102 lines
3.9 KiB
Swift
102 lines
3.9 KiB
Swift
//===----------------------------------------------------------------------===//
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//
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// This source file is part of the SwiftNIO open source project
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//
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// Copyright (c) 2021 Apple Inc. and the SwiftNIO project authors
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// Licensed under Apache License v2.0
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//
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// See LICENSE.txt for license information
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// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
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//
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// SPDX-License-Identifier: Apache-2.0
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//
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//===----------------------------------------------------------------------===//
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@usableFromInline
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enum _IntegerBitPacking {}
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extension _IntegerBitPacking {
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@inlinable
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static func packUU<Left: FixedWidthInteger & UnsignedInteger,
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Right: FixedWidthInteger & UnsignedInteger,
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Result: FixedWidthInteger & UnsignedInteger>(_ left: Left,
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_ right: Right,
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type: Result.Type = Result.self) -> Result {
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assert(MemoryLayout<Left>.size + MemoryLayout<Right>.size <= MemoryLayout<Result>.size)
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let resultLeft = Result(left)
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let resultRight = Result(right)
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let result = (resultLeft << Right.bitWidth) | resultRight
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assert(result.nonzeroBitCount == left.nonzeroBitCount + right.nonzeroBitCount)
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return result
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}
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@inlinable
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static func unpackUU<Input: FixedWidthInteger & UnsignedInteger,
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Left: FixedWidthInteger & UnsignedInteger,
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Right: FixedWidthInteger & UnsignedInteger>(_ input: Input,
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leftType: Left.Type = Left.self,
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rightType: Right.Type = Right.self) -> (Left, Right) {
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assert(MemoryLayout<Left>.size + MemoryLayout<Right>.size <= MemoryLayout<Input>.size)
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let leftMask = Input(Left.max)
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let rightMask = Input(Right.max)
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let right = input & rightMask
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let left = (input >> Right.bitWidth) & leftMask
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assert(input.nonzeroBitCount == left.nonzeroBitCount + right.nonzeroBitCount)
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return (Left(left), Right(right))
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}
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}
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@usableFromInline
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enum IntegerBitPacking {}
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extension IntegerBitPacking {
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@inlinable
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static func packUInt32UInt16UInt8(_ left: UInt32, _ middle: UInt16, _ right: UInt8) -> UInt64 {
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return _IntegerBitPacking.packUU(
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_IntegerBitPacking.packUU(right, middle, type: UInt32.self),
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left
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)
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}
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@inlinable
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static func unpackUInt32UInt16UInt8(_ value: UInt64) -> (UInt32, UInt16, UInt8) {
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let leftRight = _IntegerBitPacking.unpackUU(value, leftType: UInt32.self, rightType: UInt32.self)
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let left = _IntegerBitPacking.unpackUU(leftRight.0, leftType: UInt8.self, rightType: UInt16.self)
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return (leftRight.1, left.1, left.0)
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}
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@inlinable
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static func packUInt8UInt8(_ left: UInt8, _ right: UInt8) -> UInt16 {
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return _IntegerBitPacking.packUU(left, right)
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}
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@inlinable
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static func unpackUInt8UInt8(_ value: UInt16) -> (UInt8, UInt8) {
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return _IntegerBitPacking.unpackUU(value)
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}
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@inlinable
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static func packUInt16UInt8(_ left: UInt16, _ right: UInt8) -> UInt32 {
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return _IntegerBitPacking.packUU(left, right)
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}
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@inlinable
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static func unpackUInt16UInt8(_ value: UInt32) -> (UInt16, UInt8) {
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return _IntegerBitPacking.unpackUU(value)
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}
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@inlinable
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static func packUInt32CInt(_ left: UInt32, _ right: CInt) -> UInt64 {
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return _IntegerBitPacking.packUU(left, UInt32(truncatingIfNeeded: right))
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}
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@inlinable
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static func unpackUInt32CInt(_ value: UInt64) -> (UInt32, CInt) {
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let unpacked = _IntegerBitPacking.unpackUU(value, leftType: UInt32.self, rightType: UInt32.self)
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return (unpacked.0, CInt(truncatingIfNeeded: unpacked.1))
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}
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}
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