Add MemoryExtensions.Split

src/libraries/Common/src/Interop/Linux/cgroups/Interop.cgroups.cs

@@ -316,12 +316,12 @@ internal static bool TryFindCGroupPathForSubsystem(CGroupVersion cgroupVersion,
                 {
                     using (var reader = new StreamReader(procCGroupFilePath))
                     {
+                        Span<Range> lineParts = stackalloc Range[4];
                         string? line;
                         while ((line = reader.ReadLine()) != null)
                         {
-                            string[] lineParts = line.Split(':');
-
-                            if (lineParts.Length != 3)
+                            ReadOnlySpan<char> lineSpan = line;
+                            if (lineSpan.Split(lineParts, ':') != 3)
                             {
                                 // Malformed line.
                                 continue;
@@ -333,23 +333,23 @@ internal static bool TryFindCGroupPathForSubsystem(CGroupVersion cgroupVersion,
                                 // list. See man page for cgroups for /proc/[pid]/cgroups format, e.g:
                                 //     hierarchy-ID:controller-list:cgroup-path
                                 //     5:cpuacct,cpu,cpuset:/daemons
-                                if (Array.IndexOf(lineParts[1].Split(','), subsystem) < 0)
+                                if (Array.IndexOf(line[lineParts[1]].Split(','), subsystem) < 0)
                                 {
                                     // Not the relevant entry.
                                     continue;
                                 }
 
-                                path = lineParts[2];
+                                path = line[lineParts[2]];
                                 return true;
                             }
                             else if (cgroupVersion == CGroupVersion.CGroup2)
                             {
                                 // cgroup v2: Find the first entry that matches the cgroup v2 hierarchy:
                                 //     0::$PATH
 
-                                if ((lineParts[0] == "0") && (lineParts[1].Length == 0))
+                                if (lineSpan[lineParts[0]] is "0" && lineSpan[lineParts[1]].IsEmpty)
                                 {
-                                    path = lineParts[2];
+                                    path = line[lineParts[2]];
                                     return true;
                                 }
                             }

src/libraries/Common/src/System/Drawing/ColorConverterCommon.cs

@@ -53,27 +53,17 @@ public static Color ConvertFromString(string strValue, CultureInfo culture)
                 }
             }
 
-            // Nope. Parse the RGBA from the text.
-            //
-            string[] tokens = text.Split(sep);
-            int[] values = new int[tokens.Length];
-            for (int i = 0; i < values.Length; i++)
-            {
-                values[i] = unchecked(IntFromString(tokens[i], culture));
-            }
-
-            // We should now have a number of parsed integer values.
             // We support 1, 3, or 4 arguments:
-            //
             // 1 -- full ARGB encoded
             // 3 -- RGB
             // 4 -- ARGB
-            //
-            return values.Length switch
+            ReadOnlySpan<char> textSpan = text;
+            Span<Range> tokens = stackalloc Range[5];
+            return textSpan.Split(tokens, sep) switch
             {
-                1 => PossibleKnownColor(Color.FromArgb(values[0])),
-                3 => PossibleKnownColor(Color.FromArgb(values[0], values[1], values[2])),
-                4 => PossibleKnownColor(Color.FromArgb(values[0], values[1], values[2], values[3])),
+                1 => PossibleKnownColor(Color.FromArgb(IntFromString(textSpan[tokens[0]], culture))),
+                3 => PossibleKnownColor(Color.FromArgb(IntFromString(textSpan[tokens[0]], culture), IntFromString(textSpan[tokens[1]], culture), IntFromString(textSpan[tokens[2]], culture))),
+                4 => PossibleKnownColor(Color.FromArgb(IntFromString(textSpan[tokens[0]], culture), IntFromString(textSpan[tokens[1]], culture), IntFromString(textSpan[tokens[2]], culture), IntFromString(textSpan[tokens[3]], culture))),
                 _ => throw new ArgumentException(SR.Format(SR.InvalidColor, text)),
             };
         }
@@ -96,42 +86,31 @@ private static Color PossibleKnownColor(Color color)
             return color;
         }
 
