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-rw-r--r--fs/ntfs/collate.c110
1 files changed, 110 insertions, 0 deletions
diff --git a/fs/ntfs/collate.c b/fs/ntfs/collate.c
new file mode 100644
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+++ b/fs/ntfs/collate.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * collate.c - NTFS kernel collation handling. Part of the Linux-NTFS project.
+ *
+ * Copyright (c) 2004 Anton Altaparmakov
+ */
+
+#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;
+}