C# path examples

path_examples.cs

using System;
using System.IO;
using System.Linq;
using System.Diagnostics;

namespace HelloWorld { class Program {

// Info: {fullyQualified, root, fullPath}

// Traditional path test cases:
static string[] traditionalPaths = {
    // {false, nil, <unchanged>}
    @"",

    // {false, nil, C:\Users\User\Documents\PathExplorer\C}
    @"C",

    // {false, C:,  C:\Users\User\Documents\PathExplorer}
    @"C:",

    // {true,  C:\, <unchanged>}
    @"C:\",

    // {false, nil, C:\Users\User\Documents\PathExplorer\ABC:\}
    @"ABC:\",

    // {false, nil, C:\Users\User\Documents\PathExplorer\:\}
    @":\",

    // {false, nil, <unchanged>}
    @"1:\",

    // {true,  C:\, <unchanged>}
    @"C:\foo\bar.exe",

    // {false, C:,  C:\Users\User\Documents\PathExplorer\foo\bar}
    @"C:foo\bar",

    // {false, \,   C:\foo\bar.exe}
    @"\foo\bar.exe",

    // {false, nil, C:\Users\User\Documents\PathExplorer\foo\bar.exe}
    @"foo\bar.exe",

    // {false, \,   C:\}
    @"\",

    // {false, \,   C:\}
    @"/",

    // {true,  c:\, c:\}
    @"c:/",

    // {true,  c:\, c:\foo\bar\}
    @"c:/foo/bar/",

};

// UNC path test cases:
static string[] uncPaths = {
    // {true,  \\server\share,       <unchanged>}
    @"\\server\share\",

    // {true,  \\server\share,       <unchanged>}
    @"\\server\share",

    // {true,  \\server\share,       <unchanged>}
    @"\\server\share\folder\file.txt",

    // {true,  \\server\,            <unchanged>}
    @"\\server\",

    // {true,  \\server,             <unchanged>}
    @"\\server",

    // {true,  \\system07\C$,        <unchanged>}
    @"\\system07\C$\foo",

    // {true,  \\system07\ABC$,      <unchanged>}
    @"\\system07\ABC$\foo",

    // {true,  \\system07\ABC:,      <unchanged>}
    @"\\system07\ABC:\foo",

    // {true,  \\system07\ABC,       <unchanged>}
    @"\\system07\ABC\foo",

    // {true,  \\system07\C:,        <unchanged>}
    @"\\system07\C:\foo",

    // {true,  \\server1\util,       <unchanged>}
    @"\\server1\util\file\",

    // {true,  \\server1\e:,         \\server1\e:\util\file\}
    @"\\server1\e:\util\\file\",

    // {true,  \\.\UNC\server\share, <unchanged>}
    @"\\.\UNC\server\share\foo",

    // {true,  \\.\UNC\Server\Share, <unchanged>}
    @"\\.\UNC\Server\Share\Test\Foo.txt",

    // {true,  \\server,             <unchanged>}
    @"\\server",

    // {true,  \\server\,            <unchanged>}
    @"\\server\",

    // {true,  \\server\,            \\server\}
    @"\\server\\",

    // {true,  \\server\,            \\server\folder}
    @"\\server\\folder",

    // {true,  \\server\x,           <unchanged>}
    @"\\server\x\folder",

    // {true,  \\server\,            \\server\folder\file.txt}
    @"\\server\\folder\file.txt",

    // {true,  \\,                   <unchanged>}
    @"\\",

    // {true,  \\x,                  <unchanged>}
    @"\\x",

    // {true,  \\,                   <unchanged>}
    @"\\\",

    // {true,  \\,                   \\\}
    @"\\\\",

    // {true,  \\,                   \\}
    @"//",

    // {true,  \\server\share,       \\server\share}
    @"//server/share",

    // {true,  \\server\share,       \\server\share\file}
    @"//server/share/file",

    // {true,  \\server\,            \\server\file}
    @"//server//file",

    // {true,  \\server\,            \\server\file}
    @"/\server//file",

    // {true,  \\.hidden\file,       <unchanged>}
    @"\\.hidden\file",

    // {true,  \\?question\file,     <unchanged>}
    @"\\?question\file",
};

// DOS device path test cases:
static string[] devicePaths = {
    // {true,  \\.\volume\,  <unchanged>}
    @"\\.\volume\foo",

    // {true,  \\.\C:\,      <unchanged>}
    @"\\.\C:\Test\Foo.txt",

    // {true,  \\?\C:\,      <unchanged>}
    @"\\?\C:\Test\Foo.txt",

    // {true,  \\?\C$\,      <unchanged>}
    @"\\?\C$\Test\Foo.txt",

    // {true,  \\?\C:foo\,   <unchanged>}
    @"\\?\C:foo\Foo.txt",

    // {true,  \\?\C$foo\,   <unchanged>}
    @"\\?\C$foo\Foo.txt",

    // {true,  \\?\server1\, <unchanged>}
    @"\\?\server1\e:\util\\file\",

    // {true,  \\?\server1\, <unchanged>}
    @"\\?\server1\util\\file\",

    // {true,  \\?\server1\, <unchanged>}
    @"\\?\server1\util\file\",

    // {true,  \\.\CON,      <unchanged>}
    @"\\.\CON",

    // {true,  \\.\CON\,     <unchanged>}
    @"\\.\CON\",

    // {true,  \\.\LPT1,     <unchanged>}
    @"\\.\LPT1",

    // {true,  \\.\COM1,     <unchanged>}
    @"\\.\COM1",

    // {true,  \\.,          \\.\}
    @"\\.",

    // {true,  \\.\,         <unchanged>}
    @"\\.\",

    // {true,  \\.\vol,      <unchanged>}
    @"\\.\vol",

};

