private void OnError(string message, Location position, Exception cause) {
throw new ParserException(message + ", line " + position.Line + " col " + position.Col, cause);
}
private Resource ResolveQName(string str, ParseContext context, Location loc) {
int colon = str.IndexOf(":");
string prefix = str.Substring(0, colon);
if (prefix == "_") {
Resource ret = (Resource)context.anonymous[str];
if (ret == null) {
ret = new Entity(null);
context.anonymous[str] = ret;
}
return ret;
} else if (prefix == "") {
return GetResource(context, (BaseUri == null ? "" : BaseUri) + str.Substring(colon+1));
} else {
string ns = context.namespaces.GetNamespace(prefix);
if (ns == null)
OnError("Prefix is undefined: " + str, loc);
return GetResource(context, ns + str.Substring(colon+1));
}
}
private void Add(StatementSink store, Statement statement, Location position) {
try {
store.Add(statement);
} catch (Exception e) {
OnError("Add failed on statement { " + statement + " }: " + e.Message, position, e);
}
}
private void ReadEscapedChar(char c, StringBuilder b, MyReader source, Location loc) {
if (c == 'n') b.Append('\n');
else if (c == 'r') b.Append('\r');
else if (c == 't') b.Append('\t');
else if (c == '\\') b.Append('\\');
else if (c == '"') b.Append('"');
else if (c == '\'') b.Append('\'');
else if (c == 'a') b.Append('\a');
else if (c == 'b') b.Append('\b');
else if (c == 'f') b.Append('\f');
else if (c == 'v') b.Append('\v');
else if (c == '\n') { }
else if (c == '\r') { }
else if (c == 'u' || c == 'U') {
StringBuilder num = new StringBuilder();
if (c == 'u') {
num.Append((char)source.Read()); // four hex digits
num.Append((char)source.Read());
num.Append((char)source.Read());
num.Append((char)source.Read());
} else {
source.Read(); // two zeros
source.Read();
num.Append((char)source.Read()); // six hex digits
num.Append((char)source.Read());
num.Append((char)source.Read());
num.Append((char)source.Read());
num.Append((char)source.Read());
num.Append((char)source.Read());
}
int unicode = int.Parse(num.ToString(), System.Globalization.NumberStyles.AllowHexSpecifier);
b.Append((char)unicode); // is this correct?
} else if (char.IsDigit((char)c) || c == 'x')
OnError("Octal and hex byte-value escapes are deprecated and not supported", loc);
else
OnError("Unrecognized escape character: " + (char)c, loc);
}
private object ReadToken(MyReader source, ParseContext context) {
ReadWhitespace(source);
Location loc = new Location(source.Line, source.Col);
int firstchar = source.Read();
if (firstchar == -1)
return "";
StringBuilder b = readTokenBuffer; readTokenBuffer.Length = 0;
b.Append((char)firstchar);
if (firstchar == '<') {
// This is a URI or the <= verb. URIs can be escaped like strings, at least in the NTriples spec.
bool escaped = false;
while (true) {
int c = source.Read();
if (c == -1) OnError("Unexpected end of stream within a token beginning with <", loc);
if (b.Length == 2 && c == '=')
return "<="; // the <= verb
if (escaped) {
ReadEscapedChar((char)c, b, source, loc);
escaped = false;
} else if (c == '\\') {
escaped = true;
} else {
b.Append((char)c);
if (c == '>') // end of the URI
break;
}
}
} else if (firstchar == '"') {
// A string: ("""[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*""")|("[^"\\]*(?:\\.[^"\\]*)*")
// What kind of crazy regex is this??
b.Length = 0; // get rid of the open quote
bool escaped = false;
bool triplequoted = false;
while (true) {
int c = source.Read();
if (c == -1) OnError("Unexpected end of stream within a string", loc);
if (b.Length == 0 && c == (int)'"' && source.Peek() == (int)'"') {
triplequoted = true;
source.Read();
continue;
}
if (!escaped && c == '\\')
escaped = true;
else if (escaped) {
ReadEscapedChar((char)c, b, source, loc);
escaped = false;
} else {
if (c == '"' && !triplequoted)
break;
if (c == '"' && source.Peek() == '"' && source.Peek2() == '"' && triplequoted)
break;
b.Append((char)c);
}
}
if (triplequoted) { // read the extra end quotes
source.Read();
source.Read();
}
string litvalue = b.ToString();
string litlang = null;
string litdt = null;
// Strings can be suffixed with @langcode or ^^symbol (but not both?).
