[PATCH 6/6] variant: produce stable results

[Akim Demaille]

Improve the output by ensuring a well defined order for type switches.

* src/uniqstr.h: Style changes for macro arguments.
(UNIQSTR_CMP): Replace by...
(uniqstr_cmp): this.
* src/uniqstr.c (uniqstr_cmp): New.
Produce well defined results.
* src/output.c: Use it.
---
 src/output.c  |  8 ++++----
 src/uniqstr.c | 13 ++++++++++++-
 src/uniqstr.h |  2 +-
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/output.c b/src/output.c
index c64c7aa..7e552dc 100644
--- a/src/output.c
+++ b/src/output.c
@@ -284,10 +284,10 @@ prepare_states (void)
 static int
 symbol_type_name_cmp (const symbol **lhs, const symbol **rhs)
 {
-  int res = UNIQSTR_CMP((*lhs)->type_name, (*rhs)->type_name);
-  if (res)
-    return res;
-  return (*lhs)->number - (*rhs)->number;
+  int res = uniqstr_cmp ((*lhs)->type_name, (*rhs)->type_name);
+  if (!res)
+    res = (*lhs)->number - (*rhs)->number;
+  return res;
 }
 
 
diff --git a/src/uniqstr.c b/src/uniqstr.c
index f295444..9917121 100644
--- a/src/uniqstr.c
+++ b/src/uniqstr.c
@@ -103,7 +103,17 @@ uniqstr_print_processor (void *ustr, void *null 
ATTRIBUTE_UNUSED)
   return uniqstr_print (ustr);
 }
 
-
+
+int
+uniqstr_cmp(uniqstr l, uniqstr r)
+{
+  return (l == r ? 0
+          : !l ? -1
+          : !r ? +1
+          : strcmp (l, r));
+}
+
+
 /*-----------------------.
 | A uniqstr hash table.  |
 `-----------------------*/
@@ -120,6 +130,7 @@ hash_uniqstr (void const *m, size_t tablesize)
   return hash_string (m, tablesize);
 }
 
+
 /*----------------------------.
 | Create the uniqstrs table.  |
 `----------------------------*/
diff --git a/src/uniqstr.h b/src/uniqstr.h
index ba27322..9990446 100644
--- a/src/uniqstr.h
+++ b/src/uniqstr.h
@@ -40,7 +40,7 @@ uniqstr uniqstr_vsprintf (char const *format, ...)
 
 /* Compare two uniqstr a la strcmp: negative for <, nul for =, and
    positive for >.  Undefined order, relies on addresses.  */
-# define UNIQSTR_CMP(USTR1, USTR2) ((USTR1) - (USTR2))
+int uniqstr_cmp(uniqstr u1, uniqstr u2);
 
 /* Die if STR is not a uniqstr.  */
 void uniqstr_assert (char const *str);
-- 
1.8.0.2