Use Buffer.BlockCopy with byte[]

In particular after dotnet/coreclr#3118, Buffer.BlockCopy has less overhead than Array.Copy when copying byte[]s, such that there's no benefit to using Array.Copy and potential benefit to using Buffer.BlockCopy.

This commit replaces usage of Array.Copy(byte[], ...) in corefx with Buffer.BlockCopy(byte[], ...).  A lot of places were already using it.

(In a few places where we weren't passing lower bounds to Array.Copy with T[] arguments, I added explicit lower bounds as well to avoid the overload needing to call GetLowerBound.)

Author: stephentoub

src/Common/src/System/Net/Logging/GlobalLog.cs

@@ -248,7 +248,7 @@ public static void Dump(byte[] buffer, int offset, int length)
             }
 
             var bufferSegment = new byte[length];
-            Array.Copy(buffer, offset, bufferSegment, 0, length);
+            Buffer.BlockCopy(buffer, offset, bufferSegment, 0, length);
             EventSourceLogging.Log.DebugDumpArray(bufferSegment);
         }
 

src/Common/src/System/Security/Cryptography/RSAOpenSsl.cs

@@ -108,7 +108,7 @@ public override byte[] Decrypt(byte[] data, RSAEncryptionPadding padding)
             }
 
             byte[] plainBytes = new byte[returnValue];
-            Array.Copy(buf, 0, plainBytes, 0, returnValue);
+            Buffer.BlockCopy(buf, 0, plainBytes, 0, returnValue);
             return plainBytes;
         }
 

src/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/Semantics/Symbols/SymbolManagerBase.cs

@@ -400,7 +400,7 @@ public TypeArray AllocParams(params CType[] types)
         public TypeArray ConcatParams(CType[] prgtype1, CType[] prgtype2)
         {
             CType[] combined = new CType[prgtype1.Length + prgtype2.Length];
-            Array.Copy(prgtype1, combined, prgtype1.Length);
+            Array.Copy(prgtype1, 0, combined, 0, prgtype1.Length);
             Array.Copy(prgtype2, 0, combined, prgtype1.Length, prgtype2.Length);
             return AllocParams(combined);
         }

src/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/UIHintAttribute.cs

@@ -100,7 +100,7 @@ public UIHintImplementation(string uiHint, string presentationLayer, params obje
                 if (controlParameters != null)
                 {
                     _inputControlParameters = new object[controlParameters.Length];
-                    Array.Copy(controlParameters, _inputControlParameters, controlParameters.Length);
+                    Array.Copy(controlParameters, 0, _inputControlParameters, 0, controlParameters.Length);
                 }
             }
 

src/System.Data.SqlClient/src/System/Data/Common/DataRecordInternal.cs

@@ -143,7 +143,7 @@ public override long GetBytes(int i, long dataIndex, byte[] buffer, int bufferIn
                 }
 
                 // until arrays are 64 bit, we have to do these casts
-                Array.Copy(data, ndataIndex, buffer, bufferIndex, (int)cbytes);
+                Buffer.BlockCopy(data, ndataIndex, buffer, bufferIndex, (int)cbytes);
             }
             catch (Exception e)
             {

src/System.Data.SqlClient/src/System/Data/Sql/SqlMetaData.cs

@@ -942,7 +942,7 @@ public SqlBinary Adjust(SqlBinary value)
                     {
                         byte[] rgbValue = value.Value;
                         byte[] rgbNewValue = new byte[MaxLength];
-                        Array.Copy(rgbValue, 0, rgbNewValue, 0, rgbValue.Length);
+                        Buffer.BlockCopy(rgbValue, 0, rgbNewValue, 0, rgbValue.Length);
                         Array.Clear(rgbNewValue, rgbValue.Length, rgbNewValue.Length - rgbValue.Length);
                         return new SqlBinary(rgbNewValue);
                     }
@@ -963,7 +963,7 @@ public SqlBinary Adjust(SqlBinary value)
             {
                 byte[] rgbValue = value.Value;
                 byte[] rgbNewValue = new byte[MaxLength];
-                Array.Copy(rgbValue, 0, rgbNewValue, 0, (int)MaxLength);
+                Buffer.BlockCopy(rgbValue, 0, rgbNewValue, 0, (int)MaxLength);
                 value = new SqlBinary(rgbNewValue);
             }
 
