1 files changed, 116 insertions, 0 deletions
diff --git a/funtest/evnext.c b/funtest/evnext.c
new file mode 100644
index 0000000..3050548
--- /dev/null
+++ b/funtest/evnext.c
@@ -0,0 +1,116 @@
+/*
+ *
+ * evnext.c -- example program for changing the time of an row to have
+ * the value from the next row
+ *
+ */
+
+#include <funtools.h>
+
+#define MAXROW 100
+
+typedef struct evstruct{
+  double time;
+} *Ev, EvRec;
+
+#ifdef ANSI_FUNC
+int 
+main (int argc, char **argv)
+#else
+main(argc, argv)
+     int argc;
+     char **argv;
+#endif
+{
+  int i;
+  int got, ogot;
+  char *oraw;
+  char *nraw;
+  char *null=NULL;
+  Ev ebuf, oebuf=NULL;
+  Ev ev, nev, oev;
+  Fun fun, fun2;
+
+  /* exit on gio errors */
+  setgerror(2);
+
+  /* make sure we have minimal arguments */
+  if( argc < 3 )
+    gerror(stderr, "usage: %s iname oname [columns]\n", argv[0]);
+
+  /* open file */
+  if( !(fun = FunOpen(argv[1], "r", NULL)) )
+    gerror(stderr, "could not FunOpen %s\n", argv[1]);
+
+  /* open the output FITS image, inheriting params from input */
+  if( !(fun2 = FunOpen(argv[2], "w", fun)) )
+    gerror(stderr, "could not FunOpen output file: %s\n", argv[2]);
+
+  /* specify columns we want */
+  got = FunColumnSelect(fun, sizeof(EvRec), "merge=update",
+			"time", "1D", "rw", FUN_OFFSET(Ev, time),
+			NULL);
+  /* activate specified columns -- these will be written to the output file */
+  if( argc >= 4 )
+    FunColumnActivate(fun, argv[3], NULL);
+
+  /* get rows */
+  while( (ebuf = (Ev)FunTableRowGet(fun, NULL, MAXROW, NULL, &got)) ){
+    /* process the last row from previous batch, if we have it */
+    if( oebuf ){
+      /* this is the old array of rows -- we point to the last one */
+      oev = oebuf+(ogot-1);
+      /* this is the new array of rows -- we point to the first one */
+      ev = ebuf;
+      /* change time value of old row to new row's value */
+      oev->time = ev->time;
+      /* now we have to write out this last row */
+      /* first, save pointer to the new raw data */
+      FunInfoGet(fun, FUN_RAWBUF, &nraw, 0);
+      /* put back old pointer so we merge it with last row */
+      FunInfoPut(fun, FUN_RAWBUF, &oraw, 0);
+      /* write out last row merging with its raw data */
+      /* (its arg 4 that tells funtools to merge with the last raw row) */
+      FunTableRowPut(fun2, oebuf, 1, ogot-1, NULL);
+      /* free up old raw data */
+      if( oraw ) free(oraw);
+      /* free up old user data */
+      if( oebuf ) free(oebuf);
+      /* finally, put back new raw data pointer, so we can process new batch */
+      FunInfoPut(fun, FUN_RAWBUF, &nraw, 0);
+    }
+    /* process the got-1 rows by replacing the time with time from
+       the succeeding row */
+    for(i=0; i<(got-1); i++){
+      /* point to the i'th row */
+      ev = ebuf+i;
+      nev = ebuf+(i+1);
+      ev->time = nev->time;
+    }
+    /* if we processed at least one row this time ... */
+    if( got > 1 ){
+      /* write out got-1 rows with the raw columns */
+      FunTableRowPut(fun2, (char *)ebuf, (got-1), 0, NULL);
+    }
+    /* if we have a "last" row to process next time ... */
+    if( got ){
+      /* save the user row for when we have the next batch */
+      oebuf = ebuf;
+      /* save pointer to raw data */
+      FunInfoGet(fun, FUN_RAWBUF, &oraw, 0);
+      /* null out rawbuf pointer so Funtools does not free it automatically */
+      FunInfoPut(fun, FUN_RAWBUF, &null, 0);
+      /* save old value of got */
+      ogot = got;
+    }
+  }
+
+  /* clean up last saved batch */
+  if( oraw ) free(oraw);
+  if( oebuf ) free(oebuf);
+
+  /* close and return */
+  FunClose(fun2);
+  FunClose(fun);
+  return(0);
+}