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 #include <glib.h>
  16 #include <string.h>
  17 #include <stdlib.h>
  18
  19 #include "qemu/osdep.h"
  20 #include "qemu/bitops.h"
  21
  22 /*
  23  * The available bitmap operations and their rough meaning in the
  24  * case that the bitmap is a single unsigned long are thus:
  25  *
  26  * Note that nbits should be always a compile time evaluable constant.
  27  * Otherwise many inlines will generate horrible code.
  28  *
  29  * bitmap_zero(dst, nbits)                      *dst = 0UL
  30  * bitmap_fill(dst, nbits)                      *dst = ~0UL
  31  * bitmap_copy(dst, src, nbits)                 *dst = *src
  32  * bitmap_and(dst, src1, src2, nbits)           *dst = *src1 & *src2
  33  * bitmap_or(dst, src1, src2, nbits)            *dst = *src1 | *src2
  34  * bitmap_xor(dst, src1, src2, nbits)           *dst = *src1 ^ *src2
  35  * bitmap_andnot(dst, src1, src2, nbits)        *dst = *src1 & ~(*src2)
  36  * bitmap_complement(dst, src, nbits)           *dst = ~(*src)
  37  * bitmap_equal(src1, src2, nbits)              Are *src1 and *src2 equal?
  38  * bitmap_intersects(src1, src2, nbits)         Do *src1 and *src2 overlap?
  39  * bitmap_empty(src, nbits)                     Are all bits zero in *src?
  40  * bitmap_full(src, nbits)                      Are all bits set in *src?
  41  * bitmap_set(dst, pos, nbits)                  Set specified bit area
  42  * bitmap_clear(dst, pos, nbits)                Clear specified bit area
  43  * bitmap_find_next_zero_area(buf, len, pos, n, mask)   Find bit free area
  44  */
  45
  46 /*
  47  * Also the following operations apply to bitmaps.
  48  *
  49  * set_bit(bit, addr)                   *addr |= bit
  50  * clear_bit(bit, addr)                 *addr &= ~bit
  51  * change_bit(bit, addr)                *addr ^= bit
  52  * test_bit(bit, addr)                  Is bit set in *addr?
  53  * test_and_set_bit(bit, addr)          Set bit and return old value
  54  * test_and_clear_bit(bit, addr)        Clear bit and return old value
  55  * test_and_change_bit(bit, addr)       Change bit and return old value
  56  * find_first_zero_bit(addr, nbits)     Position first zero bit in *addr
  57  * find_first_bit(addr, nbits)          Position first set bit in *addr
  58  * find_next_zero_bit(addr, nbits, bit) Position next zero bit in *addr >= bit
  59  * find_next_bit(addr, nbits, bit)      Position next set bit in *addr >= bit
  60  */
  61
  62 #define BITMAP_LAST_WORD_MASK(nbits)                                    \
  63     (                                                                   \
  64         ((nbits) % BITS_PER_LONG) ?                                     \
  65         (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL                       \
  66         )
  67
  68 #define DECLARE_BITMAP(name,bits)                  \
  69         unsigned long name[BITS_TO_LONGS(bits)]
  70
  71 #define small_nbits(nbits)                      \
  72         ((nbits) <= BITS_PER_LONG)
  73
  74 int slow_bitmap_empty(const unsigned long *bitmap, long bits);
  75 int slow_bitmap_full(const unsigned long *bitmap, long bits);
  76 int slow_bitmap_equal(const unsigned long *bitmap1,
  77                       const unsigned long *bitmap2, long bits);
  78 void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
  79                             long bits);
  80 void slow_bitmap_shift_right(unsigned long *dst,
  81                              const unsigned long *src, int shift, long bits);
  82 void slow_bitmap_shift_left(unsigned long *dst,
  83                             const unsigned long *src, int shift, long bits);
  84 int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
  85                     const unsigned long *bitmap2, long bits);
  86 void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
  87                     const unsigned long *bitmap2, long bits);
  88 void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
  89                      const unsigned long *bitmap2, long bits);
  90 int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
  91                        const unsigned long *bitmap2, long bits);
  92 int slow_bitmap_intersects(const unsigned long *bitmap1,
  93                            const unsigned long *bitmap2, long bits);
  94