// DOS device GUID-volume path test cases:
static string[] guidPaths = {
    // {true,  \\.\Volume{b75e2c83-0000-0000-0000-602f00000000}\, <unchanged>}
    @"\\.\Volume{b75e2c83-0000-0000-0000-602f00000000}\Test\Foo.txt",

    // {true,  \\?\Volume{b75e2c83-0000-0000-0000-602f00000000}\, <unchanged>}
    @"\\?\Volume{b75e2c83-0000-0000-0000-602f00000000}\Test\Foo.txt",

    // {true,  \\server\Volume{b75e2c83-0000-0000-0000-602f00000000},       <unchanged>}
    @"\\server\Volume{b75e2c83-0000-0000-0000-602f00000000}\Test\Foo.txt",

    // {true,  \\.\UNC\server\Volume{b75e2c83-0000-0000-0000-602f00000000}, <unchanged>}
    @"\\.\UNC\server\Volume{b75e2c83-0000-0000-0000-602f00000000}\Test\Foo.txt",
};

// Legacy DOS device path test cases:
static string[] legacyDevicePaths = {
    // {false, nil, \\.\CON}
    @"CON",

    // {false, nil, C:\Users\User\Documents\PathExplorer\CON\}
    @"CON\",

    // {false, nil, \\.\CON}
    @"CON.TXT",

    // {false, nil, C:\Users\User\Documents\PathExplorer\CON.TXT\}
    @"CON.TXT\",

    // {false, nil, C:\Users\User\Documents\PathExplorer\CON.TXT\FILE.TXT}
    @"CON.TXT\FILE.TXT",

    // {false, nil, \\.\LPT1}
    @"LPT1",

    // {false, nil, C:\Users\User\Documents\PathExplorer\LPT1\}
    @"LPT1\",

    // {false, nil, \\.\LPT1}
    @"LPT1.TXT",

    // {false, nil, C:\Users\User\Documents\PathExplorer\LPT1.TXT\}
    @"LPT1.TXT\",

    // {false, nil, \\.\LPT1}
    @"LPT1.XTX",

    // {false, nil, \\.\COM1}
    @"COM1",

    // {false, nil, C:\Users\User\Documents\PathExplorer\COM1\}
    @"COM1\",

    // {false, nil, \\.\COM1}
    @"COM1.TXT",

    // {false, nil, C:\Users\User\Documents\PathExplorer\COM1.TXT\}
    @"COM1.TXT\",

    // {false, nil, C:\Users\User\Documents\PathExplorer\CON1}
    @"CON1",

    // {false, nil, C:\Users\User\Documents\PathExplorer\LPT1\FILE.TXT}
    @"LPT1\FILE.TXT",

    // {false, nil, C:\Users\User\Documents\PathExplorer\COM}
    @"COM",

    // {false, nil, C:\Users\User\Documents\PathExplorer\COM1.TXT\FILE.TXT}
    @"COM1.TXT\FILE.TXT",

};


static void print(string content) {
    Console.WriteLine(content.TrimEnd());
}

// Print out the path test cases and associated output as source-idempotent code
static void printPathStats(string title, string name, string[] paths) {
    int length = 0;
    int rootLength = 0;
    bool hasRelative = false;
    foreach (string path in paths) {
        length = Math.Max(length, path.Length);
        rootLength = Math.Max(rootLength, path.Length > 0 ? Path.GetPathRoot(path).Length : 0);
        hasRelative = hasRelative || !Path.IsPathFullyQualified(path);
    }

    print($"// {title} test cases:");
    print($"static string[] {name} = {'{'}");
    foreach (string path in paths) {
        bool rooted = Path.IsPathRooted(path);
        string pathRoot = Path.GetPathRoot(path);
        bool fullyQualified = Path.IsPathFullyQualified(path);

        Debug.Assert(rooted == (pathRoot != "" && pathRoot != null));

        string rootStr = rooted ? pathRoot : "nil";

        string qual = fullyQualified ? "true,  " : "false, ";
        string root = $"{rootStr}, {new string(' ', Math.Max(0, rootLength - rootStr.Length))}";
        string full = "<unchanged>";
        if (path != "") {
            string fullPath = Path.GetFullPath(path);
            if (path != fullPath) {
                full = fullPath;
            }
        }

        string prefix = $"    @\"{path}\"";
        string comment = $"    // {{{qual}{root}{full}}}";
        string output = $"{prefix},{new string(' ', length - path.Length)}";

        print(comment);
        print(output);
        print("");
    }
    print("};");
    print("");
}

static void Main(string[] args)
{
    print("// Info: {fullyQualified, root, fullPath}");
    print("");
    printPathStats("Traditional path", "traditionalPaths", traditionalPaths);
    printPathStats("UNC path", "uncPaths", uncPaths);
    printPathStats("DOS device path", "devicePaths", devicePaths);
    printPathStats("DOS device GUID-volume path", "guidPaths", guidPaths);
    printPathStats("Legacy DOS device path", "legacyDevicePaths", legacyDevicePaths);
}

} } // namespace HelloWorld { class Program {