Merge pull request #531 from carbon/master

Improve CQ3

src/SharpCompress/Common/GZip/GZipFilePart.cs

@@ -8,7 +8,7 @@
 
 namespace SharpCompress.Common.GZip
 {
-    internal class GZipFilePart : FilePart
+    internal sealed class GZipFilePart : FilePart
     {
         private string? _name;
         private readonly Stream _stream;
@@ -40,8 +40,8 @@ internal override Stream GetRawStream()
         private void ReadAndValidateGzipHeader(Stream stream)
         {
             // read the header on the first read
-            byte[] header = new byte[10];
-            int n = stream.Read(header, 0, header.Length);
+            Span<byte> header = stackalloc byte[10];
+            int n = stream.Read(header);
 
             // workitem 8501: handle edge case (decompress empty stream)
             if (n == 0)
@@ -59,14 +59,14 @@ private void ReadAndValidateGzipHeader(Stream stream)
                 throw new ZlibException("Bad GZIP header.");
             }
 
-            int timet = BinaryPrimitives.ReadInt32LittleEndian(header.AsSpan(4));
+            int timet = BinaryPrimitives.ReadInt32LittleEndian(header.Slice(4));
             DateModified = TarHeader.EPOCH.AddSeconds(timet);
             if ((header[3] & 0x04) == 0x04)
             {
                 // read and discard extra field
-                n = stream.Read(header, 0, 2); // 2-byte length field
+                n = stream.Read(header.Slice(0, 2)); // 2-byte length field
 
-                Int16 extraLength = (Int16)(header[0] + header[1] * 256);
+                short extraLength = (short)(header[0] + header[1] * 256);
                 byte[] extra = new byte[extraLength];
 
                 if (!stream.ReadFully(extra))

src/SharpCompress/Common/Rar/RarRijndael.cs

@@ -87,11 +87,11 @@ public static RarRijndael InitializeFrom(string password, byte[] salt)
             return rijndael;
         }
 
-        public byte[] ProcessBlock(byte[] cipherText)
+        public byte[] ProcessBlock(ReadOnlySpan<byte> cipherText)
         {
-            var plainText = new byte[CRYPTO_BLOCK_SIZE];
+            Span<byte> plainText = stackalloc byte[CRYPTO_BLOCK_SIZE]; // 16 bytes
             byte[] decryptedBytes = new byte[CRYPTO_BLOCK_SIZE];
-            _rijndael.ProcessBlock(cipherText, 0, plainText, 0);
+            _rijndael.ProcessBlock(cipherText, plainText);
 
             for (int j = 0; j < CRYPTO_BLOCK_SIZE; j++)
             {

src/SharpCompress/Common/SevenZip/CMethodId.cs

@@ -1,6 +1,6 @@
 namespace SharpCompress.Common.SevenZip
 {
-    internal struct CMethodId
+    internal readonly struct CMethodId
     {
         public const ulong K_COPY_ID = 0;
         public const ulong K_LZMA_ID = 0x030101;
@@ -26,7 +26,7 @@ public override int GetHashCode()
 
         public override bool Equals(object obj)
         {
-            return obj is CMethodId && (CMethodId)obj == this;
+            return obj is CMethodId other && Equals(other);
         }
 
         public bool Equals(CMethodId other)

src/SharpCompress/Common/Tar/Headers/TarHeader.cs

@@ -7,7 +7,7 @@
 
 namespace SharpCompress.Common.Tar.Headers
 {
-    internal class TarHeader
+    internal sealed class TarHeader
     {
         internal static readonly DateTime EPOCH = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
 
@@ -260,10 +260,16 @@ private static long ReadAsciiInt64(byte[] buffer, int offset, int count)
             return Convert.ToInt64(s);
         }
 
+
+        private static readonly byte[] eightSpaces = { 
+            (byte)' ', (byte)' ', (byte)' ', (byte)' ',
+            (byte)' ', (byte)' ', (byte)' ', (byte)' ' 
+        };
+
         internal static int RecalculateChecksum(byte[] buf)
         {
             // Set default value for checksum. That is 8 spaces.
-            Encoding.UTF8.GetBytes("        ").CopyTo(buf, 148);
+            eightSpaces.CopyTo(buf, 148);
 
