Remove Linq from ECDSA and UInt classes

src/neo/Consensus/ConsensusService.cs

@@ -573,7 +573,7 @@ private void OnTimer(Timer timer)
                 {
                     var reason = ChangeViewReason.Timeout;
 
-                    if (context.Block != null && context.TransactionHashes?.Count() > context.Transactions?.Count)
+                    if (context.Block != null && context.TransactionHashes?.Length > context.Transactions?.Count)
                     {
                         reason = ChangeViewReason.TxNotFound;
                     }

src/neo/Cryptography/Base58.cs

@@ -2,6 +2,7 @@
 using System.Linq;
 using System.Numerics;
 using System.Text;
+using static Neo.Helper;
 
 namespace Neo.Cryptography
 {
@@ -27,7 +28,7 @@ public static byte[] Decode(string input)
             var leadingZeros = new byte[leadingZeroCount];
             if (bi.IsZero) return leadingZeros;
             var bytesWithoutLeadingZeros = bi.ToByteArray(isUnsigned: true, isBigEndian: true);
-            return leadingZeros.Concat(bytesWithoutLeadingZeros).ToArray();
+            return Concat(leadingZeros, bytesWithoutLeadingZeros);
         }
 
         public static string Encode(byte[] input)

src/neo/Cryptography/Crypto.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Linq;
 using System.Security.Cryptography;
 
 namespace Neo.Cryptography
@@ -26,8 +25,8 @@ public byte[] Sign(byte[] message, byte[] prikey, byte[] pubkey)
                 D = prikey,
                 Q = new ECPoint
                 {
-                    X = pubkey.Take(32).ToArray(),
-                    Y = pubkey.Skip(32).ToArray()
+                    X = pubkey[..32],
+                    Y = pubkey[32..]
                 }
             }))
             {
@@ -41,7 +40,7 @@ public bool VerifySignature(byte[] message, byte[] signature, byte[] pubkey)
             {
                 try
                 {
-                    pubkey = Cryptography.ECC.ECPoint.DecodePoint(pubkey, Cryptography.ECC.ECCurve.Secp256r1).EncodePoint(false).Skip(1).ToArray();
+                    pubkey = ECC.ECPoint.DecodePoint(pubkey, ECC.ECCurve.Secp256r1).EncodePoint(false)[1..];
                 }
                 catch
                 {
@@ -50,7 +49,7 @@ public bool VerifySignature(byte[] message, byte[] signature, byte[] pubkey)
             }
             else if (pubkey.Length == 65 && pubkey[0] == 0x04)
             {
-                pubkey = pubkey.Skip(1).ToArray();
+                pubkey = pubkey[1..];
             }
             else if (pubkey.Length != 64)
             {
@@ -61,8 +60,8 @@ public bool VerifySignature(byte[] message, byte[] signature, byte[] pubkey)
                 Curve = ECCurve.NamedCurves.nistP256,
                 Q = new ECPoint
                 {
-                    X = pubkey.Take(32).ToArray(),
-                    Y = pubkey.Skip(32).ToArray()
+                    X = pubkey[..32],
+                    Y = pubkey[32..]
                 }
             }))
             {

src/neo/Cryptography/ECC/ECCurve.cs

@@ -12,9 +12,12 @@ public class ECCurve
         public readonly ECPoint Infinity;
         public readonly ECPoint G;
 
+        public readonly int ExpectedECPointLength;
+
         private ECCurve(BigInteger Q, BigInteger A, BigInteger B, BigInteger N, byte[] G)
         {
             this.Q = Q;
+            this.ExpectedECPointLength = (Q.GetBitLength() + 7) / 8;
             this.A = new ECFieldElement(A, this);
             this.B = new ECFieldElement(B, this);
             this.N = N;

src/neo/Cryptography/ECC/ECFieldElement.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Linq;
 using System.Numerics;
 
 namespace Neo.Cryptography.ECC
@@ -28,9 +27,7 @@ public override bool Equals(object obj)
             if (obj == this)
                 return true;
 
