FreeBSD/Linux Kernel Cross Reference
sys/contrib/ck/include/ck_bitmap.h

     /*
      * Copyright 2012-2015 Samy Al Bahra.
      * Copyright 2012-2014 AppNexus, Inc.
      * Copyright 2014 Paul Khuong.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #ifndef CK_BITMAP_H
    #define CK_BITMAP_H
    
    #include <ck_cc.h>
    #include <ck_limits.h>
    #include <ck_pr.h>
    #include <ck_stdint.h>
    #include <ck_stdbool.h>
    #include <ck_stddef.h>
    #include <ck_stdbool.h>
    #include <ck_stddef.h>
    #include <ck_string.h>
    
    #if !defined(CK_F_PR_LOAD_UINT) || !defined(CK_F_PR_STORE_UINT) || \
        !defined(CK_F_PR_AND_UINT) || !defined(CK_F_PR_OR_UINT) || \
        !defined(CK_F_CC_CTZ)
    #error "ck_bitmap is not supported on your platform."
    #endif
    
    #define CK_BITMAP_BLOCK         (sizeof(unsigned int) * CHAR_BIT)
    #define CK_BITMAP_OFFSET(i)     ((i) % CK_BITMAP_BLOCK)
    #define CK_BITMAP_BIT(i)        (1U << CK_BITMAP_OFFSET(i))
    #define CK_BITMAP_PTR(x, i)     ((x) + ((i) / CK_BITMAP_BLOCK))
    #define CK_BITMAP_BLOCKS(n)     (((n) + CK_BITMAP_BLOCK - 1) / CK_BITMAP_BLOCK)
    
    #define CK_BITMAP_INSTANCE(n_entries)                                   \
            union {                                                         \
                    struct {                                                \
                            unsigned int n_bits;                            \
                            unsigned int map[CK_BITMAP_BLOCKS(n_entries)];  \
                    } content;                                              \
                    struct ck_bitmap bitmap;                                \
            }
    
    #define CK_BITMAP_ITERATOR_INIT(a, b) \
            ck_bitmap_iterator_init((a), &(b)->bitmap)
    
    #define CK_BITMAP_INIT(a, b, c) \
            ck_bitmap_init(&(a)->bitmap, (b), (c))
    
    #define CK_BITMAP_NEXT(a, b, c) \
            ck_bitmap_next(&(a)->bitmap, (b), (c))
    
    #define CK_BITMAP_SET(a, b) \
            ck_bitmap_set(&(a)->bitmap, (b))
    
    #define CK_BITMAP_BTS(a, b) \
            ck_bitmap_bts(&(a)->bitmap, (b))
    
    #define CK_BITMAP_RESET(a, b) \
            ck_bitmap_reset(&(a)->bitmap, (b))
    
    #define CK_BITMAP_TEST(a, b) \
            ck_bitmap_test(&(a)->bitmap, (b))
    
    #define CK_BITMAP_UNION(a, b) \
            ck_bitmap_union(&(a)->bitmap, &(b)->bitmap)
    
    #define CK_BITMAP_INTERSECTION(a, b) \
            ck_bitmap_intersection(&(a)->bitmap, &(b)->bitmap)
    
    #define CK_BITMAP_INTERSECTION_NEGATE(a, b) \
            ck_bitmap_intersection_negate(&(a)->bitmap, &(b)->bitmap)
    
    #define CK_BITMAP_CLEAR(a) \
            ck_bitmap_clear(&(a)->bitmap)
    
    #define CK_BITMAP_EMPTY(a, b) \
            ck_bitmap_empty(&(a)->bitmap, b)
    
    #define CK_BITMAP_FULL(a, b) \
           ck_bitmap_full(&(a)->bitmap, b)
   
   #define CK_BITMAP_COUNT(a, b) \
           ck_bitmap_count(&(a)->bitmap, b)
   
   #define CK_BITMAP_COUNT_INTERSECT(a, b, c) \
           ck_bitmap_count_intersect(&(a)->bitmap, b, c)
   
   #define CK_BITMAP_BITS(a) \
           ck_bitmap_bits(&(a)->bitmap)
   
   #define CK_BITMAP_BUFFER(a) \
           ck_bitmap_buffer(&(a)->bitmap)
   
