From b9fc790ddc0db2522b0d20d08fd2b8d40ef0fa4e Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@redhat.com>
Date: Mon, 7 Feb 2011 15:46:09 +0100
Subject: di-set: provide a lookup method

This is required for patch, and hence is about to move to gnulib.
* gl/lib/di-set.c (di_set_lookup): New function.
* gl/lib/di-set.h: Declare it.
* gl/tests/test-di-set.c (main): Exercise it.

The bug was introduced on 2004-12-04 via commit 7380cf79.
---
 gl/lib/di-set.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

(limited to 'gl/lib/di-set.c')

diff --git a/gl/lib/di-set.c b/gl/lib/di-set.c
index 05d24d609..5e839a311 100644
--- a/gl/lib/di-set.c
+++ b/gl/lib/di-set.c
@@ -235,3 +235,25 @@ di_set_insert (struct di_set *dis, dev_t dev, ino_t ino)
   /* Put I into the inode set.  */
   return hash_insert0 (ino_set, (void *) i, NULL);
 }
+
+/* Look up the DEV,INO pair in the set DIS.
+   If found, return 1; if not found, return 0.
+   Upon any failure return -1.  */
+int
+di_set_lookup (struct di_set *dis, dev_t dev, ino_t ino)
+{
+  hashint i;
+
+  /* Map the device number to a set of inodes.  */
+  struct hash_table *ino_set = map_device (dis, dev);
+  if (! ino_set)
+    return -1;
+
+  /* Map the inode number to a small representative I.  */
+  i = map_inode_number (dis, ino);
+  if (i == INO_MAP_INSERT_FAILURE)
+    return -1;
+
+  /* Perform the look-up.  */
+  return !!hash_lookup (ino_set, (void const *) i);
+}
-- 
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