4 * @author Sebastian Hack
5 * @brief A bitset implementation.
8 #ifndef __FIRM_BITSET_H
9 #define __FIRM_BITSET_H
17 #include "bitfiddle.h"
19 #include "bitset_std.h"
21 #if defined(__GNUC__) && defined(__i386__)
22 #include "bitset_ia32.h"
25 typedef struct _bitset_t {
30 #define BS_UNIT_SIZE sizeof(unsigned long)
31 #define BS_UNIT_SIZE_BITS (BS_UNIT_SIZE * 8)
32 #define BS_UNIT_MASK (BS_UNIT_SIZE_BITS - 1)
35 * Initialize a bitset.
36 * This functions should not be called.
38 * Note that this function needs three macros which must be provided by the
39 * bitfield implementor:
40 * - _bitset_overall_size(highest_bit) The overall size that must be
41 * allocated for the bitfield in bytes.
42 * - _bitset_units(highest_bit) The number of units that will be
43 * present in the bitfield for a given highest bit.
44 * - _bitset_data_ptr(data, highest_bit) This produces as pointer to the
45 * first unit in the allocated memory area. The main reason for this
46 * macro is, that some bitset implementors want control over memory
49 * @param area A pointer to memory reserved for the bitset.
50 * @param units The number of units that are allocated for the bitset.
51 * @return A pointer to the initialized bitset.
53 static INLINE bitset_t *_bitset_prepare(void *area, unsigned long highest_bit)
56 memset(area, 0, _bitset_overall_size(sizeof(bitset_t), highest_bit));
57 ptr->units = _bitset_units(highest_bit);
58 ptr->data = _bitset_data_ptr(area, sizeof(bitset_t), highest_bit);
63 * Get the capacity of the bitset in bits.
64 * @param bs The bitset.
65 * @return The capacity in bits of the bitset.
67 #define bitset_capacity(bs) ((bs)->units * BS_UNIT_SIZE_BITS)
70 * Allocate a bitset on an obstack.
71 * @param obst The obstack.
72 * @param highest_bit The greatest bit that shall be stored in the set.
73 * @return A pointer to an empty initialized bitset.
75 #define bitset_obstack_alloc(obst,highest_bit) \
76 _bitset_prepare(obstack_alloc(obst, _bitset_overall_size(sizeof(bitset_t), highest_bit)), highest_bit)
79 * Allocate a bitset via malloc.
80 * @param highest_bit The greatest bit that shall be stored in the set.
81 * @return A pointer to an empty initialized bitset.
83 #define bitset_malloc(highest_bit) \
84 _bitset_prepare(malloc(_bitset_overall_size(sizeof(bitset_t), highest_bit)), highest_bit)
87 * Free a bitset allocated with bitset_malloc().
88 * @param bs The bitset.
90 #define bitset_free(bs) free(bs)
93 * Allocate a bitset on the stack via alloca.
94 * @param highest_bit The greatest bit that shall be stored in the set.
95 * @return A pointer to an empty initialized bitset.
97 #define bitset_alloca(highest_bit) \
98 _bitset_prepare(alloca(_bitset_overall_size(sizeof(bitset_t), highest_bit)), highest_bit)
102 * Get the unit which contains a specific bit.
103 * This function is internal.
104 * @param bs The bitset.
105 * @param bit The bit.
106 * @return A pointer to the unit containing the bit.
108 static INLINE unsigned long *_bitset_get_unit(const bitset_t *bs, unsigned long bit)
110 assert(bit < bs->units * BS_UNIT_SIZE_BITS && "Bit too large");
111 return bs->data + bit / BS_UNIT_SIZE_BITS;
115 * Set a bit in the bitset.
116 * @param bs The bitset.
117 * @param bit The bit to set.
119 static INLINE void bitset_set(bitset_t *bs, unsigned long bit)
121 unsigned long *unit = _bitset_get_unit(bs, bit);
122 _bitset_inside_set(*unit, bit & BS_UNIT_MASK);
126 * Clear a bit in the bitset.
127 * @param bs The bitset.
128 * @param bit The bit to clear.
130 static INLINE void bitset_clear(bitset_t *bs, unsigned long bit)
132 unsigned long *unit = _bitset_get_unit(bs, bit);
133 _bitset_inside_clear(unit, bit & BS_UNIT_MASK);
136 static INLINE int bitset_is_set(const bitset_t *bs, unsigned long bit)
138 unsigned long *unit = _bitset_get_unit(bs, bit);
139 return _bitset_inside_is_set(unit, bit & BS_UNIT_MASK);
143 * Flip a bit in a bitset.
144 * @param bs The bitset.
145 * @param bit The bit to flip.
147 static INLINE void bitset_flip(bitset_t *bs, unsigned long bit)
149 unsigned long *unit = _bitset_get_unit(bs, bit);
150 _bitset_inside_flip(unit, bit & BS_UNIT_MASK);
154 * Copy a bitset to another.
155 * @param tgt The target bitset.
156 * @param src The source bitset.
157 * @return The target bitset.
159 static INLINE bitset_t *bitset_copy(bitset_t *tgt, const bitset_t *src)
161 unsigned long tu = tgt->units;
162 unsigned long su = src->units;
163 unsigned long min_units = tu < su ? tu : su;
164 memcpy(tgt->data, src->data, min_units * BS_UNIT_SIZE);
166 memset(tgt->data + min_units, 0, BS_UNIT_SIZE * (tu - min_units));
171 * Find the smallest bit set in the bitset.
