From 024f31843152d913684ee1b5557db9957f2e44d9 Mon Sep 17 00:00:00 2001
From: Russ Rew <russ@unidata.ucar.edu>
Date: Thu, 7 Jun 2012 18:14:02 +0000
Subject: [PATCH] Fixed bug NCF-175: ncdump -t incorrectly interpreting units
 attribute (such as "days") without a base time (such as "since 2007-01-01")
 as a time unit.

---
 libdispatch/nctime.c     |  1 -
 ncdump/nctime0.c         | 53 ++++++++++++++++++++++++++++++++++++++++
 ncdump/nctime0.h         |  1 +
 ncdump/ref_times.cdl     |  7 ++++++
 ncdump/tst_calendars.cdl |  7 ++++++
 5 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/libdispatch/nctime.c b/libdispatch/nctime.c
index 2cb55deed..e21d920c2 100644
--- a/libdispatch/nctime.c
+++ b/libdispatch/nctime.c
@@ -327,7 +327,6 @@ cdParseRelunits(cdCalenType timetype, char* relunits, cdUnitTime* unit, cdCompTi
 	} else {
 	    nconv = sscanf(relunits,"%s since %[^T]T%s",charunits,basetime_1,basetime_2);
 	}
-
 					     /* Get the units */
 	cdTrim(charunits,CD_MAX_RELUNITS);
 	if(!strncmp(charunits,"sec",3) || !strcmp(charunits,"s")){
diff --git a/ncdump/nctime0.c b/ncdump/nctime0.c
index 408e02960..e5e6ba36f 100644
--- a/ncdump/nctime0.c
+++ b/ncdump/nctime0.c
@@ -108,6 +108,55 @@ is_bounds_var(char *varname, int *pargrpidp, int *parvaridp) {
     return false;
 } 
 
+/* Test if attribute is of form required by cdtime: 
+ *     <time_unit> since <base_time>
+ * where
+ *     <time_unit>: 
+ */
+boolean
+is_valid_time_unit(const char *units) {
+	char charunits[CD_MAX_RELUNITS];
+	char basetime_1[CD_MAX_CHARTIME];
+	char basetime_2[CD_MAX_CHARTIME];
+	int nconv1, nconv2;
+	boolean okunit = false;
+
+	/* Allow ISO-8601 "T" date-time separator as well as blank separator */
+	nconv1 = sscanf(units,"%s since %[^T]T%s", charunits, basetime_1, basetime_2);
+	nconv2 = sscanf(units,"%s since %s %s", charunits, basetime_1, basetime_2);
+	if (!(nconv1 > 1 || nconv2 > 1))
+	    return false;
+	/* Check for unit compatible with cdtime library, no attempt
+	 * to enforce CF-compliance or udunits compliance here ... */
+	if(!strncmp(charunits,"sec",3) || !strcmp(charunits,"s")){
+	    okunit = true;
+	}
+	else if(!strncmp(charunits,"min",3) || !strcmp(charunits,"mn")){
+	    okunit = true;
+	}
+	else if(!strncmp(charunits,"hour",4) || !strcmp(charunits,"hr")){
+	    okunit = true;
+	}
+	else if(!strncmp(charunits,"day",3) || !strcmp(charunits,"dy")){
+	    okunit = true;
+	}
+	else if(!strncmp(charunits,"week",4) || !strcmp(charunits,"wk")){
+	    okunit = true;
+	}
+	else if(!strncmp(charunits,"month",5) || !strcmp(charunits,"mo")){
+	    okunit = true;
+	}
+	else if(!strncmp(charunits,"season",6)){
+	    okunit = true;
+	}
+	else if(!strncmp(charunits,"year",4) || !strcmp(charunits,"yr")){
+	    okunit = true;
+	}
+	if (!okunit)
+	    return false;
+	return true;
+}
+
 /* Return true only if this is a "bounds" attribute */
 boolean
 is_bounds_att(ncatt_t *attp) {
@@ -158,6 +207,10 @@ get_timeinfo(int ncid1, int varid1, ncvar_t *vp) {
 	units = emalloc(uatt.len + 1);
 	NC_CHECK(nc_get_att(ncid, varid, "units", units));
 	units[uatt.len] = '\0';
+	if(!is_valid_time_unit(units)) {
+	    free(units);
+	    return;
+	}
 	/* check for calendar attribute (not required even for time vars) */
 	vp->timeinfo = (timeinfo_t *)emalloc(sizeof(timeinfo_t));
 	memset((void*)vp->timeinfo,0,sizeof(timeinfo_t));
diff --git a/ncdump/nctime0.h b/ncdump/nctime0.h
index 17fce574a..91b4e92ba 100644
--- a/ncdump/nctime0.h
+++ b/ncdump/nctime0.h
@@ -8,6 +8,7 @@
 
 
 extern void insert_bounds_info(int ncid, int varid, ncatt_t att);
+extern int is_valid_time_unit(const char *units);
 extern int is_bounds_att(ncatt_t *attp);
 extern void get_timeinfo(int ncid, int varid, ncvar_t *vp);
 extern void print_att_times(int ncid, int varid, ncatt_t att);
diff --git a/ncdump/ref_times.cdl b/ncdump/ref_times.cdl
index 81a172b0e..40688d823 100644
--- a/ncdump/ref_times.cdl
+++ b/ncdump/ref_times.cdl
@@ -82,6 +82,11 @@ variables:
 		  // "1804-04-26", "1804-04-27", "1804-04-28", "1804-04-29",
 		  // "1804-04-30"
 	double t3_bnds(t3, bnds) ;
+	int t4 ;
+		t4:units = "days" ;
+		t4:att1 = 1 ;
+		t4:att2 = 5, 6 ;
+		t4:att3 = 7.125f, 8.75f ;
 data:
 
  t1_days = "2009-01-01" ;
@@ -132,4 +137,6 @@ data:
   "1804-01-10 12", "1804-01-11 12",
   "1804-01-11 12", "1804-01-12 12",
   "1804-01-12 12", "1804-01-13 12" ;
+
+ t4 = _ ;
 }
diff --git a/ncdump/tst_calendars.cdl b/ncdump/tst_calendars.cdl
index dc66983ca..1c10604a7 100644
--- a/ncdump/tst_calendars.cdl
+++ b/ncdump/tst_calendars.cdl
@@ -86,6 +86,13 @@ variables:
        t3:time5 = 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120 ;
     double t3_bnds(t3, bnds) ;  // no attributes, since a cell bounds variable
 
+// test -t bug fix, time unit without base time should not interpret numeric atts as times
+    int t4 ;
+       t4:units = "days" ;
+       t4:att1 = 1 ;
+       t4:att2 = 5, 6 ;
+       t4:att3 = 7.125f, 8.75f ;
+
 data:
    // Should all represent 2009-01-01 00:00:00
 	t1_days = 185900;