[Pspp-cvs] pspp/src/data casefile.c

[Ben Pfaff]

CVSROOT:        /cvsroot/pspp
Module name:    pspp
Changes by:     Ben Pfaff <blp> 06/06/08 04:32:58

Modified files:
        src/data       : casefile.c 

Log message:
        Update comment to reflect availability of random casereaders.

CVSWeb URLs:
http://cvs.savannah.gnu.org/viewcvs/pspp/src/data/casefile.c?cvsroot=pspp&r1=1.10&r2=1.11

Patches:
Index: casefile.c
===================================================================
RCS file: /cvsroot/pspp/pspp/src/data/casefile.c,v
retrieving revision 1.10
retrieving revision 1.11
diff -u -b -r1.10 -r1.11
--- casefile.c  7 Jun 2006 01:48:47 -0000       1.10
+++ casefile.c  8 Jun 2006 04:32:58 -0000       1.11
@@ -66,10 +66,10 @@
           during the reading phase.  Each casereader has an
           independent position in the casefile.
 
-          Casereaders may only move forward.  They cannot move
-          backward to arbitrary records or seek randomly.
-          Cloning casereaders is possible, but it is not yet
-          implemented.
+          Ordinary casereaders may only move forward.  They
+          cannot move backward to arbitrary records or seek
+          randomly.  Cloning casereaders is possible, but it is
+          not yet implemented.
 
           Use casefile_get_reader() to create a casereader for
           use in phase 2.  This also transitions from phase 1 to
@@ -80,6 +80,12 @@
           a case from a casereader.  Use casereader_destroy() to
           discard a casereader when it is no longer needed.
 
+          "Random" casereaders, which support a seek operation,
+          may also be created.  These should not, generally, be
+          used for statistical procedures, because random access
+          is much slower than sequential access.  They are
+          intended for use by the GUI.
+
        3. Destruction.  This phase is optional.  The casefile is
           also read with casereaders in this phase, but the
           ability to create new casereaders is curtailed.