| /* Copyright 2016 IBM Corp. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
| * implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| #include "bitmap.h" |
| |
| static int __bitmap_find_bit(bitmap_t map, unsigned int start, unsigned int count, |
| bool value) |
| { |
| unsigned int el, first_bit; |
| unsigned int end = start + count; |
| bitmap_elem_t e, ev; |
| int b; |
| |
| ev = value ? -1ul : 0; |
| el = BITMAP_ELEM(start); |
| first_bit = BITMAP_BIT(start); |
| |
| while (start < end) { |
| e = map[el] ^ ev; |
| e |= ((1ul << first_bit) - 1); |
| if (~e) |
| break; |
| start = (start + BITMAP_ELSZ) & ~(BITMAP_ELSZ - 1); |
| first_bit = 0; |
| el++; |
| } |
| for (b = first_bit; b < BITMAP_ELSZ && start < end; b++,start++) { |
| if ((e & (1ull << b)) == 0) |
| return start; |
| } |
| |
| return -1; |
| } |
| |
| int bitmap_find_zero_bit(bitmap_t map, unsigned int start, unsigned int count) |
| { |
| return __bitmap_find_bit(map, start, count, false); |
| } |
| |
| int bitmap_find_one_bit(bitmap_t map, unsigned int start, unsigned int count) |
| { |
| return __bitmap_find_bit(map, start, count, true); |
| } |
| |