@@ -1040,7 +1040,7 @@ public SqlBytes Adjust(SqlBytes value)
                         if (value.MaxLength < MaxLength)
                         {
                             byte[] rgbNew = new byte[MaxLength];
-                            Array.Copy(value.Buffer, 0, rgbNew, 0, (int)oldLength);
+                            Buffer.BlockCopy(value.Buffer, 0, rgbNew, 0, (int)oldLength);
                             value = new SqlBytes(rgbNew);
                         }
 
@@ -1380,7 +1380,7 @@ public byte[] Adjust(byte[] value)
                     if (value.Length < MaxLength)
                     {
                         byte[] rgbNewValue = new byte[MaxLength];
-                        Array.Copy(value, 0, rgbNewValue, 0, value.Length);
+                        Buffer.BlockCopy(value, 0, rgbNewValue, 0, value.Length);
                         Array.Clear(rgbNewValue, value.Length, (int)rgbNewValue.Length - value.Length);
                         return rgbNewValue;
                     }
@@ -1400,7 +1400,7 @@ public byte[] Adjust(byte[] value)
             if (value.Length > MaxLength && Max != MaxLength)
             {
                 byte[] rgbNewValue = new byte[MaxLength];
-                Array.Copy(value, 0, rgbNewValue, 0, (int)MaxLength);
+                Buffer.BlockCopy(value, 0, rgbNewValue, 0, (int)MaxLength);
                 value = rgbNewValue;
             }
 

src/System.Data.SqlClient/src/System/Data/SqlClient/SNI/SNIPacket.cs

@@ -124,7 +124,7 @@ public SNIPacket Clone()
         {
             SNIPacket packet = new SNIPacket(null);
             packet._data = new byte[_length];
-            Array.Copy(_data, 0, packet._data, 0, _length);
+            Buffer.BlockCopy(_data, 0, packet._data, 0, _length);
             packet._length = _length;
 
             return packet;

src/System.Data.SqlClient/src/System/Data/SqlClient/SqlDataReader.cs

@@ -1374,7 +1374,7 @@ private bool TryGetBytesInternal(int i, long dataIndex, byte[] buffer, int buffe
                         cbytes = length;
                 }
 
-                Array.Copy(data, ndataIndex, buffer, bufferIndex, cbytes);
+                Buffer.BlockCopy(data, ndataIndex, buffer, bufferIndex, cbytes);
             }
             catch (Exception e)
             {

src/System.Data.SqlClient/src/System/Data/SqlClient/SqlSequentialTextReader.cs

@@ -371,7 +371,7 @@ private byte[] PrepareByteBuffer(int numberOfChars, out int byteBufferUsed)
                     {
                         // Otherwise, copy over the leftover buffer
                         byteBuffer = new byte[byteBufferSize];
-                        Array.Copy(_leftOverBytes, byteBuffer, _leftOverBytes.Length);
+                        Buffer.BlockCopy(_leftOverBytes, 0, byteBuffer, 0, _leftOverBytes.Length);
                         byteBufferUsed = _leftOverBytes.Length;
                     }
                 }
@@ -410,7 +410,7 @@ private int DecodeBytesToChars(byte[] inBuffer, int inBufferCount, char[] outBuf
             if ((!completed) && (bytesUsed < inBufferCount))
             {
                 _leftOverBytes = new byte[inBufferCount - bytesUsed];
-                Array.Copy(inBuffer, bytesUsed, _leftOverBytes, 0, _leftOverBytes.Length);
+                Buffer.BlockCopy(inBuffer, bytesUsed, _leftOverBytes, 0, _leftOverBytes.Length);
             }
             else
             {

src/System.Data.SqlClient/src/System/Data/SqlClient/SqlStream.cs

@@ -452,7 +452,7 @@ override public int Read(byte[] buffer, int offset, int count)
                 cb = _cachedBytes[_currentArrayIndex].Length - _currentPosition;
                 if (cb > count)
                     cb = count;
-                Array.Copy(_cachedBytes[_currentArrayIndex], _currentPosition, buffer, offset, cb);
+                Buffer.BlockCopy(_cachedBytes[_currentArrayIndex], _currentPosition, buffer, offset, cb);
 