   #define CK_BITMAP(a) \
           (&(a)->bitmap)
   
   struct ck_bitmap {
           unsigned int n_bits;
           unsigned int map[];
   };
   typedef struct ck_bitmap ck_bitmap_t;
   
   struct ck_bitmap_iterator {
           unsigned int cache;
           unsigned int n_block;
           unsigned int n_limit;
   };
   typedef struct ck_bitmap_iterator ck_bitmap_iterator_t;
   
   CK_CC_INLINE static unsigned int
   ck_bitmap_base(unsigned int n_bits)
   {
   
           return CK_BITMAP_BLOCKS(n_bits) * sizeof(unsigned int);
   }
   
   /*
    * Returns the required number of bytes for a ck_bitmap_t object supporting the
    * specified number of bits.
    */
   CK_CC_INLINE static unsigned int
   ck_bitmap_size(unsigned int n_bits)
   {
   
           return ck_bitmap_base(n_bits) + sizeof(struct ck_bitmap);
   }
   
   /*
    * Returns total number of bits in specified bitmap.
    */
   CK_CC_INLINE static unsigned int
   ck_bitmap_bits(const struct ck_bitmap *bitmap)
   {
   
           return bitmap->n_bits;
   }
   
   /*
    * Returns a pointer to the bit buffer associated
    * with the specified bitmap.
    */
   CK_CC_INLINE static void *
   ck_bitmap_buffer(struct ck_bitmap *bitmap)
   {
   
           return bitmap->map;
   }
   
   /*
    * Sets the bit at the offset specified in the second argument.
    */
   CK_CC_INLINE static void
   ck_bitmap_set(struct ck_bitmap *bitmap, unsigned int n)
   {
   
           ck_pr_or_uint(CK_BITMAP_PTR(bitmap->map, n), CK_BITMAP_BIT(n));
           return;
   }
   
   /*
    * Performs a test-and-set operation at the offset specified in the
    * second argument.
    * Returns true if the bit at the specified offset was already set,
    * false otherwise.
    */
   CK_CC_INLINE static bool
   ck_bitmap_bts(struct ck_bitmap *bitmap, unsigned int n)
   {
   
           return ck_pr_bts_uint(CK_BITMAP_PTR(bitmap->map, n),
               CK_BITMAP_OFFSET(n));
   }
   
   /*
    * Resets the bit at the offset specified in the second argument.
    */
   CK_CC_INLINE static void
   ck_bitmap_reset(struct ck_bitmap *bitmap, unsigned int n)
   {
   
           ck_pr_and_uint(CK_BITMAP_PTR(bitmap->map, n), ~CK_BITMAP_BIT(n));
           return;
   }
   
   /*
    * Determines whether the bit at offset specified in the
    * second argument is set.
    */
   CK_CC_INLINE static bool
   ck_bitmap_test(const struct ck_bitmap *bitmap, unsigned int n)
   {
           unsigned int block;
   
           block = ck_pr_load_uint(CK_BITMAP_PTR(bitmap->map, n));
           return block & CK_BITMAP_BIT(n);
   }
   
   /*
    * Combines bits from second bitmap into the first bitmap. This is not a
    * linearized operation with respect to the complete bitmap.
    */
   CK_CC_INLINE static void
   ck_bitmap_union(struct ck_bitmap *dst, const struct ck_bitmap *src)
   {
           unsigned int n;
           unsigned int n_buckets = dst->n_bits;
   
           if (src->n_bits < dst->n_bits)
                   n_buckets = src->n_bits;
   
           n_buckets = CK_BITMAP_BLOCKS(n_buckets);
           for (n = 0; n < n_buckets; n++) {
                   ck_pr_or_uint(&dst->map[n],
                       ck_pr_load_uint(&src->map[n]));
           }
   
           return;
   }
   
   /*
    * Intersects bits from second bitmap into the first bitmap. This is
    * not a linearized operation with respect to the complete bitmap.
    * Any trailing bit in dst is cleared.
    */
   CK_CC_INLINE static void
   ck_bitmap_intersection(struct ck_bitmap *dst, const struct ck_bitmap *src)
   {
           unsigned int n;
           unsigned int n_buckets = dst->n_bits;
           unsigned int n_intersect = n_buckets;
   