-        private static int IntFromString(string text, CultureInfo culture)
+        private static int IntFromString(ReadOnlySpan<char> text, CultureInfo culture)
         {
             text = text.Trim();
 
             try
             {
                 if (text[0] == '#')
                 {
-                    return IntFromString(text.Substring(1), 16);
+                    return Convert.ToInt32(text.Slice(1).ToString(), 16);
                 }
-                else if (text.StartsWith("0x", StringComparison.OrdinalIgnoreCase)
-                         || text.StartsWith("&h", StringComparison.OrdinalIgnoreCase))
+                else if (text.StartsWith("0x", StringComparison.OrdinalIgnoreCase) || text.StartsWith("&h", StringComparison.OrdinalIgnoreCase))
                 {
-                    return IntFromString(text.Substring(2), 16);
+                    return Convert.ToInt32(text.Slice(2).ToString(), 16);
                 }
                 else
                 {
                     Debug.Assert(culture != null);
                     var formatInfo = (NumberFormatInfo?)culture.GetFormat(typeof(NumberFormatInfo));
-                    return IntFromString(text, formatInfo);
+                    return int.Parse(text, provider: formatInfo);
                 }
             }
             catch (Exception e)
             {
-                throw new ArgumentException(SR.Format(SR.ConvertInvalidPrimitive, text, nameof(Int32)), e);
+                throw new ArgumentException(SR.Format(SR.ConvertInvalidPrimitive, text.ToString(), nameof(Int32)), e);
             }
         }
-
-        private static int IntFromString(string value, int radix)
-        {
-            return Convert.ToInt32(value, radix);
-        }
-
-        private static int IntFromString(string value, NumberFormatInfo? formatInfo)
-        {
-            return int.Parse(value, NumberStyles.Integer, formatInfo);
-        }
     }
 }

src/libraries/System.Data.Common/src/System/Data/XDRSchema.cs

@@ -297,16 +297,17 @@ private static NameType FindNameType(string name)
         private static Type ParseDataType(string dt, string dtValues)
         {
             string strType = dt;
-            string[] parts = dt.Split(':');
 
-            if (parts.Length > 2)
+            Span<System.Range> parts = stackalloc System.Range[3];
+            switch (dt.AsSpan().Split(parts, ':'))
             {
-                throw ExceptionBuilder.InvalidAttributeValue("type", dt);
-            }
-            else if (parts.Length == 2)
-            {
-                // CONSIDER: check that we have valid prefix
-                strType = parts[1];
+                case 2:
+                    // CONSIDER: check that we have valid prefix
+                    strType = dt[parts[1]];
+                    break;
+
+                case > 2:
+                    throw ExceptionBuilder.InvalidAttributeValue("type", dt);
             }
 
             NameType nt = FindNameType(strType);

src/libraries/System.Diagnostics.FileVersionInfo/src/System/Diagnostics/FileVersionInfo.Unix.cs

@@ -199,22 +199,23 @@ private static void ParseVersion(string? versionString, out int major, out int m
 
             major = minor = build = priv = 0;
 
