1 files changed, 312 insertions, 0 deletions

diff --git a/fs/xfs/xfs_bit.c b/fs/xfs/xfs_bit.c
new file mode 100644
index 000000000000..a20a6c3dc13e
--- /dev/null
+++ b/fs/xfs/xfs_bit.c
@@ -0,0 +1,312 @@
+/*
+ * Copyright (c) 2000-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like.  Any license provided herein, whether implied or
+ * otherwise, applies only to this software file.  Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA  94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
+ */
+
+/*
+ * XFS bit manipulation routines, used in non-realtime code.
+ */
+
+#include "xfs.h"
+#include "xfs_bit.h"
+#include "xfs_log.h"
+#include "xfs_trans.h"
+#include "xfs_buf_item.h"
+
+
+#ifndef HAVE_ARCH_HIGHBIT
+/*
+ * Index of high bit number in byte, -1 for none set, 0..7 otherwise.
+ */
+const char xfs_highbit[256] = {
+       -1, 0, 1, 1, 2, 2, 2, 2,                 /* 00 .. 07 */
+        3, 3, 3, 3, 3, 3, 3, 3,                 /* 08 .. 0f */
+        4, 4, 4, 4, 4, 4, 4, 4,                 /* 10 .. 17 */
+        4, 4, 4, 4, 4, 4, 4, 4,                 /* 18 .. 1f */
+        5, 5, 5, 5, 5, 5, 5, 5,                 /* 20 .. 27 */
+        5, 5, 5, 5, 5, 5, 5, 5,                 /* 28 .. 2f */
+        5, 5, 5, 5, 5, 5, 5, 5,                 /* 30 .. 37 */
+        5, 5, 5, 5, 5, 5, 5, 5,                 /* 38 .. 3f */
+        6, 6, 6, 6, 6, 6, 6, 6,                 /* 40 .. 47 */
+        6, 6, 6, 6, 6, 6, 6, 6,                 /* 48 .. 4f */
+        6, 6, 6, 6, 6, 6, 6, 6,                 /* 50 .. 57 */
+        6, 6, 6, 6, 6, 6, 6, 6,                 /* 58 .. 5f */
+        6, 6, 6, 6, 6, 6, 6, 6,                 /* 60 .. 67 */
+        6, 6, 6, 6, 6, 6, 6, 6,                 /* 68 .. 6f */
+        6, 6, 6, 6, 6, 6, 6, 6,                 /* 70 .. 77 */
+        6, 6, 6, 6, 6, 6, 6, 6,                 /* 78 .. 7f */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* 80 .. 87 */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* 88 .. 8f */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* 90 .. 97 */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* 98 .. 9f */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* a0 .. a7 */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* a8 .. af */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* b0 .. b7 */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* b8 .. bf */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* c0 .. c7 */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* c8 .. cf */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* d0 .. d7 */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* d8 .. df */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* e0 .. e7 */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* e8 .. ef */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* f0 .. f7 */
+        7, 7, 7, 7, 7, 7, 7, 7,                 /* f8 .. ff */
+};
+#endif
+
+/*
+ * Count of bits set in byte, 0..8.
+ */
+static const char xfs_countbit[256] = {
+        0, 1, 1, 2, 1, 2, 2, 3,                 /* 00 .. 07 */
+        1, 2, 2, 3, 2, 3, 3, 4,                 /* 08 .. 0f */
+        1, 2, 2, 3, 2, 3, 3, 4,                 /* 10 .. 17 */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* 18 .. 1f */
+        1, 2, 2, 3, 2, 3, 3, 4,                 /* 20 .. 27 */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* 28 .. 2f */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* 30 .. 37 */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* 38 .. 3f */
+        1, 2, 2, 3, 2, 3, 3, 4,                 /* 40 .. 47 */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* 48 .. 4f */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* 50 .. 57 */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* 58 .. 5f */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* 60 .. 67 */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* 68 .. 6f */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* 70 .. 77 */
+        4, 5, 5, 6, 5, 6, 6, 7,                 /* 78 .. 7f */
+        1, 2, 2, 3, 2, 3, 3, 4,                 /* 80 .. 87 */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* 88 .. 8f */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* 90 .. 97 */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* 98 .. 9f */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* a0 .. a7 */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* a8 .. af */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* b0 .. b7 */
+        4, 5, 5, 6, 5, 6, 6, 7,                 /* b8 .. bf */
+        2, 3, 3, 4, 3, 4, 4, 5,                 /* c0 .. c7 */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* c8 .. cf */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* d0 .. d7 */
+        4, 5, 5, 6, 5, 6, 6, 7,                 /* d8 .. df */
+        3, 4, 4, 5, 4, 5, 5, 6,                 /* e0 .. e7 */
+        4, 5, 5, 6, 5, 6, 6, 7,                 /* e8 .. ef */
+        4, 5, 5, 6, 5, 6, 6, 7,                 /* f0 .. f7 */
+        5, 6, 6, 7, 6, 7, 7, 8,                 /* f8 .. ff */
+};
+
+/*
+ * xfs_highbit32: get high bit set out of 32-bit argument, -1 if none set.
