[goffice] Ignore invalid values while checking data order. [#744200]

[Jean Bréfort <jbrefort src gnome org>]

commit 6107b0c4deae40c562f5d24d9f59feef28061262
Author: Jean Brefort <jean brefort normalesup org>
Date:   Wed Feb 11 18:20:55 2015 +0100

    Ignore invalid values while checking data order. [#744200]

 ChangeLog                   |    5 +++++
 NEWS                        |    3 +++
 goffice/math/go-rangefunc.c |   32 ++++++++++++++++++++++++++------
 3 files changed, 34 insertions(+), 6 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 2ac7b28..f9d8233 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2015-02-11  Jean Brefort  <jean brefort normalesup org>
+
+       * goffice/math/go-rangefunc.c (go_range_increasing),
+       (go_range_decreasing): ignore nans. [#744200]
+
 2015-02-11  Morten Welinder  <terra gnome org>
 
        * goffice/canvas/goc-arc.c (prepare_draw_arrow): Protect oval
diff --git a/NEWS b/NEWS
index 5c5cb6a..5ba245e 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,8 @@
 goffice 0.10.21:
 
+Jean:
+       * Ignore invalid values while checking data order. [#744200]
+
 Morten:
        * Fix problem with linear solver.
        * Add arrow selector widget.
diff --git a/goffice/math/go-rangefunc.c b/goffice/math/go-rangefunc.c
index 2eb1567..63c61cb 100644
--- a/goffice/math/go-rangefunc.c
+++ b/goffice/math/go-rangefunc.c
@@ -307,22 +307,42 @@ SUFFIX(go_range_constant) (DOUBLE const *xs, int n)
 int
 SUFFIX(go_range_increasing) (DOUBLE const *xs, int n)
 {
-       int i;
+       int i = 0;
+       DOUBLE last;
        g_return_val_if_fail (n == 0 || xs != NULL, 0);
-       for (i = 1; i < n; i++)
-               if (xs[i - 1] >= xs[i])
+       while ( i < n && isnan (xs[i]))
+               i++;
+       if (i == n)
+               return 0;
+       last = xs[i];
+       for (i = i + 1; i < n; i++) {
+               if (isnan (xs[i]))
+                   continue;
+               if (last >= xs[i])
                        return 0;
+               last = xs[i];
+       }
        return 1;
 }
 
 int
 SUFFIX(go_range_decreasing) (DOUBLE const *xs, int n)
 {
-       int i;
+       int i = 0;
+       DOUBLE last;
        g_return_val_if_fail (n == 0 || xs != NULL, 0);
-       for (i = 1; i < n; i++)
-               if (xs[i - 1] <= xs[i])
+       while ( i < n &&  isnan (xs[i]))
+               i++;
+       if (i == n)
+               return 0;
+       last = xs[i];
+       for (i = i + 1; i < n; i++) {
+               if (isnan (xs[i]))
+                   continue;
+               if (last <= xs[i])
                        return 0;
+               last = xs[i];
+       }
        return 1;
 }