1 files changed, 74 insertions, 0 deletions
diff --git a/lib/file-set.c b/lib/file-set.c
new file mode 100644
index 0000000..3270551
--- /dev/null
+++ b/lib/file-set.c
@@ -0,0 +1,74 @@
+/* Specialized functions to manipulate a set of files.
+   Copyright (C) 2007, 2009-2022 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* written by Jim Meyering */
+
+#include <config.h>
+#include "file-set.h"
+
+#include "hash-triple.h"
+#include "xalloc.h"
+
+/* Record file, FILE, and dev/ino from *STATS, in the hash table, HT.
+   If HT is NULL, return immediately.
+   If memory allocation fails, exit immediately.  */
+void
+record_file (Hash_table *ht, char const *file, struct stat const *stats)
+{
+  struct F_triple *ent;
+
+  if (ht == NULL)
+    return;
+
+  ent = xmalloc (sizeof *ent);
+  ent->name = xstrdup (file);
+  ent->st_ino = stats->st_ino;
+  ent->st_dev = stats->st_dev;
+
+  {
+    struct F_triple *ent_from_table = hash_insert (ht, ent);
+    if (ent_from_table == NULL)
+      {
+        /* Insertion failed due to lack of memory.  */
+        xalloc_die ();
+      }
+
+    if (ent_from_table != ent)
+      {
+        /* There was already a matching entry in the table, so ENT was
+           not inserted.  Free it.  */
+        triple_free (ent);
+      }
+  }
+}
+
+/* Return true if there is an entry in hash table, HT,
+   for the file described by FILE and STATS.  */
+bool
+seen_file (Hash_table const *ht, char const *file,
+           struct stat const *stats)
+{
+  struct F_triple new_ent;
+
+  if (ht == NULL)
+    return false;
+
+  new_ent.name = (char *) file;
+  new_ent.st_ino = stats->st_ino;
+  new_ent.st_dev = stats->st_dev;
+
+  return !!hash_lookup (ht, &new_ent);
+}