172 * @param bs The bitset.
173 * @return The smallest bit set in the bitset.
175 static INLINE unsigned long bitset_min(const bitset_t *bs)
177 unsigned long i, ofs = 0;
179 for(i = 0; i < bs->units; ++i) {
180 unsigned long *unit = &bs->data[i];
181 unsigned long pos = _bitset_inside_ntz(unit);
184 ofs += BS_UNIT_SIZE_BITS;
191 * Find the greatest bit set in the bitset.
192 * @param bs The bitset.
193 * @return The greatest bit set in the bitset.
195 static INLINE unsigned long bitset_max(const bitset_t *bs)
197 unsigned long i, max = 0, ofs = 0;
199 for(i = 0; i < bs->units; ++i) {
200 unsigned long *unit = &bs->data[i];
201 unsigned long pos = _bitset_inside_nlz(unit);
204 ofs += BS_UNIT_SIZE_BITS;
211 * Find the next set bit from a given bit.
212 * @note Note that if pos is set, pos is returned.
213 * @param bs The bitset.
214 * @param pos The bit from which to search for the next set bit.
215 * @return The next set bit from pos on, or -1, if no set bit was found
218 static INLINE unsigned long _bitset_next(const bitset_t *bs,
219 unsigned long pos, int set)
221 unsigned long unit_number = pos / BS_UNIT_SIZE_BITS;
222 unsigned long bit_in_unit = pos & BS_UNIT_MASK;
223 unsigned long in_unit_mask = (1 << bit_in_unit) - 1;
226 * Mask out the bits smaller than pos in the current unit.
227 * We are only interested in bits set higher than pos.
229 unsigned long curr_unit = bs->data[unit_number] & ~in_unit_mask;
231 /* Find the next bit set in the unit. */
232 unsigned long next_in_this_unit
233 = _bitset_inside_ntz_value(set ? curr_unit : ~curr_unit);
235 /* If there is a bit set in the current unit, exit. */
236 if(next_in_this_unit < BS_UNIT_SIZE_BITS)
237 return next_in_this_unit + unit_number * BS_UNIT_SIZE_BITS;
239 /* Else search for set bits in the next units. */
242 for(i = unit_number + 1; i < bs->units; ++i) {
243 unsigned long data = bs->data[i];
244 unsigned long first_set = _bitset_inside_ntz_value(set ? data : ~data);
245 if(first_set < BS_UNIT_SIZE_BITS)
246 return first_set + i * BS_UNIT_SIZE_BITS;
253 #define bitset_next_clear(bs,pos) _bitset_next((bs), (pos), 0)
254 #define bitset_next_set(bs,pos) _bitset_next((bs), (pos), 1)
257 * Convenience macro for bitset iteration.
258 * @param bitset The bitset.
259 * @param elm A unsigned long variable.
261 #define bitset_foreach(bitset,elm) \
262 for(elm = bitset_next_set(bitset,0); elm != -1; elm = bitset_next_set(bitset,elm+1))
265 * Count the bits set.
266 * This can also be seen as the cardinality of the set.
267 * @param bs The bitset.
268 * @return The number of bits set in the bitset.
270 static INLINE unsigned long bitset_popcnt(const bitset_t *bs)
272 unsigned long i, pop = 0;
275 for(i = 0, unit = bs->data; i < bs->units; ++i, ++unit)
276 pop += _bitset_inside_pop(unit);
283 * This sets all bits to zero.
284 * @param bs The bitset.
286 static INLINE void bitset_clear_all(bitset_t *bs)
288 memset(bs->data, 0, BS_UNIT_SIZE * bs->units);
292 * Check, if one bitset is contained by another.
293 * That is, each bit set in lhs is also set in rhs.
294 * @param lhs A bitset.
295 * @param rhs Another bitset.
296 * @return 1, if all bits in lhs are also set in rhs, 0 otherwise.
298 static INLINE int bitset_contains(const bitset_t *lhs, const bitset_t *rhs)
300 unsigned long n = lhs->units < rhs->units ? lhs->units : rhs->units;
303 for(i = 0; i < n; ++i) {
304 unsigned long lu = lhs->data[i];
305 unsigned long ru = rhs->data[i];
312 * If the left hand sinde is a larger bitset than rhs,
313 * we have to check, that all extra bits in lhs are 0
316 for(i = n; i < lhs->units; ++i) {
317 if(lhs->data[i] != 0)
326 * Print a bitset to a stream.
327 * The bitset is printed as a comma seperated list of bits set.
328 * @param file The stream.
329 * @param bs The bitset.
331 static INLINE void bitset_fprint(FILE *file, bitset_t *bs)
333 const char *prefix = "";
337 for(i = bitset_next_set(bs, 0); i != -1; i = bitset_next_set(bs, i + 1)) {
338 fprintf(file, "%s%u", prefix, i);
345 * Here, the binary operations follow.
346 * And, Or, And Not, Xor are available.
349 #define BINARY_OP(op) \
350 static INLINE bitset_t *bitset_ ## op(bitset_t *tgt, const bitset_t *src) \
353 int n = tgt->units > src->units ? src->units : tgt->units; \
354 for(i = 0; i < n; i += _BITSET_BINOP_UNITS_INC) \
355 _bitset_inside_binop_ ## op(&tgt->data[i], &src->data[i]); \
356 for(i = n; i < tgt->units; i += _BITSET_BINOP_UNITS_INC) \
357 _bitset_inside_binop_with_zero_ ## op(&tgt->data[i]); \