-            ECFieldElement other = obj as ECFieldElement;
-
-            if (other == null)
+            if (!(obj is ECFieldElement other))
                 return false;
 
             return Equals(other);
@@ -145,7 +142,9 @@ public byte[] ToByteArray()
             byte[] data = Value.ToByteArray(isUnsigned: true, isBigEndian: true);
             if (data.Length == 32)
                 return data;
-            return Enumerable.Repeat<byte>(0, 32 - data.Length).Concat(data).ToArray();
+            byte[] buffer = new byte[32];
+            Buffer.BlockCopy(data, 0, buffer, buffer.Length - data.Length, data.Length);
+            return buffer;
         }
 
         public static ECFieldElement operator -(ECFieldElement x)

src/neo/Cryptography/ECC/ECPoint.cs

@@ -1,8 +1,8 @@
 using Neo.IO;
 using System;
 using System.IO;
-using System.Linq;
 using System.Numerics;
+using static Neo.Helper;
 
 namespace Neo.Cryptography.ECC
 {
@@ -18,10 +18,7 @@ public bool IsInfinity
 
         public int Size => IsInfinity ? 1 : 33;
 
-        public ECPoint()
-            : this(null, null, ECCurve.Secp256r1)
-        {
-        }
+        public ECPoint() : this(null, null, ECCurve.Secp256r1) { }
 
         internal ECPoint(ECFieldElement x, ECFieldElement y, ECCurve curve)
         {
@@ -43,13 +40,12 @@ public int CompareTo(ECPoint other)
         public static ECPoint DecodePoint(byte[] encoded, ECCurve curve)
         {
             ECPoint p = null;
-            int expectedLength = (curve.Q.GetBitLength() + 7) / 8;
             switch (encoded[0])
             {
                 case 0x02: // compressed
                 case 0x03: // compressed
                     {
-                        if (encoded.Length != (expectedLength + 1))
+                        if (encoded.Length != (curve.ExpectedECPointLength + 1))
                             throw new FormatException("Incorrect length for compressed encoding");
                         int yTilde = encoded[0] & 1;
                         BigInteger X1 = new BigInteger(encoded.AsSpan(1), isUnsigned: true, isBigEndian: true);
@@ -58,10 +54,10 @@ public static ECPoint DecodePoint(byte[] encoded, ECCurve curve)
                     }
                 case 0x04: // uncompressed
                     {
-                        if (encoded.Length != (2 * expectedLength + 1))
+                        if (encoded.Length != (2 * curve.ExpectedECPointLength + 1))
                             throw new FormatException("Incorrect length for uncompressed/hybrid encoding");
-                        BigInteger X1 = new BigInteger(encoded.AsSpan(1, expectedLength), isUnsigned: true, isBigEndian: true);
-                        BigInteger Y1 = new BigInteger(encoded.AsSpan(1 + expectedLength), isUnsigned: true, isBigEndian: true);
+                        BigInteger X1 = new BigInteger(encoded.AsSpan(1, curve.ExpectedECPointLength), isUnsigned: true, isBigEndian: true);
+                        BigInteger Y1 = new BigInteger(encoded.AsSpan(1 + curve.ExpectedECPointLength), isUnsigned: true, isBigEndian: true);
                         p = new ECPoint(new ECFieldElement(X1, curve), new ECFieldElement(Y1, curve), curve);
                         break;
                     }
@@ -105,23 +101,22 @@ void ISerializable.Deserialize(BinaryReader reader)
 
