From: Stephen Dolan <mu@netsoc.tcd.ie>
Date: Mon, 18 Jan 2016 10:56:54 +0000 (+0000)
Subject: Make jv_sort stable regardless of qsort details.
X-Git-Tag: jq-1.6rc1~107
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7835a724d65708f4511e5d26c5ae9a1a5c1da576;p=jq

Make jv_sort stable regardless of qsort details.
---

diff --git a/src/jv_aux.c b/src/jv_aux.c
index 1750013..db2e0ef 100644
--- a/src/jv_aux.c
+++ b/src/jv_aux.c
@@ -571,14 +571,15 @@ int jv_cmp(jv a, jv b) {
 struct sort_entry {
   jv object;
   jv key;
+  int index;
 };
 
 static int sort_cmp(const void* pa, const void* pb) {
   const struct sort_entry* a = pa;
   const struct sort_entry* b = pb;
   int r = jv_cmp(jv_copy(a->key), jv_copy(b->key));
-  // comparing by address if r == 0 makes the sort stable
-  return r ? r : (int)(a - b);
+  // comparing by index if r == 0 makes the sort stable
+  return r ? r : (a->index - b->index);
 }
 
 static struct sort_entry* sort_items(jv objects, jv keys) {
@@ -590,6 +591,7 @@ static struct sort_entry* sort_items(jv objects, jv keys) {
   for (int i=0; i<n; i++) {
     entries[i].object = jv_array_get(jv_copy(objects), i);
     entries[i].key = jv_array_get(jv_copy(keys), i);
+    entries[i].index = i;
   }
   jv_free(objects);
   jv_free(keys);