ReadContentAsBinaryHelper.cs source code in C# .NET

                        Code:
                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Xml / System / Xml / Core / ReadContentAsBinaryHelper.cs / 1 / ReadContentAsBinaryHelper.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
//-----------------------------------------------------------------------------
 
using System.Diagnostics; 

namespace System.Xml 
{
    internal class ReadContentAsBinaryHelper {
// Private enums
        enum State { 
            None,
            InReadContent, 
            InReadElementContent, 
        }
 
// Fields
        XmlReader   reader;
        State       state;
        int         valueOffset; 
        bool        isEnd;
 
        bool        canReadValueChunk; 
        char[]      valueChunk;
        int         valueChunkLength; 

        IncrementalReadDecoder decoder;
        Base64Decoder          base64Decoder;
        BinHexDecoder          binHexDecoder; 

// Constants 
        const int ChunkSize = 256; 

// Constructor 
        internal ReadContentAsBinaryHelper( XmlReader reader ) {
            this.reader = reader;
            this.canReadValueChunk = reader.CanReadValueChunk;
 
            if ( canReadValueChunk ) {
                valueChunk = new char[ChunkSize]; 
            } 
        }
 
// Static methods
        internal static ReadContentAsBinaryHelper CreateOrReset( ReadContentAsBinaryHelper helper, XmlReader reader ) {
            if ( helper == null ) {
                return new ReadContentAsBinaryHelper( reader ); 
            }
            else { 
                helper.Reset(); 
                return helper;
            } 
        }

// Internal methods
 
        internal int ReadContentAsBase64( byte[] buffer, int index, int count ) {
            // check arguments 
            if ( buffer == null ) { 
                throw new ArgumentNullException( "buffer" );
            } 
            if ( count < 0 ) {
                throw new ArgumentOutOfRangeException( "count" );
            }
            if ( index < 0 ) { 
                throw new ArgumentOutOfRangeException( "index" );
            } 
            if ( buffer.Length - index < count ) { 
                throw new ArgumentOutOfRangeException( "count" );
            } 

            switch ( state ) {
                case State.None:
                    if ( !reader.CanReadContentAs() ) { 
                        throw reader.CreateReadContentAsException( "ReadContentAsBase64" );
                    } 
                    if ( !Init() ) { 
                        return 0;
                    } 
                    break;
                case State.InReadContent:
                    // if we have a correct decoder, go read
                    if ( decoder == base64Decoder ) { 
                        // read more binary data
                        return ReadContentAsBinary( buffer, index, count ); 
                    } 
                    break;
                case State.InReadElementContent: 
                    throw new InvalidOperationException( Res.GetString( Res.Xml_MixingBinaryContentMethods ) );
                default:
                    Debug.Assert( false );
                    return 0; 
            }
 
            Debug.Assert( state == State.InReadContent ); 

            // setup base64 decoder 
            InitBase64Decoder();

            // read more binary data
            return ReadContentAsBinary( buffer, index, count ); 
        }
 
        internal int ReadContentAsBinHex( byte[] buffer, int index, int count ) { 
            // check arguments
            if ( buffer == null ) { 
                throw new ArgumentNullException( "buffer" );
            }
            if ( count < 0 ) {
                throw new ArgumentOutOfRangeException( "count" ); 
            }
            if ( index < 0 ) { 
                throw new ArgumentOutOfRangeException( "index" ); 
            }
            if ( buffer.Length - index < count ) { 
                throw new ArgumentOutOfRangeException( "count" );
            }

            switch ( state ) { 
                case State.None:
                    if ( !reader.CanReadContentAs() ) { 
                        throw reader.CreateReadContentAsException( "ReadContentAsBinHex" ); 
                    }
                    if ( !Init() ) { 
                        return 0;
                    }
                    break;
                case State.InReadContent: 
                    // if we have a correct decoder, go read
                    if ( decoder == binHexDecoder ) { 
                        // read more binary data 
                        return ReadContentAsBinary( buffer, index, count );
                    } 
                    break;
                case State.InReadElementContent:
                    throw new InvalidOperationException( Res.GetString( Res.Xml_MixingBinaryContentMethods ) );
                default: 
                    Debug.Assert( false );
                    return 0; 
            } 

            Debug.Assert( state == State.InReadContent ); 

