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/**
* Copyright (C) 2021-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <cmath>
#include <iostream>
#include <vector>
namespace mongo {
/**
* As of now, Simple8b is a static class that can encode a series of integers and a selector value
* into a single 64 bit Simple8b word.
*/
class Simple8b {
public:
// A valid Simple8b should never have a selector value of 1, so we will use it as an error code.
static const uint64_t errCode = 0x1000000000000000;
/**
* encodeSimple8b takes a selector and a vector of integers to be compressed into a 64 bit word.
* If there are wasted bits, it will be at the very right side.
* For now, we will assume that all ints in the vector are greater or equal to zero.
* We will also assume that the selector and all values will fit into the 64 bit word.
* Returns the encoded Simple8b word if the inputs are valid and errCode otherwise.
*/
static uint64_t encodeSimple8b(uint8_t selector, const std::vector<uint64_t>& values);
/**
* decodeSimple8b decodes a simple8b word into a vector of integers.
* Only when the selector is invalid will the returned vector be empty.
*/
static std::vector<uint64_t> decodeSimple8b(uint64_t simple8bWord);
};
} // namespace mongo
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