More use of SequenceEqual, IndexOf, IndexOfAnyExcept, etc.

src/coreclr/System.Private.CoreLib/src/System/Reflection/Emit/SignatureHelper.cs

@@ -843,27 +843,13 @@ public void AddSentinel()
             AddElementType(CorElementType.ELEMENT_TYPE_SENTINEL);
         }
 
-        public override bool Equals(object? obj)
-        {
-            if (!(obj is SignatureHelper))
-            {
-                return false;
-            }
-
-            SignatureHelper temp = (SignatureHelper)obj;
-
-            if (!temp.m_module!.Equals(m_module) || temp.m_currSig != m_currSig || temp.m_sizeLoc != m_sizeLoc || temp.m_sigDone != m_sigDone)
-            {
-                return false;
-            }
-
-            for (int i = 0; i < m_currSig; i++)
-            {
-                if (m_signature[i] != temp.m_signature[i])
-                    return false;
-            }
-            return true;
-        }
+        public override bool Equals(object? obj) =>
+            obj is SignatureHelper other &&
+            other.m_module!.Equals(m_module) &&
+            other.m_currSig == m_currSig &&
+            other.m_sizeLoc == m_sizeLoc &&
+            other.m_sigDone == m_sigDone &&
+            m_signature.AsSpan(0, m_currSig).SequenceEqual(other.m_signature.AsSpan(0, m_currSig));
 
         public override int GetHashCode()
         {

src/libraries/Common/src/Interop/Linux/procfs/Interop.ProcFsStat.ParseMapModules.cs

@@ -144,16 +144,8 @@ private static bool TryParseMapsEntry(string line, out (long StartAddress, int S
 
             static bool HasReadAndExecFlags(string s, ref int start, ref int end)
             {
-                bool sawRead = false, sawExec = false;
-                for (int i = start; i < end; i++)
-                {
-                    if (s[i] == 'r')
-                        sawRead = true;
-                    else if (s[i] == 'x')
-                        sawExec = true;
-                }
-
-                return sawRead & sawExec;
+                ReadOnlySpan<char> span = s.AsSpan(start, end - start);
+                return span.Contains('r') && span.Contains('x');
             }
         }
     }

src/libraries/Common/src/Interop/Unix/System.Native/Interop.IPAddress.cs

@@ -73,16 +73,9 @@ public bool Equals(IPAddress other)
 
                 fixed (byte* thisAddress = Address)
                 {
-                    for (int i = 0; i < addressByteCount; i++)
-                    {
-                        if (thisAddress[i] != other.Address[i])
-                        {
-                            return false;
-                        }
-                    }
+                    return new ReadOnlySpan<byte>(thisAddress, addressByteCount).SequenceEqual(
+                           new ReadOnlySpan<byte>(other.Address, addressByteCount));
                 }
-
-                return true;
             }
         }
     }

src/libraries/Microsoft.Extensions.FileProviders.Physical/src/PollingWildCardChangeToken.cs

@@ -158,15 +158,7 @@ private static bool ArrayEquals(byte[]? previousHash, byte[] currentHash)
             }
 
             Debug.Assert(previousHash.Length == currentHash.Length);
-            for (int i = 0; i < previousHash.Length; i++)
-            {
-                if (previousHash[i] != currentHash[i])
-                {
-                    return false;
-                }
-            }
-
-            return true;
+            return previousHash.AsSpan().SequenceEqual(currentHash.AsSpan());
         }
 
         private void ComputeHash(IncrementalHash sha256, string path, DateTime lastChangedUtc)

src/libraries/System.Collections.Concurrent/src/System/Collections/Concurrent/ConcurrentDictionary.cs

@@ -1874,20 +1874,8 @@ void ICollection.CopyTo(Array array, int index)
         #endregion
 
 
-        private bool AreAllBucketsEmpty()
-        {
-            int[] countPerLock = _tables._countPerLock;
-
-            for (int i = 0; i < countPerLock.Length; i++)
-            {
-                if (countPerLock[i] != 0)
-                {
-                    return false;
-                }
-            }
-
-            return true;
-        }
+        private bool AreAllBucketsEmpty() =>
+            _tables._countPerLock.AsSpan().IndexOfAnyExcept(0) < 0;
 
         /// <summary>
         /// Replaces the bucket table with a larger one. To prevent multiple threads from resizing the

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Metrics/StringSequence.cs

@@ -81,36 +81,17 @@ internal partial struct StringSequenceMany : IEquatable<StringSequenceMany>, ISt
     {
         private readonly string[] _values;
 
