/// <summary>
/// Initializes a new instance of the <see cref="MimeKit.IO.Filters.CharsetFilter"/> class.
/// </summary>
/// <remarks>
/// Creates a new <see cref="CharsetFilter"/> to convert text from the specified
/// source encoding into the target charset encoding.
/// </remarks>
/// <param name="sourceEncoding">Source encoding.</param>
/// <param name="targetEncoding">Target encoding.</param>
/// <exception cref="System.ArgumentNullException">
/// <para><paramref name="sourceEncoding"/> is <c>null</c>.</para>
/// <para>-or-</para>
/// <para><paramref name="targetEncoding"/> is <c>null</c>.</para>
/// </exception>
public CharsetFilter(Encoding sourceEncoding, Encoding targetEncoding)
{
if (sourceEncoding == null)
{
throw new ArgumentNullException(nameof(sourceEncoding));
}
if (targetEncoding == null)
{
throw new ArgumentNullException(nameof(targetEncoding));
}
SourceEncoding = sourceEncoding;
TargetEncoding = targetEncoding;
decoder = (Decoder)SourceEncoding.GetDecoder();
encoder = (Encoder)TargetEncoding.GetEncoder();
}
static int Rfc2047EncodeNextChunk(StringBuilder str, string text, ref int index, Encoding encoding, string charset, Encoder encoder, int maxLength)
{
int byteCount = 0, charCount = 0, encodeCount = 0;
var buffer = new char[2];
int startIndex = index;
int nchars, n;
char c;
while (index < text.Length)
{
c = text[index++];
if (c < 127)
{
if (IsCtrl(c) || c == '"' || c == '\\')
{
encodeCount++;
}
byteCount++;
charCount++;
nchars = 1;
n = 1;
}
else if (c < 256)
{
// iso-8859-1
encodeCount++;
byteCount++;
charCount++;
nchars = 1;
n = 1;
}
else
{
if (char.IsSurrogatePair(text, index - 1))
{
buffer[1] = text[index++];
nchars = 2;
}
else
{
nchars = 1;
}
buffer[0] = c;
try {
n = encoder.GetByteCount(buffer, 0, nchars, true);
} catch {
n = 3;
}
charCount += nchars;
encodeCount += n;
byteCount += n;
}
if (ExceedsMaxWordLength(charset, byteCount, encodeCount, maxLength))
{
// restore our previous state
charCount -= nchars;
index -= nchars;
byteCount -= n;
break;
}
}
return(Rfc2047.AppendEncodedWord(str, encoding, text, startIndex, charCount, QEncodeMode.Text));
}
static bool Rfc2231GetNextValue(FormatOptions options, string charset, Encoder encoder, HexEncoder hex, char[] chars, ref int index, ref byte[] bytes, ref byte[] encoded, int maxLength, out string value)
{
int length = chars.Length - index;
if (length < maxLength)
{
switch (GetEncodeMethod(options, chars, index, length))
{
case EncodeMethod.Quote:
value = MimeUtils.Quote(new string (chars, index, length));
index += length;
return(false);
case EncodeMethod.None:
value = new string (chars, index, length);
index += length;
return(false);
}
}
length = Math.Min(maxLength, length);
int ratio, count, n;
do
{
count = encoder.GetByteCount(chars, index, length, true);
if (count > maxLength && length > 1)
{
if ((ratio = (int)Math.Round((double)count / (double)length)) > 1)
{
length -= Math.Max((count - maxLength) / ratio, 1);
}
else
{
length--;
}
continue;
}
if (bytes.Length < count)
{
Array.Resize <byte> (ref bytes, count);
}
count = encoder.GetBytes(chars, index, length, bytes, 0, true);
// Note: the first chunk needs to be encoded in order to declare the charset
if (index > 0 || charset == "us-ascii")
{
var method = GetEncodeMethod(bytes, count);
if (method == EncodeMethod.Quote)
{
value = MimeUtils.Quote(Encoding.ASCII.GetString(bytes, 0, count));
index += length;
return(false);
}
if (method == EncodeMethod.None)
{
value = Encoding.ASCII.GetString(bytes, 0, count);
index += length;
return(false);
}
}
n = hex.EstimateOutputLength(count);
if (encoded.Length < n)
{
Array.Resize <byte> (ref encoded, n);
}
// only the first value gets a charset declaration
int charsetLength = index == 0 ? charset.Length + 2 : 0;
n = hex.Encode(bytes, 0, count, encoded);
if (n > 3 && (charsetLength + n) > maxLength)
{
int x = 0;
for (int i = n - 1; i >= 0 && charsetLength + i >= maxLength; i--)
{
if (encoded[i] == (byte)'%')
{
x--;
}
else
{
x++;
}
}
if ((ratio = (int)Math.Round((double)count / (double)length)) > 1)
{
length -= Math.Max(x / ratio, 1);
}
else
{
length--;
}
continue;
}
if (index == 0)
{
value = charset + "''" + Encoding.ASCII.GetString(encoded, 0, n);
}
else
{
value = Encoding.ASCII.GetString(encoded, 0, n);
}
index += length;
return(true);
} while (true);
}
/// <summary>
/// Initializes a new instance of the <see cref="MimeKit.IO.Filters.CharsetFilter"/> class.
/// </summary>
/// <remarks>
/// Creates a new <see cref="CharsetFilter"/> to convert text from the specified
/// source encoding into the target charset encoding.