                 _currentPosition += cb;
                 count -= (int)cb;

src/System.Data.SqlClient/src/System/Data/SqlTypes/SQLBytes.cs

@@ -194,7 +194,7 @@ public byte[] Value
 
                     default:
                         buffer = new byte[_lCurLen];
-                        Array.Copy(m_rgbBuf, buffer, (int)_lCurLen);
+                        Buffer.BlockCopy(m_rgbBuf, 0, buffer, 0, (int)_lCurLen);
                         break;
                 }
 
@@ -343,7 +343,7 @@ public long Read(long offset, byte[] buffer, int offsetInBuffer, int count)
                     default:
                         // ProjectK\Core doesn't support long-typed array indexers
                         Debug.Assert(offset < int.MaxValue);
-                        Array.Copy(m_rgbBuf, checked((int)offset), buffer, offsetInBuffer, count);
+                        Buffer.BlockCopy(m_rgbBuf, checked((int)offset), buffer, offsetInBuffer, count);
                         break;
                 }
             }
@@ -409,7 +409,7 @@ public void Write(long offset, byte[] buffer, int offsetInBuffer, int count)
                 {
                     // ProjectK\Core doesn't support long-typed array indexers
                     Debug.Assert(offset < int.MaxValue);
-                    Array.Copy(buffer, offsetInBuffer, m_rgbBuf, checked((int)offset), count);
+                    Buffer.BlockCopy(buffer, offsetInBuffer, m_rgbBuf, checked((int)offset), count);
 
                     // If the last position that has been written is after
                     // the current data length, reset the length

src/System.Data.SqlClient/src/System/Data/SqlTypes/SQLChars.cs

@@ -186,7 +186,7 @@ public char[] Value
 
                     default:
                         buffer = new char[_lCurLen];
-                        Array.Copy(m_rgchBuf, buffer, (int)_lCurLen);
+                        Array.Copy(m_rgchBuf, 0, buffer, 0, (int)_lCurLen);
                         break;
                 }
 

src/System.Diagnostics.Tracing/src/System/Diagnostics/Tracing/EventCounter.cs

@@ -285,7 +285,7 @@ private static void EnsureEventSourceIndexAvailable(int eventSourceIndex)
             else if (eventSourceIndex >= EventCounterGroup.s_eventCounterGroups.Length)
             {
                 EventCounterGroup[] newEventCounterGroups = new EventCounterGroup[eventSourceIndex + 1];
-                Array.Copy(EventCounterGroup.s_eventCounterGroups, newEventCounterGroups, EventCounterGroup.s_eventCounterGroups.Length);
+                Array.Copy(EventCounterGroup.s_eventCounterGroups, 0, newEventCounterGroups, 0, EventCounterGroup.s_eventCounterGroups.Length);
                 EventCounterGroup.s_eventCounterGroups = newEventCounterGroups;
             }
         }

src/System.Diagnostics.Tracing/src/System/Diagnostics/Tracing/EventSource.cs

@@ -3645,7 +3645,7 @@ private static void AddEventDescriptor(ref EventMetadata[] eventData, string eve
             if (eventData == null || eventData.Length <= eventAttribute.EventId)
             {
                 EventMetadata[] newValues = new EventMetadata[Math.Max(eventData.Length + 16, eventAttribute.EventId + 1)];
-                Array.Copy(eventData, newValues, eventData.Length);
+                Array.Copy(eventData, 0, newValues, 0, eventData.Length);
                 eventData = newValues;
             }
 