-            if (versionString != null)
+            ReadOnlySpan<char> versionSpan = versionString;
+
+            Span<Range> parts = stackalloc Range[5];
+            parts = parts.Slice(0, versionSpan.Split(parts, '.'));
+
+            if (parts.Length <= 4 && parts.Length > 0)
             {
-                string[] parts = versionString.Split('.');
-                if (parts.Length <= 4 && parts.Length > 0)
+                major = ParseUInt16UntilNonDigit(versionSpan[parts[0]], out bool endedEarly);
+                if (!endedEarly && parts.Length > 1)
                 {
-                    major = ParseUInt16UntilNonDigit(parts[0], out bool endedEarly);
-                    if (!endedEarly && parts.Length > 1)
+                    minor = ParseUInt16UntilNonDigit(versionSpan[parts[1]], out endedEarly);
+                    if (!endedEarly && parts.Length > 2)
                     {
-                        minor = ParseUInt16UntilNonDigit(parts[1], out endedEarly);
-                        if (!endedEarly && parts.Length > 2)
+                        build = ParseUInt16UntilNonDigit(versionSpan[parts[2]], out endedEarly);
+                        if (!endedEarly && parts.Length > 3)
                         {
-                            build = ParseUInt16UntilNonDigit(parts[2], out endedEarly);
-                            if (!endedEarly && parts.Length > 3)
-                            {
-                                priv = ParseUInt16UntilNonDigit(parts[3], out _);
-                            }
+                            priv = ParseUInt16UntilNonDigit(versionSpan[parts[3]], out _);
                         }
                     }
                 }
@@ -225,7 +226,7 @@ private static void ParseVersion(string? versionString, out int major, out int m
         /// <param name="s">The string to parse.</param>
         /// <param name="endedEarly">Whether parsing ended prior to reaching the end of the input.</param>
         /// <returns>The parsed value.</returns>
-        private static ushort ParseUInt16UntilNonDigit(string s, out bool endedEarly)
+        private static ushort ParseUInt16UntilNonDigit(ReadOnlySpan<char> s, out bool endedEarly)
         {
             endedEarly = false;
             ushort result = 0;

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Windows.cs

@@ -191,7 +191,7 @@ private static bool IsRemoteMachineCore(string machineName)
         {
             ReadOnlySpan<char> baseName = machineName.AsSpan(machineName.StartsWith('\\') ? 2 : 0);
             return
-                !baseName.Equals(".", StringComparison.Ordinal) &&
+                baseName is not "." &&
                 !baseName.Equals(Interop.Kernel32.GetComputerName(), StringComparison.OrdinalIgnoreCase);
         }
 
@@ -499,7 +499,7 @@ private static ProcessInfo[] GetProcessInfos(PerformanceCounterLib library, int
 
                     ReadOnlySpan<char> instanceName = PERF_INSTANCE_DEFINITION.GetName(in instance, data.Slice(instancePos));
 
-                    if (instanceName.Equals("_Total", StringComparison.Ordinal))
+                    if (instanceName is "_Total")
                     {
                         // continue
                     }

src/libraries/System.Drawing.Primitives/src/System.Drawing.Primitives.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <RootNamespace>System.Drawing</RootNamespace>
     <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent)</TargetFrameworks>
@@ -37,6 +37,7 @@
   <ItemGroup>
     <Reference Include="System.Collections" />
     <Reference Include="System.ComponentModel.Primitives" />
+    <Reference Include="System.Memory" />
     <Reference Include="System.Numerics.Vectors" />
     <Reference Include="System.ObjectModel" />
     <Reference Include="System.Runtime" />