  95 static inline unsigned long *bitmap_try_new(long nbits)
  96 {
  97     long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
  98     return g_try_malloc0(len);
  99 }
 100
 101 static inline unsigned long *bitmap_new(long nbits)
 102 {
 103     unsigned long *ptr = bitmap_try_new(nbits);
 104     if (ptr == NULL) {
 105         abort();
 106     }
 107     return ptr;
 108 }
 109
 110 static inline void bitmap_zero(unsigned long *dst, long nbits)
 111 {
 112     if (small_nbits(nbits)) {
 113         *dst = 0UL;
 114     } else {
 115         long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 116         memset(dst, 0, len);
 117     }
 118 }
 119
 120 static inline void bitmap_fill(unsigned long *dst, long nbits)
 121 {
 122     size_t nlongs = BITS_TO_LONGS(nbits);
 123     if (!small_nbits(nbits)) {
 124         long len = (nlongs - 1) * sizeof(unsigned long);
 125         memset(dst, 0xff,  len);
 126     }
 127     dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
 128 }
 129
 130 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
 131                                long nbits)
 132 {
 133     if (small_nbits(nbits)) {
 134         *dst = *src;
 135     } else {
 136         long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 137         memcpy(dst, src, len);
 138     }
 139 }
 140
 141 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
 142                              const unsigned long *src2, long nbits)
 143 {
 144     if (small_nbits(nbits)) {
 145         return (*dst = *src1 & *src2) != 0;
 146     }
 147     return slow_bitmap_and(dst, src1, src2, nbits);
 148 }
 149
 150 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
 151                              const unsigned long *src2, long nbits)
 152 {
 153     if (small_nbits(nbits)) {
 154         *dst = *src1 | *src2;
 155     } else {
 156         slow_bitmap_or(dst, src1, src2, nbits);
 157     }
 158 }
 159
 160 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
 161                               const unsigned long *src2, long nbits)
 162 {
 163     if (small_nbits(nbits)) {
 164         *dst = *src1 ^ *src2;
 165     } else {
 166         slow_bitmap_xor(dst, src1, src2, nbits);
 167     }
 168 }
 169
 170 static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
 171                                 const unsigned long *src2, long nbits)
 172 {
 173     if (small_nbits(nbits)) {
 174         return (*dst = *src1 & ~(*src2)) != 0;
 175     }
 176     return slow_bitmap_andnot(dst, src1, src2, nbits);
 177 }
 178
 179 static inline void bitmap_complement(unsigned long *dst,
 180                                      const unsigned long *src,
 181                                      long nbits)
 182 {
 183     if (small_nbits(nbits)) {
 184         *dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
 185     } else {
 186         slow_bitmap_complement(dst, src, nbits);
 187     }
 188 }
 189
 190 static inline int bitmap_equal(const unsigned long *src1,
 191                                const unsigned long *src2, long nbits)
 192 {
 193     if (small_nbits(nbits)) {
 194         return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
 195     } else {
 196         return slow_bitmap_equal(src1, src2, nbits);
 197     }
 198 }
 199
 200 static inline int bitmap_empty(const unsigned long *src, long nbits)
 201 {
 202     if (small_nbits(nbits)) {
 203         return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
 204     } else {
 205         return slow_bitmap_empty(src, nbits);
 206     }
 207 }
 208
 209 static inline int bitmap_full(const unsigned long *src, long nbits)
 210 {
 211     if (small_nbits(nbits)) {
 212         return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
 213     } else {
 214         return slow_bitmap_full(src, nbits);
 215     }
 216 }
 217
 218 static inline int bitmap_intersects(const unsigned long *src1,
 219                                     const unsigned long *src2, long nbits)
 220 {
 221     if (small_nbits(nbits)) {
 222         return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 223     } else {
 224         return slow_bitmap_intersects(src1, src2, nbits);
 225     }
 226 }
 227
 228 void bitmap_set(unsigned long *map, long i, long len);
 229 void bitmap_clear(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 */