Mega Code Archive
Line string reader in J2ME
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//package util.io;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
/**
* line string reader in J2ME
* @author celon
*
*/
public class TextFileReader extends Reader {
private InputStream is;
private byte[] buffer = new byte[65535];
private int index = buffer.length;
private StringBuffer sb = new StringBuffer();
private boolean fileEOF = false;
private int scanEndIndex;
private static final String UTF_ENCODE = "UTF-8";
private static final char endChar = '\n';
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
}
public TextFileReader(InputStream _is) {
is = _is;
}
public void close() throws IOException {
is.close();
}
/**
* never use it
*/
public int read(char[] cbuf, int off, int len) throws IOException {
return 0;
}
/**
* read a line from text file, return null when get EOF
* @return
* @throws IOException
*/
public String readLine() throws IOException {
boolean endFound = false;
while (!endFound) {
//add string to buffer until found endChar
if (!fileEOF) {
scanEndIndex = buffer.length;
if (index >= buffer.length) {
//reload from file and reset index
int bufferByteNum = readToBuffer();
index = 0;
if (bufferByteNum < buffer.length) {
scanEndIndex = bufferByteNum;
fileEOF = true;
}
}
}
for (; index < scanEndIndex; index++) {
if (buffer[index] == endChar) {
//found line end
endFound = true;
//skip endChar
index++;
return returnBuffer();
} else {
//append to buffer
sb.append((char) (buffer[index]));
}
}
if (endFound) {
return returnBuffer();
} else if (fileEOF) {
return returnBuffer();
}
}
return null;
}
private int readToBuffer() throws IOException {
int result = is.read(buffer);
return result;
}
private String returnBuffer() {
if (sb.length() == 0)
return null;
byte[] data = new byte[sb.length()];
for (int i = 0; i < data.length; i++) {
data[i] = (byte) (sb.charAt(i));
}
String result = null;
try {
result = new String(data, UTF_ENCODE);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
//clear buffer
sb.delete(0, sb.length());
return result;
}
}
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