Code Coverage Statistics for Source File
c:\Tools\SD3\src\Libraries\ICSharpCode.TextEditor\Project\Src\Util\FileReader.cs
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Branch Coverage
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// <file> |
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// <copyright see="prj:///doc/copyright.txt"/> |
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// <license see="prj:///doc/license.txt"/> |
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// <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/> |
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// <version>$Revision: 2682 $</version> |
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// </file> |
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using System; |
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using System.IO; |
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using System.Text; |
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namespace ICSharpCode.TextEditor.Util |
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{ |
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/// <summary> |
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/// Class that can open text files with auto-detection of the encoding. |
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/// </summary> |
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public static class FileReader |
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{ |
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public static bool IsUnicode(Encoding encoding) |
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{ |
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int codepage = encoding.CodePage; |
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// return true if codepage is any UTF codepage |
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return codepage == 65001 || codepage == 65000 || codepage == 1200 || codepage == 1201; |
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} |
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public static string ReadFileContent(Stream fs, ref Encoding encoding) |
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{ |
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using (StreamReader reader = OpenStream(fs, encoding)) { |
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reader.Peek(); |
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encoding = reader.CurrentEncoding; |
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return reader.ReadToEnd(); |
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} |
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} |
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public static string ReadFileContent(string fileName, Encoding encoding) |
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{ |
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using (FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) { |
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return ReadFileContent(fs, ref encoding); |
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} |
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} |
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public static StreamReader OpenStream(Stream fs, Encoding defaultEncoding) |
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{ |
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if (fs == null) |
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throw new ArgumentNullException("fs"); |
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if (fs.Length >= 2) { |
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// the autodetection of StreamReader is not capable of detecting the difference |
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// between ISO-8859-1 and UTF-8 without BOM. |
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int firstByte = fs.ReadByte(); |
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int secondByte = fs.ReadByte(); |
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switch ((firstByte << 8) | secondByte) { |
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case 0x0000: // either UTF-32 Big Endian or a binary file; use StreamReader |
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case 0xfffe: // Unicode BOM (UTF-16 LE or UTF-32 LE) |
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case 0xfeff: // UTF-16 BE BOM |
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case 0xefbb: // start of UTF-8 BOM |
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// StreamReader autodetection works |
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fs.Position = 0; |
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return new StreamReader(fs); |
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default: |
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return AutoDetect(fs, (byte)firstByte, (byte)secondByte, defaultEncoding); |
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} |
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} else { |
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if (defaultEncoding != null) { |
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return new StreamReader(fs, defaultEncoding); |
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} else { |
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return new StreamReader(fs); |
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} |
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} |
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} |
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static StreamReader AutoDetect(Stream fs, byte firstByte, byte secondByte, Encoding defaultEncoding) |
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{ |
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int max = (int)Math.Min(fs.Length, 500000); // look at max. 500 KB |
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const int ASCII = 0; |
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const int Error = 1; |
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const int UTF8 = 2; |
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const int UTF8Sequence = 3; |
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int state = ASCII; |
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int sequenceLength = 0; |
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byte b; |
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for (int i = 0; i < max; i++) { |
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if (i == 0) { |
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b = firstByte; |
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} else if (i == 1) { |
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b = secondByte; |
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} else { |
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b = (byte)fs.ReadByte(); |
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} |
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if (b < 0x80) { |
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// normal ASCII character |
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if (state == UTF8Sequence) { |
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state = Error; |
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break; |
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} |
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} else if (b < 0xc0) { |
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// 10xxxxxx : continues UTF8 byte sequence |
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if (state == UTF8Sequence) { |
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--sequenceLength; |
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if (sequenceLength < 0) { |
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state = Error; |
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break; |
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} else if (sequenceLength == 0) { |
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state = UTF8; |
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} |
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} else { |
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state = Error; |
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break; |
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} |
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} else if (b >= 0xc2 && b < 0xf5) { |
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// beginning of byte sequence |
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if (state == UTF8 || state == ASCII) { |
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state = UTF8Sequence; |
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if (b < 0xe0) { |
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sequenceLength = 1; // one more byte following |
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} else if (b < 0xf0) { |
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sequenceLength = 2; // two more bytes following |
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} else { |
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sequenceLength = 3; // three more bytes following |
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} |
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} else { |
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state = Error; |
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break; |
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} |
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} else { |
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// 0xc0, 0xc1, 0xf5 to 0xff are invalid in UTF-8 (see RFC 3629) |
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state = Error; |
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break; |
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} |
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} |
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fs.Position = 0; |
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switch (state) { |
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case ASCII: |
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case Error: |
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// when the file seems to be ASCII or non-UTF8, |
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// we read it using the user-specified encoding so it is saved again |
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// using that encoding. |
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if (IsUnicode(defaultEncoding)) { |
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// the file is not Unicode, so don't read it using Unicode even if the |
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// user has choosen Unicode as the default encoding. |
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// If we don't do this, SD will end up always adding a Byte Order Mark |
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// to ASCII files. |
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defaultEncoding = Encoding.Default; // use system encoding instead |
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} |
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return new StreamReader(fs, defaultEncoding); |
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default: |
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return new StreamReader(fs); |
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} |
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} |
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} |
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} |