optional quality
components; normally these are created with msr_srcname(3) and mst_srcname(3).

ms_matchselect checks for an entry in the selections list that matches the supplied srcname and
optionally starttime and endtime. The start and/or end times can be set to HTPERROR to mean "any" time.
A selection will match the specified time range if there is any overlap in time coverage. If the
ppselecttime pointer is not NULL it will be set to the matching SelectTime entry.

msr_matchselect is a simple wrapper to call ms_matchselect using the details from a specified MSRecord.

ms_addselect adds a selection entry to the selections list based on the rcname and the starttime and
endtime boundaries. The source name components may contain globbing characters for matching including
wildcards and character sets, see SRCNAME MATCHING below. Note that the ppselections is a pointer to a
pointer, if the secondary pointer has not been allocated (i.e. the list is empty) the first entry will be
created and the primary pointer updated.

ms_addselect_comp is a wrapper of ms_addselect used to add a selection entry to the selections list. The
net, sta, loc, chan and qual source name components are used to create a srcname. The name components
may contain globbing characters for matching including wildcards and character sets, see SRCNAME MATCHING
below. If a name component is not specified a wildard matching all entries will be subsituted, i.e.
net==NULL will be interpreted to match all network codes. As a special case a loc value of "--" will be
translated to and empty string to match the srcname representation of a blank (space-space) location ID.

ms_readselectionsfile reads a file containing a list of selections and adds them to the specified
selections list. As with ms_addselect if the selections list is empty it will be created. For more
details see the SELECTION FILE section below.

ms_freeselections frees all memory associated with selections.

ms_printselections prints all of the entries in the selections list using the ms_log() facility.

RETURN VALUES

       The  ms_matchselect  and  msr_matchselect  routines  return a pointer to the matching Selections entry on
       success and NULL when no match was found.  These routines will also set the ppselecttime pointer  to  the
       matching SelectTime entry if supplied.

       ms_addselect and ms_addselect_comp return 0 on success and -1 on error.

       ms_readselectionsfile returns the number of selections added to the list or -1 on error.

SELECTION FILE

       A  selection  file  is  used  to match input data records based on network, station, location and channel
       information.  Optionally a quality and time range may also be specified for more refined selection.   The
       non-time  fields  may  use  the  '*'  wildcard to match multiple characters and the '?' wildcard to match
       single characters.  Character sets may also be used, for example '[ENZ]' will match either  E,  N  or  Z.
       The '#' character indicates the remaining portion of the line will be ignored.

       Example selection file entries (the first four fields are required)
       #net sta  loc  chan  qual  start             end
       IU   ANMO *    BH?
       II   *    *    *     Q
       IU   COLA 00   LH[ENZ] R
       IU   COLA 00   LHZ   *     2008,100,10,00,00 2008,100,10,30,00

SRCNAME MATCHING

       Entries  in  a  Selections list include a "source name" (srcname) string to represent matching parameters
       for network, station, location, channel and optionally the quality name components.  Each name  component
       may contain globbing characters to match more than one unique srcname.

       Valid glob patterns include:
          *       matches zero or more characters
          ?       matches any single character
          [set]   matches any character in the set
          [^set]  matches any character NOT in the set
                  where a set is a group of characters or ranges. a range
                  is written as two characters separated with a hyphen:
                  a-z denotes all characters between a to z inclusive.
          [-set]  set matches a literal hyphen and any character in the set
          []set]  matches a literal close bracket and any character in the set

          char    matches itself except where char is '*' or '?' or '['

        examples:
          a*c             ac abc abbc ...
          a?c             acc abc aXc ...
          a[a-z]c         aac abc acc ...
          a[-a-z]c        a-c aac abc ...

EXAMPLE USAGE

       The  primary  intention  of the Selections list facility is to limit data to a specific selection as it's
       read into a program.  This is illustrated below.

       main() {
         MSRecord *msr = NULL;
         Selections *selections = NULL;
         hptime_t starttime;
         hptime_t endtime;
         int retcode;

         ms_addselect (&selections, "IU_*_*_LH?_?", HPTERROR, HPTERROR);

         starttime = timestr2hptime ("2009/1/15 00:00:00.00");
         endtime = timestr2hptime ("2009/1/31 23:59:59.99");
         ms_addselect (&selections, "IU_ANMO_00_LH?_?", starttime, endtime);

         while ( (retcode = ms_readmsr (&msr, filename, 0, NULL, NULL, 1, 0, verbose)) == MS_NOERROR )
           {
              /* Print details if data record matches selection criteria */
              if ( msr_matchselect (selections, msr, NULL) )
                {
                  msr_print (msr, verbose);
                }
           }

         if ( retcode != MS_ENDOFFILE )
           ms_log (2, "Error reading input file %s: %s\n",
                   filename, ms_errorstr(retcode));

         /* Cleanup memory and close file */
         ms_readmsr (&msr, NULL, 0, NULL, NULL, 0, 0, verbose);
       } /* End of main() */

       The following two calls are equivalent:
         ms_addselect (&selections, "IU_ANMO_00_LH?_?", starttime, endtime);
         ms_addselect_comp (&selections, "IU", "ANMO", "00", "LH?", "?", startime, endtime);

       As a further convienence usage of ms_readselectionsfile() would allow the selections to be specified in a
       simple ASCII file and avoid the need to directly call ms_addselect().

AUTHOR

       Chad Trabant
       IRIS Data Management Center