/// <summary>
/// Detects the best <see cref="Encoding"/> to use to convert the data in the supplied stream to Unicode, and returns it.
/// </summary>
/// <param name="stream">The stream to detect the character encoding for.</param>
/// <returns>The best <see cref="Encoding"/> object to be used to decode text from <paramref name="stream"/>
/// into Unicode, or <c>null</c> if the best encoding can't be detected.</returns>
/// <remarks>See <a href="http://code.logos.com/blog/2010/05/detecting_the_character_encoding_of_a_file.html">Detecting the Character Encoding of a File</a>.</remarks>
public static Encoding DetectBestEncoding(Stream stream)
{
// check parameter validity
if (stream == null)
{
throw new ArgumentNullException("stream");
}
if (!stream.CanRead)
{
throw new NotSupportedException("'stream' must be readable.");
}
if (!stream.CanSeek)
{
throw new NotSupportedException("'stream' must be seekable.");
}
// the encoding that was detected, or null on failure
Encoding encoding = null;
// MLang will move the stream pointer; remember its original position
long position = stream.Position;
// allocate a number of DetectEncodingInfo structures for MLang to fill in
DetectEncodingInfo[] infos = new DetectEncodingInfo[8];
int infoCount = infos.Length;
// allow MLang to seek to the "beginning" (i.e., current position) of the stream by rebasing it
using (RebasedStream rebased = new RebasedStream(stream))
{
try
{
// try to create MLang object
IMultiLanguage2 multiLanguage = (IMultiLanguage2) new MultiLanguage();
// wrap input stream with an IStream
ManagedIStream istream = new ManagedIStream(rebased);
// detect the code page
int hresult = multiLanguage.DetectCodepageInIStream(MultiLanguageDetectCodePage.None, 0, istream, ref infos[0], ref infoCount);
GC.KeepAlive(istream);
if (infoCount > 0 && (hresult == Win32.S_OK || hresult == Win32.S_FALSE))
{
// take the best code page that was found
int nCodePage = (int)infos.Take(infoCount).OrderByDescending(i => i.nConfidence).Select(i => i.nCodePage).FirstOrDefault();
encoding = Encoding.GetEncoding(nCodePage);
}
}
catch (COMException)
{
// failure
}
}
// reset the stream back to its input position for the caller
stream.Position = position;
// return detected encoding (or null for failure)
return(encoding);
}
/// <summary>
/// Detects the best <see cref="Encoding"/> to use to convert the data in the supplied stream to Unicode, and returns it.
/// </summary>
/// <param name="stream">The stream to detect the character encoding for.</param>
/// <returns>The best <see cref="Encoding"/> object to be used to decode text from <paramref name="stream"/>
/// into Unicode, or <c>null</c> if the best encoding can't be detected.</returns>
/// <remarks>See <a href="http://code.logos.com/blog/2010/05/detecting_the_character_encoding_of_a_file.html">Detecting the Character Encoding of a File</a>.</remarks>
public static Encoding DetectBestEncoding(Stream stream)
{
// check parameter validity
if (stream == null)
throw new ArgumentNullException("stream");
if (!stream.CanRead)
throw new NotSupportedException("'stream' must be readable.");
if (!stream.CanSeek)
throw new NotSupportedException("'stream' must be seekable.");
// the encoding that was detected, or null on failure
Encoding encoding = null;
// MLang will move the stream pointer; remember its original position
long position = stream.Position;
// allocate a number of DetectEncodingInfo structures for MLang to fill in
DetectEncodingInfo[] infos = new DetectEncodingInfo[8];
int infoCount = infos.Length;
// allow MLang to seek to the "beginning" (i.e., current position) of the stream by rebasing it
using (RebasedStream rebased = new RebasedStream(stream))
{
try
{
// try to create MLang object
IMultiLanguage2 multiLanguage = (IMultiLanguage2) new MultiLanguage();
// wrap input stream with an IStream
ManagedIStream istream = new ManagedIStream(rebased);
// detect the code page
int hresult = multiLanguage.DetectCodepageInIStream(MultiLanguageDetectCodePage.None, 0, istream, ref infos[0], ref infoCount);
GC.KeepAlive(istream);
if (infoCount > 0 && (hresult == Win32.S_OK || hresult == Win32.S_FALSE))
{
// take the best code page that was found
int nCodePage = (int) infos.Take(infoCount).OrderByDescending(i => i.nConfidence).Select(i => i.nCodePage).FirstOrDefault();
encoding = Encoding.GetEncoding(nCodePage);
}
}
catch (COMException)
{
// failure
}
}
// reset the stream back to its input position for the caller
stream.Position = position;
// return detected encoding (or null for failure)
return encoding;
}
/// <summary>
/// Returns up to maxEncodings codepages that are assumed to be apropriate
/// </summary>
/// <param name="input">array containing the raw data</param>
/// <param name="maxEncodings">maxiumum number of encodings to detect</param>
/// <returns>an array of Encoding with assumed encodings</returns>
