libext2fs: find/alloc a range of empty blocks

[tools/e2fsprogs.git] / lib / ext2fs / bitops.c

diff --git a/lib/ext2fs/bitops.c b/lib/ext2fs/bitops.c
index 485e997..8e4c05c 100644 (file)
--- a/lib/ext2fs/bitops.c
+++ b/lib/ext2fs/bitops.c
@@ -5,11 +5,12 @@
  * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
  *
  * %Begin-Header%
- * This file may be redistributed under the terms of the GNU Public
- * License.
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
  * %End-Header%
  */
 
+#include "config.h"
 #include <stdio.h>
 #if HAVE_SYS_TYPES_H
 #include <sys/types.h>
@@ -76,3 +77,82 @@ void ext2fs_warn_bitmap(errcode_t errcode, unsigned long arg,
                com_err(0, errcode, "#%lu", arg);
 #endif
 }
+
+/*
+ * C-only 64 bit ops.
+ */
+
+int ext2fs_set_bit64(__u64 nr, void * addr)
+{
+       int             mask, retval;
+       unsigned char   *ADDR = (unsigned char *) addr;
+
+       ADDR += nr >> 3;
+       mask = 1 << (nr & 0x07);
+       retval = mask & *ADDR;
+       *ADDR |= mask;
+       return retval;
+}
+
+int ext2fs_clear_bit64(__u64 nr, void * addr)
+{
+       int             mask, retval;
+       unsigned char   *ADDR = (unsigned char *) addr;
+
+       ADDR += nr >> 3;
+       mask = 1 << (nr & 0x07);
+       retval = mask & *ADDR;
+       *ADDR &= ~mask;
+       return retval;
+}
+
+int ext2fs_test_bit64(__u64 nr, const void * addr)
+{
+       int                     mask;
+       const unsigned char     *ADDR = (const unsigned char *) addr;
+
+       ADDR += nr >> 3;
+       mask = 1 << (nr & 0x07);
+       return (mask & *ADDR);
+}
+
+static unsigned int popcount8(unsigned int w)
+{
+       unsigned int res = w - ((w >> 1) & 0x55);
+       res = (res & 0x33) + ((res >> 2) & 0x33);
+       return (res + (res >> 4)) & 0x0F;
+}
+
+static unsigned int popcount32(unsigned int w)
+{
+       unsigned int res = w - ((w >> 1) & 0x55555555);
+       res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
+       res = (res + (res >> 4)) & 0x0F0F0F0F;
+       res = res + (res >> 8);
+       return (res + (res >> 16)) & 0x000000FF;
+}
+
+unsigned int ext2fs_bitcount(const void *addr, unsigned int nbytes)
+{
+       const unsigned char *cp = addr;
+       const __u32 *p;
+       unsigned int res = 0;
+
+       while (((((unsigned long) cp) & 3) != 0) && (nbytes > 0)) {
+               res += popcount8(*cp++);
+               nbytes--;
+       }
+       p = (const __u32 *) cp;
+
+       while (nbytes > 4) {
+               res += popcount32(*p++);
+               nbytes -= 4;
+       }
+       cp = (const unsigned char *) p;
+
+       while (nbytes > 0) {
+               res += popcount8(*cp++);
+               nbytes--;
+       }
+       return res;
+}