if (source.Peek() == '@') {
source.Read();
b.Length = 0;
while (char.IsLetterOrDigit((char)source.Peek()) || source.Peek() == (int)'-')
b.Append((char)source.Read());
litlang = b.ToString();
} else if (source.Peek() == '^' && source.Peek2() == '^') {
loc = new Location(source.Line, source.Col);
source.Read();
source.Read();
litdt = ReadToken(source, context).ToString(); // better be a string URI
if (litdt.StartsWith("<") && litdt.EndsWith(">"))
litdt = litdt.Substring(1, litdt.Length-2);
else if (litdt.IndexOf(":") != -1) {
Resource r = ResolveQName(litdt, context, loc);
if (r.Uri == null)
OnError("A literal datatype cannot be an anonymous entity", loc);
litdt = r.Uri;
}
}
return new Literal(litvalue, litlang, litdt);
} else if (char.IsLetter((char)firstchar) || firstchar == '?' || firstchar == '@' || firstchar == ':' || firstchar == '_') {
// Something starting with @
// A QName: ([a-zA-Z_][a-zA-Z0-9_]*)?:)?([a-zA-Z_][a-zA-Z0-9_]*)?
// A variable: \?[a-zA-Z_][a-zA-Z0-9_]*
while (true) {
int c = source.Peek();
if (c == -1 || (!char.IsLetterOrDigit((char)c) && c != '-' && c != '_' && c != ':')) break;
b.Append((char)source.Read());
}
} else if (char.IsDigit((char)firstchar) || firstchar == '+' || firstchar == '-') {
while (true) {
int ci = source.Peek();
if (ci == -1) break;
// punctuation followed by a space means the punctuation is
// punctuation, and not part of this token
if (!char.IsDigit((char)ci) && source.Peek2() != -1 && char.IsWhiteSpace((char)source.Peek2()))
break;
char c = (char)ci;
if (char.IsWhiteSpace(c)) break;
b.Append((char)source.Read());
}
} else if (firstchar == '=') {
if (source.Peek() == (int)'>')
b.Append((char)source.Read());
} else if (firstchar == '[') {
// The start of an anonymous node.
} else if (firstchar == '{') {
return "{";
} else if (firstchar == '(') {
return "(";
} else if (firstchar == ')') {
return ")";
} else {
while (true) {
int c = source.Read();
if (c == -1) break;
if (char.IsWhiteSpace((char)c)) break;
b.Append((char)c);
}
OnError("Invalid token: " + b.ToString(), loc);
}
return b.ToString();
}
private void OnWarning(string message, Location position) {
base.OnWarning(message + ", line " + position.Line + " col " + position.Col);
}
private void OnWarning(string message, Location position, Exception cause) {
OnWarning(message + ", line " + position.Line + " col " + position.Col);
}
private void Add(StatementSink store, Statement statement, Location position) {
try {
store.Add(statement);
} catch (Exception e) {
if (!addFailuresAsWarnings)
OnError("Add failed on statement { " + statement + " }: " + e.Message, position, e);
else
OnWarning("Add failed on statement { " + statement + " }: " + e.Message, position, e);
}
}
private object ReadToken(MyReader source, ParseContext context) {
ReadWhitespace(source);
Location loc = new Location(source.Line, source.Col);
int firstchar = source.Read();
if (firstchar == -1)
return "";
StringBuilder b = readTokenBuffer; readTokenBuffer.Length = 0;
b.Append((char)firstchar);
if (firstchar == '<') {
// This is a URI or the <= verb. URIs can have \'s and <'s escaped with a backslash, plus \u and \U notation.
bool escaped = false;
while (true) {
int c = source.Read();
if (c == -1) OnError("Unexpected end of stream within a token beginning with <", loc);
if (b.Length == 2 && c == '=')
return "<="; // the <= verb
if (escaped) {
ReadEscapedChar((char)c, b, source, loc, true, true, false);
// the first flag should be set true only if not NTriples, but we are flexible on reading.
// the second flag should be set true only if NTriples, but we are flexible on reading.
escaped = false;
} else if (c == '\\') {
escaped = true;
} else {
b.Append((char)c);
if (c == '>') // end of the URI
break;
}
}
} else if (firstchar == '"') {
// This can either be a string "..." or a longString """...""", which additionally allows embedded \n, \r, and \t, and quotes.
b.Length = 0; // get rid of the open quote
bool escaped = false;
bool triplequoted = false;
while (true) {
int c = source.Read();
if (c == -1) OnError("Unexpected end of stream within a string", loc);
// Check if this is started by three quotes. If we've already read three quotes, don't keep checking or we can't read """""".
if (b.Length == 0 && c == (int)'"' && source.Peek() == (int)'"' && !triplequoted) {
triplequoted = true;
source.Read();
continue;
}
if (escaped) {
ReadEscapedChar((char)c, b, source, loc, false, true, true); // the last flag should be set true only if N3, but we are flexible on reading
escaped = false;
} else if (c == '\\') {
escaped = true;
} else {
if (c == '"' && !triplequoted)
break;
if (c == '"' && source.Peek() == '"' && source.Peek2() == '"' && triplequoted)
break;
b.Append((char)c);
}
}
if (triplequoted) { // read the extra end quotes
source.Read();
source.Read();
}
string litvalue = b.ToString();
string litlang = null;
string litdt = null;
// Strings can be suffixed with @langcode or ^^symbol (but not both?).