public static Encoding[] DetectInputCodepages(byte[] input, int maxEncodings)
{
if (maxEncodings < 1)
throw new ArgumentOutOfRangeException("maxEncodings", "at least one encoding must be returned");
if (input == null)
throw new ArgumentNullException("input");
// empty strings can always be encoded as ASCII
if (input.Length == 0)
return new Encoding[] { Encoding.ASCII };
// expand the string to be at least 256 bytes
if (input.Length < 256)
{
byte[] newInput = new byte[256];
int steps = 256 / input.Length;
for (int i = 0; i < steps; i++)
Array.Copy(input, 0, newInput, input.Length * i, input.Length);
int rest = 256 % input.Length;
if (rest > 0)
Array.Copy(input, 0, newInput, steps * input.Length, rest);
input = newInput;
}
List<Encoding> result = new List<Encoding>();
// get the IMultiLanguage" interface
IMultiLanguage2 multilang2 = new CMultiLanguageClass();
if (multilang2 == null)
throw new COMException("Failed to get IMultilang2");
try
{
DetectEncodingInfo[] detectedEncdings = new DetectEncodingInfo[maxEncodings];
int scores = detectedEncdings.Length;
int srcLen = input.Length;
// setup options (none)
const MLDETECTCP options = MLDETECTCP.MLDETECTCP_NONE;
// finally... call to DetectInputCodepage
multilang2.DetectInputCodepage(options, 0,
ref input[0], ref srcLen, ref detectedEncdings[0], ref scores);
// get result
if (scores > 0)
{
for (int i = 0; i < scores; i++)
{
// add the result
result.Add(Encoding.GetEncoding((int)detectedEncdings[i].nCodePage));
}
}
}
finally
{
Marshal.FinalReleaseComObject(multilang2);
}
// nothing found
return result.ToArray();
}
/// <summary>
/// Rerurns up to maxEncodings codpages that are assumed to be apropriate
/// </summary>
/// <param name="input">array containing the raw data</param>
/// <param name="maxEncodings">maxiumum number of encodings to detect</param>
/// <returns>an array of Encoding with assumed encodings</returns>
public static Encoding[] DetectInputCodepages(byte[] input, int maxEncodings)
{
if (maxEncodings < 1)
{
throw new ArgumentOutOfRangeException("maxEncodings", "at least one encoding must be returned");
}
if (input == null)
{
throw new ArgumentNullException("input");
}
// empty strings can always be encoded as ASCII
if (input.Length == 0)
{
return new Encoding[] { Encoding.ASCII };
}
// expand the string to be at least 256 bytes
if (input.Length < 256)
{
byte[] newInput = new byte[256];
int steps = 256 / input.Length;
for (int i = 0; i < steps; i++)
{
Array.Copy(input, 0, newInput, input.Length * i, input.Length);
}
int rest = 256 % input.Length;
if (rest > 0)
{
Array.Copy(input, 0, newInput, steps * input.Length, rest);
}
input = newInput;
}
List<Encoding> result = new List<Encoding>();
// get the IMultiLanguage" interface
IMultiLanguage2 multilang2 = new CMultiLanguageClass();
if (multilang2 == null)
{
throw new COMException("Failed to get IMultilang2");
}
try
{
DetectEncodingInfo[] detectedEncdings = new DetectEncodingInfo[maxEncodings];
int scores = detectedEncdings.Length;
int srcLen = input.Length;
// setup options (none)
const Mldetectcp options = Mldetectcp.MldetectcpNone;
// finally... call to DetectInputCodepage
multilang2.DetectInputCodepage(options, 0,
ref input[0], ref srcLen, ref detectedEncdings[0], ref scores);
// get result
if (scores > 0)
{
for (int i = 0; i < scores; i++)
{
// add the result
result.Add(Encoding.GetEncoding((int)detectedEncdings[i].nCodePage));
}
}
}
finally
{
Marshal.FinalReleaseComObject(multilang2);
}
// nothing found
return result.ToArray();
}
public static Encoding[] GetEncodings(byte[] input, int maxEncodings)
{
if (input.IsNullOrEmpty())
{
return(new[]
{
Default
});
}
if (maxEncodings < 1)
{
maxEncodings = 1;
}
// expand the string to be at least 256 bytes
if (input.Length < 256)
{
byte[] newInput = new byte[256];
int steps = 256 / input.Length;
for (int i = 0; i < steps; i++)
{
Array.Copy(input, 0, newInput, input.Length * i, input.Length);
}
int rest = 256 % input.Length;
if (rest > 0)
{
Array.Copy(input, 0, newInput, steps * input.Length, rest);
}
input = newInput;
}
List <Encoding> result = new List <Encoding>();
// get the IMultiLanguage" interface
IMultiLanguage2 multiLang2 = new CMultiLanguageClass();
if (multiLang2 == null)
{
throw new COMException("Failed to get " + nameof(IMultiLanguage2));
}
try
{
DetectEncodingInfo[] detectedEncodings = new DetectEncodingInfo[maxEncodings];
int scores = detectedEncodings.Length;
int srcLen = input.Length;
// finally... call to DetectInputCodepage
multiLang2.DetectInputCodepage(MLDETECTCP.MLDETECTCP_NONE, 0, ref input[0], ref srcLen, ref detectedEncodings[0], ref scores);
// get result
if (scores > 0)
{
for (int i = 0; i < scores; i++)
{
result.Add(Encoding.GetEncoding((int)detectedEncodings[i].nCodePage));
}
}
}
finally
{
Marshal.FinalReleaseComObject(multiLang2);
}
return(result.ToArray());
}