@@ -3684,7 +3684,7 @@ private static void TrimEventDescriptors(ref EventMetadata[] eventData)
             if (eventData.Length - idx > 2)      // allow one wasted slot. 
             {
                 EventMetadata[] newValues = new EventMetadata[idx + 1];
-                Array.Copy(eventData, newValues, newValues.Length);
+                Array.Copy(eventData, 0, newValues, 0, newValues.Length);
                 eventData = newValues;
             }
         }

src/System.IO/src/System/IO/BufferedStream.cs

@@ -134,7 +134,7 @@ private void EnsureShadowBufferAllocated()
                 return;
 
             byte[] shadowBuffer = new byte[Math.Min(_bufferSize + _bufferSize, MaxShadowBufferSize)];
-            Array.Copy(_buffer, 0, shadowBuffer, 0, _writePos);
+            Buffer.BlockCopy(_buffer, 0, shadowBuffer, 0, _writePos);
             _buffer = shadowBuffer;
         }
 
@@ -416,7 +416,7 @@ private int ReadFromBuffer(byte[] array, int offset, int count)
 
             if (readbytes > count)
                 readbytes = count;
-            Array.Copy(_buffer, _readPos, array, offset, readbytes);
+            Buffer.BlockCopy(_buffer, _readPos, array, offset, readbytes);
             _readPos += readbytes;
 
             return readbytes;
@@ -683,7 +683,7 @@ private void WriteToBuffer(byte[] array, ref int offset, ref int count)
                 return;
 
             EnsureBufferAllocated();
-            Array.Copy(array, offset, _buffer, _writePos, bytesToWrite);
+            Buffer.BlockCopy(array, offset, _buffer, _writePos, bytesToWrite);
 
             _writePos += bytesToWrite;
             count -= bytesToWrite;
@@ -825,7 +825,7 @@ public override void Write(byte[] array, int offset, int count)
                     if (totalUserbytes <= (_bufferSize + _bufferSize) && totalUserbytes <= MaxShadowBufferSize)
                     {
                         EnsureShadowBufferAllocated();
-                        Array.Copy(array, offset, _buffer, _writePos, count);
+                        Buffer.BlockCopy(array, offset, _buffer, _writePos, count);
                         _stream.Write(_buffer, 0, totalUserbytes);
                         _writePos = 0;
                         return;
@@ -977,7 +977,7 @@ private async Task WriteToUnderlyingStreamAsync(byte[] array, int offset, int co
                         if (totalUserBytes <= (_bufferSize + _bufferSize) && totalUserBytes <= MaxShadowBufferSize)
                         {
                             EnsureShadowBufferAllocated();
-                            Array.Copy(array, offset, _buffer, _writePos, count);
+                            Buffer.BlockCopy(array, offset, _buffer, _writePos, count);
 
                             await _stream.WriteAsync(_buffer, 0, totalUserBytes, cancellationToken).ConfigureAwait(false);
                             _writePos = 0;

src/System.Net.Http/src/System/Net/Http/Unix/CurlHandler.CurlResponseMessage.cs

@@ -282,7 +282,7 @@ public override Task<int> ReadAsync(byte[] buffer, int offset, int count, Cancel
                     if (_remainingDataCount > 0)
                     {
                         int bytesToCopy = Math.Min(count, _remainingDataCount);
-                        Array.Copy(_remainingData, _remainingDataOffset, buffer, offset, bytesToCopy);
+                        Buffer.BlockCopy(_remainingData, _remainingDataOffset, buffer, offset, bytesToCopy);
 
                         _remainingDataOffset += bytesToCopy;
                         _remainingDataCount -= bytesToCopy;

src/System.Net.NetworkInformation/src/System/Net/NetworkInformation/SystemNetworkInterface.cs

@@ -173,9 +173,9 @@ public override PhysicalAddress GetPhysicalAddress()
         {
             byte[] newAddr = new byte[_addressLength];
 
