/// <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("at least one encoding must be returend", "maxEncodings");
if (input == null)
throw new ArgumentNullException("input");
// empty strings can always be encoded as ASCII
if (input.Length == 0)
return new[] {Encoding.ASCII};
// expand the string to be at least 256 bytes
if (input.Length < 256)
{
var newInput = new byte[256];
var steps = 256/input.Length;
for (var i = 0; i < steps; i++)
Array.Copy(input, 0, newInput, input.Length*i, input.Length);
var rest = 256%input.Length;
if (rest > 0)
Array.Copy(input, 0, newInput, steps*input.Length, rest);
input = newInput;
}
var result = new List<Encoding>();
// get the IMultiLanguage" interface
IMultiLanguage2 multilang2 = new CMultiLanguageClass();
if (multilang2 == null)
throw new COMException("Failed to get IMultilang2");
try
{
var detectedEncdings = new DetectEncodingInfo[maxEncodings];
var scores = detectedEncdings.Length;
var srcLen = input.Length;
// setup options (none)
var 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 (var 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[] DetectOutgoingEncodings(string input, int[] preferedEncodings, bool preserveOrder)
{
if (input == null)
throw new ArgumentNullException("input");
// empty strings can always be encoded as ASCII
if (input.Length == 0)
return new[] {Encoding.ASCII};
var result = new List<Encoding>();
// get the IMultiLanguage3 interface
IMultiLanguage3 multilang3 = new CMultiLanguageClass();
if (multilang3 == null)
throw new COMException("Failed to get IMultilang3");
try
{
var resultCodePages = new int[preferedEncodings.Length];
var detectedCodepages = (uint) resultCodePages.Length;
ushort specialChar = '?';
// get unmanaged arrays
var pPrefEncs = Marshal.AllocCoTaskMem(sizeof (uint)*preferedEncodings.Length);
var pDetectedEncs = preferedEncodings == null
? IntPtr.Zero
: Marshal.AllocCoTaskMem(sizeof (uint)*resultCodePages.Length);
try
{
if (preferedEncodings != null)
Marshal.Copy(preferedEncodings, 0, pPrefEncs, preferedEncodings.Length);
Marshal.Copy(resultCodePages, 0, pDetectedEncs, resultCodePages.Length);
var options = MLCPF.MLDETECTF_VALID_NLS | MLCPF.MLDETECTF_PREFERRED_ONLY;
if (preserveOrder)
options |= MLCPF.MLDETECTF_PRESERVE_ORDER;
if (preferedEncodings != null)
options |= MLCPF.MLDETECTF_PREFERRED_ONLY;
// finally... call to DetectOutboundCodePage
multilang3.DetectOutboundCodePage(options,
input, (uint) input.Length,
pPrefEncs, (uint) (preferedEncodings == null ? 0 : preferedEncodings.Length),
pDetectedEncs, ref detectedCodepages,
ref specialChar);
// get result
if (detectedCodepages > 0)
{
var theResult = new int[detectedCodepages];
Marshal.Copy(pDetectedEncs, theResult, 0, theResult.Length);
// get the encodings for the codepages
for (var i = 0; i < detectedCodepages; i++)
result.Add(Encoding.GetEncoding(theResult[i]));
}
}
finally
{
if (pPrefEncs != IntPtr.Zero)
Marshal.FreeCoTaskMem(pPrefEncs);
Marshal.FreeCoTaskMem(pDetectedEncs);
}
}
finally
{
Marshal.FinalReleaseComObject(multilang3);
}
// nothing found
return result.ToArray();
}