             // Calculate checksum
             int headerChecksum = 0;
@@ -276,7 +282,7 @@ internal static int RecalculateChecksum(byte[] buf)
 
         internal static int RecalculateAltChecksum(byte[] buf)
         {
-            Encoding.UTF8.GetBytes("        ").CopyTo(buf, 148);
+            eightSpaces.CopyTo(buf, 148);
             int headerChecksum = 0;
             foreach (byte b in buf)
             {

src/SharpCompress/Compressors/ADC/ADCBase.cs

@@ -52,32 +52,24 @@ private static int GetChunkType(byte byt)
 
         private static int GetChunkSize(byte byt)
         {
-            switch (GetChunkType(byt))
+            return GetChunkType(byt) switch
             {
-                case PLAIN:
-                    return (byt & 0x7F) + 1;
-                case TWO_BYTE:
-                    return ((byt & 0x3F) >> 2) + 3;
-                case THREE_BYTE:
-                    return (byt & 0x3F) + 4;
-                default:
-                    return -1;
-            }
+                PLAIN => (byt & 0x7F) + 1,
+                TWO_BYTE => ((byt & 0x3F) >> 2) + 3,
+                THREE_BYTE => (byt & 0x3F) + 4,
+                _ => -1,
+            };
         }
 
         private static int GetOffset(ReadOnlySpan<byte> chunk)
         {
-            switch (GetChunkType(chunk[0]))
+            return GetChunkType(chunk[0]) switch
             {
-                case PLAIN:
-                    return 0;
-                case TWO_BYTE:
-                    return ((chunk[0] & 0x03) << 8) + chunk[1];
-                case THREE_BYTE:
-                    return (chunk[1] << 8) + chunk[2];
-                default:
-                    return -1;
-            }
+                PLAIN => 0,
+                TWO_BYTE => ((chunk[0] & 0x03) << 8) + chunk[1],
+                THREE_BYTE => (chunk[1] << 8) + chunk[2],
+                _ => -1,
+            };
         }
 
         /// <summary>

src/SharpCompress/Compressors/BZip2/CBZip2InputStream.cs

@@ -1,5 +1,6 @@
 #nullable disable
 
+using System;
 using System.IO;
 
 /*
@@ -835,7 +836,7 @@ cache misses.
 
         private void SetupBlock()
         {
-            int[] cftab = new int[257];
+            Span<int> cftab = stackalloc int[257];
             char ch;
 
             cftab[0] = 0;
@@ -854,7 +855,6 @@ private void SetupBlock()
                 tt[cftab[ch]] = i;
                 cftab[ch]++;
             }
-            cftab = null;
 
             tPos = tt[origPtr];
 

src/SharpCompress/Compressors/BZip2/CBZip2OutputStream.cs

@@ -1,4 +1,5 @@
-using System.IO;
+using System;
+using System.IO;
 
 /*
  * Copyright 2001,2004-2005 The Apache Software Foundation
@@ -88,9 +89,9 @@ private void MakeMaps()
             int nNodes, nHeap, n1, n2, i, j, k;
             bool tooLong;
 
-            int[] heap = new int[BZip2Constants.MAX_ALPHA_SIZE + 2];
-            int[] weight = new int[BZip2Constants.MAX_ALPHA_SIZE * 2];
-            int[] parent = new int[BZip2Constants.MAX_ALPHA_SIZE * 2];
+            Span<int> heap = stackalloc int[BZip2Constants.MAX_ALPHA_SIZE + 2]; // 1040 bytes
+            Span<int> weight = stackalloc int[BZip2Constants.MAX_ALPHA_SIZE * 2];  // 1040 bytes
+            Span<int> parent = stackalloc int[BZip2Constants.MAX_ALPHA_SIZE * 2];  // 1040 bytes
 
             for (i = 0; i < alphaSize; i++)
             {
@@ -1328,8 +1329,8 @@ private void QSort3(int loSt, int hiSt, int dSt)
         private void MainSort()
         {
             int i, j, ss, sb;
-            int[] runningOrder = new int[256];
-            int[] copy = new int[256];
+            Span<int> runningOrder = stackalloc int[256];
+            Span<int> copy = stackalloc int[256];
             bool[] bigDone = new bool[256];
             int c1, c2;
             int numQSorted;

src/SharpCompress/Compressors/Deflate/CRC32.cs

@@ -189,7 +189,7 @@ public void SlurpBlock(byte[] block, int offset, int count)
 
         // pre-initialize the crc table for speed of lookup.
 
