internal static MimeStringList EncodeValue(string value, EncodingOptions encodingOptions, ValueEncodingStyle style)
{
if (string.IsNullOrEmpty(value))
{
return(MimeStringList.Empty);
}
if (!MimeCommon.IsEncodingRequired(value, encodingOptions.AllowUTF8))
{
return(new MimeStringList(new MimeString(value)));
}
MimeStringList result = default(MimeStringList);
Charset encodingCharset;
if (encodingOptions.CharsetName != null)
{
encodingCharset = encodingOptions.GetEncodingCharset();
}
else
{
OutboundCodePageDetector outboundCodePageDetector = new OutboundCodePageDetector();
outboundCodePageDetector.AddText(value);
int codePage = outboundCodePageDetector.GetCodePage();
if (!Charset.TryGetCharset(codePage, out encodingCharset))
{
encodingCharset = MimeCommon.DefaultEncodingOptions.GetEncodingCharset();
}
}
ByteEncoder.Tables.CharClasses charClasses = ByteEncoder.Tables.CharClasses.QEncode;
if (style == ValueEncodingStyle.Phrase)
{
charClasses |= ByteEncoder.Tables.CharClasses.QPhraseUnsafe;
}
else if (style == ValueEncodingStyle.Comment)
{
charClasses |= ByteEncoder.Tables.CharClasses.QCommentUnsafe;
}
bool allowQEncoding = false;
MimeCommon.CalculateMethodAndChunkSize calculateMethodAndChunkSize;
if (encodingCharset.Kind == CodePageKind.Sbcs)
{
calculateMethodAndChunkSize = MimeCommon.calculateMethodAndChunkSizeSbcs;
if (encodingCharset.AsciiSupport >= CodePageAsciiSupport.Fine)
{
allowQEncoding = true;
}
}
else if (encodingCharset.Kind == CodePageKind.Dbcs)
{
calculateMethodAndChunkSize = MimeCommon.calculateMethodAndChunkSizeDbcs;
if (encodingCharset.AsciiSupport >= CodePageAsciiSupport.Fine)
{
allowQEncoding = true;
}
}
else if (encodingCharset.CodePage == 65001)
{
calculateMethodAndChunkSize = MimeCommon.calculateMethodAndChunkSizeUtf8;
allowQEncoding = true;
}
else if (encodingCharset.CodePage == 1200 || encodingCharset.CodePage == 1201)
{
calculateMethodAndChunkSize = MimeCommon.calculateMethodAndChunkSizeUnicode16;
}
else if (encodingCharset.CodePage == 12000 || encodingCharset.CodePage == 12001)
{
calculateMethodAndChunkSize = MimeCommon.calculateMethodAndChunkSizeUnicode32;
}
else
{
calculateMethodAndChunkSize = MimeCommon.calculateMethodAndChunkSizeMbcs;
}
int num = 75;
int num2 = 7 + encodingCharset.Name.Length;
int num3 = num - num2;
if (num3 < 32)
{
num = num2 + 32;
num3 = 32;
}
byte[] byteBuffer = ScratchPad.GetByteBuffer(num3);
Encoding encoding = encodingCharset.GetEncoding();
byte[] array = new byte[5 + encodingCharset.Name.Length];
int num4 = 0;
array[num4++] = 61;
array[num4++] = 63;
num4 += ByteString.StringToBytes(encodingCharset.Name, array, num4, false);
array[num4++] = 63;
array[num4++] = 88;
array[num4++] = 63;
MimeString mimeString = new MimeString(array);
int num5 = 0;
byte[] array2 = null;
int num6 = 0;
int num7 = num3 / 4;
while (num5 != value.Length)
{
byte b;
int num8;
calculateMethodAndChunkSize(allowQEncoding, charClasses, encoding, value, num5, num3, out b, out num8);
int bytes;
int num10;
for (;;)
{
for (;;)
{
try
{
bytes = encoding.GetBytes(value, num5, num8, byteBuffer, 0);
}
catch (ArgumentException)
{
if (num8 < 2)
{
throw;
}
num8 -= ((num8 > 10) ? 3 : 1);
if (MimeCommon.IsLowSurrogate(value[num5 + num8]) && MimeCommon.IsHighSurrogate(value[num5 + num8 - 1]))
{
num8--;
}
break;
}
if (bytes == 0)
{
goto IL_424;
}
if (array2 == null || array2.Length - num6 < num + 1)
{
if (array2 != null)
{
result.Append(new MimeString(array2, 0, num6));
num6 = 0;
}
int val = ((value.Length - num5) / num8 + 1) * (num + 1);
int num9 = Math.Min(val, 4096 / (num + 1) * (num + 1));
array2 = new byte[num9];
}
num10 = num6;
if (result.Count > 0 || num10 > 0)
{
array2[num10++] = 32;
}
num10 += mimeString.CopyTo(array2, num10);
array2[num10 - 2] = b;
if (b != 81)
{
goto IL_3F5;
}
int num11 = num10;
int num12 = 0;
while (num12 < bytes && num10 - num11 + 1 <= num3)
{
byte b2 = byteBuffer[num12];
if (MimeCommon.QEncodingRequired((char)b2, charClasses))
{
if (num10 - num11 + 3 > num3)
{
break;
}
array2[num10++] = 61;
array2[num10++] = ByteEncoder.NibbleToHex[b2 >> 4];
array2[num10++] = ByteEncoder.NibbleToHex[(int)(b2 & 15)];
}
else
{
if (b2 == 32)
{
b2 = 95;
}
array2[num10++] = b2;
}
num12++;
}
if (num12 == bytes)
{
goto IL_408;
}
if (num8 < 2)
{
goto Block_26;
}
num8 -= ((num8 > 10) ? 3 : 1);
if (MimeCommon.IsLowSurrogate(value[num5 + num8]) && MimeCommon.IsHighSurrogate(value[num5 + num8 - 1]))
{
num8--;
}
}
}
IL_424:
num5 += num8;
continue;
Block_26:
throw new InvalidOperationException("unexpected thing just happened");
IL_408:
array2[num10++] = 63;
array2[num10++] = 61;
num6 = num10;
goto IL_424;
IL_3F5:
num10 += MimeCommon.Base64EncodeChunk(byteBuffer, 0, bytes, array2, num10);
goto IL_408;
}
if (array2 != null)
{
result.Append(new MimeString(array2, 0, num6));
}
return(result);
}