1 files changed, 124 insertions, 0 deletions

diff --git a/fs/ntfs/collate.c b/fs/ntfs/collate.c
new file mode 100644
index 000000000000..4a28ab3898ef
--- /dev/null
+++ b/fs/ntfs/collate.c
@@ -0,0 +1,124 @@
+/*
+ * collate.c - NTFS kernel collation handling.  Part of the Linux-NTFS project.
+ *
+ * Copyright (c) 2004 Anton Altaparmakov
+ *
+ * This program/include file 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program/include file 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 (in the main directory of the Linux-NTFS
+ * distribution in the file COPYING); if not, write to the Free Software
+ * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "collate.h"
+#include "debug.h"
+#include "ntfs.h"
+
+static int ntfs_collate_binary(ntfs_volume *vol,
+                const void *data1, const int data1_len,
+                const void *data2, const int data2_len)
+{
+        int rc;
+
+        ntfs_debug("Entering.");
+        rc = memcmp(data1, data2, min(data1_len, data2_len));
+        if (!rc && (data1_len != data2_len)) {
+                if (data1_len < data2_len)
+                        rc = -1;
+                else
+                        rc = 1;
+        }
+        ntfs_debug("Done, returning %i", rc);
+        return rc;
+}
+
+static int ntfs_collate_ntofs_ulong(ntfs_volume *vol,
+                const void *data1, const int data1_len,
+                const void *data2, const int data2_len)
+{
+        int rc;
+        u32 d1, d2;
+
+        ntfs_debug("Entering.");
+        // FIXME:  We don't really want to bug here.
+        BUG_ON(data1_len != data2_len);
+        BUG_ON(data1_len != 4);
+        d1 = le32_to_cpup(data1);
+        d2 = le32_to_cpup(data2);
+        if (d1 < d2)
+                rc = -1;
+        else {
+                if (d1 == d2)
+                        rc = 0;
+                else
+                        rc = 1;
+        }
+        ntfs_debug("Done, returning %i", rc);
+        return rc;
+}
+
+typedef int (*ntfs_collate_func_t)(ntfs_volume *, const void *, const int,
+                const void *, const int);
+
+static ntfs_collate_func_t ntfs_do_collate0x0[3] = {
+        ntfs_collate_binary,
+        NULL/*ntfs_collate_file_name*/,
+        NULL/*ntfs_collate_unicode_string*/,
+};
+
+static ntfs_collate_func_t ntfs_do_collate0x1[4] = {
+        ntfs_collate_ntofs_ulong,
+        NULL/*ntfs_collate_ntofs_sid*/,
+        NULL/*ntfs_collate_ntofs_security_hash*/,
+        NULL/*ntfs_collate_ntofs_ulongs*/,
+};
+
+/**
+ * ntfs_collate - collate two data items using a specified collation rule
+ * @vol:        ntfs volume to which the data items belong
+ * @cr:         collation rule to use when comparing the items
+ * @data1:      first data item to collate
+ * @data1_len:  length in bytes of @data1
+ * @data2:      second data item to collate
+ * @data2_len:  length in bytes of @data2
+ *
+ * Collate the two data items @data1 and @data2 using the collation rule @cr
+ * and return -1, 0, ir 1 if @data1 is found, respectively, to collate before,
+ * to match, or to collate after @data2.
+ *
+ * For speed we use the collation rule @cr as an index into two tables of
+ * function pointers to call the appropriate collation function.
+ */
+int ntfs_collate(ntfs_volume *vol, COLLATION_RULE cr,
+                const void *data1, const int data1_len,
+                const void *data2, const int data2_len) {
+        int i;
+
+        ntfs_debug("Entering.");
+        /*
+         * FIXME:  At the moment we only support COLLATION_BINARY and
+         * COLLATION_NTOFS_ULONG, so we BUG() for everything else for now.
+         */
+        BUG_ON(cr != COLLATION_BINARY && cr != COLLATION_NTOFS_ULONG);
+        i = le32_to_cpu(cr);
+        BUG_ON(i < 0);
+        if (i <= 0x02)
+                return ntfs_do_collate0x0[i](vol, data1, data1_len,
+                                data2, data2_len);
+        BUG_ON(i < 0x10);
+        i -= 0x10;
+        if (likely(i <= 3))
+                return ntfs_do_collate0x1[i](vol, data1, data1_len,
+                                data2, data2_len);
+        BUG();
+        return 0;
+}