// 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.
public static string NormalizeInternal(string inPath)
{
// Relative paths aren't a thing for IFileSystem, so assume all paths are absolute
// and add a '/' to the beginning of the path if it doesn't already begin with one
if (inPath.Length == 0 || !IsDirectorySeparator(inPath[0]))
{
inPath = DirectorySeparator + inPath;
}
ReadOnlySpan <char> path = inPath.AsSpan();
if (path.Length == 0)
{
return(DirectorySeparator.ToString());
}
Span <char> initialBuffer = stackalloc char[0x200];
var sb = new ValueStringBuilder(initialBuffer);
for (int i = 0; i < path.Length; i++)
{
char c = path[i];
if (IsDirectorySeparator(c) && i + 1 < path.Length)
{
// Skip this character if it's a directory separator and if the next character is, too,
// e.g. "parent//child" => "parent/child"
if (IsDirectorySeparator(path[i + 1]))
{
continue;
}
// Skip this character and the next if it's referring to the current directory,
// e.g. "parent/./child" => "parent/child"
if (IsCurrentDirectory(path, i))
{
i++;
continue;
}
// Skip this character and the next two if it's referring to the parent directory,
// e.g. "parent/child/../grandchild" => "parent/grandchild"
if (IsParentDirectory(path, i))
{
// Unwind back to the last slash (and if there isn't one, clear out everything).
for (int s = sb.Length - 1; s >= 0; s--)
{
if (IsDirectorySeparator(sb[s]))
{
sb.Length = s;
break;
}
}
i += 2;
continue;
}
}
sb.Append(c);
}
// If we haven't changed the source path, return the original
if (sb.Length == inPath.Length)
{
return(inPath);
}
if (sb.Length == 0)
{
sb.Append(DirectorySeparator);
}
return(sb.ToString());
}
// 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.
internal static bool NormalizeInternal(ReadOnlySpan <char> path, int rootLength, ref ValueStringBuilder sb)
{
if (rootLength > 0)
{
sb.Append(path.Slice(0, rootLength));
}
bool isNormalized = true;
var state = NormalizeState.Initial;
for (int i = rootLength; i < path.Length; i++)
{
char c = path[i];
switch (state)
{
case NormalizeState.Initial when IsDirectorySeparator(c):
state = NormalizeState.Delimiter;
sb.Append(c);
break;
case NormalizeState.Initial when c == '.':
isNormalized = false;
state = NormalizeState.Dot;
sb.Append(DirectorySeparator);
sb.Append(c);
break;
case NormalizeState.Initial:
isNormalized = false;
state = NormalizeState.Normal;
sb.Append(DirectorySeparator);
sb.Append(c);
break;
case NormalizeState.Normal when IsDirectorySeparator(c):
state = NormalizeState.Delimiter;
sb.Append(c);
break;
case NormalizeState.Normal:
sb.Append(c);
break;
case NormalizeState.Delimiter when IsDirectorySeparator(c):
isNormalized = false;
break;
case NormalizeState.Delimiter when c == '.':
state = NormalizeState.Dot;
sb.Append(c);
break;
case NormalizeState.Delimiter:
state = NormalizeState.Normal;
sb.Append(c);
break;
case NormalizeState.Dot when IsDirectorySeparator(c):
isNormalized = false;
state = NormalizeState.Delimiter;
sb.Length -= 1;
break;
case NormalizeState.Dot when c == '.':
state = NormalizeState.DoubleDot;
sb.Append(c);
break;
case NormalizeState.Dot:
state = NormalizeState.Normal;
sb.Append(c);
break;
case NormalizeState.DoubleDot when IsDirectorySeparator(c):
isNormalized = false;
state = NormalizeState.Delimiter;
int s = sb.Length - 1;
int separators = 0;
for (; s > rootLength; s--)
{
if (IsDirectorySeparator(sb[s]))
{
separators++;
if (separators == 2)
{
break;
}
}
}
sb.Length = s + 1;
break;
case NormalizeState.DoubleDot:
state = NormalizeState.Normal;
break;
}
}
switch (state)
{
case NormalizeState.Dot:
isNormalized = false;
sb.Length -= 2;
break;
case NormalizeState.DoubleDot:
isNormalized = false;
int s = sb.Length - 1;
int separators = 0;
for (; s > rootLength; s--)
{
if (IsDirectorySeparator(sb[s]))
{
separators++;
if (separators == 2)
{
break;
}
}
}
sb.Length = s;
break;
}
if (sb.Length == rootLength)
{
sb.Append(DirectorySeparator);
return(false);
}
return(isNormalized);
}