/**
* Parses the ASCII portion of a Type 1 font.
*/
private void ParseASCII(byte[] bytes)
{
if (bytes.Length == 0)
{
throw new ArgumentException("byte[] is empty");
}
// %!FontType1-1.0
// %!PS-AdobeFont-1.0
if (bytes.Length < 2 || (bytes[0] != '%' && bytes[1] != '!'))
{
throw new IOException("Invalid start of ASCII segment");
}
lexer = new Type1Lexer(bytes);
// (corrupt?) synthetic font
if (lexer.PeekToken().Text.Equals("FontDirectory", StringComparison.Ordinal))
{
Read(TokenKind.NAME, "FontDirectory");
Read(TokenKind.LITERAL); // font name
Read(TokenKind.NAME, "known");
Read(TokenKind.START_PROC);
ReadProc();
Read(TokenKind.START_PROC);
ReadProc();
Read(TokenKind.NAME, "ifelse");
}
// font dict
int Length = Read(TokenKind.INTEGER).IntValue;
Read(TokenKind.NAME, "dict");
// found in some TeX fonts
ReadMaybe(TokenKind.NAME, "dup");
// if present, the "currentdict" is not required
Read(TokenKind.NAME, "begin");
for (int i = 0; i < Length; i++)
{
// premature end
Token token = lexer.PeekToken();
if (token == null)
{
break;
}
if (token.Kind == TokenKind.NAME &&
("currentdict".Equals(token.Text, StringComparison.Ordinal) ||
"end".Equals(token.Text, StringComparison.Ordinal)))
{
break;
}
// key/value
string key = Read(TokenKind.LITERAL).Text;
switch (key)
{
case "FontInfo":
case "Fontinfo":
ReadFontInfo(ReadSimpleDict());
break;
case "Metrics":
ReadSimpleDict();
break;
case "Encoding":
ReadEncoding();
break;
default:
ReadSimpleValue(key);
break;
}
}
ReadMaybe(TokenKind.NAME, "currentdict");
Read(TokenKind.NAME, "end");
Read(TokenKind.NAME, "currentfile");
Read(TokenKind.NAME, "eexec");
}
/**
* Parses the binary portion of a Type 1 font.
*/
private void ParseBinary(byte[] bytes)
{
byte[] decrypted;
// Sometimes, fonts use the hex format, so this needs to be converted before decryption
if (IsBinary(bytes))
{
decrypted = Decrypt(bytes, EEXEC_KEY, 4);
}
else
{
decrypted = Decrypt(hexToBinary(bytes), EEXEC_KEY, 4);
}
lexer = new Type1Lexer(decrypted);
// find /Private dict
Token peekToken = lexer.PeekToken();
while (peekToken != null && !peekToken.Text.Equals("Private", StringComparison.Ordinal))
{
// for a more thorough validation, the presence of "begin" before Private
// determines how code before and following charstrings should look
// it is not currently checked anyway
lexer.NextToken();
peekToken = lexer.PeekToken();
}
if (peekToken == null)
{
throw new IOException("/Private token not found");
}
// Private dict
Read(TokenKind.LITERAL, "Private");
int Length = Read(TokenKind.INTEGER).IntValue;
Read(TokenKind.NAME, "dict");
// actually could also be "/Private 10 dict def Private begin"
// instead of the "dup"
ReadMaybe(TokenKind.NAME, "dup");
Read(TokenKind.NAME, "begin");
int lenIV = 4; // number of random bytes at start of charstring
for (int i = 0; i < Length; i++)
{
// premature end
if (lexer.PeekToken() == null || lexer.PeekToken().Kind != TokenKind.LITERAL)
{
break;
}
// key/value
string key = Read(TokenKind.LITERAL).Text;
switch (key)
{
case "Subrs":
ReadSubrs(lenIV);
break;
case "OtherSubrs":
ReadOtherSubrs();
break;
case "lenIV":
lenIV = ReadDictValue()[0].IntValue;
break;
case "ND":
Read(TokenKind.START_PROC);
// the access restrictions are not mandatory
ReadMaybe(TokenKind.NAME, "noaccess");
Read(TokenKind.NAME, "def");
Read(TokenKind.END_PROC);
ReadMaybe(TokenKind.NAME, "executeonly");
Read(TokenKind.NAME, "def");
break;
case "NP":
Read(TokenKind.START_PROC);
ReadMaybe(TokenKind.NAME, "noaccess");
Read(TokenKind.NAME);
Read(TokenKind.END_PROC);
ReadMaybe(TokenKind.NAME, "executeonly");
Read(TokenKind.NAME, "def");
break;
case "RD":
// /RD {string currentfile exch readstring pop} bind executeonly def
Read(TokenKind.START_PROC);
ReadProc();
ReadMaybe(TokenKind.NAME, "bind");
ReadMaybe(TokenKind.NAME, "executeonly");
Read(TokenKind.NAME, "def");
break;
default:
ReadPrivate(key, ReadDictValue());
break;
}
}
// some fonts have "2 index" here, others have "end noaccess put"
// sometimes followed by "put". Either way, we just skip until
// the /CharStrings dict is found
while (!(lexer.PeekToken().Kind == TokenKind.LITERAL &&
lexer.PeekToken().Text.Equals("CharStrings", StringComparison.Ordinal)))
{
lexer.NextToken();
}
// CharStrings dict
Read(TokenKind.LITERAL, "CharStrings");
ReadCharStrings(lenIV);
}
