package org.jruby.lexer.yacc;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.List;
import org.jruby.parser.ParserConfiguration;
import org.jruby.util.ByteList;
public class ReaderLexerSource extends LexerSource {
private static final int INITIAL_PUSHBACK_SIZE = 100;
// Where we get our newest char's
private final Reader in;
// Our readback/pushback buffer.
private char buf[] = new char[INITIAL_PUSHBACK_SIZE];
// index of last character in pushback buffer
private int bufLength = -1;
// Character read before previous read
private int oneAgo = '\n';
private int twoAgo = 0;
/**
* Create our food-source for the lexer
*
* @param sourceName is the file we are reading
* @param reader is what represents the contents of file sourceName
* @param line starting line number for source (used by eval)
* @param extraPositionInformation will gives us extra information that an IDE may want
*/
public ReaderLexerSource(String sourceName, Reader in, List<String> list, int line,
boolean extraPositionInformation) {
super(sourceName, list, line, extraPositionInformation);
this.in = in;
}
/**
* Read next character from this source
*
* @return next character to viewed by the source
*/
public int read() throws IOException {
int c;
if (bufLength >= 0) {
c = buf[bufLength--];
} else {
c = wrappedRead();
if (c == -1) return RubyYaccLexer.EOF;
}
twoAgo = oneAgo;
oneAgo = c;
offset++;
if (c == '\n') line++;
return c;
}
/**
* Pushes char back onto this source. Note, this also
* allows us to push whatever is passes back into the source.
*
* @param to be put back onto the source
*/
public void unread(int c) {
if (c == RubyYaccLexer.EOF) return;
offset--;
oneAgo = twoAgo;
twoAgo = 0;
if (c == '\n') line--;
buf[++bufLength] = (char) c;
// If we outgrow our pushback stack then grow it (this should only happen in pretty
// pathological cases).
if (bufLength + 1 == buf.length) {
char[] newBuf = new char[buf.length + INITIAL_PUSHBACK_SIZE];
System.arraycopy(buf, 0, newBuf, 0, buf.length);
buf = newBuf;
}
}
/**
* Is the next character equal to 'to'
* @param to character to compare against
* @return true if the same
* @throws IOException
*/
public boolean peek(int to) throws IOException {
// keep value of twoAgo around so we can restore after we unread
int captureTwoAgo = twoAgo;
int c = read();
unread(c);
twoAgo = captureTwoAgo;
return c == to;
}
/**
* Convenience method to hide exception. If we do hit an exception
* we will pretend we EOF'd.
*
* @return the current char or EOF (at EOF or on error)
*/
private int wrappedRead() throws IOException {
int c = in.read();
// If \r\n then just pass along \n (windows).
// If \r[^\n] then pass along \n (MAC).
if (c == '\r') {
if ((c = in.read()) != '\n') {
unread((char) c);
c = '\n';
} else {
// Position within source must reflect the actual offset and column. Since
// we ate an extra character here (this accounting is normally done in read
// ), we should update position info.
offset++;
}
}
captureFeature(c);
return c;
}
/**
* Create a source.
*
* @param name the name of the source (e.g a filename: foo.rb)
* @param content the data of the source
* @return the new source
*/
public static LexerSource getSource(String name, InputStream content, List<String> list,
ParserConfiguration configuration) {
return new InputStreamLexerSource(name, content, list, configuration.getLineNumber(),
configuration.hasExtraPositionInformation());
}
@Override
public ByteList readLineBytes() throws IOException {
ByteList bytelist = new ByteList(80);
for (int c = read(); c != '\n' && c != RubyYaccLexer.EOF; c = read()) {
bytelist.append(c);
}
return bytelist;
}
@Override
public int skipUntil(int c) throws IOException {
for (c = read(); c != '\n' && c != RubyYaccLexer.EOF; c = read()) {}
return c;
}
public void unreadMany(CharSequence buffer) {
int length = buffer.length();
for (int i = length - 1; i >= 0; i--) {
unread(buffer.charAt(i));
}
}
@Override
public boolean matchMarker(ByteList match, boolean indent, boolean checkNewline) throws IOException {
int length = match.length();
ByteList buffer = new ByteList(length + 1);
if (indent) {
int c;
while ((c = read()) != RubyYaccLexer.EOF) {
if (!Character.isWhitespace(c) || c == '\n') {
unread(c);
break;
}
buffer.append(c);
}
}
int c;
for (int i = 0; i < length; i++) {
c = read();
buffer.append(c);
if (match.charAt(i) != c) {
unreadMany(buffer);
return false;
}
}
if (!checkNewline) return true;
c = read();
if (c == RubyYaccLexer.EOF || c == '\n') return true;
buffer.append(c);
unreadMany(buffer);
return false;
}
/**
* Was the last character read from the stream the first character on a line
*
* @return true if so
*/
public boolean wasBeginOfLine() {
return twoAgo == '\n';
}
public boolean lastWasBeginOfLine() {
return oneAgo == '\n';
}
public String toString() {
try {
ByteList buffer = new ByteList(20);
buffer.append(twoAgo);
buffer.append(oneAgo);
buffer.append(new byte[] {'-', '>'});
int i = 0;
for (; i < 20; i++) {
int c = read();
if (c == 0) {
i--;
break;
}
buffer.append(c);
}
for (; i >= 0; i++) {
unread(buffer.charAt(i));
}
buffer.append(new byte[] {' ', '.', '.', '.'});
return buffer.toString();
} catch(Exception e) {
return null;
}
}
@Override
public ByteList readUntil(char marker) throws IOException {
ByteList list = new ByteList(20);
int c;
for (c = read(); c != marker && c != RubyYaccLexer.EOF; c = read()) {
list.append(c);
}
if (c == RubyYaccLexer.EOF) return null;
unread(c);
return list;
}
}