From 34cb3b49aed3f145ccf68f083041e493cc5fc924 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@cs.stanford.edu>
Date: Sat, 9 Jan 2021 18:01:42 -0800
Subject: [PATCH] pivot-table: Always put footnote markers in sorted order.

This is compatible behavior.
---
 src/output/pivot-table.c           | 23 +++++++++++++++++++++++
 src/output/pivot-table.h           |  1 +
 src/output/spv/spv-light-decoder.c |  1 +
 3 files changed, 25 insertions(+)

diff --git a/src/output/pivot-table.c b/src/output/pivot-table.c
index 369ab63525..85ac16d09c 100644
--- a/src/output/pivot-table.c
+++ b/src/output/pivot-table.c
@@ -2859,6 +2859,29 @@ pivot_value_add_footnote (struct pivot_value *v,
   v->footnote_indexes = xrealloc (
     v->footnote_indexes, (v->n_footnotes + 1) * sizeof *v->footnote_indexes);
   v->footnote_indexes[v->n_footnotes++] = footnote->idx;
+  pivot_value_sort_footnotes (v);
+}
+
+static int
+compare_footnote_indexes (const void *a_, const void *b_)
+{
+  const size_t *ap = a_;
+  const size_t *bp = b_;
+  size_t a = *ap;
+  size_t b = *bp;
+  return a < b ? -1 : a > b;
+}
+
+/* Sorts the footnote references in V in the standard ascending order.
+
+   This is only necessary if code adds (plural) footnotes to a pivot_value by
+   itself, because pivot_value_add_footnote() does it automatically. */
+void
+pivot_value_sort_footnotes (struct pivot_value *v)
+{
+  if (v->n_footnotes > 1)
+    qsort (v->footnote_indexes, v->n_footnotes, sizeof *v->footnote_indexes,
+           compare_footnote_indexes);
 }
 
 /* If VALUE is a numeric value, and RC is a result class such as
diff --git a/src/output/pivot-table.h b/src/output/pivot-table.h
index 0c89725a24..2a5d8467f8 100644
--- a/src/output/pivot-table.h
+++ b/src/output/pivot-table.h
@@ -749,6 +749,7 @@ struct pivot_value *pivot_value_new_user_text_nocopy (char *);
 
 /* Footnotes. */
 void pivot_value_add_footnote (struct pivot_value *, const struct pivot_footnote *);
+void pivot_value_sort_footnotes (struct pivot_value *);
 
 /* Numeric formats. */
 void pivot_value_set_rc (const struct pivot_table *, struct pivot_value *,
diff --git a/src/output/spv/spv-light-decoder.c b/src/output/spv/spv-light-decoder.c
index 20f7afa11b..ce5bd067c9 100644
--- a/src/output/spv/spv-light-decoder.c
+++ b/src/output/spv/spv-light-decoder.c
@@ -415,6 +415,7 @@ decode_spvlb_value (const struct pivot_table *table,
 
               out->footnote_indexes[out->n_footnotes++] = idx;
             }
+          pivot_value_sort_footnotes (out);
         }
 
       if (vm->style_pair)
-- 
2.30.2