xref: /qemu/include/qemu/bitmap.h (revision 7271a819) 
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  * bitmap_to_le(dst, src, nbits)      Convert bitmap to little endian
43  * bitmap_from_le(dst, src, nbits)    Convert bitmap from little endian
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_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
63 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
64 
65 #define DECLARE_BITMAP(name,bits)                  \
66         unsigned long name[BITS_TO_LONGS(bits)]
67 
68 #define small_nbits(nbits)                      \
69         ((nbits) <= BITS_PER_LONG)
70 
71 int slow_bitmap_empty(const unsigned long *bitmap, long bits);
72 int slow_bitmap_full(const unsigned long *bitmap, long bits);
73 int slow_bitmap_equal(const unsigned long *bitmap1,
74                       const unsigned long *bitmap2, long bits);
75 void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
76                             long bits);
77 int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
78                     const unsigned long *bitmap2, long bits);
79 void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
80                     const unsigned long *bitmap2, long bits);
81 void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
82                      const unsigned long *bitmap2, long bits);
83 int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
84                        const unsigned long *bitmap2, long bits);
85 int slow_bitmap_intersects(const unsigned long *bitmap1,
86                            const unsigned long *bitmap2, long bits);
87 long slow_bitmap_count_one(const unsigned long *bitmap, long nbits);
88 
89 static inline unsigned long *bitmap_try_new(long nbits)
90 {
91     long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
92     return g_try_malloc0(len);
93 }
94 
95 static inline unsigned long *bitmap_new(long nbits)
96 {
97     unsigned long *ptr = bitmap_try_new(nbits);
98     if (ptr == NULL) {
99         abort();
100     }
101     return ptr;
102 }
103 
104 static inline void bitmap_zero(unsigned long *dst, long nbits)
105 {
106     if (small_nbits(nbits)) {
107         *dst = 0UL;
108     } else {
109         long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
110         memset(dst, 0, len);
111     }
112 }
113 
114 static inline void bitmap_fill(unsigned long *dst, long nbits)
115 {
116     size_t nlongs = BITS_TO_LONGS(nbits);
117     if (!small_nbits(nbits)) {
118         long len = (nlongs - 1) * sizeof(unsigned long);
119         memset(dst, 0xff,  len);
120     }
121     dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
122 }
123 
124 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
125                                long nbits)
126 {
127     if (small_nbits(nbits)) {
128         *dst = *src;
129     } else {
130         long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
131         memcpy(dst, src, len);
132     }
133 }
134 
135 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
136                              const unsigned long *src2, long nbits)
137 {
138     if (small_nbits(nbits)) {
139         return (*dst = *src1 & *src2) != 0;
140     }
141     return slow_bitmap_and(dst, src1, src2, nbits);
142 }
143 
144 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
145                              const unsigned long *src2, long nbits)
146 {
147     if (small_nbits(nbits)) {
148         *dst = *src1 | *src2;
149     } else {
150         slow_bitmap_or(dst, src1, src2, nbits);
151     }
152 }
153 
154 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
155                               const unsigned long *src2, long nbits)
156 {
157     if (small_nbits(nbits)) {
158         *dst = *src1 ^ *src2;
159     } else {
160         slow_bitmap_xor(dst, src1, src2, nbits);
161     }
162 }
163 
164 static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
165                                 const unsigned long *src2, long nbits)
166 {
167     if (small_nbits(nbits)) {
168         return (*dst = *src1 & ~(*src2)) != 0;
169     }
170     return slow_bitmap_andnot(dst, src1, src2, nbits);
171 }
172 
173 static inline void bitmap_complement(unsigned long *dst,
174                                      const unsigned long *src,
175                                      long nbits)
176 {
177     if (small_nbits(nbits)) {
178         *dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
179     } else {
180         slow_bitmap_complement(dst, src, nbits);
181     }
182 }
183 
184 static inline int bitmap_equal(const unsigned long *src1,
185                                const unsigned long *src2, long nbits)
186 {
187     if (small_nbits(nbits)) {
188         return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
189     } else {
190         return slow_bitmap_equal(src1, src2, nbits);
191     }
192 }
193 
194 static inline int bitmap_empty(const unsigned long *src, long nbits)
195 {
196     if (small_nbits(nbits)) {
197         return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
198     } else {
199         return slow_bitmap_empty(src, nbits);
200     }
201 }
202 
203 static inline int bitmap_full(const unsigned long *src, long nbits)
204 {
205     if (small_nbits(nbits)) {
206         return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
207     } else {
208         return slow_bitmap_full(src, nbits);
209     }
210 }
211 
212 static inline int bitmap_intersects(const unsigned long *src1,
213                                     const unsigned long *src2, long nbits)
214 {
215     if (small_nbits(nbits)) {
216         return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
217     } else {
218         return slow_bitmap_intersects(src1, src2, nbits);
219     }
220 }
221 
222 static inline long bitmap_count_one(const unsigned long *bitmap, long nbits)
223 {
224     if (small_nbits(nbits)) {
225         return ctpopl(*bitmap & BITMAP_LAST_WORD_MASK(nbits));
226     } else {
227         return slow_bitmap_count_one(bitmap, nbits);
228     }
229 }
230 
231 void bitmap_set(unsigned long *map, long i, long len);
232 void bitmap_set_atomic(unsigned long *map, long i, long len);
233 void bitmap_clear(unsigned long *map, long start, long nr);
234 bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr);
235 void bitmap_copy_and_clear_atomic(unsigned long *dst, unsigned long *src,
236                                   long nr);
237 unsigned long bitmap_find_next_zero_area(unsigned long *map,
238                                          unsigned long size,
239                                          unsigned long start,
240                                          unsigned long nr,
241                                          unsigned long align_mask);
242 
243 static inline unsigned long *bitmap_zero_extend(unsigned long *old,
244                                                 long old_nbits, long new_nbits)
245 {
246     long new_len = BITS_TO_LONGS(new_nbits) * sizeof(unsigned long);
247     unsigned long *new = g_realloc(old, new_len);
248     bitmap_clear(new, old_nbits, new_nbits - old_nbits);
249     return new;
250 }
251 
252 void bitmap_to_le(unsigned long *dst, const unsigned long *src,
253                   long nbits);
254 void bitmap_from_le(unsigned long *dst, const unsigned long *src,
255                     long nbits);
256 
257 #endif /* BITMAP_H */
258