src/libraries/System.Memory/ref/System.Memory.cs

@@ -315,6 +315,10 @@ public static void Sort<TKey, TValue>(this System.Span<TKey> keys, System.Span<T
         public static void Sort<TKey, TValue>(this System.Span<TKey> keys, System.Span<TValue> items, System.Comparison<TKey> comparison) { }
         public static void Sort<T, TComparer>(this System.Span<T> span, TComparer comparer) where TComparer : System.Collections.Generic.IComparer<T>? { }
         public static void Sort<TKey, TValue, TComparer>(this System.Span<TKey> keys, System.Span<TValue> items, TComparer comparer) where TComparer : System.Collections.Generic.IComparer<TKey>? { }
+        public static int Split(this System.ReadOnlySpan<char> source, System.Span<System.Range> destination, char separator, System.StringSplitOptions options = System.StringSplitOptions.None) { throw null; }
+        public static int Split(this System.ReadOnlySpan<char> source, System.Span<System.Range> destination, System.ReadOnlySpan<char> separator, System.StringSplitOptions options = System.StringSplitOptions.None) { throw null; }
+        public static int SplitAny(this System.ReadOnlySpan<char> source, System.Span<System.Range> destination, System.ReadOnlySpan<char> separators, System.StringSplitOptions options = System.StringSplitOptions.None) { throw null; }
+        public static int SplitAny(this System.ReadOnlySpan<char> source, System.Span<System.Range> destination, System.ReadOnlySpan<string> separators, System.StringSplitOptions options = System.StringSplitOptions.None) { throw null; }
         public static bool StartsWith(this System.ReadOnlySpan<char> span, System.ReadOnlySpan<char> value, System.StringComparison comparisonType) { throw null; }
         public static bool StartsWith<T>(this System.ReadOnlySpan<T> span, System.ReadOnlySpan<T> value) where T : System.IEquatable<T>? { throw null; }
         public static bool StartsWith<T>(this System.Span<T> span, System.ReadOnlySpan<T> value) where T : System.IEquatable<T>? { throw null; }

src/libraries/System.Net.Http/src/System/Net/Http/Headers/AltSvcHeaderParser.cs

@@ -226,7 +226,7 @@ private static bool TryReadPercentEncodedAlpnProtocolName(string value, int star
                     }
                     break;
                 case 5:
-                    if (span.SequenceEqual("clear"))
+                    if (span is "clear")
                     {
                         result = "clear";
                         return true;

src/libraries/System.Net.Http/src/System/Net/Http/Headers/ContentDispositionHeaderValue.cs

@@ -470,9 +470,13 @@ private static bool TryDecodeMime(string? input, [NotNullWhen(true)] out string?
                 return false;
             }
 
-            string[] parts = processedInput.Split('?');
+            Span<Range> parts = stackalloc Range[6];
+            ReadOnlySpan<char> processedInputSpan = processedInput;
             // "=, encodingName, encodingType, encodedData, ="
-            if (parts.Length != 5 || parts[0] != "\"=" || parts[4] != "=\"" || parts[2].ToLowerInvariant() != "b")
+            if (processedInputSpan.Split(parts, '?') != 5 ||
+                processedInputSpan[parts[0]] is not "\"=" ||
+                processedInputSpan[parts[4]] is not "=\"" ||
+                !processedInputSpan[parts[2]].Equals("b", StringComparison.OrdinalIgnoreCase))
             {
                 // Not encoded.
                 // This does not support multi-line encoding.
@@ -482,8 +486,8 @@ private static bool TryDecodeMime(string? input, [NotNullWhen(true)] out string?
 
             try
             {
-                Encoding encoding = Encoding.GetEncoding(parts[1]);
-                byte[] bytes = Convert.FromBase64String(parts[3]);
+                Encoding encoding = Encoding.GetEncoding(processedInput[parts[1]]);
+                byte[] bytes = Convert.FromBase64String(processedInput[parts[3]]);
                 output = encoding.GetString(bytes, 0, bytes.Length);
                 return true;
             }

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpEnvironmentProxy.cs

@@ -234,10 +234,11 @@ private HttpEnvironmentProxy(Uri? httpProxy, Uri? httpsProxy, string? bypassList
                 // UriBuilder does not handle that now e.g. does not distinguish between empty and missing.
                 if (user == "" && password == "")
                 {
-                    string[] tokens = uri.ToString().Split('/', 3);
-                    if (tokens.Length == 3)
+                    Span<Range> tokens = stackalloc Range[3];
+                    ReadOnlySpan<char> uriSpan = uri.ToString();
+                    if (uriSpan.Split(tokens, '/') == 3)
                     {
-                        uri = new Uri($"{tokens[0]}//:@{tokens[2]}");
+                        uri = new Uri($"{uriSpan[tokens[0]]}//:@{uriSpan[tokens[2]]}");
                     }
                 }
 

