diff options
Diffstat (limited to 'sys/sys/bitstring.h')
| -rw-r--r-- | sys/sys/bitstring.h | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/sys/sys/bitstring.h b/sys/sys/bitstring.h index a8c8a4e2a396..b411b8961e0f 100644 --- a/sys/sys/bitstring.h +++ b/sys/sys/bitstring.h @@ -275,6 +275,84 @@ bit_ffc(bitstr_t *_bitstr, int _nbits, int *_result) bit_ffc_at(_bitstr, /*start*/0, _nbits, _result); } +/* Find contiguous sequence of at least size set bits at or after start */ +static inline void +bit_ffs_area_at(bitstr_t *_bitstr, int _start, int _nbits, int _size, int *_result) +{ + int _index, _end, _i; +again: + /* Find the first set bit */ + bit_ffs_at(_bitstr, _start, _nbits, &_index); + if (_index < 0) { + *_result = -1; + return; + } + + /* Make sure there is enough room left in the bitstr */ + _end = _index + _size; + if (_end > _nbits) { + *_result = -1; + return; + } + + /* Find the next cleared bit starting at _index, stopping at _end */ + bit_ffc_at(_bitstr, _index, _end, &_i); + if (_i >= 0) { + /* we found a clear bit between _index and _end, so skip ahead + * to the next bit and try again + */ + _start = _i + 1; + goto again; + } + *_result = _index; +} + +/* Find contiguous sequence of at least size cleared bits at or after start */ +static inline void +bit_ffc_area_at(bitstr_t *_bitstr, int _start, int _nbits, int _size, int *_result) +{ + int _index, _end, _i; +again: + /* Find the first zero bit */ + bit_ffc_at(_bitstr, _start, _nbits, &_index); + if (_index < 0) { + *_result = -1; + return; + } + + /* Make sure there is enough room left in the bitstr */ + _end = _index + _size; + if (_end > _nbits) { + *_result = -1; + return; + } + + /* Find the next set bit starting at _index, stopping at _end */ + bit_ffs_at(_bitstr, _index, _end, &_i); + if (_i >= 0) { + /* we found a set bit between _index and _end, so skip ahead + * to the next bit and try again + */ + _start = _i + 1; + goto again; + } + *_result = _index; +} + +/* Find contiguous sequence of at least size set bits in bit string */ +static inline void +bit_ffs_area(bitstr_t *_bitstr, int _nbits, int _size, int *_result) +{ + bit_ffs_area_at(_bitstr, /*start*/0, _nbits, _size, _result); +} + +/* Find contiguous sequence of at least size cleared bits in bit string */ +static inline void +bit_ffc_area(bitstr_t *_bitstr, int _nbits, int _size, int *_result) +{ + bit_ffc_area_at(_bitstr, /*start*/0, _nbits, _size, _result); +} + /* Count the number of bits set in a bitstr of size _nbits at or after _start */ static inline void bit_count(bitstr_t *_bitstr, int _start, int _nbits, int *_result) |