bitmap.h

   1 /*
   2  * Bitmap Module
   3  *
   4  * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
   5  *
   6  * Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h
   7  *
   8  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
   9  * See the COPYING.LIB file in the top-level directory.
  10  */
  11
  12 #ifndef BITMAP_H
  13 #define BITMAP_H
  14
  15 #include "qemu-common.h"
  16 #include "bitops.h"
  17
  18 /*
  19  * The available bitmap operations and their rough meaning in the
  20  * case that the bitmap is a single unsigned long are thus:
  21  *
  22  * Note that nbits should be always a compile time evaluable constant.
  23  * Otherwise many inlines will generate horrible code.
  24  *
  25  * bitmap_zero(dst, nbits)                      *dst = 0UL
  26  * bitmap_fill(dst, nbits)                      *dst = ~0UL
  27  * bitmap_copy(dst, src, nbits)                 *dst = *src
  28  * bitmap_and(dst, src1, src2, nbits)           *dst = *src1 & *src2
  29  * bitmap_or(dst, src1, src2, nbits)            *dst = *src1 | *src2
  30  * bitmap_xor(dst, src1, src2, nbits)           *dst = *src1 ^ *src2
  31  * bitmap_andnot(dst, src1, src2, nbits)        *dst = *src1 & ~(*src2)
  32  * bitmap_complement(dst, src, nbits)           *dst = ~(*src)
  33  * bitmap_equal(src1, src2, nbits)              Are *src1 and *src2 equal?
  34  * bitmap_intersects(src1, src2, nbits)         Do *src1 and *src2 overlap?
  35  * bitmap_empty(src, nbits)                     Are all bits zero in *src?
  36  * bitmap_full(src, nbits)                      Are all bits set in *src?
  37  * bitmap_set(dst, pos, nbits)                  Set specified bit area
  38  * bitmap_clear(dst, pos, nbits)                Clear specified bit area
  39  * bitmap_find_next_zero_area(buf, len, pos, n, mask)   Find bit free area
  40  */
  41
  42 /*
  43  * Also the following operations apply to bitmaps.
  44  *
  45  * set_bit(bit, addr)                   *addr |= bit
  46  * clear_bit(bit, addr)                 *addr &= ~bit
  47  * change_bit(bit, addr)                *addr ^= bit
  48  * test_bit(bit, addr)                  Is bit set in *addr?
  49  * test_and_set_bit(bit, addr)          Set bit and return old value
  50  * test_and_clear_bit(bit, addr)        Clear bit and return old value
  51  * test_and_change_bit(bit, addr)       Change bit and return old value
  52  * find_first_zero_bit(addr, nbits)     Position first zero bit in *addr
  53  * find_first_bit(addr, nbits)          Position first set bit in *addr
  54  * find_next_zero_bit(addr, nbits, bit) Position next zero bit in *addr >= bit
  55  * find_next_bit(addr, nbits, bit)      Position next set bit in *addr >= bit
  56  */
  57
  58 #define BITMAP_LAST_WORD_MASK(nbits)                                    \
  59     (                                                                   \
  60         ((nbits) % BITS_PER_LONG) ?                                     \
  61         (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL                       \
  62         )
  63
  64 #define DECLARE_BITMAP(name,bits)                  \
  65         unsigned long name[BITS_TO_LONGS(bits)]
  66
  67 #define small_nbits(nbits)                      \
  68         ((nbits) <= BITS_PER_LONG)
  69
  70 int slow_bitmap_empty(const unsigned long *bitmap, int bits);
  71 int slow_bitmap_full(const unsigned long *bitmap, int bits);
  72 int slow_bitmap_equal(const unsigned long *bitmap1,
  73                    const unsigned long *bitmap2, int bits);
  74 void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
  75                          int bits);
  76 void slow_bitmap_shift_right(unsigned long *dst,
  77                           const unsigned long *src, int shift, int bits);
  78 void slow_bitmap_shift_left(unsigned long *dst,
  79                          const unsigned long *src, int shift, int bits);
  80 int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
  81                  const unsigned long *bitmap2, int bits);
  82 void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
  83                  const unsigned long *bitmap2, int bits);
  84 void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
  85                   const unsigned long *bitmap2, int bits);
  86 int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
  87                     const unsigned long *bitmap2, int bits);
  88 int slow_bitmap_intersects(const unsigned long *bitmap1,
