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July 6, 2010 10:35
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| /* bitmaps and bitmap operations */ | |
| #ifndef _BITMAPS_H_ | |
| #define _BITMAPS_H_ | |
| /* | |
| * Bitmaps are arrays of unsigned ints, filled with bits in most- | |
| * significant-first order. So bitmap[0] shall contain the bits from | |
| * 0 to 31 on a 32bit architecture, bitmap[1] - 32-63, and so forth. | |
| * | |
| * The callers are responsible to do all the bounds-checking. | |
| */ | |
| enum { BITS_PER_BITMAP_ELEM = 8 * sizeof(unsigned) }; | |
| typedef unsigned bitmap_elem_t; | |
| /* returned will be the unshifted bit. IOW: NOT 0 or 1, but something | |
| * like 0x00001000 or 0x40000000 */ | |
| static inline | |
| bitmap_elem_t bitmap_test_bit(const bitmap_elem_t* bits, unsigned bit) | |
| { | |
| if ( sizeof(*bits) == 4 ) | |
| return bits[bit >> 5] & (0x80000000 >> (bit & 0x1f)); | |
| else if ( sizeof(*bits) == 8 ) | |
| return bits[bit >> 6] & (0x8000000000000000ull >> (bit & 0x3f)); | |
| else | |
| { | |
| return bits[bit / BITS_PER_BITMAP_ELEM] & | |
| 1 << ((BITS_PER_BITMAP_ELEM - bit % BITS_PER_BITMAP_ELEM) - 1); | |
| } | |
| } | |
| static inline | |
| bitmap_elem_t bitmap_set_bit(bitmap_elem_t* bits, unsigned bit) | |
| { | |
| if ( sizeof(*bits) == 4 ) | |
| return bits[bit >> 5] |= (0x80000000 >> (bit & 0x1f)); | |
| else if ( sizeof(*bits) == 8 ) | |
| return bits[bit >> 6] |= (0x8000000000000000ull >> (bit & 0x3f)); | |
| else | |
| { | |
| return bits[bit / BITS_PER_BITMAP_ELEM] |= | |
| 1 << ((BITS_PER_BITMAP_ELEM - bit % BITS_PER_BITMAP_ELEM) - 1); | |
| } | |
| } | |
| static inline | |
| bitmap_elem_t bitmap_clear_bit(bitmap_elem_t* bits, unsigned bit) | |
| { | |
| if ( sizeof(*bits) == 4 ) | |
| return bits[bit >> 5] &= ~(0x80000000 >> (bit & 0x1f)); | |
| else if ( sizeof(*bits) == 8 ) | |
| return bits[bit >> 6] &= ~(0x8000000000000000ull >> (bit & 0x3f)); | |
| else | |
| { | |
| return bits[bit / BITS_PER_BITMAP_ELEM] &= | |
| ~(1 << ((BITS_PER_BITMAP_ELEM - bit % BITS_PER_BITMAP_ELEM) - 1)); | |
| } | |
| } | |
| /* pos must position the bits inside of a bitmap element, otherwise | |
| * the index shift puts the bits in the wrong word (for simplicity). | |
| * Only low 8 bits of b8 shall be used */ | |
| static inline | |
| void bitmap_set_8bits_fast(bitmap_elem_t* bits, unsigned pos, unsigned b8) | |
| { | |
| if ( sizeof(*bits) == 4 ) | |
| bits[pos >> 5] |= b8 << (24 - (pos & 0x1f)); | |
| else if ( sizeof(*bits) == 8 ) | |
| bits[pos >> 6] |= b8 << (56 - (pos & 0x3f)); | |
| else | |
| { | |
| bits[pos / BITS_PER_BITMAP_ELEM] |= | |
| b8 << (BITS_PER_BITMAP_ELEM - 8 - pos % BITS_PER_BITMAP_ELEM); | |
| } | |
| } | |
| #endif /* _BITMAPS_H_ */ |
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