src/libraries/System.Net.Primitives/src/System/Net/CookieContainer.cs

@@ -614,13 +614,15 @@ internal bool IsLocalDomain(string host)
             }
 
             // Test for "127.###.###.###" without using regex.
-            string[] ipParts = host.Split('.');
-            if (ipParts != null && ipParts.Length == 4 && ipParts[0] == "127")
+            ReadOnlySpan<char> hostSpan = host;
+            Span<Range> ipParts = stackalloc Range[5];
+            ipParts = ipParts.Slice(0, hostSpan.Split(ipParts, '.'));
+            if (ipParts.Length == 4 && hostSpan[ipParts[0]] is "127")
             {
                 int i;
                 for (i = 1; i < ipParts.Length; i++)
                 {
-                    string part = ipParts[i];
+                    ReadOnlySpan<char> part = hostSpan[ipParts[i]];
                     switch (part.Length)
                     {
                         case 3:

src/libraries/System.Private.CoreLib/src/System/Globalization/CultureInfo.cs

@@ -505,7 +505,7 @@ public virtual CultureInfo Parent
                                 parentName = "zh-Hant";
                             }
                         }
-                        else if (_name.Length > 8 && _name.AsSpan(2, 4).Equals("-Han", StringComparison.Ordinal) && _name[7] == '-') // cultures like zh-Hant-* and zh-Hans-*
+                        else if (_name.Length > 8 && _name.AsSpan(2, 4) is "-Han" && _name[7] == '-') // cultures like zh-Hant-* and zh-Hans-*
                         {
                             if (_name[6] == 't') // zh-Hant-*
                             {

src/libraries/System.Private.CoreLib/src/System/Globalization/JapaneseCalendar.Nls.cs

@@ -184,29 +184,32 @@ private static int CompareEraRanges(EraInfo a, EraInfo b)
             // Get Strings
             //
             // Needs to be a certain length e_a_E_A at least (7 chars, exactly 4 groups)
-            string[] names = data.Split('_');
-
             // Should have exactly 4 parts
             // 0 - Era Name
             // 1 - Abbreviated Era Name
             // 2 - English Era Name
             // 3 - Abbreviated English Era Name
-            if (names.Length != 4) return null;
+            Span<Range> names = stackalloc Range[5];
+            ReadOnlySpan<char> dataSpan = data;
+            if (dataSpan.Split(names, '_') == 4)
+            {
+                ReadOnlySpan<char> eraName = dataSpan[names[0]];
+                ReadOnlySpan<char> abbreviatedEraName = dataSpan[names[1]];
+                ReadOnlySpan<char> englishEraName = dataSpan[names[2]];
+                ReadOnlySpan<char> abbreviatedEnglishEraName = dataSpan[names[3]];
 
-            // Each part should have data in it
-            if (names[0].Length == 0 ||
-                names[1].Length == 0 ||
-                names[2].Length == 0 ||
-                names[3].Length == 0)
-                return null;
+                // Each part should have data in it
+                if (!eraName.IsEmpty && !abbreviatedEraName.IsEmpty && !englishEraName.IsEmpty && !abbreviatedEnglishEraName.IsEmpty)
+                {
+                    // Now we have an era we can build
+                    // Note that the era # and max era year need cleaned up after sorting
+                    // Don't use the full English Era Name (names[2])
+                    return new EraInfo(0, year, month, day, year - 1, 1, 0,
+                                       eraName.ToString(), abbreviatedEraName.ToString(), abbreviatedEnglishEraName.ToString());
+                }
+            }
 
-            //
-            // Now we have an era we can build
-            // Note that the era # and max era year need cleaned up after sorting
-            // Don't use the full English Era Name (names[2])
-            //
-            return new EraInfo(0, year, month, day, year - 1, 1, 0,
-                                names[0], names[1], names[3]);
+            return null;
         }
     }
 }