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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
/*
* Copyright (c) 2024 Vaughn Nugent
*
* Library: VNLib
* Package: VNLib.Utils
* File: SubSequence.cs
*
* SubSequence.cs is part of VNLib.Utils which is part of the larger
* VNLib collection of libraries and utilities.
*
* VNLib.Utils is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published
* by the Free Software Foundation, either version 2 of the License,
* or (at your option) any later version.
*
* VNLib.Utils 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 VNLib.Utils. If not, see http://www.gnu.org/licenses/.
*/
using System;
using VNLib.Utils.Extensions;
namespace VNLib.Utils.Memory
{
/// <summary>
/// Represents a subset (or window) of data within a <see cref="IMemoryHandle{T}"/>
/// </summary>
/// <typeparam name="T">The unmanaged type to wrap</typeparam>
public readonly record struct SubSequence<T>
{
readonly nuint _offset;
/// <summary>
/// The handle that owns the memory block
/// </summary>
public readonly IMemoryHandle<T> Handle { get; }
/// <summary>
/// The number of elements in the current sequence
/// </summary>
public readonly int Size { get; }
/// <summary>
/// Creates a new <see cref="SubSequence{T}"/> to the handle to get a window of the block
/// </summary>
/// <param name="block"></param>
/// <param name="offset"></param>
/// <param name="size"></param>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public SubSequence(IMemoryHandle<T> block, nuint offset, int size)
{
ArgumentNullException.ThrowIfNull(block);
ArgumentOutOfRangeException.ThrowIfNegative(size);
//Check handle bounds
MemoryUtil.CheckBounds(block, offset, (uint)size);
Size = size;
Handle = block;
_offset = offset;
}
/// <summary>
/// Gets a <see cref="Span{T}"/> that is offset from the base of the handle
/// and the size of the current sequence
/// </summary>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public readonly Span<T> Span => Size > 0 ? Handle.GetOffsetSpan(_offset, Size) : Span<T>.Empty;
/// <summary>
/// Gets a reference to the first element in the current sequence
/// </summary>
/// <returns>The element reference</returns>
public readonly ref T GetReference() => ref Handle.GetOffsetRef(_offset);
/// <summary>
/// Slices the current sequence into a smaller <see cref="SubSequence{T}"/>
/// </summary>
/// <param name="offset">The relative offset from the current window offset</param>
/// <param name="size">The size of the block</param>
/// <returns>A <see cref="SubSequence{T}"/> of the current sequence</returns>
/// <exception cref="OverflowException"></exception>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public readonly SubSequence<T> Slice(nuint offset, int size)
{
//Calc offset
nuint newOffset = checked(_offset + offset);
//Cal max size after the slice
int newMaxSize = Size - (int)offset;
ArgumentOutOfRangeException.ThrowIfNegative(offset);
ArgumentOutOfRangeException.ThrowIfGreaterThan(size, newMaxSize);
return new SubSequence<T>(Handle, newOffset, size > newMaxSize ? newMaxSize : size);
}
/// <summary>
/// Slices the current sequence into a smaller <see cref="SubSequence{T}"/>
/// </summary>
/// <param name="offset">The relative offset from the current window offset</param>
/// <returns>A <see cref="SubSequence{T}"/> of the current sequence</returns>
public readonly SubSequence<T> Slice(nuint offset)
{
//Calc offset
nuint newOffset = _offset + offset;
//Calc the new max size of the block (let constructor handle the exception if less than 0)
int newMaxSize = (int)((nuint)Size - offset);
return new SubSequence<T>(Handle, newOffset, newMaxSize);
}
}
}
|