if (source.Peek() == '@') {
source.Read();
b.Length = 0;
while (char.IsLetterOrDigit((char)source.Peek()) || source.Peek() == (int)'-')
b.Append((char)source.Read());
litlang = b.ToString();
} else if (source.Peek() == '^' && source.Peek2() == '^') {
loc = new Location(source.Line, source.Col);
source.Read();
source.Read();
litdt = ReadToken(source, context).ToString(); // better be a string URI
if (litdt.StartsWith("<") && litdt.EndsWith(">"))
litdt = litdt.Substring(1, litdt.Length-2);
else if (litdt.IndexOf(":") != -1) {
Resource r = ResolveQName(litdt, context, loc);
if (r.Uri == null)
OnError("A literal datatype cannot be an anonymous entity", loc);
litdt = r.Uri;
}
}
Literal literal = new Literal(litvalue, litlang, litdt);
ValidateLiteral(literal);
return literal;
} else if (char.IsLetter((char)firstchar) || firstchar == '?' || firstchar == '@' || firstchar == ':' || firstchar == '_') {
// Something starting with @
// A QName: ([a-zA-Z_][a-zA-Z0-9_]*)?:)?([a-zA-Z_][a-zA-Z0-9_]*)?
// A variable: \?[a-zA-Z_][a-zA-Z0-9_]*
while (true) {
int c = source.Peek();
if (c == -1 || (!Entity.ValidateUriIsIUnreserved((char)c) && c != ':') || c == '.') break;
b.Append((char)source.Read());
}
} else if (char.IsDigit((char)firstchar) || firstchar == '+' || firstchar == '-') {
while (true) {
int ci = source.Peek();
if (ci == -1) break;
if (ci == ']' || ci == ')' || ci == '}') break;
// punctuation followed by a space means the punctuation is
// punctuation, and not part of this token
if (!char.IsDigit((char)ci) && source.Peek2() != -1 && char.IsWhiteSpace((char)source.Peek2()))
break;
char c = (char)ci;
if (char.IsWhiteSpace(c)) break;
b.Append((char)source.Read());
}
} else if (firstchar == '=') {
if (source.Peek() == (int)'>')
b.Append((char)source.Read());
if (source.Peek() == (int)':' && source.Peek2() == (int)'>') { // SPECIAL EXTENSION "=:>"
b.Append((char)source.Read());
b.Append((char)source.Read());
}
} else if (firstchar == '[') {
// The start of an anonymous node.
} else if (firstchar == '{') {
return "{";
} else if (firstchar == '(') {
return "(";
} else if (firstchar == ')') {
return ")";
} else {
while (true) {
int c = source.Read();
if (c == -1) break;
if (char.IsWhiteSpace((char)c)) break;
b.Append((char)c);
}
OnError("Invalid token: " + b.ToString(), loc);
}
return b.ToString();
}
private void ReadEscapedChar(char c, StringBuilder b, MyReader source, Location loc, bool esc3E, bool escSPQ, bool escN3) {
// AbsoluteURIs (NTriples), RelativeURIs (Turtle), strings, and longStrings all allow \'s to be escaped and u and U notation.
if (c == '\\') b.Append('\\');
else if (c == 'u' || c == 'U') {
StringBuilder num = new StringBuilder();
if (c == 'u') {
num.Append((char)source.Read()); // four hex digits
num.Append((char)source.Read());
num.Append((char)source.Read());
num.Append((char)source.Read());
} else {
source.Read(); // two zeros
source.Read();
num.Append((char)source.Read()); // six hex digits
num.Append((char)source.Read());
num.Append((char)source.Read());
num.Append((char)source.Read());
num.Append((char)source.Read());
num.Append((char)source.Read());
}
int unicode = int.Parse(num.ToString(), System.Globalization.NumberStyles.AllowHexSpecifier);
b.Append((char)unicode); // is this correct?
}
// RelativeURis in Turtle (but not string or longString or NTriples Absolute URis) allow >'s to be escaped.
else if (esc3E && c == '>') b.Append(">");
// AbsoluteURIs (NTriples), string, and longString allow the three space escapes and the double quote.
else if (escSPQ && c == 'n') b.Append('\n');
else if (escSPQ && c == 'r') b.Append('\r');
else if (escSPQ && c == 't') b.Append('\t');
else if (escSPQ && c == '"') b.Append('"');
// In Notation 3 strings, additional escapes are allowed.
else if (escN3 && c == '\'') b.Append('\'');
else if (escN3 && c == '\n') { }
else if (escN3 && c == '\r') { }
else if (char.IsDigit((char)c) || c == 'x' || c == 'a' || c == 'b' || c == 'f' || c == 'v')
OnError("Octal and hex byte-value escapes and other escapes are deprecated and not supported", loc);
else
OnError("Invalid escape character: " + (char)c, loc);
}