+ */
+inline int
+xfs_highbit32(
+        __uint32_t      v)
+{
+#ifdef HAVE_ARCH_HIGHBIT
+        return highbit32(v);
+#else
+        int             i;
+
+        if (v & 0xffff0000)
+                if (v & 0xff000000)
+                        i = 24;
+                else
+                        i = 16;
+        else if (v & 0x0000ffff)
+                if (v & 0x0000ff00)
+                        i = 8;
+                else
+                        i = 0;
+        else
+                return -1;
+        return i + xfs_highbit[(v >> i) & 0xff];
+#endif
+}
+
+/*
+ * xfs_lowbit64: get low bit set out of 64-bit argument, -1 if none set.
+ */
+int
+xfs_lowbit64(
+        __uint64_t      v)
+{
+        __uint32_t      w = (__uint32_t)v;
+        int             n = 0;
+
+        if (w) {        /* lower bits */
+                n = ffs(w);
+        } else {        /* upper bits */
+                w = (__uint32_t)(v >> 32);
+                if (w && (n = ffs(w)))
+                        n += 32;
+        }
+        return n - 1;
+}
+
+/*
+ * xfs_highbit64: get high bit set out of 64-bit argument, -1 if none set.
+ */
+int
+xfs_highbit64(
+        __uint64_t      v)
+{
+        __uint32_t      h = (__uint32_t)(v >> 32);
+
+        if (h)
+                return xfs_highbit32(h) + 32;
+        return xfs_highbit32((__uint32_t)v);
+}
+
+
+/*
+ * Count the number of bits set in the bitmap starting with bit
+ * start_bit.  Size is the size of the bitmap in words.
+ *
+ * Do the counting by mapping a byte value to the number of set
+ * bits for that value using the xfs_countbit array, i.e.
+ * xfs_countbit[0] == 0, xfs_countbit[1] == 1, xfs_countbit[2] == 1,
+ * xfs_countbit[3] == 2, etc.
+ */
+int
+xfs_count_bits(uint *map, uint size, uint start_bit)
+{
+        register int    bits;
+        register unsigned char  *bytep;
+        register unsigned char  *end_map;
+        int             byte_bit;
+
+        bits = 0;
+        end_map = (char*)(map + size);
+        bytep = (char*)(map + (start_bit & ~0x7));
+        byte_bit = start_bit & 0x7;
+
+        /*
+         * If the caller fell off the end of the map, return 0.
+         */
+        if (bytep >= end_map) {
+                return (0);
+        }
+
+        /*
+         * If start_bit is not byte aligned, then process the
+         * first byte separately.
+         */
+        if (byte_bit != 0) {
+                /*
+                 * Shift off the bits we don't want to look at,
+                 * before indexing into xfs_countbit.
+                 */
+                bits += xfs_countbit[(*bytep >> byte_bit)];
+                bytep++;
+        }
+
+        /*
+         * Count the bits in each byte until the end of the bitmap.
+         */
+        while (bytep < end_map) {
+                bits += xfs_countbit[*bytep];
+                bytep++;
+        }
+
+        return (bits);
+}
+
+/*
+ * Count the number of contiguous bits set in the bitmap starting with bit
+ * start_bit.  Size is the size of the bitmap in words.
+ */
+int
+xfs_contig_bits(uint *map, uint size, uint start_bit)
+{
+        uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT);
+        uint result = 0;
+        uint tmp;
+
+        size <<= BIT_TO_WORD_SHIFT;
+
+        ASSERT(start_bit < size);
+        size -= start_bit & ~(NBWORD - 1);
+        start_bit &= (NBWORD - 1);
+        if (start_bit) {
+                tmp = *p++;
+                /* set to one first offset bits prior to start */
+                tmp |= (~0U >> (NBWORD-start_bit));
+                if (tmp != ~0U)
+                        goto found;
+                result += NBWORD;
+                size -= NBWORD;
+        }
+        while (size) {
+                if ((tmp = *p++) != ~0U)
+                        goto found;
+                result += NBWORD;
+                size -= NBWORD;
+        }
+        return result - start_bit;
+found:
+        return result + ffz(tmp) - start_bit;
+}
+
+/*
+ * This takes the bit number to start looking from and
+ * returns the next set bit from there.  It returns -1
+ * if there are no more bits set or the start bit is
+ * beyond the end of the bitmap.
+ *
+ * Size is the number of words, not bytes, in the bitmap.
+ */
+int xfs_next_bit(uint *map, uint size, uint start_bit)
+{
+        uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT);
+        uint result = start_bit & ~(NBWORD - 1);
+        uint tmp;
+
+        size <<= BIT_TO_WORD_SHIFT;
+
+        if (start_bit >= size)
+                return -1;
+        size -= result;
+        start_bit &= (NBWORD - 1);
+        if (start_bit) {
+                tmp = *p++;
+                /* set to zero first offset bits prior to start */
+                tmp &= (~0U << start_bit);
+                if (tmp != 0U)
+                        goto found;
+                result += NBWORD;
+                size -= NBWORD;
+        }
+        while (size) {
+                if ((tmp = *p++) != 0U)
+                        goto found;
+                result += NBWORD;
+                size -= NBWORD;
+        }
+        return -1;
+found:
+        return result + ffs(tmp) - 1;
+}