889fcdc1d8d6d606c00d501b2c5e71a92a877280
angie
  Wed Oct 3 14:33:39 2012 -0700
If the .bb has no rows for the current chromosome, omit example row display.It would be nicer to just grab the first rows from the bigBed file in this case... don't have time today.

diff --git src/hg/hgTables/bigBed.c src/hg/hgTables/bigBed.c
index 3e5ca72..ac61621 100644
--- src/hg/hgTables/bigBed.c
+++ src/hg/hgTables/bigBed.c
@@ -316,79 +316,88 @@
 
 hPrintf("<B>Database:</B> %s", database);
 hPrintf("&nbsp;&nbsp;&nbsp;&nbsp;<B>Primary Table:</B> %s<br>", table);
 hPrintf("<B>Big Bed File:</B> %s", fileName);
 if (bbi->version >= 2)
     {
     hPrintf("<BR><B>Item Count:</B> ");
     printLongWithCommas(stdout, bigBedItemCount(bbi));
     }
 hPrintf("<BR>\n");
 hPrintf("<B>Format description:</B> %s<BR>", as->comment);
 
 /* Put up table that describes fields. */
 hTableStart();
 hPrintf("<TR><TH>field</TH>");
+if (ivList != NULL)
 hPrintf("<TH>example</TH>");
 hPrintf("<TH>description</TH> ");
 puts("</TR>\n");
 struct asColumn *col;
 int colCount = 0;
 char *row[bbi->fieldCount];
 char startBuf[16], endBuf[16];
+if (ivList != NULL)
+    {
 char *dupeRest = lmCloneString(lm, ivList->rest);	/* Manage rest-stomping side-effect */
 bigBedIntervalToRow(ivList, chromList->name, startBuf, endBuf, row, bbi->fieldCount);
 ivList->rest = dupeRest;
+    }
 for (col = as->columnList; col != NULL; col = col->next)
     {
     hPrintf("<TR><TD><TT>%s</TT></TD>", col->name);
+    if (ivList != NULL)
     hPrintf("<TD>%s</TD>", row[colCount]);
     hPrintf("<TD>%s</TD></TR>", col->comment);
     ++colCount;
     }
 
 /* If more fields than descriptions put up minimally helpful info (at least has example). */
 for ( ; colCount < bbi->fieldCount; ++colCount)
     {
     hPrintf("<TR><TD><TT>column%d</TT></TD>", colCount+1);
+    if (ivList != NULL)
     hPrintf("<TD>%s</TD>", row[colCount]);
     hPrintf("<TD>n/a</TD></TR>\n");
     }
 hTableEnd();
 
 
+if (ivList != NULL)
+    {
 /* Put up another section with sample rows. */
 webNewSection("Sample Rows");
 hTableStart();
 
 /* Print field names as column headers for example */
 hPrintf("<TR>");
 int colIx = 0;
 for (col = as->columnList; col != NULL; col = col->next)
     {
     hPrintf("<TH>%s</TH>", col->name);
     ++colIx;
     }
 for (; colIx < colCount; ++colIx)
     hPrintf("<TH>column%d</TH>", colIx+1);
 hPrintf("</TR>\n");
 
 /* Print sample lines. */
 struct bigBedInterval *iv;
 for (iv=ivList; iv != NULL; iv = iv->next)
     {
     bigBedIntervalToRow(iv, chromList->name, startBuf, endBuf, row, bbi->fieldCount);
     hPrintf("<TR>");
     for (colIx=0; colIx<colCount; ++colIx)
         {
 	writeHtmlCell(row[colIx]);
 	}
     hPrintf("</TR>\n");
     }
 hTableEnd();
+    }
 printTrackHtml(tdb);
 /* Clean up and go home. */
 lmCleanup(&lm);
 bbiFileClose(&bbi);
 freeMem(fileName);
 hFreeConn(&conn);
 }