Exemplo n.º 1
0
        /// <summary>
        /// Decode a Qap1-encoded Sexp
        /// </summary>
        /// <param name="data">The byte stream in which the Sexp is encoded</param>
        /// <param name="start">At which index of data does the Sexp begin?</param>
        /// <returns>The decoded Sexp.</returns>
        private static Sexp DecodeSexp(byte[] data, ref long start)
        {
            // pull sexp type
            byte xt = data[start];

            // calculate length of payload
            var lengthBuf = new byte[8];

            Array.Copy(data, start + 1, lengthBuf, 0, 3);
            start += 4;
            if ((xt & XtLarge) == XtLarge)
            {
                Array.Copy(data, start, lengthBuf, 3, 4);
                start += 4;
                xt    -= XtLarge;
            }
            var length = ( long )BitConverter.ToUInt64(lengthBuf, 0);

            // has attributes?  process first
            SexpTaggedList attrs = null;

            if ((xt & XtHasAttr) == XtHasAttr)
            {
                xt -= XtHasAttr;
                long oldstart = start;
                attrs   = ( SexpTaggedList )DecodeSexp(data, ref start);
                length -= start - oldstart;
            }

            long end = start + length;
            Sexp result;

            switch (xt)
            {
            case XtNull:
            {
                if (length != 0)
                {
                    throw new RserveException("Attempting to decode an SexpNull, but it is followed by data when it shouldn't be.");
                }
                result = new SexpNull();
            }
            break;

            case XtSymName:
            {
                // keep all characters up to the first null
                var symnNamBuf = new byte[length];
                Array.Copy(data, start, symnNamBuf, 0, length);
                string res = Encoding.UTF8.GetString(symnNamBuf);
                result = new SexpSymname(res.Split('\x00')[0]);
            }
            break;

            case XtArrayInt:
            {
                var res    = new int[length / 4];
                var intBuf = new byte[4];
                for (long i = 0; i < length; i += 4)
                {
                    Array.Copy(data, start + i, intBuf, 0, 4);
                    res[i / 4] = BitConverter.ToInt32(intBuf, 0);
                }

                // is date or just an integer?
                if ((attrs != null) && (attrs.ContainsKey("class") && attrs["class"].AsStrings.Contains("Date")))
                {
                    result = new SexpArrayDate(res);
                }
                else
                {
                    result = new SexpArrayInt(res);
                }
            }
            break;

            case XtArrayBool:
            {
                if (length < 4)
                {
                    throw new RserveException("Decoding an SexpArrayBool where data doesn't seem to contain a data length field.");
                }
                var boolLengthBuf = new byte[4];
                Array.Copy(data, start, boolLengthBuf, 0, 4);
                var datalength = BitConverter.ToInt32(boolLengthBuf, 0);
                if (datalength > length - 4)
                {
                    throw new RserveException("Decoding an SexpArrayBool where transmitted data field too short for number of entries.");
                }

                var res = new bool?[datalength];
                for (int i = 0; i < datalength; i++)
                {
                    // R logical is false if 0, true if 1, and NA if 2
                    switch (data[start + i + 4])
                    {
                    case 0:
                        res[i] = false;
                        break;

                    case 1:
                        res[i] = true;
                        break;

                    case 2:
                        res[i] = null;
                        break;

                    default:
                        throw new RserveException("Decoding an SexpArrayBool and found an element in the array that is not an R bool: " + data[start + i + 4]);
                    }
                }

                result = new SexpArrayBool(res);
            }
            break;

            case XtArrayDouble:
            {
                var res       = new double[length / 8];
                var doubleBuf = new byte[8];
                for (long i = 0; i < length; i += 8)
                {
                    Array.Copy(data, start + i, doubleBuf, 0, 8);
                    res[i / 8] = BitConverter.ToDouble(doubleBuf, 0);
                }

                // is date or just a double?
                if ((attrs != null) && (attrs.ContainsKey("class") && attrs["class"].AsStrings.Contains("Date")))
                {
                    result = new SexpArrayDate(res.Select(Convert.ToInt32));
                }
                else
                {
                    result = new SexpArrayDouble(res);
                }
            }
            break;

            case XtArrayString:
            {
                var  res = new List <string>();
                long i   = 0;
                for (long j = 0; j < length; j++)
                {
                    if (data[start + j] != 0)
                    {
                        continue;
                    }

                    if ((j == i + 1) && (data[start + i] == 255))
                    {
                        res.Add(null);
                    }
                    else
                    {
                        if (data[start + i] == 255)
                        {
                            i++;
                        }

