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
|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
namespace System.IO
{
/// <summary>Contains internal path helpers that are shared between many projects.</summary>
internal static partial class PathInternal
{
/// <summary>
/// Returns true if the path ends in a directory separator.
/// </summary>
internal static bool EndsInDirectorySeparator(ReadOnlySpan<char> path)
=> path.Length > 0 && IsDirectorySeparator(path[path.Length - 1]);
/// <summary>
/// Returns true if the path starts in a directory separator.
/// </summary>
internal static bool StartsWithDirectorySeparator(ReadOnlySpan<char> path) => path.Length > 0 && IsDirectorySeparator(path[0]);
internal static string EnsureTrailingSeparator(string path)
=> EndsInDirectorySeparator(path) ? path : path + DirectorySeparatorCharAsString;
internal static string TrimEndingDirectorySeparator(string path) =>
EndsInDirectorySeparator(path) && !IsRoot(path) ?
path.Substring(0, path.Length - 1) :
path;
internal static ReadOnlySpan<char> TrimEndingDirectorySeparator(ReadOnlySpan<char> path) =>
EndsInDirectorySeparator(path) && !IsRoot(path) ?
path.Slice(0, path.Length - 1) :
path;
internal static bool IsRoot(ReadOnlySpan<char> path)
=> path.Length == GetRootLength(path);
/// <summary>
/// Get the common path length from the start of the string.
/// </summary>
internal static int GetCommonPathLength(string first, string second, bool ignoreCase)
{
int commonChars = EqualStartingCharacterCount(first, second, ignoreCase: ignoreCase);
// If nothing matches
if (commonChars == 0)
return commonChars;
// Or we're a full string and equal length or match to a separator
if (commonChars == first.Length
&& (commonChars == second.Length || IsDirectorySeparator(second[commonChars])))
return commonChars;
if (commonChars == second.Length && IsDirectorySeparator(first[commonChars]))
return commonChars;
// It's possible we matched somewhere in the middle of a segment e.g. C:\Foodie and C:\Foobar.
while (commonChars > 0 && !IsDirectorySeparator(first[commonChars - 1]))
commonChars--;
return commonChars;
}
/// <summary>
/// Gets the count of common characters from the left optionally ignoring case
/// </summary>
unsafe internal static int EqualStartingCharacterCount(string first, string second, bool ignoreCase)
{
if (string.IsNullOrEmpty(first) || string.IsNullOrEmpty(second)) return 0;
int commonChars = 0;
fixed (char* f = first)
fixed (char* s = second)
{
char* l = f;
char* r = s;
char* leftEnd = l + first.Length;
char* rightEnd = r + second.Length;
while (l != leftEnd && r != rightEnd
&& (*l == *r || (ignoreCase && char.ToUpperInvariant((*l)) == char.ToUpperInvariant((*r)))))
{
commonChars++;
l++;
r++;
}
}
return commonChars;
}
/// <summary>
/// Returns true if the two paths have the same root
/// </summary>
internal static bool AreRootsEqual(string first, string second, StringComparison comparisonType)
{
int firstRootLength = GetRootLength(first);
int secondRootLength = GetRootLength(second);
return firstRootLength == secondRootLength
&& string.Compare(
strA: first,
indexA: 0,
strB: second,
indexB: 0,
length: firstRootLength,
comparisonType: comparisonType) == 0;
}
}
}
|
