* XFS bit manipulation routines, used in non-realtime code.
*/
-#ifndef HAVE_ARCH_HIGHBIT
/*
- * Index of high bit number in byte, -1 for none set, 0..7 otherwise.
- */
-static 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.
+ * Return whether bitmap is empty.
+ * Size is number of words in the bitmap, which is padded to word boundary
+ * Returns 1 for empty, 0 for non-empty.
*/
int
-xfs_count_bits(uint *map, uint size, uint start_bit)
+xfs_bitmap_empty(uint *map, uint size)
{
- 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++;
- }
+ uint i;
+ uint ret = 0;
- /*
- * Count the bits in each byte until the end of the bitmap.
- */
- while (bytep < end_map) {
- bits += xfs_countbit[*bytep];
- bytep++;
+ for (i = 0; i < size; i++) {
+ ret |= map[i];
}
- return (bits);
+ return (ret == 0);
}
/*
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff