Base64Encoder
class Base64Encoder
using System;
using System.IO;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
namespace Newtonsoft.Json.Utilities
{
[System.Runtime.CompilerServices.NullableContext(1)]
[System.Runtime.CompilerServices.Nullable(0)]
internal class Base64Encoder
{
private const int Base64LineSize = 76;
private const int LineSizeInBytes = 57;
private readonly char[] _charsLine = new char[76];
private readonly TextWriter _writer;
[System.Runtime.CompilerServices.Nullable(2)]
private byte[] _leftOverBytes;
private int _leftOverBytesCount;
public Base64Encoder(TextWriter writer)
{
ValidationUtils.ArgumentNotNull(writer, "writer");
_writer = writer;
}
private void ValidateEncode(byte[] buffer, int index, int count)
{
if (buffer == null)
throw new ArgumentNullException("buffer");
if (index < 0)
throw new ArgumentOutOfRangeException("index");
if (count < 0)
throw new ArgumentOutOfRangeException("count");
if (count > buffer.Length - index)
throw new ArgumentOutOfRangeException("count");
}
public void Encode(byte[] buffer, int index, int count)
{
ValidateEncode(buffer, index, count);
if (_leftOverBytesCount > 0) {
if (FulfillFromLeftover(buffer, index, ref count))
return;
int count2 = Convert.ToBase64CharArray(_leftOverBytes, 0, 3, _charsLine, 0);
WriteChars(_charsLine, 0, count2);
}
StoreLeftOverBytes(buffer, index, ref count);
int num = index + count;
int num2 = 57;
while (index < num) {
if (index + num2 > num)
num2 = num - index;
int count3 = Convert.ToBase64CharArray(buffer, index, num2, _charsLine, 0);
WriteChars(_charsLine, 0, count3);
index += num2;
}
}
private void StoreLeftOverBytes(byte[] buffer, int index, ref int count)
{
int num = count % 3;
if (num > 0) {
count -= num;
if (_leftOverBytes == null)
_leftOverBytes = new byte[3];
for (int i = 0; i < num; i++) {
_leftOverBytes[i] = buffer[index + count + i];
}
}
_leftOverBytesCount = num;
}
private bool FulfillFromLeftover(byte[] buffer, int index, ref int count)
{
int num = _leftOverBytesCount;
while (num < 3 && count > 0) {
_leftOverBytes[num++] = buffer[index++];
count--;
}
if (count == 0 && num < 3) {
_leftOverBytesCount = num;
return true;
}
return false;
}
public void Flush()
{
if (_leftOverBytesCount > 0) {
int count = Convert.ToBase64CharArray(_leftOverBytes, 0, _leftOverBytesCount, _charsLine, 0);
WriteChars(_charsLine, 0, count);
_leftOverBytesCount = 0;
}
}
private void WriteChars(char[] chars, int index, int count)
{
_writer.Write(chars, index, count);
}
[AsyncStateMachine(typeof(<EncodeAsync>d__13))]
public Task EncodeAsync(byte[] buffer, int index, int count, CancellationToken cancellationToken)
{
<EncodeAsync>d__13 stateMachine = default(<EncodeAsync>d__13);
stateMachine.<>t__builder = AsyncTaskMethodBuilder.Create();
stateMachine.<>4__this = this;
stateMachine.buffer = buffer;
stateMachine.index = index;
stateMachine.count = count;
stateMachine.cancellationToken = cancellationToken;
stateMachine.<>1__state = -1;
stateMachine.<>t__builder.Start(ref stateMachine);
return stateMachine.<>t__builder.Task;
}
private Task WriteCharsAsync(char[] chars, int index, int count, CancellationToken cancellationToken)
{
return _writer.WriteAsync(chars, index, count, cancellationToken);
}
public Task FlushAsync(CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested)
return cancellationToken.FromCanceled();
if (_leftOverBytesCount > 0) {
int count = Convert.ToBase64CharArray(_leftOverBytes, 0, _leftOverBytesCount, _charsLine, 0);
_leftOverBytesCount = 0;
return WriteCharsAsync(_charsLine, 0, count, cancellationToken);
}
return AsyncUtils.CompletedTask;
}
}
}