ANTLRFileStream.cs revision 324c4644fee44b9898524c09511bd33c3f12e2df 
1/*
2[The "BSD licence"]
3Copyright (c) 2005-2007 Kunle Odutola
4All rights reserved.
5
6Redistribution and use in source and binary forms, with or without
7modification, are permitted provided that the following conditions
8are met:
91. Redistributions of source code MUST RETAIN the above copyright
10   notice, this list of conditions and the following disclaimer.
112. Redistributions in binary form MUST REPRODUCE the above copyright
12   notice, this list of conditions and the following disclaimer in
13   the documentation and/or other materials provided with the
14   distribution.
153. The name of the author may not be used to endorse or promote products
16   derived from this software without specific prior WRITTEN permission.
174. Unless explicitly state otherwise, any contribution intentionally
18   submitted for inclusion in this work to the copyright owner or licensor
19   shall be under the terms and conditions of this license, without any
20   additional terms or conditions.
21
22THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32*/
33
34
35namespace Antlr.Runtime
36{
37	using System;
38	using StreamReader	= System.IO.StreamReader;
39	using FileInfo		= System.IO.FileInfo;
40	using Encoding		= System.Text.Encoding;
41
42	/// <summary>
43	/// A character stream - an <see cref="ICharStream"/> - that loads
44	/// and caches the contents of it's underlying file fully during
45	/// object construction
46	/// </summary>
47	/// <remarks>
48	/// This looks very much like an ANTLReaderStream or an ANTLRInputStream
49	/// but, it is a special case. Since we know the exact size of the file to
50	/// load, we can avoid lots of data copying and buffer resizing.
51	/// </remarks>
52	public class ANTLRFileStream : ANTLRStringStream
53	{
54		#region Constructors
55
56		/// <summary>
57		/// Initializes a new instance of the ANTLRFileStream class
58		/// </summary>
59		protected ANTLRFileStream()
60		{
61		}
62
63		/// <summary>
64		/// Initializes a new instance of the ANTLRFileStream class for the
65		/// specified file name
66		/// </summary>
67		public ANTLRFileStream(string fileName) :
68			this(fileName, Encoding.Default)
69		{
70		}
71
72		/// <summary>
73		/// Initializes a new instance of the ANTLRFileStream class for the
74		/// specified file name and encoding
75		/// </summary>
76		public ANTLRFileStream(string fileName, Encoding encoding)
77		{
78			this.fileName = fileName;
79			Load(fileName, encoding);
80		}
81
82		/// <summary>
83		/// Gets the file name of this ANTLRFileStream underlying file
84		/// </summary>
85		override public string SourceName
86		{
87			get { return fileName; }
88		}
89
90		#endregion
91
92
93		#region Public API
94
95		/// <summary>
96		/// Loads and buffers the specified file to be used as this
97		/// ANTLRFileStream's source
98		/// </summary>
99		/// <param name="fileName">File to load</param>
100		/// <param name="encoding">Encoding to apply to file</param>
101		public virtual void Load(string fileName, Encoding encoding)
102		{
103			if (fileName == null)
104				return;
105
106			StreamReader fr = null;
107			try
108			{
109				FileInfo f = new FileInfo(fileName);
110				int filelen = (int)GetFileLength(f);
111				data = new char[filelen];
112				if (encoding != null)
113					fr = new StreamReader(fileName, encoding);
114				else
115					fr = new StreamReader(fileName, Encoding.Default);
116				n = fr.Read((Char[])data, 0, data.Length);
117			}
118			finally
119			{
120				if (fr != null)
121				{
122					fr.Close();
123				}
124			}
125		}
126
127		#endregion
128
129
130		#region Data Members
131
132		/// <summary>Fully qualified name of the stream's underlying file</summary>
133		protected string fileName;
134
135		#endregion
136
137
138		#region Private Members
139
140		private long GetFileLength(FileInfo file)
141		{
142			if (file.Exists)
143				return file.Length;
144			else
145				return 0;
146		}
147
148		#endregion
149	}
150}