File: IntegerBitPacking.swift

package info (click to toggle)
swiftlang 6.1.3-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 2,791,532 kB
  • sloc: cpp: 9,901,743; ansic: 2,201,431; asm: 1,091,827; python: 308,252; objc: 82,166; f90: 80,126; lisp: 38,358; pascal: 25,559; sh: 20,429; ml: 5,058; perl: 4,745; makefile: 4,484; awk: 3,535; javascript: 3,018; xml: 918; fortran: 664; cs: 573; ruby: 396
file content (103 lines) | stat: -rw-r--r-- 3,989 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2021 Apple Inc. and the SwiftNIO project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//

// FIXME: Duplicated in NIO.

@usableFromInline
enum _IntegerBitPacking {}

extension _IntegerBitPacking {
    @inlinable
    static func packUU<Left: FixedWidthInteger & UnsignedInteger,
                       Right: FixedWidthInteger & UnsignedInteger,
                       Result: FixedWidthInteger & UnsignedInteger>(_ left: Left,
                                                                    _ right: Right,
                                                                    type: Result.Type = Result.self) -> Result {
        assert(MemoryLayout<Left>.size + MemoryLayout<Right>.size <= MemoryLayout<Result>.size)

        let resultLeft = Result(left)
        let resultRight = Result(right)
        let result = (resultLeft << Right.bitWidth) | resultRight
        assert(result.nonzeroBitCount == left.nonzeroBitCount + right.nonzeroBitCount)
        return result
    }

    @inlinable
    static func unpackUU<Input: FixedWidthInteger & UnsignedInteger,
                         Left: FixedWidthInteger & UnsignedInteger,
                         Right: FixedWidthInteger & UnsignedInteger>(_ input: Input,
                                                                     leftType: Left.Type = Left.self,
                                                                     rightType: Right.Type = Right.self) -> (Left, Right) {
        assert(MemoryLayout<Left>.size + MemoryLayout<Right>.size <= MemoryLayout<Input>.size)

        let leftMask = Input(Left.max)
        let rightMask = Input(Right.max)
        let right = input & rightMask
        let left = (input >> Right.bitWidth) & leftMask

        assert(input.nonzeroBitCount == left.nonzeroBitCount + right.nonzeroBitCount)
        return (Left(left), Right(right))
    }
}

@usableFromInline
enum IntegerBitPacking {}

extension IntegerBitPacking {
    @inlinable
    static func packUInt32UInt16UInt8(_ left: UInt32, _ middle: UInt16, _ right: UInt8) -> UInt64 {
        return _IntegerBitPacking.packUU(
            _IntegerBitPacking.packUU(right, middle, type: UInt32.self),
            left
        )
    }

    @inlinable
    static func unpackUInt32UInt16UInt8(_ value: UInt64) -> (UInt32, UInt16, UInt8) {
        let leftRight = _IntegerBitPacking.unpackUU(value, leftType: UInt32.self, rightType: UInt32.self)
        let left = _IntegerBitPacking.unpackUU(leftRight.0, leftType: UInt8.self, rightType: UInt16.self)
        return (leftRight.1, left.1, left.0)
    }

    @inlinable
    static func packUInt8UInt8(_ left: UInt8, _ right: UInt8) -> UInt16 {
        return _IntegerBitPacking.packUU(left, right)
    }

    @inlinable
    static func unpackUInt8UInt8(_ value: UInt16) -> (UInt8, UInt8) {
        return _IntegerBitPacking.unpackUU(value)
    }

    @inlinable
    static func packUInt16UInt8(_ left: UInt16, _ right: UInt8) -> UInt32 {
        return _IntegerBitPacking.packUU(left, right)
    }

    @inlinable
    static func unpackUInt16UInt8(_ value: UInt32) -> (UInt16, UInt8) {
        return _IntegerBitPacking.unpackUU(value)
    }

    @inlinable
    static func packUInt32CInt(_ left: UInt32, _ right: CInt) -> UInt64 {
        return _IntegerBitPacking.packUU(left, UInt32(truncatingIfNeeded: right))
    }

    @inlinable
    static func unpackUInt32CInt(_ value: UInt64) -> (UInt32, CInt) {
        let unpacked = _IntegerBitPacking.unpackUU(value, leftType: UInt32.self, rightType: UInt32.self)
        return (unpacked.0, CInt(truncatingIfNeeded: unpacked.1))
    }
}