         public static ECPoint DeserializeFrom(BinaryReader reader, ECCurve curve)
         {
-            int expectedLength = (curve.Q.GetBitLength() + 7) / 8;
-            byte[] buffer = new byte[1 + expectedLength * 2];
+            byte[] buffer = new byte[1 + curve.ExpectedECPointLength * 2];
             buffer[0] = reader.ReadByte();
             switch (buffer[0])
             {
                 case 0x02:
                 case 0x03:
                     {
-                        if (reader.Read(buffer, 1, expectedLength) != expectedLength)
+                        if (reader.Read(buffer, 1, curve.ExpectedECPointLength) != curve.ExpectedECPointLength)
                         {
                             throw new FormatException();
                         }
-                        return DecodePoint(buffer.Take(1 + expectedLength).ToArray(), curve);
+                        return DecodePoint(buffer[..(1 + curve.ExpectedECPointLength)], curve);
                     }
                 case 0x04:
                     {
-                        if (reader.Read(buffer, 1, expectedLength * 2) != expectedLength * 2)
+                        if (reader.Read(buffer, 1, curve.ExpectedECPointLength * 2) != curve.ExpectedECPointLength * 2)
                         {
                             throw new FormatException();
                         }
@@ -175,10 +170,10 @@ public static ECPoint FromBytes(byte[] pubkey, ECCurve curve)
                     return DecodePoint(pubkey, curve);
                 case 64:
                 case 72:
-                    return DecodePoint(new byte[] { 0x04 }.Concat(pubkey.Skip(pubkey.Length - 64)).ToArray(), curve);
+                    return DecodePoint(Concat(new byte[] { 0x04 }, pubkey[^64..]), curve);
                 case 96:
                 case 104:
-                    return DecodePoint(new byte[] { 0x04 }.Concat(pubkey.Skip(pubkey.Length - 96).Take(64)).ToArray(), curve);
+                    return DecodePoint(Concat(new byte[] { 0x04 }, pubkey[^96..^32]), curve);
                 default:
                     throw new FormatException();
             }
@@ -241,7 +236,7 @@ internal static ECPoint Multiply(ECPoint p, BigInteger k)
             // The length of the precomputation array
             int preCompLen = 1;
 
-            ECPoint[] preComp = preComp = new ECPoint[] { p };
+            ECPoint[] preComp = new ECPoint[] { p };
             ECPoint twiceP = p.Twice();
 
             if (preCompLen < reqPreCompLen)

src/neo/Cryptography/Helper.cs

@@ -77,9 +77,9 @@ public static byte[] Base58CheckDecode(this string input)
             byte[] buffer = Base58.Decode(input);
             if (buffer.Length < 4) throw new FormatException();
             byte[] checksum = buffer.Sha256(0, buffer.Length - 4).Sha256();
-            if (!buffer.Skip(buffer.Length - 4).SequenceEqual(checksum.Take(4)))
+            if (!buffer.AsSpan(^4).SequenceEqual(checksum.AsSpan(..4)))
                 throw new FormatException();
-            var ret = buffer.Take(buffer.Length - 4).ToArray();
+            var ret = buffer[..^4];
             Array.Clear(buffer, 0, buffer.Length);
             return ret;
         }

src/neo/Helper.cs

@@ -17,6 +17,7 @@ public static class Helper
     {
         private static readonly DateTime unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static int BitLen(int w)
         {
             return (w < 1 << 15 ? (w < 1 << 7
@@ -34,6 +35,20 @@ private static int BitLen(int w)
                 : (w < 1 << 29 ? (w < 1 << 28 ? 28 : 29) : (w < 1 << 30 ? 30 : 31)))));
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static byte[] Concat(params byte[][] buffers)
+        {
+            var ret = new byte[buffers.Sum(p => p.Length)];
+            int i = 0;
+            foreach (byte[] buffer in buffers)
+            {
+                Buffer.BlockCopy(buffer, 0, ret, i, buffer.Length);
+                i += buffer.Length;
+            }
+            return ret;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal static int GetBitLength(this BigInteger i)
         {
             byte[] b = i.ToByteArray();
@@ -110,6 +125,7 @@ public static byte[] HexToBytes(this string value)
             return result;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal static BigInteger Mod(this BigInteger x, BigInteger y)
         {
             x %= y;
@@ -172,20 +188,28 @@ public static BigInteger Sum(this IEnumerable<BigInteger> source)
             return sum;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal static bool TestBit(this BigInteger i, int index)
         {
             return (i & (BigInteger.One << index)) > BigInteger.Zero;
         }
 
-
-        public static string ToHexString(this IEnumerable<byte> value)
+        public static string ToHexString(this byte[] value)
         {
             StringBuilder sb = new StringBuilder();
             foreach (byte b in value)
                 sb.AppendFormat("{0:x2}", b);
             return sb.ToString();
         }
 