-        private uint gf2_matrix_times(uint[] matrix, uint vec)
+        private uint gf2_matrix_times(ReadOnlySpan<uint> matrix, uint vec)
         {
             uint sum = 0;
             int i = 0;
@@ -205,7 +205,7 @@ private uint gf2_matrix_times(uint[] matrix, uint vec)
             return sum;
         }
 
-        private void gf2_matrix_square(uint[] square, uint[] mat)
+        private void gf2_matrix_square(Span<uint> square, Span<uint> mat)
         {
             for (int i = 0; i < 32; i++)
             {
@@ -225,8 +225,8 @@ private void gf2_matrix_square(uint[] square, uint[] mat)
         /// <param name="length">the length of data the CRC value was calculated on</param>
         public void Combine(int crc, int length)
         {
-            var even = new uint[32]; // even-power-of-two zeros operator
-            var odd = new uint[32]; // odd-power-of-two zeros operator
+            Span<uint> even = stackalloc uint[32]; // even-power-of-two zeros operator
+            Span<uint> odd = stackalloc uint[32]; // odd-power-of-two zeros operator
 
             if (length == 0)
             {

src/SharpCompress/Compressors/Deflate/ZlibBaseStream.cs

@@ -413,8 +413,8 @@ private int _ReadAndValidateGzipHeader()
             int totalBytesRead = 0;
 
             // read the header on the first read
-            byte[] header = new byte[10];
-            int n = _stream.Read(header, 0, header.Length);
+            Span<byte> header = stackalloc byte[10];
+            int n = _stream.Read(header);
 
             // workitem 8501: handle edge case (decompress empty stream)
             if (n == 0)
@@ -432,16 +432,16 @@ private int _ReadAndValidateGzipHeader()
                 throw new ZlibException("Bad GZIP header.");
             }
 
-            Int32 timet = BinaryPrimitives.ReadInt32LittleEndian(header.AsSpan(4));
+            int timet = BinaryPrimitives.ReadInt32LittleEndian(header.Slice(4));
             _GzipMtime = TarHeader.EPOCH.AddSeconds(timet);
             totalBytesRead += n;
             if ((header[3] & 0x04) == 0x04)
             {
                 // read and discard extra field
-                n = _stream.Read(header, 0, 2); // 2-byte length field
+                n = _stream.Read(header.Slice(0, 2)); // 2-byte length field
                 totalBytesRead += n;
 
-                Int16 extraLength = (Int16)(header[0] + header[1] * 256);
+                short extraLength = (short)(header[0] + header[1] * 256);
                 byte[] extra = new byte[extraLength];
                 n = _stream.Read(extra, 0, extra.Length);
                 if (n != extraLength)

src/SharpCompress/Compressors/Deflate64/FastEncoderStatus.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
 using System.Diagnostics;
 
 namespace SharpCompress.Compressors.Deflate64
@@ -10,7 +11,7 @@ internal static class FastEncoderStatics
     {
         // static information for encoding, DO NOT MODIFY
 
-        internal static readonly byte[] FAST_ENCODER_TREE_STRUCTURE_DATA =
+        internal static ReadOnlySpan<byte> FAST_ENCODER_TREE_STRUCTURE_DATA => new byte[]
         {
             0xec,0xbd,0x07,0x60,0x1c,0x49,0x96,0x25,0x26,0x2f,0x6d,0xca,
             0x7b,0x7f,0x4a,0xf5,0x4a,0xd7,0xe0,0x74,0xa1,0x08,0x80,0x60,
@@ -23,7 +24,7 @@ internal static class FastEncoderStatics
             0x1f,0x3f
         };
 
-        internal static readonly byte[] B_FINAL_FAST_ENCODER_TREE_STRUCTURE_DATA =
+        internal static ReadOnlySpan<byte> B_FINAL_FAST_ENCODER_TREE_STRUCTURE_DATA => new byte[]
         {
             0xed,0xbd,0x07,0x60,0x1c,0x49,0x96,0x25,0x26,0x2f,0x6d,0xca,
             0x7b,0x7f,0x4a,0xf5,0x4a,0xd7,0xe0,0x74,0xa1,0x08,0x80,0x60,

src/SharpCompress/Compressors/Deflate64/HuffmanTree.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
 using System.Diagnostics;
 using System.IO;
 
