Base64Encoder.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Xml / System / Xml / Base64Encoder.cs / 1305376 / Base64Encoder.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
//-----------------------------------------------------------------------------
 
using System.Text; 
using System.Diagnostics;
 
namespace System.Xml {

    internal abstract class Base64Encoder {
 
        byte[]  leftOverBytes;
        int     leftOverBytesCount; 
        char[]  charsLine; 

        internal const int Base64LineSize = 76; 
        internal const int LineSizeInBytes = Base64LineSize/4*3;

        internal Base64Encoder() {
            charsLine = new char[Base64LineSize]; 
        }
 
        internal abstract void WriteChars( char[] chars, int index, int count ); 

        internal void Encode( 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 );
                WriteChars( charsLine, 0, leftOverChars );
            } 

            // 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 ); 
                WriteChars( charsLine, 0, charCount );
 
                index += chunkSize;
            }
        }
 
        internal void Flush() {
            if ( leftOverBytesCount > 0 ) { 
                int leftOverChars = Convert.ToBase64CharArray( leftOverBytes, 0, leftOverBytesCount, charsLine, 0 ); 
                WriteChars( charsLine, 0, leftOverChars );
                leftOverBytesCount = 0; 
            }
        }
    }
 
    internal class XmlRawWriterBase64Encoder : Base64Encoder {
        XmlRawWriter rawWriter; 
 
        internal XmlRawWriterBase64Encoder( XmlRawWriter rawWriter ) {
            this.rawWriter = rawWriter; 
        }

        internal override void WriteChars( char[] chars, int index, int count ) {
            rawWriter.WriteRaw( chars, index, count ); 
       }
    } 
 
#if !SILVERLIGHT
    internal class XmlTextWriterBase64Encoder : Base64Encoder { 
        XmlTextEncoder xmlTextEncoder;

        internal XmlTextWriterBase64Encoder( XmlTextEncoder xmlTextEncoder ) {
            this.xmlTextEncoder = xmlTextEncoder; 
        }
 
        internal override void WriteChars( char[] chars, int index, int count ) { 
            xmlTextEncoder.WriteRaw( chars, index, count );
        } 
    }
#endif
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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