           if (src->n_bits < n_intersect)
                   n_intersect = src->n_bits;
   
           n_buckets = CK_BITMAP_BLOCKS(n_buckets);
           n_intersect = CK_BITMAP_BLOCKS(n_intersect);
           for (n = 0; n < n_intersect; n++) {
                   ck_pr_and_uint(&dst->map[n],
                       ck_pr_load_uint(&src->map[n]));
           }
   
           for (; n < n_buckets; n++)
                   ck_pr_store_uint(&dst->map[n], 0);
   
           return;
   }
   
   /*
    * Intersects the complement of bits from second bitmap into the first
    * bitmap. This is not a linearized operation with respect to the
    * complete bitmap.  Any trailing bit in dst is left as is.
    */
   CK_CC_INLINE static void
   ck_bitmap_intersection_negate(struct ck_bitmap *dst,
       const struct ck_bitmap *src)
   {
           unsigned int n;
           unsigned int n_intersect = dst->n_bits;
   
           if (src->n_bits < n_intersect)
                   n_intersect = src->n_bits;
   
           n_intersect = CK_BITMAP_BLOCKS(n_intersect);
           for (n = 0; n < n_intersect; n++) {
                   ck_pr_and_uint(&dst->map[n],
                       (~ck_pr_load_uint(&src->map[n])));
           }
   
           return;
   }
   
   /*
    * Resets all bits in the provided bitmap. This is not a linearized
    * operation in ck_bitmap.
    */
   CK_CC_INLINE static void
   ck_bitmap_clear(struct ck_bitmap *bitmap)
   {
           unsigned int i;
           unsigned int n_buckets = ck_bitmap_base(bitmap->n_bits) /
               sizeof(unsigned int);
   
           for (i = 0; i < n_buckets; i++)
                   ck_pr_store_uint(&bitmap->map[i], 0);
   
           return;
   }
   
   /*
    * Returns true if the first limit bits in bitmap are cleared.  If
    * limit is greater than the bitmap size, limit is truncated to that
    * size.
    */
   CK_CC_INLINE static bool
   ck_bitmap_empty(const ck_bitmap_t *bitmap, unsigned int limit)
   {
           unsigned int i, words, slop;
   
           if (limit > bitmap->n_bits)
                   limit = bitmap->n_bits;
   
           words = limit / CK_BITMAP_BLOCK;
           slop = limit % CK_BITMAP_BLOCK;
           for (i = 0; i < words; i++) {
                   if (ck_pr_load_uint(&bitmap->map[i]) != 0) {
                           return false;
                   }
           }
   
           if (slop > 0) {
                   unsigned int word;
   
                   word = ck_pr_load_uint(&bitmap->map[i]);
                   if ((word & ((1U << slop) - 1)) != 0)
                           return false;
           }
   
           return true;
   }
   
   /*
    * Returns true if the first limit bits in bitmap are set.  If limit
    * is greater than the bitmap size, limit is truncated to that size.
    */
   CK_CC_UNUSED static bool
   ck_bitmap_full(const ck_bitmap_t *bitmap, unsigned int limit)
   {
           unsigned int i, slop, words;
   
           if (limit > bitmap->n_bits) {
                   limit = bitmap->n_bits;
           }
   
           words = limit / CK_BITMAP_BLOCK;
           slop = limit % CK_BITMAP_BLOCK;
           for (i = 0; i < words; i++) {
                   if (ck_pr_load_uint(&bitmap->map[i]) != -1U)
                           return false;
           }
   
           if (slop > 0) {
                   unsigned int word;
   
                   word = ~ck_pr_load_uint(&bitmap->map[i]);
                   if ((word & ((1U << slop) - 1)) != 0)
                           return false;
           }
           return true;
   }
   