            // setup binhex decoder
            InitBinHexDecoder();
 
            // read more binary data
            return ReadContentAsBinary( buffer, index, count ); 
        } 

        internal int ReadElementContentAsBase64( byte[] buffer, int index, int count ) { 
            // check arguments
            if ( buffer == null ) {
                throw new ArgumentNullException( "buffer" );
            } 
            if ( count < 0 ) {
                throw new ArgumentOutOfRangeException( "count" ); 
            } 
            if ( index < 0 ) {
                throw new ArgumentOutOfRangeException( "index" ); 
            }
            if ( buffer.Length - index < count ) {
                throw new ArgumentOutOfRangeException( "count" );
            } 

            switch ( state ) { 
                case State.None: 
                    if ( reader.NodeType != XmlNodeType.Element ) {
                        throw reader.CreateReadElementContentAsException( "ReadElementContentAsBase64" ); 
                    }
                    if ( !InitOnElement() ) {
                        return 0;
                    } 
                    break;
                case State.InReadContent: 
                    throw new InvalidOperationException( Res.GetString( Res.Xml_MixingBinaryContentMethods ) ); 
                case State.InReadElementContent:
                    // if we have a correct decoder, go read 
                    if ( decoder == base64Decoder ) {
                        // read more binary data
                        return ReadElementContentAsBinary( buffer, index, count );
                    } 
                    break;
                default: 
                    Debug.Assert( false ); 
                    return 0;
            } 

            Debug.Assert( state == State.InReadElementContent );

            // setup base64 decoder 
            InitBase64Decoder();
 
            // read more binary data 
            return ReadElementContentAsBinary( buffer, index, count );
        } 

        internal int ReadElementContentAsBinHex( byte[] buffer, int index, int count ) {
            // check arguments
            if ( buffer == null ) { 
                throw new ArgumentNullException( "buffer" );
            } 
            if ( count < 0 ) { 
                throw new ArgumentOutOfRangeException( "count" );
            } 
            if ( index < 0 ) {
                throw new ArgumentOutOfRangeException( "index" );
            }
            if ( buffer.Length - index < count ) { 
                throw new ArgumentOutOfRangeException( "count" );
            } 
 
            switch ( state ) {
                case State.None: 
                    if ( reader.NodeType != XmlNodeType.Element ) {
                        throw reader.CreateReadElementContentAsException( "ReadElementContentAsBinHex" );
                    }
                    if ( !InitOnElement() ) { 
                        return 0;
                    } 
                    break; 
                case State.InReadContent:
                    throw new InvalidOperationException( Res.GetString( Res.Xml_MixingBinaryContentMethods ) ); 
                case State.InReadElementContent:
                    // if we have a correct decoder, go read
                    if ( decoder == binHexDecoder ) {
                        // read more binary data 
                        return ReadElementContentAsBinary( buffer, index, count );
                    } 
                    break; 
                default:
                    Debug.Assert( false ); 
                    return 0;
            }

            Debug.Assert( state == State.InReadElementContent ); 

            // setup binhex decoder 
            InitBinHexDecoder(); 

            // read more binary data 
            return ReadElementContentAsBinary( buffer, index, count );
        }

        internal void Finish() { 
            if ( state != State.None ) {
                while ( MoveToNextContentNode( true ) ) 
                    ; 
                if ( state == State.InReadElementContent ) {
                    if ( reader.NodeType != XmlNodeType.EndElement ) { 
                        throw new XmlException( Res.Xml_InvalidNodeType, reader.NodeType.ToString(), reader as IXmlLineInfo );
                    }
                    // move off the EndElement
                    reader.Read(); 
                }
            } 
            Reset(); 
        }
 
        internal void Reset() {
            state = State.None;
            isEnd = false;
            valueOffset = 0; 
        }
 
// Private methods 
        private bool Init() {
            // make sure we are on a content node 
            if ( !MoveToNextContentNode( false ) ) {
                return false;
            }
 
            state = State.InReadContent;
            isEnd = false; 
            return true; 
        }
 
        private bool InitOnElement() {
            Debug.Assert( reader.NodeType == XmlNodeType.Element );
            bool isEmpty = reader.IsEmptyElement;
 
            // move to content or off the empty element
            reader.Read(); 
            if ( isEmpty ) { 
                return false;
            } 