  89                         const unsigned long *bitmap2, int bits);
  90
  91 static inline unsigned long *bitmap_new(int nbits)
  92 {
  93     int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
  94     return qemu_mallocz(len);
  95 }
  96
  97 static inline void bitmap_zero(unsigned long *dst, int nbits)
  98 {
  99     if (small_nbits(nbits)) {
 100         *dst = 0UL;
 101     } else {
 102         int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 103         memset(dst, 0, len);
 104     }
 105 }
 106
 107 static inline void bitmap_fill(unsigned long *dst, int nbits)
 108 {
 109     size_t nlongs = BITS_TO_LONGS(nbits);
 110     if (!small_nbits(nbits)) {
 111         int len = (nlongs - 1) * sizeof(unsigned long);
 112         memset(dst, 0xff,  len);
 113     }
 114     dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
 115 }
 116
 117 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
 118                                int nbits)
 119 {
 120     if (small_nbits(nbits)) {
 121         *dst = *src;
 122     } else {
 123         int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 124         memcpy(dst, src, len);
 125     }
 126 }
 127
 128 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
 129                              const unsigned long *src2, int nbits)
 130 {
 131     if (small_nbits(nbits)) {
 132         return (*dst = *src1 & *src2) != 0;
 133     }
 134     return slow_bitmap_and(dst, src1, src2, nbits);
 135 }
 136
 137 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
 138                         const unsigned long *src2, int nbits)
 139 {
 140     if (small_nbits(nbits)) {
 141         *dst = *src1 | *src2;
 142     } else {
 143         slow_bitmap_or(dst, src1, src2, nbits);
 144     }
 145 }
 146
 147 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
 148                         const unsigned long *src2, int nbits)
 149 {
 150     if (small_nbits(nbits)) {
 151         *dst = *src1 ^ *src2;
 152     } else {
 153         slow_bitmap_xor(dst, src1, src2, nbits);
 154     }
 155 }
 156
 157 static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
 158                         const unsigned long *src2, int nbits)
 159 {
 160     if (small_nbits(nbits)) {
 161         return (*dst = *src1 & ~(*src2)) != 0;
 162     }
 163     return slow_bitmap_andnot(dst, src1, src2, nbits);
 164 }
 165
 166 static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
 167                         int nbits)
 168 {
 169     if (small_nbits(nbits)) {
 170         *dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
 171     } else {
 172         slow_bitmap_complement(dst, src, nbits);
 173     }
 174 }
 175
 176 static inline int bitmap_equal(const unsigned long *src1,
 177                         const unsigned long *src2, int nbits)
 178 {
 179     if (small_nbits(nbits)) {
 180         return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
 181     } else {
 182         return slow_bitmap_equal(src1, src2, nbits);
 183     }
 184 }
 185
 186 static inline int bitmap_empty(const unsigned long *src, int nbits)
 187 {
 188     if (small_nbits(nbits)) {
 189         return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
 190     } else {
 191         return slow_bitmap_empty(src, nbits);
 192     }
 193 }
 194
 195 static inline int bitmap_full(const unsigned long *src, int nbits)
 196 {
 197     if (small_nbits(nbits)) {
 198         return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
 199     } else {
 200         return slow_bitmap_full(src, nbits);
 201     }
 202 }
 203
 204 static inline int bitmap_intersects(const unsigned long *src1,
 205                         const unsigned long *src2, int nbits)
 206 {
 207     if (small_nbits(nbits)) {
 208         return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 209     } else {
 210         return slow_bitmap_intersects(src1, src2, nbits);
 211     }
 212 }
 213
 214 void bitmap_set(unsigned long *map, int i, int len);
 215 void bitmap_clear(unsigned long *map, int start, int nr);
 216 unsigned long bitmap_find_next_zero_area(unsigned long *map,
 217                                          unsigned long size,
 218                                          unsigned long start,
 219                                          unsigned int nr,
 220                                          unsigned long align_mask);
 221
 222 #endif /* BITMAP_H */