From 2efa285db72cc27e153c5684949fa73a30b5aee5 Mon Sep 17 00:00:00 2001
From: Bborie Park <bkpark at ucdavis.edu>
Date: Fri, 27 Jan 2012 21:05:32 +0000
Subject: [PATCH] Fixed segfault caused by an empty quantile linked list being
 used to get the quantile's value.  Ticket is #1506.

git-svn-id: http://svn.osgeo.org/postgis/trunk@8949 b70326c6-7e19-0410-871a-916f4a2858ee
---
 raster/rt_core/rt_api.c | 13 ++++++++++---
 raster/rt_core/rt_api.h |  1 +
 raster/rt_pg/rt_pg.c    |  9 +++++++--
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/raster/rt_core/rt_api.c b/raster/rt_core/rt_api.c
index 10a4415f2..5895577f1 100644
--- a/raster/rt_core/rt_api.c
+++ b/raster/rt_core/rt_api.c
@@ -3020,7 +3020,7 @@ rt_band_get_quantiles_stream(rt_band band,
 		}
 		quicksort(quantiles, quantiles + quantiles_count - 1);
 
-		/* initialize rt_quantile */
+		/* initialize linked-list set */
 		*qlls_count = quantiles_count * 2;
 		RASTER_DEBUGF(4, "qlls_count = %d", *qlls_count);
 		*qlls = rtalloc(sizeof(struct quantile_llist) * *qlls_count);
@@ -3433,6 +3433,9 @@ rt_band_get_quantiles_stream(rt_band band,
 				}
 
 			}
+			else {
+				RASTER_DEBUGF(5, "skipping value at (x, y) = (%d, %d)", x, y);
+			}
 
 			z++;
 		}
@@ -3461,6 +3464,11 @@ rt_band_get_quantiles_stream(rt_band band,
 		RASTER_DEBUGF(5, "qll: (head, tail) = (%p, %p)", qll->head, qll->tail);
 
 		rtn[k].quantile = qll->quantile;
+		rtn[k].has_value = 0;
+
+		/* check that qll->head and qll->tail have value */
+		if (qll->head == NULL || qll->tail == NULL)
+			continue;
 
 		/* AL-GEQ */
 		if (qll->algeq)
@@ -3469,8 +3477,6 @@ rt_band_get_quantiles_stream(rt_band band,
 		else
 			qle = qll->tail;
 
-		RASTER_DEBUGF(5, "qle: (value, count) = (%f, %d)", qle->value, qle->count);
-
 		exists = 0;
 		for (j = i + 1; j < *qlls_count; j++) {
 			if (FLT_EQ((*qlls)[j].quantile, qll->quantile)) {
@@ -3499,6 +3505,7 @@ rt_band_get_quantiles_stream(rt_band band,
 		else {
 			rtn[k].value = qle->value;
 		}
+		rtn[k].has_value = 1;
 		RASTER_DEBUGF(3, "(quantile, value) = (%f, %f)\n\n", rtn[k].quantile, rtn[k].value);
 
 		k++;
diff --git a/raster/rt_core/rt_api.h b/raster/rt_core/rt_api.h
index d77c1988d..9d6ab6ad9 100644
--- a/raster/rt_core/rt_api.h
+++ b/raster/rt_core/rt_api.h
@@ -1490,6 +1490,7 @@ struct rt_histogram_t {
 struct rt_quantile_t {
 	double quantile;
 	double value;
+	uint32_t has_value;
 };
 
 /* listed-list structures for rt_band_get_quantiles_stream */
diff --git a/raster/rt_pg/rt_pg.c b/raster/rt_pg/rt_pg.c
index 393c2da8c..87606d62c 100644
--- a/raster/rt_pg/rt_pg.c
+++ b/raster/rt_pg/rt_pg.c
@@ -5333,7 +5333,9 @@ Datum RASTER_quantileCoverage(PG_FUNCTION_ARGS)
 		covquant2 = SPI_palloc(sizeof(struct rt_quantile_t) * count);
 		for (i = 0; i < count; i++) {
 			covquant2[i].quantile = covquant[i].quantile;
-			covquant2[i].value = covquant[i].value;
+			covquant2[i].has_value = covquant[i].has_value;
+			if (covquant2[i].has_value)
+				covquant2[i].value = covquant[i].value;
 		}
 
 		if (NULL != covquant) pfree(covquant);
@@ -5392,7 +5394,10 @@ Datum RASTER_quantileCoverage(PG_FUNCTION_ARGS)
 		memset(nulls, FALSE, values_length);
 
 		values[0] = Float8GetDatum(covquant2[call_cntr].quantile);
-		values[1] = Float8GetDatum(covquant2[call_cntr].value);
+		if (covquant2[call_cntr].has_value)
+			values[1] = Float8GetDatum(covquant2[call_cntr].value);
+		else
+			nulls[1] = TRUE;
 
 		/* build a tuple */
 		tuple = heap_form_tuple(tupdesc, values, nulls);
-- 
2.40.0