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65 lines
1.0 KiB
65 lines
1.0 KiB
#include <stdint.h>
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#include <bitops.h>
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#include <macros.h>
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#define BIT_WORD(n) ((n) / BIT_SIZE(unsigned long))
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#define BIT_MASK(n) (1UL << ((n) % BIT_SIZE(unsigned long)))
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unsigned ilog2(unsigned n)
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{
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unsigned ret = 0;
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while (n >>= 1)
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++ret;
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return ret;
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}
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int is_bit_set(void *base, size_t n)
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{
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unsigned long *word = (unsigned long *)base + BIT_WORD(n);
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unsigned long mask = BIT_MASK(n);
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return (*word & mask) ? 1 : 0;
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}
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void set_bit(void *base, size_t n)
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{
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unsigned long *word = (unsigned long *)base + BIT_WORD(n);
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unsigned long mask = BIT_MASK(n);
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*word |= mask;
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}
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void clear_bit(void *base, size_t n)
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{
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unsigned long *word = (unsigned long *)base + BIT_WORD(n);
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unsigned long mask = BIT_MASK(n);
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*word &= ~mask;
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}
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size_t next_set_bit(void *base, size_t n)
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{
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size_t i;
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for (i = 0; i < n; ++i) {
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if (is_bit_set(base, i))
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return i;
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}
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return SIZE_MAX;
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}
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size_t next_clear_bit(void *base, size_t n)
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{
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size_t i;
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for (i = 0; i < n; ++i) {
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if (!is_bit_set(base, i))
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return i;
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}
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return SIZE_MAX;
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}
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