/// </remarks>
/// <param name="sourceEncoding">Source encoding.</param>
/// <param name="targetEncoding">Target encoding.</param>
/// <exception cref="System.ArgumentNullException">
/// <para><paramref name="sourceEncoding"/> is <c>null</c>.</para>
/// <para>-or-</para>
/// <para><paramref name="targetEncoding"/> is <c>null</c>.</para>
/// </exception>
public CharsetFilter (Encoding sourceEncoding, Encoding targetEncoding)
{
if (sourceEncoding == null)
throw new ArgumentNullException ("sourceEncoding");
if (targetEncoding == null)
throw new ArgumentNullException ("targetEncoding");
SourceEncoding = sourceEncoding;
TargetEncoding = targetEncoding;
decoder = (Decoder) SourceEncoding.GetDecoder ();
encoder = (Encoder) TargetEncoding.GetEncoder ();
}
static bool GetNextValue (string charset, Encoder encoder, HexEncoder hex, char[] chars, ref int index,
ref byte[] bytes, ref byte[] encoded, int maxLength, out string value)
{
int length = chars.Length - index;
if (length < maxLength) {
switch (GetEncodeMethod (chars, index, length)) {
case EncodeMethod.Quote:
value = MimeUtils.Quote (new string (chars, index, length));
index += length;
return false;
case EncodeMethod.None:
value = new string (chars, index, length);
index += length;
return false;
}
}
length = Math.Min (maxLength, length);
int ratio, count, n;
do {
count = encoder.GetByteCount (chars, index, length, true);
if (count > maxLength && length > 1) {
ratio = (int) Math.Round ((double) count / (double) length);
length -= Math.Max ((count - maxLength) / ratio, 1);
continue;
}
if (bytes.Length < count)
Array.Resize<byte> (ref bytes, count);
count = encoder.GetBytes (chars, index, length, bytes, 0, true);
// Note: the first chunk needs to be encoded in order to declare the charset
if (index > 0 || charset == "us-ascii") {
var method = GetEncodeMethod (bytes, count);
if (method == EncodeMethod.Quote) {
value = MimeUtils.Quote (Encoding.ASCII.GetString (bytes, 0, count));
index += length;
return false;
}
if (method == EncodeMethod.None) {
value = Encoding.ASCII.GetString (bytes, 0, count);
index += length;
return false;
}
}
n = hex.EstimateOutputLength (count);
if (encoded.Length < n)
Array.Resize<byte> (ref encoded, n);
// only the first value gets a charset declaration
int charsetLength = index == 0 ? charset.Length + 2 : 0;
n = hex.Encode (bytes, 0, count, encoded);
if (n > 3 && (charsetLength + n) > maxLength) {
int x = 0;
for (int i = n - 1; i >= 0 && charsetLength + i >= maxLength; i--) {
if (encoded[i] == (byte) '%')
x--;
else
x++;
}
ratio = (int) Math.Round ((double) count / (double) length);
length -= Math.Max (x / ratio, 1);
continue;
}
if (index == 0)
value = charset + "''" + Encoding.ASCII.GetString (encoded, 0, n);
else
value = Encoding.ASCII.GetString (encoded, 0, n);
index += length;
return true;
} while (true);
}
static int Rfc2047EncodeNextChunk (StringBuilder str, string text, ref int index, Encoding encoding, string charset, Encoder encoder, int maxLength)
{
int byteCount = 0, charCount = 0, encodeCount = 0;
var buffer = new char[2];
int startIndex = index;
int nchars, n;
char c;
while (index < text.Length) {
c = text[index++];
if (c < 127) {
if (IsCtrl (c) || c == '"' || c == '\\')
encodeCount++;
byteCount++;
charCount++;
nchars = 1;
n = 1;
} else if (c < 256) {
// iso-8859-1
encodeCount++;
byteCount++;
charCount++;
nchars = 1;
n = 1;
} else {
if (char.IsSurrogatePair (text, index - 1)) {
buffer[1] = text[index++];
nchars = 2;
} else {
nchars = 1;
}
buffer[0] = c;
try {
n = encoder.GetByteCount (buffer, 0, nchars, true);
} catch {
n = 3;
}
charCount += nchars;
encodeCount += n;
byteCount += n;
}
if (ExceedsMaxWordLength (charset, byteCount, encodeCount, maxLength)) {
// restore our previous state
charCount -= nchars;
index -= nchars;
byteCount -= n;
break;
}
}
return Rfc2047.AppendEncodedWord (str, encoding, text, startIndex, charCount, QEncodeMode.Text);
}
/// <summary>
/// Initializes a new instance of the <see cref="MimeKit.Text.TextConverter"/> class.
/// </summary>
/// <remarks>
/// Initializes a new instance of the <see cref="MimeKit.Text.TextConverter"/> class.
/// </remarks>
protected TextConverter()
{
encoder = Encoding.UTF8.GetEncoder();
decoder = Encoding.UTF8.GetDecoder();
}
/// <summary>
/// Initializes a new instance of the <see cref="MimeKit.Text.TextConverter"/> class.
/// </summary>
/// <remarks>
/// Initializes a new instance of the <see cref="MimeKit.Text.TextConverter"/> class.
/// </remarks>
protected TextConverter ()
{
encoder = Encoding.UTF8.GetEncoder ();
decoder = Encoding.UTF8.GetDecoder ();
}
