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| 1 | +//===----------------------------------------------------------------------===// |
| 2 | +// |
| 3 | +// This source file is part of the RediStack open source project |
| 4 | +// |
| 5 | +// Copyright (c) 2023 RediStack project authors |
| 6 | +// Licensed under Apache License v2.0 |
| 7 | +// |
| 8 | +// See LICENSE.txt for license information |
| 9 | +// See CONTRIBUTORS.txt for the list of RediStack project authors |
| 10 | +// |
| 11 | +// SPDX-License-Identifier: Apache-2.0 |
| 12 | +// |
| 13 | +//===----------------------------------------------------------------------===// |
| 14 | + |
| 15 | +typealias HashSlots = [ClosedRange<RedisHashSlot>] |
| 16 | + |
| 17 | +/// A wrapper around UInt16 that represents a Redis HashSlot. A HashSlot determines which |
| 18 | +/// Shard to connect to in a Redis Cluster. |
| 19 | +public struct RedisHashSlot: Hashable, Sendable { |
| 20 | + /// An unknown `HashSlot` value |
| 21 | + public static let unknown = RedisHashSlot(.max) |
| 22 | + |
| 23 | + /// The max valid `HashSlot` value |
| 24 | + public static let max = RedisHashSlot(16383) |
| 25 | + /// The min valid `HashSlot` value |
| 26 | + public static let min = RedisHashSlot(0) |
| 27 | + /// The number of all hash slots |
| 28 | + public static let count: Int = 16384 |
| 29 | + |
| 30 | + private var _raw: UInt16 |
| 31 | + |
| 32 | + private init(_ value: UInt16) { |
| 33 | + precondition(value < 16384 || value == .max) |
| 34 | + self._raw = value |
| 35 | + } |
| 36 | +} |
| 37 | + |
| 38 | +extension RedisHashSlot: Comparable { |
| 39 | + public static func < (lhs: RedisHashSlot, rhs: RedisHashSlot) -> Bool { |
| 40 | + lhs.rawValue < rhs.rawValue |
| 41 | + } |
| 42 | +} |
| 43 | + |
| 44 | +extension RedisHashSlot: RawRepresentable { |
| 45 | + public typealias RawValue = UInt16 |
| 46 | + |
| 47 | + public init?(rawValue: UInt16) { |
| 48 | + guard rawValue < 16384 else { return nil } |
| 49 | + self._raw = rawValue |
| 50 | + } |
| 51 | + |
| 52 | + public init?(rawValue: Int) { |
| 53 | + guard rawValue >= 0, rawValue < 16384 else { return nil } |
| 54 | + self._raw = UInt16(rawValue) |
| 55 | + } |
| 56 | + |
| 57 | + public var rawValue: UInt16 { self._raw } |
| 58 | +} |
| 59 | + |
| 60 | +extension RedisHashSlot: Strideable { |
| 61 | + public typealias Stride = Int |
| 62 | + |
| 63 | + public func distance(to other: RedisHashSlot) -> Int { |
| 64 | + Int(other.rawValue - self.rawValue) |
| 65 | + } |
| 66 | + |
| 67 | + public func advanced(by n: Int) -> RedisHashSlot { |
| 68 | + // we are fine that this might crash. Same behavior as normal Int and friends. |
| 69 | + RedisHashSlot(UInt16(Int(self.rawValue) + n)) |
| 70 | + } |
| 71 | +} |
| 72 | + |
| 73 | +extension RedisHashSlot: ExpressibleByIntegerLiteral { |
| 74 | + public typealias IntegerLiteralType = UInt16 |
| 75 | + |
| 76 | + public init(integerLiteral value: UInt16) { |
| 77 | + precondition(value < 16384 || value == .max) |
| 78 | + self._raw = value |
| 79 | + } |
| 80 | +} |
| 81 | + |
| 82 | +extension RedisHashSlot: CustomStringConvertible { |
| 83 | + public var description: String { |
| 84 | + switch self { |
| 85 | + case RedisHashSlot.min...RedisHashSlot.max: |
| 86 | + return "\(self.rawValue)" |
| 87 | + case RedisHashSlot.unknown: |
| 88 | + return "unknown" |
| 89 | + default: |
| 90 | + fatalError("Invalid value: \(self._raw)") |
| 91 | + } |
| 92 | + } |
| 93 | +} |
| 94 | + |
| 95 | +extension RedisHashSlot { |
| 96 | + /// Creates a slot for a given `key`. A ``HashSlot`` is used to determine which shard to connect to. |
| 97 | + /// - Parameter key: The key used in a redis command |
| 98 | + public init(key: String) { |
| 99 | + // Banging is safe because the modulo ensures we are in range |
| 100 | + self.init(rawValue: UInt16(crc16(RedisHashSlot.hashTag(forKey: key)) % 16384))! |
| 101 | + } |
| 102 | + |
| 103 | + /// Computes the range of the key that is used to compute the slot for a given key |
| 104 | + /// - Parameter key: The key for your operation |
| 105 | + /// - Returns: A substring utf8 view that shall be used in the crc16 computation |
| 106 | + static func hashTag(forKey key: String) -> Substring.UTF8View { |
| 107 | + let utf8View = key.utf8 |
| 108 | + |
| 109 | + var firstOpenCurly: String.UTF8View.Index? |
| 110 | + var index = utf8View.startIndex |
| 111 | + |
| 112 | + while index < utf8View.endIndex { |
| 113 | + defer { index = utf8View.index(after: index) } |
| 114 | + |
| 115 | + switch utf8View[index] { |
| 116 | + case UInt8(ascii: "{") where firstOpenCurly == nil: |
| 117 | + firstOpenCurly = index |
| 118 | + case UInt8(ascii: "}"): |
| 119 | + guard let firstOpenCurly = firstOpenCurly else { |
| 120 | + continue |
| 121 | + } |
| 122 | + |
| 123 | + if firstOpenCurly == utf8View.index(before: index) { |
| 124 | + // we had a `{}` combination... this means the complete key shall be used for hashing |
| 125 | + return utf8View[...] |
| 126 | + } |
| 127 | + |