-        public StringSequenceMany(string[] values)
-        {
+        public StringSequenceMany(string[] values) =>
             _values = values;
-        }
 
-        public Span<string> AsSpan()
-        {
-            return _values.AsSpan();
-        }
+        public Span<string> AsSpan() =>
+            _values.AsSpan();
 
-        public bool Equals(StringSequenceMany other)
-        {
-            if (_values.Length != other._values.Length)
-            {
-                return false;
-            }
-            for (int i = 0; i < _values.Length; i++)
-            {
-                if (_values[i] != other._values[i])
-                {
-                    return false;
-                }
-            }
-            return true;
-        }
+        public bool Equals(StringSequenceMany other) =>
+            _values.AsSpan().SequenceEqual(other._values.AsSpan());
 
         //GetHashCode() is in the platform specific files
-        public override bool Equals(object? obj)
-        {
-            return obj is StringSequenceMany ssm && Equals(ssm);
-        }
+        public override bool Equals(object? obj) =>
+            obj is StringSequenceMany ssm && Equals(ssm);
     }
 }

src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarHelpers.cs

@@ -102,17 +102,8 @@ internal static long ConvertDecimalToOctal(long value)
         }
 
         // Returns true if all the bytes in the specified array are nulls, false otherwise.
-        internal static bool IsAllNullBytes(Span<byte> buffer)
-        {
-            for (int i = 0; i < buffer.Length; i++)
-            {
-                if (buffer[i] != 0)
-                {
-                    return false;
-                }
-            }
-            return true;
-        }
+        internal static bool IsAllNullBytes(Span<byte> buffer) =>
+            buffer.IndexOfAnyExcept((byte)0) < 0;
 
         // Converts the specified number of seconds that have passed since the Unix Epoch to a DateTimeOffset.
         internal static DateTimeOffset GetDateTimeOffsetFromSecondsSinceEpoch(long secondsSinceUnixEpoch) =>

src/libraries/System.Linq.Expressions/src/System/Runtime/CompilerServices/ReadOnlyCollectionBuilder.cs

@@ -220,43 +220,15 @@ public void Clear()
         /// </summary>
         /// <param name="item">the object to locate in the <see cref="ReadOnlyCollectionBuilder{T}"/>.</param>
         /// <returns>true if item is found in the <see cref="ReadOnlyCollectionBuilder{T}"/>; otherwise, false.</returns>
-        public bool Contains(T item)
-        {
-            if ((object?)item == null)
-            {
-                for (int i = 0; i < _size; i++)
-                {
-                    if ((object?)_items[i] == null)
-                    {
-                        return true;
-                    }
-                }
-                return false;
-            }
-            else
-            {
-                EqualityComparer<T> c = EqualityComparer<T>.Default;
-                for (int i = 0; i < _size; i++)
-                {
-                    if (c.Equals(_items[i], item))
-                    {
-                        return true;
-                    }
-                }
-                return false;
-            }
-        }
+        public bool Contains(T item) => IndexOf(item) >= 0;
 
         /// <summary>
         /// Copies the elements of the <see cref="ReadOnlyCollectionBuilder{T}"/> to an <see cref="Array"/>,
         /// starting at particular <see cref="Array"/> index.
         /// </summary>
         /// <param name="array">The one-dimensional <see cref="Array"/> that is the destination of the elements copied from <see cref="ReadOnlyCollectionBuilder{T}"/>.</param>
         /// <param name="arrayIndex">The zero-based index in array at which copying begins.</param>
-        public void CopyTo(T[] array, int arrayIndex)
-        {
-            Array.Copy(_items, 0, array, arrayIndex, _size);
-        }
+        public void CopyTo(T[] array, int arrayIndex) => Array.Copy(_items, 0, array, arrayIndex, _size);
 
         bool ICollection<T>.IsReadOnly => false;
 

src/libraries/System.Net.Http.WinHttpHandler/src/System/Net/Http/WinHttpResponseHeaderReader.cs

@@ -91,30 +91,22 @@ private bool ReadLine(out int startIndex, out int length)
         {
             Debug.Assert(_buffer != null);
 
-            int i = _position;
+            int pos = _position;
 
