diff options
Diffstat (limited to 'lib/bitmap.c')
-rw-r--r-- | lib/bitmap.c | 68 |
1 files changed, 25 insertions, 43 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index 488e6c3e5acc..1c81413c51f8 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -333,20 +333,32 @@ bool __bitmap_subset(const unsigned long *bitmap1, } EXPORT_SYMBOL(__bitmap_subset); +#define BITMAP_WEIGHT(FETCH, bits) \ +({ \ + unsigned int __bits = (bits), idx, w = 0; \ + \ + for (idx = 0; idx < __bits / BITS_PER_LONG; idx++) \ + w += hweight_long(FETCH); \ + \ + if (__bits % BITS_PER_LONG) \ + w += hweight_long((FETCH) & BITMAP_LAST_WORD_MASK(__bits)); \ + \ + w; \ +}) + unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) { - unsigned int k, lim = bits/BITS_PER_LONG, w = 0; - - for (k = 0; k < lim; k++) - w += hweight_long(bitmap[k]); - - if (bits % BITS_PER_LONG) - w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); - - return w; + return BITMAP_WEIGHT(bitmap[idx], bits); } EXPORT_SYMBOL(__bitmap_weight); +unsigned int __bitmap_weight_and(const unsigned long *bitmap1, + const unsigned long *bitmap2, unsigned int bits) +{ + return BITMAP_WEIGHT(bitmap1[idx] & bitmap2[idx], bits); +} +EXPORT_SYMBOL(__bitmap_weight_and); + void __bitmap_set(unsigned long *map, unsigned int start, int len) { unsigned long *p = map + BIT_WORD(start); @@ -953,37 +965,7 @@ static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigne if (pos >= nbits || !test_bit(pos, buf)) return -1; - return __bitmap_weight(buf, pos); -} - -/** - * bitmap_ord_to_pos - find position of n-th set bit in bitmap - * @buf: pointer to bitmap - * @ord: ordinal bit position (n-th set bit, n >= 0) - * @nbits: number of valid bit positions in @buf - * - * Map the ordinal offset of bit @ord in @buf to its position in @buf. - * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord - * >= weight(buf), returns @nbits. - * - * If for example, just bits 4 through 7 are set in @buf, then @ord - * values 0 through 3 will get mapped to 4 through 7, respectively, - * and all other @ord values returns @nbits. When @ord value 3 - * gets mapped to (returns) @pos value 7 in this example, that means - * that the 3rd set bit (starting with 0th) is at position 7 in @buf. - * - * The bit positions 0 through @nbits-1 are valid positions in @buf. - */ -unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits) -{ - unsigned int pos; - - for (pos = find_first_bit(buf, nbits); - pos < nbits && ord; - pos = find_next_bit(buf, nbits, pos + 1)) - ord--; - - return pos; + return bitmap_weight(buf, pos); } /** @@ -1035,7 +1017,7 @@ void bitmap_remap(unsigned long *dst, const unsigned long *src, if (n < 0 || w == 0) set_bit(oldbit, dst); /* identity map */ else - set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst); + set_bit(find_nth_bit(new, nbits, n % w), dst); } } EXPORT_SYMBOL(bitmap_remap); @@ -1074,7 +1056,7 @@ int bitmap_bitremap(int oldbit, const unsigned long *old, if (n < 0 || w == 0) return oldbit; else - return bitmap_ord_to_pos(new, n % w, bits); + return find_nth_bit(new, bits, n % w); } EXPORT_SYMBOL(bitmap_bitremap); @@ -1198,7 +1180,7 @@ void bitmap_onto(unsigned long *dst, const unsigned long *orig, * The following code is a more efficient, but less * obvious, equivalent to the loop: * for (m = 0; m < bitmap_weight(relmap, bits); m++) { - * n = bitmap_ord_to_pos(orig, m, bits); + * n = find_nth_bit(orig, bits, m); * if (test_bit(m, orig)) * set_bit(n, dst); * } |