1 files changed, 110 insertions, 0 deletions
diff --git a/fs/ntfs/collate.c b/fs/ntfs/collate.c
new file mode 100644
index 0000000000..3ab6ec96ab
--- /dev/null
+++ 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;
+}