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using System.Text;
using System.Diagnostics;
using System.Threading.Tasks;
namespace System.Xml {
internal abstract partial class Base64Encoder {
internal abstract Task WriteCharsAsync(char[] chars, int index, int count);
internal async Task EncodeAsync( 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" );
}
// encode left-over buffer
if( leftOverBytesCount > 0 ) {
int i = leftOverBytesCount;
while ( i < 3 && count > 0 ) {
leftOverBytes[i++] = buffer[index++];
count--;
}
// the total number of buffer we have is less than 3 -> return
if ( count == 0 && i < 3 ) {
leftOverBytesCount = i;
return;
}
// encode the left-over buffer and write out
int leftOverChars = Convert.ToBase64CharArray( leftOverBytes, 0, 3, charsLine, 0 );
await WriteCharsAsync( charsLine, 0, leftOverChars ).ConfigureAwait(false);
}
// store new left-over buffer
leftOverBytesCount = count % 3;
if ( leftOverBytesCount > 0 ) {
count -= leftOverBytesCount;
if ( leftOverBytes == null ) {
leftOverBytes = new byte[3];
}
for( int i = 0; i < leftOverBytesCount; i++ ) {
leftOverBytes[i] = buffer[ index + count + i ];
}
}
// encode buffer in 76 character long chunks
int endIndex = index + count;
int chunkSize = LineSizeInBytes;
while( index < endIndex ) {
if ( index + chunkSize > endIndex ) {
chunkSize = endIndex - index;
}
int charCount = Convert.ToBase64CharArray( buffer, index, chunkSize, charsLine, 0 );
await WriteCharsAsync( charsLine, 0, charCount ).ConfigureAwait(false);
index += chunkSize;
}
}
internal async Task FlushAsync() {
if ( leftOverBytesCount > 0 ) {
int leftOverChars = Convert.ToBase64CharArray( leftOverBytes, 0, leftOverBytesCount, charsLine, 0 );
await WriteCharsAsync( charsLine, 0, leftOverChars ).ConfigureAwait(false);
leftOverBytesCount = 0;
}
}
}
internal partial class XmlTextWriterBase64Encoder : Base64Encoder {
internal override Task WriteCharsAsync(char[] chars, int index, int count) {
throw new NotImplementedException();
}
}
internal partial class XmlRawWriterBase64Encoder : Base64Encoder {
internal override Task WriteCharsAsync( char[] chars, int index, int count ) {
return rawWriter.WriteRawAsync( chars, index, count );
}
}
}
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