include/qemu/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
  16 #include "qemu/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_set_atomic(dst, pos, nbits)   Set specified bit area with atomic ops
  39  * bitmap_clear(dst, pos, nbits)                Clear specified bit area
  40  * bitmap_test_and_clear_atomic(dst, pos, nbits)    Test and clear area
  41  * bitmap_find_next_zero_area(buf, len, pos, n, mask)   Find bit free area
  42  */
  43
  44 /*
  45  * Also the following operations apply to bitmaps.
  46  *
  47  * set_bit(bit, addr)                   *addr |= bit
  48  * clear_bit(bit, addr)                 *addr &= ~bit
  49  * change_bit(bit, addr)                *addr ^= bit
  50  * test_bit(bit, addr)                  Is bit set in *addr?
  51  * test_and_set_bit(bit, addr)          Set bit and return old value
  52  * test_and_clear_bit(bit, addr)        Clear bit and return old value
  53  * test_and_change_bit(bit, addr)       Change bit and return old value
  54  * find_first_zero_bit(addr, nbits)     Position first zero bit in *addr
  55  * find_first_bit(addr, nbits)          Position first set bit in *addr
  56  * find_next_zero_bit(addr, nbits, bit) Position next zero bit in *addr >= bit
  57  * find_next_bit(addr, nbits, bit)      Position next set bit in *addr >= bit
  58  */
  59
  60 #define BITMAP_LAST_WORD_MASK(nbits)                                    \
  61     (                                                                   \
  62         ((nbits) % BITS_PER_LONG) ?                                     \
  63         (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL                       \
  64         )
  65
  66 #define DECLARE_BITMAP(name,bits)                  \
  67         unsigned long name[BITS_TO_LONGS(bits)]
  68
  69 #define small_nbits(nbits)                      \
  70         ((nbits) <= BITS_PER_LONG)
  71
  72 int slow_bitmap_empty(const unsigned long *bitmap, long bits);
  73 int slow_bitmap_full(const unsigned long *bitmap, long bits);
  74 int slow_bitmap_equal(const unsigned long *bitmap1,
  75                       const unsigned long *bitmap2, long bits);
  76 void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
  77                             long bits);
  78 void slow_bitmap_shift_right(unsigned long *dst,
  79                              const unsigned long *src, int shift, long bits);
  80 void slow_bitmap_shift_left(unsigned long *dst,
  81                             const unsigned long *src, int shift, long bits);
  82 int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
  83                     const unsigned long *bitmap2, long bits);
  84 void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
  85                     const unsigned long *bitmap2, long bits);
  86 void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
  87                      const unsigned long *bitmap2, long bits);
  88 int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
  89                        const unsigned long *bitmap2, long bits);
  90 int slow_bitmap_intersects(const unsigned long *bitmap1,
  91                            const unsigned long *bitmap2, long bits);
  92
  93 static inline unsigned long *bitmap_try_new(long nbits)
  94 {
  95     long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
  96     return g_try_malloc0(len);
  97 }
  98
  99 static inline unsigned long *bitmap_new(long nbits)
 100 {
 101     unsigned long *ptr = bitmap_try_new(nbits);
 102     if (ptr == NULL) {
 103         abort();
 104     }
 105     return ptr;
 106 }
 107
 108 static inline void bitmap_zero(unsigned long *dst, long nbits)
 109 {
 110     if (small_nbits(nbits)) {
 111         *dst = 0UL;
 112     } else {
 113         long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 114         memset(dst, 0, len);
 115     }
 116 }
 117
 118 static inline void bitmap_fill(unsigned long *dst, long nbits)
 119 {
 120     size_t nlongs = BITS_TO_LONGS(nbits);
 121     if (!small_nbits(nbits)) {
 122         long len = (nlongs - 1) * sizeof(unsigned long);
 123         memset(dst, 0xff,  len);
 124     }
 125     dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
 126 }
 127
 128 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
 129                                long nbits)
 130 {
 131     if (small_nbits(nbits)) {
 132         *dst = *src;
 133     } else {
 134         long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 135         memcpy(dst, src, len);
 136     }
 137 }
 138
 139 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
 140                              const unsigned long *src2, long nbits)
 141 {
 142     if (small_nbits(nbits)) {
 143         return (*dst = *src1 & *src2) != 0;
 144     }
 145     return slow_bitmap_and(dst, src1, src2, nbits);
 146 }
 147
 148 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
 149                              const unsigned long *src2, long nbits)
 150 {
 151     if (small_nbits(nbits)) {
 152         *dst = *src1 | *src2;
 153     } else {
 154         slow_bitmap_or(dst, src1, src2, nbits);
 155     }
 156 }
 157
 158 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
 159                               const unsigned long *src2, long nbits)
 160 {
 161     if (small_nbits(nbits)) {
 162         *dst = *src1 ^ *src2;
 163     } else {
 164         slow_bitmap_xor(dst, src1, src2, nbits);
 165     }
 166 }
 167
 168 static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
 169                                 const unsigned long *src2, long nbits)
 170 {
 171     if (small_nbits(nbits)) {
 172         return (*dst = *src1 & ~(*src2)) != 0;
 173     }
 174     return slow_bitmap_andnot(dst, src1, src2, nbits);
 175 }
 176
 177 static inline void bitmap_complement(unsigned long *dst,
 178                                      const unsigned long *src,
 179                                      long nbits)
 180 {
 181     if (small_nbits(nbits)) {
 182         *dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
 183     } else {
 184         slow_bitmap_complement(dst, src, nbits);
 185     }
 186 }
 187
 188 static inline int bitmap_equal(const unsigned long *src1,
 189                                const unsigned long *src2, long nbits)
 190 {
 191     if (small_nbits(nbits)) {
 192         return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
 193     } else {
 194         return slow_bitmap_equal(src1, src2, nbits);
 195     }
 196 }
 197
 198 static inline int bitmap_empty(const unsigned long *src, long nbits)
 199 {
 200     if (small_nbits(nbits)) {
 201         return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
 202     } else {
 203         return slow_bitmap_empty(src, nbits);
 204     }
 205 }
 206
 207 static inline int bitmap_full(const unsigned long *src, long nbits)
 208 {
 209     if (small_nbits(nbits)) {
 210         return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
 211     } else {
 212         return slow_bitmap_full(src, nbits);
 213     }
 214 }
 215
 216 static inline int bitmap_intersects(const unsigned long *src1,
 217                                     const unsigned long *src2, long nbits)
 218 {
 219     if (small_nbits(nbits)) {
 220         return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 221     } else {
 222         return slow_bitmap_intersects(src1, src2, nbits);
 223     }
 224 }
 225
 226 void bitmap_set(unsigned long *map, long i, long len);
 227 void bitmap_set_atomic(unsigned long *map, long i, long len);
 228 void bitmap_clear(unsigned long *map, long start, long nr);
 229 bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr);
 230 unsigned long bitmap_find_next_zero_area(unsigned long *map,
 231                                          unsigned long size,
 232                                          unsigned long start,
 233                                          unsigned long nr,
 234                                          unsigned long align_mask);
 235
 236 static inline unsigned long *bitmap_zero_extend(unsigned long *old,
 237                                                 long old_nbits, long new_nbits)
 238 {
 239     long new_len = BITS_TO_LONGS(new_nbits) * sizeof(unsigned long);
 240     unsigned long *new = g_realloc(old, new_len);
 241     bitmap_clear(new, old_nbits, new_nbits - old_nbits);
 242     return new;
 243 }
 244
 245 #endif /* BITMAP_H */