   /*
    * Returns the number of set bit in bitmap, upto (and excluding)
    * limit.  If limit is greater than the bitmap size, it is truncated
    * to that size.
    */
   CK_CC_INLINE static unsigned int
   ck_bitmap_count(const ck_bitmap_t *bitmap, unsigned int limit)
   {
           unsigned int count, i, slop, words;
   
           if (limit > bitmap->n_bits)
                   limit = bitmap->n_bits;
   
           words = limit / CK_BITMAP_BLOCK;
           slop = limit % CK_BITMAP_BLOCK;
           for (i = 0, count = 0; i < words; i++)
                   count += ck_cc_popcount(ck_pr_load_uint(&bitmap->map[i]));
   
           if (slop > 0) {
                   unsigned int word;
   
                   word = ck_pr_load_uint(&bitmap->map[i]);
                   count += ck_cc_popcount(word & ((1U << slop) - 1));
           }
           return count;
   }
   
   /*
    * Returns the number of set bit in the intersection of two bitmaps,
    * upto (and excluding) limit.  If limit is greater than either bitmap
    * size, it is truncated to the smallest.
    */
   CK_CC_INLINE static unsigned int
   ck_bitmap_count_intersect(const ck_bitmap_t *x, const ck_bitmap_t *y,
       unsigned int limit)
   {
           unsigned int count, i, slop, words;
   
           if (limit > x->n_bits)
                   limit = x->n_bits;
   
           if (limit > y->n_bits)
                   limit = y->n_bits;
   
           words = limit / CK_BITMAP_BLOCK;
           slop = limit % CK_BITMAP_BLOCK;
           for (i = 0, count = 0; i < words; i++) {
                   unsigned int xi, yi;
   
                   xi = ck_pr_load_uint(&x->map[i]);
                   yi = ck_pr_load_uint(&y->map[i]);
                   count += ck_cc_popcount(xi & yi);
           }
   
           if (slop > 0) {
                   unsigned int word, xi, yi;
   
                   xi = ck_pr_load_uint(&x->map[i]);
                   yi = ck_pr_load_uint(&y->map[i]);
                   word = xi & yi;
                   count += ck_cc_popcount(word & ((1U << slop) - 1));
           }
           return count;
   }
   
   /*
    * Initializes a ck_bitmap pointing to a region of memory with
    * ck_bitmap_size(n_bits) bytes. Third argument determines whether
    * default bit value is 1 (true) or 0 (false).
    */
   CK_CC_INLINE static void
   ck_bitmap_init(struct ck_bitmap *bitmap,
                  unsigned int n_bits,
                  bool set)
   {
           unsigned int base = ck_bitmap_base(n_bits);
   
           bitmap->n_bits = n_bits;
           memset(bitmap->map, -(int)set, base);
   
           if (set == true) {
                   unsigned int b = n_bits % CK_BITMAP_BLOCK;
   
                   if (b == 0)
                           return;
   
                   *CK_BITMAP_PTR(bitmap->map, n_bits - 1) &= (1U << b) - 1U;
           }
   
           return;
   }
   
   /*
    * Initialize iterator for use with provided bitmap.
    */
   CK_CC_INLINE static void
   ck_bitmap_iterator_init(struct ck_bitmap_iterator *i,
       const struct ck_bitmap *bitmap)
   {
   
           i->n_block = 0;
           i->n_limit = CK_BITMAP_BLOCKS(bitmap->n_bits);
           if (i->n_limit > 0) {
                   i->cache = ck_pr_load_uint(&bitmap->map[0]);
           } else {
                   i->cache = 0;
           }
           return;
   }
   
   /*
    * Iterate to next bit.
    */
   CK_CC_INLINE static bool
   ck_bitmap_next(const struct ck_bitmap *bitmap,
                  struct ck_bitmap_iterator *i,
                  unsigned int *bit)
   {
           unsigned int cache = i->cache;
           unsigned int n_block = i->n_block;
           unsigned int n_limit = i->n_limit;
   
           if (cache == 0) {
                   if (n_block >= n_limit)
                           return false;
   
                   for (n_block++; n_block < n_limit; n_block++) {
                           cache = ck_pr_load_uint(&bitmap->map[n_block]);
                           if (cache != 0)
                                   goto non_zero;
                   }
   
                   i->cache = 0;
                   i->n_block = n_block;
                   return false;
           }
   
   non_zero:
           *bit = CK_BITMAP_BLOCK * n_block + ck_cc_ctz(cache);
           i->cache = cache & (cache - 1);
           i->n_block = n_block;
           return true;
   }
   
   #endif /* CK_BITMAP_H */

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