44 lines
979 B
C
44 lines
979 B
C
// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
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/* Copyright 2016 IBM Corp. */
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#include "bitmap.h"
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static int __bitmap_find_bit(bitmap_t map, unsigned int start, unsigned int count,
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bool value)
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{
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unsigned int el, first_bit;
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unsigned int end = start + count;
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bitmap_elem_t e, ev;
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int b;
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ev = value ? -1ul : 0;
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el = BITMAP_ELEM(start);
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first_bit = BITMAP_BIT(start);
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while (start < end) {
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e = map[el] ^ ev;
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e |= ((1ul << first_bit) - 1);
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if (~e)
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break;
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start = (start + BITMAP_ELSZ) & ~(BITMAP_ELSZ - 1);
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first_bit = 0;
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el++;
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}
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for (b = first_bit; b < BITMAP_ELSZ && start < end; b++,start++) {
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if ((e & (1ull << b)) == 0)
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return start;
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}
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return -1;
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}
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int bitmap_find_zero_bit(bitmap_t map, unsigned int start, unsigned int count)
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{
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return __bitmap_find_bit(map, start, count, false);
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}
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int bitmap_find_one_bit(bitmap_t map, unsigned int start, unsigned int count)
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{
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return __bitmap_find_bit(map, start, count, true);
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}
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