                        var stringBuf = new byte[j - i];
                        Array.Copy(data, start + i, stringBuf, 0, j - i);
                        res.Add(Encoding.UTF8.GetString(stringBuf));
                    }
                    i = j + 1;
                }

                result = new SexpArrayString(res);
            }
            break;

            case XtListNoTag:
            case XtLangNoTag:
            case XtVector:
                result = new SexpList();
                while (start < end)
                {
                    result.Add(DecodeSexp(data, ref start));
                }
                break;

            case XtLangTag:
            case XtListTag:
                result = new SexpTaggedList();
                while (start < end)
                {
                    Sexp val = DecodeSexp(data, ref start);
                    Sexp key = DecodeSexp(data, ref start);
                    result.Add(key.IsNull ? String.Empty : key.AsString, val);
                }

                break;

            case XtRaw:
            {
                var d = new byte[length];
                Array.Copy(data, start, d, 0, length);
                result = new SexpQap1Raw(xt, d);
            }
            break;

            default:
                throw new RserveException("Cannot decode an Sexp because the type is not recognized: " + xt);
            }

            if (start > end)
            {
                throw new RserveException("When decoding an Sexp, more data consumed than provided.");
            }

            start = end;
            if (attrs != null)
            {
                foreach (var a in attrs.AsSexpDictionary)
                {
                    result.Attributes.Add(a.Key, a.Value);
                }
            }

            return(result);
        }
Exemplo n.º 2
0
        /// <summary>
        /// Decode a Qap1-encoded Sexp
        /// </summary>
        /// <param name="data">The byte stream in which the Sexp is encoded</param>
        /// <param name="start">At which index of data does the Sexp begin?</param>
        /// <returns>The decoded Sexp.</returns>
        private static Sexp DecodeSexp( byte[] data , ref long start )
        {
            // pull sexp type
            byte xt = data[ start ];

            // calculate length of payload
            var lengthBuf = new byte[ 8 ];
            Array.Copy( data , start + 1 , lengthBuf , 0 , 3 );
            start += 4;
            if ( ( xt & XtLarge ) == XtLarge )
            {
                Array.Copy( data , start , lengthBuf , 3 , 4 );
                start += 4;
                xt -= XtLarge;
            }
            var length = ( long )BitConverter.ToUInt64( lengthBuf , 0 );

            // has attributes?  process first
            SexpTaggedList attrs = null;
            if ( ( xt & XtHasAttr ) == XtHasAttr )
            {
                xt -= XtHasAttr;
                long oldstart = start;
                attrs = ( SexpTaggedList )DecodeSexp( data , ref start );
                length -= start - oldstart;
            }

            long end = start + length;
            Sexp result;

            switch ( xt )
            {
                case XtNull:
                    {
                        if ( length != 0 )
                        {
                            throw new RserveException( "Attempting to decode an SexpNull, but it is followed by data when it shouldn't be." );
                        }
                        result = new SexpNull();
                    }
                    break;
                case XtSymName:
                    {
                        // keep all characters up to the first null
                        var symnNamBuf = new byte[ length ];
                        Array.Copy( data , start , symnNamBuf , 0 , length );
                        string res = Encoding.UTF8.GetString( symnNamBuf );
                        result = new SexpSymname( res.Split( '\x00' )[ 0 ] );
                    }
                    break;
                case XtArrayInt:
                    {
                        var res = new int[ length / 4 ];
                        var intBuf = new byte[ 4 ];
                        for ( long i = 0 ; i < length ; i += 4 )
                        {
                            Array.Copy( data , start + i , intBuf , 0 , 4 );
                            res[ i / 4 ] = BitConverter.ToInt32( intBuf , 0 );
                        }