+        public static string ToHexString(this byte[] value, bool reverse = false)
+        {
+            StringBuilder sb = new StringBuilder();
+            for (int i = 0; i < value.Length; i++)
+                sb.AppendFormat("{0:x2}", value[reverse ? value.Length - i - 1 : i]);
+            return sb.ToString();
+        }
+
         public static string ToHexString(this ReadOnlySpan<byte> value)
         {
             StringBuilder sb = new StringBuilder();

src/neo/IO/Caching/DataCache.cs

@@ -129,7 +129,7 @@ public void DeleteWhere(Func<TKey, TValue, bool> predicate)
             lock (dictionary)
             {
                 cached = dictionary
-                    .Where(p => p.Value.State != TrackState.Deleted && (key_prefix == null || p.Key.ToArray().Take(key_prefix.Length).SequenceEqual(key_prefix)))
+                    .Where(p => p.Value.State != TrackState.Deleted && (key_prefix == null || p.Key.ToArray().AsSpan().StartsWith(key_prefix)))
                     .Select(p =>
                     (
                         KeyBytes: p.Key.ToArray(),

src/neo/IO/Data/LevelDB/Helper.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 
 namespace Neo.IO.Data.LevelDB
 {
@@ -26,7 +25,7 @@ public static IEnumerable<T> Find<T>(this DB db, ReadOptions options, Slice pref
                     byte[] x = key.ToArray();
                     byte[] y = prefix.ToArray();
                     if (x.Length < y.Length) break;
-                    if (!x.Take(y.Length).SequenceEqual(y)) break;
+                    if (!x.AsSpan().StartsWith(y)) break;
                     yield return resultSelector(key, it.Value());
                 }
             }

src/neo/IO/Data/LevelDB/Slice.cs

@@ -1,6 +1,5 @@
 using Neo.Cryptography;
 using System;
-using System.Linq;
 using System.Runtime.InteropServices;
 using System.Text;
 
@@ -29,7 +28,7 @@ public int CompareTo(Slice other)
         public bool Equals(Slice other)
         {
             if (buffer.Length != other.buffer.Length) return false;
-            return buffer.SequenceEqual(other.buffer);
+            return MemoryExtensions.SequenceEqual<byte>(buffer, other.buffer);
         }
 
         public override bool Equals(object obj)

src/neo/Ledger/StorageKey.cs

@@ -2,7 +2,6 @@
 using Neo.IO;
 using System;
 using System.IO;
-using System.Linq;
 
 namespace Neo.Ledger
 {
@@ -28,7 +27,7 @@ internal static byte[] CreateSearchPrefix(UInt160 hash, byte[] prefix)
                 }
                 if (remain > 0)
                     ms.Write(prefix, index, remain);
-                return hash.ToArray().Concat(ms.ToArray()).ToArray();
+                return Helper.Concat(hash.ToArray(), ms.ToArray());
             }
         }
 
@@ -44,7 +43,7 @@ public bool Equals(StorageKey other)
                 return false;
             if (ReferenceEquals(this, other))
                 return true;
-            return ScriptHash.Equals(other.ScriptHash) && Key.SequenceEqual(other.Key);
+            return ScriptHash.Equals(other.ScriptHash) && MemoryExtensions.SequenceEqual<byte>(Key, other.Key);
         }
 
         public override bool Equals(object obj)

src/neo/Network/P2P/Payloads/Block.cs

@@ -3,7 +3,6 @@
 using Neo.IO.Json;
 using Neo.Ledger;
 using Neo.SmartContract;
-using Neo.VM;
 using Neo.VM.Types;
 using System;
 using System.Collections.Generic;
@@ -130,7 +129,7 @@ public TrimmedBlock Trim()
                 Index = Index,
                 NextConsensus = NextConsensus,
                 Witness = Witness,
-                Hashes = new[] { ConsensusData.Hash }.Concat(Transactions.Select(p => p.Hash)).ToArray(),
+                Hashes = Transactions.Select(p => p.Hash).Prepend(ConsensusData.Hash).ToArray(),
                 ConsensusData = ConsensusData
             };
         }

src/neo/Network/P2P/Payloads/InvPayload.cs

@@ -2,7 +2,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 
 namespace Neo.Network.P2P.Payloads
 {
@@ -30,7 +29,7 @@ public static IEnumerable<InvPayload> CreateGroup(InventoryType type, UInt256[]
                 yield return new InvPayload
                 {
                     Type = type,
-                    Hashes = hashes.Skip(i).Take(MaxHashesCount).ToArray()
+                    Hashes = hashes[i..(i + MaxHashesCount)]
                 };
         }