-            // Array.Copy only supports int and long while addressLength is uint (see IpAdapterAddresses).
+            // Buffer.BlockCopy only supports int while addressLength is uint (see IpAdapterAddresses).
             // Will throw OverflowException if addressLength > Int32.MaxValue.
-            Array.Copy(_physicalAddress, 0, newAddr, 0, checked((int)_addressLength));
+            Buffer.BlockCopy(_physicalAddress, 0, newAddr, 0, checked((int)_addressLength));
             return new PhysicalAddress(newAddr);
         }
 

src/System.Net.Ping/src/System/Net/NetworkInformation/Ping.Unix.cs

@@ -113,7 +113,7 @@ private async Task<PingReply> SendIcmpEchoRequestOverRawSocket(IPAddress address
                     int dataOffset = ipHeaderLength + IcmpHeaderLengthInBytes;
                     // We want to return a buffer with the actual data we sent out, not including the header data.
                     byte[] dataBuffer = new byte[bytesReceived - dataOffset];
-                    Array.Copy(receiveBuffer, dataOffset, dataBuffer, 0, dataBuffer.Length);
+                    Buffer.BlockCopy(receiveBuffer, dataOffset, dataBuffer, 0, dataBuffer.Length);
 
                     IPStatus status = isIpv4
                                         ? IcmpV4MessageConstants.MapV4TypeToIPStatus(type, code)

src/System.Net.Sockets/src/System/Net/Sockets/Socket.cs

@@ -4116,7 +4116,7 @@ internal Socket EndAccept(out byte[] buffer, IAsyncResult asyncResult)
 
             Socket socket = EndAccept(out innerBuffer, out bytesTransferred, asyncResult);
             buffer = new byte[bytesTransferred];
-            Array.Copy(innerBuffer, 0, buffer, 0, bytesTransferred);
+            Buffer.BlockCopy(innerBuffer, 0, buffer, 0, bytesTransferred);
             return socket;
         }
 

src/System.Private.DataContractSerialization/src/System/Xml/XmlBaseReader.cs

@@ -1370,9 +1370,9 @@ private int ReadBytes(Encoding encoding, int byteBlock, int charBlock, byte[] bu
             if (_trailByteCount > 0)
             {
                 int actual = Math.Min(_trailByteCount, byteCount);
-                Array.Copy(_trailBytes, 0, buffer, offset, actual);
+                Buffer.BlockCopy(_trailBytes, 0, buffer, offset, actual);
                 _trailByteCount -= actual;
-                Array.Copy(_trailBytes, actual, _trailBytes, 0, _trailByteCount);
+                Buffer.BlockCopy(_trailBytes, actual, _trailBytes, 0, _trailByteCount);
                 return actual;
             }
             XmlNodeType nodeType = _node.NodeType;
@@ -1440,9 +1440,9 @@ private int ReadBytes(Encoding encoding, int byteBlock, int charBlock, byte[] bu
                             _trailBytes = new byte[3];
                         _trailByteCount = encoding.GetBytes(chars, 0, charCount, _trailBytes, 0);
                         int actual = Math.Min(_trailByteCount, byteCount);
-                        Array.Copy(_trailBytes, 0, buffer, offset, actual);
+                        Buffer.BlockCopy(_trailBytes, 0, buffer, offset, actual);
                         _trailByteCount -= actual;
-                        Array.Copy(_trailBytes, actual, _trailBytes, 0, _trailByteCount);
+                        Buffer.BlockCopy(_trailBytes, actual, _trailBytes, 0, _trailByteCount);
                         return actual;
                     }
                     else

src/System.Private.DataContractSerialization/src/System/Xml/XmlStreamNodeWriter.cs