            // make sure we are on a content node
            if ( !MoveToNextContentNode( false ) ) {
                if ( reader.NodeType != XmlNodeType.EndElement ) { 
                    throw new XmlException( Res.Xml_InvalidNodeType, reader.NodeType.ToString(), reader as IXmlLineInfo );
                } 
                // move off end element 
                reader.Read();
                return false; 
            }
            state = State.InReadElementContent;
            isEnd = false;
            return true; 
        }
 
        private void InitBase64Decoder() { 
            if ( base64Decoder == null ) {
                base64Decoder = new Base64Decoder(); 
            }
            else {
                base64Decoder.Reset();
            } 
            decoder = base64Decoder;
        } 
 
        private void InitBinHexDecoder() {
            if ( binHexDecoder == null ) { 
                binHexDecoder = new BinHexDecoder();
            }
            else {
                binHexDecoder.Reset(); 
            }
            decoder = binHexDecoder; 
        } 

        private int ReadContentAsBinary( byte[] buffer, int index, int count ) { 
            Debug.Assert( decoder != null );

            if ( isEnd ) {
                Reset(); 
                return 0;
            } 
            decoder.SetNextOutputBuffer( buffer, index, count ); 

            for (;;) { 
                // use streaming ReadValueChunk if the reader supports it
                if ( canReadValueChunk ) {
                    for (;;) {
                        if ( valueOffset < valueChunkLength ) { 
                            int decodedCharsCount = decoder.Decode( valueChunk, valueOffset, valueChunkLength - valueOffset );
                            valueOffset += decodedCharsCount; 
                        } 
                        if ( decoder.IsFull ) {
                            return decoder.DecodedCount; 
                        }
                        Debug.Assert( valueOffset == valueChunkLength );
                        if ( ( valueChunkLength = reader.ReadValueChunk( valueChunk, 0, ChunkSize ) ) == 0 ) {
                            break; 
                        }
                        valueOffset = 0; 
                    } 
                }
                else { 
                    // read what is reader.Value
                    string value = reader.Value;
                    int decodedCharsCount = decoder.Decode( value, valueOffset, value.Length - valueOffset );
                    valueOffset += decodedCharsCount; 

                    if ( decoder.IsFull ) { 
                        return decoder.DecodedCount; 
                    }
                } 

                valueOffset = 0;

                // move to next textual node in the element content; throw on sub elements 
                if ( !MoveToNextContentNode( true ) ) {
                    isEnd = true; 
                    return decoder.DecodedCount; 
                }
            } 
        }

        private int ReadElementContentAsBinary( byte[] buffer, int index, int count ) {
            if ( count == 0 ) { 
                return 0;
            } 
            // read binary 
            int decoded = ReadContentAsBinary( buffer, index, count );
            if ( decoded > 0 ) { 
                return decoded;
            }

            // if 0 bytes returned check if we are on a closing EndElement, throw exception if not 
            if ( reader.NodeType != XmlNodeType.EndElement ) {
                throw new XmlException( Res.Xml_InvalidNodeType, reader.NodeType.ToString(), reader as IXmlLineInfo ); 
            } 

            // move off the EndElement 
            reader.Read();
            state = State.None;
            return 0;
        } 

        bool MoveToNextContentNode( bool moveIfOnContentNode ) { 
            do { 
                switch ( reader.NodeType ) {
                    case XmlNodeType.Attribute: 
                        return !moveIfOnContentNode;
                    case XmlNodeType.Text:
                    case XmlNodeType.Whitespace:
                    case XmlNodeType.SignificantWhitespace: 
                    case XmlNodeType.CDATA:
                        if ( !moveIfOnContentNode ) { 
                            return true; 
                        }
                        break; 
                    case XmlNodeType.ProcessingInstruction:
                    case XmlNodeType.Comment:
                    case XmlNodeType.EndEntity:
                        // skip comments, pis and end entity nodes 
                        break;
                    case XmlNodeType.EntityReference: 
                        if ( reader.CanResolveEntity ) { 
                            reader.ResolveEntity();
                            break; 
                        }
                        goto default;
                    default:
                        return false; 
                }
                moveIfOnContentNode = false; 
            } while ( reader.Read() ); 
            return false;
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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ReadContentAsBinaryHelper.cs source code in C# .NET

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