From b059b6d2d19c81b4b72b37ef801a0efd6d379619 Mon Sep 17 00:00:00 2001
From: Ed Hartnett <edwardjameshartnett@gmail.com>
Date: Wed, 26 Jun 2019 07:06:54 -0600
Subject: [PATCH] now find_region() returns error code, and takes pointer to
 regionlen as a parameter

---
 src/clib/pio_internal.h  |  4 ++--
 src/clib/pio_rearrange.c | 26 ++++++++++++++------------
 tests/cunit/test_rearr.c |  3 ++-
 3 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/src/clib/pio_internal.h b/src/clib/pio_internal.h
index 4f3a3aebcbc..6c6146e702a 100644
--- a/src/clib/pio_internal.h
+++ b/src/clib/pio_internal.h
@@ -237,8 +237,8 @@ extern "C" {
     int alloc_region2(iosystem_desc_t *ios, int ndims, io_region **region);
 
     /* Set start and count so that they describe the first region in map.*/
-    PIO_Offset find_region(int ndims, const int *gdims, int maplen, const PIO_Offset *map,
-                           PIO_Offset *start, PIO_Offset *count);
+    int find_region(int ndims, const int *gdims, int maplen, const PIO_Offset *map,
+                    PIO_Offset *start, PIO_Offset *count, PIO_Offset *regionlen);
 
     /* Calculate start and count regions for the subset rearranger. */
     int get_regions(int ndims, const int *gdimlen, int maplen, const PIO_Offset *map,
diff --git a/src/clib/pio_rearrange.c b/src/clib/pio_rearrange.c
index 0638dfcbdee..d2f3b385e29 100644
--- a/src/clib/pio_rearrange.c
+++ b/src/clib/pio_rearrange.c
@@ -150,20 +150,21 @@ expand_region(int dim, const int *gdimlen, int maplen, const PIO_Offset *map,
  * found region.
  * @param count array (length ndims) that will get counts of found
  * region.
- * @returns length of the region found.
+ * @param regionlen pointer that gets the length of the region found.
+ * @returns 0 for success, error code otherwise.
  * @author Jim Edwards
  */
-PIO_Offset
+int
 find_region(int ndims, const int *gdimlen, int maplen, const PIO_Offset *map,
-            PIO_Offset *start, PIO_Offset *count)
+            PIO_Offset *start, PIO_Offset *count, PIO_Offset *regionlen)
 {
-    PIO_Offset regionlen = 1;
-
     /* Check inputs. */
-    pioassert(ndims > 0 && gdimlen && maplen > 0 && map && start && count,
-              "invalid input", __FILE__, __LINE__);
+    pioassert(ndims > 0 && gdimlen && maplen > 0 && map && start && count &&
+              regionlen, "invalid input", __FILE__, __LINE__);
     LOG((2, "find_region ndims = %d maplen = %d", ndims, maplen));
 
+    *regionlen = 1;
+
     int max_size[ndims];
 
     /* Convert the index which is the first element of map into global
@@ -187,9 +188,9 @@ find_region(int ndims, const int *gdimlen, int maplen, const PIO_Offset *map,
 
     /* Calculate the number of data elements in this region. */
     for (int dim = 0; dim < ndims; dim++)
-        regionlen *= count[dim];
+        *regionlen *= count[dim];
 
-    return regionlen;
+    return PIO_NOERR;
 }
 
 /**
@@ -1845,7 +1846,7 @@ get_regions(int ndims, const int *gdimlen, int maplen, const PIO_Offset *map,
             int *maxregions, io_region *firstregion)
 {
     int nmaplen = 0;
-    int regionlen;
+    PIO_Offset regionlen;
     io_region *region;
     int ret;
 
@@ -1879,8 +1880,9 @@ get_regions(int ndims, const int *gdimlen, int maplen, const PIO_Offset *map,
             region->count[i] = 1;
 
         /* Set start/count to describe first region in map. */
-        regionlen = find_region(ndims, gdimlen, maplen-nmaplen,
-                                &map[nmaplen], region->start, region->count);
+        if ((ret = find_region(ndims, gdimlen, maplen-nmaplen,
+                               &map[nmaplen], region->start, region->count, &regionlen)))
+            return ret;
         pioassert(region->start[0] >= 0, "failed to find region", __FILE__, __LINE__);
 
         nmaplen = nmaplen + regionlen;
diff --git a/tests/cunit/test_rearr.c b/tests/cunit/test_rearr.c
index 3f29022713a..9c653bfdd84 100644
--- a/tests/cunit/test_rearr.c
+++ b/tests/cunit/test_rearr.c
@@ -450,7 +450,8 @@ int test_find_region()
     PIO_Offset regionlen;
 
     /* Call the function we are testing. */
-    regionlen = find_region(ndims, gdimlen, maplen, map, start, count);
+    if (find_region(ndims, gdimlen, maplen, map, start, count, &regionlen))
+        return ERR_WRONG;
 
     /* Check results. */
     if (regionlen != 1 || start[0] != 0 || count[0] != 1)