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_set_atomic(dst, pos, nbits)   Set specified bit area with atomic ops
  43  * bitmap_clear(dst, pos, nbits)                Clear specified bit area
  44  * bitmap_test_and_clear_atomic(dst, pos, nbits)    Test and clear area
  45  * bitmap_find_next_zero_area(buf, len, pos, n, mask)   Find bit free area
  46  */
  47
  48 /*
  49  * Also the following operations apply to bitmaps.
  50  *
  51  * set_bit(bit, addr)                   *addr |= bit
  52  * clear_bit(bit, addr)                 *addr &= ~bit
  53  * change_bit(bit, addr)                *addr ^= bit
  54  * test_bit(bit, addr)                  Is bit set in *addr?
  55  * test_and_set_bit(bit, addr)          Set bit and return old value
  56  * test_and_clear_bit(bit, addr)        Clear bit and return old value
  57  * test_and_change_bit(bit, addr)       Change bit and return old value
  58  * find_first_zero_bit(addr, nbits)     Position first zero bit in *addr
  59  * find_first_bit(addr, nbits)          Position first set bit in *addr
  60  * find_next_zero_bit(addr, nbits, bit) Position next zero bit in *addr >= bit
  61  * find_next_bit(addr, nbits, bit)      Position next set bit in *addr >= bit
  62  */
  63
  64 #define BITMAP_LAST_WORD_MASK(nbits)                                    \
  65     (                                                                   \
  66         ((nbits) % BITS_PER_LONG) ?                                     \
  67         (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL                       \
  68         )
  69
  70 #define DECLARE_BITMAP(name,bits)                  \
  71         unsigned long name[BITS_TO_LONGS(bits)]
  72
  73 #define small_nbits(nbits)                      \
  74         ((nbits) <= BITS_PER_LONG)
  75
  76 int slow_bitmap_empty(const unsigned long *bitmap, long bits);
  77 int slow_bitmap_full(const unsigned long *bitmap, long bits);
  78 int slow_bitmap_equal(const unsigned long *bitmap1,
  79                       const unsigned long *bitmap2, long bits);
  80 void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
  81                             long bits);
  82 void slow_bitmap_shift_right(unsigned long *dst,
  83                              const unsigned long *src, int shift, long bits);
  84 void slow_bitmap_shift_left(unsigned long *dst,
  85                             const unsigned long *src, int shift, long bits);
  86 int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
  87                     const unsigned long *bitmap2, long bits);
  88 void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
  89                     const unsigned long *bitmap2, long bits);
  90 void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
  91                      const unsigned long *bitmap2, long bits);
  92 int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
  93                        const unsigned long *bitmap2, long bits);
  94 int slow_bitmap_intersects(const unsigned long *bitmap1,
  95                            const unsigned long *bitmap2, long bits);
  96
  97 static inline unsigned long *bitmap_try_new(long nbits)
  98 {
  99     long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 100     return g_try_malloc0(len);
 101 }
 102
 103 static inline unsigned long *bitmap_new(long nbits)
 104 {
 105     unsigned long *ptr = bitmap_try_new(nbits);
 106     if (ptr == NULL) {
 107         abort();
 108     }
 109     return ptr;
 110 }
 111
 112 static inline void bitmap_zero(unsigned long *dst, long nbits)
 113 {
 114     if (small_nbits(nbits)) {
 115         *dst = 0UL;
 116     } else {
 117         long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 118         memset(dst, 0, len);
 119     }
 120 }
 121
 122 static inline void bitmap_fill(unsigned long *dst, long nbits)
 123 {
 124     size_t nlongs = BITS_TO_LONGS(nbits);
 125     if (!small_nbits(nbits)) {
 126         long len = (nlongs - 1) * sizeof(unsigned long);
 127         memset(dst, 0xff,  len);
 128     }
 129     dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
 130 }
 131
 132 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
 133                                long nbits)
 134 {
 135     if (small_nbits(nbits)) {
 136         *dst = *src;
 137     } else {
 138         long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 139         memcpy(dst, src, len);
 140     }
 141 }
 142
 143 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
 144                              const unsigned long *src2, long nbits)
 145 {
 146     if (small_nbits(nbits)) {
 147         return (*dst = *src1 & *src2) != 0;
 148     }
 149     return slow_bitmap_and(dst, src1, src2, nbits);
 150 }
 151
 152 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
 153                              const unsigned long *src2, long nbits)
 154 {
 155     if (small_nbits(nbits)) {
 156         *dst = *src1 | *src2;
 157     } else {
 158         slow_bitmap_or(dst, src1, src2, nbits);
 159     }
 160 }
 161
 162 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
 163                               const unsigned long *src2, long nbits)
 164 {
 165     if (small_nbits(nbits)) {
 166         *dst = *src1 ^ *src2;
 167     } else {
 168         slow_bitmap_xor(dst, src1, src2, nbits);
 169     }
 170 }
 171
 172 static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
 173                                 const unsigned long *src2, long nbits)
 174 {
 175     if (small_nbits(nbits)) {
 176         return (*dst = *src1 & ~(*src2)) != 0;
 177     }
 178     return slow_bitmap_andnot(dst, src1, src2, nbits);
 179 }
 180
 181 static inline void bitmap_complement(unsigned long *dst,
 182                                      const unsigned long *src,
 183                                      long nbits)
 184 {
 185     if (small_nbits(nbits)) {
 186         *dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
 187     } else {
 188         slow_bitmap_complement(dst, src, nbits);
 189     }
 190 }
 191
 192 static inline int bitmap_equal(const unsigned long *src1,
 193                                const unsigned long *src2, long nbits)
 194 {
 195     if (small_nbits(nbits)) {
 196         return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
 197     } else {
 198         return slow_bitmap_equal(src1, src2, nbits);
 199     }
 200 }
 201
 202 static inline int bitmap_empty(const unsigned long *src, long nbits)
 203 {
 204     if (small_nbits(nbits)) {
 205         return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
 206     } else {
 207         return slow_bitmap_empty(src, nbits);
 208     }
 209 }
 210
 211 static inline int bitmap_full(const unsigned long *src, long nbits)
 212 {
 213     if (small_nbits(nbits)) {
 214         return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
 215     } else {
 216         return slow_bitmap_full(src, nbits);
 217     }
 218 }
 219
 220 static inline int bitmap_intersects(const unsigned long *src1,
 221                                     const unsigned long *src2, long nbits)
 222 {
 223     if (small_nbits(nbits)) {
 224         return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 225     } else {
 226         return slow_bitmap_intersects(src1, src2, nbits);
 227     }
 228 }
 229
 230 void bitmap_set(unsigned long *map, long i, long len);
 231 void bitmap_set_atomic(unsigned long *map, long i, long len);
 232 void bitmap_clear(unsigned long *map, long start, long nr);
 233 bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr);
 234 unsigned long bitmap_find_next_zero_area(unsigned long *map,
 235                                          unsigned long size,
 236                                          unsigned long start,
 237                                          unsigned long nr,
 238                                          unsigned long align_mask);
 239
 240 static inline unsigned long *bitmap_zero_extend(unsigned long *old,
 241                                                 long old_nbits, long new_nbits)
 242 {
 243     long new_len = BITS_TO_LONGS(new_nbits) * sizeof(unsigned long);
 244     unsigned long *new = g_realloc(old, new_len);
 245     bitmap_clear(new, old_nbits, new_nbits - old_nbits);
 246     return new;
 247 }
 248
 249 #endif /* BITMAP_H */