// get the value of a parameter
bool MimeField::GetParameter(const char* pszAttr, AnsiString& strValue) const
{
strValue = "";
bool encodedParameter = false;
vector<AnsiString> parameters = StringParser::SplitString(AnsiString(m_strValue), ";");
for (unsigned int i = 1; i < parameters.size(); i++)
{
AnsiString value = parameters[i];
value.TrimLeft();
// Locate end of parameter name.
int nameEndPos = 0;
for (nameEndPos = 0; nameEndPos < value.GetLength(); nameEndPos++)
{
char c = value[nameEndPos];
if (c == ' ' || c == '*' || c == '=')
break;
}
// If we haven't found any value for this parameter, bail out.
if (nameEndPos == 0 && strValue.IsEmpty())
return false;
AnsiString parameterName = value.Mid(0, nameEndPos);
if (parameterName.CompareNoCase(pszAttr) != 0)
continue;
// Locate start of parameter value.
int valuePos = 0;
for (valuePos = nameEndPos; valuePos < value.GetLength(); valuePos++)
{
char c = value[valuePos];
if (c == '=')
break;
}
// We want the char before = NOT char after param name
// to detect encoding per RFC 2231 4.1
// http://www.hmailserver.com/forum/viewtopic.php?f=10&t=21417
char characterBeforeEquals = value[valuePos - 1];
if (characterBeforeEquals == '*')
encodedParameter = true;
// Skip past the equal sign.
valuePos++;
// Locate the start of the actual value. May be enclosed with quotes.
//
// For instance, this is perfectly valid
// Content-Type: text/plain; charset = "iso-8859-1"
//
for (; valuePos < value.GetLength(); valuePos++)
{
char c = value[valuePos];
if (c == ' ' || c == '"')
continue;
else
break;
}
// Locate the end of the value. The value may contain
// pretty much any character, including space.
int valueEndPos = valuePos;
for (; valueEndPos < value.GetLength(); valueEndPos++)
{
char c = value[valueEndPos];
if (c == ';' || c == '"')
break;
else
continue;
}
int valueLength = valueEndPos - valuePos;
value = value.Mid(valuePos, valueLength);
// If the value is
// Content-Type: text/plain; charset = "iso-8859-1"
// it needs to be trimmed.
value.TrimRight();
strValue.append(value);
}
if (strValue.IsEmpty())
return false;
/*
(2) MIME headers, like the RFC 822 headers they often
appear in, are limited to 7bit US-ASCII, and the
encoded-word mechanisms of RFC 2047 are not available
to parameter values. This makes it impossible to have
parameter values in character sets other than US-ASCII
without specifying some sort of private per-parameter
encoding.
http://tools.ietf.org/html/draft-freed-pvcsc-03
Examples:
Input: ISO-8859-1''%E9%2E%70%6E%67
Output: =?ISO-8859-1?Q?=E9=2Epng?=
*/
if (encodedParameter)
{
MimeParameterRFC2184Decoder decoder;
strValue.assign(decoder.Decode(strValue));
}
strValue.TrimLeft();
return true;
}