1 /*

     2 * Copyright (c) 2004-2008 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description: 

    15 *

    16 */

    17 

    18 using System;

    19 using System.IO;

    20 using System.Text;

    21 using System.Collections;

    22 using System.Diagnostics;

    23 

    24 namespace SymBuildParsingLib

    25 {

    26 	#region Exceptions

    27 	public class SymParserStreamExceptionInvalidRewindAmount : Exception

    28 	{

    29 		public SymParserStreamExceptionInvalidRewindAmount( string aMessage )

    30 			: base( aMessage )

    31 		{

    32 		}

    33 	}

    34 	#endregion

    35 

    36 	public class SymStream

    37 	{

    38 		#region Constructors & destructor

    39 		public SymStream( string aFileName )

    40 		{

    41 			iFileName = aFileName;

    42 			iFileStream = new FileStream( aFileName, System.IO.FileMode.Open );

    43 			iStream = new StreamReader( iFileStream );

    44 			iFileData = new Stack( 1024 * 20 );

    45 		}

    46 		#endregion

    47 

    48 		#region API

    49 		public char PeekChar()

    50 		{

    51 			Debug.Assert( !EOF );

    52 			//

    53 			char ret = (char) iStream.Peek();

    54 			//

    55 			if	( iPushedBackCharacters.Count > 0 )

    56 			{

    57 				ret = (char) iPushedBackCharacters.Peek();

    58 			}

    59 			return ret;

    60 		}

    61 

    62 		public char ReadChar()

    63 		{

    64 			Debug.Assert( !EOF );

    65 			//

    66 			char ret;

    67 			//

    68 			if	( iPushedBackCharacters.Count > 0 )

    69 			{

    70 				ret = (char) iPushedBackCharacters.Pop();

    71 			}

    72 			else

    73 			{

    74 				ret = (char) iStream.Read();

    75 			}

    76 			//

    77 			iFileData.Push( ret );

    78 			++iPosition;

    79 			//

    80 			return ret;

    81 		}

    82 

    83 		public void RewindChar()

    84 		{

    85 			RewindChars( 1 );

    86 		}

    87 

    88 		public void RewindChars( int aRewindCount )

    89 		{

    90 			long newPos = Position - aRewindCount;

    91 			if	( aRewindCount < 0 )

    92 				throw new SymParserStreamExceptionInvalidRewindAmount( "Rewind specifier must be >= 0" );

    93 			else if ( newPos < 0 || newPos >= Size ) 

    94 				throw new SymParserStreamExceptionInvalidRewindAmount( "Rewind specifier takes stream position beyond scope of file" );

    95 

    96 			for( int i=0; i<aRewindCount; i++ )

    97 			{

    98 				char character = (char) iFileData.Pop();

    99 				iPushedBackCharacters.Push( character );

   100 			}

   101 

   102 			iPosition -= aRewindCount;

   103 		}

   104 		#endregion

   105 

   106 		#region Properties

   107 		public string FileName

   108 		{

   109 			get { return iFileName; }

   110 		}

   111 

   112 		public long Position

   113 		{

   114 			get { return iPosition; }

   115 		}

   116 

   117 		public long Size

   118 		{

   119 			get { return iStream.BaseStream.Length; }

   120 		}

   121 

   122 		public bool EOF

   123 		{

   124 			get

   125 			{

   126 				long fileSize = Size;

   127 				bool atEnd = ( Position >= fileSize );

   128 				return atEnd;

   129 			}

   130 		}

   131 		#endregion

   132 

   133 		#region Constants

   134 		private const int KStreamEOF = -1;

   135 		#endregion

   136 

   137 		#region Data members

   138 		private readonly string iFileName;

   139 		private StreamReader iStream;

   140 		private FileStream iFileStream;

   141 		private Stack iPushedBackCharacters = new Stack( 1024 );

   142 		private Stack iFileData;

   143 		private long iPosition;

   144 		#endregion

   145 	}

   146 }