                        // is date or just an integer?
                        if ( ( attrs != null ) && ( attrs.ContainsKey( "class" ) && attrs[ "class" ].AsStrings.Contains( "Date" ) ) )
                        {
                            result = new SexpArrayDate( res );
                        }
                        else
                        {
                            result = new SexpArrayInt( res );
                        }
                    }
                    break;
                case XtArrayBool:
                    {
                        if ( length < 4 )
                        {
                            throw new RserveException( "Decoding an SexpArrayBool where data doesn't seem to contain a data length field." );
                        }
                        var boolLengthBuf = new byte[ 4 ];
                        Array.Copy( data , start , boolLengthBuf , 0 , 4 );
                        var datalength = BitConverter.ToInt32( boolLengthBuf , 0 );
                        if ( datalength > length - 4 )
                        {
                            throw new RserveException( "Decoding an SexpArrayBool where transmitted data field too short for number of entries." );
                        }

                        var res = new bool?[ datalength ];
                        for ( int i = 0 ; i < datalength ; i++ )
                        {
                            // R logical is false if 0, true if 1, and NA if 2
                            switch ( data[ start + i + 4 ] )
                            {
                                case 0:
                                    res[ i ] = false;
                                    break;
                                case 1:
                                    res[ i ] = true;
                                    break;
                                case 2:
                                    res[ i ] = null;
                                    break;
                                default:
                                    throw new RserveException( "Decoding an SexpArrayBool and found an element in the array that is not an R bool: " + data[ start + i + 4 ] );
                            }
                        }

                        result = new SexpArrayBool( res );
                    }
                    break;
                case XtArrayDouble:
                    {
                        var res = new double[ length / 8 ];
                        var doubleBuf = new byte[ 8 ];
                        for ( long i = 0 ; i < length ; i += 8 )
                        {
                            Array.Copy( data , start + i , doubleBuf , 0 , 8 );
                            res[ i / 8 ] = BitConverter.ToDouble( doubleBuf , 0 );
                        }

                        // is date or just a double?
                        if ( ( attrs != null ) && ( attrs.ContainsKey( "class" ) && attrs[ "class" ].AsStrings.Contains( "Date" ) ) )
                        {
                            result = new SexpArrayDate( res.Select( Convert.ToInt32 ) );
                        }
                        else
                        {
                            result = new SexpArrayDouble( res );
                        }
                    }
                    break;
                case XtArrayString:
                    {
                        var res = new List<string>();
                        long i = 0;
                        for ( long j = 0 ; j < length ; j++ )
                        {
                            if ( data[ start + j ] != 0 )
                            {
                                continue;
                            }

                            if ( ( j == i + 1 ) && ( data[ start + i ] == 255 ) )
                            {
                                res.Add( null );
                            }
                            else
                            {
                                if ( data[ start + i ] == 255 )
                                {
                                    i++;
                                }

                                var stringBuf = new byte[ j - i ];
                                Array.Copy( data , start + i , stringBuf , 0 , j - i );
                                res.Add( Encoding.UTF8.GetString( stringBuf ) );
                            }
                            i = j + 1;
                        }

                        result = new SexpArrayString( res );
                    }
                    break;
                case XtListNoTag:
                case XtLangNoTag:
                case XtVector:
                    result = new SexpList();
                    while ( start < end )
                    {
                        result.Add( DecodeSexp( data , ref start ) );
                    }
                    break;
                case XtLangTag:
                case XtListTag:
                    result = new SexpTaggedList();
                    while ( start < end )
                    {
                        Sexp val = DecodeSexp( data , ref start );
                        Sexp key = DecodeSexp( data , ref start );
                        result.Add( key.IsNull ? String.Empty : key.AsString , val );
                    }

                    break;
                case XtRaw:
                    {
                        var d = new byte[ length ];
                        Array.Copy( data , start , d , 0 , length );
                        result = new SexpQap1Raw( xt , d );
                    }
                    break;
                default:
                    throw new RserveException( "Cannot decode an Sexp because the type is not recognized: " + xt );
            }

            if ( start > end )
            {
                throw new RserveException( "When decoding an Sexp, more data consumed than provided." );
            }

            start = end;
            if ( attrs != null )
            {
                foreach ( var a in attrs.AsSexpDictionary )
                {
                    result.Attributes.Add( a.Key , a.Value );
                }
            }

            return result;
        }