@@ -467,7 +467,7 @@ unsafe protected int UnsafeGetUTF8Chars(char* chars, int charCount, byte[] buffe
                         string tmp = new string(charsStart, 0, (int)(chars - charsStart));
                         byte[] newBytes = _encoding != null ? _encoding.GetBytes(tmp) : s_UTF8Encoding.GetBytes(tmp);
                         int toCopy = Math.Min(newBytes.Length, (int)(bytesMax - bytes));
-                        Array.Copy(newBytes, 0, buffer, (int)(bytes - _bytes) + offset, toCopy);
+                        Buffer.BlockCopy(newBytes, 0, buffer, (int)(bytes - _bytes) + offset, toCopy);
 
                         bytes += toCopy;
 

src/System.Reflection.Metadata/src/System/Reflection/BlobBuilder.cs

@@ -305,7 +305,7 @@ public byte[] ToArray(int start, int byteCount)
                         break;
                     }
 
-                    Array.Copy(chunk._buffer, Math.Max(start - chunkStartPosition, 0), result, resultOffset, bytesToCopy);
+                    Buffer.BlockCopy(chunk._buffer, Math.Max(start - chunkStartPosition, 0), result, resultOffset, bytesToCopy);
 
                     resultOffset += bytesToCopy;
                 }

src/System.Reflection.Metadata/src/System/Reflection/BlobWriter.cs

@@ -108,7 +108,7 @@ public byte[] ToArray(int start, int byteCount)
             BlobUtilities.ValidateRange(Length, start, byteCount);
 
             var result = new byte[byteCount];
-            Array.Copy(_buffer, _start + start, result, 0, byteCount);
+            Buffer.BlockCopy(_buffer, _start + start, result, 0, byteCount);
             return result;
         }
 

src/System.Runtime.WindowsRuntime/src/System/IO/BufferedStream.cs

@@ -170,7 +170,7 @@ private void EnsureShadowBufferAllocated()
                 return;
 
             Byte[] shadowBuffer = new Byte[Math.Min(_bufferSize + _bufferSize, MaxShadowBufferSize)];
-            Array.Copy(_buffer, 0, shadowBuffer, 0, _writePos);
+            Buffer.BlockCopy(_buffer, 0, shadowBuffer, 0, _writePos);
             _buffer = shadowBuffer;
         }
 
@@ -485,7 +485,7 @@ private Int32 ReadFromBuffer(Byte[] array, Int32 offset, Int32 count)
 
             if (readBytes > count)
                 readBytes = count;
-            Array.Copy(_buffer, _readPos, array, offset, readBytes);
+            Buffer.BlockCopy(_buffer, _readPos, array, offset, readBytes);
             _readPos += readBytes;
 
             return readBytes;
@@ -842,7 +842,7 @@ private void WriteToBuffer(Byte[] array, ref Int32 offset, ref Int32 count)
                 return;
 
             EnsureBufferAllocated();
-            Array.Copy(array, offset, _buffer, _writePos, bytesToWrite);
+            Buffer.BlockCopy(array, offset, _buffer, _writePos, bytesToWrite);
 
             _writePos += bytesToWrite;
             count -= bytesToWrite;
@@ -986,7 +986,7 @@ public override void Write(Byte[] array, Int32 offset, Int32 count)
                     if (totalUserBytes <= (_bufferSize + _bufferSize) && totalUserBytes <= MaxShadowBufferSize)
                     {
                         EnsureShadowBufferAllocated();
-                        Array.Copy(array, offset, _buffer, _writePos, count);
+                        Buffer.BlockCopy(array, offset, _buffer, _writePos, count);
                         _stream.Write(_buffer, 0, totalUserBytes);
                         _writePos = 0;
                         return;

src/System.Runtime.WindowsRuntime/src/System/Runtime/InteropServices/WindowsRuntime/WindowsRuntimeBuffer.cs

@@ -65,7 +65,7 @@ public static IBuffer Create(Byte[] data, Int32 offset, Int32 length, Int32 capa
             Contract.EndContractBlock();
 
             Byte[] underlyingData = new Byte[capacity];
-            Array.Copy(data, offset, underlyingData, 0, length);
+            Buffer.BlockCopy(data, offset, underlyingData, 0, length);
             return new WindowsRuntimeBuffer(underlyingData, 0, length, capacity);
         }