@@ -118,14 +119,14 @@ private static byte[] GetStaticDistanceTreeLength()
         // This algorithm is described in standard RFC 1951
         private uint[] CalculateHuffmanCode()
         {
-            uint[] bitLengthCount = new uint[17];
+            Span<uint> bitLengthCount = stackalloc uint[17];
             foreach (int codeLength in _codeLengthArray)
             {
                 bitLengthCount[codeLength]++;
             }
             bitLengthCount[0] = 0;  // clear count for length 0
 
-            uint[] nextCode = new uint[17];
+            Span<uint> nextCode = stackalloc uint[17];
             uint tempCode = 0;
             for (int bits = 1; bits <= 16; bits++)
             {

src/SharpCompress/Compressors/LZMA/LZipStream.cs

@@ -168,9 +168,10 @@ public static int ValidateAndReadSize(Stream stream)
             {
                 throw new ArgumentNullException(nameof(stream));
             }
+
             // Read the header
-            byte[] header = new byte[6];
-            int n = stream.Read(header, 0, header.Length);
+            Span<byte> header = stackalloc byte[6];
+            int n = stream.Read(header);
 
             // TODO: Handle reading only part of the header?
 

src/SharpCompress/Compressors/Rar/UnpackV1/UnpackUtility.cs

@@ -1,4 +1,5 @@
 using System;
+
 using SharpCompress.Compressors.Rar.VM;
 
 namespace SharpCompress.Compressors.Rar.UnpackV1
@@ -182,8 +183,8 @@ internal static int decodeNumber(this BitInput input, Decode.Decode dec)
 
         internal static void makeDecodeTables(byte[] lenTab, int offset, Decode.Decode dec, int size)
         {
-            int[] lenCount = new int[16];
-            int[] tmpPos = new int[16];
+            Span<int> lenCount = stackalloc int[16];
+            Span<int> tmpPos = stackalloc int[16];
             int i;
             long M, N;
 

src/SharpCompress/Compressors/Rar/UnpackV2017/unpack_hpp.cs

@@ -12,6 +12,7 @@
 using System.Collections.Generic;
 using static SharpCompress.Compressors.Rar.UnpackV2017.PackDef;
 using static SharpCompress.Compressors.Rar.UnpackV2017.UnpackGlobal;
+using System;
 
 // TODO: REMOVE THIS... WIP
 #pragma warning disable 169
@@ -271,8 +272,8 @@ internal partial class Unpack
     byte *ReadBufMT;
 #endif
 
-    private byte[] FilterSrcMemory = new byte[0];
-    private byte[] FilterDstMemory = new byte[0];
+    private byte[] FilterSrcMemory = Array.Empty<byte>();
+    private byte[] FilterDstMemory = Array.Empty<byte>();
 
     // Filters code, one entry per filter.
     private readonly List<UnpackFilter> Filters = new List<UnpackFilter>();

src/SharpCompress/Crypto/IBlockCipher.cs

@@ -1,4 +1,6 @@
-namespace SharpCompress.Crypto
+using System;
+
+namespace SharpCompress.Crypto
 {
     /// <remarks>Base interface for a symmetric key block cipher.</remarks>
     public interface IBlockCipher
@@ -19,12 +21,10 @@ public interface IBlockCipher
 
         /// <summary>Process a block.</summary>
         /// <param name="inBuf">The input buffer.</param>
-        /// <param name="inOff">The offset into <paramref>inBuf</paramref> that the input block begins.</param>
         /// <param name="outBuf">The output buffer.</param>
-        /// <param name="outOff">The offset into <paramref>outBuf</paramref> to write the output block.</param>
         /// <exception cref="DataLengthException">If input block is wrong size, or outBuf too small.</exception>
         /// <returns>The number of bytes processed and produced.</returns>
-        int ProcessBlock(byte[] inBuf, int inOff, byte[] outBuf, int outOff);
+        int ProcessBlock(ReadOnlySpan<byte> inBuf, Span<byte> outBuf);
 
         /// <summary>
         /// Reset the cipher to the same state as it was after the last init (if there was one).