| 128 | + return utf8View[(utf8View.index(after: firstOpenCurly))..<index] |
| 129 | + default: |
| 130 | + continue |
| 131 | + } |
| 132 | + } |
| 133 | + |
| 134 | + return utf8View[...] |
| 135 | + } |
| 136 | +} |
| 137 | + |
| 138 | +/* |
| 139 | + * Copyright 2001-2010 Georges Menie (www.menie.org) |
| 140 | + * Copyright 2010 Salvatore Sanfilippo (adapted to Redis coding style) |
| 141 | + * All rights reserved. |
| 142 | + * Redistribution and use in source and binary forms, with or without |
| 143 | + * modification, are permitted provided that the following conditions are met: |
| 144 | + * |
| 145 | + * * Redistributions of source code must retain the above copyright |
| 146 | + * notice, this list of conditions and the following disclaimer. |
| 147 | + * * Redistributions in binary form must reproduce the above copyright |
| 148 | + * notice, this list of conditions and the following disclaimer in the |
| 149 | + * documentation and/or other materials provided with the distribution. |
| 150 | + * * Neither the name of the University of California, Berkeley nor the |
| 151 | + * names of its contributors may be used to endorse or promote products |
| 152 | + * derived from this software without specific prior written permission. |
| 153 | + * |
| 154 | + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY |
| 155 | + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| 156 | + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| 157 | + * DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY |
| 158 | + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 159 | + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| 160 | + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| 161 | + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 162 | + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 163 | + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 164 | + */ |
| 165 | + |
| 166 | +/* CRC16 implementation according to CCITT standards. |
| 167 | + * |
| 168 | + * Note by @antirez: this is actually the XMODEM CRC 16 algorithm, using the |
| 169 | + * following parameters: |
| 170 | + * |
| 171 | + * Name : "XMODEM", also known as "ZMODEM", "CRC-16/ACORN" |
| 172 | + * Width : 16 bit |
| 173 | + * Poly : 1021 (That is actually x^16 + x^12 + x^5 + 1) |
| 174 | + * Initialization : 0000 |
| 175 | + * Reflect Input byte : False |
| 176 | + * Reflect Output CRC : False |
| 177 | + * Xor constant to output CRC : 0000 |
| 178 | + * Output for "123456789" : 31C3 |
| 179 | + */ |
| 180 | + |
| 181 | +let crc16tab: [UInt16] = [ |
| 182 | + 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, |
| 183 | + 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, |
| 184 | + 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, |
| 185 | + 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, |
| 186 | + 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, |
| 187 | + 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, |
| 188 | + 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, |
| 189 | + 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, |
| 190 | + 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, |
| 191 | + 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, |
| 192 | + 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, |
| 193 | + 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, |
| 194 | + 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, |
| 195 | + 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, |
| 196 | + 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, |
| 197 | + 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, |
| 198 | + 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, |
| 199 | + 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, |
| 200 | + 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, |
| 201 | + 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, |
| 202 | + 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, |
| 203 | + 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, |
| 204 | + 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, |
| 205 | + 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, |
| 206 | + 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, |
| 207 | + 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, |
| 208 | + 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, |
| 209 | + 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, |
| 210 | + 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, |
| 211 | + 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, |
| 212 | + 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, |
| 213 | + 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0, |
| 214 | +] |
| 215 | + |
| 216 | +func crc16<Bytes: Sequence>(_ bytes: Bytes) -> UInt16 where Bytes.Element == UInt8 { |
| 217 | + var crc: UInt16 = 0 |
| 218 | + for byte in bytes { |
| 219 | + crc = (crc &<< 8) ^ crc16tab[(Int(crc &>> 8) ^ Int(byte)) & 0x00FF] |
| 220 | + } |
| 221 | + return crc |
| 222 | +} |
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