74 lines
2.1 KiB
C++
74 lines
2.1 KiB
C++
/*
|
|
* Copyright (C) 2020-present ScyllaDB
|
|
*/
|
|
|
|
/*
|
|
* This file is part of Scylla.
|
|
*
|
|
* Scylla is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU Affero General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* Scylla is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <cstdint>
|
|
#include <limits>
|
|
|
|
namespace utils {
|
|
|
|
static constexpr int64_t simple_key_unused_value = std::numeric_limits<int64_t>::min();
|
|
|
|
/*
|
|
* array_search_gt(value, array, capacity, size)
|
|
*
|
|
* Returns the index of the first element in the array that's greater
|
|
* than the given value.
|
|
*
|
|
* To accomodate the single-instruction-multiple-data variant, observe
|
|
* the following:
|
|
* - capacity must be a multiple of 4
|
|
* - any items with indexes in [size, capacity) must be initialized
|
|
* to std::numeric_limits<int64_t>::min()
|
|
*/
|
|
int array_search_gt(int64_t val, const int64_t* array, const int capacity, const int size);
|
|
|
|
static inline unsigned array_search_4_eq(uint8_t val, const uint8_t* array) {
|
|
// Unrolled loop is few %s faster
|
|
if (array[0] == val) {
|
|
return 0;
|
|
} else if (array[1] == val) {
|
|
return 1;
|
|
} else if (array[2] == val) {
|
|
return 2;
|
|
} else if (array[3] == val) {
|
|
return 3;
|
|
} else {
|
|
return 4;
|
|
}
|
|
}
|
|
|
|
static inline unsigned array_search_8_eq(uint8_t val, const uint8_t* array) {
|
|
for (unsigned i = 0; i < 8; i++) {
|
|
if (array[i] == val) {
|
|
return i;
|
|
}
|
|
}
|
|
return 8;
|
|
}
|
|
|
|
unsigned array_search_16_eq(uint8_t val, const uint8_t* array);
|
|
unsigned array_search_32_eq(uint8_t val, const uint8_t* array);
|
|
unsigned array_search_x32_eq(uint8_t val, const uint8_t* array, int nr);
|
|
|
|
}
|