package com.redhat.ceylon.eclipse.code.html;
import java.io.IOException;
import java.io.Reader;
/**
* Reads the text contents from a reader and computes for each
* character a potential substitution. The substitution may eat
* more characters than only the one passed into the computation
* routine.
*/
public abstract class SubstitutionTextReader
extends SingleCharReader {
protected static final String LINE_DELIM =
System.getProperty("line.separator", "\n");
private Reader fReader;
protected boolean fWasWhiteSpace;
private int fCharAfterWhiteSpace;
/**
* Tells whether white space characters are skipped.
*/
private boolean fSkipWhiteSpace = true;
private boolean fReadFromBuffer;
private StringBuffer fBuffer;
private int fIndex;
protected SubstitutionTextReader(Reader reader) {
fReader = reader;
fBuffer = new StringBuffer();
fIndex = 0;
fReadFromBuffer = false;
fCharAfterWhiteSpace = -1;
fWasWhiteSpace = true;
}
/**
* Computes the substitution for the given character and
* if necessary subsequent characters. Implementation
* should use <code>nextChar</code> to read subsequent
* characters.
*
* @param c the character to be substituted
* @return the substitution for <code>c</code>
* @throws IOException in case computing the substitution
* fails
*/
protected abstract String computeSubstitution(int c)
throws IOException;
protected Reader getReader() {
return fReader;
}
/**
* Returns the next character.
* @return the next character
* @throws IOException in case reading the character fails
*/
protected int nextChar()
throws IOException {
fReadFromBuffer= (fBuffer.length() > 0);
if (fReadFromBuffer) {
char ch= fBuffer.charAt(fIndex++);
if (fIndex >= fBuffer.length()) {
fBuffer.setLength(0);
fIndex= 0;
}
return ch;
}
int ch= fCharAfterWhiteSpace;
if (ch == -1) {
ch= fReader.read();
}
if (fSkipWhiteSpace &&
Character.isWhitespace((char)ch)) {
do {
ch= fReader.read();
}
while (Character.isWhitespace((char)ch));
if (ch != -1) {
fCharAfterWhiteSpace= ch;
return ' ';
}
}
else {
fCharAfterWhiteSpace= -1;
}
return ch;
}
public int read()
throws IOException {
int c;
do {
c= nextChar();
while (!fReadFromBuffer && c != -1) {
String s= computeSubstitution(c);
if (s == null)
break;
if (s.length() > 0)
fBuffer.insert(0, s);
c= nextChar();
}
}
while (fSkipWhiteSpace && fWasWhiteSpace && (c == ' '));
fWasWhiteSpace = (c == ' ' || c == '\r' || c == '\n');
return c;
}
public boolean ready()
throws IOException {
return fReader.ready();
}
public void close()
throws IOException {
fReader.close();
}
public void reset()
throws IOException {
fReader.reset();
fWasWhiteSpace = true;
fCharAfterWhiteSpace = -1;
fBuffer.setLength(0);
fIndex= 0;
}
protected final void setSkipWhitespace(boolean state) {
fSkipWhiteSpace= state;
}
protected final boolean isSkippingWhitespace() {
return fSkipWhiteSpace;
}
}