-            while (i < _length)
+            int newline = _buffer.AsSpan(pos, _length - pos).IndexOf("\r\n".AsSpan());
+            if (newline >= 0)
             {
-                char ch = _buffer[i];
-                if (ch == '\r')
-                {
-                    int next = i + 1;
-                    if (next < _length && _buffer[next] == '\n')
-                    {
-                        startIndex = _position;
-                        length = i - _position;
-                        _position = i + 2;
-                        return true;
-                    }
-                }
-                i++;
+                startIndex = pos;
+                length = newline;
+                _position = pos + newline + 2;
+                return true;
             }
 
-            if (i > _position)
+            if (pos < _length)
             {
-                startIndex = _position;
-                length = i - _position;
-                _position = i;
+                startIndex = pos;
+                length = _length - pos;
+                _position = _length;
                 return true;
             }
 

src/libraries/System.Net.HttpListener/src/System/Net/Windows/HttpListener.Windows.cs

@@ -866,14 +866,8 @@ public HttpListenerContext EndGetContext(IAsyncResult asyncResult)
 
                     // Find the beginning of the blob.  Trust that HTTP.SYS parsed out just our header ok.
                     Debug.Assert(authorizationHeader != null);
-                    for (index++; index < authorizationHeader!.Length; index++)
-                    {
-                        if (authorizationHeader[index] != ' ' && authorizationHeader[index] != '\t' &&
-                            authorizationHeader[index] != '\r' && authorizationHeader[index] != '\n')
-                        {
-                            break;
-                        }
-                    }
+                    int nonWhitespace = authorizationHeader.AsSpan(index + 1).IndexOfAnyExcept(" \t\r\n");
+                    index = nonWhitespace >= 0 ? index + 1 + nonWhitespace : authorizationHeader.Length;
                     string inBlob = index < authorizationHeader.Length ? authorizationHeader.Substring(index) : "";
 
                     IPrincipal? principal = null;

src/libraries/System.Net.NetworkInformation/src/System/Net/NetworkInformation/PhysicalAddress.cs

@@ -57,34 +57,11 @@ public override int GetHashCode()
             return _hash;
         }
 
-        public override bool Equals([NotNullWhen(true)] object? comparand)
-        {
-            PhysicalAddress? address = comparand as PhysicalAddress;
-            if (address == null)
-            {
-                return false;
-            }
-
-            if (_address.Length != address._address.Length)
-            {
-                return false;
-            }
-
-            if (GetHashCode() != address.GetHashCode())
-            {
-                return false;
-            }
-
-            for (int i = 0; i < address._address.Length; i++)
-            {
-                if (_address[i] != address._address[i])
-                {
-                    return false;
-                }
-            }
-
-            return true;
-        }
+        public override bool Equals([NotNullWhen(true)] object? comparand) =>
+            comparand is PhysicalAddress other &&
+            _address.Length == other._address.Length &&
+            GetHashCode() == other.GetHashCode() &&
+            _address.AsSpan().SequenceEqual(other._address);
 
         public override string ToString()
         {

src/libraries/System.Private.CoreLib/src/System/ApplicationId.cs

@@ -68,35 +68,17 @@ public override string ToString()
             return sb.ToString();
         }
 
-        public override bool Equals([NotNullWhen(true)] object? o)
-        {
-            ApplicationId? other = o as ApplicationId;
-            if (other == null)
-                return false;
-
-            if (!(Equals(Name, other.Name) &&
-                  Equals(Version, other.Version) &&
-                  Equals(ProcessorArchitecture, other.ProcessorArchitecture) &&
-                  Equals(Culture, other.Culture)))
-                return false;
-
-            if (_publicKeyToken.Length != other._publicKeyToken.Length)
-                return false;
-
-            for (int i = 0; i < _publicKeyToken.Length; i++)
-            {
-                if (_publicKeyToken[i] != other._publicKeyToken[i])
-                    return false;
-            }
-
-            return true;
-        }
-
-        public override int GetHashCode()
-        {
+        public override bool Equals([NotNullWhen(true)] object? o) =>
+            o is ApplicationId other &&
+            Equals(Name, other.Name) &&
+            Equals(Version, other.Version) &&
+            Equals(ProcessorArchitecture, other.ProcessorArchitecture) &&
+            Equals(Culture, other.Culture) &&
+            _publicKeyToken.AsSpan().SequenceEqual(other._publicKeyToken);
+
+        public override int GetHashCode() =>
             // Note: purposely skipping publicKeyToken, processor architecture and culture as they
             // are less likely to make things not equal than name and version.
-            return Name.GetHashCode() ^ Version.GetHashCode();
-        }
+            Name.GetHashCode() ^ Version.GetHashCode();
     }
 }